γ‐COP, a coat subunit of non‐clathrin‐coated vesicles with homology to Sec21p

Abstract
Constitutive secretory transport in eukaryotes is likely to be mediated by non‐clathrin‐coated vesicles, which have been isolated and characterized [(1989) Cell 58, 329–336; (1991) Nature 349, 215–220]. They contain a set of coat proteins (COPs) which are also likely to exist in a preformed cytosolic complex named coatomer [(1991) Nature 349, 248–250]. From peptide sequence and cDNA structure comparisons evidence is presented that one of the subunits of coatomer, γ‐COP, is a true constituent of non‐clathrin‐coated vesicles, and that γ‐COP is related to sec 21, a secretory mutant of the yeast Saccharomyces cervisiae.