| Project/Area Number |
07680682
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Functional biochemistry
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| Research Institution | KYOTO UNIVERSITY |
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Principal Investigator |
AKIYAMA Yoshinori Kyoto University, Institute for Virus Research, Instrutor, ウイルス研究所, 助手 (10192460)
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| Project Period (FY) |
1995 – 1996
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| Project Status |
Completed (Fiscal Year 1996)
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| Budget Amount *help |
¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 1996: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1995: ¥1,400,000 (Direct Cost: ¥1,400,000)
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| Keywords | FtsH / ATPase / AAA family / membrane proteins / protein degradation / SecY / F0 a / quality control / F_0a / 大腸菌 |
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| Research Abstract |
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.
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