Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

---

Query: EC:3.1.4.3 (phospholipase C)
18,461 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Aminoglycoside antibiotics (AGAs) are nephrotoxic, with most of the damage confined to the proximal tubule, but the mechanism for cellular toxicity is not clear. It has been previously shown that the extracellular-calcium sensing receptor (CaR) is expressed in intact rat proximal tubule and can be stimulated by the AGA neomycin. To investigate whether CaR could contribute to AGA-induced nephrotoxicity, the acute responses to various AGAs in the proximal tubule-derived opossum kidney (OK) cell line were examined. The presence in OK cells of CaR-related transcripts and protein was demonstrated by northern analyses, reverse transcriptase-PCR, immunocytochemistry, and immunoblotting. OK cells responded to elevated extracellular calcium (Ca(2+)(o)) and neomycin but also to gentamicin and tobramycin with an increase in cytosolic [Ca(2+)]. Ca(2+)(o), neomycin, and gentamicin also activated the extracellular signal-regulated kinases, ERK1 and ERK2. Neomycin-induced ERK activation was both dose- and time-dependent and was attenuated by inhibitors of phosphatidylinositol 3-kinase, phosphatidylinositol bisphosphate (PIP(2))-specific phospholipase C, and MEK1, but not of protein kinase C. Thus, proximal tubular OK cells express a CaR that mediates Ca(2+)(i) mobilization and PIP(2)-PLC-dependent ERK activation in response to AGAs and thus could play a role in AGA-induced nephrotoxicity.
...
PMID:Aminoglycosides increase intracellular calcium levels and ERK activity in proximal tubular OK cells expressing the extracellular calcium-sensing receptor. 1203 77

Membrane-mediated increases in protein kinase C (PKC) activity and PKC-dependent physiological responses of growth plate chondrocytes to vitamin D metabolites depend on the state of endochondral maturation; 1alpha,25-dihydroxyvitamin D(3) [1alpha,25-(OH)(2)D(3)] regulates growth zone (GC) cells, whereas 24R,25-(OH)(2)D(3) regulates resting zone (RC) cells. Different mechanisms, including protein kinase A signaling, mediate the effects of 1alpha,25-(OH)(2)D(3) and 24R,25-(OH)(2)D(3) on PKC, suggesting that different mechanisms may also regulate any MAPK involvement in the physiological responses. This study used confluent cultures of rat costochondral chondrocytes as a model. 1alpha,25-(OH)(2)D(3) stimulated MAPK specific activity in GC in a time- and dose-dependent manner, evident within 9 min. 24R,25-(OH)(2)D(3) stimulated MAPK in RC; increases were dose dependent, occurred after 9 min, and were greatest at 90 min. In both cells the effect was due to ERK1/2 activation (p42 > p44 in GC; p42 = p44 in RC). MAPK activation was dependent on PKC, but not protein kinase A. The effect of 1alpha,25-(OH)(2)D(3) required phospholipase C, and the effect of 24R,25-(OH)(2)D(3) required phospholipase D. Inhibition of cyclooxygenase activity reduced the effect of 1alpha,25-(OH)(2)D(3) on MAPK in GC and enhanced the effect of 24R,25-(OH)(2)D(3) in RC. Based on MAPK inhibition with PD98059, ERK1/2 MAPK mediated the effect of 24R,25-(OH)(2)D(3) on [(3)H]thymidine incorporation and [(35)S]sulfate incorporation by RC, but only partially mediated the effect of 1alpha,25-(OH)(2)D(3) on GC. ERK1/2 was not involved in the regulation of alkaline phosphatase specific activity by either metabolite. This paper supports the hypothesis that 1alpha,25-(OH)(2)D(3) regulates the physiology of GC via rapid membrane-mediated signaling pathways, and some, but not all, of the response to 1alpha,25-(OH)(2)D(3) is via the ERK family of MAPKs. In contrast, 24R,25-(OH)(2)D(3) exerts its effects on RC via PKC-dependent MAPK. Whereas 1alpha,25-(OH)(2)D(3) increases MAPK activity via phospholipase C and increased prostaglandin production, 24R,25-(OH)(2)D(3) increases MAPK via phospholipase D and decreased prostaglandin production. The cell specificity, metabolite stereospecificity, and the dependence on PKC argue for the participation of membrane receptors for 1alpha,25-(OH)(2)D(3) and 24R,25-(OH)(2)D(3) in the regulation of ERK1/2 in the growth plate.
...
PMID:1alpha,25-dihydroxyvitamin D(3) and 24R,25-dihydroxyvitamin D(3) modulate growth plate chondrocyte physiology via protein kinase C-dependent phosphorylation of extracellular signal-regulated kinase 1/2 mitogen-activated protein kinase. 1207 13

The signalling pathways by which muscarine and epidermal growth factor (EGF) regulate the secretion of the alpha-secretase cleavage product (sAPPalpha) of the amyloid precursor protein (APP) were examined in the human neuroblastoma SH-SY5Y. Using specific inhibitors it was found that over 80% of sAPPalpha secretion, enhanced by muscarine, occurred via the extracellular signal-regulated kinase (ERK1/2) member of the mitogen-activated protein kinase (MAPK) family and was dependent on protein kinase Calpha (PKCalpha) and a member of the Src family of non-receptor tyrosine kinases (Src-TK). In contrast the stimulation of sAPPalpha secretion by EGF was not affected by inhibitors of PKC nor Src-TK but was dependent on ERK1/2. In addition muscarine-enhanced sAPPalpha secretion and ERK1/2 activation were inhibited 60 and 80%, respectively, by micromolar concentrations of the phosphatidylinositol 3 kinase (PI-3K) inhibitor wortmannin. In comparison wortmannin decreased EGF stimulation of sAPPalpha secretion and ERK 1/2 activation by approximately 40%. Unexpectedly, U73122, an inhibitor of phosphoinositide-specific phospholipase C, did not inhibit muscarine enhancement of sAPPalpha secretion. These data are discussed in relation to a pathway for the enhancement of sAPPalpha secretion by muscarine which involves the activation of a Src-TK by G-protein beta/gamma-subunits leading to activation of PKCalpha, and ERK1/2 by a mechanism not involving phospholipase C.
...
PMID:Muscarine enhances soluble amyloid precursor protein secretion in human neuroblastoma SH-SY5Y by a pathway dependent on protein kinase C(alpha), src-tyrosine kinase and extracellular signal-regulated kinase but not phospholipase C. 1219 95

Serotonin (5-hydroxytryptamine; 5-HT), acting via the 5-HT(2A) receptor, up-regulates the transcription and production of interstitial collagenase (matrix metalloproteinase-13; MMP-13), a critical enzyme responsible for maintaining the integrity of the uterus, after parturition. Serotonin treatment of rat uterine myometrial smooth muscle cells induced inositol phosphate (IP) turnover, which was abolished by the 5-HT(2A) receptor-specific antagonists ketanserin and spiperone. The phospholipase C (PLC) inhibitors and D609 attenuated serotonin-mediated-IP turnover with a corresponding inhibition of MMP-13 protein production. Subsequent recovery of both MMP-13 protein expression and IP generation was seen following the removal of D609. Protein kinase C (PKC) activators, the diacylglycerol analogue 1,2-dioctanoyl-sn-glycerol and phorbol myristate acetate (PMA), mimicked the effect of serotonin on MMP-13 protein expression; prolonged PMA treatment (which down-regulates PKC) lowered MMP-13 protein levels. The PKC-specific inhibitors bisindolylmaleimide I, calphostin C, CGP 41251, and the PKCdelta-selective inhibitor rottlerin were able to suppress serotonin up-regulation of MMP-13. Furthermore, the mitogen-activated protein kinase kinase (MEK) inhibitor PD98059 blocked serotonin-dependent activation of p44/42 MAPK (pERK1/2), a downstream effector of PKC and also down-regulated MMP-13 protein expression. Similarly, calphostin C and rottlerin depressed activation of p44/42 MAPK. From these studies, serotonin, binding through the 5-HT(2A) receptor, initiates a signaling cascade whereby stimulation of PLC leads to the activation of PKC and subsequently the ERK1/2 pathway, which ultimately results in MMP-13 production.
...
PMID:Serotonin-induced MMP-13 production is mediated via phospholipase C, protein kinase C, and ERK1/2 in rat uterine smooth muscle cells. 1221 12

The group I metabotropic glutamate receptors (mGluRs) are positively coupled to phospholipase C. Through phospholipase C, group I mGluR activation increases intracellular concentrations of diacylglycerol which is known as a strong activator of protein kinase C (PKC). This study investigated the putative role of PKC in the regulation of transcription factor phosphorylation induced by group I mGluR activation in the rat striatum in vivo. We found that the group I agonist 3,5-dihydroxyphenylglycine (DHPG) injected into the dorsal striatum (caudate-putamen) increased phosphorylation of the two transcription factors, cAMP response element-binding protein (CREB) and Elk-1, and extracellular signal-regulated kinase 1/2 (ERK1/2) in the injected striatum. Inhibition of PKC with GF109203X significantly attenuated DHPG-stimulated CREB, Elk-1, and ERK1/2 phosphorylation. Activation of PKC with intracaudate injection of 12-O-tetradecanoylphorbol-13-acetate (TPA) mimicked DHPG actions in facilitating the phosphorylation of CREB, Elk-1, and ERK1/2. Blockade of N-methyl-D-aspartate (NMDA) glutamate receptors with the non-competitive antagonist MK801 or the competitive antagonist AP5 attenuated TPA-induced CREB, Elk-1, and ERK1/2 phosphorylation. Similarly, inhibition of Ca(2+)/calmodulin-dependent protein kinases (CaMK) with KN62 also resulted in a significant attenuation of TPA induction of the three phosphoproteins. The data obtained from this study indicate that selective activation of PKC is needed for the group I agonist-induced CREB, Elk-1, and ERK1/2 phosphorylation in striatal neurons. Activated PKC may, at least in part, facilitate the phosphorylation of transcription factors via an NMDA/CaMK-sensitive pathway.
...
PMID:Regulation of transcription factor phosphorylation by metabotropic glutamate receptor-associated signaling pathways in rat striatal neurons. 1222 May 59

alpha(1a)-Adrenergic receptors (ARs) couple to phosphoinositide hydrolysis, adenylyl cyclase, and mitogen-activated protein kinase (MAPK) pathways. However, the interaction among these signaling pathways in activating extracellular signal-regulated kinase 1/2 (ERK1/2) is not well understood. We investigated the coupling of alpha(1a)-ARs to ERK1/2 in Chinese hamster ovary (CHO)-K1 cells stably transfected with mouse alpha(1a)-ARs, as well as the interaction between ERK1/2 and norepinephrine-induced cAMP accumulation. alpha(1a)-AR activation by norepinephrine increased the cytosolic Ca(2+) concentration and phosphorylated ERK1/2 in a time- and concentration-dependent manner. ERK1/2 phosphorylation was blocked by the MAPK kinase 1/2 inhibitor 2'-amino-3'-methoxyflavone (PD 98059) and the alpha(1)-AR antagonist prazosin. A transient elevation in intracellular Ca(2+) was required for the phosphorylation of ERK1/2; however, activation of protein kinase C did not seem to be required for ERK1/2 phosphorylation. Norepinephrine also stimulated cAMP accumulation in transfected CHO-K1 cells in a concentration-dependent manner via alpha(1a)-ARs, which was blocked by the Ca(2+) chelator 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid. Norepinephrine-induced ERK1/2 phosphorylation was inhibited by the adenylyl cyclase activator forskolin and was enhanced by the adenylyl cyclase inhibitor 9-(tetrahydro-2-furanyl)-9H-purine-6-amine (SQ 22536) and the protein kinase A inhibitor 4-cyano-3-methylisoquinoline. In conclusion, in transfected CHO-K1 cells, alpha(1a)-AR activation activates both phospholipase C and adenylyl cyclase-mediated signaling pathways. alpha(1a)-AR-mediated ERK1/2 phosphorylation was dependent on a rise in intracellular Ca(2+), and this pathway was reciprocally regulated by the concomitant activation of adenylyl cyclase, which inhibits ERK1/2 phosphorylation. Thus, alpha(1a)-AR stimulation of cAMP production may play an important role in regulating ERK1/2 phosphorylation in cell lines and native tissues.
...
PMID:Tonic inhibitory role for cAMP in alpha(1a)-adrenergic receptor coupling to extracellular signal-regulated kinases 1/2. 1223 58

Nicotine is not only a major component in tobacco but is also a survival agonist that inhibits apoptosis induced by diverse stimuli including chemotherapeutic drugs. However, the intracellular mechanism(s) involved in nicotine suppression of apoptosis is unclear. Bcl2 is a potent antiapoptotic protein and tumor promotor that is expressed in both small cell lung cancer (SCLC) and non-small cell lung cancer (NSCLC) cells. It is possible that nicotine may regulate Bcl2 to stimulate cell survival. Here we report that nicotine can induce Bcl2 phosphorylation exclusively at the serine 70 site in association with prolonged survival of SCLC H82 cells expressing wild-type but not the phosphorylation-deficient S70A mutant Bcl2 after treatment with chemotherapeutic agents (i.e. cisplatin or VP-16). Nicotine induces activation of PKC alpha and the MAPKs ERK1 and ERK2, which are physiological Bcl2 kinases. Furthermore, ET-18-OCH3, a specific phospholipase C (PLC) inhibitor, blocks nicotine-stimulated Bcl2 phosphorylation and promotes apoptosis, suggesting that PLC may be involved in nicotine activation of Bcl2 kinases. Using a genetic approach, the gain-of-function S70E mutant, which mimics Ser(70) site phosphorylation in the flexible loop domain, potently enhances chemoresistance in SCLC cells. Thus, nicotine-induced cell survival results, at least in part, from a mechanism that involves Bcl2 phosphorylation. Therefore, novel therapeutic strategies for lung cancer in which Bcl2 is expressed may be used to abrogate the anti-apoptotic activity of Bcl2 by inhibiting multiple upstream nicotine-activated pathways.
...
PMID:A functional role for nicotine in Bcl2 phosphorylation and suppression of apoptosis. 1242 19

Diacylglycerol (DAG) and ceramide are important second messengers affecting cell growth, differentiation, and apoptosis. Balb/c-3T3 fibroblast cells expressing dopamine-D2S (short) receptors (Balb-D2S cells) provide a model of G protein-mediated cell growth and transformation. In Balb-D2S cells, apomorphine (EC(50) = 10 nM) stimulated DAG and ceramide formation by 5.6- and 4.3-fold, respectively, maximal at 1 h and persisting over 6 h. These actions were blocked by pretreatment with pertussis toxin (PTX), implicating G(i)/G(o) proteins. To address which G proteins are involved, Balb-D2S clones expressing individual PTX-insensitive Galpha(i) proteins were treated with PTX and tested for apomorphine-induced responses. Neither PTX-insensitive Galpha(i2) nor Galpha(i3) rescued D2S-induced DAG or ceramide formation. Both D2S-induced DAG and ceramide signals required Gbetagamma-subunits and were blocked by inhibitors of phospholipase C [1-(6-[([17beta]-3-methoxyestra-1,2,3[10]-trien- 17yl)amino]hexyl)-1H-pyrrole-2,5-dione (U-73122) and partially by D609]. The similar G protein specificity of D2S-induced calcium mobilization, DAG, and ceramide formation indicates a common Gbetagamma-dependent phospholipase C-mediated pathway. Both D2 agonists and ceramide specifically induced mitogen-activated protein kinase (ERK1/2), suggesting that ceramide mediates a novel pathway of D2S-induced ERK1/2 activation, leading to cell growth.
...
PMID:Diacylglycerol and ceramide formation induced by dopamine D2S receptors via Gbeta gamma -subunits in Balb/c-3T3 cells. 1243 10

The small GTPases Ras or Rap1 were suggested to mediate the stimulatory effect of some G protein-coupled receptors on ERK activity in neuronal cells. Accordingly, we reported here that pituitary adenylate cyclase-activating polypeptide (PACAP), whose G protein-coupled receptor triggers neuronal differentiation of the PC12 cell line via ERK1/2 activation, transiently activated Ras and induced the sustained GTP loading of Rap1. Ras mediated peak stimulation of ERK by PACAP, whereas Rap1 was necessary for the sustained activation phase. However, PACAP-induced GTP-loading of Rap1 was not sufficient to account for ERK activation by PACAP because 1) PACAP-elicited Rap1 GTP-loading depended only on phospholipase C, whereas maximal stimulation of ERK by PACAP also required the activity of protein kinase A (PKA), protein kinase C (PKC), and calcium-dependent signaling; and 2) constitutively active mutants of Rap1, Rap1A-V12, and Rap1B-V12 only minimally stimulated the ERK pathway compared with Ras-V12. The effect of Rap1A-V12 was dramatically potentiated by the concurrent activation of PKC, the cAMP pathway, and Ras, and this potentiation was blocked by dominant-negative mutants of Ras and Raf. Thus, this set of data indicated that GPCR-elicited GTP loading of Rap1 was not sufficient to stimulate efficiently ERK in PC12 cells and required the permissive co-stimulation of PKA, PKC, or Ras.
...
PMID:Stimulation of the ERK pathway by GTP-loaded Rap1 requires the concomitant activation of Ras, protein kinase C, and protein kinase A in neuronal cells. 1247 65

Urotensin-II (U-II), a vasoactive cyclic neuropeptide, was recently identified as the natural ligand for the G-protein coupled receptor GPR14. The expression pattern of U-II and GPR14 are consistent with a role as a neurohormonal regulatory system in cardiovascular homeostasis. Urotensin-II induces a rapid and short-lasting rise in intracellular calcium in recombinant GPR14 expressing cells. In the present study we show that U-II induces signal transduction pathways leading to the long-lasting activation of extracellular signal-regulated kinase 1/2 (ERK1/2) in chinese hamster ovary cells expressing human GPR14 (CHO-GPR14). Furthermore, we observed a growth-stimulating and PD98059 sensitive activity of U-II in CHO-GPR14 cells, but not CHO-K1 cells. The investigation of the GPR14 induced signal transduction pathways leading to ERKI/2 phosphorylation revealed a previously unsuspected role for G(i/o)-protein coupling and showed an involvement of phospatidylinositol-3-kinase, phospholipase C and calcium channel mediated mechanisms. Our results suggest that U-II and its receptor GPR14 may be involved in long-lasting physiological effects such as cardiovascular remodeling.
...
PMID:Urotensin II mediates ERK1/2 phosphorylation and proliferation in GPR14-transfected cell lines. 1250 13


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>

---