RRC ID 73639
Author Jiang P, Nishimura T, Sakamaki Y, Itakura E, Hatta T, Natsume T, Mizushima N.
Title The HOPS complex mediates autophagosome-lysosome fusion through interaction with syntaxin 17.
Journal Mol Biol Cell
Abstract Membrane fusion is generally controlled by Rabs, soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs), and tethering complexes. Syntaxin 17 (STX17) was recently identified as the autophagosomal SNARE required for autophagosome-lysosome fusion in mammals and Drosophila. In this study, to better understand the mechanism of autophagosome-lysosome fusion, we searched for STX17-interacting proteins. Immunoprecipitation and mass spectrometry analysis identified vacuolar protein sorting 33A (VPS33A) and VPS16, which are components of the homotypic fusion and protein sorting (HOPS)-tethering complex. We further confirmed that all HOPS components were coprecipitated with STX17. Knockdown of VPS33A, VPS16, or VPS39 blocked autophagic flux and caused accumulation of STX17- and microtubule-associated protein light chain (LC3)-positive autophagosomes. The endocytic pathway was also affected by knockdown of VPS33A, as previously reported, but not by knockdown of STX17. By contrast, ultraviolet irradiation resistance-associated gene (UVRAG), a known HOPS-interacting protein, did not interact with the STX17-HOPS complex and may not be directly involved in autophagosome-lysosome fusion. Collectively these results suggest that, in addition to its well-established function in the endocytic pathway, HOPS promotes autophagosome-lysosome fusion through interaction with STX17.
Volume 25(8)
Pages 1327-37
Published 2014-4-1
DOI 10.1091/mbc.E13-08-0447
PII mbc.E13-08-0447
PMID 24554770
PMC PMC3982997
MeSH Animals Autophagy-Related Proteins Cell Fusion Green Fluorescent Proteins / genetics HEK293 Cells HeLa Cells Humans Intracellular Signaling Peptides and Proteins / genetics Lysosomes / immunology* Membrane Fusion / genetics Membrane Fusion / physiology* Mice Microtubule-Associated Proteins / metabolism Oligopeptides / immunology Phagosomes / immunology* Protein Binding Qa-SNARE Proteins / genetics Qa-SNARE Proteins / metabolism* RNA Interference RNA, Small Interfering Tumor Suppressor Proteins / metabolism Vesicular Transport Proteins / genetics Vesicular Transport Proteins / metabolism*
IF 3.791
DNA material pMXsIP-GFP-VPS33A (RDB19783) pMRXIP-VPS16-GFP (RDB19787)