2002 Fiscal Year Final Research Report Summary
Molecular chaperone activity of the 20S proteasome : Inhibitory activity of the substrate protein aggregation and unflodase activity
| Project/Area Number |
13470026
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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 | The University of Tokushima |
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Principal Investigator |
KIDO Hiroshi The University of Tokushima, Institute for Enzyme Research, Professor, 分子酵素学研究センター, 教授 (50144978)
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| Co-Investigator(Kenkyū-buntansha) |
OKUMURA Yuushi The University of Tokushima, Institute for Enzyme Research, Associate Professor, 分子酵素学研究センター, 助手 (70294725)
YANO Mihiro The University .of Tokushima, Institute for Enzyme Research, Associate Professor, 分子酵素学研究センター, 助教授 (40304555)
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| Project Period (FY) |
2001 – 2002
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| Keywords | Molecular chaperone / Proteasome / 19S Cap / Refolding / Aggregation of heat-denatured proteins / ATP / ADP / ATP-ADP exchange reaction |
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| Research Abstract |
Cellular proteases and molecular chaperone proteins play important roles in the intracellular protein catabolism. Among the proteases, a multi-functional 20S proteasome, which is composed of 28 low molecular mass subunits arranged in a stack of four rings, each containing seven different α- and β-subunits, plays a central role in the degradation of unfolded and/or misfolded proteins in the cytosol in cooperation with molecular chaperones. We found that the C5 in theβ-type and the C8 in theα-type subunits of the 20S proteasome reveal the activities of ATP hydrolysis and ADP-ATP exchange, which are similar to the activities of molecular chaperone and essential to the association and dissociation of substrate proteins and peptides. Furthermore, 20S proteasome reveals a chaperone-like activity, an inhibition of the aggregation of heat-denatured proteins, in an ATP-independent manner and degradation of unfolded protein in an ATP-dependent manner. These results suggest the activities of ATP hydrolysis and ATP-ADP exchange of the 20S proteasome play a role in translocation of unfolded and/or misfolded proteins into the catalytic cavity of the inside of ring-shaped 20S proteasome but not play a role in inhibition of the aggregation of heat-denatured proteins.
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