Dan Liu

• Reis, Jose Gerardo Belem Teles Roque Dos; Jain, Ashish; Liu, Dan; Khezri, Rojyar; Antunes, Marina Manuel Goncalves & Micheli, Sofia [Vis alle 9 forfattere av denne artikkelen] (2025). EyaHOST, a modular genetic system for investigation of intercellular and tumor-host interactions in Drosophila melanogaster. Cell Reports Methods. 5(11), s. 1–16. doi: 10.1016/j.crmeth.2025.101220. Fulltekst i vitenarkiv Vis sammendrag

  Studying intercellular and interorgan interactions in animal models is key to understanding development, physiology, and disease. We introduce EyaHOST, a system for clonal combinatorial loss- and gain-of-function genetics in fluorescently labeled cells under QF2-QUAS eya promoter control. Distinct from mosaic analysis with a repressible cell marker (MARCM), it reserves the use of genome-wide GAL4-UAS tools to manipulate any host tissue. EyaHOST-driven RasV12 overexpression with scribble knockdown recapitulates key cancer features, including systemic catabolic switching and organ wasting. We demonstrate effective tissue-specific manipulation of host compartments, including homotypic epithelial neighbors, immune cells, fat body, and muscle. Organ-specific inhibition of autophagy or stimulation of growth signaling via PTEN knockdown in fat body or muscle prevents cachexia-like wasting. Additionally, tumors trigger caspase-driven apoptosis in the neighboring epithelium, and blocking apoptosis with p35 enhances tumor growth. EyaHOST provides a modular platform to dissect mechanisms of intercellular and interorgan communication under physiological or disease conditions.

• 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.

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