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The SM protein VPS‐45 is required for RAB‐5‐dependent endocytic transport in Caenorhabditis elegans
Author(s) -
GengyoAndo Keiko,
Kuroyanagi Hidehito,
Kobayashi Tetsuo,
Murate Motohide,
Fujimoto Kazushi,
Okabe Shigeo,
Mitani Shohei
Publication year - 2007
Publication title -
embo reports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.584
H-Index - 184
eISSN - 1469-3178
pISSN - 1469-221X
DOI - 10.1038/sj.embor.7400882
Subject(s) - rab , endosome , endocytic cycle , microbiology and biotechnology , biology , caenorhabditis elegans , effector , small gtpase , endocytosis , gtpase , transport protein , receptor , signal transduction , biochemistry , gene , intracellular
Rab5, a small guanosine triphosphatase, is known to regulate the tethering and docking reaction leading to SNARE (soluble N SF attachment protein receptors)‐mediated fusion between endosomes. However, it is uncertain how the signal of the activated Rab5 protein is transduced by its downstream effectors during endosome fusion. Here, we show that the Sec1/Munc18 gene vps‐45 is essential for not only viability and development but also receptor‐mediated and fluid‐phase endocytosis pathways in Caenorhabditis elegans . We found that VPS‐45 interacts with a Rab5 effector, Rabenosyn‐5 (RABS‐5), and the mutants of both vps‐45 and rabs‐5 show similar endocytic phenotypes. In the macrophage‐like cells of vps‐45 and rabs‐5 mutants, aberrantly small endosomes were accumulated, and the endosome fusion stimulated by the mutant RAB‐5 (Q78L) is suppressed by these mutations. Our results indicate that VPS‐45 is a key molecule that functions downstream from RAB‐5, cooperating with RABS‐5, to regulate the dynamics of the endocytic system in multicellular organisms.