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ArfGAP1 Activity and COPI Vesicle Biogenesis
Author(s) -
Beck Rainer,
Adolf Frank,
Weimer Carolin,
Bruegger Britta,
Wieland Felix T.
Publication year - 2009
Publication title -
traffic
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.677
H-Index - 130
eISSN - 1600-0854
pISSN - 1398-9219
DOI - 10.1111/j.1600-0854.2008.00865.x
Subject(s) - copi , vesicle , copii , biology , golgi apparatus , microbiology and biotechnology , biogenesis , adp ribosylation factor , biochemistry , secretory pathway , endoplasmic reticulum , membrane , gene
Golgi‐derived coat protein I (COPI) vesicles mediate transport in the early secretory pathway. The minimal machinery required for COPI vesicle formation from Golgi membranes in vitro consists of (i) the hetero‐heptameric protein complex coatomer, (ii) the small guanosine triphosphatase ADP‐ribosylation factor 1 (Arf1) and (iii) transmembrane proteins that function as coat receptors, such as p24 proteins. Various and opposing reports exist on a role of ArfGAP1 in COPI vesicle biogenesis. In this study, we show that, in contrast to data in the literature, ArfGAP1 is not required for COPI vesicle formation. To investigate roles of ArfGAP1 in vesicle formation, we titrated the enzyme into a defined reconstitution assay to form and purify COPI vesicles. We find that catalytic amounts of Arf1GAP1 significantly reduce the yield of purified COPI vesicles and that Arf1 rather than ArfGAP1 constitutes a stoichiometric component of the COPI coat. Combining the controversial reports with the results presented in this study, we suggest a novel role for ArfGAP1 in membrane trafficking.