Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: 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)

In addition to a role for de novo protein synthesis in apoptosis we have previously shown that activation of a protein phosphatase or loss of activity of a kinase is also important in radiation-induced apoptosis in human cells [Baxter, and Lavin (1992): J Immunol 148:149-1954]. We show here that some inhibitors of protein kinases exacerbate radiation-induced apoptosis in the human cell line BM13674. The specific protein kinase A inhibitor isoquinoline sulfonamide (20 microM) gave rise to significantly increased levels of apoptosis at 2-6 h postirradiation compared to values after radiation exposure only. The same concentration of isoquinolinesulfonamide, which was effective in increasing apoptosis, reduced activity markedly. A 66% inhibition of cyclic AMP-dependent protein kinase A activity occurred in unirradiated cells at this concentration of H89 and activity was reduced to 58% in irradiated cells. Calphostin C, a specific inhibitor of protein kinase C, at a concentration of 0.1 microM, which caused 68% inhibition of enzyme activity in irradiated cells, failed to enhance the level of radiation-induced apoptosis. Other kinase inhibitors did not lead to an additional increase in apoptosis over and above that observed after irradiation. The results obtained here provide further support for an important role for modification of existing proteins during radiation-induced apoptosis.
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PMID:Protein kinase A inhibitors enhance radiation-induced apoptosis. 753 51

We investigated the effects of cAMP on the urokinase-type plasminogen activator (uPA) production in human pre-B lymphoma cell line RC-K8 that is consistently secreting uPA in the conditioned medium. Both Bt2cAMP and PGE1 inhibited the uPA accumulation in a dose-dependent manner. Northern blot analysis and nuclear run-on assay revealed that uPA gene transcription was repressed by Bt2cAMP and the repression was negated by inhibition of de novo protein synthesis by cycloheximide. Pretreatment with H89 (N-[2-(p-bromocinnamyl-amino) ethyl]-5-isoquinoline sulfonamide), a specific cAMP-dependent protein kinase (PKA) inhibitor, strongly inhibited both the PKA activation and the supression of uPA mRNA accumulation induced by cAMP. H85 (N-[2-(N-formyl-p-chlorocinnamyl-amino) ethyl]-5-isoquinoline sulfonamide), which closely resembles H89 in its chemical structure but is not a selective inhibitor of PKA, showed little effect on the regulation of uPA gene regulation by Bt2cAMP. These results suggest that cAMP represses uPA gene transcription in human pre-B lymphoma cells through PKA pathway and in which de novo protein synthesis is required.
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PMID:Protein kinase activity-dependent inhibition of urokinase-type plasminogen activator gene transcription by cyclic AMP in human pre-B lymphoma cell line RC-K8. 754 28

Immortal human fibroblasts isolated following transfection with thermolabile simian virus 40 T antigen lost division potential upon shift up in temperature due to heat inactivation of the antigen. Such cells showed a concomitant change in the distribution of a mortality marker, mortalin, from a juxtanuclear cap like distribution of immortal cells to a uniform cytosolic distribution of mortal cells. We made an attempt to modulate the above inducible system of cellular senescence using various protein kinase inhibitors. Among the indolocarbazole type inhibitors tested, only KT5823, defined as a specific inhibitor of cGMP-dependent protein kinase, blocked the loss of division potential as determined by cell growth and colony forming ability. This inhibitor also prevented the above change in mortalin distribution due to temperature shift. In addition, the isoquinoline sulfonamide derivatives H8, H9, H88 and H89, all shown to inhibit cGMP-dependent protein kinase, suppressed the senescence. Inhibitors specific to other types of protein kinases, protein phosphatases or tyrosine kinases tested had no effect. Since there was no difference between the effective and non-effective inhibitors in their effects on cell cycle progression, cell cycle arrest by itself cannot account for the above phenomenon. These results suggest that a signaling pathway possibly mediated by cGMP-dependent protein kinase is involved in the induction of cellular senescence.
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PMID:Inhibitors of cGMP-dependent protein kinase block senescence induced by inactivation of T antigen in SV40-transformed immortal human fibroblasts. 765 25

A brief overview is presented of progress in the development of specific inhibitors of protein kinases CKI and CKII. Two promising classes of inhibitors, which have the ability to traverse cell membranes, are now known. One of these is based on halogenated benzimidazoles and 2-aza-benzimidazoles (benzotriazoles) and some of their nucleosides. The second embraces modified isoquinoline sulfonamides, several of which are known as inhibitors of other protein kinases. Both classes include analogs that permit discrimination between CKI and CKII. Ongoing research with halogenated benzotriazoles leads to inhibitors with Ki values below 1 microM. Also considered are nucleoside triphosphate analog inhibitors and their potential properties as donors, with illustrative examples from the field of nucleoside kinases, including the apparent existence of a dual-specific viral protein/nucleoside kinase. The role of cellular CKII and viral-encoded CKII-like activities in viral replication underlines the potential of CKII inhibitors as antiviral agents, exemplified by the case of vesicular stomatitis virus.
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PMID:Development of inhibitors of protein kinases CKI and CKII and some related aspects, including donor and acceptor specificities and viral protein kinases. 773 15

Staurosporine, an inhibitor of protein kinases, induced outgrowth of cultured embryonic Xenopus myocytes. The outgrowing membrane elicited by staurosporine was stained uniformly with fluorescein isothiocyanate-phalloidin. Pretreatment with microfilament-disrupting agents but not microtubule inhibitors inhibited staurosporine-induced membrane outgrowth. Microfilament assembly is thus required for the action of staurosporine. Protein kinase C activators did not antagonize the membrane outgrowing effect of staurosporine. Furthermore, none of H-7 (1-(5-isoquinolinesulfonyl)-2-methylpiperazine dihydrochloride), H-8 (N[2-(methylamino)ethyl]-5-isoquinoline sulfonamide), sphingosine, phloretin, genistein or calmidazolium induced any significant morphological changes of embryonic myocytes, indicating that tyrosine kinases, protein kinase C, protein kinase A or calmodulin-dependent protein kinases may not be involved in the membrane outgrowing action of staurosporine. Total protein content of myocytes was not altered by staurosporine and protein or RNA synthesis inhibitors did not inhibit the membrane outgrowth induced by staurosporine. Furthermore, membrane outgrowth induced by staurosporine was less pronounced in older cultured myocytes or myocytes acutely isolated at later stages of tadpoles, indicating that there is different developmental susceptibility to the action of staurosporine.
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PMID:Pharmacological evidence for a lack of role for protein kinase C in staurosporine-induced morphological changes in embryonic Xenopus myocytes. 780 81

The involvement of cyclic AMP-dependent protein kinase (PKA) for excitatory action of adenosine on neurotransmission was investigated using superior colliculus slices. The postsynaptic potential was elicited in the superficial gray layer after optic layer stimulation. Application of dibutyryl cyclic AMP to the medium enhanced the postsynaptic potential, but additional application of adenosine at 100 microM did not change the amplitude. Treatment of slices with a non-selective protein kinase inhibitor, 1-(5-isoquinolinesulfonyl)-2-methylpiperazine (H-7) or a selective PKA inhibitor, N-[2-(methylamino)ethyl]-5-isoquinolinesulfonamide (H-8) blocked the excitatory action of adenosine. Forskolin enhanced the postsynaptic potential, which was counteracted by treatment with a highly selective PKA inhibitor, N-[2-(p-bromocinnamylamino)ethyl]-5-isoquinoline sulfonamide (H-89) and subsequent application of 100 microM adenosine did not potentiate the postsynaptic potential. These results indicate that the excitatory effect of adenosine on neurotransmission in the superior colliculus involves PKA system.
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PMID:The contribution of PKA to the excitatory mechanism of adenosine in guinea pig superior colliculus slices. 789 83

We have examined phosphorylation of the rat liver glucocorticoid receptor (GR) and GR-associated protein kinase (PK) activity in the immunopurified receptor preparations. Affinity labeling of hepatic cytosol with [3H]dexamethasone 21-mesylate showed a covalent association of the steroid with a 94 kDa protein. GR was immunopurified with antireceptor monoclonal antibody BuGR2 (Gametchu & Harrison, Endocrinology 114: 274-279, 1984) to near homogeneity. A 23 degrees C incubation of the immunoprecipitated protein A-Sepharose adsorbed GR with [gamma-32P]ATP,Mg2+ and the catalytic subunit of cAMP-dependent PK (cAMP-PK) from bovine heart, led to an incorporation of radioactivity in the 94 kDa protein. Phosphorylation of GR was not evident in the absence of the added kinase. Of the radioinert nucleotides (ATP, GTP, UTP or CTP) tested, only ATP successfully competed with [gamma-32P]ATP demonstrating a nucleotide specific requirement for the phosphorylation of GR. Other divalent cations, such as Mn2+ or Ca2+, could not be substituted for Mg2+ during the phosphorylation reaction. Phosphorylation of GR was sensitive to the presence of the protein kinase inhibitor, H-8, an isoquinoline sulfonamide derivative. In addition, the incorporation of radioactivity into GR was both time- and temperature-dependent. The phosphorylation of GR by cAMP-PK was independent of the presence of hsp-90 and transformation state of the receptor. The results of this study demonstrate that GR is an effective substrate for action of cAMP-PK and that the immunopurified protein A-Sepharose adsorbed GR lacks intrinsic kinase activity but can be conveniently used for the characterization of the phosphorylation reaction in the presence of an exogenous kinase.
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PMID:Phosphorylation of immunopurified rat liver glucocorticoid receptor by the catalytic subunit of cAMP-dependent protein kinase. 796 99

The protein kinases that stimulate ion flux across airway epithelium are believed to utilize ATP as phosphate donor. Here we show that a chloride-sensitive protein kinase (in an apically enriched plasma membrane fraction from human nasal respiratory epithelium) uses guanosine 5'-triphosphate in preference to ATP as phosphate donor and is not inhibited by the protein kinase inhibitors staurosporine, 1-(5-isoquinolinylsulfonyl)-2-methylpiperazine, and N-(2-guanodinoethyl)-5-isoquinoline sulfonamide. This kinase phosphorylates a 37-kDa membrane protein (p37), which exhibits a 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (DIDS)-sensitive phosphorylation peak at 40 mM Cl- (DIDS inhibition constant = 8 microM). p37 is additionally phosphorylated by an N-(2-guanodinoethyl)-5-isoquinoline sulfonamide-inhibitable protein kinase that uses ATP and shows a similar chloride sensitivity. The profile of membrane phosphoproteins generated by both kinases is also dependent on the source of Pi, the species of anion, and the concentration of anion. We propose a molecular mechanism for the transduction of Cl- concentration into a guanosine 5'-triphosphate-selective protein kinase signal and show that anion substitution alters the intensity of phosphorylation of membrane proteins in the absence of exogenously added protein kinases.
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PMID:A novel chloride-dependent GTP-utilizing protein kinase in plasma membranes from human respiratory epithelium. 797 69

Photodynamic therapy (PDT) generates reactive oxygen species which initiate the cytotoxic events of this tumor treatment. We demonstrate that PDT mediated oxidative stress induced a transient increase in the early response genes c-fos, c-jun, c-myc, and egr-1 in murine radiation-induced fibrosarcoma cells. Incubation of exponentially growing cells with porphyrin based photosensitizers in the dark also induced an increase in mRNA levels of early response genes. However, the xanthine photosensitizer, rose bengal, produced increased c-fos mRNA levels only following light treatment. Nuclear runoff experiments confirmed that the induction of c-fos mRNA is controlled in part at the level of transcription. Likewise, a chloramphenicol acetyltransferase reporter construct containing the major c-fos transcriptional response elements was inducible by porphyrin and PDT. Signal transduction pathways associated with PDT mediated c-fos activation were examined by treating cells with protein kinase inhibitors. Staurosporine and 1-(5-isoquinolinesulfonyl)-2-methylpiperazine inhibited PDT mediated c-fos activation while N-(2-guanidinoethyl)-5-isoquinoline-sulfonamide had no effect. In addition, quinacrine, which can inhibit phospholipase activity, blocked PDT induced c-fos mRNA expression. These results suggest that photosensitizer mediated oxidative stress acts through protein kinase-mediated signal transduction pathway(s) to activate early response genes.
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PMID:Photodynamic therapy mediated induction of early response genes. 811 27

The involvement of protein kinase C in differentiation of rat adipocyte precursor cells in serum-free culture was evaluated by using various protein kinase inhibitors. Induction of adipose conversion, which was maximal after 10 days of culture in the presence of 5 micrograms/ml insulin, 10 micrograms/ml transferrin, and 200 pM triiodothyronine, was inhibited by the addition of protein kinase C inhibitors, H-7 and staurosporine, in a dose-dependent fashion with the maximal effect at 10 microM and 10 nM, respectively. Inhibition of adipocyte differentiation by 12-O-tetradecanoylphorbol 13-acetate (10(-8) M), an activator of protein kinase C, was reversed by a concomitant addition of either 10 microM H-7 or 10 nM staurosporine. HA1004, a potent inhibitor of cAMP- and cGMP-dependent protein kinases, with minimal inhibitory activity on protein kinase C, did not affect adipose conversion. Furthermore, H-89, another isoquinoline derivative with a selective inhibitory action on cAMP-dependent protein kinase, was without effect on cellular differentiation. These results indicate that the potentiation of adipogenesis by H-7 and staurosporine is mediated by suppression of protein kinase C and that protein kinase C is involved in adipocyte differentiation in an inhibitory fashion.
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PMID:Protein kinase C inhibitors enhance differentiation of rat adipocyte precursor cells in serum-free culture. 819 22


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