scholarly journals Endothelin stimulates mitogen-activated protein kinase activity in mesangial cells through ETA.

1994 ◽  
Vol 5 (4) ◽  
pp. 1074-1080
Author(s):  
Y Wang ◽  
J Pouysségur ◽  
M J Dunn

Accumulating evidence suggests that endothelin (ET) contributes to the pathophysiology of such disorders as acute renal failure, cyclosporine-mediated renal and vascular toxicity, and perhaps even glomerular inflammation. The postreceptor signaling pathways that mediate the actions of ET in these pathophysiologic conditions may include activation of kinase cascades. Thus, the effects of ET isopeptides on p42 and p44 mitogen-activated protein (MAP) kinase activity in rat glomerular mesangial cells were examined. ET-1 activated both p42 and p44 MAP kinases with similar dose responses and different kinetics. The threshold for kinase activation was 10(-9) M ET-1. ET-1 stimulated p42 and p44 MAP kinases with similar rapid (5 min) but different sustained activation of p42 (3 to 6 h) and p44 (1 to 2 h). Endothelin-3 (ET-3) also activated both isoforms of MAP kinase but with a threshold at 10(-7) M. Compared with ET-1, ET-3 stimulated only a rapid increase of p42 MAP kinase activity. We further investigated which ET receptors are coupled to MAP kinase activation. BQ-123, an ETA blocker, completely blocked the responsiveness of the MAP kinase to either ET-1 or ET-3. In Chinese hamster lung fibroblasts transfected with ETA or ETB cDNA, both receptors showed a rapid stimulation of MAP kinase in response to ET-1. These results suggest that ET can activate MAP kinases through both ET receptors but act exclusively through ETA in glomerular mesangial cells.

1999 ◽  
Vol 277 (2) ◽  
pp. L282-L291 ◽  
Author(s):  
Sheu-Ling Lee ◽  
Wei-Wei Wang ◽  
Geraldine A. Finlay ◽  
Barry L. Fanburg

Our previous studies have shown that, through an active transport process, serotonin (5-HT) rapidly elevates[Formula: see text] formation, stimulates protein phosphorylation, and enhances proliferation of bovine pulmonary artery smooth muscle cells (SMCs). We presently show that 1 μM 5-HT also rapidly elevates phosphorylation and activation of the mitogen-activated protein (MAP) kinases extracellular signal-regulated kinase (ERK) 1 and ERK2 of SMCs, and the enhanced phosphorylation is blocked by the antioxidants Tiron, N-acetyl-l-cysteine (NAC), and Ginkgo biloba extract. Inhibition of MAP kinase with PD-98059 failed to block enhanced[Formula: see text] formation by 5-HT. Chinese hamster lung fibroblasts (CCL-39 cells), which demonstrate both 5-HT transporter and receptor activity, showed a similar response to 5-HT (i.e., enhanced mitogenesis, [Formula: see text]formation, and ERK1 and ERK2 phosphorylation and activation). Unlike SMCs, they also responded to 5-HT receptor agonists. We conclude that downstream signaling of MAP kinase is a generalized cellular response to 5-HT that occurs secondary to[Formula: see text] formation and may be initiated by either the 5-HT transporter or receptor depending on the cell type.


Zygote ◽  
1996 ◽  
Vol 4 (3) ◽  
pp. 191-198 ◽  
Author(s):  
Maki Inoue ◽  
Kunihiko Naito ◽  
Taisuke Nakayama ◽  
Eimei Sato

SummaryPreviously we have shown that mitogen-activated protein (MAP) kinase activity abruptly increases at the first metaphase (M1) and remains significantly higher than that at the germinal vesicle (GV) stage until the second metaphase (M2) in porcine oocytes cultured in vitro. The present paper describes how the mechanism of the blockage of meiotic maturation by protein sythesis inhibition involves MAP kinase regulation. Cycloheximide arrested both germinal vesicle breakdown (GVBD) and the normal transition from M1 to M2. MAP kinase activation was also reduced in these maturation-inhibited oocytes. By using immunofluorescence microscopy with the monoclonal antibody raised against rat α-tubulin, we showed that cycloheximide caused morphological abnormality in a spindle at M1, but not at M2. All these results indicate that in porcine oocytes: (1) GV blockage by protein synthesis inhibition involves the suppression of both histone H1 kinase and MAP kinase activation, (2) during the transition from M1 to M2, maintenance of a normal metaphasic spindle and high MAP kinase activity require protein synthesis, and (3) once the M2 cytoskeletal structures have been completed, and/or after the ‘critical period’, cytostatic factor activity is independent of protein synthesis.


1999 ◽  
Vol 277 (3) ◽  
pp. F328-F337 ◽  
Author(s):  
Babu V. Bassa ◽  
Daeyoung D. Roh ◽  
Nosratola D. Vaziri ◽  
Michael A. Kirschenbaum ◽  
Vaijinath S. Kamanna

Although lysophosphatidylcholine (LPC)-mediated cellular responses are attributed to the activation of protein kinase C (PKC), relatively little is known about the upstream signaling mechanisms that regulate the activation of PKC and downstream mitogen-activated protein (MAP) kinase. LPC activated p42 MAP kinase and PKC in mesangial cells. LPC-mediated MAP kinase activation was inhibited (but not completely) by PKC inhibition, suggesting additional signaling events. LPC stimulated protein tyrosine kinase (PTK) activity and induced Ras-GTP binding. LPC-induced MAP kinase activity was blocked by the PTK inhibitor genistein. Because LPC increased PTK activity, we examined the involvement of phospholipase Cγ-1 (PLCγ-1) as a key participant in LPC-induced PKC activation. LPC stimulated the phosphorylation of PLCγ-1. PTK inhibitors suppressed LPC-induced PKC activity, whereas the same had no effect on phorbol 12-myristate 13-acetate-mediated PKC activity. Other lysophospholipids [e.g., lysophosphatidylinositol and lysophosphatidic acid (LPA)] also induced MAP kinase activity, and only LPA-induced MAP kinase activation was sensitive to pertussis toxin. These results indicate that LPC-mediated PKC activation may be regulated by PTK-dependent activation of PLCγ-1, and both PKC and PTK-Ras pathways are involved in LPC-mediated downstream MAP kinase activation.


2002 ◽  
Vol 103 (s2002) ◽  
pp. 132S-136S ◽  
Author(s):  
Andrey SOROKIN ◽  
Marco FOSCHI ◽  
Michael J. DUNN

The molecular mechanisms of endothelin (ET)-dependent activation of extracellular signal-regulated kinase (ERK)and p38 mitogen-activated protein (MAP) kinase were studied in rat and human renal glomerular mesangial cells. ET-1 induced a rapid and transient activation of Ras in renal mesangial cells, which was dependent upon the formation of the Shc/Grb2/Sos1 signalling complex and resulted in transient ERK activation. We have observed that Pyk2, a calcium-dependent cytoplasmic tyrosine kinase, was expressed in human renal mesangial cells and was tyrosine phosphorylated after ET-1 treatment. ET-1-induced activation of p38 MAPK pathway (but not ERK pathway) was inhibited in human and in rat glomerular mesangial cells expressing dominant-negative form of Pyk2, suggesting the engagement of Pyk2 in ET-1-mediated activation of p38 MAP kinase cascade. Contractive responsiveness of renal mesangial cells was shown to depend on activation of the p38 MAP kinases. Thus, p38 MAP kinase stimulation could perhaps partially account for ET-1 contractive properties, whereas ET-1-induced cell proliferation occurs primarily via Ras-dependent activation of the ERK.


2002 ◽  
Vol 80 (5) ◽  
pp. 375-382 ◽  
Author(s):  
Louis M Luttrell

Over the past decade, it has become apparent that many G-protein-coupled receptors (GPCRs) generate signals that control cellular differentiation and growth, including stimulation of Ras family GTPases and activation of mitogen-activated protein (MAP) kinase pathways. The mechanisms that GPCRs use to control the activity of MAP kinases vary between receptor and cell type but fall broadly into one of three categories: signals initiated by classical G protein effectors, e.g., protein kinase (PK)A and PKC, signals initiated by cross-talk between GPCRs and classical receptor tyrosine kinases, e.g., "transactivation" of epidermal growth factor (EGF) receptors, and signals initiated by direct interaction between β-arrestins and components of the MAP kinase cascade, e.g., β-arrestin "scaffolds". While each of these pathways results in increased cellular MAP kinase activity, emerging data suggest that they are not functionally redundant. MAP kinase activation occurring via PKC-dependent pathways and EGF receptor transactivation leads to nuclear translocation of the kinase and stimulates cell proliferation, while MAP kinase activation via β-arrestin scaffolds primarily increases cytosolic kinase activity. By controlling the spatial and temporal distribution of MAP kinase activity within the cell, the consequences of GPCR-stimulated MAP kinase activation may be determined by the mechanism by which they are activated.Key words: G-protein-coupled receptor, receptor tyrosine kinase, β-arrestin, mitogen-activated protein kinase, extracellular signal-regulated kinase.


2000 ◽  
Vol 345 (2) ◽  
pp. 217-224 ◽  
Author(s):  
Margarete GOPPELT-STRUEBE ◽  
Stefanie FICKEL ◽  
Christian O. A. REISER

In renal mesangial cells, activation of protein tyrosine kinase receptors may increase the activity of mitogen-activated protein (MAP) kinases and subsequently induce expression of prostaglandin G/H synthase-2 (PGHS-2, cyclo-oxygenase-2). As examples, platelet-derived growth factor (PDGF) and epidermal growth factor (EGF) were shown to transiently enhance p42/44 MAP kinase activity, which was an essential step in the induction of PGHS-2 mRNA and protein. Inhibitors of receptor kinase activities, tyrphostins AG1296 and AG1478, specifically inhibited the effects of PDGF and EGF respectively. Activation of p42/44 and p38 MAP kinases and PGHS-2 induction were also mediated by lysophosphatidic acid (LPA), which binds to pertussis-toxin-sensitive G-protein-coupled receptors. LPA stimulation was inhibited by AG1296, but not AG1478, indicating involvement of the PDGF receptor kinase in LPA-mediated signalling. This was confirmed by pertussis-toxin-sensitive tyrosine phosphorylation of the PDGF receptor by LPA, whereas no phosphorylation of the EGF receptor was detected. For comparison, 5-hydroxytryptamine (‘serotonin’)-mediated signalling was only partially inhibited by AG1296, and also not affected by AG1478. A strong basal AG1296-sensitive tyrosine phosphorylation of the PDGF receptor and a set of other proteins was observed, which by itself was not sufficient to induce p42/44 MAP kinase activation, but played an essential role not only in LPA- but also in phorbol ester-mediated activation. Taken together, the PDGF receptor, but not the EGF receptor, is involved in LPA-mediated MAP kinase activation and PGHS-2 induction in primary mesangial cells, where both protein kinase receptors are present and functionally active.


1992 ◽  
Vol 287 (2) ◽  
pp. 589-594 ◽  
Author(s):  
Y Wang ◽  
M S Simonson ◽  
J Pouysségur ◽  
M J Dunn

Mitogen-activated protein (MAP) kinases are regarded as switch kinases in the phosphorylation cascade initiated by various agonists. We have investigated whether endothelins (ET), which are constrictor and mitogenic isopeptides, can increase MAP kinase activity in rat mesangial cells, using bovine myelin basic protein (MBP) as a substrate for an in vitro kinase assay. Treatment of quiescent mesangial cells with ET-1 rapidly stimulated a kinase activity which phosphorylated exogenous MBP. This stimulation was dose-dependent, with threshold responses at 1 nM-ET-1. Epidermal growth factor and thrombin also activated this kinase in mesangial cells. We also examined the ET signal transduction pathways leading to activation of MBP kinase. Pertussis toxin had no effect on ET-stimulated MBP kinase activity. Stimulation of protein kinase C by phorbol ester increased MBP kinase activity, and down-regulation of PKC partially inhibited ET-stimulated MBP kinase as well as phorbol ester-stimulated MBP kinase activity. Interestingly, genestein, an inhibitor of protein tyrosine kinases, partially inhibited MBP kinase stimulated by ET but not by phorbol esters. These results suggest that ET stimulates MBP kinase activity in rat mesangial cells via at least two pathways: one which is protein kinase C-dependent and a second one that involves a protein tyrosine kinase. Finally, by raising rabbit antibodies against the two forms of MAP kinase, p44mapk and p42mapk, we demonstrated that both isoforms are expressed in mesangial cells. Antibody alpha 1 Cp42 specifically immunoprecipitated p42mapk and allowed us to demonstrate that ET stimulates MBP kinase activity in the p42mapk immunocomplex. In conclusion, we have provided evidence that, in rat mesangial cells, MAP kinases are rapidly activated by ET-1, a regulatory process that involves at least protein kinase C activation and also a contribution of a tyrosine kinase not yet characterized.


1993 ◽  
Vol 122 (5) ◽  
pp. 1089-1101 ◽  
Author(s):  
FA Gonzalez ◽  
A Seth ◽  
DL Raden ◽  
DS Bowman ◽  
FS Fay ◽  
...  

The mitogen-activated protein (MAP) kinase signal transduction pathway represents an important mechanism by which growth factors regulate cell function. Targets of the MAP kinase pathway are located within several cellular compartments. Signal transduction therefore requires the localization of MAP kinase in each sub-cellular compartment that contains physiologically relevant substrates. Here, we show that serum treatment causes the translocation of two human MAP kinase isoforms, p40mapk and p41mapk, from the cytosol into the nucleus. In addition, we report that p41mapk (but not p40mapk) is localized at the cell surface ruffling membrane in serum-treated cells. To investigate whether the protein kinase activity of MAP kinase is required for serum-induced redistribution within the cell, we constructed mutated kinase-negative forms of p40mapk and p41mapk. The kinase-negative MAP kinases were not observed to localize to the cell surface ruffling membrane. In contrast, the kinase-negative MAP kinases were observed to be translocated to the nucleus. Intrinsic MAP kinase activity is therefore required only for localization at the cell surface and is not required for transport into the nucleus. Together, these data demonstrate that the pattern of serum-induced redistribution of p40mapk is different from p41mapk. Thus, in addition to common targets of signal transduction, it is possible that these MAP kinase isoforms may differentially regulate targets located in distinct sub-cellular compartments.


1993 ◽  
Vol 13 (9) ◽  
pp. 5738-5748
Author(s):  
B M Yashar ◽  
C Kelley ◽  
K Yee ◽  
B Errede ◽  
L I Zon

Mitogen-activated protein (MAP) kinases comprise an evolutionarily conserved family of proteins that includes at least three vertebrate protein kinases (p42, p44, and p55 MAPK) and five yeast protein kinases (SPK1, MPK1, HOG1, FUS3, and KSS1). Members of this family are activated by a variety of extracellular agents that influence cellular proliferation and differentiation. In Saccharomyces cerevisiae, there are multiple physiologically distinct MAP kinase activation pathways composed of structurally related kinases. The recently cloned vertebrate MAP kinase activators are structurally related to MAP kinase activators in these yeast pathways. These similarities suggest that homologous kinase cascades are utilized for signal transduction in many, if not all, eukaryotes. We have identified additional members of the MAP kinase activator family in Xenopus laevis by a polymerase chain reaction-based analysis of embryonic cDNAs. One of the clones identified (XMEK2) encodes a unique predicted protein kinase that is similar to the previously reported activator (MAPKK) in X. laevis. XMEK2, a highly expressed maternal mRNA, is developmentally regulated during embryogenesis and expressed in brain and muscle. Expression of XMEK2 in yeast cells suppressed the growth defect associated with loss of the yeast MAP kinase activator homologs, MKK1 and MKK2. Partial sequence of a second cDNA clone (XMEK3) identified yet another potential MAP kinase activator. The pattern of expression of XMEK3 is distinct from that of p42 MAPK and XMEK2. The high degree of amino acid sequence similarity of XMEK2, XMEK3, and MAPKK suggests that these three are related members of an amphibian family of protein kinases involved in the activation of MAP kinase. Discovery of this family suggests that multiple MAP kinase activation pathways similar to those in yeast cells exist in vertebrates.


1992 ◽  
Vol 287 (1) ◽  
pp. 269-276 ◽  
Author(s):  
M R Gold ◽  
J S Sanghera ◽  
J Stewart ◽  
S L Pelech

Cross-linking of membrane immunoglobulin (mIg), the B lymphocyte antigen receptor, with anti-receptor antibodies stimulates tyrosine phosphorylation of a number of proteins, including one of 42 kDa. Proteins with a similar molecular mass are tyrosine-phosphorylated in response to receptor stimulation in other cell types and have been identified as serine/threonine kinases, termed mitogen-activated protein (MAP) kinases or extracellular signal-regulated kinases (ERKs). The MAP kinases constitute a family of related kinases, at least three of which have molecular masses of 40-45 kDa. In this paper we show that mIg cross-linking stimulated the myelin basic protein phosphotransferase activity characteristic of MAP kinase in both mature and immature murine B cell lines. This enzyme activity co-purified on three different columns with a 42 kDa protein that was tyrosine-phosphorylated (pp42) in response to mIg cross-linking and which reacted with a panel of anti-(MAP kinase) antibodies. Although immunoblotting with the anti-(MAP kinase) antibodies showed that these B cell lines expressed both 42 kDa and 44 kDa forms of MAP kinase, only the 42 kDa form was activated and tyrosine-phosphorylated to a significant extent. Activation of protein kinase C (PKC) with phorbol esters also resulted in selective tyrosine phosphorylation and activation of the 42 kDa MAP kinase. This suggested that mIg-induced MAP kinase activation could be due to stimulation of PKC by mIg. However, mIg-stimulated MAP kinase activation and pp42 tyrosine phosphorylation was only partially blocked by a PKC inhibitor, the staurosporine analogue Compound 3. In contrast, Compound 3 completely blocked the ability of phorbol esters to stimulate MAP kinase activity and induce tyrosine phosphorylation of pp42. Thus mIg may activate MAP kinase by both PKC-dependent and -independent mechanisms.


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