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)

1. In order to define the electrophysiological mechanism(s) responsible for bradykinin (BK)-induced positive inotropic and chronotropic responses in isolated guinea-pig atria, effects of BK on the membrane currents were examined in isolated atrial cells using patch clamp techniques. 2. BK (0.1-1000 nM) increased the L-type Ca2+ current (I(Ca)), which was recorded from enzymatically-dissociated atrial myocytes by the nystatin-perforated patch method, in a concentration-dependent fashion, and the calculated EC50 value for increasing I(Ca) was 5.2 nM. In conventional ruptured patch experiments, BK inhibited the muscarinic acetylcholine receptor-operated K+ current (I(K.ACh)) that was activated by the muscarinic agonist carbachol (1 microM) with an EC50 value of 0.57 nM. Both the increase in I(Ca) and the decrease in I(K.ACh) were blocked by HOE140, a selective bradykinin B2 receptor antagonist. 3. The BK-induced inhibition of I(K.ACh) was significantly attenuated by staurosporine and calphostin C, protein kinase C inhibitors. In addition, the I(K.ACh) inhibition by BK was also attenuated by the tyrosine kinase inhibitor genistein or tyrphostin but not by daidzein, an inactive analogue of genistein. However, neither protein kinase C inhibitor nor tyrosine kinase inhibitor affected the BK-induced increase in I(Ca). 4. In the presence and absence of muscarinic stimulation, BK prolonged the action potential recorded from the atrial cells in the current clamp mode. 5. We conclude that BK increases I(Ca) and decreases I(K.ACh) in atrial cells, resulting in positive inotropic and chronotropic responses in atrial preparations. Protein kinase C activation, and possibly tyrosine kinase activation, may be involved in the B2-receptor-mediated I(K.ACh) inhibition.
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PMID:Bradykinin B2-receptor-mediated modulation of membrane currents in guinea-pig cardiomyocytes. 978

Biologically active kinin peptides are released from precursor kininogens by kallikreins. Kinins act on kinin receptors to mediate diverse biological functions including smooth muscle contraction, inflammation, pain and mitogenicity. All components of the kallikrein-kinin system exist in human male genital secretions suggesting that these molecules participate in physiological and pathophysiological genitourinary function. The objective of this study was to assess the consequences of kinin action on prostate cells. Primary cultures of prostate secretory epithelial (PE) and prostate fibromuscular stromal (PS) cells were established from human prostate tissue. Transcripts encoding both the human B1 and B2 bradykinin receptor subtypes were detected in human prostate transition-zone tissue and in cultured cells by RT-PCR. In receptor binding assays, the B1 subtype predominated on PE cell membranes and the B2 subtype predominated on PS cell membranes. In PS cells, but not in PE cells, BK induced significant inositol phosphate accumulation and [3H]-thymidine uptake. These responses were mediated through the B2 receptor subtype. The use of signal transduction inhibitors indicated that mitogenic activation by BK occurred through both protein kinase C (PKC) and protein tyrosine kinase dependent mechanisms. PMA (phorbol 12-myristate 13-acetate) produced maximal [3H]-thymidine uptake by PS cells, resulted in cell elongation and caused the alpha-actin fibres present in PS smooth muscle cells to became organized into parallel arrays along the length of the elongated cells. In summary, the prostate contains a functional kallikrein-kinin system, which could be significant in physiological and pathophysiological prostate function.
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PMID:Mitogenic activation of human prostate-derived fibromuscular stromal cells by bradykinin. 1036 76

The relationship between cell proliferation, protein tyrosine phosphorylation, phosphotyrosine kinase activity and bradykinin receptor activation in rat mesangial cells was investigated. We demonstrated that bradykinin (BK), through the B2 receptor, induced a dose-dependent inhibition of mesangial cell proliferation stimulated by fetal calf serum. We next found that BK induced a dose-dependent inhibition of phospho-tyrosine kinase activity. Treatments with pertussis-toxin, inhibition of phospholipase C and protein kinase C inhibitors and chelation of free cytosolic calcium did not change the bradykinin-induced inhibition of phosphotyrosine kinase. Western blot analysis of phosphotyrosinated proteins demonstrated that BK reduced tyrosine phosphorylation of several proteins among which we identified the 125-focal adhesion kinase. Taken together, these data suggest for the first time that, in proliferating rat mesangial cells, B2 receptor stimulation is able to induce, via a pertussis insensitive pathway, the inhibition of tyrosine kinase activity and mesangial cell proliferation.
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PMID:Bradykinin-induced inhibition of cell proliferation and tyrosine kinase activity in rat mesangial cells. 1060 80

1. Pretreatment with ramiprilat, an angiotensin-converting enzyme (ACE) inhibitor, induced cardioprotection and its possible mechanism of action was investigated in guinea-pig Langendorff perfused heart. 2. Superoxide anion (*O2-), produced by hypoxanthine and xanthine oxidase, and the 1,1-diphenyl-2-picryl-hydrazyl (DPPH) free radical were used for triggering free radical injury in cardiac tissue. 3. 1,1-Diphenyl-2-picryl-hydrazyl and *O2- significantly reduced left ventricular developed pressure (LVDP), +/-dP/dt(max), heart rate and coronary flow. Left ventricular end-diastolic pressure (LVEDP) was elevated and lactate dehydrogenase (LDH) leakage and the formation of thiobarbituric acid-reactive substances (TBARS) formation were significantly increased. 4. Pretreatment with ramiprilat induced cardioprotection against DPPH and *O2- free radical injury. Cardiac functions (LVDP, LVEDP and +/-dP/dt(max)) were significantly improved. Both LDH and TBARS were reduced. 5. HOE 140 (a selective bradykinin B2 receptor antagonist), calphostin C (a protein kinase C (PKC) inhibitor) and indomethacin (a cyclo-oxygenase inhibitor) all abolished the cardiac protective effect of ramiprilat. However, N(G)-nitro-L-arginine methyl ester, a nitric oxide synthase inhibitor, had no effect. 6. In conclusion, ramiprilat pretreatment induces cardioprotection against either DPPH or *O2- free radical injury. The protective effect depends on activation of B2 receptors and PKC. Prostaglandin synthesis is also involved.
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PMID:Pretreatment with ramiprilat induces cardioprotection against free radical injury in guinea-pig isolated heart: involvement of bradykinin, protein kinase C and prostaglandins. 1077 22

Earlier studies have shown that activation of bradykinin B2 receptor triggers protein kinase C (PKC)-mediated cardioprotective mechanism in ischemic preconditioning (PC). In the present study, we examined whether the effector in this B2-receptor triggered pathway of PC is the ATP sensitive potassium (K(ATP)) channel in the mitochondria (mito-K(ATP) channel) or K(ATP) channel in the sarcolemma (sarc-K(ATP) channel). Isolated rabbit hearts were perfused with modified Krebs-Henseleit buffer in a Langendorff mode, and regional myocardial ischemia was induced by occluding a left coronary artery for 30 min and then reperfusing for 2 hours. Infarct size was determined by triphenyltetrazolium chloride staining and expressed as a percentage of area at risk (% IS/AR). Infusion of bradykinin (500 nmol/L) for 15 min prior to ischemia significantly reduced % IS/AR from 37.4 +/- 2.9 (SE) of the untreated controls to 12.0 +/- 3.3%. This protective effect of bradykinin was completely abolished by coinfusion of 5-hydroxydecanoate (5-HD, 50 micromol/L), a selective mito-K(ATP) channel blocker (% IS/AR = 44.2 +/- 6.4). In contrast, a high dose of HMR1098 (20 micromol/L), which is a newly developed sarc-K(ATP) channel selective blocker with IC50 of 0.6 micromol/L, failed to modify the infarct size limitation by preischemic infusion of bradykinin (% IS/AR = 11.7 +/- 3.4). Neither 5-HD nor HMR1098 alone modified infarct size (% IS/AR = 37.8 +/- 3.8 and 35.1 +/- 6.2, respectively). These results suggest that opening of the mito-K(ATP) channel but not the sarc-K(ATP) channel is involved in infarct size limitation by a mechanism triggered by bradykinin B2 receptor activation.
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PMID:Infarct size limitation by bradykinin receptor activation is mediated by the mitochondrial but not by the sarcolemmal K(ATP) channel. 1110 Nov 97

Sphingosine kinase phosphorylates sphingosine to generate sphingosine 1-phosphate, a phospholipid that has been implicated in signaling by a number of transmembrane receptors and was recently shown to act as a ligand for a specific class of G protein-coupled receptors. Here we show that the G protein-coupled bradykinin B2 receptor activates sphingosine kinase leading to a time- and dose-dependent elevation of cellular sphingosine 1-phosphate levels that was blocked by the sphingosine kinase inhibitor dihydrosphingosine. Furthermore, increasing doses of this inhibitor partially affected the bradykinin-mediated ERK/MAP kinase activation and fully blocked the protein kinase C-independent component of the signaling pathway from the B2 receptor to the ERK/MAP kinase cascade. Overexpression of sphingosine kinase did not additionally increase the bradykinin-induced ERK/MAP kinase activity, indicating a permissive rather than activating role of sphingosine 1-phosphate in B2 receptor-mediated mitogenic signaling.
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PMID:Activation of sphingosine kinase by the bradykinin B2 receptor and its implication in regulation of the ERK/MAP kinase pathway. 1125 64

Mitogenic signalling pathways from G protein-coupled receptors (GPCRs) to the mitogen-activated protein kinase (MAPK) cascade may involve alpha- or betagamma-subunits of heterotrimeric G proteins, receptor or non-receptor tyrosine kinases, adaptor molecules, phosphoinositide 3-kinases, protein kinase C, and probably other proteins. The majority of models describing the connection of different signalling proteins within a mitogenic pathway are based on experimental data obtained by co- and overexpression of epitope-tagged MAPK together with the respective GPCR and other signalling proteins of interest in transfectable cell lines. Here the link of the bradykinin B2 receptor (B2R) to MAPK in the COS-7 cell expression system is compared with mitogenic signalling pathways of bradykinin in various tumour cell lines. It becomes evident that in natural or tumour cells expressing individual amounts and different isoforms of signalling proteins completely other relations between B2R and MAPK may exist than in COS-7 cells, suggesting a high degree of cellular specificity in mitogenic signalling.
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PMID:Bradykinin signalling to MAP kinase: cell-specific connections versus principle mitogenic pathways. 1125 71

We used a cultured murine cell model of the inner medullary collecting duct (mIMCD-3 cells) to examine the regulation of the ubiquitous sodium-proton exchanger, Na+/H+ exchanger isoform 1 (NHE-1), by a prototypical G protein-coupled receptor, the bradykinin B2 receptor. Bradykinin rapidly activates NHE-1 in a concentration-dependent manner as assessed by proton microphysiometry of quiescent cells and by 2'-7'-bis[2-carboxymethyl]-5(6)-carboxyfluorescein fluorescence measuring the accelerated rate of pH(i) recovery from an imposed acid load. The activation of NHE-1 is blocked by inhibitors of the bradykinin B2 receptor, phospholipase C, Ca2+/calmodulin (CaM), and Janus kinase 2 (Jak2), but not by pertussis toxin or by inhibitors of protein kinase C and phosphatidylinositol 3'-kinase. Immunoprecipitation studies showed that bradykinin stimulates the assembly of a signal transduction complex that includes CaM, Jak2, and NHE-1. CaM appears to be a direct substrate for phosphorylation by Jak2 as measured by an in vitro kinase assay. We propose that Jak2 is a new indirect regulator of NHE-1 activity, which modulates the activity of NHE-1 by increasing the tyrosine phosphorylation of CaM and most likely by increasing the binding of CaM to NHE-1.
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PMID:Bradykinin B2 receptors activate Na+/H+ exchange in mIMCD-3 cells via Janus kinase 2 and Ca2+/calmodulin. 1127 60

Reversible phosphorylation plays important roles in G protein-coupled receptor signaling, desensitization, and endocytosis, yet the precise location and role of in vivo phosphorylation sites is unknown for most receptors. Using metabolic 32P labeling and phosphopeptide sequencing we provide a complete phosphorylation map of the human bradykinin B2 receptor in its native cellular environment. We identified three serine residues, Ser(339), Ser(346), and Ser(348), at the C-terminal tail as principal phosphorylation sites. Constitutive phosphorylation occurs at Ser(348), while ligand-induced phosphorylation is found at Ser(339) and Ser(346)/Ser(348) that could be executed by several G protein-coupled receptor kinases. In addition, we found a protein kinase C-dependent phosphorylation of Ser(346) that was mutually exclusive with the basal phosphorylation at Ser(348) and therefore may be implicated in differential regulation of B2 receptor activation. Functional analysis of receptor mutants revealed that a low phosphorylation stoichiometry is sufficient to initiate receptor sequestration while a clustered phosphorylation around Ser(346) is necessary for desensitization of the B2 receptor-induced phospholipase C activation. This was further supported by the specifically reduced Ser(346)/Ser(348) phosphorylation observed upon stimulation with a nondesensitizing B2 receptor agonist. The differential usage of clustered phosphoacceptor sites points to distinct roles of multiple kinases in controlling G protein-coupled receptor function.
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PMID:Determination of bradykinin B2 receptor in vivo phosphorylation sites and their role in receptor function. 1151 30

Bronchial vascular remodeling is an important feature of the pathology of chronic asthma, but the responsible mechanisms and main sources of angiogenic factors are unclear. Here we report that human airway smooth muscle cells express vascular endothelial growth factor (VEGF)121, 165, 189, 206 splice variants and secrete VEGF protein constitutively. VEGF protein secretion was increased by the proinflammatory asthma mediator bradykinin through post-transcriptional mechanisms. Bradykinin-induced VEGF secretion was dependent on the B2 bradykinin receptor, activation of protein kinase C, and generation of endogenous prostanoids. This is the first report that bradykinin can increase VEGF secretion in any biological system and the first to show that airway smooth muscle cells produce VEGF. Our results suggest a novel role for human airway smooth muscle in contributing to bronchial mucosal angiogenesis in chronic asthma by secretion of VEGF and suggest a wider role for mesenchymal cell products in mediating angiogenesis in inflammatory and allergic diseases.
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PMID:Human airway smooth muscle cells secrete vascular endothelial growth factor: up-regulation by bradykinin via a protein kinase C and prostanoid-dependent mechanism. 1168 73


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