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Caenorhabditis elegans Rab escort protein (REP‐1) differently regulates each Rab protein function and localization in a tissue‐dependent manner
Author(s) -
Tanaka Daisuke,
Kameyama Kimihiko,
Okamoto Harumasa,
Doi Motomichi
Publication year - 2008
Publication title -
genes to cells
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.912
H-Index - 115
eISSN - 1365-2443
pISSN - 1356-9597
DOI - 10.1111/j.1365-2443.2008.01232.x
Subject(s) - rab , biology , caenorhabditis elegans , vesicular transport protein , microbiology and biotechnology , prenylation , mutant , transport protein , gtpase , genetics , gene , biochemistry , vesicle , membrane , enzyme
Rab proteins play a critical role in intracellular vesicle trafficking and require post‐translational modification by adding lipids at the C‐terminus for proper functions. This modification is preceded by the formation of a trimeric protein complex with the Rab escort protein (REP) and the Rab geranylgeranyltransferase (RabGGTase). However, the genetic hierarchy among these proteins and the tissue‐specificity of each protein function are not yet clearly understood. Here we identified the Caenorhabditis elegans rep‐1 gene and found that a rep‐1 mutant showed a mild defect in synaptic transmission and defecation behaviors. Genetic analyses using the exocytic Rab mutants rab‐3 or rab‐27 suggested that rep‐1 functions only in the RAB‐27 pathway, and not in the RAB‐3 pathway, for synaptic transmission at neuromuscular junctions. However, the disruption of REP‐1 did not cause defecation defects compared to severe defects in either RAB‐27 or RabGGTase disruption, suggesting that REP‐1 is not essential for RAB‐27 signaling in defection. Some Rab proteins did not physically interact with REP‐1, and localization of these Rab proteins was not severely affected by REP‐1 disruption. These findings suggest that REP‐1 functions are required in specific Rab pathways and in specific tissues, and that some Rab proteins are functionally prenylated without REP‐1.