Yos1p is a novel subunit of the Yip1p-Yif1p complex and is required for transport between the endoplasmic reticulum and the Golgi complex

• Published in: Molecular biology of the cell 2005-04, Vol.16 (4), p.1673-1683
• Main Authors: Heidtman, Matthew, Chen, Catherine Z, Collins, Ruth N, Barlowe, Charles
• Format: Article
• Language: English
• Subjects: Adaptor Proteins, Vesicular Transport; Amino Acid Sequence; Animals; Endoplasmic Reticulum - metabolism; Genes, Suppressor; Golgi Apparatus - metabolism; Humans; Membrane Proteins - chemistry; Membrane Proteins - genetics; Membrane Proteins - metabolism; Microscopy, Electron; Molecular Sequence Data; Multiprotein Complexes - chemistry; Multiprotein Complexes - metabolism; Mutation - genetics; Phenotype; Protein Binding; Protein Subunits - genetics; Protein Subunits - metabolism; Protein Transport; Saccharomyces cerevisiae - cytology; Saccharomyces cerevisiae - genetics; Saccharomyces cerevisiae - metabolism; Saccharomyces cerevisiae Proteins - chemistry; Saccharomyces cerevisiae Proteins - genetics; Saccharomyces cerevisiae Proteins - metabolism; Saccharomyces cerevisiae Proteins - secretion; Sequence Alignment; Time Factors; Vesicular Transport Proteins - chemistry; Vesicular Transport Proteins - genetics; Vesicular Transport Proteins - metabolism; Vesicular Transport Proteins - secretion
• ISSN: 1059-1524; 1939-4586
• DOI: 10.1091/mbc.E04-10-0873

Yeast Yip1p is a member of a conserved family of transmembrane proteins that interact with Rab GTPases. Previous studies also have indicated a role for Yip1p in the biogenesis of endoplasmic reticulum (ER)-derived COPII transport vesicles. In this report, we describe the identification and characterization of the uncharacterized open reading frame YER074W-A as a novel multicopy suppressor of the thermosensitive yip1-4 strain. We have termed this gene Yip One Suppressor 1 (YOS1). Yos1p is essential for growth and for function of the secretory pathway; depletion or inactivation of Yos1p blocks transport between the ER and the Golgi complex. YOS1 encodes an integral membrane protein of 87 amino acids that is conserved in eukaryotes. Yos1p localizes to ER and Golgi membranes and is efficiently packaged into ER-derived COPII transport vesicles. Yos1p associates with Yip1p and Yif1p, indicating Yos1p is a novel subunit of the Yip1p-Yif1p complex.