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)

We recently reported that a red meat (beef) diet relative to a casein-based diet increases protein kinase C (PKC) activity in rat colonic mucosa. The purpose of this study was to further elucidate the effects of a high-beef diet on colonic intracellular signal transduction by analyzing steady-state protein levels of different PKC isozymes as well as activities of the three types of sphingomyelinases. Male Wistar rats (n = 12/group) were fed AIN93G-based diets either high in beef or casein for 4 weeks. Rats fed the beef diet had significantly (P < 0.05) higher cytosolic PKC alpha and lower membrane PKC delta protein levels than rats fed the casein diet. The beef-fed rats also had alterations in subfractions of PKC zeta/lambda so that they had a significantly (P = 0.001) lower level of membrane 70 & 75 kDa fraction and a higher (P = 0.001) level of cytosolic 40 & 43 kDa fraction than rats fed the casein diet. Because protein levels analyzed with a PKC zeta-specific antibody were similar, these differences in PKC zeta/lambda were probably due to changes in PKC lambda expression. PKC beta2 levels did not differ between the dietary groups. Diet had no significant effect on the activity of acid, neutral, or alkaline sphingomyelinase. This study demonstrated that consumption of a high-beef diet is capable of modulating PKC isozyme levels in rat colon, which might be one of the mechanisms whereby red meat affects colon carcinogenesis.
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PMID:A high-beef diet alters protein kinase C isozyme expression in rat colonic mucosa. 1112 Apr 44

Feeding of protein deficient diet is known to alter the transmembrane signalling in brain of rat by reducing total protein kinase C (PKC) activity. Phospholipid metabolism regulates the activation of PKC through generation of second messengers and the extent of PKC activation accordingly influences the magnitude of phosphorylation of its endogenous substrate proteins. Thus it was speculated that ingestion of protein deficient diet may modify the turnover rate of membrane phospholipids and magnitude of phosphorylation of endogenous substrate proteins of PKC. The experiments were conducted on rats fed on three different types of laboratory prepared diets viz. casein (20% casein), deficient (4% protein, rice flour as source of protein) and supplemented (deficient diet supplemented with L-lysine and DL-threonine) for 28 days. The metabolism of phosphoinositides (PIs) and phosphatidyl choline (PC) was studied by equilibrium labeling with [3H] myo inositol and [14C methyl] choline chloride respectively. The phosphorylation of endogenous substrate proteins of PKC was studied by using 32P-gamma-ATP followed by SDS-PAGE and autoradiography. The results suggest that in deficient group, there is an increased incorporation of [3H] myo inositol in PIs and inositol phosphate pool in comparison to the casein group. The phosphatidyl inositol (PI) turnover reduced, although there was a marginal increase in the phosphatidyl inositol monophosphate (PIP) and phosphatidyl inositol bis phosphate (PIP2). Supplementation of diet showed a reversal of the pattern towards control to a considerable extent. In the deficient group, PC metabolism showed an increased incorporation of [14C methyl] choline in choline phospholipids but decreased incorporation in phosphoryl choline in comparison with the casein group. The increase in total PC contents was significant but marginal in residue contents. The turnover rate of PC increased only marginally and that of residue declined. Supplementation of diet reduced the total contents of PC and residue, but the turnover rate of PC and residue remained still higher. Phosphorylation of endogenous proteins showed four different proteins of 78, 46, 33 and 16 kDa to be the substrates of PKC in casein group. In deficient group, phosphorylation of these proteins increased markedly while supplementation of diet had a reversing effect rendering the values to be intermediate between casein and the supplemented group. The changes in phospholipid metabolism and in phosphorylation of endogenous substrate proteins of PKC suggest that dietary protein deficiency causes alterations in transmembrane signalling mechanism in rat brain. These effects are partially reversed by improving the quality of proteins in the diet.
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PMID:Effect of feeding protein deficient diet on phospholipid turnover and protein kinase C mediated protein phosphorylation in rat brain. 1121 7

Earlier data indicate that Lactobacillus rhomnosus GG ATCC 53103 (L. GG), a commensal intestinal bacterial strain, promotes the degradation of proteins in the gut in vivo, and bovine casein hydrolysed with L. GG-derived proteases suppresses lymphocyte proliferation in vitro. The present study aimed to evaluate the effect of L. GG-degraded bovine casein on T-cell activation, i.e. IL-2 mRNA expression and protein kinase C (PKC) translocation. To this end, Northern blot analyses for IL-2 mRNA expression and PKC assays with and without L. GG-degraded casein were carried out on T cells isolated from 11 healthy adults. Cell cultures in 8-11 experiments contained 1 mg ml(-1) bovine casein in degraded or undegraded form in the presence of a mitogen, i.e. phorbol 12,13-dibutyrate plus calcium ionophore (PBDu + A23187) or anti-CD3. Also IL-2, IL-4 and IFN-gamma syntheses were determined in 24-h culture supernatants. IL-2 mRNA expression was reduced in experiments with L. GG-degraded casein. In parallel, the IL-2 concentration in PBDu + A23187-stimulated culture supernatants, expressed as geometric means (95% confidence interval), decreased from 15,892 (7174-35,203) pg ml(-1) to 4744 (2095-10,742) pg ml(-1) when containing L. GG-degraded casein. L. GG-degraded casein inhibited PKC translocation, the action resembling that of PKC inhibitor, RO31-8220. These results extend previous data on L. GG-degraded casein, showing in vitro the suppression of T-cell activation.
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PMID:Suppression of T-cell activation by Lactobacillus rhamnosus GG-degraded bovine casein. 1136 Sep 22

Almost all the Ca(2+)-dependent protein kinase activity in nuclei purified from etiolated pea (Pisum sativum, L.) plumules is present in a single enzyme that can be extracted from chromatin by 0.3 molar NaCl. This protein kinase can be further purified 80,000-fold by salt fractionation and high performance liquid chromatography, after which it has a high specific activity of about 100 picomoles per minute per microgram in the presence of Ca2+ and reaches half-maximal activation at about 3 x 10(-7) molar free Ca2+, without calmodulin. It is a monomer with a molecular weight near 90,000. It can efficiently use histone III-S, ribosomal S6 protein, and casein as artificial substrates, but it phosphorylates phosvitin only weakly. Its Ca(2+)-dependent kinase activity is half-maximally inhibited by 0.1 millimolar chlorpromazine, by 35 nanomolar K-252a and by 7 nanomolar staurosporine. It is insensitive to sphingosine, an inhibitor of protein kinase C, and to basic polypeptides that block other Ca(2+)-dependent protein kinases. It is not stimulated by exogenous phospholipids or fatty acids. In intact isolated pea nuclei it preferentially phosphorylates several chromatin-associated proteins, with the most phosphorylated protein band being near the same molecular weight (43,000) as a nuclear protein substrate whose phosphorylation has been reported to be stimulated by phytochrome in a calcium-dependent fashion.
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PMID:Partial purification and characterization of a Ca(2+)-dependent protein kinase from pea nuclei. 1153 5

Effects of the dietary addition of orotic acid to a diet containing casein as a sole protein source on lipid levels in the liver and serum, activities of antioxidant enzymes in the liver, and some enzyme activities in serum, were compared with other diets containing egg protein, soy protein, or wheat gluten, respectively. 1. The contents in the liver of each lipid were increased by the addition of orotic acid as compared with those values without it. The orotic acid added to the casein diet caused accumulation of more liver total lipids, triacylglycerol, 1,2-diacylglycerol, and phospholipids than those fed three other diets. 2. The addition of orotic acid to the casein, but not to the other three diets, lowered the activities of liver superoxide dismutase and increased the activities of both serum ornithine carbamoyltransferase and alanine aminotransferase. Thus, the significant increase in serum ornithine carbamoyltransferase activities as the marker of liver lesions may result from the marked accumulation of liver lipids, decreased activities of hepatic superoxide dismutase, and the increased level of hepatic 1,2-diacylglycerol, followed by possibly the increased level of superoxide anion and increased activity of protein kinase C in rats fed the casein diet with orotic acid added.
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PMID:Orotic acid added to casein, but not to egg protein, soy protein, or wheat gluten diets increases 1,2-diacylglycerol levels and lowers superoxide dismutase activities in rat liver. 1175 5

Mitogenic cell proliferation requires a rapid and transient H2O2 generation, which is blocked by catalase or PKA activators. Previously, we observed that anemic HIV(+) individuals expressed acidic pIs of catalase in RBC with significantly high activities [Mol Cell Biochem 165: 77-81, 1996]. These findings led us to hypothesize that cell signaling molecules regulate catalase to control cell mitogenesis. To test the hypothesis, we determined (i) whether RBC counts correlate with their catalase activities, (ii) whether protein kinases and phosphatases alter catalase activity in vitro, and (iii) whether protein kinase activators increase catalase activity to suppress proliferation of cultured cells. The results indicated that RBC counts inversely correlated with RBC catalase activities in both HIV(+) (r: -0.6769, r2: 0.4582, n: 69 male, p < 0.0001) and HIV(-) (r: -0.3827, r2: 0.1464, n: 177 male, p < 0.0001) populations. Catalytic PKA, PKC and Casein Kinase II, but none of PKG, Ca2+/calmodulin kinase II and p34cdc/cyclinB, rapidly elevated catalase activity in vitro by up to 2-fold. Whereas a major CAT subunit (60 kDa) showed immunoreactive phosphoserine and phosphothreonine, the kinases- and gamma-32P-ATP-dependent phosphorylation occurred with a minor component (110 kDa). Among PKC isozymes examined, PKCzeta was the most effective modulator followed by PKCgamma, and protein phosphatase 1gamma and 2A decreased the catalase activity. PKA and PKCzeta activators of forskolin and okadaic acid increased catalase activity and 110 kDa expression in NIH3T3 cells up to 2.4-fold and suppressed the cell growth, showing an inverse correlation of the indices (r: -0.9286, r2: 0.8622, n: 18, p < 0.0001). Taken together, these results suggest for the first time that catalase is under the regulation of cell signaling molecules and capable of modulating mitogenic cell proliferation.
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PMID:Regulation of catalase enzyme activity by cell signaling molecules. 1248 79

A phosphorylated protein with a molecular mass of 25 000 (pp25) previously purified from the cytosolic fraction of Xenopus laevis oocytes is an effective phosphate acceptor for casein kinases and protein kinase C. In this study, based on the partial amino acid sequence of pp25, a cDNA was isolated that encodes a new yolk precursor protein, Xenopus vitellogenin B1, which contained the sequence encoding pp25. Both mRNA and protein of vitellogenin B1 were expressed in all of the female organs examined. In agreement with a previous report, the amount of vitellogenin B1 protein in the liver increased after stimulation with estrogen. These results suggest that pp25 is a cytosolic non-crystallized yolk protein nutrient source, but it might also play a role in rapid development.
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PMID:Mr 25 000 protein, a substrate for protein serine/threonine kinases, is identified as a part of Xenopus laevis vitellogenin B1. 1282 89

The following areas are discussed in this review: atherogenesis; cerebrovascular factors; hypoperfusion; beta-amyloid production; beta-amyloid fibril formation; beta-sheets; metal cations; reactive oxygen species/free radicals; chronic inflammatory factors; endogenous plasma heparin; lipoprotein lipase; polyamines; protein kinase C; casein kinases; phospholipase A2; serine proteases; myeloperoxidase; cyclooxygenase 2; cysteine proteases; caspases; proprotein convertases; aspartic proteases; cyclin proteinases; thrombin; tau hyperphosphorylation; advanced glycosylation end products; activator protein 1; calcium; apolipoprotein E epsilon4; histamine; blood-brain barrier; glutamate; transglutaminase; insulin-like growth factor 1.
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PMID:Pathogenic factors in vascular dementia and Alzheimer's disease. Multiple actions of heparin that probably are beneficial. 1528 60

Heterologous classical protein kinase C (cPKC) rat polyclonal antibodies showed presence of PKC homolog in Brassica juncea seedlings. It was purified to homogeneity by ammonium sulfate precipitation, diethyl amino ethyl (DEAE)-Sephacel, gel-filtration chromatography, and preparative gel electrophoresis. PKC-like kinase activity was fractionated into three distinct peaks after DEAE-Sephacel chromatography. The kinase activity was associated with a 55 kDa polypeptide. It was calcium dependent and lipids (phosphatidylserine, PS and oleyl acetylglycerol, OAG) stimulated it further, suggesting it to be a classical type protein kinase C. This was further confirmed by the stimulation of the kinase activity by phorbol 12-myristate 13-acetate (PMA) (a diacylglycerol, DAG analog) and its inhibition by H-7 (a general kinase inhibitor) and staurosporine (a PKC specific inhibitor). Histone was the preferred substrate over casein and BSA. Phosphoamino acid analysis showed it to be a serine/threonine kinase. Western blotting with the purified polypeptide showed an immunopositive 55 kDa polypeptide. In search of the substrate for the kinase in vitro phosphorylation was done in presence of kinase inhibitors. PKC-dependent phosphorylation was observed which was inhibited by PKC inhibitors (H-7 and staurosporine) and enhanced by PKC activator (PMA). Low temperature induced dephosphorylation of the same polypeptide. Direct involvement of PKC-dependent phosphorylation in early LT signaling is indicated for the first time.
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PMID:Purification and characterization of a PMA-stimulated kinase and identification of PMA-induced phosphorylation of a polypeptide that is dephosphorylated by low temperature in Brassica juncea. 1532 46

Mutations in the PARKIN gene are the most common cause of hereditary parkinsonism. The parkin protein comprises an N-terminal ubiquitin-like domain, a linker region containing caspase cleavage sites, a unique domain in the central portion, and a special zinc finger configuration termed RING-IBR-RING. Parkin has E3 ubiquitin-protein ligase activity and is believed to mediate proteasomal degradation of aggregation-prone proteins. Whereas the effects of mutations on the structure and function of parkin have been intensely studied, post-translational modifications of parkin and the regulation of its enzymatic activity are poorly understood. Here we report that parkin is phosphorylated both in human embryonic kidney HEK293 cells and human neuroblastoma SH-SY5Y cells. The turnover of parkin phosphorylation was rapid, because inhibition of phosphatases with okadaic acid was necessary to stabilize phosphoparkin. Phosphoamino acid analysis revealed that phosphorylation occurred mainly on serine residues under these conditions. At least five phosphorylation sites were identified, including Ser101, Ser131, and Ser136 (located in the linker region) as well as Ser296 and Ser378 (located in the RING-IBR-RING motif). Casein kinase-1, protein kinase A, and protein kinase C phosphorylated parkin in vitro, and inhibition of casein kinase-1 caused a dramatic reduction of parkin phosphorylation in cell lysates. Induction of protein folding stress in cells reduced parkin phosphorylation, and unphosphorylated parkin had slightly but significantly elevated autoubiquitination activity. Thus, complex regulation of the phosphorylation state of parkin may contribute to the unfolded protein response in stressed cells.
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PMID:Parkin phosphorylation and modulation of its E3 ubiquitin ligase activity. 1555 40


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