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

Signal-response coupling was studied in an exocrine female accessory sex gland (albumen gland) of the freshwater snail Lymnaea stagnalis. Glands were incubated in vitro with Calfluxin (CaFl), a neuropeptide which stimulates the influx of Ca2+ into the mitochondria of the secretory cells. This influx, which is considered to reflect an increase of Ca2+ in the cytosol, was measured as the percentage mitochondria containing Ca deposits. Ca deposits. Ca deposits were visualized at the ultrastructural level with the pyroantimonate precipitation technique. The origin of the Ca2+ and the mechanism by which the Ca2+ concentration in the cytosol is elevated were investigated. The results indicate that CaFl stimulates the influx of extracellular Ca2+ and mobilizes intracellular Ca2+. The increase of the percentage of mitochondria containing Ca deposits is sensitive to Ca2+ channel blockers (D600, Co2+, La3+), indicating that Ca2+ channels are involved. Li+ ions suppress the CaFl response, which suggests that the hydrolysis of phosphatidylinositol-4,5-bisphosphate (PIP2), and thus the production of myo-inositol-1,4,5-trisphosphate (IP3) and 1,2-diacylglycerol (DG) is involved in the Ca2+ mobilization. The protein kinase-C (PKC) stimulator 4-beta-phorbol 12-beta-myrastate 13-alpha-acetate (PMA) mimicked the response to CaFl. The PKC inhibitors trifluoperazine (TFP) and chlorpromazine (CP) markedly decreased the CaFl-stimulated influx of Ca2+ into the mitochondria. The PMA-stimulated influx of Ca2+ into the mitochondria is not dependent on extracellular Ca2+ and is not sensitive to Ca2+ channel blockers. In PMA-stimulated glands, the Na+/H+ exchange blocker amiloride completely abolished the Ca2+ influx into mitochondria. In CaFl-stimulated glands the influx was partly blocked. Increasing the internal pH of the glandular cells with the Na+/H+ ionophore monensin or with NH4Cl mimicked the CaFl response. It is proposed that upon stimulation with CaFl, mobilization of intracellular Ca2+ is mediated via the PKC-stimulated activation of the Na+/H+ exchange, thus leading to an increase of the internal pH. The role of IP3 in the mobilization of intracellular Ca2+ is uncertain.
Gen Comp Endocrinol 1988 May
PMID:The role of IP3, PKC, and pHi in the stimulus-response coupling of calfluxin-stimulated albumen glands of the freshwater snail Lymnaea stagnalis. 283 78

Protein kinases I (PK I) and II (PK II) were purified 253- and 13.5-fold, respectively, from an extract of sonically disrupted cells of Legionella micdadei by ion-exchange chromatography on QAE-Sephadex, by histone affinity chromatography, and by HPLC-gel filtration chromatography. Both enzymes catalysed the phosphorylation of calf thymus histones, with a Km of 2.7 mg ml-1 for PK I and 2.9 mg ml-1 for PK II. Histone H2b was the best protein kinase substrate for both PK I and PK II. The pH optima were 6.8 and 7.0 for PK I and PK II respectively. The Km for ATP was 0.29 mM for PK I and 0.33 mM for PK II. PK II activity was stimulated by either cAMP or cGMP, whereas PK I was inhibited by both cyclic nucleotides. The activity of PK I was unaffected by addition of calmodulin, diacylglycerol and mixtures of Ca2+ and acidic phospholipids, but these additions increased PK II activity threefold. The activity of PK II was stimulated by spermine and spermidine, but PK I was inhibited by these compounds. PK I and PK II were both strongly inhibited by heparin.
J Gen Microbiol 1988 May
PMID:Demonstration of two protein kinases in extracts of Legionella micdadei. 284 25

Protein kinase has been extracted in soluble form from virions of pseudorabies virus using 10% NP40, 0.6 M-NaCl. Chromatographic analysis of the extract on DEAE-cellulose and on phosphocellulose showed it to contain more than one kinase. The activity responsible for the phosphorylation of the major phosphoproteins (mol. wts. 120 000, 115 000 and 72 000) of virions was found to be similar in its properties to the host enzyme casein kinase II. Purified casein kinase II from ascites cells or from pig liver was able to phosphorylate heat-inactivated virions. In addition to the major phosphoproteins, active virion preparations were able to phosphorylate a minor low molecular weight phosphoprotein, incorporation into which could be stimulated by the addition of cyclic AMP to the assay. Purified host cyclic AMP-dependent protein kinase also phosphorylated this protein in heat-inactivated virions. Analysis of herpes simplex virus type 1 showed that the major phosphoproteins (VP12 and VP23) could be phosphorylated in heat-inactivated virions by added casein kinase II. One of these (VP12) together with a further minor phosphoprotein (VP14) could be phosphorylated by cyclic AMP-dependent protein kinase.
J Gen Virol 1985 Apr
PMID:Protein kinase activities associated with the virions of pseudorabies and herpes simplex virus. 298 12

The structural proteins L and NS of vesicular stomatitis virus were obtained from purified viral ribonucleoprotein complex followed by phosphocellulose column chromatography and assayed for protein kinase activity using [gamma-32P]ATP as the phosphate donor. The fractions containing purified L protein phosphorylated NS protein in vitro. 8-Azido-ATP, a photoreactive analogue of ATP, was also used as the phosphate donor for phosphorylation of NS protein by the L protein. In the presence of ultraviolet light, only L protein was specifically cross-linked with 8-azido-[gamma-32P]ATP. In the absence of u.v. light 8-azido ATP did no inhibit RNA transcription in a reconstituted reaction or substitute ATP for RNA synthesis in vitro. The above results, taken together, suggest that 8-azido-ATP was bound to the kinase site and phosphorylation of NS protein was mediated by the L protein. Exogenous phosphate acceptor proteins such as phosvitin and casein were also phosphorylated by the L protein fraction. However, addition of an excess of phosvitin failed to compete with the phosphorylation of NS by L, indicating that the protein kinase activity possessed higher affinity for NS. The phosphorylation of NS was strongly inhibited by photoreaction of L protein with 8-azido-ATP with concomitant inhibition of transcription in vitro. These results suggest that phosphorylation of NS protein by L may have a role in the regulation of the virus genome transcription in vitro.
J Gen Virol 1985 May
PMID:In vitro phosphorylation of NS protein by the L protein of vesicular stomatitis virus. 298 94

Two proteins, termed P85gag-mos and P58gag, are encoded by the temperature-sensitive transformation mutant, ts110 Moloney murine sarcoma virus (MuSV). Based on temperature-shift studies, P85gag-mos is believed to be important for the transforming potential of ts110 MuSV and has been found to be associated with a thermolabile kinase activity that phosphorylates both P85gag-mos and P58gag in immune complexes. Modifications of the original kinase assay conditions are reported here that have allowed a 30-fold increase in the specific activity of P85gag-mos phosphorylated in vitro. The in vitro P85gag-mos-phosphorylating activity was found to be unresponsive to 10 microM-cAMP or 10 microM-cGMP. Addition of 1 mM-pyrophosphate, a known phosphatase inhibitor, to the reaction mixture resulted in an increased yield of phosphorylated P85gag-mos and P58gag; the molar phosphate incorporation per mole of P85gag-mos increased from 0.032 to 0.9, whereas the specific activity of in vitro-phosphorylated P58gag increased 18-fold, from 0.013 to 0.234. pH curves of the in vitro kinase reaction further confirmed the presence of phosphatase activity; in the absence of pyrophosphate, a sharp optimum at pH 4 to 5 was observed, whereas it shifted broadly to pH 7.0 in the presence of pyrophosphate. Under the latter conditions, several experiments were performed in order to determine if the kinase was associated with either gag or mos sequences of P85gag-mos. Antisera directed against p15, p12 and p30 sequences of the gag protein region of P85gag-mos yielded immune complexes that allowed phosphorylation in vitro of P85gag-mos. No phosphorylating activity was detected in immune complexes containing MuSV-124-encoded P62gag. An anti-mos serum generated against a synthetic peptide representing the predicted v-mos amino acid residues 37 to 55 recognizes P85gag-mos and allowed phosphorylation of P85gag-mos in vitro in the absence of P58gag. Peptide mapping of both phosphorylated P85gag-mos and P58gag, by using a combination of Cleveland and Western/immunoperoxidase techniques, demonstrated that P85gag-mos became phosphorylated not only on gag sequences, but also at the N-terminal portion of v-mos. Phosphoamino acid analyses of P85gag-mos and P58gag phosphorylated in vitro under these modified conditions yielded predominantly phosphoserine and lesser amounts of phosphothreonine. Metabolically 32P-labelled P85gag-mos and P58gag were also found to contain phosphoserine and phosphothreonine. Based on these results, we conclude that a cAMP-independent, serine/threonine protein kinase activity is associated with the mos sequences of P85gag-mos.
J Gen Virol 1985 Oct
PMID:A cAMP-independent serine/threonine kinase activity is associated with the mos sequences of ts110 Moloney murine sarcoma virus-encoded P85gag-mos. 299 51

The pituitary of goitrogen-treated White Leghorn cockerels is smaller in size than control birds and the pituitaries of castrated cockerels is nearly twice the size of control birds. The pituitary cells generated by these treatments may not be functional thyrotrophs or gonadotrophs and may not be able to respond to their usual stimuli. Low ambient temperature is a well-known stimulus to the thyroid gland acting through pituitary TSH. Cyclic-AMP-dependent protein kinase activity levels are used here as an index of cellular activity in the pituitary and thyroid glands. Castrated cockerels with or without methimazole treatment do not have an increased pituitary cAMP-dependent protein kinase activity in cold. Methimazole-treated birds have an exaggerated pituitary protein kinase response to cold stress when compared with controls. Pituitary cAMP-dependent protein kinase activity is paralleled by a similar activity increase in the thyroid gland of methimazole-treated cockerels and no increase in the thyroid of castrated birds. Castrated birds at all temperatures have an elevated thyroid cAMP-dependent protein kinase activity ratio which is interpreted as the result of removal of testosterone inhibition.
Gen Comp Endocrinol 1985 Dec
PMID:The effects of castration and/or methimazole feeding on the pituitary response to temperature extremes by cockerels. 300 Aug 64

Addition of glucose to acetate-grown cells of Saccharomyces cerevisiae caused a rapid transient increase in the cAMP level followed by a 10-fold, transient increase in the activity of trehalase. Ethidium bromide and acridine analogues inhibited both glucose-induced responses in a similar way, confirming the role of the cAMP signal as the second messenger in the sugar-induced activation of trehalase. When nitrogen sources or protein synthesis inhibitors were added after the transient glucose-induced increase in the trehalase activity, a rapid reactivation of trehalase occurred. In this case, however, there was only a very small increase in the cAMP level, which appeared to be insignificant. When the nitrogen source or the protein synthesis inhibitor was added together with glucose, the trehalase activity remained high for a much longer time also without a significant effect on the cAMP level. When a membrane depolarizing agent was added together with the glucose, both the trehalase activity and the cAMP level remained high. Reversibility experiments in which trehalase was activated to different degrees also showed that for high sugar-induced trehalase activation a high cAMP level is needed, while nitrogen sources stimulate trehalase activity without affecting cAMP levels. In cell extracts, both cAMP and cGMP were able to activate trehalase, the latter however only at 10-fold higher concentrations. The cGMP level in vivo was about 10-fold lower than the cAMP level and was not significantly affected by nitrogen sources or protein synthesis inhibitors. Hence, neither cAMP nor cGMP seem to be involved as the second messenger in the stimulating effect of nitrogen sources and protein synthesis inhibitors on trehalase activity in yeast. Since all other evidence obtained here and before strongly points to regulation of trehalase by a 'cAMP-dependent' protein kinase, we suggest that the presence of a nitrogen source in the growth medium of yeast induces the rapid synthesis of an alternative second messenger able to activate this or another protein kinase.
J Gen Microbiol 1985 Dec
PMID:Cyclic AMP and the stimulation of trehalase activity in the yeast Saccharomyces cerevisiae by carbon sources, nitrogen sources and inhibitors of protein synthesis. 300 55

The appearance of a recently described protein kinase activity (virus-induced protein kinase, ViPK) has been studied during infection of hamster fibroblasts with pseudorabies virus or with herpes simplex virus type 1 (HSV-1). An enzyme activity with comparable catalytic properties was induced in both cases, and had broadly similar kinetics of appearance to that of the viral DNA polymerase. The amount of active ViPK detected depended on the multiplicity of infection, and no ViPK was induced after the viruses had been subjected to irradiation with u.v. light. When cells were infected with the tsK mutant of HSV-1, ViPK was induced at the permissive but not at the restrictive temperature. The ViPK preparations obtained from cells infected with each virus differed in chromatographic properties on anion-exchange and gel-permeation resins. These results indicate that expression of the viral genome is required for induction of ViPK. They suggest that the enzyme may be encoded by the viral genome, but do not provide proof of this.
J Gen Virol 1986 Jun
PMID:Characteristics of the induction of a new protein kinase in cells infected with herpesviruses. 301 70

The 28,000 mol. wt. polypeptide (p28) of adult T-cell leukaemia-associated antigen encoded by the 24S defective human T-cell leukaemia virus (HTLV-I) is associated with protein kinase activity. We have determined the nucleotide sequence of this defective HTLV-I provirus and found that it contains a portion of the gag gene (p19 and part of p24), the pX region, and two long terminal repeats, one at each end. The predicted p28 gag-pX fused protein consists of 190 amino acids and its mol. wt. was calculated as 21,055. The results of peptide mapping analysis showing that p28 contains p19 supported the nucleotide sequence data. That p28 was encoded by this defective provirus was also demonstrated by transient expression of p28 polypeptide in COS 7 cells transfected with a recombinant plasmid containing a simian virus 40 early promoter and the p28-coding region of the 24S HTLV-I.
J Gen Virol 1986 Jul
PMID:Structural analysis of p28 adult T-cell leukaemia-associated antigen. 301 50

We investigated the relationship in Saccharomyces cerevisiae between the cell cycle start function, CDC25, and two mutants defining components of the cAMP pathway. The thermolabile adenylate cyclase mutant cyr1-2(ts) is phenotypically similar to the temperature-sensitive mutant cdc25(ts) in that both mutants, when shifted to the restrictive temperature, arrest in G1 of the cell cycle and permit the initiation of meiosis and sporulation. The mutant bcy1 [a lesion resulting in a low level of regulatory (R) subunit and a high level of active, catalytic (C) subunit of the cAMP-dependent protein kinase] suppresses the temperature-sensitive phenotype of cyr1-2(ts) and confers an asporogenous phenotype. We found that cdc25(ts) complemented cyr1-2(ts), and, unlike cyr1-2(ts), was not suppressible by bcy1, demonstrating that CYR1 and CDC25 must encode different functions. Also our results indicate that CDC25 does not encode the R subunit of the cAMP-dependent protein kinase. In addition, although the cdc25(ts)bcy1 double mutant was temperature sensitive like cdc25(ts), we found that the cdc25(ts)bcy1 homozygous diploid was asporogenous like bcy1/bcy1. The inability of the cdc25(ts)bcy1 double mutant to sporulate demonstrated that CDC25 does not encode the C subunit of the cAMP kinase, and indicated that the CDC25 function modulates the cAMP pathway to control meiosis and sporulation. Further, the temperature-sensitive phenotype of the double mutant, and hence the inability of bcy1 to suppress cdc25(ts), suggested that a second CDC25 cell cycle function exists which is independent of the cAMP pathway.(ABSTRACT TRUNCATED AT 250 WORDS)
J Gen Microbiol 1986 May
PMID:Control of the cAMP pathway by the cell cycle start function, CDC25, in Saccharomyces cerevisiae. 302 94


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