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)

Calcium ion (Ca2+) is considered to be involved in the regulation of numerous cellular processes. CaM kinase II is present at the highest concentration in the brain and is considered to be involved in the regulation and coordination of numerous cellular processes. CaM kinase II is activated by Ca2+/calmodulin and simultaneously undergoes autophosphorylation. It has not been determined whether the enzyme is activated in the cell systems in response to the increase in cytoplasmic Ca2+ concentration. We have studied CaM kinase II in several kinds of cells including the primary cultures of cerebellar granule cells and the cell lines of rat embryo fibroblast 3Y1 cells, neuroblastoma cells, PC12 cells and C6 glioma cells. The immunohistochemical analysis demonstrated the presence of CaM kinase II in all of the cells examined. Furthermore, the kinase in cerebellar granule cells was activated by the stimulation of the glutamic acid receptor. Autophosphorylation of CaM kinase II in 3Y1 cells was stimulated by the addition of growth factors. These results suggest that CaM kinase II undergoes activation and autophosphorylation in response to various stimuli to the cells and is regulated in the dynamic state.
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PMID:[Regulation of Ca2+/calmodulin-dependent protein kinase II in the cell systems in response to cellular stimuli]. 166 Apr 42

The regulatory role of Arg283 in the autoinhibitory domain of Ca2+/calmodulin-dependent protein kinase II was investigated using substituted inhibitory synthetic peptides and site-directed mutation of the expressed kinase. In the synthetic peptide corresponding to the autoinhibitory domain (residues 281-309) of Ca2+/calmodulin-dependent protein kinase II, substitution of Arg283 by other residues increased the IC50 values of the peptides in the following order: Arg much less than Lys much less than Gln much less than Glu. Site-directed mutations of Arg283 to glutamic acid and glutamine in the kinase alpha subunit cDNA were transcribed and translated in vitro. The expressed enzymes had the same total kinase activities, determined in the presence of Ca2+/CaM, but the Glu283 mutant had a slightly higher Ca2(+)-independent kinase activity (5.46 +/- 0.88%) compared to the wild-type Arg283 (1.86 +/- 0.71%) and the Gln283 mutant (2.15 +/- 0.60%). When the expressed kinases were subjected to limited autophosphorylation on ice to monitor generation of the Ca2(+)-independent activity, the Arg283 kinase attained maximal Ca2(+)-independent activity (about 20%) within 30 s, whereas the Gln283 and Glu283 mutants attained maximal Ca2(+)-independence only after about 40 min of autophosphorylation. The results indicate that Arg283 is a very important determinant for the regulatory autophosphorylation of Thr286 that generates the Ca2(+)-independent activity but is not essential for the other multiple autophosphorylations within Ca2+/calmodulin-dependent protein kinase II, and that Arg283 is only one of several important residues for the inhibitory potency of the autoinhibitory domain.
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PMID:Studies on the regulatory domain of Ca2+/calmodulin-dependent protein kinase II. Functional analyses of arginine 283 using synthetic inhibitory peptides and site-directed mutagenesis of the alpha subunit. 197 5

Calspermin is a heat-stable, acidic calmodulin-binding protein predominantly found in mammalian testis. The cDNA representing the rat form of this protein has been cloned from a rat testis lambda gt11 library. Sequence analysis of two overlapping clones revealed a 232-nucleotide 5'-nontranslated region, 510 nucleotides of open reading frame, a 148-nucleotide 3'-untranslated region, and a poly(A) tail. Authenticity of the clones was confirmed by comparison of a portion of the deduced amino acid sequence with the sequence of a tryptic peptide obtained from the rat testis protein. The lambda gt11 fusion protein was recognized by affinity purified antibodies to pig testis calspermin and bound 125I-calmodulin in a Ca2+-dependent manner. Calspermin cDNA encodes a 169-residue protein with a calculated Mr of 18,735. The putative calmodulin-binding domain is very close to the amino terminus of the protein. This region shows 46% identity with the calmodulin-binding region of rat brain Ca2+/calmodulin-dependent protein kinase II and 32% identity with the equivalent region of chicken smooth muscle myosin light chain kinase. The 5'-nontranslated region reveals significant homology with a portion of the catalytic region of the calmodulin-dependent protein kinase family. Calspermin contains a stretch of 17 contiguous glutamic acid residues in the central region of the molecule. Computer analysis predicts calspermin to be 81% alpha-helix and 14% random coil. Analysis of genomic DNA indicates calspermin to be the product of a unique gene. Northern blot analysis of rat testis RNA reveals a 1.1-kilobase mRNA. This RNA is restricted to testis among several rat tissues examined and could not be identified in total RNA isolated from testes of other mammals. Analysis of cells isolated from rat testis reveals calspermin mRNA to be predominantly expressed in postmeiotic cells indicating that it may be specific to haploid cells.
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PMID:Molecular cloning sequence and distribution of rat calspermin, a high affinity calmodulin-binding protein. 291 93

Chicken gizzard smooth muscle contains two major calmodulin-binding proteins: caldesmon (11.1 microM; Mr 141 000) and myosin light-chain kinase (4.6 microM; Mr 136 000), both of which are associated with the contractile apparatus. The amino acid composition of caldesmon is distinct from that of myosin light-chain kinase and is characterized by a very high glutamic acid content (25.5%), high contents of lysine (13.6%) and arginine (10.3%), and a low aromatic amino acid content (2.4%). Caldesmon lacked myosin light-chain kinase and phosphatase activities and did not compete with either myosin light-chain kinase or cyclic nucleotide phosphodiesterase (both calmodulin-dependent enzymes) for available calmodulin, suggesting that calmodulin may have distinct binding sites for caldesmon on the one hand and myosin light-chain kinase and cyclic nucleotide phosphodiesterase on the other. Consistent with the lack of effect of caldesmon on myosin phosphorylation, caldesmon did not affect the assembly or disassembly of myosin filaments in vitro. As previously shown [Ngai & Walsh (1984) J. Biol. Chem. 259, 13656-13659], caldesmon can be reversibly phosphorylated. The phosphorylation and dephosphorylation of caldesmon were further characterized and the Ca2+/calmodulin-dependent caldesmon kinase was purified; kinase activity correlated with a protein of subunit Mr 93 000. Caldesmon was not a substrate of myosin light-chain kinase or phosphorylase kinase, both calmodulin-activated protein kinases.
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PMID:Properties of caldesmon isolated from chicken gizzard. 299 32

Tyrosine-specific protein kinase (ATP:protein phosphotransferase, EC 2.7.1.37) activity was measured in normal human nonadherent peripheral blood lymphocytes using synthetic peptide substrates having sequence homologies with either pp60src or c-myc. A high level of tyrosine-specific protein kinase activity was found associated with the cell particulate fraction (100 000 X g pellet). High-pressure liquid chromatography and phosphoamino acid analysis of the synthetic peptide substrates substantiated the phosphorylation of tyrosine residues by the particulate fraction enzyme. The human enzyme was also capable of phosphorylating a synthetic random polymer of 80% glutamic acid and 20% tyrosine. Enzyme activity was half-maximal with 22 microM Mg X ATP and had apparent Km values for the synthetic peptides from 1.9 to 7.1 mM. The enzyme preferred Mg2+ to Mn2+ for optimal activity and was stimulated 2-5-fold by low levels (0.05%) of some ionic as well as non-ionic detergents including deoxycholate, Nonidet P-40 and Triton X-100. The enzyme activity was not stimulated by N6;O2'-dibutyryl cyclic AMP (100 microM), N6;O2'-dibutyryl cyclic GMP (100 microM), Ca2+ (200 microM), insulin (1 microgram/ml) or homogeneous human T-cell growth factor (3 micrograms/ml) under the conditions used. Alkaline-resistant phosphorylation of particulate proteins in vitro revealed protein bands with Mr 59 000 and 54 000 suggesting that there are endogenous substrates for the human lymphocyte tyrosine protein kinase.
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PMID:High tyrosine-specific protein kinase activity in normal human peripheral blood lymphocytes. 403 88

A 20.5 kb DNA fragment from the left arm of chromosome XI of Saccharomyces cerevisiae has been sequenced and analysed. Thirteen open reading frames (ORFs) for proteins longer than 100 amino acids were discovered. Among them, two are the known genes MRP49 and TPK3; two others encode proteins which show strong similarity with a yeast putative protein kinase and a yeast choline transport protein; one other shows weaker similarity with a yeast Ca2+/calmodulin-dependent protein kinase. Moreover, two putative proteins encoded by ORFs located in the sequenced fragment are closely similar to non-yeast proteins: the Caenorhabditis elegans elongation factor 2 and a glutamic acid-rich protein of Plasmodium falciparum.
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PMID:Sequencing and analysis of a 20.5 kb DNA segment located on the left arm of yeast chromosome XI. 809 58

Isoforms of calcium/calmodulin-dependent protein kinase II from Drosophila (R1-R6 and R3A) showed differential activation by two series of mutant calmodulins, B1K-B4K and B1Q-B4Q. These mutant calmodulins were generated by changing a glutamic acid in each of the four calcium binding sites to either glutamine or lysine, altering their calcium binding properties. All mutations produced activation defects, with the binding site 4 and B1Q mutants the most severe. Activation differed substantially between isoforms. R4, R5, and R6 were the least sensitive to mutations in calmodulin, while R1, R3, and R3A were the most sensitive. Activation of R1 and R2 by B4K and activation of R3 and R3A by B2K and B2Q produced significant (6-fold and almost 3-fold, respectively) differences in Kact between isoforms that differ structurally by a single amino acid. These differences could not be accounted for by differential binding, as all isoforms showed almost identical binding patterns with the mutants. High binding affinity did not always correlate with ability to increase enzyme activity, implying that activation occurs in at least two steps. The isoform-specific differences seen in this study reflect a role for the COOH-terminal variable region in activation of CaM kinase II.
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PMID:Functional diversity of alternatively spliced isoforms of Drosophila Ca2+/calmodulin-dependent protein kinase II. A role for the variable domain in activation. 870 94

The multifunctional calcium/calmodulin-dependent protein kinase II, CaMKII, has been shown to regulate chloride movement and cellular function in both excitable and non-excitable cells. We show that the plasma membrane expression of a member of the ClC family of Cl(-) channels, human CLC-3 (hCLC-3), a 90-kDa protein, is regulated by CaMKII. We cloned the full-length hCLC-3 gene from the human colonic tumor cell line T84, previously shown to express a CaMKII-activated Cl(-) conductance (I(Cl,CaMKII)), and transfected this gene into the mammalian epithelial cell line tsA, which lacks endogenous expression of I(Cl,CaMKII). Biotinylation experiments demonstrated plasma membrane expression of hCLC-3 in the stably transfected cells. In whole cell patch clamp experiments, autonomously active CaMKII was introduced into tsA cells stably transfected with hCLC-3 via the patch pipette. Cells transfected with the hCLC-3 gene showed a 22-fold increase in current density over cells expressing the vector alone. Kinase-dependent current expression was abolished in the presence of the autocamtide-2-related inhibitory peptide, a specific inhibitor of CaMKII. A mutation of glycine 280 to glutamic acid in the conserved motif in the putative pore region of the channel changed anion selectivity from I(-) > Cl(-) to Cl(-) > I(-). These results indicate that hCLC-3 encodes a Cl(-) channel that is regulated by CaMKII-dependent phosphorylation.
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PMID:Regulation of human CLC-3 channels by multifunctional Ca2+/calmodulin-dependent protein kinase. 1127 66

Glutamate produces a hyperpolarizing postsynaptic potential in ON bipolar cells by binding to the metabotropic receptor mGluR6 and subsequently closing a cation-selective channel. It has been proposed that Ca(2+) influx through the cation channel triggers a depression of the synaptic potential. Here we report that this Ca(2+)-mediated depression requires activation of calcineurin, a Ca(2+)/calmodulin-regulated phosphatase. We measured glutamate-evoked currents (I(glu)) with whole cell recordings of ON bipolar cells in light-adapted retinal slices. Depression of I(glu) by Ca(2+) was prevented by inhibitors of calcineurin or by tightly buffering Ca(2+) with bis-(o-aminophenoxy)-N,N,N',N'-tetraacetic acid (BAPTA). However, when cells were dialyzed with BAPTA and a Ca(2+)-independent form of calcineurin (CaN420), depression of I(glu) was restored. Similarly, CaN420 induced depression of I(glu) during continuous glutamate application, a protocol that ordinarily prevents depression. Analysis of changes in the amplitude of the cation-selective current (I(cat)) of cells that were dialyzed with high Ca(2+) (1 microM), or with BAPTA and CaN420, indicates that Ca(2+) depresses I(glu) by reducing I(cat) and that calcineurin acts via the same mechanism. Ca(2+)-mediated depression of I(glu) was not found to involve CaMKII, as inhibitors of CaMKII did not prevent this depression nor did they affect the sensitivity of the response to small changes in the concentration of mGluR6 agonist. Our data suggest that Ca(2+) and calcineurin may play an adaptive role at the synapse between photoreceptor and ON bipolar cells, closing postsynaptic cation channels that are opened by a drop in synaptic glutamate levels during prolonged photoreceptor illumination.
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PMID:Regulation of the retinal bipolar cell mGluR6 pathway by calcineurin. 1220 31

Purkinje cell protein 4-like 1 (Pcp4l1) is a small neuronal IQ motif protein closely related to the calmodulin-binding protein Pcp4/PEP-19. PEP-19 interacts with calmodulin via its IQ motif to inhibit calmodulin-dependent enzymes and we hypothesized Pcp4l1 would have similar properties. Surprisingly, full-length Pcp4l1 does not interact with calmodulin in yeast two-hybrid or pulldown experiments yet a synthetic peptide constituting only the IQ motif of Pcp4l1 binds calmodulin and inhibits calmodulin-dependent kinase II. A nine-residue glutamic acid-rich sequence in Pcp4l1 confers these unexpected properties. This element lies outside the IQ motif and its deletion or exchange with the homologous region of PEP-19 restores calmodulin binding. Conversion of a single isoleucine (Ile36) within this motif to phenylalanine, the residue present in PEP-19, imparts calmodulin binding onto Pcp4l1. Moreover, only aromatic amino acid substitutions at position 36 in Pcp4l1 allow binding. Thus, despite their sequence similarities PEP-19 and Pcp4l1 have distinct properties with the latter harboring an element that can functionally suppress an IQ motif. We speculate Pcp4l1 may be a latent calmodulin inhibitor regulated by post-translational modification and/or co-factor interactions.
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PMID:Pcp4l1 contains an auto-inhibitory element that prevents its IQ motif from binding to calmodulin. 2245 99


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