1995 Fiscal Year Final Research Report Summary
Roles of C Kinase Substrate Protein, MARCKS and GAP-43, in Neurotransmitter Release
| Project/Area Number |
06680773
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
Neurochemistry/Neuropharmacology
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| Research Institution | Fujita Health University |
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Principal Investigator |
TANIGUCHI Hisaaki Inst.Comprehensive Med.Sci., Fujita Health University Assistant Prof., 総合医科学研究所, 助教授 (10257636)
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| Co-Investigator(Kenkyū-buntansha) |
FURUHASHI Kiyoshi Inst.Comprehensive Med.Sci., Fujita Health University Instructor, 総合医科学研究所, 助手 (90222273)
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| Project Period (FY) |
1994 – 1995
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| Keywords | Mass spectrometry / Protein / Structure / Posttranslational modification / Phosphorylation / Synapse |
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| Research Abstract |
We have established an LC/MS system, in which a capillary HPLC column is connected on-line to an electrospray mass spectrometer, and studied posttranslational modificaitons of brain-specific phosphoproteins such as MARCKS,GAP-43, synapsin I,and MAP1B.The results obtained revealed novel phosphorylation sites including Ser (Thr) -Pro motif, suggesting that these substrate proteins of PKC,calmodulin-dependent protein kinase II or casein kinase II,are in vivo substrates of so-called proline-directed protein kinase. The in vitro phosphorylation experiments with MAP kinase and Cdk5, which are highly expressed in the brain, demonstrated that these kinases site-specifically phosphorylate the proteins. Other unknown protein kinases with the SP specificity, may also exist in the brain. Phosphorylation of synapsin I affected the bunding activity of actin filaments. These results suggest that the proline-directed protein kinases in addition to PKC and calmodulin-dependent protein kinase II play important roles in the regulation of neurotransmitter release. Furthermore, we have also demonstrated that the phosphorylation of MAP1B is essential for the synapse formation in the cultured cortical neurons. These studies established the importance of the proline-directed protein kinases in the brain funcitons.
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