title: Calcium/calmodulin-dependent protein kinase I. cDNA cloning and identification of autophosphorylation site.
abstract: Ca2+/calmodulin-dependent protein kinase I (CaM kinase I) was previously purified from bovine brain (Nairn, A. C., and Greengard, P. (1987) J. Biol. Chem. 262, 7273-7281) based on its ability to phosphorylate the synaptic vesicle protein, synapsin I at site 1. The cDNA for this protein kinase has now been cloned from both a rat and a bovine brain cDNA library and the complete amino acid sequence of rat CaM kinase I determined. The rat cDNA encoded a protein of 331 amino acids with a calculated M(r) of 37,545, and the encoded kinase was expressed in bacteria as a glutathione S-transferase fusion protein. The resulting fusion protein was purified by Sepharose-CaM affinity chromatography and shown to be totally dependent on Ca2+ and CaM for activity. Furthermore, the purified kinase phosphorylates synapsin I at the same site (site 1) as the endogenous brain enzyme. CaM kinase I is homologous to other known protein kinases and contains all nine invariant amino acids conserved in the catalytic domain of this class of enzymes. CaM kinase I was most identical to CaM kinase II both in the catalytic domain and in a short region at the COOH-terminal that is predicted to be the calmodulin-binding domain. CaM kinase I appeared to be encoded by a single gene. RNase protection assays detected the mRNA encoding CaM kinase I in all tissues examined. High concentrations of the kinase mRNA were found in all regions of the brain with frontal cortex showing the greatest level. CaM kinase I was autophosphorylated in a Ca2+/CaM-dependent manner at a threonyl residue (Thr-177) which is located at a position equivalent to that of the threonyl residue (Thr-197) autophosphorylated in cAMP-dependent protein kinase.
authors.affiliation: Laboratory of Molecular and Cellular Neuroscience, Rockefeller University, New York, New York 10021.
authors.forename: M R
authors.initials: MR
authors.lastname: Picciotto
authors.forename: A J
authors.initials: AJ
authors.lastname: Czernik
authors.forename: A C
authors.initials: AC
authors.lastname: Nairn
mesh_terms: D000311:Adrenal Glands / Q000201:enzymology; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D001921:Brain / Q000201:enzymology; D054729:Calcium-Calmodulin-Dependent Protein Kinase Type 1; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000235:genetics* / Q000378:metabolism; D002417:Cattle; D003001:Cloning, Molecular; D018076:DNA, Complementary; D004926:Escherichia coli; D008099:Liver / Q000201:enzymology; D008168:Lung / Q000201:enzymology; D008969:Molecular Sequence Data; D010766:Phosphorylation; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017386:Sequence Homology, Amino Acid
chemical_list: D018076:DNA, Complementary; D012333:RNA, Messenger; D054729:Calcium-Calmodulin-Dependent Protein Kinase Type 1; D017871:Calcium-Calmodulin-Dependent Protein Kinases; C517599:Camk1 protein, rat; C517682:Pnck protein, rat