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)

Total PKC activity in BAEC incubated for 24 hrs in either 10% serum (FBS) or serum-deprived media (SDM) was similar. However, most of the activity (69%) in the FBS group was detected in the particulate fraction, while it was mainly in the cytosolic fraction (66%) in the SDM group. By confocal microscopy, there was diffuse cytoplasmic localization of the antibodies to the alpha and beta PKC isoforms. gamma PKC was not detected. Treatment of FBS or SDM cells with a phorbol ester resulted in an increase in PKC activity with translocation to the particulate fraction. PKC alpha immunofluorescence redistributed to the perinuclear region whereas PKC beta staining remained mostly cytosolic. Calphostin C, a PKC inhibitor, prevented the phorbol ester-induced increase in PKC activity and translocation.
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PMID:Immunocytochemical expression and localization of protein kinase C in bovine aortic endothelial cells. 144 92

We have studied the c-myc gene as a possible target of HBV X protein in liver carcinogenesis. Our results indicate that trans-activation by X protein occurs via PKC/AP1 signal transduction, suggesting a possible two-step mechanism in HBV related liver carcinogenesis.
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PMID:Trans-activation by hepatitis B virus X protein is mediated via a tumour promoter pathway. 145 Jul 27

Studies reported here determined the effect of dietary fat level on membrane phospholipid composition, phosphoinositide labeling, 1,2-sn-diacylglycerol and protein kinase C activity in epidermal cells from female Sencar mice. Animals were fed either high fat (24.6 g/100 g diet) or control (5 g/100 g diet) diets at constant energy intake for 6 to 7 wk or 15 to 22 wk, and epidermal cells were isolated. The level of phosphatidylinositol was significantly lower in the animals fed the control diet than in the animals fed the high fat diet (0.6 vs. 1.2 nmol/10(6) cells). The fatty acid composition of the phospholipids showed significantly lower arachidonic acid level in phosphatidylinositol when the animals were fed the high fat diet. Protein kinase C activity in the solubilized particulate and soluble fraction of the cells was 131 +/- 18% and 62 +/- 14% greater, respectively, in animals fed the high fat diet compared with animals fed control diet. The level of 1,2-sn-diacylglycerol was significantly higher in animals fed the high fat diet (mean nmol/mg lipid +/- SEM: control, 4.5 +/- 0.5; high fat, 7.0 +/- 0.5). Incorporation of [3H]inositol into inositol lipid was not altered by diet. Because protein kinase C and 1,2-sn-diacylglycerol have been implicated in tumor promotion, the increase in protein kinase C activity and the elevation of 1,2-sn-diacylglycerol in cells from animals fed the high fat diet may be important in the high cancer rate observed with these diets.
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PMID:Protein kinase C is activated and diacylglycerol is elevated in epidermal cells from Sencar mice fed high fat diets. 145 16

The action of protein kinase C on the stimulation of adenylate cyclase activity by the histamine H2 receptor was investigated in rat parietal cells. Protein kinase C was activated by preincubating cells with 12-O-tetradecanoylphorbol 13-acetate (TPA), and adenylate cyclase activity was measured in sonicated extracts. TPA (100 nM) inhibited adenylate cyclase activity stimulated by histamine (100 nM-500 microM). This effect was related to the concentration of TPA. TPA (100 nM) enhanced the stimulation of adenylate cyclase activity by forskolin (100 microM) but had no effect on the stimulation by NaF (10 mM). In conclusion, protein kinase C inhibits stimulation of adenylate cyclase by the histamine H2 receptor. This action could be mediated by changes in the number of affinity of histamine H2 receptors or in the coupling of the receptor to the stimulatory guanine nucleotide regulatory subunit Gs.
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PMID:Protein kinase C inhibits stimulation of adenylate cyclase by the histamine H2 receptor in rat parietal cells. 145 78

Calcium and phospholipid-dependent protein kinase (PKC) activity was detected mainly in the cytosol of the mouse sperm. The PKC in the cytosol fraction was partially purified by ion-exchange chromatography. Using the partially purified PKC, the phosphorylation of PKC substrates was examined in vitro. The phosphorylation of the 80 kDa protein was enhanced by phorbol ester treatment in vitro as well as in vivo. The partial amino acid sequence of this protein was homologous with that of guanosine 5'-cyclic monophosphate (cGMP)-dependent protein kinase and myosin light chain kinase, both of which are related to ligand-receptor-transduction. The present data suggest that the activation of PKC and subsequent specific protein phosphorylation might be involved in the regulation of the zona pellucida-induced acrosome reaction.
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PMID:80 kDa mouse sperm protein as a substrate of protein kinase C. 146 8

Diabetic retinopathy is one of the leading causes of vision loss in industrialized countries. Despite recent advances, the biochemical basis for the development of this diabetic complication is uncertain. Although retinal circulation is unique in that it is readily observable noninvasively, retinal tissue is extremely difficult to study in humans because of the problems inherent in obtaining fresh, appropriate biopsy material. Moreover, because of the difficulties in working with animal models of diabetic retinopathy, such as the dog, many investigators have turned to cell-culture models, especially those using primary cultures of retinal capillary endothelial cells and pericytes. Diabetic retinopathy involves both morphological and functional changes in the retinal capillaries. Morphological changes include basement membrane thickening and pericyte disappearance; functional changes include one important early change--increased permeability--which may be attributable to endothelial cell changes and basement membrane leakiness. Investigators have described major biochemical changes in cellular signaling pathways, including myo-inositol, inositol phosphates, and DAG metabolism, as well as decreased Na(+)-K(+)-ATPase and increased PKC activity. These defects may be related to the way endothelial cells and pericytes synthesize and interact with the extracellular matrix. Abnormalities in endothelial cell or pericyte interaction with the basement membrane may in turn lead to functional abnormalities, such as increased permeability.
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PMID:Current hypotheses for the biochemical basis of diabetic retinopathy. 146 44

Annexin II tetramer (A-IIt) is a member of the annexin family of Ca2+ and phospholipid-binding proteins. The ability of this protein to aggregate both phospholipid vesicles and chromaffin granules has suggested a role for the protein in membrane trafficking events such as exocytosis. A-IIt is also a major intracellular substrate of both pp60src and protein kinase C; however, the effect of phosphorylation on the activity of this protein is unknown. In the current report we have examined the effect of phosphorylation on the lipid vesicle aggregation activity of the protein. Protein kinase C catalyzed the incorporation of 2.1 +/- 0.8 mol of phosphate/mol of A-IIt. Phosphorylation of A-IIt caused a dramatic decrease in the rate and extent of lipid vesicle aggregation without significantly effecting Ca(2+)-dependent lipid binding by the phosphorylated protein. Phosphorylation of A-IIt increased the A50%(Ca2+) of lipid vesicle aggregation from 0.18 microM to 0.65 mM. Activation of A-IIt phosphorylation, concomitant with activation of lipid vesicle aggregation, inhibited both the rate and extent of lipid vesicle aggregation but did not cause disassembly of the aggregated lipid vesicles. These results suggest that protein kinase C-dependent phosphorylation of A-IIt blocks the ability of the protein to aggregate phospholipid vesicles without affecting the lipid vesicle binding properties of the protein.
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PMID:Phosphorylation of annexin II tetramer by protein kinase C inhibits aggregation of lipid vesicles by the protein. 146 10

In the present study, we examined changes in immunoreactivity (ir) for the gamma-isoform of protein kinase C (PKC gamma) in mouse hippocampus in relation to spatial memory processes employing the monoclonal antibody 36G9 raised against purified PKC gamma. Learning and memory were assessed by performance in a free-choice spatial pattern paradigm in a hole board in which the animals learned the pattern of 4 baited holes out of 16 holes. Adult male house mice were used, divided in four groups. Three control groups were formed: group N, naive (blank controls); group H, habituated (animals were for 5 consecutive days introduced to the hole board with all holes baited); and group PT, pseudotrained (animals were for 13 consecutive days introduced to the hole board with all holes baited). The T (trained) group was for 5 consecutive days introduced to the hole board with all holes baited (similar to the H and PT groups) followed by 8 successive days with only four holes baited in a fixed pattern. Behaviorally, following the first 5 d, the PT group crossed the hole board randomly, whereas the T group gradually learned to orientate in the hole board. The mice were killed 24 hr after the last performance. A shift in 36G9-ir appeared from the cell somata to the dendrites of hippocampal principal neurons when comparing the H and PT group, respectively. In contrast, the T group showed strong PKC gamma-ir in both cell somata and dendrites, which clearly exceeded that of the H and PT mice. In this way, 36G9-ir reveals the physiologically activated neurons involved in hole board learning.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Changes in PKC gamma immunoreactivity in mouse hippocampus induced by spatial discrimination learning. 146 69

1. Sodium absorption is the dominant ion transport process in conducting airways and is a major factor regulating the composition of airway surface liquid. However, little is known about the control of airway sodium transport by intracellular regulatory pathways. 2. In sheep tracheae and human bronchi mounted in Ussing chambers under short circuit conditions, the sodium current can be isolated by pretreating tissues with acetazolamide (100 microM) to inhibit bicarbonate secretion, bumetanide (100 microM) to inhibit chloride secretion and phloridzin (200 microM) to inhibit sodium-glucose cotransport. This sodium current consists of amiloride-sensitive (57%) and amiloride-insensitive (43%) components. 3. The regulation of the isolated sodium current by three second messenger pathways was studied using the calcium ionophore A23187 to elevate intracellular calcium, a combination of forskolin and the phosphodiesterase inhibitor zardaverine to elevate intracellular cyclic AMP, and the phorbol ester 12,13-phorbol dibutyrate (PDB) to stimulate protein kinase C. 4. In sheep trachea, A23187 produces a dose-related inhibition of the sodium current with maximal effect (38% of ISC) at 10 microM and IC50 1 microM. This response affects both the amiloride-sensitive and insensitive components of the sodium current and is not altered by prior stimulation of protein kinase C or elevation of intracellular cyclic AMP. In human bronchi, A23187 (10 microM) produced a significantly greater inhibition of ISC (68%), a response which was unaffected by prior treatment with PDB or forskolin-zardaverine. 5. In sheep trachea, stimulation of protein kinase C with PDB produced a dose-related inhibition of ISC maximal (56% of ISC) at 50 nM (IC50 7 nM). This response was abolished by amiloride (100 microM) pretreatment suggesting a selective effect on the amiloride-sensitive component of the sodium current. The response was not altered by prior elevation of intracellular calcium or cyclic AMP. PDB (10 nM) caused a similar inhibition of ISC in human bronchi (43%). The effect of PKC stimulation following pretreatment with A23187 was diminished in human bronchi. Elevating intracellular cyclic AMP did not alter this response. 6. Addition of forskolin (1 microM) together with the phosphodiesterase inhibitor zardaverine (100 microM) produced a mean 35-fold increase in intracellular cyclic AMP in sheep trachea. This was associated with a small, but significant, 6% transient increase in ISC followed by a significant 4% fall. Neither effect could be abolished by amiloride pretreatment. In human bronchi, a small decrease in ISC which could not be distinguished from that occurring in controls was observed.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Second-messenger regulation of sodium transport in mammalian airway epithelia. 146 41

1. The effect of a sunflower oil-enriched diet on plasma membrane-bound protein kinase C, protein kinase A, casein and tyrosine kinase activities was studied. 2. The diet induced an increase in the content of linoleic acid and a decrease in the content of palmitic acid. The anisotropy parameter (rs) of the fluorescence probe DPH and SDPH decreased strongly in the experimental group. 3. Protein kinase C was stimulated more than two times. Tyrosine kinase, protein kinase A and casein kinase activities were increased by 65, 57 and 40%, respectively. 4. We suggest that a more fluid lipid environment favours higher plasma membrane-bound protein kinase activities.
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PMID:Effect of a sunflower oil-supplemented diet on protein kinase activities of rat liver plasma membranes. 147 8


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