Calcium/phospholipid regulates phosphorylation of a Mr "87k" substrate protein in brain synaptosomes.
Depolarization-induced calcium influx into rat cerebral cortex synaptosomes increased the phosphorylation of several synaptosomal proteins as examined by 32Pi incorporation. A phosphopeptide mapping technique involving NaDodSO4/polyacrylamide gels has been used to show that phosphorylation of a Mr 87,000 substrate protein is stimulated by depolarization-induced calcium influx. Phosphorylation of this Mr 87,000 substrate occurred in synaptosomal cytosol and was markedly stimulated by calcium/phosphatidylserine. Calmodulin inhibited this phosphorylation reaction. This substrate for calcium/phospholipid-dependent protein kinase is enriched in and appears to be specific to neurons.
D000818:Animals; D001693:Biological Transport, Active; D002118:Calcium / Q000378:metabolism*; D002147:Calmodulin / Q000494:pharmacology; D002540:Cerebral Cortex / Q000378:metabolism*; D003600:Cytosol / Q000378:metabolism; D008928:Mitochondria / Q000378:metabolism; D008970:Molecular Weight; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D010718:Phosphatidylserines / Q000494:pharmacology*; D010748:Phosphopeptides / Q000032:analysis; D010766:Phosphorylation; D051381:Rats; D013574:Synaptosomes / Q000187:drug effects / Q000378:metabolism*; D014701:Veratridine / Q000494:pharmacology
D002147:Calmodulin; D009419:Nerve Tissue Proteins; D010718:Phosphatidylserines; D010748:Phosphopeptides; D014701:Veratridine; D002118:Calcium