RRC ID 21502
Author Chotard L, Mishra AK, Sylvain MA, Tuck S, Lambright DG, Rocheleau CE.
Title TBC-2 regulates RAB-5/RAB-7-mediated endosomal trafficking in Caenorhabditis elegans.
Journal Mol Biol Cell
Abstract During endosome maturation the early endosomal Rab5 GTPase is replaced with the late endosomal Rab7 GTPase. It has been proposed that active Rab5 can recruit and activate Rab7, which in turn could inactivate and remove Rab5. However, many of the Rab5 and Rab7 regulators that mediate endosome maturation are not known. Here, we identify Caenorhabditis elegans TBC-2, a conserved putative Rab GTPase-activating protein (GAP), as a regulator of endosome to lysosome trafficking in several tissues. We show that tbc-2 mutant animals accumulate enormous RAB-7-positive late endosomes in the intestine containing refractile material. RAB-5, RAB-7, and components of the homotypic fusion and vacuole protein sorting (HOPS) complex, a RAB-7 effector/putative guanine nucleotide exchange factor (GEF), are required for the tbc-2(-) intestinal phenotype. Expression of activated RAB-5 Q78L in the intestine phenocopies the tbc-2(-) large late endosome phenotype in a RAB-7 and HOPS complex-dependent manner. TBC-2 requires the catalytic arginine-finger for function in vivo and displays the strongest GAP activity on RAB-5 in vitro. However, TBC-2 colocalizes primarily with RAB-7 on late endosomes and requires RAB-7 for membrane localization. Our data suggest that TBC-2 functions on late endosomes to inactivate RAB-5 during endosome maturation.
Volume 21(13)
Pages 2285-96
Published 2010-7-1
DOI 10.1091/mbc.e09-11-0947
PII E09-11-0947
PMID 20462958
PMC PMC2893991
MeSH Amino Acid Sequence Animals Caenorhabditis elegans / cytology Caenorhabditis elegans / metabolism* Caenorhabditis elegans Proteins / genetics Caenorhabditis elegans Proteins / metabolism* Endosomes / metabolism* GTPase-Activating Proteins Humans Molecular Sequence Data RNA Interference Recombinant Fusion Proteins / genetics Recombinant Fusion Proteins / metabolism rab GTP-Binding Proteins / genetics rab GTP-Binding Proteins / metabolism* rab5 GTP-Binding Proteins / genetics rab5 GTP-Binding Proteins / metabolism* rab7 GTP-Binding Proteins
IF 3.791
Times Cited 49
C.elegans tm2241