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)

We have studied the effect of protein phosphokinase (EC 2.7.1.37; ATP:protein phosphotransferase) and phosphoprotein phosphatase (EC 3.1.3.16; phosphoprotein phosphohydrolase) on reverse transcriptase (RNA-dependent DNA nucleotidyltransferase) activity of Rous sarcoma virus. Protein kinase from Rous sarcoma virus-transformed chick embryo fibroblasts was purified by DEAE-cellulose chromatography, Sephadex gel filtration, and isoelectric focusing. Purified reverse transcriptase from Rouse sarcoma virus was preincubated with protein kinase and ATP under conditions allowing incorporation of phosphate into substrate protein. After the preincubation, reverse transcriptase activity was assayed in the presence of poly(rA).oligo(dT) as template. A 2- to 5-fold increase of reverse transcriptase activity was found after the preincubation of reverse transcriptase with protein kinase and ATP. Incubation of reverse transcriptase with heat-treated, inactive protein kinase and ATP had no effect on transcriptase activity. When the transcriptase preparation was incubated with protein kinase and [gamma-32P]ATP and subsequently purified by chromatography on phosphocellulose and Sephadex gel filtration, significant amounts of 32P-labeled proteins were found in the fractions exhibiting reverse transcriptase activity, suggesting 32P incorporation into transcriptase or transcriptase-associated proteins. A 20-60% decrease of reverse transcriptase activity was observed after incubation of reverse transcriptase with phosphatase. The results suggest that phosphorylative modification of reverse transcriptase may be critical in the regulation of reverse transcriptase-catalyzed DNA synthesis.
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PMID:Protein kinase and its regulatory effect on reverse transcriptase activity of Rous sarcoma virus. 5 72

Sera from certain rabbits bearing Schmidt-Ruppin strain Rous sarcoma virus (RSV)-induced tumors precipitated p60(src) from chicken cells transformed by the homologous virus as well as by other strains [Prague strain RSV, Bryan high-titer strain RSV, and Bratislava 77 strain of avain sarcoma virus (ASV)], the molecular weights (M(r)s) ranging from 60,000 to 64,000. The p60(src) immunoprecipitated from cells transformed by each of these strains incorporated [gamma-(32)P]ATP into the M(r) 53,000 subunit of IgG, though with differing activities. No such protein kinase activity (ATP:protein phosphotransferase, EC 2.7.1.37) was observed when the following immunoprecipitates were used: from uninfected cells, from untransformed cells infected by Rous-associated virus, or from cells transformed by acute leukosis viruses, avian erythroblastosis virus, or myelocytoma virus 29. The kinase reaction had a pH optimum at pH 5.9 and an apparent K(m) for ATP of 4.9 +/- 2 muM, and was dependent on Mg(2+) (K(b) = 46 +/- 12 mM), for which Ca(2+) was no substitute. The kinase was cyclic AMP independent. In order to test whether the protein kinase reaction is directly catalyzed by p60(src), we compared the in vitro temperature sensitivities of the kinase activities from cells infected by transformation-temperature-sensitive mutant and parental wild-type virus. The first-order rate constant for the inactivation of the kinase from extracts of cells infected by the mutant virus was 2-fold greater than that from cells infected by wild-type virus. This result implicates the protein kinase as an enzymatic activity of the src gene product, the p60(src). Concomitant with the loss of the kinase activity by heat inactivation, p60(src) loses 60-70% of its phosphate content. The kinetics of dephosphorylation exactly parallel those for the inactivation of the kinase activity, suggesting that the p60(src) kinase is itself dependent on phosphorylation for its activity.
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PMID:Src Gene product from different strains of avian sarcoma virus: Kinetics and possible mechanism of heat inactivation of protein kinase activity from cells infected by transformation-defective, temperature-sensitive mutant and wild-type virus. 21 25

Three different types of experiments are presented in this paper, the results of which converge to indicate that the viral src protein associates with and modulates the activity and/or the specificity of a serine/threonine protein kinase. Firstly, a 60-kDa protein from extracts of FR3T3 rat fibroblasts transformed by wild-type Rous sarcoma virus (SRD-FR3T3) is shown to be immunoprecipitated with a monoclonal antibody (mAb) raised against bacterially produced pp60v-src, the mAb327 [Lipsich, L. A., Lewis, A. J. & Brugge, J. S. (1983) J. Virol. 48, 352-360] and to be phosphorylated in vitro at serine/threonine/tyrosine residues, in the ratio 25:53:22. Under the same experimental conditions, the pp60c-src protein immunoprecipitated with mAb327 from extracts of NIH c-src overexpresser cells is phosphorylated exclusively on tyrosine residues. Secondly, the results of immunoprecipitation experiments using a tumor-bearing rabbit (TBR) serum and reported in an earlier work [David-Pfeuty, T. & Hovanessian, A. (1984) Eur. J. Biochem. 140, 325-342], together with those reported here, suggest that the TBR-immunoprecipitated pp60v-src coprecipitates with a cellular protein related to the 60-kDa subunit of the Ca2+/calmodulin protein kinase II from brain. Finally, partially purified preparations of pp60v-src, but not of pp60c-src, are shown to contain a Ca2+/calmodulin-dependent protein kinase activity that phosphorylates a 52-kDa protein substrate.
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PMID:Serine/threonine-specific protein kinase activity associated with viral pp60src protein. 216 17

The activation state of cyclic AMP-dependent protein kinase(s)(ATP:protein phosphotransferase, EC 2.7.1.37) is transiently increased 2-fold as a function of G1 progression in mitotically synchronized Chinese hamster ovary cells. The cellular content of type I kinase increases concomitantly with the increase in general protein, whereas the activity of type II kinase increases as a function of time in G1 to a maximum at the G1/S border. In contrast, in the presence of dibutyryl-cyclic AMP, there is a decrease of type II kinase and a several-fold increase of type I kinase. In proliferating cells, the ratio of type I to type II was 0.37, while in the dibutyryl-cyclic AMP growth-arrested cells it was 3.96. The increase in type II kinase during G1 transition and the increase in type I kinase during dibutyryl-cyclic AMP treatment were dependent on protein synthesis. A similar pattern of type I and type II kinase expression during cell cycle progression occurred in Rat-1 fibroblasts and Rat-1 cells transformed by Rous sarcoma virus. The inclusion of dibuityryl-cyclic AMP in the growth media promoted a marked increase in type I holoenzyme, which was inhibited by cycloheximide, and a decrease in type II kinase. Neither AMP nor sodium butyrate had any effect on cellular kinase levels, whereas 8-bromo-cyclic AMP mimicked the action of dibutyryl-cyclic AMP. Estimation of half-lives for the kinase types showed that there was little turnover of either type during normal G1 progression, rapid turnover of both types as cells exited from mitosis, and selective turnover of type II upon addition of dibutyryl-cyclic AMP.
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PMID:Differential expression of type I and type II cyclic AMP-dependent protein kinases during cell cycle and cyclic AMP-induced growth arrest. 615 48

The gag-linked transformation-specific protein (polyprotein) p80 of Esh avian sarcoma virus (ESV) has been compared by tryptic peptide mapping with the homologous protein p90 of Yamaguchi 73 avian sarcoma virus (Y73). p80 of ESV and p90 of Y73 were found to share all four of their major nonstructural, transformation-specific, methionine-containing peptides and to have at least seven cysteine-containing transformation-specific peptides in common. Two nonstructural cysteine-containing peptides unique for ESV p80 and three specific for Y73 p90 were also identified. None of these peptides were found in the transforming gene product pp60src of Rous sarcoma virus (RSV) or in the transformation-specific polyproteins p105 of avian sarcoma virus PRCII (PRCII) or p140 of Fujinami sarcoma virus (FSV). ESV p80 and Y73 p90 are phosphorylated, and their tryptic phosphopeptides appear to be identical. In each polyprotein two major phosphopeptides were demonstrated, one containing phosphoserine, the other phosphotyrosine. The latter serves as phosphoacceptor for the protein kinase activities (ATP:protein phosphotransferase, EC 2.7.1.37) associated with p80 and p90. These protein kinase activities were found to be functionally indistinguishable but could be easily distinguished from the activities associated with PRCII p105 and FSV p140 on the basis of their cation requirement and target site specificity. On that basis also, p80/p90-associated protein kinases were found to be more similar to the enzymatic activity of pp60src than to those associated with the PRCII and FSV transformation-specific polyproteins. These results document a close genetic relationship between the two independently isolated sarcoma viruses Y73 and ESV. On the basis of the relatedness of transformation-specific proteins, ESV and Y73 constitute class III of avian sarcoma viruses, with class I containing the various strains of RSV and class II encompassing FSV and PRCII.
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PMID:A third class of avian sarcoma viruses, defined by related transformation-specific proteins of Yamaguchi 73 and Esh sarcoma viruses. 626 85

In the presence of costimulation, Ca2+ influx in T cells leads to activation (transcription of interleukin-2; ref. 2) via calcineurin. In the absence of costimulation, Ca2+ influx results in anergy (interleukin-2 transcriptional block) through an unknown mechanism. Specific attenuation of interleukin-2 transcriptional induction occurs in Jurkat T cells following pretreatment with a Ca2+ ionophore. A > 90% block of inducible interleukin-2 reporter gene activity was initiated by transfection of a constitutively active mutant of multifunctional Ca2+/calmodulin-dependent protein kinase (CaM kinase or CaM kinase II), but not by constitutive mutants of CaM kinase IV, calcineurin or protein kinase C. The block was complete six hours after kinase transfection and showed specificity for interleukin-2; there was no change in beta-actin transcription or in c-fos transcription induced by phorbol myristyl acetate, and a Rous sarcoma virus promoter was stimulated threefold. Multifunctional CaM kinase also attenuated interleukin-2 activation by calcineurin plus phorbol ester. T-cell receptor signalling activates multifunctional CaM kinase. These findings suggest that two Ca2+/calmodulin-responsive enzymes, multifunctional CaM kinase and calcineurin, could mediate the divergent effects of Ca2+ signals in T-lymphocyte regulation.
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PMID:Interleukin-2 transcriptional block by multifunctional Ca2+/calmodulin kinase. 809 Feb 6

Calcium/calmodulin-dependent protein kinases (CaM kinases) have been reported to be involved in neuroplasticity. We have cloned a new Drosophila CaM kinase gene named caki. We describe the molecular characterization of caki and a behavioral effect of its elimination. The caki gene is extremely large; comparison of the genomic and cDNA sequences reveals that the caki transcription unit is at least 150 kb. The catalytic domain of this new CaM kinase protein shares homology (41%) with type II CaM kinases, while the C-terminal part is divergent. Constitutively expressed Caki protein is enzymatically active since it causes a 3-fold increase in the level of the Rous sarcoma virus long terminal repeat (RSV LTR) promoter in a co-transfusion assay. In situ hybridization shows that during embryogenesis, larval and pupal life, transcription of caki is restricted almost exclusively to the central nervous system. In the adult head, immunohistochemistry reveals Caki protein in the lamina, the neuropil of the medulla, lobula, lobula plate and in the central brain. Mutant caki flies show reduced walking speed in 'Buridan's paradigm'.
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PMID:A new Drosophila Ca2+/calmodulin-dependent protein kinase (Caki) is localized in the central nervous system and implicated in walking speed. 861 33