A structure-based mechanism for Arf1-dependent recruitment of coatomer to membranes.
Budding of COPI-coated vesicles from Golgi membranes requires an Arf family G protein and the coatomer complex recruited from cytosol. Arf is also required with coatomer-related clathrin adaptor complexes to bud vesicles from the trans-Golgi network and endosomal compartments. To understand the structural basis for Arf-dependent recruitment of a vesicular ... coat to the membrane, we determined the structure of Arf1 bound to the γζ-COP subcomplex of coatomer. Structure-guided biochemical analysis reveals that a second Arf1-GTP molecule binds to βδ-COP at a site common to the γ- and β-COP subunits. The Arf1-binding sites on coatomer are spatially related to PtdIns4,5P(2)-binding sites on the endocytic AP2 complex, providing evidence that the orientation of membrane binding is general for this class of vesicular coat proteins. A bivalent GTP-dependent binding mode has implications for the dynamics of coatomer interaction with the Golgi and for the selection of cargo molecules.
Mesh Terms:
ADP-Ribosylation Factor 1, Amino Acid Sequence, Animals, COP-Coated Vesicles, Golgi Apparatus, Guanosine Triphosphate, Intracellular Membranes, Models, Molecular, Saccharomyces cerevisiae, Saccharomyces cerevisiae Proteins, Sequence Alignment
ADP-Ribosylation Factor 1, Amino Acid Sequence, Animals, COP-Coated Vesicles, Golgi Apparatus, Guanosine Triphosphate, Intracellular Membranes, Models, Molecular, Saccharomyces cerevisiae, Saccharomyces cerevisiae Proteins, Sequence Alignment
Cell
Date: Feb. 03, 2012
PubMed ID: 22304919
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