GOS1P, A SACCHAROMYCES-CEREVISIAE SNARE PROTEIN INVOLVED IN GOLGI TRANSPORT

Specific transport between secretory compartments requires that vesicu lar carriers contain targeting proteins known as SNAREs, Ten V-SNAREs have been identified in the genome of the yeast Saccharomyces cerevisi ae by sequence analysis. We report here the characterization of Gos1p, a v-SNARE localized to the Golgi compartment and likely homolog of th e mammalian protein GOS-28/GS28, Gos1p is a type II membrane protein w ith characteristic SNARE sequence hallmarks and is functionally a SNAR E protein. Gos1p was originally identified as a 28 kDa protein in an i mmunoprecipitate of the cis-Golgi t-SNARE Sed5p, This interaction betw een Sed5p and Gos1p is direct as demonstrated by in vitro binding with recombinant proteins. Deletion of GOS1 results in viable haploids wit h modest growth and secretory defects, Close examination of the secret ory phenotype of GOS1-disrupted cells suggests that Gos1p may play a r ole in multiple transport steps, specifically ER-Golgi and/or intra-Go lgi transport. (C) 1998 Federation of European Biochemical Societies.