SemOpenAlex |

SemOpenAlex

Matches in SemOpenAlex for { <https://semopenalex.org/work/W2017996683> ?p ?o ?g. }

Showing items 1 to 100 of ±124 with 100 items per page.

W2017996683 endingPage "34698" @default.
W2017996683 startingPage "34691" @default.
W2017996683 abstract "Stimulation of phospholipase D (PLD) in HEK-293 cells expressing the M3 muscarinic receptor by phorbol ester-activated protein kinase C (PKC) apparently involves Ral GTPases. We report here that PKC, but not muscarinic receptor-induced PLD stimulation in these cells, is strongly and specifically reduced by expression of dominant-negative RalA, G26A RalA, as well as dominant-negative Ras, S17N Ras. In contrast, overexpression of the Ras-activated Ral-specific guanine nucleotide exchange factor, Ral-GDS, specifically enhanced PKC-induced PLD stimulation. Moreover, recombinant Ral-GDS potentiated Ral-dependent PKC-induced PLD stimulation in membranes. Epidermal growth factor, platelet-derived growth factor, and insulin, ligands for receptor tyrosine kinases (RTKs) endogenously expressed in HEK-293 cells, apparently use the PKC- and Ras/Ral-dependent pathway for PLD stimulation. First, PLD stimulation by the RTK agonists was prevented by PKC inhibition and PKC down-regulation. Second, expression of dominant-negative RalA and Ras mutants strongly reduced RTK-induced PLD stimulation. Third, overexpression of Ral-GDS largely potentiated PLD stimulation by the RTK agonists. Finally, using the Ral binding domain of the Ral effector RLIP as an activation-specific probe for Ral proteins, it is demonstrated that endogenous RalA is activated by phorbol ester and RTK agonists. Taken together, strong evidence is provided that RTK-induced PLD stimulation in HEK-293 cells is mediated by PKC and a Ras/Ral signaling cascade. Stimulation of phospholipase D (PLD) in HEK-293 cells expressing the M3 muscarinic receptor by phorbol ester-activated protein kinase C (PKC) apparently involves Ral GTPases. We report here that PKC, but not muscarinic receptor-induced PLD stimulation in these cells, is strongly and specifically reduced by expression of dominant-negative RalA, G26A RalA, as well as dominant-negative Ras, S17N Ras. In contrast, overexpression of the Ras-activated Ral-specific guanine nucleotide exchange factor, Ral-GDS, specifically enhanced PKC-induced PLD stimulation. Moreover, recombinant Ral-GDS potentiated Ral-dependent PKC-induced PLD stimulation in membranes. Epidermal growth factor, platelet-derived growth factor, and insulin, ligands for receptor tyrosine kinases (RTKs) endogenously expressed in HEK-293 cells, apparently use the PKC- and Ras/Ral-dependent pathway for PLD stimulation. First, PLD stimulation by the RTK agonists was prevented by PKC inhibition and PKC down-regulation. Second, expression of dominant-negative RalA and Ras mutants strongly reduced RTK-induced PLD stimulation. Third, overexpression of Ral-GDS largely potentiated PLD stimulation by the RTK agonists. Finally, using the Ral binding domain of the Ral effector RLIP as an activation-specific probe for Ral proteins, it is demonstrated that endogenous RalA is activated by phorbol ester and RTK agonists. Taken together, strong evidence is provided that RTK-induced PLD stimulation in HEK-293 cells is mediated by PKC and a Ras/Ral signaling cascade. phospholipase D protein kinase C receptor tyrosine kinase phosphatidylcholine muscarinic acetylcholine receptor ADP-ribosylation factor guanine nucleotide exchange factor phorbol 12-myristate 13-acetate epidermal growth factor 5)P2, phosphatidylinositol 4,5-bisphosphate platelet-derived growth factor Ral binding domain glutathione S-transferase mitogen-activated protein kinase polyacrylamide gel electrophoresis phosphatidylethanol Phospholipase D (PLD)1catalyzes formation of phosphatidic acid from the major membrane phospholipid, phosphatidylcholine (PtdCho), and this reaction is implicated in the regulation of diverse cellular processes, such as vesicular trafficking and cell growth and differentiation. A large variety of receptor tyrosine kinases (RTKs) and receptors coupled to heterotrimeric G proteins in a wide range of cell types has been reported to mediate PLD stimulation in response to their specific agonists. However, the mechanisms of receptor signaling to PLD in intact cells are only poorly understood and seem to involve distinct signal transduction components, in particular different small GTPases and protein kinase C (PKC) isoforms (for reviews, see Refs. 1Exton J.H. J. Biol. Chem. 1997; 272: 15579-15582Abstract Full Text Full Text PDF PubMed Scopus (284) Google Scholar, 2Singer W.D. Brown H.A. Sternweis P.C. Annu. Rev. Biochem. 1997; 66: 475-509Crossref PubMed Scopus (347) Google Scholar, 3Cockcroft S. Prog. Lipid Res. 1997; 35: 345-370Crossref Scopus (55) Google Scholar, 4Morris A.J. Engebrecht J. Frohman M.A. Trends Biochem. Sci. 1996; 17: 182-185Scopus (175) Google Scholar, 5Exton J.H. Physiol. Rev. 1997; 77: 303-320Crossref PubMed Scopus (386) Google Scholar).In HEK-293 cells, stably expressing the M3 muscarinic acetylcholine receptor (mAChR), GTPases of distinct families, such as ADP-ribosylation factor (ARF), Rho, and Ral, as well as various protein kinases, such as PKC, Rho kinase, and tyrosine kinases, apparently mediate PLD activation. Specifically, stimulation of PLD by the G protein-coupled M3 mAChR is dependent on ARF and Rho GTPases and apparently involves a tyrosine kinase and Rho kinase but not PKC. On the other hand, PLD stimulation by phorbol ester-activated PKC, which is phosphorylation-dependent in HEK-293 cells, is apparently ARF-independent and only poorly inhibited by inactivation of Rho proteins (6Rümenapp U. Geiszt M. Friederike W. Schmidt M. Jakobs K.H. Eur. J. Biochem. 1995; 324: 240-244Crossref Scopus (81) Google Scholar, 7Schmidt M. Rümenapp U. Bienek C. Keller J. von Eichel-Streiber C. Jakobs K.H. J. Biol. Chem. 1996; 271: 2422-2426Abstract Full Text Full Text PDF PubMed Scopus (107) Google Scholar, 8Schürmann A. Schmidt M. Asmus M. Bayer S. Fliegert F. Kolin S. Maßmann S. Schilf C. Subauste M.C. Voß M. Jakobs K.H. Joost H.-G. J. Biol. Chem. 1999; 274: 9744-9751Abstract Full Text Full Text PDF PubMed Scopus (27) Google Scholar, 9Schmidt M. Voß M. Oude Weernink P.A. Wetzel J. Amano M. Kaibuchi K. Jakobs K.H. J. Biol. Chem. 1999; 274: 14648-14654Abstract Full Text Full Text PDF PubMed Scopus (76) Google Scholar, 10Schmidt M. Hüwe S.M. Fasselt B. Homann D. Rümenapp U. Sandmann J. Jakobs K.H. Eur. J. Biochem. 1994; 225: 667-675Crossref PubMed Scopus (88) Google Scholar, 11Rümenapp U. Schmidt M. Wahn F. Tapp E. Grannass A. Jakobs K.H. Eur. J. Biochem. 1997; 248: 407-414Crossref PubMed Scopus (23) Google Scholar). Recently, evidence has been provided that Ral GTPases are involved in PKC-induced PLD stimulation in HEK-293 cells (12Schmidt M. Voß M. Thiel M. Bauer B. Grannaß A. Tapp E. Cool R.H. de Gunzburg J. von Eichel-Streiber C. Jakobs K.H. J. Biol. Chem. 1998; 273: 7413-7422Abstract Full Text Full Text PDF PubMed Scopus (54) Google Scholar).Previously, Ral GTPases have been reported to be involved in Ras-mediated PLD activation in v-Src-transformed Balb/c- and NIH-3T3 fibroblasts (13Jiang H. Lu Z. Luo J.-Q. Wolfman A. Foster D.A. J. Biol. Chem. 1995; 270: 6006-6009Abstract Full Text Full Text PDF PubMed Scopus (86) Google Scholar, 14Jiang H. Luo J.-Q. Urano T. Frankel P. Lu Z. Foster D.A. Feig L.A. Nature. 1995; 378: 409-412Crossref PubMed Scopus (246) Google Scholar). Moreover, RalA has recently been shown to interact directly with PLD1 and to enhance ARF-stimulated PLD1 activity (15Luo J.-Q. Liu X. Hammond S.M. Colley W.C. Feig L.A. Frohman M.A. Morris A.J. Foster D.A. Biochem. Biophys. Res. Commun. 1997; 235: 854-859Crossref PubMed Scopus (79) Google Scholar, 16Luo J.-Q. Liu X. Frankel P. Rotunda T. Ramos M. Flom J. Jiang H. Feig L.A. Morris A.J. Kahn R.A. Foster D.A. Proc. Natl. Acad. Sci. U. S. A. 1998; 95: 3632-3637Crossref PubMed Scopus (119) Google Scholar, 17Kim J.H. Lee S.D. Han J.M. Lee T.G. Kim Y. Park J.B. Lambeth J.D. Suh P.-G. Ryu S.H. FEBS Lett. 1998; 430: 231-235Crossref PubMed Scopus (89) Google Scholar). As Ral proteins are activated by Ras-controlled Ral-specific guanine nucleotide exchange factors (Ral-GEFs), such as Ral-GDS, Rgl, and Rlf (for review, see Ref. 18Bos J.L. EMBO J. 1998; 17: 6776-6782Crossref PubMed Scopus (286) Google Scholar), Ral-induced PLD stimulation has been suggested to involve a Ras/Ral-GEF/Ral signaling cascade (14Jiang H. Luo J.-Q. Urano T. Frankel P. Lu Z. Foster D.A. Feig L.A. Nature. 1995; 378: 409-412Crossref PubMed Scopus (246) Google Scholar, 18Bos J.L. EMBO J. 1998; 17: 6776-6782Crossref PubMed Scopus (286) Google Scholar, 19Feig L.A. Urano T. Cantor S. Trends Biochem. Sci. 1996; 21: 438-441Abstract Full Text PDF PubMed Scopus (179) Google Scholar, 20Lacal J.C. FEBS Lett. 1997; 410: 341-347Crossref Scopus (61) Google Scholar, 21Voijtek A.B. Der C.J. J. Biol. Chem. 1998; 273: 19925-19928Abstract Full Text Full Text PDF PubMed Scopus (495) Google Scholar). Thus, the aim of this study was to examine the existence of a Ras/Ral signaling cascade in Ral-mediated PLD stimulation by PKC in HEK-293 cells and to identify receptors stimulating PLD by such a signaling pathway. We report here that the Ral-dependent PLD stimulation by PKC involves Ras and a Ral-GEF. Most important, it is demonstrated that PLD stimulation in HEK-293 cells by endogenously expressed RTKs is mediated by PKC and a Ras/Ral signaling pathway.DISCUSSIONIn the present study, we provide evidence that a Ras/Ral signaling cascade is involved in stimulation of PLD activity by PKC in HEK-293 cells. Furthermore, and most important, strong evidence is provided that PLD stimulation by RTKs for EGF, PDGF, and insulin, but not by the G protein-coupled M3 mAChR, expressed in these cells, is mediated by a PKC- and Ras/Ral-dependent signaling pathway. The evidence is based on the following major findings. First, similar to inactivation of Ral proteins by C. difficile toxin B-1470, expression of dominant-negative RalA largely and specifically reduced PLD stimulation by phorbol ester-activated PKC and ligand-activated RTKs. Second, expression of dominant-negative Ras resulted in a similar specific inhibition of PLD stimulation. Third, endogenously expressed RalA was activated by PKC and RTKs. Fourth, overexpression of the Ras-activated Ral-GEF, Ral-GDS, specifically potentiated PLD stimulation by PKC and RTKs in intact HEK-293 cells. Fifth, recombinant Ral-GDS potentiated PKC-induced PLD stimulation in membranes of HEK-293 cells in a Ral-dependent manner. Finally, PLD stimulation by each of the three RTK agonists,i.e. EGF, PDGF, and insulin, was fully prevented by PKC inhibition or PKC down-regulation.Previous studies in HEK-293 cells stably expressing the M3mAChR indicated that signaling to PLD is mediated by at least two distinct pathways. Stimulation of PLD by the G protein-coupled M3 mAChR is dependent on ARF and Rho GTPases and involves a tyrosine kinase and Rho kinase, acting apparently upstream and downstream of Rho proteins, respectively, but not PKC (6Rümenapp U. Geiszt M. Friederike W. Schmidt M. Jakobs K.H. Eur. J. Biochem. 1995; 324: 240-244Crossref Scopus (81) Google Scholar, 7Schmidt M. Rümenapp U. Bienek C. Keller J. von Eichel-Streiber C. Jakobs K.H. J. Biol. Chem. 1996; 271: 2422-2426Abstract Full Text Full Text PDF PubMed Scopus (107) Google Scholar, 8Schürmann A. Schmidt M. Asmus M. Bayer S. Fliegert F. Kolin S. Maßmann S. Schilf C. Subauste M.C. Voß M. Jakobs K.H. Joost H.-G. J. Biol. Chem. 1999; 274: 9744-9751Abstract Full Text Full Text PDF PubMed Scopus (27) Google Scholar, 9Schmidt M. Voß M. Oude Weernink P.A. Wetzel J. Amano M. Kaibuchi K. Jakobs K.H. J. Biol. Chem. 1999; 274: 14648-14654Abstract Full Text Full Text PDF PubMed Scopus (76) Google Scholar, 10Schmidt M. Hüwe S.M. Fasselt B. Homann D. Rümenapp U. Sandmann J. Jakobs K.H. Eur. J. Biochem. 1994; 225: 667-675Crossref PubMed Scopus (88) Google Scholar). In contrast, PLD stimulation by phorbol ester-activated PKC, which is phosphorylation-dependent in HEK-293 cells, apparently involves the Ras-related Ral GTPases (11Rümenapp U. Schmidt M. Wahn F. Tapp E. Grannass A. Jakobs K.H. Eur. J. Biochem. 1997; 248: 407-414Crossref PubMed Scopus (23) Google Scholar, 12Schmidt M. Voß M. Thiel M. Bauer B. Grannaß A. Tapp E. Cool R.H. de Gunzburg J. von Eichel-Streiber C. Jakobs K.H. J. Biol. Chem. 1998; 273: 7413-7422Abstract Full Text Full Text PDF PubMed Scopus (54) Google Scholar). As Ral proteins are activated by Ral-specific GEFs, such as Ral-GDS, Rgl, and Rlf, which are under control of Ras proteins (18Bos J.L. EMBO J. 1998; 17: 6776-6782Crossref PubMed Scopus (286) Google Scholar), we first wanted to know whether the PKC-induced PLD stimulation is mediated by a Ras/Ral signaling cascade. Expression of either dominant-negative Ras or RalA markedly and specifically reduced PKC-induced PLD stimulation. As dominant-negative G26A RalA, similar to dominant-negative S17N Ras, is constitutively in the GDP-bound form (18Bos J.L. EMBO J. 1998; 17: 6776-6782Crossref PubMed Scopus (286) Google Scholar, 22White M.A. Vale T. Camonis J.H. Schaefer E. Wigler M.H. J. Biol. Chem. 1996; 271: 16439-16442Abstract Full Text Full Text PDF PubMed Scopus (216) Google Scholar, 23Medema R.H. Wubbolts R. Bos J.L. Mol. Cell. Biol. 1991; 11: 5963-5967Crossref PubMed Scopus (110) Google Scholar, 24Burgering B.M.T. de Vries-Smits A.M. Medema R.H. van Weeren P.C . Tertoolen L.G. Bos J.L. Mol. Cell. Biol. 1993; 13: 7248-7256Crossref PubMed Scopus (151) Google Scholar), its inhibitory effect on PKC-induced PLD stimulation is probably due to sequestration of endogenous Ras-activated Ral-GEFs and, thus, interruption of a Ras/Ral-GEF/Ral signaling pathway. Furthermore, it is shown that overexpression of the ubiquitously expressed Ras-GEF, Ral-GDS, specifically enhanced PKC-induced PLD stimulation. Finally, recombinant Ral-GDS potentiated PKC-induced PLD stimulation in membranes of HEK-293 cells but only in the presence of functional Ral proteins. As Ral-GDS and Ral had no effect on basal PLD activity but required the presence of activated PKC and, on the other hand, efficient PLD stimulation by activated PKC required the presence of Ral (12Schmidt M. Voß M. Thiel M. Bauer B. Grannaß A. Tapp E. Cool R.H. de Gunzburg J. von Eichel-Streiber C. Jakobs K.H. J. Biol. Chem. 1998; 273: 7413-7422Abstract Full Text Full Text PDF PubMed Scopus (54) Google Scholar), it has to be concluded that for productive PKC-induced PLD stimulation in HEK-293 cells both PKC itself and the Ras/Ral-GEF-activated Ral GTPases are required. In line with a cooperative action of Ral and PKC on PLD activity, Del Pesoet al. (31Del Peso L. Lucas L. Esteve P. Lacal J.C. Biochem J. 1997; 322: 519-528Crossref PubMed Scopus (27) Google Scholar) report that phorbol ester-stimulated PLD activity is highly enhanced in NIH-3T3 cells expressing oncogenic Ras, which by itself had no or only a minor effect on basal PLD activity. As PMA induced activation of endogenous RalA in HEK-293 cells, it can additionally be concluded that PMA activates Ras and, as a consequence, Ral proteins. Recently, various mechanisms of Ras activation by phorbol esters have been reported (32El-Shemerly M.Y.M. Besser D. Nagasawa M. Nagamine Y. J. Biol. Chem. 1997; 272: 30599-30602Abstract Full Text Full Text PDF PubMed Scopus (65) Google Scholar, 33Marais R. Light Y. Mason C. Paterson H. Olson M.F. Marshall C.J. Science. 1998; 280: 109-112Crossref PubMed Scopus (398) Google Scholar, 34Ebinu J.O. Bottorff D.A. Chan E.Y.W. Stang S.L. Dunn R.J. Stone J.C. Science. 1998; 280: 1082-1086Crossref PubMed Scopus (545) Google Scholar). Which of these activation mechanisms is induced by PMA in HEK-293 cells remains to be determined.The second major aim of this study was to identify receptors mediating PLD stimulation by the PKC- and Ras/Ral-dependent pathway. As the G protein-coupled M3 mAChR obviously did not use this pathway for PLD stimulation, PLD stimulation by RTKs for EGF, PDGF, and insulin endogenously expressed in HEK-293 cells was examined. Here we demonstrate that these RTK agonists efficiently increased PLD activity and that this RTK action was completely blocked by PKC inhibition or PKC down-regulation. In line with this finding, which has also been reported for RTK-mediated PLD stimulation in various other cell types (for reviews, see Refs. 1Exton J.H. J. Biol. Chem. 1997; 272: 15579-15582Abstract Full Text Full Text PDF PubMed Scopus (284) Google Scholar, 2Singer W.D. Brown H.A. Sternweis P.C. Annu. Rev. Biochem. 1997; 66: 475-509Crossref PubMed Scopus (347) Google Scholar, 3Cockcroft S. Prog. Lipid Res. 1997; 35: 345-370Crossref Scopus (55) Google Scholar, 4Morris A.J. Engebrecht J. Frohman M.A. Trends Biochem. Sci. 1996; 17: 182-185Scopus (175) Google Scholar, 5Exton J.H. Physiol. Rev. 1997; 77: 303-320Crossref PubMed Scopus (386) Google Scholar), we observed that the three RTK agonists increased phospholipase C activity in HEK-293 cells and induced rather long-lasting translocation of PKC isoforms, most prominent of which is PKC-α, to membrane compartments (data not shown). Most important, similar to PKC-induced PLD stimulation, stimulation of RTK-mediated PLD activity was blocked by inactivation of Ras-related GTPases with C. difficile toxin B-1470 but not affected by inactivation of Rho GTPases with C. difficiletoxin B. Furthermore, expression of dominant-negative RalA specifically reduced RTK-mediated PLD stimulation without affecting MAP kinase activation. A similar reduction in RTK-mediated PLD stimulation was observed in cells expressing dominant-negative Ras. Finally, similar to PMA, RTK agonists activated endogenous RalA in HEK-293 cells, and overexpression of the Ras-activated Ral-GEF, Ral-GDS, largely potentiated RTK-mediated PLD stimulation, reaching PLD activity levels similar to that observed in cells stimulated with PMA. Based on these data, it is proposed that RTK-mediated PLD stimulation in HEK-293 cells is induced by two major signaling pathways known to be under control of such receptors (Fig. 8). First, by activation of phospholipase C-γ isoforms and, consequently, increased diacylglycerol production, PKC isoforms are activated by RTKs. Second, by activation of Ras-specific GEFs, such as SOS, via the adaptor protein Grb2, RTKs induce activation of Ras, which then in turn activates Ral-GEFs and, as a consequence, Ral proteins. Because PLD stimulation by the RTK agonists in control cells was clearly less than that induced by PMA but elevated to this level in cells overexpressing Ral-GDS, it may be concluded that activation of Ral proteins by RTKs is less efficient that than induced by PMA and, thus, is the limiting factor for RTK-mediated PLD stimulation in HEK-293 cells. It remains to be determined which of the ubiquitously expressed Ral-GEFs, Ral-GDS, Rgl, and Rlf (18Bos J.L. EMBO J. 1998; 17: 6776-6782Crossref PubMed Scopus (286) Google Scholar), specifically mediates RTK-induced activation of Ral proteins and PLD activity.Ras proteins can signal via several distinct effector pathways (18Bos J.L. EMBO J. 1998; 17: 6776-6782Crossref PubMed Scopus (286) Google Scholar, 21Voijtek A.B. Der C.J. J. Biol. Chem. 1998; 273: 19925-19928Abstract Full Text Full Text PDF PubMed Scopus (495) Google Scholar) and may also thereby regulate PLD activity. First, active Ras can stimulate production of phosphatidylinositol 3,4,5-trisphosphate by phosphoinositide 3-kinase. This polyphosphoinositide in turn has been shown to bind to and activate ARF-specific GEFs such as GRP-1 and ARNO both in vitro and in intact cells (35Klarlund J.K. Guilherme A. Holik J.J. Virbasius J.V. Chawla A. Czech M.P. Science. 1997; 275: 1927-1930Crossref PubMed Scopus (368) Google Scholar, 36Klarlund J.K. Rameh L.E. Cantley L.C. Buxton J.M. Holik J.J. Sakelis C. Patki V. Corvera S. Czech M.P. J. Biol. Chem. 1998; 273: 1859-1862Abstract Full Text Full Text PDF PubMed Scopus (146) Google Scholar, 37Venkateswarlu K. Oatey P.B. Tavaré J.M. Cullen P.J. Curr. Biol. 1998; 8: 463-466Abstract Full Text Full Text PDF PubMed Scopus (223) Google Scholar), thus leading to activation of PLD-stimulating ARF proteins. Accordingly, insulin has been reported to translocate ARNO to the plasma membrane in 3T3 L1 adipocytes in a phosphoinositide 3-kinase-dependent manner (37Venkateswarlu K. Oatey P.B. Tavaré J.M. Cullen P.J. Curr. Biol. 1998; 8: 463-466Abstract Full Text Full Text PDF PubMed Scopus (223) Google Scholar). Furthermore, insulin-induced PLD stimulation in rat adipocytes and Rat-1 fibroblasts overexpressing human insulin receptors has been shown to be mediated by ARF proteins and to involve phosphoinositide 3-kinase (38Standaert M.L. Avignon A. Yamada K. Bandyopadhyay G. Farese R.V. Biochem. J. 1996; 313: 1039-1046Crossref PubMed Scopus (60) Google Scholar, 39Karnam P. Standaert M.L. Galloway L. Farese R.V. J. Biol. Chem. 1997; 272: 6136-6140Abstract Full Text Full Text PDF PubMed Scopus (83) Google Scholar, 40Shome K. Vasudevan C. Romero G. Curr. Biol. 1997; 7: 387-396Abstract Full Text Full Text PDF PubMed Scopus (66) Google Scholar). However, treatment of HEK-293 cells with the phosphoinositide 3-kinase inhibitors LY294002 and wortmannin did not alter PMA- or RTK agonist-induced PLD stimulation (data not shown), whereas M3 mAChR-mediated PLD stimulation was fully blocked. 2M. Schmidt M. Voß, S. Bayer, M. Asmus, P. A. Oude Weernink, B. Lohmann, C. Rother, P. Chardin, B. Antonny, M. Amano, K. Kaibuchi, and K. H. Jakobs, submitted for publication. Another Ras effector pathway, possibly involved in Ras-dependent PLD activation, is the activation of PLD-stimulating Rho GTPases. Although the details of the putative Ras/Rac/Rho signaling pathway are not yet resolved, studies performed in Swiss 3T3 and Rat-1 fibroblasts indicated that Ras-induced stress fiber formation and transformation, respectively, is dependent on activation of Rho proteins (41Ridley A.J. Paterson H.F. Johnston C.L. Diekman D. Hall A. Cell. 1992; 70: 401-410Abstract Full Text PDF PubMed Scopus (3049) Google Scholar, 42Qiu R.-G. Chen J. McCormick F. Symons M. Proc. Natl. Acad. Sci. U. S. A. 1995; 92: 11781-11785Crossref PubMed Scopus (486) Google Scholar). Finally, active Ras stimulates the Raf-dependent MAP kinase pathway. In accordance, Frankel et al. (43Frankel P. Ramos M. Flom J. Bychenok S. Joseph T. Kerkhoff E. Rapp U.R. Feig L.A. Foster D.A. Biochem. Biophys. Res. Commun. 1999; 255: 502-507Crossref PubMed Scopus (48) Google Scholar) recently reported that in v-Raf-transformed NIH-3T3 cells PLD activity was increased. The increase in PLD activity induced by this Ras effector was blocked by coexpressing dominant-negative RalA or RhoC. Although it is presently unclear how Ral and Rho proteins are activated by v-Raf, the data suggest the existence of novel regulatory pathways involved in PLD activation. Alternatively, autocrine loops may exist and may be activated by v-Raf or Ras. However, in HEK-293 cells inactivation of Rho GTPases withC. difficile toxin B or blockade of MAP kinase activation by PD98059 did not affect PLD stimulation by PMA or RTK agonists, making it highly unlikely that these Ras effector pathways are involved in PKC- and RTK-induced PLD stimulation in these cells.The M3 mAChR expressed in HEK-293 cells mediates marked phospholipase C stimulation (10Schmidt M. Hüwe S.M. Fasselt B. Homann D. Rümenapp U. Sandmann J. Jakobs K.H. Eur. J. Biochem. 1994; 225: 667-675Crossref PubMed Scopus (88) Google Scholar). Nevertheless, PLD stimulation induced by this G protein-coupled receptor was not affected by inhibition or down-regulation of PKC or by expression of dominant-negative Ras and RalA mutants. From these data, it may be concluded that the M3 mAChR and the RTKs activate distinct PKC isoforms and/or distinct PLD enzymes. As PLD1 can interact with both Ral and PKC (15Luo J.-Q. Liu X. Hammond S.M. Colley W.C. Feig L.A. Frohman M.A. Morris A.J. Foster D.A. Biochem. Biophys. Res. Commun. 1997; 235: 854-859Crossref PubMed Scopus (79) Google Scholar,16Luo J.-Q. Liu X. Frankel P. Rotunda T. Ramos M. Flom J. Jiang H. Feig L.A. Morris A.J. Kahn R.A. Foster D.A. Proc. Natl. Acad. Sci. U. S. A. 1998; 95: 3632-3637Crossref PubMed Scopus (119) Google Scholar, 44Lee T.G. Park J.B. Lee S.D. Hong S. Kim J.H. Kim Y. Yi K.S. Bae S. Hannun Y.A. Obeid L.M. Suh P.-G. Ryu S.H. Biochim. Biophys. Acta. 1997; 1347: 199-204Crossref PubMed Scopus (65) Google Scholar, 45Park S.-K. Min D.S. Exton J.H. Biochem. Biophys. Res. Commun. 1998; 244: 364-367Crossref PubMed Scopus (54) Google Scholar, 46Min D.S. Exton J.H. Biochem. Biophys. Res. Commun. 1998; 248: 533-537Crossref PubMed Scopus (30) Google Scholar), this PLD isoform could be the species involved in RTK-mediated PLD stimulation in HEK-293 cells. On the other hand, by expressing catalytically inactive variants of PLD1 and PLD2, evidence has recently been provided that the insulin-induced PLD stimulation in Rat-1 fibroblasts, which is mediated by ARF proteins, specifically involves PLD2 (47Rizzo M.A. Shome K. Vasudevan C. Stolz D.B. Sung T.-C. Frohman M.A. Watkins S.C. Romero G. J. Biol. Chem. 1999; 274: 1131-1139Abstract Full Text Full Text PDF PubMed Scopus (267) Google Scholar). Furthermore, by overexpressing PLD1 and PLD2 together with the EGF receptor in HEK-293 cells, Slaaby et al. (30Slaaby R. Jensen T. Hansen H.S. Frohman M.A. Seedorf K. J. Biol. Chem. 1998; 273: 33722-33727Abstract Full Text Full Text PDF PubMed Scopus (102) Google Scholar) recently reported that EGF can activate both PLD1 and PLD2 enzymes and that PLD2 associates with the EGF receptor in a ligand-independent manner and becomes tyrosine-phosphorylated upon EGF receptor activation. Thus, both PLD enzymes can apparently be activated following receptor activation. Which of the PLD isoforms, PLD1 and/or PLD2, is activated by the M3 mAChR and the RTKs in HEK-293 cells is presently under investigation.In summary, our study indicates the existence of a Ras/Ral-GEF/Ral signaling cascade involved in PLD stimulation by PKC in HEK-293 cells. Furthermore, and most important, strong evidence is provided that PLD stimulation by EGF, PDGF, and insulin receptors is mediated by a concerted action of PKC and Ras/Ral-GEF-activated Ral proteins. Phospholipase D (PLD)1catalyzes formation of phosphatidic acid from the major membrane phospholipid, phosphatidylcholine (PtdCho), and this reaction is implicated in the regulation of diverse cellular processes, such as vesicular trafficking and cell growth and differentiation. A large variety of receptor tyrosine kinases (RTKs) and receptors coupled to heterotrimeric G proteins in a wide range of cell types has been reported to mediate PLD stimulation in response to their specific agonists. However, the mechanisms of receptor signaling to PLD in intact cells are only poorly understood and seem to involve distinct signal transduction components, in particular different small GTPases and protein kinase C (PKC) isoforms (for reviews, see Refs. 1Exton J.H. J. Biol. Chem. 1997; 272: 15579-15582Abstract Full Text Full Text PDF PubMed Scopus (284) Google Scholar, 2Singer W.D. Brown H.A. Sternweis P.C. Annu. Rev. Biochem. 1997; 66: 475-509Crossref PubMed Scopus (347) Google Scholar, 3Cockcroft S. Prog. Lipid Res. 1997; 35: 345-370Crossref Scopus (55) Google Scholar, 4Morris A.J. Engebrecht J. Frohman M.A. Trends Biochem. Sci. 1996; 17: 182-185Scopus (175) Google Scholar, 5Exton J.H. Physiol. Rev. 1997; 77: 303-320Crossref PubMed Scopus (386) Google Scholar). In HEK-293 cells, stably expressing the M3 muscarinic acetylcholine receptor (mAChR), GTPases of distinct families, such as ADP-ribosylation factor (ARF), Rho, and Ral, as well as various protein kinases, such as PKC, Rho kinase, and tyrosine kinases, apparently mediate PLD activation. Specifically, stimulation of PLD by the G protein-coupled M3 mAChR is dependent on ARF and Rho GTPases and apparently involves a tyrosine kinase and Rho kinase but not PKC. On the other hand, PLD stimulation by phorbol ester-activated PKC, which is phosphorylation-dependent in HEK-293 cells, is apparently ARF-independent and only poorly inhibited by inactivation of Rho proteins (6Rümenapp U. Geiszt M. Friederike W. Schmidt M. Jakobs K.H. Eur. J. Biochem. 1995; 324: 240-244Crossref Scopus (81) Google Scholar, 7Schmidt M. Rümenapp U. Bienek C. Keller J. von Eichel-Streiber C. Jakobs K.H. J. Biol. Chem. 1996; 271: 2422-2426Abstract Full Text Full Text PDF PubMed Scopus (107) Google Scholar, 8Schürmann A. Schmidt M. Asmus M. Bayer S. Fliegert F. Kolin S. Maßmann S. Schilf C. Subauste M.C. Voß M. Jakobs K.H. Joost H.-G. J. Biol. Chem. 1999; 274: 9744-9751Abstract Full Text Full Text PDF PubMed Scopus (27) Google Scholar, 9Schmidt M. Voß M. Oude Weernink P.A. Wetzel J. Amano M. Kaibuchi K. Jakobs K.H. J. Biol. Chem. 1999; 274: 14648-14654Abstract Full Text Full Text PDF PubMed Scopus (76) Google Scholar, 10Schmidt M. Hüwe S.M. Fasselt B. Homann D. Rümenapp U. Sandmann J. Jakobs K.H. Eur. J. Biochem. 1994; 225: 667-675Crossref PubMed Scopus (88) Google Scholar, 11Rümenapp U. Schmidt M. Wahn F. Tapp E. Grannass A. Jakobs K.H. Eur. J. Biochem. 1997; 248: 407-414Crossref PubMed Scopus (23) Google Scholar). Recently, evidence has been provided that Ral GTPases are involved in PKC-induced PLD stimulation in HEK-293 cells (12Schmidt M. Voß M. Thiel M. Bauer B. Grannaß A. Tapp E. Cool R.H. de Gunzburg J. von Eichel-Streiber C. Jakobs K.H. J. Biol. Chem. 1998; 273: 7413-7422Abstract Full Text Full Text PDF PubMed Scopus (54) Google Scholar). Previously, Ral GTPases have been reported to be involved in Ras-mediated PLD activation in v-Src-transformed Balb/c- and NIH-3T3 fibroblasts (13Jiang H. Lu Z. Luo J.-Q. Wolfman A. Foster D.A. J. Biol. Chem. 1995; 270: 6006-6009Abstract Full Text Full Text PDF PubMed Scopus (86) Google Scholar, 14Jiang H. Luo J.-Q. Urano T. Frankel P. Lu Z. Foster D.A. Feig L.A. Nature. 1995; 378: 409-412Crossref PubMed Scopus (246) Google Scholar). Moreover, RalA has re" @default.
W2017996683 created "2016-06-24" @default.
W2017996683 creator A5003127241 @default.
W2017996683 creator A5008047411 @default.
W2017996683 creator A5014919267 @default.
W2017996683 creator A5017965104 @default.
W2017996683 creator A5034910981 @default.
W2017996683 creator A5052754373 @default.
W2017996683 creator A5059726330 @default.
W2017996683 creator A5062713669 @default.
W2017996683 creator A5084201060 @default.
W2017996683 date "1999-12-01" @default.
W2017996683 modified "2023-09-30" @default.
W2017996683 title "Phospholipase D Stimulation by Receptor Tyrosine Kinases Mediated by Protein Kinase C and a Ras/Ral Signaling Cascade" @default.
W2017996683 cites W1796314406 @default.
W2017996683 cites W1832453319 @default.
W2017996683 cites W1926696092 @default.
W2017996683 cites W1971747715 @default.
W2017996683 cites W1973770590 @default.
W2017996683 cites W1973834617 @default.
W2017996683 cites W1976331372 @default.
W2017996683 cites W1983011848 @default.
W2017996683 cites W1983651221 @default.
W2017996683 cites W2000816990 @default.
W2017996683 cites W2001895687 @default.
W2017996683 cites W2007375100 @default.
W2017996683 cites W2008346251 @default.
W2017996683 cites W2009235369 @default.
W2017996683 cites W2011774111 @default.
W2017996683 cites W2016515552 @default.
W2017996683 cites W2016955301 @default.
W2017996683 cites W2017550542 @default.
W2017996683 cites W2018149384 @default.
W2017996683 cites W2025868935 @default.
W2017996683 cites W2026844414 @default.
W2017996683 cites W2029149519 @default.
W2017996683 cites W2039185825 @default.
W2017996683 cites W2039740105 @default.
W2017996683 cites W2046618378 @default.
W2017996683 cites W2054379164 @default.
W2017996683 cites W2058795586 @default.
W2017996683 cites W2059986736 @default.
W2017996683 cites W2063975035 @default.
W2017996683 cites W2066791280 @default.
W2017996683 cites W2067889127 @default.
W2017996683 cites W2069261043 @default.
W2017996683 cites W2070992726 @default.
W2017996683 cites W2075242575 @default.
W2017996683 cites W2076311524 @default.
W2017996683 cites W2078613588 @default.
W2017996683 cites W2079675328 @default.
W2017996683 cites W2080731964 @default.
W2017996683 cites W2093226717 @default.
W2017996683 cites W2103811827 @default.
W2017996683 cites W2112919363 @default.
W2017996683 cites W2156875265 @default.
W2017996683 cites W2156967607 @default.
W2017996683 cites W2313522156 @default.
W2017996683 doi "https://doi.org/10.1074/jbc.274.49.34691" @default.
W2017996683 hasPubMedId "https://pubmed.ncbi.nlm.nih.gov/10574935" @default.
W2017996683 hasPublicationYear "1999" @default.
W2017996683 type Work @default.
W2017996683 sameAs 2017996683 @default.
W2017996683 citedByCount "66" @default.
W2017996683 countsByYear W20179966832013 @default.
W2017996683 countsByYear W20179966832014 @default.
W2017996683 countsByYear W20179966832017 @default.
W2017996683 countsByYear W20179966832018 @default.
W2017996683 countsByYear W20179966832019 @default.
W2017996683 crossrefType "journal-article" @default.
W2017996683 hasAuthorship W2017996683A5003127241 @default.
W2017996683 hasAuthorship W2017996683A5008047411 @default.
W2017996683 hasAuthorship W2017996683A5014919267 @default.
W2017996683 hasAuthorship W2017996683A5017965104 @default.
W2017996683 hasAuthorship W2017996683A5034910981 @default.
W2017996683 hasAuthorship W2017996683A5052754373 @default.
W2017996683 hasAuthorship W2017996683A5059726330 @default.
W2017996683 hasAuthorship W2017996683A5062713669 @default.
W2017996683 hasAuthorship W2017996683A5084201060 @default.
W2017996683 hasBestOaLocation W20179966831 @default.
W2017996683 hasConcept C101544691 @default.
W2017996683 hasConcept C134018914 @default.
W2017996683 hasConcept C184235292 @default.
W2017996683 hasConcept C185592680 @default.
W2017996683 hasConcept C24998067 @default.
W2017996683 hasConcept C2778597717 @default.
W2017996683 hasConcept C42362537 @default.
W2017996683 hasConcept C55493867 @default.
W2017996683 hasConcept C62478195 @default.
W2017996683 hasConcept C86803240 @default.
W2017996683 hasConcept C95444343 @default.
W2017996683 hasConceptScore W2017996683C101544691 @default.
W2017996683 hasConceptScore W2017996683C134018914 @default.
W2017996683 hasConceptScore W2017996683C184235292 @default.
W2017996683 hasConceptScore W2017996683C185592680 @default.
W2017996683 hasConceptScore W2017996683C24998067 @default.
W2017996683 hasConceptScore W2017996683C2778597717 @default.
W2017996683 hasConceptScore W2017996683C42362537 @default.