Quality control of an integral membrane protein, SecY.

完整膜蛋白 SecY 的质量控制。

基本信息

批准号：
07680682
负责人：
AKIYAMA Yoshinori
金额：
$ 1.41万
依托单位：
KYOTO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1996
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07680682/
关键词：
FtsH ATPase AAA family membrane proteins protein degradation SecY F0 a quality control F_0a 大腸菌

项目摘要

E.coli FtsH is a membrane-bound and ATP-dependent protease whose cytosolic domain includes an AAA family segment. Members of the AAA family of ATPase are involved in various cellular processes including vesicular transport of secreted proteins, biogenesis organelles and protein degradation. The ftsH mutations stabilize overproduced SecY protein that was unstable because of the insufficient availability of the stabilizing partner (SecE). We found that another integral membrane protein, subunit a of the F_0 ATPase, became also a substrate of FtsH when it failed to be associated with other F_0 subunits. Rapid elimination of uncomplexed forms of SecY or subunit a seems to be important because their accumulation is toxic to a cell. FtsH seems to constitute membrane-bound machinery for quality control over other membrane protein complexes. In addition to the phenotypes ascribable to the proteolytic function, the ftsH mutations cause altered topology of a model membrane protein (SecY-PhoA), retardation of translocation of some secreted proteins and a defect in generation of membrane potential. In addition, growth defects and some of phenotypes of the ftsH mutants were found to be suppressible by overproduction of molecular chaperones, GroE or HtpG.These observations suggest that FtsH has chaperone-like activities. The possible chaperone-like activity of FtsH may have a role for assembly of membrane proteins.

大肠杆菌 FtsH 是一种膜结合的 ATP 依赖性蛋白酶，其胞质结构域包括 AAA 家族片段。 ATP 酶 AAA 家族的成员参与多种细胞过程，包括分泌蛋白的囊泡运输、生物发生细胞器和蛋白质降解。 ftsH 突变稳定了过量产生的 SecY 蛋白，该蛋白由于稳定伴侣 (SecE) 的可用性不足而不稳定。我们发现，另一种整合膜蛋白（F_0 ATPase 的 a 亚基）在无法与其他 F_0 亚基结合时也成为 FtsH 的底物。快速消除未复合形式的 SecY 或亚基 a 似乎很重要，因为它们的积累对细胞有毒。 FtsH 似乎构成了膜结合机制，用于对其他膜蛋白复合物进行质量控制。除了与蛋白水解功能有关的表型外，ftsH 突变还会导致模型膜蛋白 (SecY-PhoA) 的拓扑结构改变、某些分泌蛋白易位延迟以及膜电位产生缺陷。此外，发现 ftsH 突变体的生长缺陷和一些表型可通过分子伴侣、GroE 或 HtpG 的过量产生而受到抑制。这些观察结果表明 FtsH 具有类似伴侣的活性。 FtsH 可能具有的分子伴侣样活性可能在膜蛋白的组装中发挥作用。