A Structure-Based Mechanism for Arf1-Dependent Recruitment of Coatomer to Membranes

作者：Yu Xinchao; Breitman Marianna; Goldberg Jonathan^*

来源：Cell, 2012, 148(3): 530-542.

DOI：10.1016/j.cell.2012.01.015

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 gamma zeta-COP subcomplex of coatomer. Structure-guided biochemical analysis reveals that a second Arf1-GTP molecule binds to beta delta-COP at a site common to the gamma-and beta-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.

• 出版日期2012-2-3