1
|
Schreiber KL, Paquet L, Allen BG, Rindt H. Protein kinase C isoform expression and activity in the mouse heart. Am J Physiol Heart Circ Physiol 2001; 281:H2062-71. [PMID: 11668067 DOI: 10.1152/ajpheart.2001.281.5.h2062] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The expression of protein kinase C (PKC) isoforms in the developing murine ventricle was studied using Western blotting, assays of PKC activity, and immunoprecipitations. The abundance of two Ca2+-dependent isoforms, PKCalpha and PKCbetaII, as well as two Ca2+-independent isoforms, PKCdelta and PKCepsilon, decreased during postnatal development to <15% of the levels detected at embryonic day 18. The analysis of the subcellular distribution of the four isoforms showed that PKCdelta and PKCepsilon were associated preferentially with the particulate fraction in fetal ventricles, indicating a high intrinsic activation state of these isoforms at this developmental time point. The expression of PKCalpha in cardiomyocytes underwent a developmental change. Although preferentially expressed in neonatal cardiomyocytes, this isoform was downregulated in adult cardiomyocytes. In fast-performance liquid chromatography-purified ventricular extracts, the majority of PKC activity was Ca2+-independent in both fetal and adult ventricles. Immunoprecipitation assays indicated that PKCdelta and PKCepsilon were responsible for the majority of the Ca2+-independent activity. These studies indicate a prominent role for Ca2+-independent PKC isoforms in the mouse heart.
Collapse
Affiliation(s)
- K L Schreiber
- Montreal Heart Institute, Research Center, Montreal, Quebec, Canada H1T 1C8
| | | | | | | |
Collapse
|
2
|
Beil W, Obst B, Wagner S, Sewing KF. The Helicobacter pylori fatty acid cis-9,10-methyleneoctadecanoic acid stimulates protein kinase C and increases DNA synthesis of gastric HM02 cells. Br J Cancer 1998; 77:1852-6. [PMID: 9667658 PMCID: PMC2150327 DOI: 10.1038/bjc.1998.308] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Protein kinase C (PKC) has been implicated in the control of epithelial proliferative activity and in the process of malignant transformation. Helicobacter pylori (H.p.) infection is associated with increased gastric epithelial cell proliferation and has been linked with gastric carcinoma. In the present study, we report that the H.p. fatty acid cis-9,10-methyleneoctadecanoic acid (MOA) directly activates PKC (Ka 3.3 microM). The effect of MOA upon PKC activation was Ca2+ dependent but did not require phosphatidylserine as phospholipid cofactor. MOA increased the stimulatory effect of phosphatidylserine at low Ca2+ (1 microM) concentrations. These findings indicate that MOA interacts at the phospholipid- and the diacylglycerol-binding domain to elicit PKC activation. Treatment of gastric mucous cells HM02 caused translocation of PKC from the cytosol to the nuclear, mitochondrial and membrane fraction. Furthermore, MOA stimulated [3H]thymidine incorporation into the DNA of HM02 cells. Our results show that the H.p. fatty acid MOA activates PKC and increases DNA synthesis in gastric epithelial cells.
Collapse
Affiliation(s)
- W Beil
- Department of General Pharmacology, Hannover Medical School, Germany
| | | | | | | |
Collapse
|
3
|
Chang BY, Conroy KB, Machleder EM, Cartwright CA. RACK1, a receptor for activated C kinase and a homolog of the beta subunit of G proteins, inhibits activity of src tyrosine kinases and growth of NIH 3T3 cells. Mol Cell Biol 1998; 18:3245-56. [PMID: 9584165 PMCID: PMC108906 DOI: 10.1128/mcb.18.6.3245] [Citation(s) in RCA: 215] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/1997] [Accepted: 03/02/1998] [Indexed: 02/06/2023] Open
Abstract
To isolate and characterize proteins that interact with the unique domain and SH3 and SH2 domains of Src and potentially regulate Src activity, we used the yeast two-hybrid assay to screen a human lung fibroblast cDNA library. We identified RACK1, a receptor for activated C kinase and a homolog of the beta subunit of G proteins, as a Src-binding protein. Using GST-Src fusion proteins, we determined that RACK1 binds to the SH2 domain of Src. Coimmunoprecipitation of Src and RACK1 was demonstrated with NIH 3T3 cells. Purified GST-RACK1 inhibited the in vitro kinase activity of Src in a concentration-dependent manner. GST-RACK1 (2 microM) inhibited the activities of purified Src and Lck tyrosine kinases by 40 to 50% but did not inhibit the activities of three serine/threonine kinases that we tested. Tyrosine phosphorylation on many cellular proteins decreased in 293T cells that transiently overexpressed RACK1. Src activity and cell growth rates decreased by 40 to 50% in NIH 3T3 cells that stably overexpressed RACK1. Flow cytometric analyses revealed that RACK1-overexpressing cells do not show an increased rate of necrosis or apoptosis but do spend significantly more time in G0/G1 than do wild-type cells. Prolongation of G0/G1 could account for the increased doubling time of RACK1-overexpressing cells. We suggest that RACK1 exerts its effect on the NIH 3T3 cell cycle in part by inhibiting Src activity.
Collapse
Affiliation(s)
- B Y Chang
- Department of Medicine, Stanford University, Stanford, California 94305, USA
| | | | | | | |
Collapse
|
4
|
Zhang ZH, Johnson JA, Chen L, El-Sherif N, Mochly-Rosen D, Boutjdir M. C2 region-derived peptides of beta-protein kinase C regulate cardiac Ca2+ channels. Circ Res 1997; 80:720-9. [PMID: 9130453 DOI: 10.1161/01.res.80.5.720] [Citation(s) in RCA: 78] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
We have previously shown that alpha1-adrenergic activation inhibited beta-adrenergic-stimulated L-type Ca2+ current (I(Ca)). To determine the role of protein kinase C (PKC) in this regulation, the inositol trisphosphate pathway was bypassed by direct activation of PKC with 4beta-phorbol 12-myristate 13-acetate (PMA). To minimize Ca2+-induced Ca2+ inactivation, Ba2+ current (I(Ba)) was recorded through Ca2+ channels in adult rat ventricular myocytes. We found that PMA (0.1 micromol/L) consistently inhibited basal I(Ba) by 40.5+/-7.4% and isoproterenol (ISO, 0.1 micromol/L)-stimulated I(Ba) by 48.9+/-7.8%. These inhibitory effects were not observed with the inactive phorbol ester analogue alpha-phorbol 12,13-didecanoate (0.1 micromol/L). To identify the PKC isozymes that mediate these PMA effects, we intracellularly applied peptide inhibitors of a subclass of PKC isozymes, the C2-containing cPKCs. These peptides (betaC2-2 and betaC2-4) specifically inhibit the translocation and function of C2-containing isozymes (alpha-PKC, betaI-PKC, and betaII-PKC), but not the C2-less isozymes (delta-PKC and epsilon-PKC). We first used the pseudosubstrate peptide (0.1 micromol/L in the pipette), which inhibits the catalytic activity of all the PKC isozymes, and found that PMA-induced inhibition of ISO-stimulated I(Ba) was reduced to 16.8+/-7.4% but was not affected by the scrambled pseudosubstrate peptide. The effects of PMA on basal and ISO-stimulated I(Ba) were then determined in the presence of C2-derived peptides or control peptides. When the pipette contained 0.1 micromol/L of betaC2-2 or betaC2-4, PMA-induced inhibition of basal I(Ba) was 26.1+/-4.5% and 23.6+/-2.2%, respectively. Similarly, ISO-stimulated I(Ba) was inhibited by 29.9+/-6.6% and 29.3+/-7.8% in the presence of betaC2-2 and betaC2-4, respectively. In contrast, there was no significant change in the effect of PMA in the presence of control peptides, scrambled betaC2-4, or pentalysine. Finally, PMA-induced inhibition of basal and ISO-stimulated I(Ba) was almost completely abolished in cells dialyzed with both betaC2-2 and betaC2-4. Together, these data suggest a role for C2-containing isozymes in mediating PMA-induced inhibition of L-type Ca2+ channel activity.
Collapse
Affiliation(s)
- Z H Zhang
- Department of Medicine, State University of New York, Health Science Center, and the Veterans Administration Medical Center, Brooklyn 11209, USA
| | | | | | | | | | | |
Collapse
|
5
|
Ventura C, Pintus G, Fiori MG, Bennardini F, Pinna G, Gaspa L. Opioid peptide gene expression in the primary hereditary cardiomyopathy of the Syrian hamster. I. Regulation of prodynorphin gene expression by nuclear protein kinase C. J Biol Chem 1997; 272:6685-92. [PMID: 9045700 DOI: 10.1074/jbc.272.10.6685] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Prodynorphin gene expression was investigated in adult ventricular myocytes isolated from normal (F1B) or cardiomyopathic (BIO 14.6) hamsters. Prodynorphin mRNA levels were higher in cardiomyopathic than in control myocytes and were stimulated by treatment of control cells with the protein kinase C (PKC) activator 1, 2-dioctanoyl-sn-glycerol. Both chelerythrine and calphostin C, two PKC inhibitors, abolished the stimulatory effect of the diglyceride and significantly reduced prodynorphin gene expression in cardiomyopathic myocytes. Nuclear run-off experiments indicated that the prodynorphin gene was regulated at the transcriptional level and that treatment of nuclei isolated from control cells with 1, 2-dioctanoyl-sn-glycerol increased prodynorphin gene transcription, whereas chelerythrine or calphostin C abolished this transcriptional effect. Direct exposure of nuclei isolated from cardiomyopathic myocytes to these inhibitors markedly down-regulated the rate of gene transcription. The expression of PKC-alpha, -delta, and -epsilon, as well as PKC activity, were increased in nuclei of cardiomyopathic myocytes compared with nuclei from control cells. The levels of both intracellular and secreted dynorphin B, a biologically active product of the gene, were higher in cardiomyopathic than in control cells and were stimulated or inhibited by cell treatment with 1,2-dioctanoyl-sn-glycerol or PKC inhibitors, respectively.
Collapse
Affiliation(s)
- C Ventura
- Institute of Biological Chemistry "A. Bonsignore," School of Medicine, University of Sassari, Viale San Pietro 43/B, 07100 Sassari, Italy
| | | | | | | | | | | |
Collapse
|
6
|
Wientzek M, Allen BG, McDonald-Jones G, Katz S. Characterization of calcium-dependent forms of protein kinase C in adult rat ventricular myocytes. Mol Cell Biochem 1997; 166:11-23. [PMID: 9046017 DOI: 10.1023/a:1006861011857] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The presence and subcellular localization of the Ca2+-dependent protein kinase C (PKC) isoforms alpha and beta were investigated in freshly isolated adult rat cardiac ventricular myocytes. PKC activity was measured in cytosolic and particulate fractions prepared from control myocytes and those treated with either phorbol ester (phorbol 12-myristate 13-acetate, PMA) or a permeant synthetic diacylglycerol analog (1-oleoyl-2-acetylglycerol, OAG) in the absence or presence of an inhibitor of diacylglycerol kinase activity, compound R59022. Preliminary studies detected no Ca2+-/phospholipid-dependent histone kinase activity in either subcellular fraction. To reproducibly observe Ca2+-/phospholipid-dependent protein kinase activity, partial purification using a MonoQ HR 5/5 column and the presence of the peptide inhibitor of the cAMP-dependent protein kinase were essential. MonoQ chromatography of cytosolic and particulate fractions resulted in three peaks of Ca2+/phospholipid-dependent protein kinase activity. In the cytosolic fraction a large peak of activity eluted at 230-300 mM NaCl. Isoform-specific antisera indicated both PKC alpha and PKC beta were present. In the particulate fraction two peaks of Ca2+-/phospholipid-dependent protein kinase activity, both containing PKCa immunoreactivity, were observed. The larger peak eluted at 230-300 mM NaCl. In addition, a peak eluting at lower salt concentrations contained a Ca2+-/phospholipid-independent histone kinase activity. This peak of kinase activity contained PKC alpha immunoreactive bands of 80- and 50-kDa. The 80-kDa band was the holoenzyme of PKC alpha whereas the band of lower molecular mass was likely a proteolytic fragment. In both cytosolic and particulate fractions, the peak of kinase activity eluting at 230-300 mM NaCl contained PKC alpha in the form of an 80-kDa doublet; this suggested the presence of autophosphorylated PKC. Incubation of the myocytes with PMA, but not OAG, resulted in translocation of PKC from the cytosolic to the particulate fraction. Curiously, a transient decrease in PKC activity was observed in both subcellular fractions following treatment with either OAG or ethanol (1%). Results from this study show that freshly isolated adult rat cardiac ventricular myocytes contain both PKC alpha and PKC beta, and that these isoforms translocate to the particulate fraction in response to treatment with PMA, but not OAG.
Collapse
Affiliation(s)
- M Wientzek
- Division of Pharmacology and Toxicology, Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, Canada
| | | | | | | |
Collapse
|
7
|
Eskildsen-Helmond YE, Gho BC, Bezstarosti K, Dekkers DH, Soei LK, Van Heugten HA, Verdouw PD, Lamers JM. Exploration of the possible roles of phospholipase D and protein kinase C in the mechanism of ischemic preconditioning in the myocardium. Ann N Y Acad Sci 1996; 793:210-25. [PMID: 8906167 DOI: 10.1111/j.1749-6632.1996.tb33516.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- Y E Eskildsen-Helmond
- Department of Biochemistry, Faculty of Medicine & Health Sciences, Erasmus University Rotterdam, The Netherlands
| | | | | | | | | | | | | | | |
Collapse
|
8
|
Allen BG, Katz S. Phosphorylation of cardiac junctional and free sarcoplasmic reticulum by PKC alpha, PKC beta, PKA and the Ca2+/calmodulin-dependent protein kinase. Mol Cell Biochem 1996; 155:91-103. [PMID: 8700163 DOI: 10.1007/bf00229306] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Phosphorylation of cardiac junctional and free sarcoplasmic reticulum (SR) by protein kinase C (PKC) isoforms alpha and beta was investigated. Both SR and PKC were isolated from canine heart. Junctional and free SR vesicles were prepared by calcium-phosphate-loading. The substrate specificities of PKC alpha and PKC beta were found to be similar in both SR fractions. A high molecular weight junctionally-associated protein was phosphorylated by PKA, PKC and an endogenous Ca2+/calmodulin-dependent protein kinase activity: the highest levels of phosphate incorporation being catalysed by the latter kinase. In addition to this high molecular weight junctionally-associated protein, PKC induced phosphorylation of 45, 96 kDa and several proteins of greater than 200 kDa in junctional SR. A protein of 96 kDa was phosphorylated by both isoforms in junctional and free SR. The major substrate for PKA, PKC alpha, PKC beta and the Ca2+/calmodulin-dependent protein kinase, in both junctional and free SR, was phospholamban. Although the phosphorylation of phospholamban by PKC was activated by Ca2+, a component of this activity appeared to be independent of Ca2+. PKC-mediated phosphorylation of phospholamban was fully activated by 1 microM Ca2+ whereas the Ca2+/calmodulin dependent kinase required concentrations in excess of 5 microM Ca2+. In the in vitro system employed in these studies, the concentrations of either PKC alpha or the catalytic subunit of PKA required to phosphorylate phospholamban were found to be similar. In addition, in the presence of a 15 kDa sarcolemmal-associated protein, which becomes phosphorylated upon activation of PKC in vivo, phosphorylation of phospholamban by PKC was unaffected. These results demonstrate that, although substrates for both subtypes are found in both junctional and free SR, PKC alpha and PKC beta do not show differences in selectivity towards these substrates.
Collapse
Affiliation(s)
- B G Allen
- Division of Pharmacology and Toxicology, Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, Canada
| | | |
Collapse
|
9
|
Przyklenk K, Sussman MA, Simkhovich BZ, Kloner RA. Does ischemic preconditioning trigger translocation of protein kinase C in the canine model? Circulation 1995; 92:1546-57. [PMID: 7664439 DOI: 10.1161/01.cir.92.6.1546] [Citation(s) in RCA: 72] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
BACKGROUND Brief episodes of ischemia protect or "precondition" the heart and reduce the size of infarcts caused by subsequent sustained coronary artery occlusion, yet the mechanisms responsible for this cardioprotection remain unresolved. We tested the theory that translocation of protein kinase C (PKC) to the myocyte membranes, initiated in response to brief preconditioning ischemia and manifest during the initial minutes of the sustained occlusion, mediates this phenomenon by attempting to (1) blunt the cardioprotective effects of preconditioning by administration of the PKC inhibitors H-7 and polymyxin B, (2) visualize by fluorescence staining and confocal microscopy changes in the amount or location of PKC, and (3) quantify by incorporation of 32P into PKC-specific peptide changes in the subcellular distribution of PKC in preconditioned versus control hearts. METHODS AND RESULTS In the first three limbs of this study, anesthetized open-chest dogs underwent four 5-minute episodes of preconditioning ischemia or a comparable control period before 1 hour of sustained occlusion and 4 to 5 hours of reperfusion. Collateral blood flow was assessed with radioactive microspheres; area at risk (AR) was delineated by injection of blue dye; and the area of necrosis (AN) was measured by tetrazolium staining. AN/AR was smaller in preconditioned versus control dogs that received no treatment (6 +/- 2% versus 19 +/- 3%, P < .01), H-7 (2 +/- 2% versus 14 +/- 5%, P < .02), or polymyxin B (10 +/- 3% versus 29 +/- 5%, P < .01) during the preconditioning or control period. Additional dogs underwent four 5-minute episodes of ischemia, with biopsies obtained at baseline and after the first and fourth occlusions. Frozen sections were stained with a fluorescent probe for active PKC and viewed with confocal microscopy. No differences in the intensity or distribution of fluorescence staining were observed after brief ischemia compared with baseline. Finally, myocardial samples were obtained from dogs subjected to four 5-minute episodes of preconditioning ischemia and time-matched sham-operated controls. Incorporation of 32P into PKC-specific peptide revealed no quantitative difference in the subcellular distribution of PKC between control and preconditioned cohorts. CONCLUSIONS H-7 and polymyxin B did not blunt the reduction in infant size achieved with ischemic preconditioning. Neither fluorescence staining and confocal microscopy nor biochemical quantification revealed evidence of preconditioning-induced translocation of PKC to the cell membranes. These results fail to support the hypothesis that translocation of PKC, triggered by preconditioning ischemia, is an important mechanism for the reduction in infarct size seen with preconditioning in the dog model.
Collapse
Affiliation(s)
- K Przyklenk
- Heart Institute, Hospital of the Good Samaritan, Los Angeles, CA 90017, USA
| | | | | | | |
Collapse
|
10
|
Williams S, Mesaeli N, Panagia V. Phospholipase signalling pathways in thyroxine-induced cardiac hypertrophy. Ann N Y Acad Sci 1995; 752:187-91. [PMID: 7755257 DOI: 10.1111/j.1749-6632.1995.tb17421.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- S Williams
- Division of Cardiovascular Sciences, St. Boniface General Hospital Research Centre, Winnipeg, Manitoba, Canada
| | | | | |
Collapse
|
11
|
Gu X, Bishop SP. Increased protein kinase C and isozyme redistribution in pressure-overload cardiac hypertrophy in the rat. Circ Res 1994; 75:926-31. [PMID: 7923639 DOI: 10.1161/01.res.75.5.926] [Citation(s) in RCA: 120] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Protein kinase C (PKC) activity and isozyme distribution were evaluated during development of pressure-overload-induced cardiac hypertrophy. Three-week-old rats were loosely banded on the ascending aorta (left ventricular hypertrophy [LVH] group). Two weeks later, when left ventricular mass was 50% greater than in the sham-operated control group and cardiac mass was still rapidly increasing beyond that of normal growth, PKC activity and [3H]phorbol 12,13-dibutyrate (PDBu) binding capacity were determined. In LVH, PKC activity was 119 +/- 14%, 158 +/- 17%, and 152 +/- 9% of the control value in cytosol, membrane, and nuclear-cytoskeletal fractions, respectively (n = 9 or 10). [3H]PDBu binding assay revealed increased PKC concentration in LVH cytosolic (control, 0.51 +/- 0.06 pmol/L per milligram; LVH, 0.78 +/- 0.09 pmol/L per milligram; n = 5; P < .05) and membrane fractions (control, 1.33 +/- 0.15; LVH, 2.32 +/- 0.39; n = 5; P < .05). Scatchard analysis indicated no difference in Kd values between control and LVH groups. Immunoblot analysis using PKC isoform-specific antibodies showed that both Ca(2+)-dependent (alpha and beta) and Ca(2+)-independent (delta, epsilon, and zeta) isoforms were present in the left ventricle. Compared with the control value, there was increased concentration in the membrane and nuclear-cytoskeletal fractions for beta 1,2 and epsilon and in the cytosol for beta 1,2. PKC-delta could be detected only in the nuclear-cytoskeletal fraction and was not changed in LVH. PKC-alpha and -zeta were present in all three fractions but were not altered in LVH. These data indicate that PKC activity and concentration increase during development of LVH induced by pressure overload. The increased PKC isozymes were mainly limited to PKC-beta 1,2 and PKC-epsilon, and the increase was present mainly in the membrane and nuclear-cytoskeletal fractions.
Collapse
Affiliation(s)
- X Gu
- Department of Pathology, University of Alabama at Birmingham 35294-0019
| | | |
Collapse
|
12
|
Pucéat M, Hilal-Dandan R, Strulovici B, Brunton L, Brown J. Differential regulation of protein kinase C isoforms in isolated neonatal and adult rat cardiomyocytes. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(19)89480-2] [Citation(s) in RCA: 205] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
|
13
|
The active site substrate specificity of protein kinase C. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(17)34039-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
|
14
|
|
15
|
Mattila P, Majuri ML, Tiisala S, Renkonen R. Expression of six protein kinase C isotypes in endothelial cells. Life Sci 1994; 55:1253-60. [PMID: 7934626 DOI: 10.1016/0024-3205(94)90063-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Protein kinase C (PKC) family is an important regulatory element in signal transduction, cellular regulation and tumor promotion. The classical PKC isotypes (alpha, beta and gamma) are Ca(2+)-dependent and can be activated by diacylglycerol. The novel isotypes, PKC delta, PKC epsilon, PKC eta (L) and PKC theta, are Ca(2+)-independent, whereas the two atypical PKCs (zeta and lambda) lack the Ca(2+)-binding region and are not activated by diacylglycerol. Here we show that cultured human endothelial cell line EA.hy926 as well as freshly isolated human umbilical vein endothelial cells express members of all PKC subfamilies. No traces of PKC gamma or delta were detected in endothelial cells. On the contrary the classical PKCs (alpha and beta), the novel PKC epsilon, as well as the atypical PKC zeta are present at the mRNA level in human endothelial cells and the corresponding proteins are also detected by immunoblotting.
Collapse
Affiliation(s)
- P Mattila
- Department of Bacteriology and Immunology, University of Helsinki, Finland
| | | | | | | |
Collapse
|
16
|
García-Paramio P, Carmena MJ, Román F, Colás B, Prieto JC. Characterization of protein kinase C in rat and human prostates. Biosci Rep 1993; 13:313-23. [PMID: 8204801 DOI: 10.1007/bf01150476] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
The properties of protein kinase C (PKC) activity have been studied in cytosolic and membrane fractions from rat and human prostate. Ion exchange chromatography indicated the existence of different PKC isoforms, PKC from rat ventral prostate behaved as a classical Ca(2+)- and phospholipid-dependent enzyme and was activated by 1,2-diacylglycerol as well as by high concentrations of arachidonic acid. PKC activity in the cytosolic fraction was higher and presented different cofactor requirements than that in the membrane fraction. PKC from human benign hyperplastic prostate was also phospholipid dependent, activated by tumor-promotong phorbol esters, and appeared to belong to the group of PKC isozymes which lack Ca2+ sensitivity. Human prostatic PKC activity appeared to be of similar nature in both membrane and cytosolic fractions but the specific activity was higher in the particulate preparation which could be related to the stage of endogenous activation of the enzyme. These results extend previous observations in rat ventral prostate and present evidences on the human counterpart. Forthcoming experiments are needed to establish the exact nature of PKC isozymes and their physiological and pathophysiological role in this gland.
Collapse
Affiliation(s)
- P García-Paramio
- Departamento de Bioquímica y Biología Molecular, Universidad de Alcalá, Alcalá de Henares, Spain
| | | | | | | | | |
Collapse
|
17
|
Kohout TA, Rogers TB. Use of a PCR-based method to characterize protein kinase C isoform expression in cardiac cells. THE AMERICAN JOURNAL OF PHYSIOLOGY 1993; 264:C1350-9. [PMID: 7684564 DOI: 10.1152/ajpcell.1993.264.5.c1350] [Citation(s) in RCA: 55] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Molecular cloning has identified at least nine unique isozymes of protein kinase C (PKC) designated alpha, beta I, beta II, gamma, delta, epsilon, zeta, and eta/L, with the recent addition of the theta-isoform. Previous attempts to characterize PKC isoform expression in heart have been limited by low levels of protein and perhaps by the presence of novel isoforms. Thus to critically examine the diversity of PKC expression in cardiac cells, we developed a reverse transcriptase-polymerase chain reaction (RT-PCR) approach that would amplify regions of the target cDNA of all the PKC isozymes in a single reaction. Degenerate oligonucleotide primers were designed to recognize sequences in the conserved regions of the PKC sequence motif: the cysteine-rich and the ATP-binding regions. Amplification of target PKC cDNA sequences resulted in PCR products with unique sizes and restriction digestion properties. The system was validated by identifying PCR products that correspond to all of the PKC isoform transcripts, except PKC-zeta, in a single reaction with cDNA derived from hippocampus. Cardiac cDNA was RT-PCR amplified, and the products were analyzed by a combination of restriction mapping and DNA sequencing that revealed the presence of only the alpha, delta, epsilon, and eta isoforms in adult rat cardiac myocytes and cultured neonatal ventricular myocytes. A unique nondegenerate primer pair was synthesized to recognize PKC-zeta cDNA. Results with these primers show that PKC-zeta is present in both cardiac myocyte preparations as well. The RT-PCR method developed here is an efficient approach that is broadly useful to examine PKC expression in many tissues, including the identification of potentially novel isoforms.(ABSTRACT TRUNCATED AT 250 WORDS)
Collapse
Affiliation(s)
- T A Kohout
- Department of Biological Chemistry, University of Maryland School of Medicine, Baltimore 21201
| | | |
Collapse
|
18
|
Münster PN, Weingart R. Effects of phorbol ester on gap junctions of neonatal rat heart cells. Pflugers Arch 1993; 423:181-8. [PMID: 8321620 DOI: 10.1007/bf00374392] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Myocytes were isolated from the ventricles of neonatal rat hearts and cultured for 1-3 days. Newly formed cell pairs were used to examine the conductance of gap junctions, gj. Measurements were performed using a dual voltage-clamp method in conjunction with a whole-cell, tight-seal recording. Exposure to the phorbol ester 12-O-tetradecanoylphorbol-13-acetate (TPA, 100-160 nM) led to a decrease in gj. Single-channel events recorded immediately before complete uncoupling yielded a single-channel conductance, gamma j, of 40.5 pS, implying that TPA affects the channel kinetics rather than gamma j. TPA-induced uncoupling was observed at subphysiological levels of cytosolic Ca2+ (pipette solution = 18 nM), not at physiological levels (pipette solution = 170 nM). The effects of TPA could not be mimicked by 250 microM 1-oleoyl-2-acetyl-glycerol (OAG). Preincubation with TPA (up to 24 h) revealed no changes in gj attributable to down-regulation of protein kinase C, PKC. Pretreatment with PKC inhibitors, staurosporine or PKCI, prevented the TPA-dependent decrease in gj. TPA-dependent uncoupling was not impaired by 4-bromophenacyl bromide, an inhibitor of phospholipase A2, PLA2; conversely, an arachidonic acid-dependent decrease in gj was not prevented by PKCI. This suggests that gj regulation does not involve an interaction between PLA2 and PKC.
Collapse
Affiliation(s)
- P N Münster
- Department of Physiology, University of Bern, Switzerland
| | | |
Collapse
|
19
|
Bogoyevitch MA, Parker PJ, Sugden PH. Characterization of protein kinase C isotype expression in adult rat heart. Protein kinase C-epsilon is a major isotype present, and it is activated by phorbol esters, epinephrine, and endothelin. Circ Res 1993; 72:757-67. [PMID: 8443867 DOI: 10.1161/01.res.72.4.757] [Citation(s) in RCA: 169] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The pattern of protein kinase C (PKC) isotype expression in whole extracts of dispersed, freshly isolated adult rat ventricular myocytes and adult rat heart ventricle was examined by immunoblot analysis using antisera specific for PKC-alpha, -beta 1, -gamma, -delta, -epsilon, -zeta, or -eta isotypes. This analysis revealed significant levels of expression of the Ca(2+)-independent isotype PKC-epsilon, which was detected as band of 97-kd molecular mass. PKC-zeta was detected principally as a 66-kd band that probably represented a proteolytic product of the holoenzyme. PKC-eta was detected only in whole ventricle as a doublet at 75 and 81 kd and was therefore probably present in nonmyocytic cells. PKC-alpha, -beta 1, -gamma, and -delta could not be detected. Because of our inability to detect PKC-alpha, -beta 1, -gamma, and -delta in whole extracts, PKC isotypes were partially purified from whole heart by DEAE Sepharose chromatography. PKC-alpha, -beta 1, -gamma, and -delta could still not be detected in the appropriate fractions. All PKC isotypes were detectable in appropriate positive control extracts (brain or certain cultured cell lines). In unstimulated isolated cardiomyocytes, the majority (80-95%) of the PKC-epsilon immunoreactivity was present in the soluble fraction of the extract. On exposure of the cardiomyocytes to 1 microM phorbol 12-myristate 13-acetate (PMA), PKC-epsilon undergoes a rapid (< 30 seconds), sustained (at least 60 minutes), and virtually complete association with the Triton X-100-soluble membrane fraction. There was an associated loss of PKC-epsilon from the soluble fraction. The EC50 for PMA of the translocation event was 15-37 nM. Exposure of cardiomyocytes to 1 microM 4 beta-phorbol 12,13-didecanoate or 1 microM phorbol 12,13-dibutyrate also resulted in translocation of PKC-epsilon to the membrane fraction, whereas exposure to 1 microM 4 alpha-phorbol 12,13-didecanoate was without effect. PKC-epsilon also translocated on exposure of cardiomyocytes to 50 microM epinephrine or 100 nM endothelin-1. However, in both cases, the extent of translocation was significantly less than that after exposure to PMA. We conclude that interventions that lead to hypertrophy of cardiomyocytes (phorbol esters, epinephrine, and endothelin-1) activate PKC-epsilon.
Collapse
|
20
|
Church DJ, Braconi S, Vallotton MB, Lang U. Protein kinase C-mediated phospholipase A2 activation, platelet-activating factor generation and prostacyclin release in spontaneously beating rat cardiomyocytes. Biochem J 1993; 290 ( Pt 2):477-82. [PMID: 8452537 PMCID: PMC1132298 DOI: 10.1042/bj2900477] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The expression of protein kinase C (PKC) isoenzymes and the effects of PKC activation on myocardial phospholipase A2 (PLA2) activity, platelet-activating factor (PAF) generation and eicosanoid release were studied in spontaneously beating cultured rat cardiomyocytes. Western blotting analysis indicated that these cells contain PKC alpha, beta, delta and zeta, but not PKC gamma or epsilon. Stimulation of cardiomyocytes with 4 beta-phorbol 12-myristate 13-acetate (PMA) led to a rapid increase in particulate-bound PKC activity, a response attributed to the activation of alpha-, delta- and zeta- type PKCs but not beta-type PKC. Translocation of PKC alpha, delta and zeta was accompanied by simultaneous increases in cellular lysophosphatidylcholine (lyso-PC), PAF, 15(S)-hydroxy-5,8,-11,13-eicosatetraenoic acid (15-HETE), prostaglandin E2 (PGE2) and prostacyclin (PGI2) generation, suggesting that one or more of these isoenzymes directly or indirectly activates a PLA2 in these cells. Confirming this, 4 beta-phorbol 12-monoacetate and 4 alpha-phorbol had no effect on cellular eicosanoid formation, while the PMA-induced response was fully abolished both in the presence of the PKC inhibitors staurosporine and CGP 41251 and in PKC-down-regulated cells. PKC alpha, delta and/or zeta therefore appear to play an important role in the PMA-mediated activation of cardiomyocyte PLA2, an event leading to subsequent production of PGI2, PGE2, 15-HETE, lyso-PC and PAF in this tissue.
Collapse
Affiliation(s)
- D J Church
- Department of Medicine, Geneva University Hospital, Switzerland
| | | | | | | |
Collapse
|
21
|
Cserhåti T, Szögyi M. Interaction of phospholipids with proteins and peptides. New advances III. THE INTERNATIONAL JOURNAL OF BIOCHEMISTRY 1993; 25:123-46. [PMID: 8444311 DOI: 10.1016/0020-711x(93)90001-u] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
1. The review deals with the recent achievements in the study of the various interactions of phospholipids with proteins and peptides. 2. The interactions are classified according to the hydrophobic, hydrophilic or mixed character of the interactive forces. 3. The effect of the interaction on the structure and biological activity of the interacting molecules is also discussed.
Collapse
Affiliation(s)
- T Cserhåti
- Central Research Institute for Chemistry, Hungarian Academy of Sciences, Budapest
| | | |
Collapse
|
22
|
|
23
|
Langlands JM, Diamond J. Translocation of protein kinase C in bovine tracheal smooth muscle strips: the effect of methacholine and isoprenaline. Eur J Pharmacol 1992; 227:131-8. [PMID: 1330645 DOI: 10.1016/0922-4106(92)90120-k] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Investigations into the mechanisms involved in the contraction of smooth muscle have suggested that the generation of diacylglycerol and the activation of protein kinase C (PKC) may be important in the generation or maintenance of smooth muscle tone. The present study examined the possible role of PKC in the contraction of bovine tracheal smooth muscle. Methacholine (10 microM) induced a rapid elevation in PKC activity associated with the membrane fraction. PKC levels were significantly elevated in the membrane fraction 30 s after agonist addition, reached a maximum at 1 min and then declined to and remained at a lower level which was still elevated above basal. A concomitant decrease in cytosolic PKC activity of smaller magnitude was observed during this period of stimulation. This methacholine-induced re-distribution of PKC from the cytosol to the membrane was concentration-dependent and was blocked by atropine. Pre-treatment of tissues for 2 min with 100 microM isoprenaline prevented both the re-distribution of PKC and the contraction produced by 1 microM methacholine. Addition of 1 microM isoprenaline to tissues pre-contracted with 1 microM methacholine reversed the re-distribution of PKC produced during contraction and completely relaxed the tissues. Thus, under these conditions, translocation of PKC from the cytosol to the membrane seems to be well correlated with contractions of bovine tracheal smooth muscle. Whether the PKC translocation is responsible for the observed changes in muscle tone or whether the enzyme translocation is a result of drug-induced changes in [Ca2+]i, remains to be determined.
Collapse
Affiliation(s)
- J M Langlands
- Division of Pharmacology and Toxicology, Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, Canada
| | | |
Collapse
|
24
|
Olivier M, Brownsey RW, Reiner NE. Defective stimulus-response coupling in human monocytes infected with Leishmania donovani is associated with altered activation and translocation of protein kinase C. Proc Natl Acad Sci U S A 1992; 89:7481-5. [PMID: 1323839 PMCID: PMC49734 DOI: 10.1073/pnas.89.16.7481] [Citation(s) in RCA: 104] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Stimulus-response coupling through protein kinase C (PKC) was shown to be defective in mononuclear phagocytes (M phi) infected with Leishmania donovani. Phorbol 12-myristate 13-acetate (PMA)-induced oxidative burst activity and protein phosphorylation were markedly attenuated in infected M phi. These results were not explained either by quantitative alterations in amounts of PKC or by altered phorbol ester binding but were related to defects in kinase activation. Analysis in vitro of the kinetic properties of PKC from infected M phi revealed an approximately 2-fold increase in the concentration of 1,2-dioleoyl-rac-glycerol required to achieve half-maximal kinase activation. Evidence for abnormal PKC activation in vivo was reflected by attenuation of PMA-induced translocation of enzyme to the particulate fraction of infected cells. These results provide direct evidence that infection with Leishmania inhibits activation of, and therefore intracellular signaling dependent on, PKC. Inhibition of stimulus-response coupling through PKC provides a basis for understanding impairment of cellular activation by Leishmania and may contribute to chronic infection.
Collapse
Affiliation(s)
- M Olivier
- Department of Medicine, University of British Columbia Faculty of Medicine, Vancouver, Canada
| | | | | |
Collapse
|
25
|
Sanghera JS, Charlton LA, Paddon HB, Pelech SL. Purification and characterization of echinoderm casein kinase II. Regulation by protein kinase C. Biochem J 1992; 283 ( Pt 3):829-37. [PMID: 1590772 PMCID: PMC1130961 DOI: 10.1042/bj2830829] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Casein kinase II (CKII) is one of several protein kinases that become activated before germinal-vesicle breakdown in maturing sea-star oocytes. Echinoderm CKII was purified over 11,000-fold with a recovery of approximately 10% by sequential fractionation of the oocyte cytosol on tyrosine-agarose, heparin-agarose, casein-agarose and MonoQ. The purified enzyme contained 45, 38 and 28 kDa polypeptides, which corresponded to its alpha, alpha' and beta subunits respectively. The beta-subunit was autophosphorylated on one major tryptic peptide on serine residues, whereas the alpha'-subunit incorporated phosphate into at least two tryptic peptides primarily on threonine residues. Western-blotting analysis of sea-star oocyte extracts with two different anti-peptide antibodies that recognized conserved regions of the alpha-subunit indicated that the protein levels of the alpha- and alpha'-subunits of CKII were unchanged during oocyte maturation. The purified CKII was partly inactivated (by 25%) by preincubation with protein-serine/threonine phosphatase 2A, but protein-tyrosine phosphatases had no effect. The beta-subunit of CKII was phosphorylated on a serine residue(s) up to 0.54 mol of P/mol of beta-subunit by purified protein kinase C, and this correlated with a 1.5-fold enhancement of its phosphotransferase activity with phosvitin as a substrate. CKII was not a substrate for the maturation-activated myelin basic protein kinase p44mpk from sea-star oocytes, nor for cyclic-AMP-dependent protein kinase. These studies point to possible regulation of CKII by protein phosphorylation.
Collapse
Affiliation(s)
- J S Sanghera
- Department of Medicine, University of British Columbia, Vancouver, Canada
| | | | | | | |
Collapse
|