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Characterization of GAPCenA, a GTPase activating protein for Rab6, part of which associates with the centrosome
Author(s) -
Cuif MarieHélène,
Possmayer Franziska,
Zander Hilke,
Bordes Nicole,
Jollivet Florence,
CouedelCourteille Anne,
JanoueixLerosey Isabelle,
Langsley Gordon,
Bornens Michel,
Goud Bruno
Publication year - 1999
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1093/emboj/18.7.1772
Subject(s) - biology , centrosome , microbiology and biotechnology , gtpase , golgi apparatus , rab , nocodazole , schizosaccharomyces pombe , cytokinesis , microtubule nucleation , cytosol , schizosaccharomyces , small gtpase , saccharomyces cerevisiae , biochemistry , cell cycle , cell division , yeast , cell , signal transduction , cytoskeleton , endoplasmic reticulum , enzyme
The Rab6 GTPase regulates intracellular transport at the level of the Golgi apparatus, probably in a retrograde direction. Here, we report the identification and characterization of a novel human Rab6‐interacting protein named human GAPCenA (for ‘GAP and centrosome‐associated’). Primary sequence analysis indicates that GAPCenA displays similarities, within a central 200 amino acids domain, to both the yeast Rab GTPase activating proteins (GAPs) and to the spindle checkpoint proteins Saccharomyces cerevisiae Bub2p and Schizosaccharomyces pombe Cdc16p. We demonstrate that GAPCenA is indeed a GAP, specifically active in vitro on Rab6 and, to a lesser extent, on Rab4 and Rab2 proteins. Immunofluorescence and cell fractionation experiments showed that GAPCenA is mainly cytosolic but that a minor pool is associated with the centrosome. Moreover, GAPCenA was found to form complexes with cytosolic γ‐tubulin and to play a role in microtubule nucleation. Therefore, GAPCenA may be involved in the coordination of microtubule and Golgi dynamics during the cell cycle.