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

We investigated whether in the isolated perfused rat heart acute pressure overload may affect the expression of genes involved in calcium homeostasis, namely sarcolemmal L-type Ca2+ channel, Na+/Ca2+ exchanger, sarcoplasmic reticulum Ca2+-ATPase, phospholamban, and ryanodine receptor. Hearts were subjected to 210 min of perfusion under the following conditions: (i) standard working heart perfusion with preload and afterload set at 20 and 100 cm, respectively; (ii) working heart perfusion at high afterload (180 cm); (iii) retrograde infusion of St. Thomas' Hospital cardioplegic solution. In all models gene expression was determined by RT-PCR. Significant decrease in the expression of the sarcoplasmic reticulum Ca2+-ATPase gene was observed in the high afterload group. No significant change in the expression of any other gene was observed in any group. The reported effect was not detected after 60 min of perfusion, and it was blunted in the presence of the protein kinase C inhibitor chelerythrine, while the calcineurin inhibitor cyclosporin A was ineffective. In conclusion, the sarcoplasmic reticulum Ca2+-ATPase gene is downregulated after short-term (210 min) perfusion at high afterload, possibly through a protein kinase C-dependent pathway. This mechanism might play a relevant pathophysiological role in the response to pressure overload and in the development of hypertrophy.
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PMID:Short-term effects of pressure overload on the expression of genes involved in calcium homeostasis. 1836 4

Recently, we identified a novel signaling pathway involving Epac, Rap, and phospholipase C (PLC)epsilon that plays a critical role in maximal beta-adrenergic receptor (betaAR) stimulation of Ca2+-induced Ca2+ release (CICR) in cardiac myocytes. Here we demonstrate that PLCepsilon phosphatidylinositol 4,5-bisphosphate hydrolytic activity and PLCepsilon-stimulated Rap1 GEF activity are both required for PLCepsilon-mediated enhancement of sarcoplasmic reticulum Ca2+ release and that PLCepsilon significantly enhances Rap activation in response to betaAR stimulation in the heart. Downstream of PLCepsilon hydrolytic activity, pharmacological inhibition of PKC significantly inhibited both betaAR- and Epac-stimulated increases in CICR in PLCepsilon+/+ myocytes but had no effect in PLCepsilon-/- myocytes. betaAR and Epac activation caused membrane translocation of PKCepsilon in PLCepsilon+/+ but not PLCepsilon-/- myocytes and small interfering RNA-mediated PKCepsilon knockdown significantly inhibited both betaAR and Epac-mediated CICR enhancement. Further downstream, the Ca2+/calmodulin-dependent protein kinase II (CamKII) inhibitor, KN93, inhibited betaAR- and Epac-mediated CICR in PLCepsilon+/+ but not PLCepsilon-/- myocytes. Epac activation increased CamKII Thr286 phosphorylation and enhanced phosphorylation at CamKII phosphorylation sites on the ryanodine receptor (RyR2) (Ser2815) and phospholamban (Thr17) in a PKC-dependent manner. Perforated patch clamp experiments revealed that basal and betaAR-stimulated peak L-type current density are similar in PLCepsilon+/+ and PLCepsilon-/- myocytes suggesting that control of sarcoplasmic reticulum Ca2+ release, rather than Ca2+ influx through L-type Ca2+ channels, is the target of regulation of a novel signal transduction pathway involving sequential activation of Epac, PLCepsilon, PKCepsilon, and CamKII downstream of betaAR activation.
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PMID:Epac and phospholipase Cepsilon regulate Ca2+ release in the heart by activation of protein kinase Cepsilon and calcium-calmodulin kinase II. 1895 19

Protein kinase C (PKC) is known to regulate ryanodine receptor (RyR)-mediated local Ca(2+) signaling (Ca(2+) spark) in airway and vascular smooth muscle cells (SMCs), but its specific molecular mechanisms and functions still remain elusive. In this study, we reveal that, in airway SMCs, specific PKCepsilon peptide inhibitor and gene deletion significantly increased the frequency of Ca(2+) sparks, and decreased the amplitude of Ca(2+) sparks in the presence of xestospogin-C to eliminate functional inositol 1,4,5-triphosphate receptors. PKCepsilon activation with phorbol-12-myristate-13-acetate significantly decreased Ca(2+) spark frequency and increased Ca(2+) spark amplitude. The effect of PKCepsilon inhibition or activation on Ca(2+) sparks was completely lost in PKCepsilon(-/-) cells. PKCepsilon inhibition or PKCepsilon activation was unable to affect Ca(2+) sparks in RyR1(-/-) and RyR1(+/-) cells. Modification of RyR2 activity by FK506-binding protein 12.6 homozygous or RyR2 heterozygous gene deletion did not prevent the effect of PKCepsilon inhibition or activation. RyR3 homogenous gene deletion did not block the effect of PKCepsilon inhibition and activation, either. PKCepsilon inhibition promotes agonist-induced airway muscle contraction, whereas PKCepsilon activation produces an opposite effect. Taken together, these results indicate that PKCepsilon regulates Ca(2+) sparks by specifically interacting with RyR1, which plays an important role in the control of contractile responses in airway SMCs.
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PMID:Protein kinase C-epsilon regulates local calcium signaling in airway smooth muscle cells. 1901 Nov 60

Hypertension develops in many patients receiving the immunosuppressive drug tacrolimus (FK506). One possible mechanism for hypertension is a reduction in vasodilatory nitric oxide. We found that tacrolimus and a calcineurin autoinhibitory peptide significantly decreased vascular calcineurin activity; however, only tacrolimus altered intracellular calcium release in mouse aortic endothelial cells. In mouse aortas, incubation with tacrolimus increased protein kinase C activity and basal endothelial nitric oxide synthase phosphorylation at threonine 495 but reduced basal and agonist-induced endothelial nitric oxide synthase phosphorylation at serine 1177, a mechanism known to inhibit synthase activity. While this decreased nitric oxide production and endothelial function, the calcineurin autoinhibitory peptide had no such effects. Inhibition of ryanodine receptor opening or protein kinase C blocked the effects of tacrolimus. Since it is known that the FK506 binding protein (FKBP12/12.6) interacts with the ryanodine receptor to regulate calcium release, we propose this as the mechanism by which tacrolimus alters intracellular calcium and endothelial nitric oxide synthase rather than by its effect on calcineurin. Our study shows that prevention of the tacrolimus-induced intracellular calcium leak may attenuate endothelial dysfunction and the consequent hypertension.
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PMID:Tacrolimus reduces nitric oxide synthase function by binding to FKBP rather than by its calcineurin effect. 1917 55

This review addresses the localized regulation of voltage-gated ion channels by phosphorylation. Comprehensive data on channel regulation by associated protein kinases, phosphatases, and related regulatory proteins are mainly available for voltage-gated Ca2+ channels, which form the main focus of this review. Other voltage-gated ion channels and especially Kv7.1-3 (KCNQ1-3), the large- and small-conductance Ca2+-activated K+ channels BK and SK2, and the inward-rectifying K+ channels Kir3 have also been studied to quite some extent and will be included. Regulation of the L-type Ca2+ channel Cav1.2 by PKA has been studied most thoroughly as it underlies the cardiac fight-or-flight response. A prototypical Cav1.2 signaling complex containing the beta2 adrenergic receptor, the heterotrimeric G protein Gs, adenylyl cyclase, and PKA has been identified that supports highly localized via cAMP. The type 2 ryanodine receptor as well as AMPA- and NMDA-type glutamate receptors are in close proximity to Cav1.2 in cardiomyocytes and neurons, respectively, yet independently anchor PKA, CaMKII, and the serine/threonine phosphatases PP1, PP2A, and PP2B, as is discussed in detail. Descriptions of the structural and functional aspects of the interactions of PKA, PKC, CaMKII, Src, and various phosphatases with Cav1.2 will include comparisons with analogous interactions with other channels such as the ryanodine receptor or ionotropic glutamate receptors. Regulation of Na+ and K+ channel phosphorylation complexes will be discussed in separate papers. This review is thus intended for readers interested in ion channel regulation or in localization of kinases, phosphatases, and their upstream regulators.
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PMID:Supramolecular assemblies and localized regulation of voltage-gated ion channels. 1934 11

Using fura-2-acetoxymethyl ester (AM) fluorescence imaging and patch clamp techniques, we found that endothelin-1 (ET-1) significantly elevated the intracellular calcium level ([Ca(2+)](i)) in a dose-dependent manner and activated the L-type Ca(2+) channel in cardiomyocytes isolated from rats. The effect of ET-1 on [Ca(2+)](i) elevation was abolished in the presence of the ET(A) receptor blocker BQ123, but was not affected by the ET(B) receptor blocker BQ788. ET-1-induced an increase in [Ca(2+)](i), which was inhibited 46.7% by pretreatment with a high concentration of ryanodine (10 micromol/L), a blocker of the ryanodine receptor. The ET-1-induced [Ca(2+)](i) increase was also inhibited by the inhibitors of protein kinase A (PKA), protein kinase C (PKC) and angiotensin type 1 receptor (AT1 receptor). We found that ET-1 induced an enhancement of the amplitude of the whole cell L-type Ca(2+) channel current and an increase of open-state probability (NPo) of an L-type single Ca(2+) channel. BQ123 completely blocked the ET-1-induced increase in calcium channel open-state probability. In this study we demonstrated that ET-1 regulates calcium overload through a series of mechanisms that include L-type Ca(2+) channel activation and Ca(2+)-induced Ca(2+) release (CICR). ETA receptors, PKC, PKA and AT1 receptors may also contribute to this pathway.
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PMID:Endothelin-1 induces intracellular [Ca2+] increase via Ca 2+ influx through the L-type Ca2+ channel, Ca 2+ -induced Ca2+ release and a pathway involving ET A receptors, PKC, PKA and AT1 receptors in cardiomyocytes. 1938 62

This study investigated the role of the endoplasmic reticulum pathway in apoptosis induced by trichlorfon in SH-SY5Y human neuroblastoma cells. Flow cytometric analysis demonstrated that trichlorfon and its degradation product dichlorvos-induced apoptosis in a dose-dependent manner and Hoechst 33342 staining experiments revealed trichlorfon/dichlorvos-induced nucleus condensation. Western blot analysis indicated decreased expression of caspase-12 and increased activated caspase-12 in trichlorfon-treated cells compared to a control, suggesting that trichlorfon may induce apoptosis in SH-SY5Y partly via the endoplasmic reticulum. Intracellular Ca(2+) level ([Ca(2+)](i)) in SH-SY5Y cells increased after treatment with trichlorfon but was significantly reduced by pre-treatment with a combination of a calcium channel blocker, an inositol trisphosphate receptor inhibitor, and a ryanodine receptor inhibitor. Percent apoptosis and activated caspase-3 and caspase-12 decreased in pre-treated cells compared to those treated with trichlorfon alone. Trichlorfon-induced apoptosis was also inhibited by the protein kinase C activator, phorbol 12-myristate 13-acetate (PMA). These results suggest that endoplasmic reticulum stress, which is related to calcium, may be involved in the cytotoxicity of trichlorfon.
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PMID:Trichlorfon induces apoptosis in SH-SY5Y neuroblastoma cells via the endoplasmic reticulum? 1963 81

To investigate the influence of breviscapine on the cardiac structure and function in diabetic cardiomyopathy rats as well as the expression of protein kinase C (PKC) and Ca(2+)-cycling proteins expression. Diabetes was induced in male Sprague-Dawley rats by a single intraperitoneal injection of streptozotocin and the control rats were injected with saline. After the induction of diabetes for 4 weeks, the animals were divided into different groups: (1) normal rats as control; (2) diabetic rats; (3) diabetic rats with administration of breviscapine (10 or 25 mg kg(-1) day(-2)). After treatment with breviscapine for 6 weeks, the invasive cardiac function and echocardiographic parameters were measured, and heart tissue was obtained for electron microscope study. The expression of protein kinase C (PKC) and calcium handling regulators, such as protein phosphatase inhibitor-1 (PPI-1), phospholamban (PLB) and Ca(2+)-ATPase (SERCA-2), ryanodine receptor (RyR) were detected by western blot or RT-PCR. The activity of SERCA-2 was measured using Ca(2+)-ATPase kit. Diabetic rats showed impaired cardiac structure and function compared with control rats. The expression of PKC, PLB increased significantly, while the PPI-1, SERCA-2 and RyR expression decreased. Treatment with breviscapine could reverse the cardiac dysfunction and structure changes in diabetic cardiomyopathy rats, and decrease the expression of PKC and PLB, as well as increase the expression of PPI-1, SERCA-2 and RyR. The protective effect of breviscapine was dose related. This study showed that breviscapine could regulate the expression of PKC, PPI-1, PLB and SERCA-2 and have protective effect on diabetic cardiomyopathy.
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PMID:Breviscapine ameliorates cardiac dysfunction and regulates the myocardial Ca(2+)-cycling proteins in streptozotocin-induced diabetic rats. 1988 1

Hydrogen sulfide (H(2)S) is now known as a new biological mediator. In the present study, the effects of H(2)S on intracellular calcium ([Ca(2+)](i)) in neuronal SH-SY5Y cells was investigated. In SH-SY5Y neuronal cells, NaHS, a H(2)S donor, concentration-dependently increased [Ca(2+)](i). The H(2)S-induced Ca(2+) elevation was significantly attenuated by EGTA-treated calcium-free Krebs' solution. This elevation was also reduced by antagonists of L-type (verapamil and nifedipine), T-type (mibefradil) calcium channels and N-methyl-d-aspartate receptor (MK-801, AP-5 and ifenprodil). A 90% reduction in H(2)S-induced [Ca(2+)](i) elevation was found in cells pretreated with combination of all three kinds of inhibitors. Depletion of intracellular Ca(2+) store with thapsigargin or cyclopiazonic acid or blockade of ryanodine receptor with ruthenium red significantly attenuated the effect of H(2)S on [Ca(2+)](i). Inhibition of protein kinase A (PKA), phospholipase C (PLC) and protein kinase C (PKC) suppressed the H(2)S-elevated [Ca(2+)](i), suggesting that H(2)S may regulate [Ca(2+)](i) via both PKA and PLC/PKC pathways. In conclusion, it was found in this study that H(2)S increased [Ca(2+)](i) in SH-SY5Y neuronal cells by increasing Ca(2+) influx via plasma membrane and in turn releasing calcium from intracellular calcium store. The findings in the present study provide the direct evidence that H(2)S may serve as a neuromodulator.
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PMID:Effect of hydrogen sulfide on intracellular calcium homeostasis in neuronal cells. 2002 67

JPs (junctophilins) contribute to the formation of junctional membrane complexes in muscle cells by physically linking the t-tubule (transverse-tubule) and SR (sarcoplasmic reticulum) membranes. In humans with HCM (hypertrophic cardiomyopathy), mutations in JP2 are linked to altered Ca2+ signalling in cardiomyocytes; however, the effects of these mutations on skeletal muscle function have not been examined. In the present study, we investigated the role of the dominant-negative JP2-S165F mutation (which is associated with human HCM) in skeletal muscle. Consistent with the hypertrophy observed in human cardiac muscle, overexpression of JP2-S165F in primary mouse skeletal myotubes led to a significant increase in myotube diameter and resting cytosolic Ca2+ concentration. Single myotube Ca2+ imaging experiments showed reductions in both the excitation-contraction coupling gain and RyR (ryanodine receptor) 1-mediated Ca2+ release from the SR. Immunoprecipitation assays revealed defects in the PKC (protein kinase C)-mediated phosphorylation of the JP2-S165F mutant protein at Ser165 and in binding of JP2-S165F to the Ca2+ channel TRPC3 (transient receptor potential cation canonical-type channel 3) on the t-tubule membrane. Therefore both the hypertrophy and altered intracellular Ca2+ signalling in the JP2-S165F-expressing skeletal myotubes can be linked to altered phosphorylation of JP2 and/or altered cross-talk among Ca2+ channels on the t-tubule and SR membranes.
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PMID:S165F mutation of junctophilin 2 affects Ca2+ signalling in skeletal muscle. 2009 64


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