Essential roles of class E Vps proteins for sorting into multivesicular bodies in Schizosaccharomyces pombe
Essential roles of class E Vps proteins for sorting into multivesicular bodies in Schizosaccharomyces pombe
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DOI：
10.1099/mic.0.2007/006072-0
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发表时间：
2007-08-01
期刊：
影响因子：
2.8
通讯作者：
Takegawa, Kaoru
中科院分区：
文献类型：
--
作者：
Iwaki, Tornoko;Onishi, Masayuki;Takegawa, Kaoru
多泡体（MVB）分选途径是许多生物学过程所必需的，包括下调细胞表面蛋白和蛋白质分选到液泡腔中。该途径的功能需要由酿酒酵母中的E类液泡蛋白分选（Vps）蛋白组成的转运所需的内体分选复合物（ESCRT），其中许多在粟酒裂殖酵母中是保守的。其中，sst 4/vps 27（与VPS 27同源）和sst 6（与VPS 23相似）已被鉴定为st 12 Delta（sst）不育的抑制因子，尽管它们的功能迄今尚未发现。在本报告中，这两个sst基因被证明是需要的真空分选羧肽酶Y（CPY）和MVB标记，泛素-GFP-羧肽酶S（Ub-GFP-CPS）融合蛋白，尽管缺乏泛素E2变异结构域在Sst 6p。各种其他E类vps同源物的破坏突变体在CPY和Ub-GFP-CPS的分选中也有缺陷。粟酒裂殖酵母具有哺乳动物AMSH同源物，sst 2。表型分析表明，Sst 2 p是一个E类Vps蛋白。总之，这些结果表明，分选成多泡体是依赖于E类Vps蛋白，包括Sst 2 p，在Sch. pombe。
The multivesicular body (MVB) sorting pathway is required for a number of biological processes, including downregulation of cell-surface proteins and protein sorting into the vacuolar lumen. The function of this pathway requires endosomal sorting complexes required for transport (ESCRT) composed of class E vacuolar protein sorting (Vps) proteins in Saccharomyces cerevisiae, many of which are conserved in Schizosaccharomyces pombe. Of these, sst4/vps27 (homologous to VPS27) and sst6 (similar to VPS23) have been identified as suppressors of sterility in ste12 Delta (sst), although their functions have not been uncovered to date. In this report, these two sst genes are shown to be required for vacuoiar sorting of carboxypeptidase Y (CPY) and an MVB marker, the ubiquitin-GFP-carboxypeptidase S (Ub-GFP-CPS) fusion protein, despite the lack of the ubiquitin E2 variant domain in Sst6p. Disruption mutants of a variety of other class E vps homologues also had defects in sorting of CPY and Ub-GFP-CPS. Sch. pombe has a mammalian AMSH homologue, sst2. Phenotypic analyses suggested that Sst2p is a class E Vps protein. Taken together, these results suggest that sorting into multivesicular bodies is dependent on class E Vps proteins, including Sst2p, in Sch. pombe.