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)

cDNA clones coding for novel protein kinase C delta (nPKC delta) were isolated from a mouse brain cDNA library. Mouse nPKC delta consists of 674 amino acid residues and has sequence identity of 95% with rat nPKC delta. Antiserum raised against a C-terminal peptide of rat nPKC delta identified a 79-kDa protein in COS cells transfected with a mouse nPKC delta cDNA expression plasmid. nPKC delta expressed in COS1 cells had phorbol-ester-binding activity and protein kinase activity in a phorbol-ester- or diacylglycerol-dependent manner, like conventional protein kinase C (cPKC) isozymes and nPKC epsilon. However, nPKC delta, like nPKC epsilon, is not activated by Ca2+, a known activator of cPKCs, and requires lower concentrations of Mg2+ for full activation than cPKCs. Moreover, apparent kinetic constants for synthetic oligopeptides (MBP4-14, EGFR peptide and epsilon-peptide) were quite different between nPKC delta and cPKC in two different conditions. Among various phospholipids tested, phosphatidylinositol is the most potent activator of nPKC delta, in clear contrast to cPKCs and nPKC epsilon. Limited proteolysis of nPKC delta generated a C-terminal active fragment with a cofactor-independent kinase activity. Northern blot analysis indicated that nPKC delta, like cPKC alpha, is widely distributed in almost all the tissues and cells examined and, in some cases such as fibroblast cells, exists as a major PKC type. These results suggest that nPKC delta is involved in fundamental cellular functions regulated by diacylglycerols and mimicked by phorbol esters.
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PMID:Structure and properties of a ubiquitously expressed protein kinase C, nPKC delta. 176 3

Isolated interphase lamin C, obtained from Ehrlich ascites tumor cells, was digested by Lys-C endoproteinase, the resulting peptides separated by reversed-phase HPLC and subjected to microsequencing in order to identify phosphorylation sites in interphase and following phosphorylation in vitro by cdc2-kinase, protein kinase C (PKC) and protein kinase A (PKA), respectively. Nuclear lamin C showed partial phosphorylation of Ser392 and Ser409, and possibly Ser407 in interphase. Phosphorylation was increased in response to cdc2-kinase at Ser390 and Ser392 and to PKC at Ser572. The N-terminal peptide (aa 1-32) containing consensus sequences for the 3 kinases was phosphorylated by cdc2-kinase, PKC and PKA. The sequence data suggests that multiple molecular switches via lamina modification control the dynamic behaviour of the nucleoskeleton during the cell cycle.
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PMID:Identification of phosphorylation sites on murine nuclear lamin C by RP-HPLC and microsequencing. 195 8

The domain structure of duck gizzard caldesmon was investigated. A single thiol group is located in the vicinity of the C-terminus of the protein. A simple method for the purification of a short (21 kDa) C-terminal peptide formed after chemical cleavage of caldesmon at cysteine residues was evolved. The C-terminal peptide of caldesmon interacts with calmodulin with an affinity one order of magnitude higher than that of native caldesmon. The Ca2+/phospholipid-dependent protein kinase (protein kinase C) transfers about 2 mol of phosphate per mol of caldesmon. All sites phosphorylated by protein kinase C are located in the short (21 kDa) C-terminal peptide of caldesmon. Phosphorylation does not affect the interaction of caldesmon with calmodulin.
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PMID:Some properties of duck gizzard caldesmon. 198 78

Muscarinic acetylcholine receptors purified from porcine cerebra or atria were covalently labeled with [3H]propylbenzilylcholine mustard ([3H]PrBCM), and then the labeled receptors were subjected to limited hydrolysis with trypsin, V8 protease, and lysyl endopeptidase, followed by analysis involving sodium dodecyl sulfate-polyacrylamide gel electrophoresis, fluorography, autoradiography, or immunostaining. The labeled peptides were located on the basis of their reactivity with antibodies raised against three synthetic peptides with partial sequences of the m1 or m2 receptor, and of their sensitivity to endoglycosidase F, which was taken as evidence that they contain glycosylation sites near the N terminus. The [3H]PrBCM-binding site in both cerebral and atrial receptors was found to be located between the N terminus and the second intracellular loop, because the size of the smallest deglycosylated peptide that contained both the [3H]PrBCM-binding and glycosylation sites was approximately 16 kDa. Cerebral receptors were 32P-phosphorylated with protein kinase C, and the major phosphorylation sites in cerebral muscarinic receptors were found to be located in a C-terminal segment including a part of the third intracellular loop, because a 32P-labeled peptide of 12-14 kDa reacted with anti-(m1 C-terminal peptide) antiserum. The presence of an intramolecular disulfide bond, probably between Cys 98 and Cys 178 in the first and second extracellular loops, respectively, was suggested by the finding that a peptide of approximately 17 kDa containing the [3H]PrBCM-binding site, but not the glycosylation sites, was partly converted to a peptide of approximately 12 kDa on treatment with beta-mercaptoethanol.
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PMID:Location in muscarinic acetylcholine receptors of sites for [3H]propylbenzilylcholine mustard binding and for phosphorylation with protein kinase C. 233 46

The 18,000-dalton bovine lens fiber cell intrinsic membrane protein MP18 was phosphorylated on a serine residue by both cAMP-dependent protein kinase and protein kinase C. In addition, this protein bound calmodulin and was recognized by a monoclonal antibody (2D10). These different regions were localized using enzymatic and chemical fragmentation of electrophoretically purified MP18 that had been phosphorylated with either cAMP-dependent protein kinase or protein kinase C. Partial digestion of 32P-labeled MP18 with protease V8 resulted in a Mr = 17,000 peptide that bound calmodulin, but neither contained 32P or was recognized by the monoclonal antibody 2D10. Furthermore, the 17-kDa peptide had the same N-terminal amino acid sequence as MP18. Thus, the monoclonal antibody 2D10 recognition site and the protein kinase phosphorylation site(s) are close together and confined to a small region in the C terminus of MP18. This conclusion was confirmed in experiments where MP18 was fragmented with trypsin, endoproteinase Lys-C, or CNBr. The location of the phosphorylation site was confirmed by sequencing the small 32P-labeled, C-terminal peptide that resulted from protease V8 digestion of 32P-labeled MP18. This peptide contained a consensus sequence for cAMP-dependent protein kinase.
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PMID:Structural organization of the lens fiber cell plasma membrane protein MP18. 258 4

7B2 is a 23-kDa protein encoded by a single gene that is expressed in a variety of neuroendocrine tissues. Although its physiological role has not yet been elucidated, its presence in secretory granules suggests a function in the secretory machinery of certain neuronal and endocrine cells in various species. The present study characterizes the expression of 7B2 in endocrine pancreatic cells. We demonstrate that: (i) 7B2 is highly expressed in human insulinomas; (ii) its ultrastructural localization, associated with secretory granules of A and B cells of the islets, suggests a participation of 7B2 in the secretion of insulin and glucagon; (iii) sequences located in the first intron of the 7B2 gene are required for its transcription in either insulinoma or glucagonoma cell lines; and (iv) in a B cell-like insulinoma cell line, the transcription of 7B2 is regulated by protein kinase A and protein kinase C activators, while in an A-like insulinoma cell line, 7B2 gene transcription seems to be constitutively activated.
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PMID:Expression, intracellular localization, and gene transcription regulation of the secretory protein 7B2 in endocrine pancreatic cell lines and human insulinomas. 751 67

To determine whether the receptor-like protein-tyrosine phosphatase, RPTP alpha, which is widely expressed in both the developing and adult mouse, is regulated by phosphorylation, we raised antiserum against a C-terminal peptide. This antiserum precipitated a 140-kDa protein from metabolically 35S-labeled NIH3T3 cells. Using this antiserum, we showed that endogenous RPTP alpha is constitutively phosphorylated in NIH3T3 cells, predominantly on two serines, which we identified as Ser-180 and Ser-204, lying in the juxtamembrane domain. 12-O-tetradecanoylphorbol-13-acetate (TPA) stimulation of quiescent NIH3T3 cells rapidly increased phosphorylation of Ser-180 and Ser-204. Purified protein kinase C (PKC) phosphorylated bacterially expressed RPTP alpha at Ser-180 and Ser-204. When wild type and S180A/S204A double mutant RPTP alpha S were transiently expressed in 293 human embryonic kidney cells, TPA stimulated phosphorylation of wild type but not of double mutant RPTP alpha. PKC down-regulation following prolonged exposure to TPA diminished TPA-stimulated RPTP alpha phosphorylation. Taken together, these results indicate that RPTP alpha is a direct substrate for (PKC). Examination of 293 cells expressing exogenous RPTP alpha using immunofluorescence confocal microscopy showed that RPTP alpha exists predominantly in two subcellular compartments: in dense intracellular granules or dispersed within the plasma membrane. TPA treatment caused redistribution of some intracellular RPTP alpha to the cell surface, but this did not require direct phosphorylation of RPTP alpha at Ser-180/Ser-204. Our results suggest that activation of PKC by cytokines modulates RPTP alpha function in several different ways.
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PMID:The receptor-like protein-tyrosine phosphatase, RPTP alpha, is phosphorylated by protein kinase C on two serines close to the inner face of the plasma membrane. 753 34

Phosphorylation with endogenous protein kinase C causes the membrane skeletal protein, band 4.1, to lose its capacity to attach to one of two classes of high-affinity binding sites on the red cell membrane. These sites are the ones eliminated by proteolysis in situ of glycophorin C; the surviving type of site is located in a C-terminal peptide of the glycophorin C, retained on the membrane after proteolysis, which is also the site of attachment of p55. A synthetic peptide, comprising the 28 C-terminal residues of glycophorin C, also binds protein 4.1. Phosphorylation of the intact cells, stimulated by phorbol ester, approximately halves the retention of glycophorin C in the membrane cytoskeletons prepared from these cells and reduces the affinity of extracellular glycophorin C epitopes for their antibody.
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PMID:Interaction of protein 4.1 with the red cell membrane: effects of phosphorylation by protein kinase C. 775 24

Incubation of B chronic lymphocytic leukemia (B-CLL) cells with phorbol esters resulted in the phosphorylation of three Triton-soluble, heat-stable, acidic proteins with apparent M(r) of 80 KDa, 60 KDa and 43 KDa. The characteristics of the three proteins suggested that they could be related to the myristoylated, alanine-rich, C-kinase substrate (MARCKS). p80 was immunoprecipitated with an antibody against the N-terminal peptide of MARCKS. p43 co-migrated with mouse MRP/Mac-MARCKS (MARCKS-related protein). p60 is the most prominent substrate of protein kinase C in B-CLL cells.
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PMID:Phosphorylation of the MARCKS family of protein kinase C substrates in human B chronic lymphocytic leukemia cells. 776 46

GAP-43 isolated from calf brain was analyzed by the electrospray mass spectrometry. The mass spectrum of the intact protein showed two species with a mass difference of 80 Da, suggesting that the isolated GAP-43 contains phosphorylated species. To establish the in vivo phosphorylation sites, the protein was digested with trypsin, and analyzed by the liquid chromatography/mass spectrometry technique, in which a capillary reversed-phase chromatography column was connected on line to an electrospray mass spectrometer. Two pairs of peptides with a mass difference of 80 Da were observed. From the tandem mass spectrometry, two novel phosphorylation sites (Thr-87 and Ser-152) were identified. The novel phosphorylation sites contain proline immediately after the phosphorylated serines. No phosphorylated peptide was detected corresponding to the protein kinase C or casein kinase II phosphorylation sites. A peptide corresponding to the acetylated N-terminal peptide was also identified. The mass of the peptide suggests that the 2 cysteinyl residues are not palmitoylated but form a disulfide bridge.
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PMID:A mass spectrometric study on the in vivo posttranslational modification of GAP-43. 807 93


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