Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.11.13 (protein kinase C)
 49,245 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effects of inhibition of the basolateral Na(+)-K(+)-ATPase (pump) on the apical low-conductance K+ channel of principal cells in rat cortical collecting duct (CCD) were studied with patch-clamp techniques. Inhibition of pump activity by removal of K+ from the bath solution or addition of strophanthidin reversibly reduced K+ channel activity in cell-attached patches to 36% of the control value. The effect of pump inhibition on K+ channel activity was dependent on the presence of extracellular Ca2+, since removal of Ca2+ in the bath solution abolished the inhibitory effect of 0 mM K+ bath. The intracellular [Ca2+] (measured with fura-2) was significantly increased, from 125 nM (control) to 335 nM (0 mM K+ bath) or 408 nM (0.2 mM strophanthidin), during inhibition of pump activity. In contrast, cell pH decreased only moderately, from 7.45 to 7.35. Raising intracellular Ca2+ by addition of 2 microM ionomycin mimicked the effect of pump inhibition on K+ channel activity. 0.1 mM amiloride also significantly reduced the inhibitory effect of the K+ removal. Because the apical low-conductance K channel in inside-out patches is not sensitive to Ca2+ (Wang, W., A. Schwab, and G. Giebisch, 1990. American Journal of Physiology. 259:F494-F502), it is suggested that the inhibitory effect of Ca2+ is mediated by a Ca(2+)-dependent signal transduction pathway. This view was supported in experiments in which application of 200 nM staurosporine, a potent inhibitor of Ca(2+)-dependent protein kinase C (PKC), markedly diminished the effect of the pump inhibition on channel activity. We conclude that a Ca(2+)-dependent protein kinase such as PKC plays a key role in the downregulation of apical low-conductance K+ channel activity during inhibition of the basolateral Na(+)-K(+)-ATPase.
J Gen Physiol 1993 May
PMID:Mechanism of apical K+ channel modulation in principal renal tubule cells. Effect of inhibition of basolateral Na(+)-K(+)-ATPase. 839 65

The ability of coho salmon gonadotropins GTH I and GTH II to stimulate testicular production of 11-ketotestosterone (11-KT) and 17 alpha,20 beta-dihydroxy-4- pregnen-3-one (17,20 beta-P) in vitro, as well as the involvement of cyclic AMP (cAMP) as a mediator of the actions of GTH I and GTH II, were investigated in maturing male coho salmon. Testicular tissue was incubated in the presence or absence of the test substances at 15 degrees. Both GTH I and GTH II stimulated the in vitro production of 11-KT and 17,20 beta-P in a concentration- and time-dependent manner. In testicular tissue at stage IV of spermatogenesis, GTH I and GTH II stimulated the in vitro production of steroids with similar potency. The steroidogenic activity of GTH I and GTH II appeared to be mediated, at least in part, by cAMP as indicated by the ability of dibutyryl cAMP and forskolin to mimic the steroidogenic actions of GTHs, and the similar ability of GTH I and GTH II to increase intracellular cAMP levels in the testicular tissue. The calcium ionophore A23187 stimulated basal but not GTH-stimulated production of steroids in vitro. In addition, differential effects of a protein kinase C inhibitor, H-7, on 11-KT and 17,20 beta-P production were found. Basal and GTH-stimulated production of 11-KT were inhibited by H-7; whereas basal and GTH-stimulated production of 17,20 beta-P were stimulated by H-7. These results suggest that protein kinase C may also be involved in the steroidogenic actions of GTH I and GTH II.
Gen Comp Endocrinol 1993 Jul
PMID:Regulation of testicular steroid production in vitro by gonadotropins (GTH I and GTH II) and cyclic AMP in coho salmon (Oncorhynchus kisutch). 840 94

Probes derived from cDNAs encoding isozymes of rat protein kinase C (PKC) were used to screen the genome of the budding yeast Saccharomyces cerevisiae. We reported previously the isolation of the yeast PKC1 gene, a homolog of the alpha, beta, and gamma subspecies of mammalian PKC. Here we report the isolation and genetic characterization of a pair of previously described genes (YPK1 and YPK2) which are predicted to encode protein kinases that share 90% amino acid identity with each other and 44-46% identity with various isozymes of PKC throughout their putative catalytic domains. Deletion of YPK2 resulted in no apparent phenotypic defect, but loss of YPK1 resulted in slow growth. Cells deleted for both YPK1 and YPK2 were defective in vegetative growth, indicating that the protein kinases predicted to be encoded by these genes are functionally overlapping and play an essential role in the proliferation of yeast cells. The YPK1 gene was mapped to the left arm of chromosome XI and YPK2 was mapped to the right arm of chromosome XIII.
Mol Gen Genet 1993 Jan
PMID:A pair of putative protein kinase genes (YPK1 and YPK2) is required for cell growth in Saccharomyces cerevisiae. 843 90

A cDNA encoding a serotonin transporter (5-HTT) in the human dorsal raphe nucleus was isolated and sequenced using cross-species amplification of human 5-HTT partial cDNA by the polymerase chain reaction (PCR) and the RACE-PCR procedure, designed for rapid amplification of 3' and 5' cDNA ends. The cDNA contains an open reading frame encoding a hydrophobic polypeptide of 630 amino acids with a calculated molecular weight of approximately 70 kDa. The human 5-HTT is approximately 92% homologous to the rat protein but contains an additional consensus phosphorylation site for cAMP-dependent protein kinase recognition located in the cytoplasmic N-terminal region, while a potential protein kinase C phosphorylation site identified in the rat homolog is not conserved in the human 5-HTT. Hydropathicity analysis revealed twelve membrane spanning segments, a topology proposed for other cloned sodium-dependent transporters.
J Neural Transm Gen Sect 1993
PMID:Isolation of a cDNA encoding the human brain serotonin transporter. 845 85

Oligonucleotides, designed on the basis of conserved flanking amino acid sequence segments within the catalytic domain of eukaryotic protein kinase C (PKC) proteins, were used as primers for polymerase chain reactions to amplify a 427-bp chromosomal DNA fragment from the filamentous fungus Trichoderma reesei. This fragment was then used to isolate genes encoding PKC homologues of T. reesei and Aspergillus niger (pkc1 and pkcA, respectively). The genes contain six (T. reesei) and eight (A. niger) introns, which exhibit notable conservation in position with those found in the corresponding Schizosaccharomyces pombe pkc1+ and Drosophila melanogaster dPKC53Ebr genes. A single 4.2-kb transcript was detected in Northern analyses. The deduced PKC1 (T.reesei, 126 kDa) and PKCA (A. niger, 122 kDa) amino acid sequences reveal domains homologous to the C1 and C3/C4 domains of PKC-related proteins, but lack typical Ca(2+)-binding (C2) domains. Both contain a large, extended N-terminus, which shares a high degree of similarity with the corresponding regions of Saccharomyces cerevisiae PKC1 and S. pombe pkc1+ and pkc2+ proteins, but which is not present in PKCs of Dictyostelium or higher eukaryotes. This extended region can be divided into three subdomains; the N-terminal one contains a hydrophobic helix-turn-helix motif, whereas the C-terminal one contains potential targets for proteolytic processing. A polyclonal antiserum raised against the pseudosubstrate-binding domain of PKC1 recognizes in T. reesei a 115-120 kDa protein in Western blots. Expression of pkc1 cDNA in insect cells directs the synthesis of a PKC1 protein of similar size. The T. reesei PKC1 protein was partially purified and some of its properties examined: it is stimulated about twofold by phospholipids or phorbol esters but is not stimulated by Ca2+. We conclude that these PKC proteins from filamentous fungi represent the Ca(2+)-insensitive fungal homologues of the nPKC family.
Mol Gen Genet 1996 Jan 15
PMID:Cloning and characterisation of genes (pkc1 and pkcA) encoding protein kinase C homologues from Trichoderma reesei and Aspergillus niger. 856 84

We provide evidence to show that the increase in nitrate reductase (NR) transcript level stimulated by red light is mediated via a phosphorylation-dependent step. The light-stimulated enhancement of NR transcript level was significantly inhibited by H-7, a protein kinase inhibitor, whereas okadaic acid (OKA), a phosphatase inhibitor, had no effect. Phorbol myristate acetate (PMA), an activator of protein kinase C (PKC) enhanced the NR transcript level in dark-grown leaves. No correlation between changes in NR transcript level and NR activity (NRA) was observed. Inhibition of NRA by OKA and stimulation by H-7 indicated that NRA is increased by dephosphorylating the enzyme. We have identified a protein kinase (C type) that can phosphorylate the purified NR in vitro without the involvement of other accessory proteins. By in vivo labelling with 32P and immunoprecipitation of NR with NR antibodies it was found that in the presence of OKA most NR protein (NRP) was present in phosphorylated state, while with H-7 the reverse was seen. The red (R) and far-red (FR) light reversible experiments suggested that phytochrome (Pfr, an active form) stimulation of NRA is mediated by dephosphorylation of the enzyme, suggesting that Pfr regulates both NR transcription and NRA via phosphorylation/dephosphorylation steps controlled by separate signal transduction pathways.
Mol Gen Genet 1996 Jul 19
PMID:Phosphorylation/dephosphorylation steps are key events in the phytochrome-mediated enhancement of nitrate reductase mRNA levels and enzyme activity in maize. 870 67

1. Immunoblot experiments in rat prostatic epithelium using a non-selective antibody against protein kinase C (PKC) allowed to detect three PKC subspecies of 87.5, 55.5 and 34.6 kDa that showed higher, similar and lower immunoreactivity in the membrane than in the cytosolic compartment, respectively. 2. Specific monoclonal antisera revealed that the PKC-gamma isozyme is not expressed in the rat prostatic epithelium, whereas the PKC-beta isozyme was noted only in the cytosolic fraction showing an apparent molecular weight of 75.5 kDa. 3. Induction of diabetes by streptozotocin led to modifications in the expression of PKC isozymes so that the immunoreactivities of the 87.5- and 55.5-kDa PKC forms decreased in both cytosolic and membrane subcellular fractions to different extents. 4. The most important decrease was that of the 55.5-kDa PKC form in cytosol that returned to control values by insulin therapy, whereas PKC-beta suffered also some decrease in diabetes and increased again with insulin treatment.
Gen Pharmacol 1995 Dec
PMID:Protein kinase C isozymes in prostatic epithelial cells from normal, diabetic and insulin-treated diabetic rats. 874 55

1. H-7, a protein kinase C inhibitor, fully inhibited the spontaneous and stimulated (KCl 20 mM or histamine 0.5 mM) tone of trachea from normal and sensitized guinea pig. 2. H-7 depressed the concentration-contraction curves to KCl, histamine or 5-hydroxytryptamine in epithelium-denuded, indomethacin-treated, trachea from normal and sensitized guinea pigs while responses to CaCl2 (in Ca2+ -free, K+ -depolarized tissues) and acetylcholine were not affected. 3. H-7 (100 microM did not depress Ca2+ (20 microM-induced contraction of Triton X-100 skinned trachea. 4. These results suggest the involvement of PKC in the maintenance of spontaneous tone and spasmogenic responses of guinea pig trachea.
Gen Pharmacol 1995 Dec
PMID:H-7, a protein kinase C inhibitor, inhibits spontaneous tone and spasmogenic responses in normal and sensitized guinea pig trachea. 874 65

The two-hybrid system for the identification of protein-protein interactions was used to screen for proteins that interact in vivo with the Saccharomyces cerevisiae Pkc1 protein, a homolog of mammalian protein kinase C. Four positive clones were isolated that encoded portions of the protein kinase Mkk1, which acts downstream of Pkc1p in the PKC1-mediated signalling pathway. Subsequently, Pkc1p and the other PKC1 pathway components encoding members of a MAP kinase cascade, Bck1p (a MEKK), Mkk1p, Mkk2p (two functionally homologous MEKs), and Mpk1p (a MAP kinase), were tested pairwise for interaction in the two-hybrid assay. Pkc1p interacted specifically with small N-terminal deletions of Mkk1p, and no interaction between Pkc1p and any of the other known pathway components could be detected. Interaction between Pkc1p and Mkk1p, however, was found to be independent of Mkk1p kinase activity. Bck1p was also found to interact with Mkk1p and Mkk2p, and the interaction required only the predicted C-terminal catalytic domain of Mkk1p. Furthermore, we detected protein-protein interactions between two Bck1p molecules via their N-terminal regions. Finally, Mkk2p and Mpk1p also interacted in the two-hybrid assay. These results suggest that the members of the PKC1-mediated MAP kinase cascade form a complex in vivo and that Pkc1p is capable of directly interacting with at least one component of this pathway.
Mol Gen Genet 1996 Jul 26
PMID:Protein-protein interactions in the yeast PKC1 pathway: Pkc1p interacts with a component of the MAP kinase cascade. 875 99

Experiments were carried out at different times of hibernation to ascertain whether prostaglandin is produced by Rana ovarian follicles during gonadotropin- or 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced in vitro ovulation. Ovarian fragments were cultured in amphibian Ringer in the presence or absence of frog pituitary homogenate (FPH, 0.05 gland/ml) or TPA (1 or 10 microM). After various periods of culture, incidence of ovulation was determined and prostaglandin F2 alpha (PGF2 alpha) accumulated in culture medium was measured by radioimmunoassay. FPH and TPA increased PGF2 alpha levels in medium in a dose-dependent manner. The time course of PGF2 alpha secretion and ovulation by FPH or TPA treatment varied during the hibernation period. In early-hibernation, FPH stimulated neither PGF2 alpha secretion nor ovulation while TPA stimulated PGF2 alpha secretion, although it failed to induce ovulation. In mid-hibernation, FPH and TPA effectively stimulated PGF2 alpha secretion and ovulation, but both events took place several hours later than those observed in late-hibernation. Some fragments obtained in mid-hibernation and most obtained in late-hibernation spontaneously produced PGF2 alpha in vitro without FPH or TPA treatment and in some instances spontaneously ovulated. Furthermore, FPH or TPA increased PGF2 alpha levels further or accelerated the time course of secretion by such fragments. In late-hibernation, PGF2 alpha secretion induced with FPH or TPA increased simultaneously with or later than onset of ovulation. Exogenous cAMP (2.5 mM) or 1-(5-isoquinolinylsulfonyl)-2-methylpiperazine (H-7, 100 microM), a PKC inactivator, markedly suppressed FPH- or TPA-stimulated PGF2 alpha secretion and ovulation in mid-hibernation. Indomethacin (IM, 5 micrograms/ml) strongly suppressed TPA- or FPH-stimulated PGF2 alpha production by fragments but its effect on ovulation varied among animals and at different times. IM suppressed ovulation of some ovarian fragments obtained in mid-hibernation, but failed to suppress hormone-induced ovulation in late-hibernation. Cycloheximide (5 micrograms/ml) and actinomycin D (1 microgram/ml) effectively suppressed FPH-stimulated PGF2 alpha production and ovulation, whereas actinomycin D reduced but failed to significantly suppress TPA-induced PGF2 alpha production in mid-hibernation. In general, effects of ovulation inhibitors exhibited strong seasonal variations and were less efficient as the breeding season approached. Taken together, the data suggest that elevated levels of PGF2 alpha are associated with spontaneous and hormone-induced ovulation, and PKC mediates gonadotropin induction of PGF2 alpha but not steroid synthesis in Rana ovaries.
Gen Comp Endocrinol 1995 Dec
PMID:Prostaglandin production and ovulation during exposure of amphibian ovarian follicles to gonadotropin or phorbol ester in vitro. 877 52


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