| Project/Area Number |
08680852
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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 |
Neurochemistry/Neuropharmacology
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| Research Institution | The Institute of Physical and Chemical Research (RIKEN) |
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Principal Investigator |
HIRATA Yoko Genes of Neural System, Frontier Researcher, 運動遺伝子研究チーム, フロンティア研究員 (50271523)
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| Co-Investigator(Kenkyū-buntansha) |
KIUCHI Kazutoshi Genes of Neural System, Team Leader, 運動遺伝子研究チーム, チームリーダー(研究 (30135339)
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| Project Period (FY) |
1996 – 1997
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| Project Status |
Completed (Fiscal Year 1997)
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| Budget Amount *help |
¥1,200,000 (Direct Cost: ¥1,200,000)
Fiscal Year 1997: ¥1,200,000 (Direct Cost: ¥1,200,000)
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| Keywords | Calpain / Limited proteolysis / NGFI-B(Nur77) / Nurr1 / Protein Kinase Cbeta / Rat brain / NGFI-B kinase / Protein kinase C beta |
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| Research Abstract |
The NGFI-B, also called nur77, is an immediate-early gene that encodes a member of the steroid-thyroid hormone receptor superfamily, a class of ligand-dependent transcriptional regulators, although a ligand for the NGFI-B protein has not been identified. It is rapidly synthesized and phosphorylated in PC12 cells in response to nerve growth factor (NGF). We have demonstrated previously that in vitro phosphorylation of NGFI-B at Ser35O reduces it's ability to bind to the NBRE.NGFI-B kinase I has been identified as the kinase that phosphorylates NGFI-B at Ser35O following NGF treatment of PC12 cells. In this study, we found that NGFI-B kinase I activity appears in rat brain during embryogenesis and that the major postnatal form (approximately 50 kDa) is different from the embryonic type (90 kDa). We purified NGFI-B kinase (p50 NGFI-B kinase) from rat brain (8-10 weeks, 60 g). NH_2-terminal sequencing of the enzyme revealed identity to amino acids 312 to 324 of protein kinase C (PKC) beta. Furthermore, anti-PKC beta antibodies raised against COOH-terminal peptides of the two PKC beta isoforms recognized p50 NGFI-B kinase, suggesting that the adult form of NGFI-B kinase is a COOH-terminal fragment of PKC beta, a constitutive active form due to a lack of the regulatory domain. Finally, enzymes immunoprecipitated from rat brain by anti-PKC beta I and II antibodies phosphorylate NGFI-B at Ser35O in a Ca^<2+> and phospholipid-independent manner. A significant role for this enzyme fragment was originally suggested by the report that Ca^<2+>- dependent neutral proteases I and II (calpain I and II) cleave PKC beta to produce a catalytically active fragment that is free of the regulatory domain. These results indicate that multiple protein kinases could be involved in the post-translational modification of NGFI-B and that limited proteolysis of PKC beta may be important in the regulation of NGFI-B activity after the birth.
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