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γ‐COP Appendage Domain – Structure and Function
Author(s) -
Watson Peter J.,
Frigerio Gabriella,
Collins Brett M.,
Duden Rainer,
Owen David J.
Publication year - 2004
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.1600-0854.2004.00158.x
Subject(s) - copi , biology , golgi apparatus , microbiology and biotechnology , appendage , clathrin , endocytosis , biochemistry , secretory pathway , anatomy , endoplasmic reticulum , receptor
COPI‐coated vesicles mediate retrograde transport from the Golgi back to the ER and intra‐Golgi transport. The cytosolic precursor of the COPI coat, the heptameric coatomer complex, can be thought of as composed of two subcomplexes. The first consists of the β‐, γ‐, δ‐ and ζ‐COP subunits which are distantly homologous to AP clathrin adaptor subunits. The second consists of the α‐, β′‐ and ε‐COP subunits. Here, we present the structure of the appendage domain of γ‐COP and show that it has a similar overall fold as the α‐appendage of AP2. Again, like the α‐appendage the γ‐COP appendage possesses a single protein/protein interaction site on its platform subdomain. We show that in yeast this site binds to the ARFGAP Glo3p, and in mammalian γ‐COP this site binds to a Glo3p orthologue, ARFGAP2. On the basis of mutations in the yeast homologue of γ‐COP, Sec21p, a second binding site is proposed to exist on the γ‐COP appendage that interacts with the α,β′,ε COPI subcomplex.