Gamma-COP appendage domain - structure and function

Traffic. 2004 Feb;5(2):79-88. doi: 10.1111/j.1600-0854.2004.00158.x.


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 beta-, gamma-, delta- and zeta-COP subunits which are distantly homologous to AP clathrin adaptor subunits. The second consists of the alpha-, beta'- and epsilon-COP subunits. Here, we present the structure of the appendage domain of gamma-COP and show that it has a similar overall fold as the alpha-appendage of AP2. Again, like the alpha-appendage the gamma-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 gamma-COP this site binds to a Glo3p orthologue, ARFGAP2. On the basis of mutations in the yeast homologue of gamma-COP, Sec21p, a second binding site is proposed to exist on the gamma-COP appendage that interacts with the alpha,beta',epsilon COPI subcomplex.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • ADP-Ribosylation Factors / metabolism
  • Amino Acid Sequence
  • Animals
  • Binding Sites
  • Coat Protein Complex I / chemistry
  • Coat Protein Complex I / genetics
  • Coat Protein Complex I / metabolism*
  • Crystallography, X-Ray
  • Fungal Proteins / chemistry
  • Fungal Proteins / metabolism*
  • GTPase-Activating Proteins / metabolism
  • Humans
  • Macromolecular Substances
  • Models, Molecular
  • Molecular Sequence Data
  • Protein Binding
  • Protein Conformation*
  • Protein Folding
  • Protein Structure, Tertiary
  • Protein Subunits / chemistry
  • Protein Subunits / genetics
  • Protein Subunits / metabolism*
  • Rats
  • Sequence Alignment
  • Transport Vesicles / metabolism


  • Coat Protein Complex I
  • Fungal Proteins
  • GTPase-Activating Proteins
  • Macromolecular Substances
  • Protein Subunits
  • ADP-Ribosylation Factors