Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.11.17 (CaMKII)
 4,029 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Characteristics of the autophosphorylation of Ca2+/calmodulin-dependent protein kinase II (CaM kinase II) from the cytosol and in the postsynaptic densities (PSD) of rat brain were investigated. Several proteins were surveyed for their abilities to serve as a substrate for non-autophosphorylated and autophosphorylated CaM kinase IIs from the cytosol and PSD. The tested substrates were separated into two groups. Autophosphorylation of the kinase slightly decreased or did not change its activities towards substrates of the first group: myosin light chain of chicken gizzard, synapsin I, tau factor and microtubule-associated protein 2. In contrast, autophosphorylation of the enzyme increased its activities towards substrates of the second group: syntide-2, histone H1, calcineurin and myelin basic protein. The Ca2+/calmodulin-independent kinase activity increased by autophosphorylation with any of substrates tested. Similar results were obtained with the cytosolic and PSD CaM kinase II. Trifluoperazine and mastoparan, calmodulin binding antagonists, inhibited the activity of the non-autophosphorylated CaM kinase II, but had no effect or only a slight inhibitory effect on the activity of the autophosphorylated CaM kinase II, indicating that the autophosphorylated kinase has no requirement for calmodulin for Ca(2+)-dependent activity and/or a higher affinity for calmodulin The results suggest that the autophosphorylation of CaM kinase II is a subtle mechanism for regulating the interaction between the enzyme and substrate.
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PMID:Autophosphorylation of Ca2+/calmodulin-dependent protein kinase II: effects on interaction between enzyme and substrate. 164 40

Recent studies have identified protein tyrosine phosphorylation as a major intracellular signaling pathway. However, little is known about regulation of this signaling pathway in neuronal systems. To help identify changes in levels of protein tyrosine phosphorylation in brain, we have utilized specific anti-phosphotyrosine antibodies to detect phosphotyrosine-containing proteins by immunoblotting techniques. We have found that electroconvulsive treatment induces a selective increase in tyrosine phosphorylation of a soluble 40-kDa protein. The rise is rapid and transient, reaching maximal levels at 1-2 min and returning to basal levels by 8 min. The phosphotyrosine-containing 40-kDa protein is most prominent in hippocampus, smaller in neocortex, and not detected in brainstem or cerebellum. A phosphotyrosine-containing 42-kDa protein present in several cell types has recently been identified as a serine/threonine phosphotransferase, referred to as microtubule-associated protein 2 kinase. Comparison of the levels of tyrosine phosphorylation of the 40-kDa protein and microtubule-associated protein 2 kinase activity during column chromatography of hippocampal extracts demonstrates that the phosphotyrosine-containing 40-kDa protein and microtubule-associated protein 2 co-purify. Moreover, the tyrosine phosphorylation of the 40-kDa protein and microtubule-associated protein 2 kinase activity are increased to a similar extent following electroconvulsive treatment. These findings suggest that the phosphotyrosine-containing 40-kDa protein identified in brain is closely related to microtubule-associated protein 2 kinase.
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PMID:Electroconvulsive treatment induces a rapid and transient increase in tyrosine phosphorylation of a 40-kilodalton protein associated with microtubule-associated protein 2 kinase activity. 170 29

Growth factor activation of serine/threonine protein kinases was studied by treating quiescent Swiss 3T3 cells with epidermal growth factor (EGF) and examining cytosolic extracts for protein kinase activity under conditions inhibitory to calcium- and cyclic nucleotide-dependent kinases. Cytosolic extracts of cells stimulated for 5 min were fractionated by Mono Q fast protein liquid chromatography. Eight peaks of kinase activity were resolved, of which five were stimulated by EGF treatment of cells. These peaks were revealed using the synthetic peptide Arg-Arg-Leu-Ser-Ser-Leu-Arg-Ala (S6 peptide), 40 S ribosomal S6 protein, glycogen synthase, microtubule-associated protein 2, and myelin basic protein as substrates. The peaks varied in the kinetics of their activation by EGF and in their response to insulin. Selected peaks were resolved further by sizing gel chromatography. The results together indicate that at least seven distinct fractions of cytosolic kinase activities are stimulated in Swiss 3T3 cells by EGF. One of these, which phosphorylates both S6 protein and S6 peptide, is similar to the S6 kinase characterized previously in this cell line by others. Four additional activities that also phosphorylate the S6 protein and S6 peptide appear unrelated to this enzyme. Finally, two kinase activities that phosphorylate both myelin basic protein and microtubule associated protein 2 are EGF stimulated. One is similar to an insulin-stimulated microtubule-associated protein 2 kinase described in other cell lines whereas the other seems to represent a novel activity. Several of these EGF-stimulated activities were inactivated by protein phosphatases, suggesting that they might be regulated by phosphorylation.
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PMID:Identification of multiple epidermal growth factor-stimulated protein serine/threonine kinases from Swiss 3T3 cells. 214 53

A type II calcium/calmodulin-dependent protein kinase (CaM kinase II) was purified approximately 300-fold from cultured neuroblastoma/glioma (NG108) cell homogenate. The purification of the kinase, which used a combination of differential centrifugation and chromatography on cation-exchange, calmodulin-affinity, and gel-filtration resins, was monitored by the ability of the kinase to phosphorylate the high-molecular-weight microtubule-associated protein 2 (MAP-2). The kinase was compared with authentic CaM kinase II purified from rat brain cytosol. Based upon holoenzyme molecular weight, subunit composition and molecular weight, calcium-dependent calmodulin-binding to subunits, calcium/calmodulin-dependent autophosphorylation of subunits, substrate specificity, apparent km's for ATP and calmodulin, phosphopeptide maps of subunits, time course, and heat lability, the kinase was identified as a type II calcium/calmodulin-dependent protein kinase. When cellular differentiation was induced under specific conditions of cell culture, a significant increase in the apparent activity and amount of the kinase per mg protein was observed relative to control cells. These studies suggest that there is an increase in CaM kinase II expression during cellular differentiation, which may relate to the concurrent development of electrical excitability, synaptogenesis, and elaboration of cytoskeletal elements. Thus, the NG108 cell should provide a useful model to study the physiological functions of CaM kinase II.
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PMID:Differentiation increases type II calmodulin-dependent protein kinase in the neuroblastoma/glioma cell line 108CC15 (NG108-15). 253 90

Protein phosphatase C was purified 140-fold from bovine brain with 8% yield using histone H1 phosphorylated by the catalytic subunit of cyclic AMP-dependent protein kinase (cyclic AMP-kinase). Brain protein phosphatase C was considered to consist of 10 and 90%, respectively, of the catalytic subunits of protein phosphatases 1 and 2A on the basis of the effects of ATP and inhibitor-2. Protein phosphatase C dephosphorylated microtubule-associated protein 2 (MAP2), tau factor, and tubulin phosphorylated by a multifunctional Ca2+/calmodulin-dependent protein kinase (calmodulin-kinase) and the catalytic subunit of cyclic AMP-kinase. The properties of dephosphorylation of MAP2, tau factor, and tubulin were compared. The Km values were in the ranges of 1.6-2.7 microM for MAP2 and tau factor. The Km value for tubulin decreased from 25 to 10-12.5 microM in the presence of 1.0 mM Mn2+. No difference in kinetic properties of dephosphorylation was observed between the substrates phosphorylated by the two kinases. Protein phosphatase C did not dephosphorylate the native tubulin, but universally dephosphorylated tubulin phosphorylated by the two kinases. The holoenzyme of protein phosphatase 2A from porcine brain could also dephosphorylate MAP2, tau factor, and tubulin phosphorylated by the two kinases. The phosphorylation of MAP2 and tau factor by calmodulin-kinase separately induced the inhibition of microtubule assembly, and the dephosphorylation by protein phosphatase C removed its inhibitory effect. These data suggest that brain protein phosphatases 1 and 2A are involved in the switch-off mechanism of both Ca2+/calmodulin-dependent and cyclic AMP-dependent regulation of microtubule formation.
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PMID:Dephosphorylation of microtubule proteins by brain protein phosphatases 1 and 2A, and its effect on microtubule assembly. 283 18

Sphingosine is a potent inhibitor of several calmodulin-dependent enzymes. The multifunctional Ca2+/calmodulin-dependent protein kinase, a Ca2+/calmodulin-dependent phosphodiesterase, and smooth muscle myosin light chain kinase are inhibited in vitro at concentrations previously shown to inhibit protein kinase C. Inhibition of each of the enzymes is competitive with calmodulin, suggesting that sphingosine may be a calmodulin antagonist. In the pituitary cell line GH3, sphingosine inhibits the phosphorylation of microtubule-associated protein 2 by the multifunctional Ca2+/calmodulin-dependent protein kinase and the phosphorylation of elongation factor 2 by Ca2+/calmodulin-dependent kinase III. These findings suggest that sphingosine, in blocking the effects of both the Ca2+.calmodulin complex and of diacylglycerol, may be a very effective inhibitor of both branches of the phosphatidylinositol signaling pathway. By extension, caution should be exercised in the use of sphingosine as a diagnostic test for the involvement of protein kinase C in biological processes.
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PMID:Sphingosine inhibits calmodulin-dependent enzymes. 284 4

Calmodulin-dependent protein kinase II (CaM kinase II) is associated with microtubule preparations and phosphorylates several endogenous proteins including microtubule-associated protein 2, tubulin, and an 80,000-dalton protein doublet (pp80). We now report that pp80 is identical to synapsin I by all criteria studied including molecular weight, isoelectric point, phosphopeptide mapping of cAMP- and calmodulin-dependent phosphorylated protein, comigration with authentic synapsin I, and sensitivity to digestion with collagenase. Synapsin I and CaM kinase II were found in association with both microtubule preparations and preparations enriched in neurofilaments. Antibodies to synapsin I specifically labeled neurofilaments prepared in vitro. Immunocytochemical studies on rat brain tissue demonstrated synapsin I immunoreactivity specifically associated with the neuronal cytoskeleton as well as synaptic vesicles. The observed synapsin I staining on cytoskeletal elements was considerably diminished or abolished by the inclusion of Triton X-100 in the staining solutions. These results indicate that synapsin I is associated with the cytoskeleton and may be an important link between cytoskeletal elements as well as between the cytoskeleton and membrane.
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PMID:Association of synapsin I with neuronal cytoskeleton. Identification in cytoskeletal preparations in vitro and immunocytochemical localization in brain of synapsin I. 308 74

In previous studies, we described a soluble Ca2+/calmodulin-dependent protein kinase which is the major Ca2+/calmodulin-dependent microtubule-associated protein 2 (MAP-2) kinase in rat brain [Schulman, H. (1984) J. Cell Biol. 99, 11-19; Kuret, J. A., & Schulman, H. (1984) Biochemistry 23, 5495-5504]. We now demonstrate that this protein kinase has broad substrate specificity. Consistent with a multifunctional role in cellular physiology, we show that in vitro the enzyme can phosphorylate numerous substrates of both neuronal and nonneuronal origin including vimentin, ribosomal protein S6, synapsin I, glycogen synthase, and myosin light chains. We have used MAP-2 to purify the enzyme from rat lung and show that the brain and lung kinases have nearly indistinguishable physical and biochemical properties. A Ca2+/calmodulin-dependent protein kinase was also detected in rat heart, rat spleen, and in the ring ganglia of the marine mollusk Aplysia californica. Partially purified MAP-2 kinase from each of these three sources displayed endogenous phosphorylation of a 54 000-dalton protein. Phosphopeptide analysis reveals a striking homology between this phosphoprotein and the 53 000-dalton autophosphorylated subunit of the major rat brain Ca2+/calmodulin-dependent protein kinase. The enzymes phosphorylated MAP-2, synapsin I, and vimentin at peptides that are identical with those phosphorylated by the rat brain kinase. This enzyme may be a multifunctional Ca2+/calmodulin-dependent protein kinase with a widespread distribution in nature which mediates some of the effects of Ca2+ on microtubules, intermediate filaments, and other cellular constituents in brain and other tissues.
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PMID:Ca2+/calmodulin-dependent microtubule-associated protein 2 kinase: broad substrate specificity and multifunctional potential in diverse tissues. 407 98

In an earlier study I demonstrated that rat brain cytosol contains a Ca2+/calmodulin-dependent protein kinase activity that phosphorylates microtubule-associated protein 2 (MAP-2) but not MAP-1. Comparison of sites of phosphate incorporated in MAP-2 catalyzed by the Ca2+/calmodulin-dependent kinase activity and the cyclic AMP-dependent protein kinase activity in cytosolic extracts revealed distinct sites of phosphorylation (Schulman, H., 1984, Mol. Cell. Biol., 4:1175-1178; abstract by me and J.A. Kuret and K.H. Spitzer [1983, Fed. Proc., 42:2250]. I have now used MAP-2 as a substrate to purify the Ca2+/calmodulin-dependent protein kinase responsible for MAP-2 phosphorylation. The brain appears to contain a single predominant Ca2+/calmodulin-dependent protein kinase that phosphorylates MAP-2. The enzyme was purified to apparent homogeneity by column chromatography using DEAE-cellulose, phosphocellulose, hydroxylapatite, Sepharose 6B, and a calmodulin-Sepharose affinity column. The 580,000-dalton holoenzyme consists of 51,000- and 60,000-dalton subunits. The purified enzyme phosphorylates MAP-2 at the same "sites" that are phosphorylated in cytosolic extracts and thus has the same specificity as the activity present in cytosol. Analysis of phosphorylated MAP-2.1 and MAP-2.2, the two components of MAP-2, suggests considerable homology in their phosphorylated domains.
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PMID:Phosphorylation of microtubule-associated proteins by a Ca2+/calmodulin-dependent protein kinase. 673 24

Induction of long-term potentiation in the CA1 region of hippocampal slices is associated with increased activity of Ca2+/calmodulin-dependent protein kinase II (CaM kinase II) (Fukunaga, K., Stoppini, L., Miyamoto, E., and Muller, D. (1993) J. Biol. Chem. 268, 7863-7867). Here we report that application of high but not low frequency stimulation to two groups of afferents in the CA1 region of 32P-labeled slices resulted in the phosphorylation of two major substrates of this enzyme, synapsin I and microtubule-associated protein 2, as well as in the autophosphorylation of CaM kinase II. Furthermore, immunoblotting analysis revealed that long term potentiation induction was associated with an increase in the amount of CaM kinase II in the same region. All these changes were prevented when high frequency stimulation was applied in the presence of the N-methyl-D-aspartate receptor antagonist, D-2-amino-5-phosphonopentanoate. These results indicate that activation of CaM kinase II is involved in the induction of synaptic potentiation in both the postsynaptic and presynaptic regions.
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PMID:Increased phosphorylation of Ca2+/calmodulin-dependent protein kinase II and its endogenous substrates in the induction of long-term potentiation. 789 Jul 45


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