Pep7p provides a novel protein that functions in vesicle-mediated transport between the yeast Golgi and endosome.
Pep7p provides a novel protein that functions in vesicle-mediated transport between the yeast Golgi and endosome.
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Pep7p 提供了一种新型蛋白质，可在酵母高尔基体和内体之间的囊泡介导的运输中发挥作用。
DOI：
10.1091/mbc.8.5.871
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发表时间：
1997
影响因子：
3.3
通讯作者：
Jones,EW
中科院分区：
文献类型：
--
作者：
Webb,GC;Zhang,J;Garlow,SJ;Wesp,A;Riezman,H;Jones,EW
酿酒酵母pep 7突变体在将可溶性液泡水解酶运输到溶酶体样液泡方面有缺陷。PEP 7是一个非必需基因，编码515个氨基酸的亲水性蛋白。一个富含半胱氨酸的三重基序在N-末端的一半的多肽显示惊人的相似性，在许多其他真核生物蛋白质中发现的序列。这些蛋白质中的几种被认为在液泡/溶酶体途径中起作用。改变该基序中高度保守的半胱氨酸残基的突变导致Pep 7 p功能的丧失。动力学研究表明，Pep 7 p的功能是必需的运输高尔基体前体的可溶性水解酶羧肽酶Y，蛋白酶A，和蛋白酶B的内体。整合膜水解酶碱性磷酸酶通过不需要Pep 7 p功能的平行细胞内途径转运到液泡。pep 7突变体积累了40-60-nm的囊泡群体，表明Pep 7 p在囊泡介导的可溶性水解酶向内体的转运中的囊泡消耗步骤中起作用。而pep 7突变体在质膜的内吞摄取中没有表现出缺陷，突变体表现出通过内吞途径转运受体介导的大分子的缺陷。定位研究表明，Pep 7 p被发现作为一种可溶性的细胞质蛋白和相关的颗粒部分。我们的结论是Pep 7 p作为一种新的调节剂的囊泡对接和/或融合的内体功能。
Saccharomyces cerevisiae pep7 mutants are defective in transport of soluble vacuolar hydrolases to the lysosome-like vacuole. PEP7 is a nonessential gene that encodes a hydrophilic protein of 515 amino acids. A cysteine-rich tripartite motif in the N-terminal half of the polypeptide shows striking similarity to sequences found in many other eukaryotic proteins. Several of these proteins are thought to function in the vacuolar/lysosomal pathway. Mutations that change highly conserved cysteine residues in this motif lead to a loss of Pep7p function. Kinetic studies demonstrate that Pep7p function is required for the transport of the Golgi-precursors of the soluble hydrolases carboxypeptidase Y, proteinase A, and proteinase B to the endosome. Integral membrane hydrolase alkaline phosphatase is transported to the vacuole by a parallel intracellular pathway that does not require Pep7p function. pep7 mutants accumulate a 40-60-nm vesicle population, suggesting that Pep7p functions in a vesicle consumption step in vesicle-mediated transport of soluble hydrolases to the endosome. Whereas pep7 mutants demonstrate no defects in endocytic uptake at the plasma membrane, the mutants demonstrate defects in transport of receptor-mediated macromolecules through the endocytic pathway. Localization studies indicate that Pep7p is found both as a soluble cytoplasmic protein and associated with particulate fractions. We conclude that Pep7p functions as a novel regulator of vesicle docking and/or fusion at the endosome.