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A COPI coat subunit interacts directly with an early‐Golgi localized Arf exchange factor
Author(s) -
Deng Yi,
GolinelliCohen MariePierre,
Smirnova Elena,
Jackson Catherine L
Publication year - 2009
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/embor.2008.221
Subject(s) - copi , adp ribosylation factor , golgi apparatus , guanine nucleotide exchange factor , microbiology and biotechnology , copii , protein subunit , biology , clathrin , endosome , gtpase , vesicle , intracellular , endoplasmic reticulum , secretory pathway , membrane , biochemistry , gene
Arf (ADP‐ribosylation factor) family small G proteins are crucial regulators of intracellular transport. The active GTP‐bound form of Arf interacts with a set of proteins—effectors—which mediate the downstream signalling events of Arf activation. A well‐studied class of Arf1 effectors comprises the coat complexes, such as the cis ‐Golgi‐localized COPI (coat protein complex I) coat, and trans ‐Golgi network‐endosomal clathrin coats. At least five different coats require Arf1‐GTP to localize to organelle membranes. How a single Arf protein recruits different coat complexes to distinct membrane sites raises the question of how specificity is achieved. Here, we propose a molecular mechanism of this specificity for the COPI coat by showing a direct and specific interaction between a COPI subunit and a cis ‐Golgi localized subfamily of Arf guanine nucleotide exchange factors (GEFs) that takes place independently of Arf1 activation. In this way, a specific output on Arf1 activation can be programmed before the exchange reaction by the GEF itself.