Inhibitory effect of calmodulin on phosphorylation of NAP-22 with protein kinase C.
NAP-22, a recently identified neural tissue-enriched acidic protein, was shown to be a substrate of protein kinase C in vitro. Its phosphorylation site was assigned as Ser6 using deleted mutants expressed in Escherichia coli. Calmodulin inhibited this phosphorylation reaction. This inhibitory effect of calmodulin was dose-dependent and much stronger than its inhibitory effect to the phosphorylation of neuromodulin (GAP-43) with protein kinase C. The dissociation constant of NAP-22 and calmodulin obtained using the fluorescence change of dansyl-labeled calmodulin was much lower than that of neuromodulin and calmodulin. The phosphorylation of NAP-22 inhibited the association with calmodulin.
Graduate School, Division of Science, University of Tokyo, Japan.
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Maekawa
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Murofushi
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Nakamura
D000595:Amino Acid Sequence; D000818:Animals; D001921:Brain / Q000378:metabolism; D002147:Calmodulin / Q000378:metabolism*; D002148:Calmodulin-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D003598:Cytoskeletal Proteins; D004252:DNA Mutational Analysis; D004926:Escherichia coli / Q000235:genetics; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D011485:Protein Binding; D011493:Protein Kinase C / Q000378:metabolism*; D051381:Rats; D011994:Recombinant Proteins / Q000378:metabolism; D017384:Sequence Deletion; D012694:Serine / Q000378:metabolism; D013053:Spectrophotometry
D002147:Calmodulin; D002148:Calmodulin-Binding Proteins; D003598:Cytoskeletal Proteins; D009419:Nerve Tissue Proteins; D011994:Recombinant Proteins; C066853:Basp1 protein, rat; D012694:Serine; D011493:Protein Kinase C