1999 Fiscal Year Final Research Report Summary
The Mechanism of Protein Targeting to and Translocation across The Mitochondrial Outermembrane
| Project/Area Number |
09308022
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Structural biochemistry
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| Research Institution | KYUSHU UNIVERSITY |
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Principal Investigator |
MIHARA Katsuyoshi Graduate School of Medical Science, Kyushu University, Professor, 大学院・医学系研究科, 教授 (40029963)
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| Co-Investigator(Kenkyū-buntansha) |
KOMIYA Tohru Graduate School of Medical Science, Kyushu University, Research Associate, 大学院・医学系研究科, 助手 (40304802)
SAKAGUCHI Masao Graduate School of Medical Science, Kyushu University,Associate Professor, 大学院・医学系研究科, 助教授 (30205736)
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| Project Period (FY) |
1997 – 1999
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| Keywords | mitochondria / protein import / membrane translation / precursor proteins / chaperones |
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| Research Abstract |
Research efforts have been dealt with the following aspects.
(1) Analysis of the function of cytoplasmic chaperones, MSF (mitochondrial import stimulation factor) and hsp70 in preprotein targeting to mitochondria ; we have shown that correct targeting of precursor proteins to mitochondrial import receptors is determined by cytoplasmic chaperones, irrespective of the presence or absence of a cleavable presequence.
(2) The mechanism of preprotein translocation across the mitochondrial outer membrane ; we have shown that specific and sequential binding of a targeting signal to strategically situated acidic receptors delivers a precursor across the outer mitochondrial membrane.
(3) Characterization of preprotein import factors of mammalian mitochondria ; we have identified and cloned tow novel import factors, metaxin and OM37, when seemed to function as the import receptors of mammalian mitochondria.
(4) The mechanism of mitochondria targeting of mitochondrail outer membrane proteins ; we have shown that the N-terminal transmembrane segment with appropriate hydrophobicity cooperates with a net positive charge in the flanking segment to function as the mitochondria targeting signal.
(5) The mechanism of cytochrome c export from mitochondria in response to apoptotic signals ; we have reconstituted the cytochome c export reaction using isolated mitochondria, cytosol, dATP (or ATP) and staurosporine. This system enabled purification of the export stimulation factor from the cytosol.
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