Cumulative research findings support the idea that endocytic trafficking is crucial in regulating receptor signaling and associated diseases. Specifically, strong evidence points to the involvement of sorting nexins (SNXs), particularly SNX1 and SNX2, in the signaling and trafficking of the receptor tyrosine kinase (RTK) MET in colorectal cancer (CRC). Activation of hepatocyte growth factor (HGF) receptor MET is a key driver of CRC progression. In the present study, we utilized human HCT116 CRC cells with SNX1 and SNX2 genes knocked out to demonstrate that their absence leads to a delay in MET entering early endosomes. This delay results in increased phosphorylation of both MET and AKT upon HGF stimulation, while ERK1/2 (extracellular signal-regulated kinases 1 and 2) phosphorylation remains unaffected. Despite these changes, HGF-induced cell proliferation, scattering, and migration remain similar between the parental and the SNX1/2 knockout cells. However, in the absence of SNX1 and SNX2, these cells exhibit increased resistance to TRAIL-induced apoptosis. This research underscores the intricate relationship between intracellular trafficking, receptor signaling, and cellular responses and demonstrates for the first time that the modulation of MET trafficking by SNX1 and SNX2 is critical for receptor signaling that may exacerbate the disease.
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http://dx.doi.org/10.1042/BSR20240182 | DOI Listing |
Proc Natl Acad Sci U S A
August 2024
The University of Queensland, Institute for Molecular Bioscience, St Lucia, QLD 4072, Australia.
Endosomal membrane trafficking is mediated by specific protein coats and formation of actin-rich membrane domains. The Retromer complex coordinates with sorting nexin (SNX) cargo adaptors including SNX27, and the SNX27-Retromer assembly interacts with the Wiskott-Aldrich syndrome protein and SCAR homolog (WASH) complex which nucleates actin filaments establishing the endosomal recycling domain. Crystal structures, modeling, biochemical, and cellular validation reveal how the FAM21 subunit of WASH interacts with both Retromer and SNX27.
View Article and Find Full Text PDFBiosci Rep
June 2024
Department of Pharmacology and Physiology.
Contact (Thousand Oaks)
November 2023
Université Paris Cité, INSERM UMR-S1151, CNRS UMR-S8253, Institut Necker Enfants Malades, Paris, France.
Sorting nexins (SNXs) are a family of membrane-binding proteins known to play a critical role in regulating endocytic pathway sorting and endosomal membrane trafficking. Among them, SNX1 and SNX2 are members of the SNX-BAR subfamily and possess a membrane-curvature domain and a phosphoinositide-binding domain, which enables their stabilization at the phosphatidylinositol-3-phosphate (PI3P)-positive surface of endosomes. While their binding to PI3P-positive platforms facilitates interaction with endosomal partners and stabilization at the endosomal membrane, their SNX-BAR region is pivotal for generating membrane tubulation from endosomal compartments.
View Article and Find Full Text PDFLife Sci Alliance
March 2023
Université Paris Cité, INSERM UMR-S1151, CNRS UMR-S8253, Institut Necker Enfants Malades, Paris, France
Nutrient deprivation ("starvation") is a major catabolic stress faced by mammalian cells in both pathological and physiological situations. Starvation induces autophagosome biogenesis in the immediate vicinity of ER and leads to lysosome spatial repositioning, but little is known about the consequences of nutritional stress on endosomes. Here, we report that starvation induces tethering of endosomal tubules to ER subregions, fostering autophagosome assembly.
View Article and Find Full Text PDFCell Mol Life Sci
May 2022
Laboratory of Cell Biology, International Institute of Molecular and Cell Biology, Warsaw, Poland.
AXL, a TAM receptor tyrosine kinase (RTK), and its ligand growth arrest-specific 6 (GAS6) are implicated in cancer metastasis and drug resistance, and cellular entry of viruses. Given this, AXL is an attractive therapeutic target, and its inhibitors are being tested in cancer and COVID-19 clinical trials. Still, astonishingly little is known about intracellular mechanisms that control its function.
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