Harald Alfred Stenmark

• Kournoutis, Athanasios & Stenmark, Harald Alfred (2026). Sealing and healing: A two-step model for plasma membrane repair. Developmental Cell. ISSN 1534-5807. 61(7), s. 1345–1346. doi: 10.1016/j.devcel.2026.06.011. Fulltekst i vitenarkiv Vis sammendrag

  Plasma membrane damage can cause cell death and is associated with neurodegeneration. In this issue of Developmental Cell, Heffner et al. show that annexin A11 (ANXA11) first plugs membrane lesions, before ESCRT-III is recruited to extrude the damaged patch-a two-step repair mechanism compromised by ALS- and FTD-linked mutations.

• Kostas, Michal Janusz; Munthe, Else; Haugsten, Ellen Margrethe; Mateus, Duarte Nunes de Carvalho; Sørensen, Vigdis & Lærdahl, Jon Kristen [Vis alle 13 forfattere av denne artikkelen] (2026). Unconventional activation of the proto-oncogene FGFR1 by extracellular phosphate via H<inf>2</inf>O<inf>2</inf>-mediated kinase oxidation. Cell reports. 45(6). doi: 10.1016/j.celrep.2026.117504. Fulltekst i vitenarkiv
• Hurley, James H.; Coyne, Alyssa N.; Miączyńska, Marta & Stenmark, Harald Alfred (2025). The expanding repertoire of ESCRT functions in cell biology and disease. Nature. ISSN 0028-0836. 642(8069), s. 877–888. doi: 10.1038/s41586-025-08950-y. Fulltekst i vitenarkiv
• Radulovic, Maja; Yang, Chonglin & Stenmark, Harald Alfred (2025). Lysosomal membrane homeostasis and its importance in physiology and disease. Nature reviews. Molecular cell biology. ISSN 1471-0072. 27(1), s. 71–87. doi: 10.1038/s41580-025-00873-w. Fulltekst i vitenarkiv
• Haukaas, Håvard Styrkestad & Stenmark, Harald Alfred (2025). Phosphoinositides as regulators of membrane contact sites. Biochimica et Biophysica Acta - Molecular and Cell Biology of Lipids. ISSN 1388-1981. 1870(7). doi: 10.1016/j.bbalip.2025.159673. Fulltekst i vitenarkiv Vis sammendrag

  Membrane contact sites (MCSs) between the different compartments of the cell play important roles in lipid, protein and ion transfer. Phosphoinositides are crucial for the functions of many MCSs, either as membrane anchors for MCS proteins, or as part of a countertransport mechanism driven by phosphoinositide dephosphorylation in the endoplasmic reticulum. Here we review the involvement of phosphoinositides in MCSs between the endoplasmic reticulum and other organelles such as the plasma membrane, mitochondria, endosomes, lysosomes, autophagosomes and the Golgi complex. These phosphoinositide-containing MCSs mediate transfer of Ca2+, phospholipids, cholesterol, and a motor protein, and thus are of great importance for cellular physiology.

• Zhen, Yan & Stenmark, Harald Alfred (2025). Sustained release of cytokines from migrasomes. Extracellular Vesicles and Circulating Nucleic Acids (EVCNA). 6, s. 171–175. doi: 10.20517/evcna.2025.15. Fulltekst i vitenarkiv Vis sammendrag

  Cytokines are released by cells in response to infections and tissue damage. A recent paper by Jiao et al. demonstrates that circulating monocytes release the cytokines tumor necrosis factor and Interleukin-6 encapsulated in large extracellular vesicles called migrasomes, from which the cytokines are secreted locally in a sustained fashion.

• Zhen, Yan & Stenmark, Harald Alfred (2024). A dual-purpose fusion complex in autophagy. Cell Research. ISSN 1001-0602. doi: 10.1038/s41422-023-00925-w. Fulltekst i vitenarkiv
• Zhen, Yan & Stenmark, Harald Alfred (2024). Exosome regulation by Rubicon in ageing. Nature Cell Biology. ISSN 1465-7392. 26, s. 1380–1381. doi: 10.1038/s41556-024-01482-z. Fulltekst i vitenarkiv
• Wenzel, Eva; Pedersen, Nina Marie; Elfmark, Liv Anker; Ling, Wang; Kjos, Ingrid & Stang, Espen [Vis alle 10 forfattere av denne artikkelen] (2024). Intercellular transfer of cancer cell invasiveness via endosome-mediated protease shedding. Nature Communications. 15. doi: 10.1038/s41467-024-45558-8. Fulltekst i vitenarkiv Vis sammendrag

  Overexpression of the transmembrane matrix metalloproteinase MT1-MMP/MMP14 promotes cancer cell invasion. Here we show that MT1-MMP-positive cancer cells turn MT1-MMP-negative cells invasive by transferring a soluble catalytic ectodomain of MT1-MMP. Surprisingly, this effect depends on the presence of TKS4 and TKS5 in the donor cell, adaptor proteins previously implicated in invadopodia formation. In endosomes of the donor cell, TKS4/5 promote ADAM-mediated cleavage of MT1-MMP by bridging the two proteases, and cleavage is stimulated by the low intraluminal pH of endosomes. The bridging depends on the PX domains of TKS4/5, which coincidently interact with the cytosolic tail of MT1-MMP and endosomal phosphatidylinositol 3-phosphate. MT1-MMP recruits TKS4/5 into multivesicular endosomes for their subsequent co-secretion in extracellular vesicles, together with the enzymatically active ectodomain. The shed ectodomain converts non-invasive recipient cells into an invasive phenotype. Thus, TKS4/5 promote intercellular transfer of cancer cell invasiveness by facilitating ADAM-mediated shedding of MT1-MMP in acidic endosomes.

• Brugger, Melanie; Lauri, Antonella; Zhen, Yan; Gramegna, Laura L.; Zott, Benedikt & Sekulic, Nikolina [Vis alle 40 forfattere av denne artikkelen] (2024). Bi-allelic variants in SNF8 cause a disease spectrum ranging from severe developmental and epileptic encephalopathy to syndromic optic atrophy. American Journal of Human Genetics. ISSN 0002-9297. 111(3), s. 594–613. doi: 10.1016/j.ajhg.2024.02.005. Fulltekst i vitenarkiv Vis sammendrag

  The endosomal sorting complex required for transport (ESCRT) machinery is essential for membrane remodeling and autophagy and it comprises three multi-subunit complexes (ESCRT I-III). We report nine individuals from six families presenting with a spectrum of neurodevelopmental/neurodegenerative features caused by bi-allelic variants in SNF8 (GenBank: NM_007241.4), encoding the ESCRT-II subunit SNF8. The phenotypic spectrum included four individuals with severe developmental and epileptic encephalopathy, massive reduction of white matter, hypo-/aplasia of the corpus callosum, neurodevelopmental arrest, and early death. A second cohort shows a milder phenotype with intellectual disability, childhood-onset optic atrophy, or ataxia. All mildly affected individuals shared the same hypomorphic variant, c.304G>A (p.Val102Ile). In patient-derived fibroblasts, bi-allelic SNF8 variants cause loss of ESCRT-II subunits. Snf8 loss of function in zebrafish results in global developmental delay and altered embryo morphology, impaired optic nerve development, and reduced forebrain size. In vivo experiments corroborated the pathogenicity of the tested SNF8 variants and their variable impact on embryo development, validating the observed clinical heterogeneity. Taken together, we conclude that loss of ESCRT-II due to bi-allelic SNF8 variants is associated with a spectrum of neurodevelopmental/neurodegenerative phenotypes mediated likely via impairment of the autophagic flux.

• Nähse, Viola; Stenmark, Harald Alfred & Schink, Kay Oliver (2024). Omegasomes control formation, expansion, and closure of autophagosomes. Bioessays. ISSN 0265-9247. 46(6). doi: 10.1002/bies.202400038. Fulltekst i vitenarkiv Vis sammendrag

  Autophagy, an essential cellular process for maintaining cellular homeostasis and eliminating harmful cytoplasmic objects, involves the de novo formation of double-membraned autophagosomes that engulf and degrade cellular debris, protein aggregates, damaged organelles, and pathogens. Central to this process is the phagophore, which forms from donor membranes rich in lipids synthesized at various cellular sites, including the endoplasmic reticulum (ER), which has emerged as a primary source. The ER-associated omegasomes, characterized by their distinctive omega-shaped structure and accumulation of phosphatidylinositol 3-phosphate (PI3P), play a pivotal role in autophagosome formation. Omegasomes are thought to serve as platforms for phagophore assembly by recruiting essential proteins such as DFCP1/ZFYVE1 and facilitating lipid transfer to expand the phagophore. Despite the critical importance of phagophore biogenesis, many aspects remain poorly understood, particularly the complete range of proteins involved in omegasome dynamics, and the detailed mechanisms of lipid transfer and membrane contact site formation.

• Elfmark, Liv Anker; Wenzel, Eva; Ling, Wang; Pedersen, Nina Marie; Stenmark, Harald Alfred & Raiborg, Camilla (2023). Protrudin-mediated ER-endosome contact sites promote phagocytosis. Cellular and Molecular Life Sciences (CMLS). ISSN 1420-682X. 80(8), s. 1–19. doi: 10.1007/s00018-023-04862-0. Fulltekst i vitenarkiv Vis sammendrag

  Abstract During phagocytosis, endosomes both contribute with membrane to forming phagosomes and promote phagosome maturation. However, how these vesicles are delivered to the phagocytic cup and the phagosome has been unknown. Here, we show that Protrudin-mediated endoplasmic reticulum (ER)-endosome contact sites facilitate anterograde translocation of FYCO1 and VAMP7-positive late endosomes and lysosomes (LELys) to forming phagocytic cups in a retinal pigment epithelial-derived cell line (RPE1). Protrudin-dependent phagocytic cup formation required SYT7, which promotes fusion of LELys with the plasma membrane. RPE1 cells perform phagocytosis of dead cells (efferocytosis) that expose phosphatidylserine (PS) on their surface. Exogenous addition of apoptotic bodies increased the formation of phagocytic cups, which further increased when Protrudin was overexpressed. Overexpression of Protrudin also led to elevated uptake of silica beads coated with PS. Conversely, Protrudin depletion or abrogation of ER-endosome contact sites inhibited phagocytic cup formation resulting in reduced uptake of PS-coated beads. Thus, the Protrudin pathway delivers endosomes to facilitate formation of the phagocytic cup important for PS-dependent phagocytosis.

• Migliano, Simona Maria; Schultz, Sebastian Wolfgang; Wenzel, Eva; Takats, Szabolcs; Liu, Dan & mørk, silje [Vis alle 10 forfattere av denne artikkelen] (2023). Removal of hypersignaling endosomes by simaphagy. Autophagy. ISSN 1554-8627. s. 1–23. doi: 10.1080/15548627.2023.2267958. Fulltekst i vitenarkiv Vis sammendrag

  Activated transmembrane receptors continue to signal following endocytosis and are only silenced upon ESCRT-mediated internalization of the receptors into intralumenal vesicles (ILVs) of the endosomes. Accordingly, endosomes with dysfunctional receptor internalization into ILVs can cause sustained receptor signaling which has been implicated in cancer progression. Here, we describe a surveillance mechanism that allows cells to detect and clear physically intact endosomes with aberrant receptor accumulation and elevated signaling. Proximity biotinylation and proteomics analyses of ESCRT-0 defective endosomes revealed a strong enrichment of the ubiquitin-binding macroautophagy/autophagy receptors SQSTM1 and NBR1, a phenotype that was confirmed in cell culture and fly tissue. Live cell microscopy demonstrated that loss of the ESCRT-0 subunit HGS/HRS or the ESCRT-I subunit VPS37 led to high levels of ubiquitinated and phosphorylated receptors on endosomes. This was accompanied by dynamic recruitment of NBR1 and SQSTM1 as well as proteins involved in autophagy initiation and autophagosome biogenesis. Light microscopy and electron tomography revealed that endosomes with intact limiting membrane, but aberrant receptor downregulation were engulfed by phagophores. Inhibition of autophagy caused increased intra- and intercellular signaling and directed cell migration. We conclude that dysfunctional endosomes are surveyed and cleared by an autophagic process, simaphagy, which serves as a failsafe mechanism in signal termination.

• Clement, Dennis; Szabo, Edina Krisztina; Krokeide, Silje Zandstra; Wiiger, Merete Thune; Vincenti, Marianna & Orellana, Daniel Alfredo Palacios [Vis alle 13 forfattere av denne artikkelen] (2023). The Lysosomal Calcium Channel TRPML1 Maintains Mitochondrial Fitness in NK Cells through Interorganelle Cross-Talk. Journal of Immunology. ISSN 0022-1767. 211(9), s. 1348–1358. doi: 10.4049/jimmunol.2300406. Fulltekst i vitenarkiv Vis sammendrag

  Abstract Cytotoxic lymphocytes eliminate cancer cells through the release of lytic granules, a specialized form of secretory lysosomes. This compartment is part of the pleomorphic endolysosomal system and is distinguished by its highly dynamic Ca2+ signaling machinery. Several transient receptor potential (TRP) calcium channels play essential roles in endolysosomal Ca2+ signaling and ensure the proper function of these organelles. In this study, we examined the role of TRPML1 (TRP cation channel, mucolipin subfamily, member 1) in regulating the homeostasis of secretory lysosomes and their cross-talk with mitochondria in human NK cells. We found that genetic deletion of TRPML1, which localizes to lysosomes in NK cells, led to mitochondrial fragmentation with evidence of collapsed mitochondrial cristae. Consequently, TRPML1−/− NK92 (NK92ML1−/−) displayed loss of mitochondrial membrane potential, increased reactive oxygen species stress, reduced ATP production, and compromised respiratory capacity. Using sensitive organelle-specific probes, we observed that mitochondria in NK92ML1−/− cells exhibited evidence of Ca2+ overload. Moreover, pharmacological activation of the TRPML1 channel in primary NK cells resulted in upregulation of LC3-II, whereas genetic deletion impeded autophagic flux and increased accumulation of dysfunctional mitochondria. Thus, TRPML1 impacts autophagy and clearance of damaged mitochondria. Taken together, these results suggest that an intimate interorganelle communication in NK cells is orchestrated by the lysosomal Ca2+ channel TRPML1.

• Kaur, Namrita; Ballina, Laura R de la; Haukaas, Håvard Styrkestad; Torgersen, Maria Lyngaas; Radulovic, Maja & Munson, Michael J [Vis alle 11 forfattere av denne artikkelen] (2023). TECPR1 is activated by damage-induced sphingomyelin exposure to mediate noncanonical autophagy. EMBO Journal. ISSN 0261-4189. 42(17), s. 1–19. doi: 10.15252/embj.2022113105. Fulltekst i vitenarkiv Vis sammendrag

  Abstract Cells use noncanonical autophagy, also called conjugation of ATG8 to single membranes (CASM), to label damaged intracellular compartments with ubiquitin‐like ATG8 family proteins in order to signal danger caused by pathogens or toxic compounds. CASM relies on E3 complexes to sense membrane damage, but so far, only the mechanism to activate ATG16L1‐containing E3 complexes, associated with proton gradient loss, has been described. Here, we show that TECPR1‐containing E3 complexes are key mediators of CASM in cells treated with a variety of pharmacological drugs, including clinically relevant nanoparticles, transfection reagents, antihistamines, lysosomotropic compounds, and detergents. Interestingly, TECPR1 retains E3 activity when ATG16L1 CASM activity is obstructed by the Salmonella Typhimurium pathogenicity factor SopF. Mechanistically, TECPR1 is recruited by damage‐induced sphingomyelin (SM) exposure using two DysF domains, resulting in its activation and ATG8 lipidation. In vitro assays using purified human TECPR1‐ATG5‐ATG12 complex show direct activation of its E3 activity by SM, whereas SM has no effect on ATG16L1‐ATG5‐ATG12. We conclude that TECPR1 is a key activator of CASM downstream of SM exposure.

• Kang, Jiwon; Yoo, Young Jin; Park, Jin-Hwi; Ko, Joo Hwan; Kim, Seungtaek & Stanciu, Stefan G. [Vis alle 11 forfattere av denne artikkelen] (2023). DeepGT: Deep learning-based quantification of nanosized bioparticles in bright-field micrographs of Gires-Tournois biosensor. Nano Today. ISSN 1748-0132. 52. doi: 10.1016/j.nantod.2023.101968. Fulltekst i vitenarkiv
• Nähse, Viola; Schink, Kay Oliver & Stenmark, Harald Alfred (2023). ATPase-regulated autophagosome biogenesis. Autophagy. ISSN 1554-8627. 20(1), s. 218–219. doi: 10.1080/15548627.2023.2255967. Fulltekst i vitenarkiv Vis sammendrag

  Omega-shaped domains of the endoplasmic reticulum, known as omegasomes, have been suggested to contribute to autophagosome biogenesis, although their exact function is not known. Omegasomes are characterized by the presence of the double FYVE domain containing protein ZFYVE1/DFCP1, but it has remained a paradox that depletion of ZFYVE1 does not prevent bulk macroautophagy/autophagy. We recently showed that ZFYVE1 contains an N-terminal ATPase domain which dimerizes upon ATP binding. Mutations in the ATPase domain that inhibit ATP binding or hydrolysis do not prevent omegasome expansion and maturation. However, omegasome constriction is inhibited by these mutations, which results in an increased lifetime and thereby higher number of omegasomes. Interestingly, whereas ZFYVE1 knockout or mutations do not significantly affect bulk autophagy, selective autophagy of mitochondria, protein aggregates and micronuclei is inhibited. We propose that ATP binding and hydrolysis control the di- or multimerization state of ZFYVE1 which could provide the mechanochemical energy to drive large omegasome constriction and autophagosome completion.

• Davies, Elizabeth Michele; Mitchell, Christina Anne & Stenmark, Harald Alfred (2023). Phosphoinositides in New Spaces. Cold Spring Harbor Perspectives in Biology. 15(9), s. 1–32. doi: 10.1101/cshperspect.a041406. Fulltekst i vitenarkiv
• Zhen, Yan & Stenmark, Harald Alfred (2023). Autophagosome biogenesis. Cells. 12:668(4), s. 1–15. doi: 10.3390/cells12040668. Fulltekst i vitenarkiv Vis sammendrag

  Autophagy–the lysosomal degradation of cytoplasm–plays a central role in cellular homeostasis and protects cells from potentially harmful agents that may accumulate in the cytoplasm, including pathogens, protein aggregates, and dysfunctional organelles. This process is initiated by the formation of a phagophore membrane, which wraps around a portion of cytoplasm or cargo and closes to form a double-membrane autophagosome. Upon the fusion of the autophagosome with a lysosome, the sequestered material is degraded by lysosomal hydrolases in the resulting autolysosome. Several alternative membrane sources of autophagosomes have been proposed, including the plasma membrane, endosomes, mitochondria, endoplasmic reticulum, lipid droplets, hybrid organelles, and de novo synthesis. Here, we review recent progress in our understanding of how the autophagosome is formed and highlight the proposed role of vesicles that contain the lipid scramblase ATG9 as potential seeds for phagophore biogenesis. We also discuss how the phagophore is sealed by the action of the endosomal sorting complex required for transport (ESCRT) proteins.

• Raiborg, Camilla; Tan, Kia Wee; Mørk, Sissel; Torgersen, Maria Lyngaas; Wenzel, Eva & Grifo, Mireia Nager [Vis alle 12 forfattere av denne artikkelen] (2023). ATPase activity of DFCP1 controls selective autophagy. Nature Communications. 14(1). doi: 10.1038/s41467-023-39641-9. Fulltekst i vitenarkiv Vis sammendrag

  Cellular homeostasis is governed by removal of damaged organelles and protein aggregates by selective autophagy mediated by cargo adaptors such as p62/SQSTM1. Autophagosomes can assemble in specialized cup-shaped regions of the endoplasmic reticulum (ER) known as omegasomes, which are characterized by the presence of the ER protein DFCP1/ZFYVE1. The function of DFCP1 is unknown, as are the mechanisms of omegasome formation and constriction. Here, we demonstrate that DFCP1 is an ATPase that is activated by membrane binding and dimerizes in an ATP-dependent fashion. Whereas depletion of DFCP1 has a minor effect on bulk autophagic flux, DFCP1 is required to maintain the autophagic flux of p62 under both fed and starved conditions, and this is dependent on its ability to bind and hydrolyse ATP. While DFCP1 mutants defective in ATP binding or hydrolysis localize to forming omegasomes, these omegasomes fail to constrict properly in a size-dependent manner. Consequently, the release of nascent autophagosomes from large omegasomes is markedly delayed. While knockout of DFCP1 does not affect bulk autophagy, it inhibits selective autophagy, including aggrephagy, mitophagy and micronucleophagy. We conclude that DFCP1 mediates ATPase-driven constriction of large omegasomes to release autophagosomes for selective autophagy.

• Zhen, Yan & Stenmark, Harald Alfred (2023). A phosphoinositide kinase triggers migrasome formation. Cell Research. ISSN 1001-0602. 33(8), s. 577–578. doi: 10.1038/s41422-023-00822-2. Fulltekst i vitenarkiv
• Pust, Sascha; Brech, Andreas; Wegner, Catherine E Sem; Stenmark, Harald Alfred & Haglund, Kaisa Louise Ingeborg (2023). Vesicle-mediated transport of ALIX and ESCRT-III to the intercellular bridge during cytokinesis. Cellular and Molecular Life Sciences (CMLS). ISSN 1420-682X. 80(8), s. 1–18. doi: 10.1007/s00018-023-04864-y. Fulltekst i vitenarkiv Vis sammendrag

  Abstract Cellular abscission is the final step of cytokinesis that leads to the physical separation of the two daughter cells. The scaffold protein ALIX and the ESCRT-I protein TSG101 contribute to recruiting ESCRT-III to the midbody, which orchestrates the final membrane scission of the intercellular bridge. Here, we addressed the transport mechanisms of ALIX and ESCRT-III subunit CHMP4B to the midbody. Structured illumination microscopy revealed gradual accumulation of ALIX at the midbody, resulting in the formation of spiral-like structures extending from the midbody to the abscission site, which strongly co-localized with CHMP4B. Live-cell microscopy uncovered that ALIX appeared together with CHMP4B in vesicular structures, whose motility was microtubule-dependent. Depletion of ALIX led to structural alterations of the midbody and delayed recruitment of CHMP4B, resulting in delayed abscission. Likewise, depletion of the kinesin-1 motor KIF5B reduced the motility of ALIX-positive vesicles and delayed midbody recruitment of ALIX, TSG101 and CHMP4B, accompanied by impeded abscission. We propose that ALIX, TSG101 and CHMP4B are associated with endosomal vesicles transported on microtubules by kinesin-1 to the cytokinetic bridge and midbody, thereby contributing to their function in abscission.

• Radulovic, Maja; Wenzel, Eva; Gilani, Sania; Holland, Lya KK; Lystad, Alf Håkon Lohsen & Phuyal, Santosh [Vis alle 12 forfattere av denne artikkelen] (2022). Cholesterol transfer via endoplasmic reticulum contacts mediates lysosome damage repair. EMBO Journal. ISSN 0261-4189. 41:e112677, s. 1–18. doi: 10.15252/embj.2022112677. Fulltekst i vitenarkiv Vis sammendrag

  Lysosome integrity is essential for cell viability, and lesions in lysosome membranes are repaired by the ESCRT machinery. Here, we describe an additional mechanism for lysosome repair that is activated independently of ESCRT recruitment. Lipidomic analyses showed increases in lysosomal phosphatidylserine and cholesterol after damage. Electron microscopy demonstrated that lysosomal membrane damage is rapidly followed by the formation of contacts with the endoplasmic reticulum (ER), which depends on the ER proteins VAPA/B. The cholesterol-binding protein ORP1L was recruited to damaged lysosomes, accompanied by cholesterol accumulation by a mechanism that required VAP–ORP1L interactions. The PtdIns 4-kinase PI4K2A rapidly produced PtdIns4P on lysosomes upon damage, and knockout of PI4K2A inhibited damage-induced accumulation of ORP1L and cholesterol and led to the failure of lysosomal membrane repair. The cholesterol–PtdIns4P transporter OSBP was also recruited upon damage, and its depletion caused lysosomal accumulation of PtdIns4P and resulted in cell death. We conclude that ER contacts are activated on damaged lysosomes in parallel to ESCRTs to provide lipids for membrane repair, and that PtdIns4P generation and removal are central in this response.

• Romaine, Andreas; Melleby, Arne Olav; Alam, Jahedul; Lobert, Viola; Lu, Ning & Lockwood, Francesca Eve [Vis alle 13 forfattere av denne artikkelen] (2022). Integrin α11β1 and syndecan-4 dual receptor ablation attenuates cardiac hypertrophy in the pressure overloaded heart. American Journal of Physiology. Heart and Circulatory Physiology. ISSN 0363-6135. 322(6), s. H1057–H1071. doi: 10.1152/ajpheart.00635.2021. Fulltekst i vitenarkiv
• Stanciu, Stefan G.; Hristu, Radu; Stanciu, George A.; Tranca, Denis E.; Eftimie, Lucian & Dumitru, Adrian [Vis alle 12 forfattere av denne artikkelen] (2022). Super-resolution re-scan second harmonic generation microscopy. Proceedings of the National Academy of Sciences of the United States of America (PNAS). ISSN 0027-8424. 119(47), s. 1–3. doi: 10.1073/pnas.2214662119. Fulltekst i vitenarkiv Vis sammendrag

  Second harmonic generation microscopy (SHG) is generally acknowledged as a powerful tool for the label-free three-dimensional visualization of tissues and advanced materials, with one of its most popular applications being collagen imaging. Despite the great need, progress in super-resolved SHG imaging lags behind the developments reported over the past years in fluorescence-based optical nanoscopy. In this work, we demonstrate super-resolved re-scan SHG, qualitatively and quantitatively showing on collagenous tissues the available resolution advantage over the diffraction limit. We introduce as well super-resolved re-scan two-photon excited fluorescence microscopy, an imaging modality not explored to date.

• Migliano, Simona Maria; Wenzel, Eva & Stenmark, Harald (2022). Biophysical and molecular mechanisms of ESCRT functions, and their implications for disease. Current Opinion in Cell Biology. ISSN 0955-0674. 75, s. 1–8. doi: 10.1016/j.ceb.2022.01.007. Fulltekst i vitenarkiv Vis sammendrag

  The endosomal sorting complex required for transport (ESCRT) machinery evolved early in evolution to sculpt and cut cellular membranes. Consisting of three subcomplexes termed ESCRT-I, -II and -III, this machinery is recruited to various cellular locations to perform key steps in essential processes such as protein degradation, cell division, and membrane sealing. Here we review recent discoveries that have shed light on biophysical and molecular mechanisms of ESCRTs in endolysosomal protein degradation and nuclear envelope sealing, and we discuss how dysfunctional ESCRTs can lead to diseases such as cancer and neurodegenerative disorders.

• Lobert, Viola; Skardal, Maren; Malerød, Lene; Simensen, Julie Elisabeth; Algra, Hermine Arida & Andersen, Aram Nikolai [Vis alle 12 forfattere av denne artikkelen] (2022). PHLPP1 regulates CFTR activity and lumen expansion through AMPK. Development. ISSN 0950-1991. 149(20), s. 1–10. doi: 10.1242/dev.200955. Fulltekst i vitenarkiv Vis sammendrag

  Complex organ development depends on single lumen formation and its expansion during tubulogenesis. This can be achieved by correct mitotic spindle orientation during cell division, combined with luminal fluid filling that generates hydrostatic pressure. Using a human 3D cell culture model, we have identified two regulators of these processes. We find that pleckstrin homology leucine-rich repeat protein phosphatase (PHLPP) 2 regulates mitotic spindle orientation, and thereby midbody positioning and maintenance of a single lumen. Silencing the sole PHLPP family phosphatase in Drosophila melanogaster, phlpp, resulted in defective spindle orientation in Drosophila neuroblasts. Importantly, cystic fibrosis transmembrane conductance regulator (CFTR) is the main channel regulating fluid transport in this system, stimulated by phosphorylation by protein kinase A and inhibited by the AMP-activated protein kinase AMPK. During lumen expansion, CFTR remains open through the action of PHLPP1, which stops activated AMPK from inhibiting ion transport through CFTR. In the absence of PHLPP1, the restraint on AMPK activity is lost and this tips the balance in the favour of channel closing, resulting in the lack of lumen expansion and accumulation of mucus.

• Du, Hui; Yang, Fang; Yao, Chenyang; Lv, Wenhao; Peng, Hao & Stanciu, Stefan G. [Vis alle 10 forfattere av denne artikkelen] (2022). “Double-punch” strategy against triple-negative breast cancer via a synergistic therapy of magneto-mechanical force enhancing NIR-II hypothermal ablation. Biomaterials. ISSN 0142-9612. 291:121868. doi: 10.1016/j.biomaterials.2022.121868. Fulltekst i vitenarkiv
• Migliano, Simona Maria & Stenmark, Harald (2022). ESCRTed resistance to T cell attack. Trends in immunology. ISSN 1471-4906. 43(8), s. 598–600. doi: 10.1016/j.it.2022.06.007. Fulltekst i vitenarkiv Vis sammendrag

  Cytotoxic T cells kill target cells such as cancer cells by making pores in their plasma membrane through which toxic enzymes are secreted. Ritter and colleagues now show that cancer cells can actively remove such pores via the action of endosomal sorting complex required for transport (ESCRT) proteins, thereby counteracting CD8+ T cell-mediated killing.

• Wenzel, Eva; Elfmark, Liv Anker; Stenmark, Harald & Raiborg, Camilla (2022). ER as master regulator of membrane trafficking and organelle function. Journal of Cell Biology. ISSN 0021-9525. 221(10), s. 1–19. doi: 10.1083/jcb.202205135. Fulltekst i vitenarkiv Vis sammendrag

  The endoplasmic reticulum (ER), which occupies a large portion of the cytoplasm, is the cell’s main site for the biosynthesis of lipids and carbohydrate conjugates, and it is essential for folding, assembly, and biosynthetic transport of secreted proteins and integral membrane proteins. The discovery of abundant membrane contact sites (MCSs) between the ER and other membrane compartments has revealed that, in addition to its biosynthetic and secretory functions, the ER plays key roles in the regulation of organelle dynamics and functions. In this review, we will discuss how the ER regulates endosomes, lysosomes, autophagosomes, mitochondria, peroxisomes, and the Golgi apparatus via MCSs. Such regulation occurs via lipid and Ca2+ transfer and also via control of in trans dephosphorylation reactions and organelle motility, positioning, fusion, and fission. The diverse controls of other organelles via MCSs manifest the ER as master regulator of organelle biology.

• Du, Hui; Yang, Fang; Yao, Chenyang; Zhong, Zhicheng; Jiang, Peiheng & Stanciu, Stefan G. [Vis alle 14 forfattere av denne artikkelen] (2022). Multifunctional Modulation of High-Performance Zn<inf>x</inf>Fe<inf>3−x</inf>O<inf>4</inf> Nanoparticles by Precisely Tuning the Zinc Doping Content. Small. ISSN 1613-6810. 18(42), s. 1–14. doi: 10.1002/smll.202201669. Fulltekst i vitenarkiv
• Stanciu, Stefan G.; Tranca, Denis E.; Zampini, Giulia; Hristu, Radu; Stanciu, George A. & Chen, Xinzhong [Vis alle 9 forfattere av denne artikkelen] (2022). Scattering-type Scanning Near-Field Optical Microscopy of Polymer-Coated Gold Nanoparticles. ACS Omega. 7(13), s. 11353–11362. doi: 10.1021/acsomega.2c00410. Fulltekst i vitenarkiv
• Zhen, Yan; Radulovic, Maja; Vietri, Marina & Stenmark, Harald (2021). Sealing holes in cellular membranes. EMBO Journal. ISSN 0261-4189. 40:e106922, s. 1–13. doi: 10.15252/embj.2020106922. Fulltekst i vitenarkiv Vis sammendrag

  The compartmentalization of eukaryotic cells, which is essential for their viability and functions, is ensured by single or double bilayer membranes that separate the cell from the exterior and form boundaries between the cell’s organelles and the cytosol. Nascent nuclear envelopes and autophagosomes, which both are enveloped by double membranes, need to be sealed during the late stage of their biogenesis. On the other hand, the integrity of cellular membranes such as the plasma membrane, lysosomes and the nuclear envelope can be compromised by pathogens, chemicals, radiation, inflammatory responses and mechanical stress. There are cellular programmes that restore membrane integrity after injury. Here, we review cellular mechanisms that have evolved to maintain membrane integrity during organelle biogenesis and after injury, including membrane scission mediated by the endosomal sorting complex required for transport (ESCRT), vesicle patching and endocytosis.

• Nähse, Viola; Tan, Kia Wee; Campsteijn, Coen; Brech, Andreas; Schink, Kay Oliver & Stenmark, Harald (2021). JIP4 is recruited by the phosphoinositide-binding protein Phafin2 to promote recycling tubules on macropinosomes. Journal of Cell Science. ISSN 0021-9533. 134(14), s. 1–15. doi: 10.1242/jcs.258495. Fulltekst i vitenarkiv Vis sammendrag

  ABSTRACT Macropinocytosis allows cells to take up extracellular material in a non-selective manner into large vesicles called macropinosomes. After internalization, macropinosomes acquire phosphatidylinositol 3-phosphate (PtdIns3P) on their limiting membrane as they mature into endosomal-like vesicles. The molecular mechanisms that underlie recycling of membranes and transmembrane proteins from these macropinosomes still need to be defined. Here, we report that JIP4 (officially known as SPAG9), a protein previously described to bind to microtubule motors, is recruited to tubulating subdomains on macropinosomes by the PtdIns3P-binding protein Phafin2 (officially known as PLEKHF2). These JIP4-positive tubulating subdomains on macropinosomes contain F-actin, the retromer recycling complex and the retromer cargo VAMP3. Disruption of the JIP4–Phafin2 interaction, deletion of Phafin2 or inhibition of PtdIns3P production by VPS34 impairs JIP4 recruitment to macropinosomes. Whereas knockout of JIP4 suppresses tubulation, its overexpression enhances tubulation from macropinosomes. JIP4-knockout cells display increased retention of macropinocytic cargo in both early and late macropinosomes. Collectively, these data identify JIP4 and Phafin2 as components of a tubular recycling pathway that operates from macropinosomes. This article has an associated First Person interview with the first author of the paper.

• Janssen, Mathijs Adriaan; Stenmark, Harald & Carlson, Andreas (2021). Divalent ligand-monovalent molecule binding. Soft Matter. ISSN 1744-683X. 17, s. 5375–5383. doi: 10.1039/d1sm00070e. Fulltekst i vitenarkiv Vis sammendrag

  Simultaneous binding of a divalent ligand to two identical monovalent molecules is a widespread phenomenon in biology and chemistry. Here, we describe how two such monovalent molecules B bind to a divalent ligand AA to form the intermediate and final complexes AA·B and AA·B2. Cases wherein the total concentration [AA]T is either much larger or much smaller than the total concentration [B]T have been studied earlier, but a systematic description of comparable concentrations [AA]T and [B]T is missing. Here, we present numerical and analytical results for the concentrations [AA·B] and [AA·B2] for the entire range 0

• Schink, Kay Oliver; Tan, Kia Wee; Spangenberg, Helene; Martorana, Domenica; Sneeggen, Marte & Stévenin, Virginie [Vis alle 10 forfattere av denne artikkelen] (2021). The phosphoinositide coincidence detector Phafin2 promotes macropinocytosis by coordinating actin organisation at forming macropinosomes. Nature Communications. 12(1), s. 1–17. doi: 10.1038/s41467-021-26775-x. Fulltekst i vitenarkiv Vis sammendrag

  Abstract Uptake of large volumes of extracellular fluid by actin-dependent macropinocytosis has an important role in infection, immunity and cancer development. A key question is how actin assembly and disassembly are coordinated around macropinosomes to allow them to form and subsequently pass through the dense actin network underlying the plasma membrane to move towards the cell center for maturation. Here we show that the PH and FYVE domain protein Phafin2 is recruited transiently to newly-formed macropinosomes by a mechanism that involves coincidence detection of PtdIns3P and PtdIns4P. Phafin2 also interacts with actin via its PH domain, and recruitment of Phafin2 coincides with actin reorganization around nascent macropinosomes. Moreover, forced relocalization of Phafin2 to the plasma membrane causes rearrangement of the subcortical actin cytoskeleton. Depletion of Phafin2 inhibits macropinosome internalization and maturation and prevents KRAS-transformed cancer cells from utilizing extracellular protein as an amino acid source. We conclude that Phafin2 promotes macropinocytosis by controlling timely delamination of actin from nascent macropinosomes for their navigation through the dense subcortical actin network.

• Zdzalik-Bielecka, Daria; Poswiata, Agata; Kozik, Kamila; Jastrzębski, Kamil; Schink, Kay Oliver & Brewinska-Olchowik, Marta [Vis alle 9 forfattere av denne artikkelen] (2021). The GAS6-AXL signaling pathway triggers actin remodeling that drives membrane ruffling, macropinocytosis, and cancer-cell invasion. Proceedings of the National Academy of Sciences of the United States of America (PNAS). ISSN 0027-8424. 118(28). doi: 10.1073/pnas.2024596118. Fulltekst i vitenarkiv
• Ravussin, Anthony; Brech, Andreas; Tooze, Sharon A. & Stenmark, Harald (2021). The phosphatidylinositol 3-phosphate-binding protein SNX4 controls ATG9A recycling and autophagy. Journal of Cell Science. ISSN 0021-9533. 134(3), s. 1–11. doi: 10.1242/jcs.250670. Fulltekst i vitenarkiv Vis sammendrag

  ABSTRACT Late endosomes and lysosomes (endolysosomes) receive proteins and cargo from the secretory, endocytic and autophagic pathways. Although these pathways and the degradative processes of endolysosomes are well characterized, less is understood about protein traffic from these organelles. In this study, we demonstrate the direct involvement of the phosphatidylinositol 3-phosphate (PI3P)-binding SNX4 protein in membrane protein recycling from endolysosomes, and show that SNX4 is required for proper autophagic flux. We show that SNX4 mediates recycling of the lipid scramblase ATG9A, which drives expansion of nascent autophagosome membranes, from endolysosomes to early endosomes, from where ATG9A is recycled to the trans-Golgi network in a retromer-dependent manner. Upon siRNA-mediated depletion of SNX4 or the retromer component VPS35, we observed accumulation of ATG9A on endolysosomes and early endosomes, respectively. Moreover, starvation-induced autophagosome biogenesis and autophagic flux were inhibited when SNX4 was downregulated. We propose that proper ATG9A recycling by SNX4 sustains autophagy by preventing exhaustion of the available ATG9A pool. This article has an associated First Person interview with the first author of the paper.

• Klionsky, Daniel J.; Abdel-Aziz, Amal Kamal; Abdelfatah, Sara; Abdellatif, Mahmoud Khaled; Abdoli, Asghar & Abudu, Yakubu Princely [Vis alle 50 forfattere av denne artikkelen] (2021). Guidelines for the use and interpretation of assays for monitoring autophagy (4th edition). Autophagy. ISSN 1554-8627. 17(1), s. 1–382. doi: https:/www.tandfonline.com/doi/full/10.1080/15548627.2020.1797280. Fulltekst i vitenarkiv
• Schultz, Sebastian; Agudo-Canalejo, Jaime; Chino, Haruka; Migliano, Simona; Saito, Chieko & Koyama-Honda, Ikuko [Vis alle 11 forfattere av denne artikkelen] (2021). Should I bend or should I grow: the mechanisms of droplet-mediated autophagosome formation. Autophagy. ISSN 1554-8627. 17(4), s. 1046–1048. doi: 10.1080/15548627.2021.1887548. Fulltekst i vitenarkiv
• Pedersen, Nina Marie; Wenzel, Eva; Ling, Wang; Antoine, Sandra; Chavrier, Philippe & Stenmark, Harald Alfred [Vis alle 7 forfattere av denne artikkelen] (2020). Protrudin-mediated ER–endosome contact sites promote MT1-MMP exocytosis and cell invasion. Journal of Cell Biology. ISSN 0021-9525. 219(8), s. 1–28. doi: 10.1083/jcb.202003063. Fulltekst i vitenarkiv Vis sammendrag

  Cancer cells break tissue barriers by use of small actin-rich membrane protrusions called invadopodia. Complete invadopodia maturation depends on protrusion outgrowth and the targeted delivery of the matrix metalloproteinase MT1-MMP via endosomal transport by mechanisms that are not known. Here, we show that the ER protein Protrudin orchestrates invadopodia maturation and function. Protrudin formed contact sites with MT1-MMP–positive endosomes that contained the RAB7-binding Kinesin-1 adaptor FYCO1, and depletion of RAB7, FYCO1, or Protrudin inhibited MT1-MMP–dependent extracellular matrix degradation and cancer cell invasion by preventing anterograde translocation and exocytosis of MT1-MMP. Moreover, when endosome translocation or exocytosis was inhibited by depletion of Protrudin or Synaptotagmin VII, respectively, invadopodia were unable to expand and elongate. Conversely, when Protrudin was overexpressed, noncancerous cells developed prominent invadopodia-like protrusions and showed increased matrix degradation and invasion. Thus, Protrudin-mediated ER–endosome contact sites promote cell invasion by facilitating translocation of MT1-MMP–laden endosomes to the plasma membrane, enabling both invadopodia outgrowth and MT1-MMP exocytosis.

• Beckwith, Kai Sandvold; Beckwith, Marianne Sandvold; Ullmann, Sindre; Sætra, Ragnhild Sofie Ragnhildstveit; Kim, Hae Lin & Marstad, Anne [Vis alle 12 forfattere av denne artikkelen] (2020). Plasma membrane damage causes NLRP3 activation and pyroptosis during Mycobacterium tuberculosis infection. Nature Communications. 11:2270, s. 1–18. doi: 10.1038/s41467-020-16143-6. Fulltekst i vitenarkiv Vis sammendrag

  Mycobacterium tuberculosis is a global health problem in part as a result of extensive cytotoxicity caused by the infection. Here, we show how M. tuberculosis causes caspase-1/NLRP3/gasdermin D-mediated pyroptosis of human monocytes and macrophages. A type VII secretion system (ESX-1) mediated, contact-induced plasma membrane damage response occurs during phagocytosis of bacteria. Alternatively, this can occur from the cytosolic side of the plasma membrane after phagosomal rupture in infected macrophages. This damage causes K+ efflux and activation of NLRP3-dependent IL-1β release and pyroptosis, facilitating the spread of bacteria to neighbouring cells. A dynamic interplay of pyroptosis with ESCRT-mediated plasma membrane repair also occurs. This dual plasma membrane damage seems to be a common mechanism for NLRP3 activators that function through lysosomal damage.

• Vietri, Marina; Schultz, Sebastian; Bellanger, Aurélie Nathalie Pascale; Jones, Carl; Petersen, Louise I & Raiborg, Camilla [Vis alle 20 forfattere av denne artikkelen] (2020). Unrestrained ESCRT-III drives micronuclear catastrophe and chromosome fragmention. Nature Cell Biology. ISSN 1465-7392. 22, s. 856–867. doi: 10.1038/s41556-020-0537-5. Fulltekst i vitenarkiv Vis sammendrag

  The ESCRT-III membrane fission machinery maintains the integrity of the nuclear envelope. Although primary nuclei resealing takes minutes, micronuclear envelope ruptures seem to be irreversible. Instead, micronuclear ruptures result in catastrophic membrane collapse and are associated with chromosome fragmentation and chromothripsis, complex chromosome rearrangements thought to be a major driving force in cancer development. Here we use a combination of live microscopy and electron tomography, as well as computer simulations, to uncover the mechanism underlying micronuclear collapse. We show that, due to their small size, micronuclei inherently lack the capacity of primary nuclei to restrict the accumulation of CHMP7–LEMD2, a compartmentalization sensor that detects loss of nuclear integrity. This causes unrestrained ESCRT-III accumulation, which drives extensive membrane deformation, DNA damage and chromosome fragmentation. Thus, the nuclear-integrity surveillance machinery is a double-edged sword, as its sensitivity ensures rapid repair at primary nuclei while causing unrestrained activity at ruptured micronuclei, with catastrophic consequences for genome stability.

• Munthe, Else; Raiborg, Camilla; Stenmark, Harald & Wenzel, Eva (2020). Clathrin regulates Wnt/β-catenin signaling by affecting Golgi to plasma membrane transport of transmembrane proteins. Journal of Cell Science. ISSN 0021-9533. 133:jcs244467, s. 1–13. doi: 10.1242/jcs.244467. Fulltekst i vitenarkiv Vis sammendrag

  The canonical Wnt/β-catenin signaling pathway regulates cell proliferation in development and adult tissue homeostasis. Dysregulated signaling contributes to human diseases, in particular cancer. Growing evidence suggests a role for clathrin and/or endocytosis in the regulation of this pathway, but conflicting results exist and demand a deeper mechanistic understanding. We investigated the consequences of clathrin depletion on Wnt/β-catenin signaling in cell lines and found a pronounced reduction in β-catenin protein levels, which affects the amount of nuclear β-catenin and β-catenin target gene expression. Although we found no evidence that clathrin affects β-catenin levels via endocytosis or multivesicular endosome formation, an inhibition of protein transport through the biosynthetic pathway led to reduced levels of a Wnt co-receptor, low-density lipoprotein receptor-related protein 6 (LRP6), and cell adhesion molecules of the cadherin family, thereby affecting steady-state levels of β-catenin. We conclude that clathrin impacts on Wnt/β-catenin signaling by controlling exocytosis of transmembrane proteins, including cadherins and Wnt co-receptors that together control the membrane-bound and soluble pools of β-catenin.

• Liese, Susanne; Wenzel, Eva; Kjos, Ingrid; Molina, Rossana Virginia Rojas; Schultz, Sebastian & Brech, Andreas [Vis alle 9 forfattere av denne artikkelen] (2020). Protein crowding mediates membrane remodeling in upstream ESCRT-induced formation of intraluminal vesicles. Proceedings of the National Academy of Sciences of the United States of America (PNAS). ISSN 0027-8424. 117(46), s. 28614–28624. doi: 10.1073/pnas.2014228117. Fulltekst i vitenarkiv Vis sammendrag

  As part of the lysosomal degradation pathway, the endosomal sorting complexes required for transport (ESCRT-0-III/VPS4) sequester receptors at the endosome and simultaneously deform the membrane to generate intraluminal vesicles (ILVs). Whereas ESCRT-III/VPS4 have an established function in ILV formation, the role of upstream ESCRTs (0-II) in membrane shape remodeling is not understood. Combining experimental measurements and electron microscopy analysis of ESCRT-III depleted cells with a mathematical model, we show that upstream ESCRT-induced alteration of the Gaussian bending rigidity and their crowding in concert with the transmembrane cargo on the membrane induces membrane deformation and facilitates ILV formation: upstream ESCRT-driven budding does not require ATP consumption as only a small energy barrier needs to be overcome. Our model predicts that ESCRTs do not become part of the ILV, but localize with a high density at the membrane neck, where the steep decline in the Gaussian curvature likely triggers ESCRT-III/VPS4 assembly to enable neck constriction and scission.

• Radulovic, Maja & Stenmark, Harald Alfred (2020). LRRK2 to the rescue of damaged endomembranes. EMBO Journal. ISSN 0261-4189. 39(18), s. 1–3. doi: 10.15252/embj.2020106162. Fulltekst i vitenarkiv Vis sammendrag

  Mutations in several genes encoding for lysosomal proteins are involved in Parkinson's disease (PD). In this issue, Herbst et al (2020) show that PD-related leucine-rich repeat kinase 2 (LRRK2) is activated in response to pathogen or membranolytic drug-induced damage of phagolysosomes and lysosomes in macrophages, and regulates endolysosomal homeostasis by controlling the balance between membrane repair and degradation.

• Zhang, Bao-cun; Nandakumar, Ramya; Reinert, Line S.; Huang, Jinrong; Laustsen, Anders & Gao, Zong-liang [Vis alle 31 forfattere av denne artikkelen] (2020). STEEP mediates STING ER exit and activation of signaling. Nature Immunology. ISSN 1529-2908. 21(8), s. 868–879. doi: 10.1038/s41590-020-0730-5. Fulltekst i vitenarkiv
• Agudo-Canalejo, Jaime; Schultz, Sebastian; Chino, Haruka; Migliano, Simona; Saito, Chieko & Koyama-Honda, Ikuko [Vis alle 11 forfattere av denne artikkelen] (2020). Wetting regulates autophagy of phase-separated compartments and the cytosol. Nature. ISSN 0028-0836. s. 1–5. doi: 10.1038/s41586-020-2992-3. Fulltekst i vitenarkiv
• Sneeggen, Marte; Schink, Kay Oliver & Stenmark, Harald (2019). Tumor suppression by control of matrix metalloproteinase recycling. Molecular and Cellular Oncology (MCO). 6(6), s. 1–3. doi: 10.1080/23723556.2019.1646606. Fulltekst i vitenarkiv Vis sammendrag

  Secretion of matrix metalloproteinases (MMPs) enables cancer cells to degrade extracellular matrix, thus promoting tumor invasion and metastasis. We have recently found that the endosomal protein WDFY2 serves as a gatekeeper for MMP recycling from endosomes and that deletion of WDFY2, which is frequently lost in metastatic cancers, causes increased matrix degradation and cell invasion.

• Skjesol, Astrid; Yurchenko, Mariya; Bösl, Korbinian; Gravastrand, Caroline S.; Nilsen, Kaja Elisabeth & Grøvdal, Lene Melsæther [Vis alle 20 forfattere av denne artikkelen] (2019). The TLR4 adaptor TRAM controls the phagocytosis of Gram-negative bacteria by interacting with the Rab11-family interacting protein 2. PLoS Pathogens. ISSN 1553-7366. 15:e1007684(3), s. 1–30. doi: 10.1371/journal.ppat.1007684. Fulltekst i vitenarkiv Vis sammendrag

  Phagocytosis is a complex process that eliminates microbes and is performed by specialised cells such as macrophages. Toll-like receptor 4 (TLR4) is expressed on the surface of macrophages and recognizes Gram-negative bacteria. Moreover, TLR4 has been suggested to play a role in the phagocytosis of Gram-negative bacteria, but the mechanisms remain unclear. Here we have used primary human macrophages and engineered THP-1 monocytes to show that the TLR4 sorting adapter, TRAM, is instrumental for phagocytosis of Escherichia coli as well as Staphylococcus aureus. We find that TRAM forms a complex with Rab11 family interacting protein 2 (FIP2) that is recruited to the phagocytic cups of E. coli. This promotes activation of the actin-regulatory GTPases Rac1 and Cdc42. Our results show that FIP2 guided TRAM recruitment orchestrates actin remodelling and IRF3 activation, two events that are both required for phagocytosis of Gram-negative bacteria.

• Palomo-Guerrero, Marta; Fadó, Rut; Casas, Maria; Pérez-Montero, Marta; Baena, Miguel & Helmer, Patrick O. [Vis alle 13 forfattere av denne artikkelen] (2019). Sensing of nutrients by CPT1C regulates late endosome/lysosome anterograde transport and axon growth. eLIFE. 8:e51063, s. 1–26. doi: 10.7554/eLife.51063. Fulltekst i vitenarkiv Vis sammendrag

  Anterograde transport of late endosomes or lysosomes (LE/Lys) is crucial for proper axon growth. However, the role of energetic nutrients has been poorly explored. Malonyl-CoA is a precursor of fatty acids, and its intracellular levels highly fluctuate depending on glucose availability or the energy sensor AMP-activated protein kinase (AMPK). We demonstrate in HeLa cells that carnitine palmitoyltransferase 1C (CPT1C) senses malonyl-CoA and enhances LE/Lys anterograde transport by interacting with the endoplasmic reticulum protein protrudin and facilitating the transfer of Kinesin-1 from protrudin to LE/Lys. In cultured mouse cortical neurons, glucose deprivation, pharmacological activation of AMPK or inhibition of malonyl-CoA synthesis decreases LE/Lys abundance at the axon terminal, and shortens axon length in a CPT1C-dependent manner. These results identify CPT1C as a new regulator of anterograde LE/Lys transport in response to malonyl-CoA changes, and give insight into how axon growth is controlled by nutrients.

• Vietri, Marina; Radulovic, Maja & Stenmark, Harald (2019). The many functions of ESCRTs. Nature reviews. Molecular cell biology. ISSN 1471-0072. 21, s. 25–42. doi: 10.1038/s41580-019-0177-4. Fulltekst i vitenarkiv Vis sammendrag

  Cellular membranes can form two principally different involutions, which either exclude or contain cytosol. The ‘classical’ budding reactions, such as those occurring during endocytosis or formation of exocytic vesicles, involve proteins that assemble on the cytosol-excluding face of the bud neck. Inverse membrane involution occurs in a wide range of cellular processes, supporting cytokinesis, endosome maturation, autophagy, membrane repair and many other processes. Such inverse membrane remodelling is mediated by a heteromultimeric protein machinery known as endosomal sorting complex required for transport (ESCRT). ESCRT proteins assemble on the cytosolic (or nucleoplasmic) face of the neck of the forming involution and cooperate with the ATPase VPS4 to drive membrane scission or sealing. Here, we review similarities and differences of various ESCRT-dependent processes, with special emphasis on mechanisms of ESCRT recruitment.

• Scorrano, Luca; Matteis, Maria Antonietta De; Emr, Scott; Giordano, Francesca; Hajnóczky, György & Kornmann, Benoît [Vis alle 15 forfattere av denne artikkelen] (2019). Coming together to define membrane contact sites. Nature Communications. 10:1287, s. 1–11. doi: 10.1038/s41467-019-09253-3. Fulltekst i vitenarkiv Vis sammendrag

  Close proximities between organelles have been described for decades. However, only recently a specific field dealing with organelle communication at membrane contact sites has gained wide acceptance, attracting scientists from multiple areas of cell biology. The diversity of approaches warrants a unified vocabulary for the field. Such definitions would facilitate laying the foundations of this field, streamlining communication and resolving semantic controversies. This opinion, written by a panel of experts in the field, aims to provide this burgeoning area with guidelines for the experimental definition and analysis of contact sites. It also includes suggestions on how to operationally and tractably measure and analyze them with the hope of ultimately facilitating knowledge production and dissemination within and outside the field of contact-site research.

• Zhen, Yan; Spangenberg, Helene; Munson, Michael Joseph; Brech, Andreas; Schink, Kay Oliver & Tan, Kia Wee [Vis alle 13 forfattere av denne artikkelen] (2019). ESCRT-mediated phagophore sealing during mitophagy. Autophagy. ISSN 1554-8627. s. 1–16. doi: 10.1080/15548627.2019.1639301. Fulltekst i vitenarkiv Vis sammendrag

  Inactivation of the endosomal sorting complex required for transport (ESCRT) machinery has been reported to cause autophagic defects, but the exact functions of ESCRT proteins in macroautophagy/autophagy remain incompletely understood. Using live-cell fluorescence microscopy we found that the filament-forming ESCRT-III subunit CHMP4B was recruited transiently to nascent autophagosomes during starvation-induced autophagy and mitophagy, with residence times of about 1 and 2 min, respectively. Correlative light microscopy and electron tomography revealed CHMP4B recruitment at a late step in mitophagosome formation. The autophagosomal dwell time of CHMP4B was strongly increased by depletion of the regulatory ESCRT-III subunit CHMP2A. Using a novel optogenetic closure assay we observed that depletion of CHMP2A inhibited phagophore sealing during mitophagy. Consistent with this, depletion of CHMP2A and other ESCRT-III subunits inhibited both PRKN/PARKIN-dependent and -independent mitophagy. We conclude that the ESCRT machinery mediates phagophore closure, and that this is essential for mitophagic flux.

• Sneeggen, Marte; Pedersen, Nina Marie; Campsteijn, Coen; Haugsten, Ellen Margrethe; Stenmark, Harald & Schink, Kay Oliver (2019). WDFY2 restrains matrix metalloproteinase secretion and cell invasion by controlling VAMP3-dependent recycling. Nature Communications. 10(1), s. 1–20. doi: 10.1038/s41467-019-10794-w. Fulltekst i vitenarkiv Vis sammendrag

  Cancer cells secrete matrix metalloproteinases to remodel the extracellular matrix, which enables them to overcome tissue barriers and form metastases. The membrane-bound matrix metalloproteinase MT1-MMP (MMP14) is internalized by endocytosis and recycled in endosomal compartments. It is largely unknown how endosomal sorting and recycling of MT1-MMP are controlled. Here, we show that the endosomal protein WDFY2 controls the recycling of MT1-MMP. WDFY2 localizes to endosomal tubules by binding to membranes enriched in phosphatidylinositol 3-phosphate (PtdIns3P). We identify the v-SNARE VAMP3 as an interaction partner of WDFY2. WDFY2 knockout causes a strong redistribution of VAMP3 into small vesicles near the plasma membrane. This is accompanied by increased, VAMP3-dependent secretion of MT1-MMP, enhanced degradation of extracellular matrix, and increased cell invasion. WDFY2 is frequently lost in metastatic cancers, most predominantly in ovarian and prostate cancer. We propose that WDFY2 acts as a tumor suppressor by serving as a gatekeeper for VAMP3 recycling.

• Lie-Jensen, Anette; Ivanauskiene, Kristina; Malerød, Lene; Jain, Ashish; Tan, Kia Wee & Lærdahl, Jon Kristen [Vis alle 9 forfattere av denne artikkelen] (2019). Centralspindlin Recruits ALIX to the Midbody during Cytokinetic Abscission in Drosophila via a Mechanism Analogous to Virus Budding. Current Biology. ISSN 0960-9822. 29(20), s. 3538–3548.e7. doi: 10.1016/j.cub.2019.09.025. Fulltekst i vitenarkiv
• Goodridge, Jodie; Jacobs, Benedikt Marcel; Sætersmoen, Michelle Lu; Clement, Dennis; Hammer, Quirin & Clancy, Trevor [Vis alle 24 forfattere av denne artikkelen] (2019). Remodeling of secretory lysosomes during education tunes functional potential in NK cells. Nature Communications. 10:14, s. 1–15. doi: 10.1038/s41467-019-08384-x. Fulltekst i vitenarkiv Vis sammendrag

  Inhibitory signaling during natural killer (NK) cell education translates into increased responsiveness to activation; however, the intracellular mechanism for functional tuning by inhibitory receptors remains unclear. Secretory lysosomes are part of the acidic lysosomal compartment that mediates intracellular signalling in several cell types. Here we show that educated NK cells expressing self-MHC specific inhibitory killer cell immunoglobulin-like receptors (KIR) accumulate granzyme B in dense-core secretory lysosomes that converge close to the centrosome. This discrete morphological phenotype is independent of transcriptional programs that regulate effector function, metabolism and lysosomal biogenesis. Meanwhile, interference of signaling from acidic Ca2+ stores in primary NK cells reduces target-specific Ca2+-flux, degranulation and cytokine production. Furthermore, inhibition of PI(3,5)P2 synthesis, or genetic silencing of the PI(3,5)P2-regulated lysosomal Ca2+-channel TRPML1, leads to increased granzyme B and enhanced functional potential, thereby mimicking the educated state. These results indicate an intrinsic role for lysosomal remodeling in NK cell education.

• Mejlvang, Jakob; Olsvik, Hallvard Lauritz; Svenning, Steingrim; Bruun, Jack-Ansgar; Abudu, Yakubu Princely & Larsen, Kenneth Bowitz [Vis alle 12 forfattere av denne artikkelen] (2018). Starvation induces rapid degradation of selective autophagy receptors by endosomal microautophagy. Journal of Cell Biology. ISSN 0021-9525. 217(10), s. 3640–3655. doi: 10.1083/jcb.201711002. Fulltekst i vitenarkiv Vis sammendrag

  It is not clear to what extent starvation-induced autophagy affects the proteome on a global scale and whether it is selective. In this study, we report based on quantitative proteomics that cells during the first 4 h of acute starvation elicit lysosomal degradation of up to 2–3% of the proteome. The most significant changes are caused by an immediate autophagic response elicited by shortage of amino acids but executed independently of mechanistic target of rapamycin and macroautophagy. Intriguingly, the autophagy receptors p62/SQSTM1, NBR1, TAX1BP1, NDP52, and NCOA4 are among the most efficiently degraded substrates. Already 1 h after induction of starvation, they are rapidly degraded by a process that selectively delivers autophagy receptors to vesicles inside late endosomes/multivesicular bodies depending on the endosomal sorting complex required for transport III (ESCRT-III). Our data support a model in which amino acid deprivation elicits endocytosis of specific membrane receptors, induction of macroautophagy, and rapid degradation of autophagy receptors by endosomal microautophagy.

• Wenzel, Eva; Schultz, Sebastian; Schink, Kay Oliver; Pedersen, Nina Marie; Nähse, Viola & Carlson, Andreas [Vis alle 9 forfattere av denne artikkelen] (2018). Concerted ESCRT and clathrin recruitment waves define the timing and morphology of intraluminal vesicle formation. Nature Communications. 9(2932), s. 1–18. doi: 10.1038/s41467-018-05345-8. Fulltekst i vitenarkiv Vis sammendrag

  The endosomal sorting complex required for transport (ESCRT) machinery mediates cargo sorting, membrane deformation and membrane scission on the surface of endosomes, generating intraluminal vesicles (ILVs) to degrade signaling receptors. By live-cell imaging of individual endosomes in human cells, we find that ESCRT proteins are recruited in a repetitive pattern: ESCRT-0 and -I show a gradual and linear recruitment and dissociation, whereas ESCRT-III and its regulatory ATPase VPS4 display fast and transient dynamics. Electron microscopy shows that ILVs are formed consecutively, starting immediately after endocytic uptake of cargo proteins and correlating with the repeated ESCRT recruitment waves, unraveling the timing of ILV formation. Clathrin, recruited by ESCRT-0, is required for timely ESCRT-0 dissociation, efficient ILV formation, correct ILV size and cargo degradation. Thus, cargo sorting and ILV formation occur by concerted, coordinated and repetitive recruitment waves of individual ESCRT subcomplexes and are controlled by clathrin.

• Radulovic, Maja & Stenmark, Harald (2018). ESCRTs in membrane sealing. Biochemical Society Transactions. ISSN 0300-5127. 46(4), s. 773–778. doi: 10.1042/BST20170435. Fulltekst i vitenarkiv Vis sammendrag

  The multisubunit endosomal sorting complex required for transport (ESCRT) machinery is a key regulator of cellular membrane dynamics. Initially characterized in the budding yeast Saccharomyces cerevisiae for its involvement in cargo sorting to the vacuole, the yeast lysosome, this protein complex has emerged over the past decade as a driver for diverse membrane remodeling processes. Its pleiotropic functional connection is mirrored in numerous cellular processes, such as cytokinetic abscission during the final step of cell division, nuclear pore quality control, nuclear envelope sealing and repair, plasma membrane repair, vesicle shedding from the plasma membrane, viral budding, and axonal pruning. Common to all the processes regulated by the ESCRT machinery is their assembly on the cytosolic side of the respective membrane to stabilize concave membranes, budding, and scission of narrow membrane necks away from the cytosol. Thus, this machinery has evolved to perform many functions in membrane dynamics, and given its importance, it is not surprising that the dysfunctional ESCRT machinery has been implicated in several diseases. In this mini-review, we summarize the role of ESCRT proteins in membrane deformation specifically during membrane sealing and repair.

• Olsvik, Hallvard Lauritz; Svenning, Steingrim; Abudu, Yakubu Princely; Brech, Andreas; Stenmark, Harald & Johansen, Terje [Vis alle 7 forfattere av denne artikkelen] (2018). Endosomal microautophagy is an integrated part of the autophagic response to amino acid starvation. Autophagy. ISSN 1554-8627. 15(1), s. 182–183. doi: 10.1080/15548627.2018.1532265. Fulltekst i vitenarkiv Vis sammendrag

  Starvation is a fundamental type of stress naturally occurring in biological systems. All organisms have therefore evolved different safeguard mechanisms to cope with deficiencies in various types of nutrients. Cells, from yeast to humans, typically respond to amino acid starvation by initiating degradation of cellular components by inducing autophagy. This degradation releases metabolic building blocks to sustain essential core cellular processes. Increasing evidence indicates that starvation-induced autophagy also acts to prepare cells for prolonged starvation by degrading key regulators of different cellular processes. In a recent study, we found that within the first hours of amino acid starvation cells elicit an autophagic response causing rapid degradation of specific proteins. The response is executed independently of both MTOR and canonical macroautophagy. Based on RNAi-mediated knockdown of essential components of the Endosomal Sorting Complex Required for Transport (ESCRT) machinery and electron microscopy we conclude that the response relies on some sort of endosomal microautophagy, hence vesicle budding into endosomes. Substantiated by the different substrates that are selectively degraded by this novel pathway we propose that the response predominantly acts to prepare cells for prolonged starvation. Intriguingly, this includes shutting down selective macroautophagy in preparation for a massive induction of bulk macroautophagy.

• Vietri, Marina & Stenmark, Harald (2018). Orchestrating Nuclear Envelope Sealing during Mitosis. Developmental Cell. ISSN 1534-5807. 47(5), s. 541–542. doi: 10.1016/j.devcel.2018.11.020. Fulltekst i vitenarkiv
• Radulovic, Maja; Schink, Kay Oliver; Wenzel, Eva; Nähse, Viola; Bongiovanni, Antonino & Lafont, Frank [Vis alle 7 forfattere av denne artikkelen] (2018). ESCRT-mediated lysosome repair precedes lysophagy and promotes cell survival. EMBO Journal. ISSN 0261-4189. 37:e00753, s. 1–15. doi: 10.15252/embj.201899753. Fulltekst i vitenarkiv Vis sammendrag

  Although lysosomes perform a number of essential cellular functions, damaged lysosomes represent a potential hazard to the cell. Such lysosomes are therefore engulfed by autophagic membranes in the process known as lysophagy, which is initiated by recognition of luminal glycoprotein domains by cytosolic lectins such as Galectin‐3. Here, we show that, under various conditions that cause injury to the lysosome membrane, components of the endosomal sorting complex required for transport (ESCRT)‐I, ESCRT‐II, and ESCRT‐III are recruited. This recruitment occurs before that of Galectin‐3 and the lysophagy machinery. Subunits of the ESCRT‐III complex show a particularly prominent recruitment, which depends on the ESCRT‐I component TSG101 and the TSG101‐ and ESCRT‐III‐binding protein ALIX. Interference with ESCRT recruitment abolishes lysosome repair and causes otherwise reversible lysosome damage to become cell lethal. Vacuoles containing the intracellular pathogen Coxiella burnetii show reversible ESCRT recruitment, and interference with this recruitment reduces intravacuolar bacterial replication. We conclude that the cell is equipped with an endogenous mechanism for lysosome repair which protects against lysosomal damage‐induced cell death but which also provides a potential advantage for intracellular pathogens.

• Malerød, Lene; Borgne, Roland Le; Lie-Jensen, Anette Christensen; Eikenes, Åsmund Husabø; Brech, Andreas & Liestøl, Knut [Vis alle 8 forfattere av denne artikkelen] (2018). Centrosomal ALIX regulates mitotic spindle orientation by modulating astral microtubule dynamics. EMBO Journal. ISSN 0261-4189. 37(13), s. 1–21. doi: 10.15252/embj.201797741. Fulltekst i vitenarkiv
• Thorvaldsen, Tor Espen; Pedersen, Nina Marie; Wenzel, Eva & Stenmark, Harald Alfred (2017). Differential Roles of AXIN1 and AXIN2 in Tankyrase Inhibitor-Induced Formation of Degradasomes and β-Catenin Degradation. PLOS ONE. 12(1). doi: 10.1371/journal.pone.0170508. Fulltekst i vitenarkiv Vis sammendrag

  Inhibition of the tankyrase enzymes (TNKS1 and TNKS2) has recently been shown to induce highly dynamic assemblies of β-catenin destruction complex components known as degradasomes, which promote degradation of β-catenin and reduced Wnt signaling activity in colorectal cancer cells. AXIN1 and AXIN2/Conductin, the rate-limiting factors for the stability and function of endogenous destruction complexes, are stabilized upon TNKS inhibition due to abrogated degradation of AXIN by the proteasome. Since the role of AXIN1 versus AXIN2 as scaffolding proteins in the Wnt signaling pathway still remains incompletely understood, we sought to elucidate their relative contribution in the formation of degradasomes, as these protein assemblies most likely represent the morphological and functional correlates of endogenous β-catenin destruction complexes. In SW480 colorectal cancer cells treated with the tankyrase inhibitor (TNKSi) G007-LK we found that AXIN1 was not required for degradasome formation. In contrast, the formation of degradasomes as well as their capacity to degrade β-catenin were considerably impaired in G007-LK-treated cells depleted of AXIN2. These findings give novel insights into differential functional roles of AXIN1 versus AXIN2 in the β-catenin destruction complex.

• Raiborg, Camilla; Schink, Kay Oliver & Stenmark, Harald Alfred (2017). Suppressing mTORC1 on the lysosome. EMBO Journal. ISSN 0261-4189. 36(13), s. 1803–1991. doi: 10.15252/embj.201797469. Fulltekst i vitenarkiv
• Hong, Zhi; Pedersen, Nina Marie; Ling, Wang; Torgersen, Maria Lyngaas; Stenmark, Harald Alfred & Raiborg, Camilla (2017). PtdIns3P controls mTORC1 signaling through lysosomal positioning. Journal of Cell Biology. ISSN 0021-9525. 216(12), s. 4217–4233. doi: 10.1083/jcb.201611073. Fulltekst i vitenarkiv
• O'Farrell, Fergal; Lobert, Viola; Sneeggen, Marte; Jain, Ashish; Katheder, Nadja Sandra & Wenzel, Eva [Vis alle 11 forfattere av denne artikkelen] (2017). Class III phosphatidylinositol-3-OH kinase controls epithelial integrity through endosomal LKB1 regulation. Nature Cell Biology. ISSN 1465-7392. 19(12), s. 1412–1423. doi: 10.1038/ncb3631. Fulltekst i vitenarkiv
• Katheder, Nadja Sandra; Khezri, Rojyar; O'Farrell, Fergal; Schultz, Sebastian; Jain, Ashish & Rahman, Mohammed Mahidur [Vis alle 14 forfattere av denne artikkelen] (2017). Microenvironmental autophagy promotes tumour growth. Nature. ISSN 0028-0836. 541(7637), s. 417–420. doi: 10.1038/nature20815. Fulltekst i vitenarkiv
• Christ, Liliane Florence; Raiborg, Camilla; Wenzel, Eva; Campsteijn, Coen & Stenmark, Harald Alfred (2017). Cellular Functions and Molecular Mechanisms of the ESCRT Membrane-Scission Machinery. TIBS -Trends in Biochemical Sciences. Regular ed.. ISSN 0968-0004. 42(1), s. 42–56. doi: 10.1016/j.tibs.2016.08.016. Fulltekst i vitenarkiv
• O'Farrell, Fergal; Lobert, Viola; Sneeggen, Marte; Jain, Ashish; Katheder, Nadja Sandra & Wenzel, Eva [Vis alle 11 forfattere av denne artikkelen] (2017). Class III phosphatidylinositol-3-OH kinase controls epithelial integrity through endosomal LKB1 regulation. Nature Cell Biology. ISSN 1465-7392. 19, s. 1412–1423. doi: 10.1038/ncb3631. Fulltekst i vitenarkiv
• Nahse, Viola; Christ, Liliane Florence; Stenmark, Harald Alfred & Campsteijn, Coen (2017). The Abscission Checkpoint: Making It to the Final Cut. Trends in Cell Biology. ISSN 0962-8924. 27(1), s. 1–11. doi: 10.1016/j.tcb.2016.10.001. Fulltekst i vitenarkiv
• Sundvold, Hilde; Gjerstad, Vibeke Sundvold; Malerød-Fjeld, Helle; Haglund, Kaisa; Stenmark, Harald Alfred & Malerød, Lene (2016). Arv1 promotes cell division by recruiting IQGAP1 and myosin to the cleavage furrow. Cell Cycle. ISSN 1538-4101. 15(5), s. 628–643. doi: 10.1080/15384101.2016.1146834. Fulltekst i vitenarkiv
• Christ, Liliane Florence; Wenzel, Eva; Liestøl, Knut; Raiborg, Camilla; Campsteijn, Coen & Stenmark, Harald Alfred (2016). ALIX and ESCRT-I/II function as parallel ESCRT-III recruiters in cytokinetic abscission. Journal of Cell Biology. ISSN 0021-9525. 212(5), s. 499–513. doi: 10.1083/jcb.201507009. Fulltekst i vitenarkiv
• Mamińska, Agnieszka; Bartosik, Anna; Banach-Orlowska, Magdalena; Pilecka, Iwona; Jastrzębski, Kamil & Zdżalik-Bielecka, Daria [Vis alle 19 forfattere av denne artikkelen] (2016). ESCRT proteins restrict constitutive NF-κB signaling by trafficking cytokine receptors. Science Signaling. ISSN 1945-0877. 9(411). doi: 10.1126/scisignal.aad0848. Fulltekst i vitenarkiv
• Campsteijn, Coen; Vietri, Marina & Stenmark, Harald Alfred (2016). Novel ESCRT functions in cell biology: Spiraling out of control? Current Opinion in Cell Biology. ISSN 0955-0674. 41, s. 1–8. doi: 10.1016/j.ceb.2016.03.008. Fulltekst i vitenarkiv
• Pedersen, Nina Marie; Thorvaldsen, Tor Espen; Schultz, Sebastian; Wenzel, Eva & Stenmark, Harald Alfred (2016). Formation of tankyrase inhibitor-induced degradasomes requires proteasome activity. PLOS ONE. 11(8). doi: 10.1371/journal.pone.0160507. Fulltekst i vitenarkiv Vis sammendrag

  In canonical Wnt signaling, the protein levels of the key signaling mediator β-catenin are under tight regulation by the multimeric destruction complex that mediates proteasomal degradation of β-catenin. In colorectal cancer, destruction complex activity is often compromised due to mutations in the multifunctional scaffolding protein Adenomatous Polyposis Coli (APC), leading to a stabilization of β-catenin. Recently, tankyrase inhibitors (TNKSi), a novel class of small molecule inhibitors, were shown to re-establish a functional destruction complex in APC-mutant cancer cell lines by stabilizing AXIN1/2, whose protein levels are usually kept low via poly(ADP-ribosyl)ation by the tankyrase enzymes (TNKS1/2). Surprisingly, we found that for the formation of the morphological correlates of destruction complexes, called degradasomes, functional proteasomes are required. In addition we found that AXIN2 is strongly upregulated after 6 h of TNKS inhibition. The proteasome inhibitor MG132 counteracted TNKSi-induced degradasome formation and AXIN2 stabilization, and this was accompanied by reduced transcription of AXIN2. Mechanistically we could implicate the transcription factor FoxM1 in this process, which was recently shown to be a transcriptional activator of AXIN2. We observed a substantial reduction in TNKSi-induced stabilization of AXIN2 after siRNA-mediated depletion of FoxM1 and found that proteasome inhibition reduced the active (phosphorylated) fraction of FoxM1. This can explain the decreased protein levels of AXIN2 after MG132 treatment. Our findings have implications for the design of in vitro studies on the destruction complex and for clinical applications of TNKSi.

• Raiborg, Camilla; Wenzel, Eva; Pedersen, Nina Marie & Stenmark, Harald Alfred (2016). Phosphoinositides in membrane contact sites. Biochemical Society Transactions. ISSN 0300-5127. 44(2), s. 425–430. doi: 10.1042/BST20150190. Fulltekst i vitenarkiv
• Raiborg, Camilla; Wenzel, Eva; Pedersen, Nina Marie & Stenmark, Harald Alfred (2016). ER-endosome contact sites in endosome positioning and protrusion outgrowth. Biochemical Society Transactions. ISSN 0300-5127. 44(2), s. 441–446. doi: 10.1042/BST20150246. Fulltekst i vitenarkiv
• Raiborg, Camilla & Stenmark, Harald Alfred (2016). Plasma membrane repairs by small GTPase Rab3a. Journal of Cell Biology. ISSN 0021-9525. 213(6), s. 613–615. doi: 10.1083/jcb.201606006. Fulltekst i vitenarkiv
• Vietri, Marina; Stenmark, Harald Alfred & Campsteijn, Coen (2016). Closing a gap in the nuclear envelope. Current Opinion in Cell Biology. ISSN 0955-0674. 40, s. 90–97. doi: 10.1016/j.ceb.2016.03.001. Fulltekst i vitenarkiv
• Schink, Kay Oliver; Tan, Kia Wee & Stenmark, Harald Alfred (2016). Phosphoinositides in Control of Membrane Dynamics. Annual Review of Cell and Developmental Biology. ISSN 1081-0706. 32, s. 143–171. doi: 10.1146/annurev-cellbio-111315-125349. Fulltekst i vitenarkiv
• Raiborg, Camilla; Wenzel, Eva & Stenmark, Harald Alfred (2015). ER-endosome contact sites: Molecular compositions and functions. EMBO Journal. ISSN 0261-4189. 34(14), s. 1848–1858. doi: 10.15252/embj.201591481. Fulltekst i vitenarkiv
• Eikenes, Åsmund Husabø; Malerød, Lene; Christensen, Anette Lie; Steen, Chloe Beate; Mathieu, Juliette & Nezis, Ioannis P [Vis alle 10 forfattere av denne artikkelen] (2015). ALIX and ESCRT-III Coordinately Control Cytokinetic Abscission during Germline Stem Cell Division In Vivo. PLoS Genetics. ISSN 1553-7390. 11(1). doi: 10.1371/journal.pgen.1004904. Fulltekst i vitenarkiv
• Vietri, Marina; Schink, Kay Oliver; Campsteijn, Coen; Wegner, Catherine E Sem; Schultz, Sebastian & Christ, Liliane Florence [Vis alle 10 forfattere av denne artikkelen] (2015). Spastin and ESCRT-III coordinate mitotic spindle disassembly and nuclear envelope sealing. Nature. ISSN 0028-0836. 522(7555), s. 231–235. doi: 10.1038/nature14408. Fulltekst i vitenarkiv
• Raiborg, Camilla & Stenmark, Harald (2015). An ER clamp for endosome fission. EMBO Journal. ISSN 0261-4189. 34(2), s. 136–137. doi: 10.15252/embj.201490707. Fulltekst i vitenarkiv
• Raiborg, Camilla; Wenzel, Eva; Pedersen, Nina Marie; Olsvik, Hallvard Lauritz; Schink, Kay Oliver & Schultz, Sebastian [Vis alle 12 forfattere av denne artikkelen] (2015). Repeated ER-endosome contacts promote endosome translocation and neurite outgrowth. Nature. ISSN 0028-0836. 520(7546), s. 234–238. doi: 10.1038/nature14359. Fulltekst i vitenarkiv
• Eikenes, Åsmund Husabø; Malerød, Lene; Christensen, Anette Lie; Wegner, Catherine E Sem; Brech, Andreas & Liestøl, Knut [Vis alle 8 forfattere av denne artikkelen] (2015). Src64 controls a novel actin network required for proper ring canal formation in the drosophila male germline. Development. ISSN 0950-1991. 142(23), s. 4107–4118. doi: 10.1242/dev.124370. Fulltekst i vitenarkiv Vis sammendrag

  In many organisms, germ cells develop as cysts in which cells are interconnected via ring canals (RCs) as a result of incomplete cytokinesis. However, the molecular mechanisms of incomplete cytokinesis remain poorly understood. Here, we address the role of tyrosine phosphorylation of RCs in the Drosophila male germline. We uncover a hierarchy of tyrosine phosphorylation within germline cysts that positively correlates with RC age. The kinase Src64 is responsible for mediating RC tyrosine phosphorylation, and loss of Src64 causes a reduction in RC diameter within germline cysts. Mechanistically, we show that Src64 controls an actin network around the RCs that depends on Abl and the Rac/SCAR/Arp2/3 pathway. The actin network around RCs is required for correct RC diameter in cysts of developing germ cells. We also identify that Src64 is required for proper germ cell differentiation in the Drosophila male germline independent of its role in RC regulation. In summary, we report that Src64 controls actin dynamics to mediate proper RC formation during incomplete cytokinesis during germline cyst development in vivo.

• Thorvaldsen, Tor Espen; Pedersen, Nina Marie; Wenzel, Eva; Schultz, Sebastian; Brech, Andreas & Liestøl, Knut [Vis alle 9 forfattere av denne artikkelen] (2015). Structure, dynamics, and functionality of tankyrase inhibitor-induced degradasomes. Molecular Cancer Research. ISSN 1541-7786. 13(11), s. 1487–1501. doi: 10.1158/1541-7786.MCR-15-0125. Fulltekst i vitenarkiv

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• Stenseth, Nils Christian; Andreassen, Karin Marie; Danielsen, Anne; Helgaker, Trygve; Jansen, Eystein & Moser, Edvard Ingjald [Vis alle 11 forfattere av denne artikkelen] (2022). Grunnforskningen er truet. Fulltekst i vitenarkiv
• Beckwith, Marianne Sandvold; Beckwith, Kai Sandvold; Ullmann, Sindre; Sætra, Ragnhild Sofie Ragnhildstveit; Marstad, Anne & Kim, Haelin [Vis alle 12 forfattere av denne artikkelen] (2020). Plasma membrane damage causes NLRP3 activation and pyroptosis during Mycobacterium tuberculosis infection. Fulltekst i vitenarkiv
• Zhang, Bao-cun; Nandakumar, Ramya; Reinert, Line S.; Huang, Jinrong; Laustsen, Anders & Gao, Zong-liang [Vis alle 31 forfattere av denne artikkelen] (2020). Author Correction: STEEP mediates STING ER exit and activation of signaling (Nature Immunology, (2020), 21, 8, (868-879), 10.1038/s41590-020-0730-5). Nature Immunology. ISSN 1529-2908. 21(11), s. 1468–1469. doi: 10.1038/s41590-020-0803-5. Fulltekst i vitenarkiv
• Stenmark, Harald Alfred (2019). Lysosome repair in cell survival and host-pathogen interactions. Fulltekst i vitenarkiv
• Flo, Trude Helen; Beckwith, Kai Sandvold; Beckwith, Marianne Sandvold; Ullmann, Sindre; Sætra, Ragnhild Sofie Ragnhildstveit & Strand, Trine Aakvik [Vis alle 9 forfattere av denne artikkelen] (2019). Balancing life and death in mycobacterium-infected macrophages. Fulltekst i vitenarkiv
• Flo, Trude Helen; Beckwith, Kai Sandvold; Beckwith, Marianne Sandvold; Ullmann, Sindre; Sætra, Ragnhild Sofie Ragnhildstveit & Marstad, Anne [Vis alle 9 forfattere av denne artikkelen] (2019). Single-cell dynamics of NLRP3 inflammasome activation and pyroptosis during Mycobacterium tuberculosis infection of human macrophages. Fulltekst i vitenarkiv
• Skjesol, Astrid; Yurchenko, Mariya; Bösl, Korbinian; Gravastrand, Caroline S.; Nilsen, Kaja Elisabeth & Agliano, Federica [Vis alle 12 forfattere av denne artikkelen] (2019). The TLR4 adaptor TRAM controls phagocytosis of E. coli through FIP2. Fulltekst i vitenarkiv
• Liese, Susanne; Molina, Rossana Virginia Rojas; Wenzel, Eva; Raiborg, Camilla; Stenmark, Harald & Carlson, Andreas (2018). Formation of Coatless Membrane Vesicles. Fulltekst i vitenarkiv
• Grøvdal, Lene Melsæther; Schink, Kay Oliver; Pelka, Karin; Husebye, Harald; Latz, Eicke & Stenmark, Harald Alfred [Vis alle 7 forfattere av denne artikkelen] (2016). Moving Tolls - Novel interactors of TLR9 trafficking. Fulltekst i vitenarkiv
• Grøvdal, Lene Melsæther; Schink, Kay Oliver; Pelka, Karin; Husebye, Harald; Latz, Eicke & Stenmark, Harald Alfred [Vis alle 7 forfattere av denne artikkelen] (2016). Moving Tolls - novel interactors of TLR9 trafficking. Fulltekst i vitenarkiv
• Grøvdal, Lene Melsæther; Schink, Kay Oliver; Pelka, Karin; Husebye, Harald; Latz, Eicke & Stenmark, Harald Alfred [Vis alle 7 forfattere av denne artikkelen] (2015). Moving Tolls - novel interactors of TLR9 trafficking. Fulltekst i vitenarkiv

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