scholarly journals Calcium-regulated protein tyrosine phosphorylation is required for endothelin-1 to induce prostaglandin endoperoxide synthase-2 mRNA expression and protein synthesis in mesangial cells.

1997 ◽  
Vol 8 (7) ◽  
pp. 1080-1090
Author(s):  
E J Coroneos ◽  
M Kester ◽  
J Maclouf ◽  
P Thomas ◽  
M J Dunn

The role of endothelin (ET)-1-mediated cytosolic calcium ([Ca2+]i) elevation in regulating ET-1-induced prostaglandin endoperoxide synthase, prostaglandin G/H synthase (PGHS)-2 mRNA expression and protein synthesis was investigated in mesangial cells (MC). Ionomycin, a calcium ionophore, and thapsigargin, an inhibitor of calcium ATPase, mimicked the ET-1-stimulated PGHS-2 mRNA and protein induction. Inhibition of [Ca2+]i increases with (2-¿C2-bis-(carboxymethyl)-amino-5 methylphenoxy]methyl¿-6-methoxy-8-bis-(carboxymethyl)-aminoquinoline tetra-(acetoxymethyl)ester (Quin/AM), a calcium chelator, or with the combined presence of [8-(diethylamino)-octyl-3,4,5-trimethoxybenzoate, HCl] (TMB), an inhibitor of intracellular calcium stores release, and ethyleneglycol-bis-(beta-aminoethyl)- N,N,N',N'-tetra-acetic acid (EGTA) suppressed ET-1, as well as ionomycin and thapsigargin-mediated PGHS-2 mRNA and protein formation. Also, the ET-1-, ionomycin-, and thapsigargin-induced PGHS-2 mRNA expression and protein formation was inhibited in MC pretreated with inhibitors of calcium calmodulin kinase. In contrast, these conditions did not inhibit interleukin (IL)-1-induced PGHS-2 mRNA expression and protein synthesis. Pretreatment with tyrosine kinase inhibitors abolished the ET-1-, ionomycin-, thapsigargin-, and IL-1-mediated PGHS-2 mRNA and protein induction. ET-1-, ionomycin-, and thapsigargin- induced protein tyrosine phosphorylation, but not IL-1-induced protein tyrosine phosphorylation, was suppressed by inhibiting either [Ca2+]i elevation or calcium calmodulin kinase activation. It was concluded that elevation of [Ca2+]i and activation of calcium calmodulin kinases are upstream mediators of ET-1-induced PGHS-2 gene expression through activation of non-receptor-linked protein tyrosine kinase in MC.

1998 ◽  
Vol 275 (3) ◽  
pp. F343-F352 ◽  
Author(s):  
Samir S. El-Dahr ◽  
Susana Dipp ◽  
William H. Baricos

Among its diverse biological actions, the vasoactive peptide bradykinin (BK) induces the transcription factor AP-1 and proliferation of mesangial cells (S. S. El-Dahr, S. Dipp, I. V. Yosipiv, and W. H. Baricos. Kidney Int. 50: 1850–1855, 1996). In the present study, we examined the role of protein tyrosine phosphorylation and the mitogen-activated protein kinases, ERK1/2,in mediating BK-induced AP-1 and DNA replication in cultured rat mesangial cells. BK (10−9 to 10−7 M) stimulated a rapid increase in tyrosine phosphorylation of multiple proteins with an estimated molecular mass of 120–130, 90–95, and 44–42 kDa. Immunoblots using antibodies specific for ERK or tyrosine-phosphorylated ERK revealed a shifting of p42 ERK2 to a higher molecular weight that correlated temporally with an increase in tyrosine-phosphorylated ERK2. Genistein, a specific tyrosine kinase inhibitor, prevented the phosphorylation of ERK2 by BK. In-gel kinase assays indicated that BK-induced tyrosine phosphorylation of ERK2 is accompanied by fourfold activation of its phosphotransferase activity toward the substrate PHAS-I ( P < 0.05). Furthermore, BK stimulated a 2.5-fold increase ( P < 0.05) in phosphorylation of Elk-1, a transcription factor required for growth factor-induced c-fos transcription. In accord with the stimulation of Elk-1 phosphorylation, BK induced c-fos gene expression and the production of Fos/AP-1 complexes. In addition, thymidine incorporation into DNA increased twofold ( P < 0.05) following BK stimulation. Each of these effects was blocked by tyrosine kinase inhibition with genistein or herbimycin A. Similarly, antisense oligodeoxynucleotide targeting of ERK1/2 mRNA inhibited BK-stimulated DNA synthesis. In contrast, protein kinase C inhibition or depletion had no effect on BK-induced c-fos mRNA, AP-1-DNA binding activity, or DNA synthesis. Collectively, these data demonstrate that BK activates the ERK→Elk-1→AP-1 pathway and that BK mitogenic signaling is critically dependent on protein tyrosine phosphorylation.


Blood ◽  
1991 ◽  
Vol 78 (8) ◽  
pp. 1928-1935 ◽  
Author(s):  
K Okuda ◽  
B Druker ◽  
Y Kanakura ◽  
M Koenigsmann ◽  
JD Griffin

Abstract Granulocyte-macrophage colony-stimulating factor (GM-CSF) exerts its biologic activities through binding to specific high-affinity cell surface receptors. After binding, the ligand/receptor complex is rapidly internalized in most hematopoietic cells. Using a human factor- dependent cell line, MO7, and normal human neutrophils, we found that the internalization is exquisitely temperature-dependent, such that ligand/receptor internalization does not detectably occur at 4 degrees C. Activation of the GM-CSF receptor has previously been shown to stimulate a number of postreceptor signal transduction pathways, including activation of a tyrosine kinase and activation of the serine/threonine kinase, Raf-1. The GM-CSF-stimulated increase in tyrosine kinase activity occurs rapidly at both 4 degrees C and 37 degrees C, and therefore is likely to be independent of receptor internalization. At 37 degrees C, the protein tyrosine phosphorylation was transient in MO7 cells, with maximum phosphorylation observed after 5 to 15 minutes, followed by a rapid decline. At 4 degrees C, the protein tyrosine phosphorylation of the same substrates was greater than at 37 degrees C, and no decline in substrate phosphorylation was observed for at least 90 minutes. In contrast to tyrosine phosphorylation, the activation and hyper-phosphorylation of Raf-1 observed at 37 degrees C in both MO7 cells and neutrophils was markedly diminished at 4 degrees C. These results indicate that at least one postreceptor signal transduction mechanism, activation of a tyrosine kinase, does not require ligand/receptor internalization, and indicate that receptor internalization may be a consequence, rather than the initiator, of signal transduction.


1998 ◽  
Vol 274 (2) ◽  
pp. H513-H519 ◽  
Author(s):  
Susan A. Kelly ◽  
Pascal J. Goldschmidt-Clermont ◽  
Emily E. Milliken ◽  
Toshiyuki Arai ◽  
Elise H. Smith ◽  
...  

Proinflammatory cytokines initiate the vascular inflammatory response via the upregulation of adhesion molecules on the luminal endothelial surface. We investigated directly the role of protein tyrosine phosphorylation in the upregulation of the endothelial adhesion molecules, intercellular adhesion molecule 1 (ICAM-1) and E-selectin, and the consequent adhesion of neutrophils, after tumor necrosis factor (TNF)-α-stimulation of human aortic endothelial cells in vitro. Time- and dose-dependent TNF-α-stimulated ICAM-1 and E-selectin upregulation and neutrophil adhesion each were suppressed by tyrosine kinase inhibitors, including genistein (200 μM), but not genistin, its isoflavone analog without tyrosine kinase inhibitory activity. Tyrphostin AG 126, a synthetic selective tyrosine kinase inhibitor, also suppressed ICAM-1 and E-selectin upregulation and neutrophil adhesion, each in a dose-dependent manner, whereas tyrphostin AG 1288 had no effect. Tyrosine phosphorylation of two proteins (85 and 145 kDa in the cytoskeleton fraction) found minutes after TNF-α-stimulation was also inhibited by genistein. These findings suggest that, in endothelial cells, TNF-α upregulates ICAM-1 and E-selectin expression and consequent neutrophil adhesion via protein tyrosine phosphorylation.


Blood ◽  
1994 ◽  
Vol 84 (1) ◽  
pp. 94-103
Author(s):  
D Linnekin ◽  
OM Howard ◽  
L Park ◽  
W Farrar ◽  
D Ferris ◽  
...  

The human myeloid cell line HL-60 expresses approximately 300 high- affinity granulocyte-macrophage colony-stimulating factor receptors (GM- CSFRs), yet treatment of these cells with GM-CSF does not result in enhanced cellular proliferation or increases in protein tyrosine phosphorylation. In contrast, GM-CSF induces rapid increases in protein tyrosine phosphorylation and proliferative responses in HL-60 cells pretreated for 3 days in dimethyl sulfoxide (DMSO). Similarly, HL-60 cells pretreated with retinoic acid or 1,25 dihydroxyvitamin D3 were also capable of responding to GM-CSF. Interestingly, each of these treatments resulted in increased expression of the src-like tyrosine kinase hck. Stimulation with GM-CSF increased hck autophosphorylation in DMSO-treated HL-60 cells, suggesting that hck is a component of the GM-CSF signal transduction pathway. To determine if hck has a role in the DMSO-induced recoupling of the GM-CSFR, we overexpressed hck in HL- 60 cells. The resulting cell line (HL-60/hck) expresses hck mRNA and protein at levels comparable with DMSO-treated HL-60 cells. Stimulation of HL-60/hck cells with GM-CSF results in activation of hck, increases in protein tyrosine phosphorylation, and increased proliferation. These results show that cytokine receptors can exist in an uncoupled form and suggest that in HL-60 cells, appropriate levels of the src-like tyrosine kinase hck are critical for functional coupling of the GM-CSFR to biologic responses.


Blood ◽  
1997 ◽  
Vol 89 (5) ◽  
pp. 1590-1598 ◽  
Author(s):  
Mutsumasa Yanabu ◽  
Yukio Ozaki ◽  
Shosaku Nomura ◽  
Tetsuya Miyake ◽  
Yasuhiko Miyazaki ◽  
...  

Abstract NNKY5-5, an IgG monoclonal antibody directed against the von Willebrand factor-binding domain of glycoprotein (GP) Ibα, induced weak but irreversible aggregation (or association) of platelets in citrate-anticoagulated platelet-rich plasma. This phenomenon was defined as small aggregate formation (SAF ). Platelets in hirudin-anticoagulated plasma or washed platelets showed little response to NNKY5-5 alone, but the antibody potentiated aggregation induced by low concentrations of adenosine diphosphate or platelet-activating factor. NNKY5-5 did not induce granule release or intracellular Ca2+ mobilization. However, NNKY5-5 caused tyrosine phosphorylation of a 64-kD protein and activation of a tyrosine kinase, p72syk. An anti-FcγII receptor antibody had no effect on SAF, suggesting that NNKY5-5 activated platelets by interacting with glycoprotein Ib. Fab′ fragments of NNKY5-5 did not induce SAF, but potentiated aggregation induced by other agonists. The Fab′ fragment of NNKY5-5 induced the activation of p72syk, suggesting that such activation was independent of the FcγII receptor. Cross-linking of the receptor-bound Fab′ fragment of NNKY5-5 with a secondary antibody induced SAF. GRGDS peptide, chelation of extracellular Ca2+, and an anti-GPIIb/IIIa antibody inhibited NNKY5-5-induced SAF, but had no effect on 64-kD protein tyrosine phosphorylation or p72syk activations. Various inhibitors, including aspirin and protein kinase C, had no effect on SAF, protein tyrosine phosphorylation, or p72syk activation. In contrast, tyrphostin 47, a potent tyrosine kinase inhibitor, inhibited NNKY5-5–induced SAF as well as tyrosine phosphorylation and p72syk activation. Our findings suggest that binding of NNKY5-5 to GPIb potentiates platelet aggregation by facilitating the interaction between fibrinogen and GPIIb/IIIa through a mechanism associated with p72syk activation and tyrosine phosphorylation of a 64-kD protein.


Blood ◽  
1994 ◽  
Vol 84 (1) ◽  
pp. 94-103 ◽  
Author(s):  
D Linnekin ◽  
OM Howard ◽  
L Park ◽  
W Farrar ◽  
D Ferris ◽  
...  

Abstract The human myeloid cell line HL-60 expresses approximately 300 high- affinity granulocyte-macrophage colony-stimulating factor receptors (GM- CSFRs), yet treatment of these cells with GM-CSF does not result in enhanced cellular proliferation or increases in protein tyrosine phosphorylation. In contrast, GM-CSF induces rapid increases in protein tyrosine phosphorylation and proliferative responses in HL-60 cells pretreated for 3 days in dimethyl sulfoxide (DMSO). Similarly, HL-60 cells pretreated with retinoic acid or 1,25 dihydroxyvitamin D3 were also capable of responding to GM-CSF. Interestingly, each of these treatments resulted in increased expression of the src-like tyrosine kinase hck. Stimulation with GM-CSF increased hck autophosphorylation in DMSO-treated HL-60 cells, suggesting that hck is a component of the GM-CSF signal transduction pathway. To determine if hck has a role in the DMSO-induced recoupling of the GM-CSFR, we overexpressed hck in HL- 60 cells. The resulting cell line (HL-60/hck) expresses hck mRNA and protein at levels comparable with DMSO-treated HL-60 cells. Stimulation of HL-60/hck cells with GM-CSF results in activation of hck, increases in protein tyrosine phosphorylation, and increased proliferation. These results show that cytokine receptors can exist in an uncoupled form and suggest that in HL-60 cells, appropriate levels of the src-like tyrosine kinase hck are critical for functional coupling of the GM-CSFR to biologic responses.


1996 ◽  
Vol 271 (3) ◽  
pp. L400-L408 ◽  
Author(s):  
V. Natarajan ◽  
S. Vepa ◽  
R. S. Verma ◽  
W. M. Scribner

Oxidant-induced activation of phospholipase D (PLD) in bovine pulmonary artery endothelial cells (BPAEC) is independent of protein kinase C and calcium. In the present study, the effects of tyrosine kinase and protein tyrosine phosphatase (PTPase) inhibitors on hydrogen peroxide (H2O2)-induced PLD activation and protein tyrosine phosphorylation were examined in BPAEC. Pretreatment of BPAEC with putative tyrosine kinase inhibitors genistein, tyrphostin, and herbimycin attenuated H2O2 (1 mM)-induced PLD activation. The inhibitory effect of the tyrosine kinase inhibitors was highly specific for H2O2-induced modulation and showed no effect on PLD activation mediated by 12-O-tetradecanoylphorbol 13-acetate or bradykinin. Furthermore, addition of H2O2 increased in a time-dependent manner tyrosine phosphorylation of several proteins (17-200 kDa), as determined by immunoblot analysis with antiphosphotyrosine antibodies. H2O2-mediated protein tyrosine phosphorylation preceded PLD activation, and a good correlation was observed on the effect of genistein in H2O2-induced PLD activation and protein tyrosine phosphorylation. Addition of vanadate, a phosphotyrosine phosphatase inhibitor, synergistically increased both PLD activation and protein tyrosine phosphorylation mediated by H2O2. Moreover, vanadate by itself had minimal effect on basal PLD activity in BPAEC; however, at 10 microM vanadate, an increase in protein tyrosine phosphorylation was observed. In addition to vanadate, phenylarsine oxide and diamide potentiated H2O2-induced PLD activation. These results suggest that tyrosine kinase activation may be involved in H2O2-induced PLD activation in vascular endothelial cells.


1994 ◽  
Vol 126 (4) ◽  
pp. 1111-1121 ◽  
Author(s):  
G Berton ◽  
L Fumagalli ◽  
C Laudanna ◽  
C Sorio

Stimulation of adherent human neutrophils (PMN) with tumor necrosis factor (TNF) triggers protein tyrosine phosphorylation (Fuortes, M., W. W. Jin, and C. Nathan. 1993. J. Cell Biol. 120:777-784). We investigated the dependence of this response on beta 2 integrins by using PMN isolated from a leukocyte adhesion deficiency (LAD) patient, which do not express beta 2 integrins, and by plating PMN on surface bound anti-beta 2 (CD18) antibodies. Protein tyrosine phosphorylation increased in PMN plated on fibrinogen and this phosphorylation was enhanced by TNF. Triggering of protein tyrosine phosphorylation did not occur in LAD PMN plated on fibrinogen either in the absence or the presence of TNF. Surface bound anti-CD18, but not isotype-matched anti-Class I major histocompatibility complex (MHC) antigens, antibodies triggered tyrosine phosphorylation in normal, but not in LAD PMN. As the major tyrosine phosphorylated proteins we found in our assay conditions migrated with an apparent molecular mass of 56-60 kD, we investigated whether beta 2 integrins are implicated in activation of members of the src family of intracellular protein-tyrosine kinases. We found that the fgr protein-tyrosine kinase (p58fgr) activity, and its extent of phosphorylation in tyrosine, in PMN adherent to fibrinogen, was enhanced by TNF. Activation of p58fgr in response to TNF was evident within 10 min of treatment and increased with times up to 30 min. Also other activators of beta 2 integrins such as phorbol-12-myristate 13-acetate (PMA), and formyl methionyl-leucyl-phenylalanine (FMLP), induced activation of p58fgr kinase activity. Activation of p58fgr kinase activity, and phosphorylation in tyrosine, did not occur in PMN of a LAD patient in response to TNF. Soluble anti-CD18, but not anti-Class I MHC antigens, antibodies inhibited activation of p58fgr kinase activity in PMN adherent to fibrinogen in response to TNF, PMA, and FMLP. These findings demonstrate that, in PMN, beta 2 integrins are implicated in triggering of protein tyrosine phosphorylation, and establish a link between beta 2 integrin-dependent adhesion and the protein tyrosine kinase fgr in cell signaling.


Sign in / Sign up

Export Citation Format

Share Document