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

Membrane depolarization of NG108 cells gives rapid (< 5 min) activation of Ca2+/calmodulin-dependent protein kinase IV (CaM-KIV), as well as activation of c-Jun N-terminal kinase (JNK). To investigate whether the Ca2+-dependent activation of mitogen-activated protein kinases (ERK, JNK, and p38) might be mediated by the CaM kinase cascade, we have transfected PC12 cells, which lack CaM-KIV, with constitutively active mutants of CaM kinase kinase and/or CaM-KIV (CaM-KKc and CaM-KIVc, respectively). In the absence of depolarization, CaM-KKc transfection had no effect on Elk-dependent transcription of a luciferase reporter gene, whereas CaM-KIVc alone or in combination with CaM-KKc gave 7- to 10-fold and 60- to 80-fold stimulations, respectively, which were blocked by mitogen-activated protein (MAP) kinase phosphatase cotransfection. When epitope-tagged constructs of MAP kinases were co-transfected with CaM-KKc plus CaM-KIVc, the immunoprecipitated MAP kinases were activated 2-fold (ERK-2) and 7- to 10-fold (JNK-1 and p38). The JNK and p38 pathways were further investigated using specific c-Jun or ATF2-dependent transcriptional assays. We found that c-Jun/ATF2-dependent transcriptions were enhanced 7- to 10-fold by CaM-KIVc and 20- to 30-fold by CaM-KKc plus CaM-KIVc. In the case of the Jun-dependent transcription, this effect was not due to direct phosphorylation of c-Jun by activated CaM-KIV, since transcription was blocked by a dominant-negative JNK and by two MAP kinase phosphatases. Mutation of the phosphorylation site (Thr196) in CaM-KIV, which mediates its activation by CaM-KIV kinase, prevented activation of Elk-1, c-Jun, and ATF2 by the CaM kinase cascade. These results establish a new Ca2+-dependent mechanism for regulating MAP kinase pathways and resultant transcription.
 ...
PMID:Regulation of mitogen-activated protein kinases by a calcium/calmodulin-dependent protein kinase cascade. 885 61

The calmodulin-dependent kinase (CaM-K) cascade, a Ca2+-triggered system involving phosphorylation and activation of CaM-KI and CaM-KIV by CaM kinase kinase (CaM-KK), regulates transcription through direct phosphorylation of transcription factors such as cAMP response element-binding protein. We have shown previously that activated CaM-KIV can activate the mitogen-activated protein kinases (Enslen, H., Tokumitsu, H., Stork, P. J. S., Davis, R. J., and Soderling, T. R. (1996) Proc. Natl. Acad. Sci. U. S. A. 93, 10803-10808), and the present paper describes a novel regulatory cross-talk between cAMP kinase (PKA) and CaM-KK. PKA gave rapid phosphorylation in vitro and in cells of recombinant CaM-KK, resulting in 50-75% inhibition of CaM-KK activity, part of which was due to suppression of CaM-binding by phosphorylation of Ser458 in the CaM-binding domain. However, the Ser458 --> Ala mutant, or a truncation mutant in which the CaM-binding and autoinhibitory domains were deleted, was still partially suppressed by PKA-mediated phosphorylation. The second inhibitory site was identified as Thr108 by site-specific mutagenesis. Treatments of COS-7, PC12, hippocampal, or Jurkat cells with the PKA activators forskolin or isoproterenol gave 30-90% inhibition of either endogenous or transfected CaM-KK and/or CaM-KIV activities. These results demonstrate that the CaM kinase cascade is negatively regulated in cells by the cAMP/PKA pathway.
 ...
PMID:Inhibitory cross-talk by cAMP kinase on the calmodulin-dependent protein kinase cascade. 919 98

Ca2+/calmodulin-dependent protein kinase II (CaM-KII) regulates numerous physiological functions, including neuronal synaptic plasticity through the phosphorylation of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid-type glutamate receptors. To identify proteins that may interact with and modulate CaM-KII function, a yeast two-hybrid screen was performed by using a rat brain cDNA library. This screen identified a unique clone of 1.4 kb, which encoded a 79-aa brain-specific protein that bound the catalytic domain of CaM-KII alpha and beta and potently inhibited kinase activity with an IC50 of 50 nM. The inhibitory protein (CaM-KIIN), and a 28-residue peptide derived from it (CaM-KIINtide), was highly selective for inhibition of CaM-KII with little effect on CaM-KI, CaM-KIV, CaM-KK, protein kinase A, or protein kinase C. CaM-KIIN interacted only with activated CaM-KII (i. e., in the presence of Ca2+/CaM or after autophosphorylation) by using glutathione S-transferase/CaM-KIIN precipitations as well as coimmunoprecipitations from rat brain extracts or from HEK293 cells cotransfected with both constructs. Colocalization of CaM-KIIN with activated CaM-KII was demonstrated in COS-7 cells transfected with green fluorescent protein fused to CaM-KIIN. In COS-7 cells phosphorylation of transfected alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid-type glutamate receptors by CaM-KII, but not by protein kinase C, was blocked upon cotransfection with CaM-KIIN. These results characterize a potent and specific cellular inhibitor of CaM-KII that may have an important role in the physiological regulation of this key protein kinase.
 ...
PMID:Characterization of a calmodulin kinase II inhibitor protein in brain. 972

Mammalian Ca2+/CaM-dependent protein kinase kinase (CaM-KK) has been identified and cloned as an activator for two kinases, CaM kinase I (CaM-KI) and CaM kinase IV (CaM-KIV), and a recent report (Yano, S., Tokumitsu, H., and Soderling, T. R. (1998) Nature 396, 584-587) demonstrates that CaM-KK can also activate and phosphorylate protein kinase B (PKB). In this study, we identify a CaM-KK from Caenorhabditis elegans, and comparison of its sequence with the mammalian CaM-KK alpha and beta shows a unique Arg-Pro (RP)-rich insert in their catalytic domains relative to other protein kinases. Deletion of the RP-domain resulted in complete loss of CaM-KIV activation activity and physical interaction of CaM-KK with glutathione S-transferase-CaM-KIV (T196A). However, CaM-KK autophosphorylation and phosphorylation of a synthetic peptide substrate were normal in the RP-domain mutant. Site-directed mutagenesis of three conserved Arg in the RP- domain of CaM-KK confirmed that these positive charges are important for CaM-KIV activation. The RP- domain deletion mutant also failed to fully activate and phosphorylate CaM-KI, but this mutant was indistinguishable from wild-type CaM-KK for the phosphorylation and activation of PKB. These results indicate that the RP-domain in CaM-KK is critical for recognition of downstream CaM-kinases but not for its catalytic activity (i.e. autophosphorylation) and PKB activation.
 ...
PMID:Substrate recognition by Ca2+/Calmodulin-dependent protein kinase kinase. Role of the arg-pro-rich insert domain. 1033 83

Ca2+/calmodulin-dependent protein kinase IV (CaM-KIV) is thought to be involved in regulating gene expression by phosphorylating various transcriptional factors. CaM-KIV as well as CaM-KI are activated upon phosphorylation by two distinct isoforms of Ca2+/calmodulin-dependent protein kinase kinases, CaM-KKs alpha and beta. In this study, we raised isoform-specific monoclonal antibodies against CaM-KKs and examined the immunohistochemical localization of CaM-KKs in the rat brain, compared with that of CaM-KIV. CaM-KK alpha-immunoreactivity was rather widely distributed in neurons throughout the brain, except cerebellar cortex. The highest levels of CaM-KK alpha-immunoreactivity were observed in the cerebral cortex, facial nucleus and motor neurons of the spinal cord. Moderate CaM-KK alpha-immunoreactivity was observed in the hippocampal formation, pontine nuclei and various brain stem nuclei including trigeminal, vestibular, cochlear and hypoglossal nuclei. In contrast, CaM-KK beta-immunoreactivity was relatively restricted in some neuronal populations. The highest levels of CaM-KK beta-immunoreactivity were observed in the cerebellar granule cell layer, and moderate immunoreactivity was observed in the cerebral cortex, hippocampal formation, caudate putamen, pontine nuclei, cochlear nucleus and molecular layer of the cerebellum. In contrast to the prominent nuclear localization of CaM-KIV, both isoforms of CaM-KKs were localized in the perikaryal cytoplasm, dendrites and nerve terminals, but not in the cell nuclei. The distinct localization of two isoforms of CaM-KKs suggests that the complicated mechanisms for activation of CaM-KIV by CaM-KKs may be exerted in region-specific manners as well as intracellularly.
 ...
PMID:Distinct immunohistochemical localization of two isoforms of Ca2+/calmodulin-dependent protein kinase kinases in the adult rat brain. 1065 63

Recent work from this laboratory both in rat primary cardiomyocytes and in ventricular tissue of transgenic mouse models of induced hypertrophy has identified two Ca(2+)/calmodulin-dependent nuclear signaling cascades. The first involves the phosphatase calcineurin (CaN). The second is the CaM kinase kinase cascade which involves CaM kinase I and CaM kinase IV. Each of these signaling cascades strongly up-regulate transcription of hypertrophy-sensitive genes in the rat ventricular cardiomyocyte. We have documented that over-expression of an active form of CaM kinase II silenced transcriptional induction of hypertrophy-sensitive genes. The purpose of this study was to generate an inducible CaM kinase II expression system and correlate its expression with the silencing of hypertrophic-sensitive reporters. A truncated form of CaM KII, CaM KII (1-290) was subcloned downstream and proximal to a promoter under transcriptional control (induction) of the tetracycline-regulated transcription factor, tet-TransActivator (tTA). Hypertrophy-sensitive reporter activity in primary cardiomyocytes was silenced when tet-inducible CaM KII was co-expressed with plasmids harboring active forms of CaN, CaM KI or CaM KIV. For instance, induced CaM KII expression silenced CaN, CaM kinase I, or CaM kinase IV driven ANF reporter activity 4.9-, 2.9-, and 6.9-fold below their maximal values, respectively. Myocyte exposure to doxycycline (DOX) blocked tTA-driven CaM KII expression and restored CaN/CaM KI or CaN/CaM KIV driven reporter activation. This study demonstrates, for the first time, that active CaM KII silences Ca(2+)-sensitive nuclear signaling cascades for transcriptional up-regulation of cardiomyocyte hypertrophy.
 ...
PMID:Tetracycline-inducible CaM kinase II silences hypertrophy-sensitive gene expression in rat neonate cardiomyocytes. 1092 57

We have reported that the nuclear isoforms of Ca2+/calmodulin-dependent protein kinase II (CaM KII) are involved in the expression of the exon IV-containing brain-derived neurotrophic factor (BDNF) mRNA. We document here the cis-elements and transcription factors responsive to CaM KII in the activation of the promoter upstream of the exon IV (exon IV-BDNF promoter). Effects of constitutively active mutants of CaM KIV, MAPK kinase kinase (MEKK) and protein kinase A (PKA) on the exon IV-BDNF promoter activity were also evaluated by transfection and luciferase assay. The exon IV-BDNF promoter activity was increased by transfection with CaM KII, MEKK and PKA, but not by CaM KIV. Deletion and mutational analysis of the promoter revealed that the region between nucleotides -56 and -27 was responsive to CaM KII, which contained a CCAAT-box in the region between nucleotides -56 and -43. Expression of C/EBPbeta increased the promoter activity and potentiated the effects of CaM KII. The region between nucleotides -79 and -56 was responsive to MEKK, in which both a GA-rich sequence and a GC-box were included. Expression of Sp1 increased the promoter activity, which was further enhanced by transfection with MEKK. The region between nucleotides -43 and -27 was responsive to both PKA and CaM KII, but the transcription factors involved in the region remained unclear. These results suggest that the promoter of the exon IV-BDNF is at least regulated by CaM KII, MEKK and PKA, and that C/EBP/beta and Sp1 are potential transcription factors activated by CaM KII and MEKK, respectively.
 ...
PMID:Analysis on the promoter region of exon IV brain-derived neurotrophic factor in NG108-15 cells. 1235 30

Ca2+/calmodulin-dependent protein kinase IV (CaM-KIV) is phosphorylated at Thr196 by Ca2+/calmodulin-dependent protein kinase kinase (CaM-KK), resulting in induction of both autonomous activity and a high level of Ca2+/CaM-dependent activity. We have shown that the kinetics of Thr196 phosphorylation of CaM-KIV by CaM-KK is well correlated with the generation of its autonomous activity, although Thr177 phosphorylation of CaM-KI does not induce its autonomous activity. The activities of CaM-KI chimera mutants fused with C-terminal regions (residues 296-469 and 296-350) of CaM-KIV are completely dependent on Ca2+/CaM, which is also the case for CaM-KI. Unlike wild-type CaM-KI, however, phosphorylation of Thr177 in the chimera mutants by CaM-KK resulted in generation of significant autonomous activities, indicating that the phosphorylation of Thr in the activation loop is sufficient to partially release the autoinhibitory region of CaM-KIV from the catalytic core. Indeed, the CaM-KIV peptide (residues 304-325) containing minimum autoinhibitory sequences (residues 314-321) suppressed the activity of non-phosphorylated CaM-KIV with an IC50 of approximately 50 microm, and this suppression was competitive with respect to the peptide substrate; however, the CaM-KIV peptide was not capable of inhibiting Thr196-phosphorylated CaM-KIV. Taken together, these results indicated that the Thr196 phosphorylation of CaM-KIV by CaM-KK reduced the interaction of the catalytic core with the autoinhibitory region, resulting in generation of the autonomous activity.
 ...
PMID:Mechanism of the generation of autonomous activity of Ca2+/calmodulin-dependent protein kinase IV. 1526 66

TRH binds to a membrane receptor that activates several intracellular signaling pathways and increases transcription of the TSH and prolactin (PRL) genes. Although TRH induces TSH and PRL gene expression, the underlying mechanism is not clear. In this report we examined the role of the Ca(2+)/calmodulin-dependent protein (CaM) kinase cascade in mediating TRH-stimulated transcription of TSH and PRL. RT-PCR and Western blot analysis were used to show that CaM kinase kinase (CaM-KK) and CaM IV (CaM-KIV) were present in rat anterior pituitary and its cell line GH(3). Next, the effects of constitutively active CaM-KIV (CaM-KIVc) or its dominant negative mutant (CaM-KIVdn) on TSH and PRL promoter activity were tested in GH(3) cells. The results showed that either CaM-KIVc alone or an upstream kinase, CaM-KK, induced the activity of both TSH and PRL promoters. Exposure of GH(3) cells to 100 microm TRH induced CaM-KIV activity within 5 min and, as expected, also increased both TSH and PRL promoter activity. In contrast, cells carrying the CaM-KIVdn isoform had suppressed TRH induction of both TSH and PRL promoter activity. These results indicate that the CaM-KK-CaM-KIV cascade probably plays an important role in TRH induction of TSH and PRL transcriptional activity in pituitary cells.
 ...
PMID:Role of calcium-calmodulin-dependent protein kinase cascade in thyrotropin (TSH)-releasing hormone induction of TSH and prolactin gene expression. 1530 8

Excessive elevation of intracellular calcium level seems to be a trigger of ischemic neuronal injury. Calcium/calmodulin (CaM)-dependent protein kinase kinase (CaM-KK) is an upstream kinase for CaM kinase IV (CaM-KIV) that was reported to prevent apoptosis through phosphorylation of CREB (cyclic AMP responsive element-binding protein). We here observed that CaM-KK could directly activate Akt, thereby preventing apoptosis in cultured cells. Then we examined changes in Akt and CaM-KIV activities in gerbil forebrain ischemia. In 5-min-ischemia-caused delayed neuronal death in hippocampal CA1 neurons, Akt and CaM-KIV activities were decreased after reperfusion. On the other hand, during induction of ischemic tolerance, Akt activity gradually and persistently increased in the CA1 neurons with transient increase in CREB phosphorylation. Inhibition of Akt activity with wortmannin or CREB-DNA binding with CRE-decoy injection resulted in failure of generation of ischemic tolerance. These results indicated activation of Akt and CaM-KIV play important roles in induction of the ischemic tolerance. Activation of CaM-KK may provide a new strategy for overcoming the ischemic stress.
 ...
PMID:Functional proteins involved in regulation of intracellular Ca(2+) for drug development: role of calcium/calmodulin-dependent protein kinases in ischemic neuronal death. 1576 42


1