Finken-Eigen M, Müller S, Köhrer K
Biologisch-Medizinisches Forschungszentrum, Heinrich-Heine-Universität Düsseldorf, Germany.
Biol Chem. 1997 Oct;378(10):1187-91.
The gene product of the yeast VPS1 gene is a member of a family of high-molecular-weight GTP-binding proteins that are involved in diverse cellular processes. The Vps1 protein (Vps1p) was shown to perform an essential function in the yeast secretory pathway. Here, we report the isolation and characterization of a mutant allele of the VPS1 gene, causing a dominant-negative vacuolar protein sorting (vps) defect, as demonstrated by the mislocalization of the vacuolar hydrolase carboxypeptidase Y (CPY). DNA sequence analysis of the mutant vps1 allele (vps1d-293) revealed a single point mutation, resulting in an amino acid exchange at position 293 from Ala to Asp. The mutation is located downstream of the tripartite GTP-binding motif found in the amino-terminal half of the protein. The observation that expression of wild-type Vps1p partially suppressed the dominant-negative CPY sorting phenotype indicates competition of a non-functional mutant Vps1 protein and a functional wild-type VPS1p for a Vps1p-binding site of an as yet unknown vacuolar protein sorting factor.
酵母VPS1基因的基因产物是参与多种细胞过程的高分子量GTP结合蛋白家族的成员。Vps1蛋白（Vps1p）在酵母分泌途径中发挥重要作用。在此，我们报告了VPS1基因一个突变等位基因的分离和特征，该突变导致显性负性液泡蛋白分选（vps）缺陷，液泡水解酶羧肽酶Y（CPY）的定位错误证明了这一点。对突变的vps1等位基因（vps1d - 293）的DNA序列分析揭示了一个单点突变，导致第293位氨基酸从丙氨酸变为天冬氨酸。该突变位于蛋白质氨基末端一半中发现的三方GTP结合基序的下游。野生型Vps1p的表达部分抑制显性负性CPY分选表型这一观察结果表明，无功能的突变Vps1蛋白和有功能的野生型Vps1p竞争一个未知的液泡蛋白分选因子的Vps1p结合位点。
