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

Abstract

Constitutive secretory transport in eukaryotes is hkdy to be mediated by non-clathrin-eoated v¢~icle~, which have been b.olatcd and characterized [(1989) Cell 58, 329-336; (1991) Nature 349, 215-220]. They contain a set of coat ploteins (COPs) which are aho likely to exist in a preformed cyto~olic complex named eoatomer [(1991) Nature 349, 248-250]. From peptide sequence and eDNA ~trueture eomparmons evidence is presented that one of the subumts of coatomer, 7-COP, is a true constituent of non-clathrin-coated vehicles, and that ?'-COP is related to sec 21. a secretory mutant of tile yeast Saccharono, ce~ cervhlae.

An endosomal beta COP is involved in the pH-dependent formation of transport vesicles destined for late endosomes.

“…The CM1A10 anti-coatomer antibody (Orci et al, 1993b) and the anti-~COP antibody (Hara- Kuge et al, 1994) were gifts from J. Rothman (Sloan-Kettering Institute, New York, NY). The antibody against ~COP (Stenbeck et al, 1992) was a gift from F. Wieland (Ruprecht Karls University, Heidelberg, Germany). The antibody against ERGIC53 was a gift from H.-P. Hauri (Biocenter, Basel, Switzerland).…”

Specific Interaction of Golgi Coatomer Protein α-COP with Phosphatidylinositol 3,4,5-Trisphosphate

“…␤Ј-COP is homologous to ␤ subunits of heterotrimeric G-proteins. ␥-COP binds to dilysine motifs of membrane proteins (28) and is related to Sec 21, a secretory mutant of the yeast S. cerevisiae (29). A single point mutation in ⑀-COP has been shown to result in temperaturesensitive lethal defects in membrane transport (30).…”

A single binding site for dilysine retrieval motifs and p23 within the γ subunit of coatomer

“…Their coat is composed of two components: coatomer (2), an oligomeric protein complex that consists of seven distinct subunits [␣ to coat proteins, (COPs)] (3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14), and ADP-ribosylation factor 1 (ARF1) (15,16). The major membrane proteins of COPI vesicles are p24 (17) and p23 (18), members of the p24 family of type I membrane proteins, characterized by a large luminal domain, a single transmembrane domain and a short cytoplasmic tail (17).…”