Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.11.1 (protein kinase)
 81,284 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We previously reported that rat brain Ca(2+)/calmodulin-dependent protein kinase (CaM-kinase) IV is inactivated by cAMP-dependent protein kinase (PKA) [Kameshita, I. and Fujisawa, H. (1991) Biochem. Biophys. Res. Commun. 180, 191-196]. In the preceding paper, we demonstrated that changes in the activity of CaM-kinase IV by PKA results from the phosphorylation of CaM-kinase kinase alpha by PKA and identified six phosphorylation sites, Ser(24) for autophosphorylation, and Ser(52), Ser(74), Thr(108), Ser(458), and Ser(475) for phosphorylation by PKA. In the present study, a causal relationship between the phosphorylation and change in the activity toward PKIV peptide has been studied using mutant enzymes with amino acid substitutions at the six phosphorylation sites. The following conclusions can be drawn from the experimental results: (i) Phosphorylation of Ser74 and/or unidentified sites causes an increase in activity; (ii) phosphorylation of Thr(108) or Ser(458) causes a decrease in the activity; (iii) the inhibitory effect of the phosphorylation of Thr(108) is canceled by the stimulatory effect of the phosphorylation, but that of Ser(458) is not; and (iv) the inhibitory effects of Thr(108) and Ser(458) are synergistic. In contrast to the activity toward PKIV peptide, the activity toward CaM-kinase IV appears to be decreased by the phosphorylation of Thr(108), but not significantly affected by the phosphorylation of Ser(458).
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PMID:Regulation of Ca(2+)/calmodulin-dependent protein kinase kinase alpha by cAMP-dependent protein kinase: II. Mutational analysis. 1157 71

Calmodulin-dependent protein kinase IV (CaM-kinase IV) phosphorylated calmodulin (CaM), which is its own activator, in a poly-L-Lys [poly(Lys)]-dependent manner. Although CaM-kinase II weakly phosphorylated CaM under the same conditions, CaM-kinase I, CaM-kinase kinase alpha, and cAMP-dependent protein kinase did not phosphorylate CaM. Polycations such as poly(Lys) were required for the phosphorylation. The optimum concentration of poly(Lys) for the phosphorylation of 1 microM CaM was about 10 microg/ml, but poly(Lys) strongly inhibited CaM-kinase IV activity toward syntide-2 at this concentration, suggesting that the phosphorylation of CaM is not due to simple activation of the catalytic activity. Poly-L-Arg could partially substitute for poly(Lys), but protamine, spermine, and poly-L-Glu/Lys/Tyr (6/3/1) could not. When phosphorylation was carried out in the presence of poly(Lys) having various molecular weights, poly(Lys) with a higher molecular weight resulted in a higher degree of phosphorylation. Binding experiments using fluorescence polarization suggested that poly(Lys) mediates interaction between the CaM-kinase IV/CaM complex and another CaM. The 32P-labeled CaM was digested with BrCN and Achromobacter protease I, and the resulting peptides were purified by reversed-phase HPLC. Automated Edman sequence analysis of the peptides, together with phosphoamino acid analysis, indicated that the major phosphorylation site was Thr44. Activation of CaM-kinase II by the phosphorylated CaM was significantly lower than that by the nonphosphorylated CaM. Thus, CaM-kinase IV activated by binding Ca2+/CaM can bind and phosphorylate another CaM with the aid of poly(Lys), leading to a decrease in the activity of CaM.
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PMID:Phosphorylation of calmodulin by Ca2+/calmodulin-dependent protein kinase IV. 1239 17

The Ca(2+)/calmodulin-dependent protein kinase kinases alpha and beta (CaMKKs alpha and beta) are novel members of the CaM kinase family. The CaMKKbeta was cloned from mouse brain. The deduced amino acid sequence shared 96.43% homology with the rat CaMKKbeta. Both the alpha and beta isoforms were widely distributed throughout the adult mouse brain. Additionally, all peripheral tissues examined displayed CaMKK alpha and beta expression.
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PMID:Cloning of mouse Ca2+/calmodulin-dependent protein kinase kinase beta (CaMKKbeta) and characterization of CaMKKbeta and CaMKKalpha distribution in the adult mouse brain. 1265 22

Calcium/Calmodulin-dependent Protein Kinase Kinase 2 (CAMKK2) acts as a signaling hub, receiving signals from various regulatory pathways and decoding them via phosphorylation of downstream protein kinases - such as AMPK (AMP-activated protein kinase) and CAMK types I and IV. CAMKK2 relevance is highlighted by its constitutive activity being implicated in several human pathologies. However, at present, there are no selective small-molecule inhibitors available for this protein kinase. Moreover, CAMKK2 and its closest human homolog, CAMKK1, are thought to have overlapping biological roles. Here we present six new co-structures of potent ligands bound to CAMKK2 identified from a library of commercially-available kinase inhibitors. Enzyme assays confirmed that most of these compounds are equipotent inhibitors of both human CAMKKs and isothermal titration calorimetry (ITC) revealed that binding to some of these molecules to CAMKK2 is enthalpy driven. We expect our results to advance current efforts to discover small molecule kinase inhibitors selective to each human CAMKK.
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PMID:Binding and structural analyses of potent inhibitors of the human Ca2+/calmodulin dependent protein kinase kinase 2 (CAMKK2) identified from a collection of commercially-available kinase inhibitors. 3171 18


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