The yeast VPS17 gene encodes a membrane-associated protein required for the sorting of soluble vacuolar hydrolases.

摘要: vps17 mutants missort and secrete several vacuolar hydrolases. To analyze the role of VPS17 gene in protein delivery, we have cloned this by complementation sorting defects a vps17-5 mutant. Disruption had no effect on viability haploid yeast cells, although they show an obvious defect morphology. vps17-disrupted cells contain numerous small vacuole-like compartments also exhibit severe carboxypeptidase Y (CPY), soluble hydrolase. 95% CPY is missorted secreted from mutant cells. Vacuolar two other hydrolases, proteinase A B, affected, but to lesser extent. Delivery maturation membrane alkaline phosphatase does not appear be affected delta strain. The DNA sequence clone indicates that encodes 551-amino-acid with calculated molecular mass 63.1 kDa. hydrophilic contains N-terminal signal or hydrophobic membrane-spanning domains, indicating Vps17p enter secretory pathway. Using Vps17p-specific polyclonal antiserum, demonstrated Vps17 modified N-linked carbohydrates at any its four potential glycosylation sites. protein, however, fractionates particulate fraction after centrifugation 100,000 x g. can released treatment either Triton X-100 urea, peripherally associated crude fraction. Based these results, propose functions cytoplasmic surface some intracellular organelle, possibly Golgi complex intermediate vacuole transport, facilitate delivery traffic, appears occur mechanism independent function.