Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P51812 (mitogen-activated protein)
 10,636 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The response of rat hepatocytes to hormones and growth factors has been extensively studied with respect to phospholipase regulation and calcium mobilization. However, the mitogen-activated protein (MAP) kinase cascade which integrates signals from a wide variety of extracellular stimuli has not been examined in these cells. Thus, in the present study the pathways leading to activation of MAP kinase in primary cultures of adult rat hepatocytes were investigated. Growth factors acting through tyrosine kinase receptors (epidermal growth factor and hepatocyte growth factor) increased Raf and MAP kinase activity through a protein kinase C and calcium-independent pathway. Agonists acting through seven-membrane-spanning receptors (arginine vasopressin and angiotensin II) increased intracellular calcium concentration but did not stimulate Raf or MAP kinase activity. Arginine vasopressin, however, stimulated MAP kinase activity in rat 1a fibroblasts transfected with the hepatic V1a receptor and in rat aortic vascular smooth muscle cells. Phorbol 12-myristate 13-acetate (PMA) was also unable to stimulate Raf and MAP kinase in hepatocytes in spite of a marked activation of protein kinase C. We conclude that only signals arising from tyrosine kinase receptors are able to activate MAP kinase in hepatocytes. Neither agonists acting through seven-membrane-spanning receptors nor phorbol esters stimulate MAP kinase in hepatocytes. The results suggest that specific cellular components that link seven-membrane-spanning receptors with MAP kinase activation in tissues such as vascular smooth muscle are absent in rat hepatocytes.
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PMID:Tyrosine kinase growth factor receptors but not seven-membrane-spanning receptors or phorbol esters activate mitogen-activated protein kinase in rat hepatocytes. 755 84

The present study was undertaken to determine whether an inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A (HMG CoA) reductase, simvastatin, modulates the cellular action of arginine vasopressin (AVP) in the cultured rat glomerular mesangial cells. AVP increases cellular free calcium ([Ca2+]i) in a dose-dependent manner. The 1 x 10(-7) M AVP-mobilized [Ca2+]i was significantly reduced in the cells pretreated with 1 x 10(-6) M simvastatin. AVP produced a biphasic change in cellular pH, namely, an early acidification followed by a sustained alkalinization, and the AVP-induced cellular alkalinization disappeared after exposing to simvastatin. 1 x 10(-7) M AVP activated mitogen-activated protein (MAP) kinase from 15.5-30.4 pmol/mg protein, an effect significantly less in the presence of simvastatin. Also, 1 x 10(-7) M AVP significantly increased [3H]thymidine incorporation by 1.6-fold, and its incorporation was totally diminished in cells pretreated with simvastatin. The AVP-induced [Ca2+]i mobilization and MAP kinase activation were totally restored when cells were preexposed to a mixture of mevalonate and simvastatin. [3H]AVP receptor binding was not affected by the simvastatin treatment. 1 x 10(-7) AVP increased inositol trisphosphate production by 1.8-fold, which was significantly reduced by the presence of simvastatin. These results may indicate that nonsterol pathway plays a crucial role in the cellular action of AVP to produce cell growth of glomerular mesangium.
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PMID:Simvastatin inhibits the cellular signaling and proliferative action of arginine vasopressin in cultured rat glomerular mesangial cells. 772 Jun 43

Endothelins are paracrine or autocrine peptides that regulate diverse aspects of renal function. In addition to their potent vasoconstrictor activity, recent evidence suggests that endothelin-1 is a growth factor for renal cells. Different forms of renal injury markedly upregulate endothelin-1 secretion, which is postulated to contribute to compensatory renal growth. Similar roles have been hypothesized for other vasoactive peptides, such as angiotensin II and arginine vasopressin. New information has recently emerged regarding pathways of mitogenic signaling linking activation of endothelin receptors to changes in gene expression. ETA receptor subtypes activate downstream effectors, such as protein kinase C, protein tyrosine kinases of the src gene family, and mitogen-activated protein kinases. These cytosolic effectors in turn lead to altered programs of gene expression by activating, among others, AP-1 and serum response factor transcription factors. In addition, recent studies in organisms amenable to genetic analysis, such as Drosophila, Dictyostelium, and yeast, are providing important clues to effector mechanisms employed by vasoactive peptide receptors in higher organisms. Information on the molecular mechanisms for mitogenic signaling by endothelin receptors might be used to gain insight into the pathogenesis of compensatory renal growth and the development of novel therapeutic strategies.
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PMID:Endothelin peptides and compensatory growth of renal cells. 785 Apr 15

The preincubation of vascular smooth muscle cells (VSMC) with a non-peptide arginine vasopressin (AVP) antagonist (OPC-21268) (0.5 mM) for 10 min completely inhibited the 1 microM AVP-induced activation of mitogen-activated protein (MAP) kinase but did not affect the angiotensin II-, protein kinase C activator- or ionomycin-stimulated MAP kinase. Similar results were obtained with the simultaneous administration of AVP and OPC-21268. This inhibitory effect of OPC-21268 completely disappeared after washing the cells pretreated with OPC-21268. In contrast, the preincubation of VSMC with a peptide AVP antagonist, d(CH2)5Tyr(Me)AVP (1 microM), for 10 min completely blocked the 1 microM AVP-activated MAP kinase but the simultaneous administration of d(CH2)5Tyr(Me)AVP with AVP could inhibit that only by 40%. However, the washing procedure did not affect the inhibitory effect of d(CH2)5Tyr(Me)AVP. These results indicate that OPC-21268 is a specific AVP antagonist to inhibit the AVP-induced activation of MAP kinase. The antagonistic effect of OPC-21268 is also suggested to be relatively weak but prompt as compared to that of a peptide AVP antagonist d(CH2)5Tyr(Me)AVP.
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PMID:Distinct inhibition by non-peptide and peptide arginine vasopressin antagonists of vasopressin-induced activation of mitogen-activated protein kinase in cultured rat vascular smooth muscle cells. 817 97

Studies have suggested that endothelin-1 (ET-1) activates cellular contraction and proliferation in rat vascular smooth muscle cells (VSMC). We examined whether an ET(A) receptor antagonist, BQ-123, inhibits the following cellular actions of ET-1 in rat VSMC: cytosolic free calcium ([Ca2+]i) mobilization, cellular contraction, mitogen-activated protein (MAP) kinase activation, [3H]thymidine incorporation, and MTT reduction. [Ca2+]i was measured by the fluorescent method. MAP kinase activity was measured by the phosphorylation of a synthetic peptide of a specific substrate for MAP kinase. The specificity of BQ-123 for ET-1-activated MAP kinase was checked by Western blotting analysis. [3H]thymidine incorporation and MTT reduction studies were performed using the cells incubated for 12 h with serum-free medium containing effectors. BQ-123 inhibited ET-1 receptor binding and blocked [Ca2+]i mobilization, cellular contraction, MAP kinase activation, [3H]thymidine incorporation, and MTT reduction in response to ET-1. BQ-123 did not affect the arginine vasopressin (AVP)- and angiotensin II (Ang II)-induced increases in [Ca2+]i mobilization or in MAP kinase activity. Preincubation with BQ-123 did not enhance its inhibitory effects but these effects of BQ-123 were diminished by washing after preincubation. Receptor studies revealed that the washing procedure decreased the inhibitory effect of BQ-123 on ET-1 binding to receptors. These results indicate that BQ-123 is a potent and specific ET(A) receptor antagonist that blocks the ET-1-induced cellular contraction and proliferation in rat VSMC.
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PMID:Inhibitory effect of BQ-123 on endothelin-1-stimulated mitogen-activated protein kinase and cell growth of rat vascular smooth muscle cells. 882 20

The present study was undertaken to determine whether low density lipoprotein (LDL) modulates the cellular action of arginine vasopressin (AVP) in cultured glomerular mesangial cells of spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto rats (WKY). The AVP-induced cellular signal transduction, including inositol 1,4,5-trisphosphate (IP3) production, fura-2 intracellular calcium measurements and cellular alkalinization, was significantly greater in cells of SHR than those of WKY. This is based on an increase in AVP V1 receptor number in cells of the SHR. Also, the AVP activation of mitogen-activated protein (MAP) kinase and [3H]thymidine incorporation was significantly exaggerated in cells of SHR compared with those of WKY. LDL at a concentration of 10 micrograms/ml augmented the cellular signaling and proliferative action of AVP in cells of WKY, but not in those of SHR. Since [3H]AVP receptor binding was not affected by the LDL pretreatment, LDL modulates the signal transduction between a location distal to the AVP receptors and proximal from the production of IP3 and diacylglycerol. These results indicate that an increase in AVP receptor capacity has a profound effect on the AVP-induced cellular signaling and proliferation, and that LDL has a slight alteration on the action of AVP in glomerular mesangial cells of SHR.
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PMID:Cellular signaling and proliferative action of AVP in mesangium of SHR: effect of low density lipoprotein. 891 16

The present study was undertaken to determine whether phospholipase D participates in the mitogenic action of arginine vasopressin (AVP) in cultured rat glomerular mesangial cells. AVP promptly increased the phosphatidylethanol formation in a concentration-dependent manner, which indicates the activation of phospholipase D. When cells were preincubated with 2,3-diphosphoglycerate or carbobenzyloxy-leucine-tyrosine-chloromethylketone (zLYCK), inhibitors of phospholipase D, the 1 x 10(-7) M AVP-produced phosphatidylethanol was significantly attenuated. Also, inhibitors of protein kinase C, staurosporine and calphostin C, reduced the AVP-induced increase in phosphatidylethanol. AVP activated mitogen-activated protein (MAP) kinase in a concentration-dependent manner. Such an activation was significantly reduced by 2,3-diphosphoglycerate, zLYCK, or staurosporine. Also, AVP stimulated [3H]thymidine incorporation, an effect significantly less in the presence of 2,3-diphosphoglycerate or zLYCK. Similar results were obtained with exogenous bacterial phospholipase D. Both MAP kinase and [3H]thymidine incorporation were not altered by 2,3-diphosphoglycerate or zLYCK per se. These results indicate that AVP activates phospholipase D and promotes cellular growth mediated through phospholipase D, in addition to a phospholipase C-dependent signal transduction, in glomerular mesangial cells.
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PMID:The activation of phospholipase D participates in the mitogenic action of arginine vasopressin in cultured rat glomerular mesangial cells. 894 Mar 66

The present study was undertaken to determine whether extracellular adenosine 5'-triphosphate (ATP) promotes cellular proliferation of cultured rat renal inner medullary collecting duct cells. Extracellular ATP increased inositol 1,4,5-triphosphate (IP3) production and cellular free calcium concentration - [Ca2+]i - in a dose-dependent manner. ATP also caused a transient cellular acidification. Extracellular ATP activated mitogen-activated protein (MAP) kinase and [3H]thymidine incorporation in a dose-dependent manner. However, such effects were not obtained with adenosine 5'-diphosphate, adenosine monophosphate, and adenosine. In addition, uridine triphosphate, a P(2u) purinergic agonist, increased IP3 production and activated MAP kinase. 2-Methylthio ATP, a P(2y) purinergic agonist, also increased IP3 production, but did not affect the MAP kinase activity. We also examined the effect of arginine vasopressin on cellular growth. Arginine vasopressin did not alter MAP kinase activity and [3H]thymidine incorporation in cultured rat renal inner medullary collecting duct cells. These results indicate that extracellular ATP activates phospholipase C mediated through P(2u) and P(2y) purinergic receptors and promotes cellular proliferation mediated through P(2u) purinergic receptors in renal inner medullary collecting duct cells.
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PMID:Extracellular ATP promotes cellular growth of renal inner medullary collecting duct cells mediated via P2u receptors. 920 Apr 13

The present study was undertaken to determine whether transforming growth factor (TGF)-beta1 modulates the cellular actions of arginine vasopressin (AVP) in cultured rat glomerular mesangial cells. AVP increased cytosolic free calcium ([Ca2+]i), and TGF-beta1 dose-dependently reduced the AVP-mobilized [Ca2+]i. Such an inhibition by exogenous TGF-beta1 was abolished by liposomal transfection of antisense oligodeoxynucleotide for the TGF-beta type II receptor. AVP activated mitogen-activated protein (MAP) kinase, which was significantly reduced by 1 ng/ml TGF-beta1. AVP increased [3H]thymidine incorporation into mesangial cells in a dose-dependent manner, and 1 ng/ml TGF-beta1 significantly reduced the AVP-stimulated [3H]thymidine incorporation. However, 10 microM antisense oligodeoxynucleotide for the TGF-beta type II receptor seemed to attenuate the inhibition by TGF-beta1. 1 X 10(-7) M AVP significantly increased inositol 1,4,5-trisphosphate (IP3) production by 1.8-fold, but this production was totally blunted by 1 ng/ml TGF-beta1. TGF-beta1 did not affect [3H]AVP receptor binding. 1 X 10(-6) M AVP concentration stimulated TGF-beta1 production in mesangial cells by 4-fold. These results indicate that TGF-beta1 inhibits the cellular signaling of AVP at steps beyond the AVP receptors and prior to the phospholipase C activation, and that TGF-beta1 may participate in a negative feedback regulation on the cellular action of AVP in glomerular mesangial cells.
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PMID:Inhibition by transforming growth factor-beta1 of the cellular action of arginine vasopressin in cultured rat glomerular mesangial cells. 1051 39

We previously showed that arginine vasopressin (AVP) stimulates heat shock protein 27 (HSP27) induction through protein kinase C activation in aortic smooth muscle A10 cells. In the present study, we examined whether the mitogen-activated protein (MAP) kinase superfamily is involved in the AVP-stimulated HSP27 induction in A10 cells. AVP stimulated the phosphorylation of p42/p44 MAP kinase and p38 MAP kinase. On the contrary, AVP had little effect on SAPK (stress-activated protein kinase)/JNK (c-Jun N-terminal kinase) phosphorylation. The HSP27 accumulation by AVP was not affected by PD98059, an inhibitor of the upstream kinase that activates p42/p44 MAP kinase. SB203580 and PD169316, specific inhibitors of p38 MAP kinase, suppressed the AVP-induced accumulation of HSP27. 12-O-tetradecanoylphorbol 13-acetate, an activator of protein kinase C, induced accumulation of HSP27 and was not inhibited by PD98059 but was inhibited by SB203580. Calphostin C and ET-18-OCH(3), inhibitors of protein kinase C, reduced the phosphorylation of p38 MAP kinase by AVP. SB203580 and PD169316 suppressed the AVP-increased levels in mRNA for HSP27. Dissociation of the aggregated HSP27 to the dissociated HSP27 was induced by AVP. These results strongly suggest that p38 MAP kinase takes part in the pathway of the AVP-stimulated induction of HSP27 in vascular smooth muscle cells.
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PMID:p38 MAP kinase is required for vasopressin-stimulated HSP27 induction in aortic smooth muscle cells. 1067 16


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