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

Calmodulin-dependent protein kinase IV (CaM-kinase IV) is thought to play crucial roles in the functioning of Ca2+ in the central nervous system and immune system, and the regulation of its activity is therefore very important. Recombinant CaM-kinase IV is invaluable for studies of its regulatory mechanism, because of its large-amount availability and ready site-specific mutagenesis. In the present study, rat CaM-kinase IV was expressed in Sf9 cells and Escherichia coli, and the kinetic properties were examined with syntide-2 and peptide-gamma as substrates. The recombinant enzymes were produced highly efficiently, comprising as much as about 15% of the total protein in Sf9 cells and 9% in E. coli. The brain enzyme shows two Km values for syntide-2 in the presence of Ca2+/calmodulin, but the recombinant enzymes showed normal kinetic behavior. The brain enzyme and Sf9 enzyme showed Km values for peptide-gamma of 53 and 82 microM, respectively, but the Km of the E. coli enzyme was as high as 1.7 mM, in the presence of Ca2+/calmodulin. Thus, the three enzymes differed in their kinetic properties, but all the three were markedly activated upon incubation with CaM-kinase IV kinase under the Ca2+/calmodulin-dependent protein phosphorylation conditions.
 ...
PMID:Comparison of Ca2+/calmodulin-dependent protein kinase IV from rat brain, expressed in insect cells, and expressed in Escherichia coli. 854 71

Efficient transcription and replication of the bovine leukemia virus (BLV) genome require both the viral long terminal repeat (LTR) and the virus-coded transcriptional activator Tax, which functions through a 21-bp sequence (Tax-responsive element [TxRE]) which is repeated three times within the LTR. Since Tax does not bind directly to DNA, host cell transcription factors play a central role in BLV expression. Electrophoretic mobility shift assays with nuclear extracts prepared with infected bovine B lymphocytes revealed five TxRE-specific complexes (C1, C2, C3, C4, and C5). Here, by using a UV-induced indirect labeling technique (UV cross-linking) in conjunction with mobility shift assays, eight major polypeptides of 31, 33, 42, 46, 51, 57, 87, and 119 kDa were identified within these five complexes. Immunoprecipitation experiments identified the 57- and 119-kDa proteins as cyclic AMP response element-binding (CREB) proteins, the 46- and 51-kDa proteins as activating transcription factor-1 (ATF-1), and the 87-kDa as protein ATF-2. All of these proteins (except the ATF-1 protein of 51 kDa) belong to the complex C1, which is the major complex identified in freshly isolated BLV-infected lymphocytes from cattle with persistent lymphocytosis. In transient-cotransfection experiments, these three transcription factors were able to activate LTR-directed gene expression in the presence of protein kinase A or Ca2+/calmodulin-dependent protein kinase IV. CREB protein, ATF-1, and ATF-2 thus appear to be the major transcription factors involved in the early stages of viral expression.
 ...
PMID:The CREB, ATF-1, and ATF-2 transcription factors from bovine leukemia virus-infected B lymphocytes activate viral expression. 862 25

Regulation of calcium transport by sarcoplasmic reticulum provides increased cardiac contractility in response to beta-adrenergic stimulation. This is due to phosphorylation of phospholamban by cAMP-dependent protein kinase or by calcium/calmodulin-dependent protein kinase, which activates the calcium pump (Ca2+-ATPase). Recently, direct phosphorylation of Ca2+-ATPase by calcium/calmodulin-dependent protein kinase has been proposed to provide additional regulation. To investigate these effects in detail, we have purified Ca2+-ATPase from cardiac sarcoplasmic reticulum using affinity chromatography and reconstituted it with purified, recombinant phospholamban. The resulting proteoliposomes had high rates of calcium transport, which was tightly coupled to ATP hydrolysis (approximately 1.7 calcium ions transported per ATP molecule hydrolyzed). Co-reconstitution with phospholamban suppressed both calcium uptake and ATPase activities by approximately 50%, and this suppression was fully relieved by a phospholamban monoclonal antibody or by phosphorylation either with cAMP-dependent protein kinase or with calcium/calmodulin-dependent protein kinase. These effects were consistent with a change in the apparent calcium affinity of Ca2+-ATPase and not with a change in Vmax. Neither the purified, reconstituted cardiac Ca2+-ATPase nor the Ca2+-ATPase in longitudinal cardiac sarcoplasmic reticulum vesicles was a substrate for calcium/calmodulin-dependent protein kinase, and accordingly, we found no effect of calcium/calmodulin-dependent protein kinase phosphorylation on Vmax for calcium transport.
 ...
PMID:Purified, reconstituted cardiac Ca2+-ATPase is regulated by phospholamban but not by direct phosphorylation with Ca2+/calmodulin-dependent protein kinase. 866 79

Calmodulin-dependent protein kinase IV (CaM-kinase IV), which plays crucial roles in the functioning of Ca2+ in the central nervous system and immune system, is markedly activated upon phosphorylation by the action of CaM-kinase IV kinase. Northern and Western blot analyses of CaM-kinase IV kinase showed relatively weak reactions in the rat cerebellum, where the activity of CaM-kinase IV kinase has been demonstrated to exist, indicating that CaM-kinase IV kinase isoforms distinct from the enzyme cloned from the cerebral cortex may exist in the cerebellum. When the crude extracts of rat cerebral cortex, brain stem, and cerebellum were immunotitrated with antibody against the cloned enzyme, only approximately 46, 56, and 25% of the enzyme activity of the respective extracts were immunoprecipitated. Thus, at least two distinct isoforms of CaM-kinase IV kinase appear to exist in the brain.
 ...
PMID:Evidence for the existence of Ca2+/calmodulin-dependent protein kinase IV kinase isoforms in rat brain. 882 55

Endothelial cell (EC) cytoskeletal proteins are one of the earliest primary targets of second messenger cascades generated in response to inflammatory agonists. Actin binding proteins, by modulating actin gelation-solation state and membrane-cytoskeleton interactions, in part regulate cell motility and cell-cell apposition. This in turn can also modulate interendothelial junctional diameter and permeability. Nonmuscle filamin (ABP-280), a dimeric actin-crosslinking protein, promotes orthogonal branching of F-actin and links microfilaments to membrane glycoproteins. In the present study, immunoblot analysis demonstrates that filamin protein levels are low in sparse EC cultures, increase once cell-cell contact is initiated and then decrease slightly at post-confluency. Both bradykinin and ionomycin cause filamin redistribution from the peripheral cell border to the cytosol of confluent EC. Forskolin, an activator of adenylate cyclase, blocks filamin translocation. Bradykinin activation of EC is not accompanied by significant proteolytic cleavage of filamin. Instead, intact filamin is recycled back to the membrane within 5-10 min of bradykinin stimulation. Inhibitors of calcium/calmodulin dependent protein kinase (KT-5926 and KN-62) attenuate bradykinin-induced filamin translocation. H-89, an inhibitor of cAMP-dependent protein kinase, causes translocation of filamin in unstimulated cells. Calyculin A, an inhibitor of protein phosphatases, also causes translocation of filamin in the absence of an inflammatory agent. ML-7, an inhibitor of myosin light chain kinase and phorbol myristate acetate, an activator of protein kinase C, do not cause filamin movement into the cytosol, indicating that these pathways do not modulate the translocation. Pharmacological data suggest that filamin translocation is initiated by the calcium/calmodulin-dependent protein kinase whereas the cAMP-dependent protein kinase pathway prevents translocation. Inflammatory agents therefore may increase vascular junctional permeability by increasing cytoplasmic calcium, which disassembles the microfilament dense peripheral band by releasing filamin from F-actin.
 ...
PMID:Filamin translocation is an early endothelial cell inflammatory response to bradykinin: regulation by calcium, protein kinases, and protein phosphatases. 887 9

Recent evidence indicates that nitric oxide participates in the modulation of vascular tone in a variety of vascular beds, including the parenchymal microvasculature of the brain. The present study examined the role of protein kinase activity in the induction and maintenance of the contractile response when endogenous nitric oxide production is inhibited in parenchymal microvessels of the rat hippocampus. Microvessels in in vitro slices of the hippocampus were monitored using computer-assisted video microscopy. The effects of inhibitors of two kinases, protein kinase C and calcium/calmodulin-dependent protein kinase, on the vasoconstrictor response to NG-nitro-L-arginine (L-NNA) were investigated. The resting luminal diameter of the microvessels examined in this study ranged from 9 to 29 microns. Addition of 100 microM L-NNA to the medium superfusing the slice constricted microvessels by 38.8 +/- 0.6%. The addition of protein kinase inhibitors reversed this constriction in a dose-dependent manner. H-7 (50 microM), a relatively non-selective protein kinase C inhibitor, elicited an 81.4 +/- 10.0% reversal of the L-NNA-induced constriction. Bisindolylmaleimide (5 microM), a selective protein kinase C inhibitor, reversed the constriction by 69.1 +/- 13.7%. KN-62, an inhibitor of calcium/calmodulin-dependent protein kinase II, elicited a smaller yet statistically significant reversal of 17.1 +/- 5.1%. Pretreatment with H-7 or bisindolyl-maleimide blocked the LNNA-induced constriction entirely, while KN-62 did not significantly inhibit the response. These findings indicate that the contractile response observed upon removal of endogenous nitric oxidergic vasodilation is mediated by protein kinase activity, and the contribution of protein kinase C to this effect is greater than that of calcium/calmodulin-dependent protein kinase II. The results suggest that a tonic nitric oxidergic influence serves to mask the potential for protein kinase C-mediated vasoconstriction in cerebral microvessels.
 ...
PMID:Tonic protein kinase C-mediated vasoconstriction is unmasked when nitric oxide synthase is inhibited in cerebral microvessels. 888 87

Myosin heavy chain kinase A (MHCK A) in Dictyostelium was identified as a biochemical activity that phosphorylates threonine residues in the myosin II tail domain and regulates myosin filament assembly. The catalytic domain of MHCK A has now been mapped through the functional characterization of a series of MHCK A truncation mutants expressed in Escherichia coli. A recombinant protein comprising the central nonrepetitive domain of MHCK A (residues 552-841) was isolated in a soluble form and shown to phosphorylate Dictyostelium myosin II, myelin basic protein, and a synthetic peptide substrate. The functionally mapped catalytic domain of MHCK A shows no detectable sequence similarity to known classes of eukaryotic protein kinases but shares substantial sequence similarity with a transcribed Caenorhabditis elegans gene and with the mammalian elongation factor-2 kinase (calcium/calmodulin-dependent protein kinase III). We suggest that MHCK A represents the prototype for a novel, widely occurring protein kinase family.
 ...
PMID:Mapping of the novel protein kinase catalytic domain of Dictyostelium myosin II heavy chain kinase A. 905 68

The existence of isoforms of calmodulin-dependent protein kinase kinase (CaM-kinase kinase) in the rat brain was recently suggested by Northern and Western blot analyses and immunotitration [Okuno, S., Kitani, T., and Fujisawa, H. (1996) J. Biochem. 119, 1176-1181]. In the present study, CaM-kinase kinase beta, distinct from Cam-kinase kinase alpha which had been purified and cloned from rat cerebral cortex, was purified approximately 5,000-fold from rat cerebellum and its properties were examined. The purified CaM-kinase kinase beta gave a doublet at positions corresponding to molecular weights of 66,000 to 67,000 on SDS-PAGE, and neither protein band reacted with antibody against CaM-kinase kinase alpha. Both CaM-kinase kinase alpha and beta markedly activated both CaM-kinase I and IV, but CaM-kinase kinase beta activated CaM-kinase IV more strongly than did CaM-kinase kinase alpha. The maximal extents of the activation of CaM-kinase I and IV by CaM-kinase kinase beta were almost the same as those by CaM-kinase kinase alpha, suggesting that the two CaM-kinase kinases activated CaM-kinase I and IV by the same mechanisms.
 ...
PMID:Purification and characterization of Ca2+/calmodulin-dependent protein kinase kinase beta from rat cerebellum. 905 7

Numerous in vivo studies have demonstrated that psychostimulant drugs such as amphetamine and cocaine can induce the expression of the immediate early gene c-fos in striatal neurons via the activation of D1 dopamine receptors. NMDA receptor activation is also known to induce c-fos in the striatum. In the present study we have used a primary striatal neuronal culture preparation to examine the mechanisms whereby these stimuli lead to changes in gene expression. Direct application of NMDA to striatal cells in culture caused a rapid increase in the expression of c-fos as well as an increase in the phosphorylation of the transcription factor CRE binding protein (CREB). This was prevented by NMDA receptor antagonists, and required extracellular calcium, but did not involve L-type calcium channels. The induction of c-fos and CREB phosphorylation following NMDA were unaffected by inhibition of protein kinase C; tyrosine kinases or nitric oxide synthase. However, the response to NMDA was blocked by KN62, a selective inhibitor of calcium/calmodulin-dependent protein kinase. Application of the D1 agonist SKF 38393, or direct stimulation of adenylyl cyclase with forskolin, also resulted in the phosphorylation of CREB and the induction of c-fos in striatal neurons. These effects were blocked by the protein kinase A inhibitor H89. These observations are consistent with the hypothesis that calcium/calmodulin-dependent phosphorylation of CREB induced by NMDA, or cAMP-dependent phosphorylation of CREB induced by D1 agonists, underlie the induction of c-fos seen following activation of these receptors in striatal neurons.
 ...
PMID:NMDA and D1 receptors regulate the phosphorylation of CREB and the induction of c-fos in striatal neurons in primary culture. 906 20

Tryptophan hydroxylase, the initial and rate-limiting enzyme in the biosynthesis of the neurotransmitter serotonin, is activated by protein kinase A and calcium/calmodulin-dependent protein kinase. One important aspect of the regulation of any enzyme by a phosphorylation-dephosphorylation cascade, and one that is lacking for tryptophan hydroxylase, lies in the identification of its site of phosphorylation by protein kinases. Recombinant forms of brain tryptophan hydroxylase were expressed as glutathione S-transferase fusion proteins and exposed to protein kinase A. This protein kinase phosphorylates and activates full-length tryptophan hydroxylase. The inactive regulatory domain of the enzyme (corresponding to amino acids 1-98) was also phosphorylated by protein kinase A. The catalytic core of the hydroxylase (amino acids 99-444), which expresses high levels of enzyme activity, was neither phosphorylated nor activated by protein kinase A. Conversion of serine-58 to arginine resulted in the expression of a full-length tryptophan hydroxylase mutant that, although remaining catalytically active, was neither phosphorylated nor activated by protein kinase A. These results indicate that the activation of tryptophan hydroxylase by protein kinase A is mediated by the phosphorylation of serine-58 within the regulatory domain of the enzyme.
 ...
PMID:Phosphorylation and activation of brain tryptophan hydroxylase: identification of serine-58 as a substrate site for protein kinase A. 910 52


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>