Yeast beta- and beta'-coat proteins (COP). Two coatomer subunits essential for endoplasmic reticulum-to-Golgi protein traffic.
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| Abstract |
To understand better the role of non-clathrin coat proteins in membrane traffic, we have cloned and characterized two essential genes encoding subunits of the yeast coatomer, SEC26 and SEC27. Sec26p is a 109-kDa protein that shares 43% sequence identity with mammalian beta-coat protein (beta-COP). Sec26p-depleted cells accumulate endoplasmic reticulum (ER) forms of secretory precursor proteins, and growth ceases after a dramatic accumulation of ER membranes. Sec26p overproduction partially suppresses sec27-1, a new mutant that shows a temperature-sensitive defect in ER-to-Golgi transport. The SEC27 gene was cloned, and the sequence predicts a 99.4-kDa protein with 45% sequence identity to mammalian beta'-COP. Our sequence data support a two-domain model for the SEC27 protein: a conserved amino-terminal domain, composed of five WD-40 repeats similar to those found in beta-subunits of trimeric G proteins, and a less conserved carboxyl-terminal domain. Genetic interactions connect sec27-1 and sec21-1 (coatomer gamma subunit) with the ARF1 and ARF2 genes and with the SEC22, BET1, and BOS1 genes, which encode membrane proteins involved in ER-to-Golgi transport.
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| Authors | R Duden, M Hosobuchi, S Hamamoto, M Winey, B Byers, R Schekman |
| Journal | The Journal of biological chemistry (J Biol Chem) Vol. 269 Issue 39 Pg. 24486-95 (Sep 30 1994) ISSN: 0021-9258 [Print] United States |
| PMID | 7929113 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, P.H.S.) |
| Chemical References |
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