2002 Fiscal Year Final Research Report Summary
Functional Analysis of an Anchoring Protein CG-NAP in the Centrosome
| Project/Area Number |
13680785
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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 |
Cell biology
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| Research Institution | Biosignal Research Center, Kobe University |
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Principal Investigator |
TAKAHASHI Mikiko Kobe University, Biosignal Research Center, Assistant Professor, バイオシグナル研究センター, 助手 (90324938)
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| Project Period (FY) |
2001 – 2002
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| Keywords | Centrosome / Microtubule Organizing Center (MTOC) / γ-Tubulin / Calmodulin / Microtubule / コイルドコイル蛋白質 |
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| Research Abstract |
Microtubule assembly is initiated by γ-tubulin ring complex (γ-TuRC). In yeast, microtubule is nucleated from γ-TuRC anchored to the amino terminus of the spindle pole body component SpcllOp, which interacts with Cmd1p (calmodulin) at the carboxyl terminus. However, mammalian protein that anchors γ-TuRC remains to be elucidated. A giant coiled-coil protein CG-NAP (c___entrosome and G___olgi localized PKN___-a___ssociated p___rotein) was localized to the centrosome via the carboxyl-terminal region. This region was found to interact with calmodulin by yeast two-hybrid screening, and shares high homology with the caroboxyl-terminal region of another centrosomal coiled-coil protein, kendrin. The amino-terminal region of either CG-NAP or kendrin indirectly associated with γ-tubulin through binding with γ-tubulin complex protein 2 (GCP2) and/or GCP3. Furthermore, endogenous CG-NAP and kendrin were coimmunoprecipitated each other, and with endogenous GCP2 and γ-tubulin, suggesting that CG-NAP and kendrin form complex and interact with γ-TuRC in vivo. These proteins were localized to the center of microtubule asters nucleated from isolated centrosomes. Pretreatment of the centrosomes by antibody to CG-NAP or kendrin moderately inhibited the microtubule aster formation, moreover, combination of these antibodies resulted in stronger inhibition. These results imply that CG-NAP and kendrin provide sites for microtubule nucleation in mammalian centrosome by anchoring γ-TuRC.
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Research Products
(14 results)
