1997 Fiscal Year Final Research Report Summary
Molecular Mechanism of Mitoshondrial Protein Import in Higher Animals
| Project/Area Number |
08457040
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
General medical chemistry
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| Research Institution | Kumamoto University |
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Principal Investigator |
MORI Masataka Kumamoto University, School of Medicine, Professor, 医学部, 教授 (40009650)
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| Co-Investigator(Kenkyū-buntansha) |
TERADA Kazutoyo Kumamoto University, School of Medicine, Assistant Professor, 医学部, 助手 (00253724)
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| Project Period (FY) |
1996 – 1997
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| Keywords | Mitochondria / Protein import / Tom20 / Ornithine transcarbamylase / Aspartate aminotransferase / Serine : pyruvate aminotransferase / Zonation |
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| Research Abstract |
Most mitochondrial proteins are synthesized in the cytosol and transported into the mitochondria via Tom complex on the outer membrane. We analyzed the roles of Tom20 using in vitro import system and cultured cell system. Import of pre-ornithine transcarbamylase (pOTC), pre-aspartate aminotransferase (pAAT) and pre-serine : pyruvate aminotransferase (pSPT) was strongly inhibited by soluble domain of Tom20. Import of these precursors was also inhibited by an antibody against Tom20. However, the degree of inhibition differed from one precursor to another. When pOTC is expressed in COS-7 cells, pOTC appeared first and then imported into the mitochondria and processed to the mature form. When Tom20 was co-expressed with pOTC,mitochondrial import and processing of pOTC was retarded. On the other hand, co-expression of soluble Tom20 had little effect. All these results indicate that Tom20 is involved in mitochondrial protein import and that the requirement of Tom20 differs among the precursor proteins.
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