SemOpenAlex |

SemOpenAlex

Matches in SemOpenAlex for { <https://semopenalex.org/work/W2026748045> ?p ?o ?g. }

Showing items 1 to 100 of ±138 with 100 items per page.

W2026748045 endingPage "30644" @default.
W2026748045 startingPage "30637" @default.
W2026748045 abstract "The small GTPase RhoB is immediate-early inducible by DNA damaging treatments and thus part of the early response of eukaryotic cells to genotoxic stress. To investigate the regulation of this cellular response, we isolated the gene forrhoB from a mouse genomic library. Sequence analysis of therhoB gene showed that its coding region does not contain introns. The promoter region of rhoB harbors regulatory elements such as TATA, CAAT, and Sp1 boxes but not consensus sequences for AP-1, Elk-1, or c-Jun/ATF-2. The rhoB promoter was activated by UV irradiation, but not by 12-O-tetradecanoylphorbol-13-acetate treatment.rhoB promoter deletion constructs revealed a fragment of 0.17 kilobases in size which was sufficient in eliciting the UV response. This minimal promoter fragment contains TATA and CAAT boxes but no other known regulatory elements. Neither MEK inhibitor PD98059 nor p38 kinase inhibitor SB203580 blocked stimulation ofrhoB by UVC (UV light, 254 nm) which indicates that ERK or p38 mitogen-activated protein (MAP) kinase are not involved in the UV induction of rhoB. Also, phosphatidylinositol 3-kinase inhibitor wortmannin, which blocks UV stimulation of both JNK and p38 MAP kinase, did not inhibit rhoB activation. Furthermore, activation of JNK by interleukin-1β did not affect rhoBexpression. These data indicate that JNK is not involved in the regulation of rhoB. Overexpression of wild-type Rac as well as the Rho guanine-dissociation inhibitor caused activation ofrhoB. Wild-type RhoB inhibited both basal and UV-stimulatedrhoB promoter activity, indicating a negative regulatory feedback by RhoB itself. The data provide evidence both for a signal transduction pathway independent of JNK, ERK, and p38 MAP kinase to be involved in the induction of rhoB by genotoxic stress, and furthermore, indicate autoregulation of rhoB. The small GTPase RhoB is immediate-early inducible by DNA damaging treatments and thus part of the early response of eukaryotic cells to genotoxic stress. To investigate the regulation of this cellular response, we isolated the gene forrhoB from a mouse genomic library. Sequence analysis of therhoB gene showed that its coding region does not contain introns. The promoter region of rhoB harbors regulatory elements such as TATA, CAAT, and Sp1 boxes but not consensus sequences for AP-1, Elk-1, or c-Jun/ATF-2. The rhoB promoter was activated by UV irradiation, but not by 12-O-tetradecanoylphorbol-13-acetate treatment.rhoB promoter deletion constructs revealed a fragment of 0.17 kilobases in size which was sufficient in eliciting the UV response. This minimal promoter fragment contains TATA and CAAT boxes but no other known regulatory elements. Neither MEK inhibitor PD98059 nor p38 kinase inhibitor SB203580 blocked stimulation ofrhoB by UVC (UV light, 254 nm) which indicates that ERK or p38 mitogen-activated protein (MAP) kinase are not involved in the UV induction of rhoB. Also, phosphatidylinositol 3-kinase inhibitor wortmannin, which blocks UV stimulation of both JNK and p38 MAP kinase, did not inhibit rhoB activation. Furthermore, activation of JNK by interleukin-1β did not affect rhoBexpression. These data indicate that JNK is not involved in the regulation of rhoB. Overexpression of wild-type Rac as well as the Rho guanine-dissociation inhibitor caused activation ofrhoB. Wild-type RhoB inhibited both basal and UV-stimulatedrhoB promoter activity, indicating a negative regulatory feedback by RhoB itself. The data provide evidence both for a signal transduction pathway independent of JNK, ERK, and p38 MAP kinase to be involved in the induction of rhoB by genotoxic stress, and furthermore, indicate autoregulation of rhoB. The Rho subfamily of small GTP-binding proteins play an important regulatory role in diverse cellular functions, including endocytosis (1Schmalzing G. Richter H.P. Hansen A. Schwarz W. Just I. Aktories K. J. Cell Biol. 1995; 130: 1319-1332Crossref PubMed Scopus (96) Google Scholar), membrane ruffling (2Ridley A.J. Paterson H.F. Johnston C.L. Diekmann D. Hall A. Cell. 1992; 70: 401-410Abstract Full Text PDF PubMed Scopus (3050) Google Scholar, 3Michiels F. Habets G.G. Stam J.C. van-der-Kammen R.A. Collard J.G. Nature. 1995; 375: 338-340Crossref PubMed Scopus (506) Google Scholar), cell cycle progress (4Olson M.F. Ashworth A. Hall A. Science. 1995; 269: 1270-1272Crossref PubMed Scopus (1055) Google Scholar), transformation (5Qiu R.-G. Chen J. Kirn D. McCormick F. Symons M. Nature. 1995; 374: 457-459Crossref PubMed Scopus (812) Google Scholar, 6Prendergast G.C. Khosravi-Far R. Solski P.A. Kurzawa H. Lebowitz P.F. Der C.J. Oncogene. 1995; 10: 2289-2296PubMed Google Scholar), and the organization of the cytoskeleton (7Ridley A.J. Hall A. Cell. 1992; 70: 389-399Abstract Full Text PDF PubMed Scopus (3797) Google Scholar, 8Paterson H.F. Self A.J. Garrett M.D. Just I. Aktories K. Hall A. J. Cell Biol. 1990; 11: 1001-1007Crossref Scopus (567) Google Scholar, 9Wiegers W. Just I. Müller H.M. Hellwig A. Traub P. Aktories K. Eur. J. Cell Biol. 1991; 54: 237-245PubMed Google Scholar, 10Hall A. Mol. Cell. Biol. 1992; 3: 475-479Crossref Scopus (173) Google Scholar). Recently the small GTPases Rac and Cdc42 have been shown to selectively activate c-Jun N-terminal kinase (JNK) signaling without affecting MAP kinase (MAPK), 1The abbreviations used are: MAPK, mitogen-activated protein kinase; IL-1, interleukin-1; TNF-α, tumor necrosis factor-α; PI 3-kinase, phosphatidylinositol 3-kinase; kb, kilobase(s); PCR, polymerase chain reaction; TPA, 12-O-tetradecanoylphorbol-13-acetate; CAT, chloramphenicol acetyltransferase; bp, base pair(s); INF-γ, interferon-γ; GDI, guanine-dissociation inhibitor; UVC, UV light (254 nm). 1The abbreviations used are: MAPK, mitogen-activated protein kinase; IL-1, interleukin-1; TNF-α, tumor necrosis factor-α; PI 3-kinase, phosphatidylinositol 3-kinase; kb, kilobase(s); PCR, polymerase chain reaction; TPA, 12-O-tetradecanoylphorbol-13-acetate; CAT, chloramphenicol acetyltransferase; bp, base pair(s); INF-γ, interferon-γ; GDI, guanine-dissociation inhibitor; UVC, UV light (254 nm). whereas RhoA does not act on JNK nor MAPK (11Minden A. Lin A. Claret F.-X. Abo A. Karin M. Cell. 1995; 81: 1147-1157Abstract Full Text PDF PubMed Scopus (1444) Google Scholar, 12Hill C.S. Wynne J. Treisman R. Cell. 1995; 81: 1159-1170Abstract Full Text PDF PubMed Scopus (1199) Google Scholar, 13Coso A.A. Chiariello M. Yu J.-C. Teramoto H. Crespo P. Xu N. Miki T. Gutkind J.S. Cell. 1995; 81: 1137-1146Abstract Full Text PDF PubMed Scopus (1559) Google Scholar). JNK represents a family of closely related enzymes which are activated by cellular stress; they are therefore also named as stress-activated protein kinases (p46/p54 SAPK) (14Kyriakis J.M. Banerjee P. Nikolakaki E. Dai T. Rubie E.A. Ahmad M.F. Avruch J. Woodgett J.R. Nature. 1994; 369: 156-160Crossref PubMed Scopus (2408) Google Scholar, 15Derijard B. Hibi M. Wu I.H. Barrett T. Deng T. Karin M. Davis R.J. Cell. 1994; 76: 1025-1037Abstract Full Text PDF PubMed Scopus (2949) Google Scholar). JNK activity is strongly stimulated by inhibitors of protein biosynthesis, such as cycloheximide and anisomycin, by inflammatory cytokines such as TNF-α and IL-1 and by ultraviolet (UV) light or other DNA-damaging agents (14Kyriakis J.M. Banerjee P. Nikolakaki E. Dai T. Rubie E.A. Ahmad M.F. Avruch J. Woodgett J.R. Nature. 1994; 369: 156-160Crossref PubMed Scopus (2408) Google Scholar, 15Derijard B. Hibi M. Wu I.H. Barrett T. Deng T. Karin M. Davis R.J. Cell. 1994; 76: 1025-1037Abstract Full Text PDF PubMed Scopus (2949) Google Scholar, 16Coso O.A. Chiariello M. Kalinec G. Kyriakis J.M. Woodgett J. Gutkind J.S. J. Biol. Chem. 1995; 270: 5620-5624Abstract Full Text Full Text PDF PubMed Scopus (209) Google Scholar). Activated JNKs are thought to phosphorylate the transactivation domain of c-Jun, thereby strongly increasing the transactivating activity of AP-1. This is the way the expression of various AP-1 dependent genes, including c-junitself, is controlled (17Angel P. Bhattari K. Smeal T. Karin M. Cell. 1988; 55: 875-885Abstract Full Text PDF PubMed Scopus (986) Google Scholar).Recently, it turned out that JNK-dependent phosphorylation of ATF-2, which can dimerize with c-Jun, is the major mechanism mediating c-jun induction upon genotoxic stress (18van Dam H. Wilhelm D. Herr I. Steffen A. Herrlich P. Angel P. EMBO J. 1995; 14: 1798-1811Crossref PubMed Scopus (569) Google Scholar). The finding that UV-induced expression of c-fos is regulated by JNK-mediated phosphorylation of TCF/Elk-1 (19Cavigelli M. Dolfi F. Claret F.-X. Karin M. EMBO J. 1995; 14: 5957-5964Crossref PubMed Scopus (485) Google Scholar) indicates a central role of JNK (stress-activated protein kinases) in the regulation of DNA damage-induced expression of the immediate-early genes c-junand c-fos. It has been supposed that the protein kinase phosphorylating c-Jun in response to TPA treatment is distinct from JNK and does not act on ATF-2 (18van Dam H. Wilhelm D. Herr I. Steffen A. Herrlich P. Angel P. EMBO J. 1995; 14: 1798-1811Crossref PubMed Scopus (569) Google Scholar). Another important mechanism involved in the regulation of early mammalian responses to genotoxic stress is based on the activation of tyrosine kinases, c-Ha-ras and MAPK (20Sachsenmaier C. Radler-Pohl A. Zinck R. Nordheim A. Herrlich P. Rahmsdorf H.J. Cell. 1994; 78: 963-972Abstract Full Text PDF PubMed Scopus (406) Google Scholar,21Devary Y. Gottlieb R.A. Smeal T. Karin M. Cell. 1992; 71: 1081-1091Abstract Full Text PDF PubMed Scopus (795) Google Scholar). Since overexpression of activated Ha-Ras elicits JNK activity (15Derijard B. Hibi M. Wu I.H. Barrett T. Deng T. Karin M. Davis R.J. Cell. 1994; 76: 1025-1037Abstract Full Text PDF PubMed Scopus (2949) Google Scholar), a cross-talk between JNK and MAPK signaling appears to be possible. JNK are not activated by TPA, and to a much lesser extent by growth factors than ERK1/2 (14Kyriakis J.M. Banerjee P. Nikolakaki E. Dai T. Rubie E.A. Ahmad M.F. Avruch J. Woodgett J.R. Nature. 1994; 369: 156-160Crossref PubMed Scopus (2408) Google Scholar, 16Coso O.A. Chiariello M. Kalinec G. Kyriakis J.M. Woodgett J. Gutkind J.S. J. Biol. Chem. 1995; 270: 5620-5624Abstract Full Text Full Text PDF PubMed Scopus (209) Google Scholar). Furthermore, induction of c-fos and c-jun by inhibitors of protein biosynthesis is thought to be mainly due to the activation of JNK (22Cano E. Hazzalin C.A. Mahadevan L.C. Mol. Cell. Biol. 1994; 14: 7352-7362Crossref PubMed Scopus (268) Google Scholar,23Zinck R. Cahill M.A. Kracht M. Sachsenmaier C. Hipskind R.A. Nordheim A. Mol. Cell. Biol. 1995; 15: 4930-4938Crossref PubMed Scopus (236) Google Scholar). Recently it was shown that, beside JNK and ERK, p38 MAP kinase cascade also interferes with stress-induced signaling (24Wang X.Z. Ron D. Science. 1996; 272: 1347-1349Crossref PubMed Scopus (738) Google Scholar, 25Stein B. Brady H. Yang M.X. Young D.B. Barbosa M.S. J. Biol. Chem. 1996; 271: 11427-11433Abstract Full Text Full Text PDF PubMed Scopus (158) Google Scholar, 26Moriguchi T. Kuroyanagi N. Yamaguchi K. Gotoh Y. Irie k. Kano T. Shirakabe K. Muro Y. Shibuya H. Matsumoto K. Nishida E. Hagiwara M. J. Biol. Chem. 1996; 271: 13675-13679Abstract Full Text Full Text PDF PubMed Scopus (406) Google Scholar, 27Landry J. Huot J. Biochem. Cell Biol. 1995; 73: 703-707Crossref PubMed Scopus (231) Google Scholar). This signaling pathway can also be stimulated by Cdc42 and Rac (28Zhang S. Han J. Sells M.A. Chernoff J. Knaus U.G. Ulevitch R.J. Bokoch G.M. J. Biol. Chem. 1995; 270: 23934-23936Abstract Full Text Full Text PDF PubMed Scopus (651) Google Scholar, 29Bagrodia S. Derijard B. Davis R.J. Cerione R.A. J. Biol. Chem. 1995; 270: 27995-27998Abstract Full Text Full Text PDF PubMed Scopus (598) Google Scholar).RhoB, which belongs to the Rho family of small GTPases is, similar to c-fos and c-jun, very rapidly inducible by DNA damaging treatments (30Fritz G. Kaina B. Aktories K. J. Biol. Chem. 1995; 270: 25172-25177Abstract Full Text Full Text PDF PubMed Scopus (138) Google Scholar). RhoB distinguishes from other Rho species (e.g. RhoA and RhoC) in its inducibility by both growth factors and DNA damaging agents, such as UV light and alkylating agents (30Fritz G. Kaina B. Aktories K. J. Biol. Chem. 1995; 270: 25172-25177Abstract Full Text Full Text PDF PubMed Scopus (138) Google Scholar, 31Jähner D. Hunter T. Mol. Cell. Biol. 1991; 11: 3682-3690Crossref PubMed Scopus (151) Google Scholar), as well as by its intracellular localization (32Adamson P. Paterson H.F. Hall A. J. Cell Biol. 1992; 119: 617-627Crossref PubMed Scopus (327) Google Scholar). Thus, the physiological function of RhoB appears to be different from RhoA and RhoC which are thought to function mainly in the regulation of the actin cytoskeleton (10Hall A. Mol. Cell. Biol. 1992; 3: 475-479Crossref Scopus (173) Google Scholar). Similar to c-fos and c-jun, the amount of rhoB mRNA is very rapidly enhanced after treatment of cells with cycloheximide, growth factors, and genotoxic agents. However, in contrast to c-fosand c-jun, the phorbol ester TPA did not elicit increase inrhoB mRNA expression (30Fritz G. Kaina B. Aktories K. J. Biol. Chem. 1995; 270: 25172-25177Abstract Full Text Full Text PDF PubMed Scopus (138) Google Scholar, 31Jähner D. Hunter T. Mol. Cell. Biol. 1991; 11: 3682-3690Crossref PubMed Scopus (151) Google Scholar). This lack of TPA response prompted us to hypothesize that the regulation of rhoBexpression is different from that of c-jun and c-fos.In the present study, we aimed at elucidating the regulation ofrhoB on the level of the promoter. Having cloned the mouse gene for rhoB and analyzed its promoter region, we demonstrate that rhoB promoter activity is autoregulated by small GTPases of the Rho family. Furthermore, based on sequence data as well as inhibitor studies, we suggest a signal transduction pathway which is independent from JNK, ERK, and p38 MAP kinase to be involved in the UV stimulation of the rhoB promoter.DISCUSSIONExposure of eukaryotic cells to genotoxic agents induces a variety of responses including the activation of cellular growth factor receptors and Src tyrosine kinases (20Sachsenmaier C. Radler-Pohl A. Zinck R. Nordheim A. Herrlich P. Rahmsdorf H.J. Cell. 1994; 78: 963-972Abstract Full Text PDF PubMed Scopus (406) Google Scholar, 21Devary Y. Gottlieb R.A. Smeal T. Karin M. Cell. 1992; 71: 1081-1091Abstract Full Text PDF PubMed Scopus (795) Google Scholar, 50Miller C.C. Hale P. Pentland P.A. J. Biol. Chem. 1994; 269: 3529-3533Abstract Full Text PDF PubMed Google Scholar), the accumulation of p53 and subsequent blockage in cell cycle progression (51Fritsche M. Haessler C. Brandner G. Oncogene. 1993; 8: 307-318PubMed Google Scholar, 52Lu X. Lane D.P. Cell. 1993; 75: 765-778Abstract Full Text PDF PubMed Scopus (773) Google Scholar, 53Xiong Y. Hannon G.Y. Zhang H. Casso D. Kobayashi R. Beach D. Nature. 1993; 366: 701-704Crossref PubMed Scopus (3157) Google Scholar, 54Dulic V. Kaufmann W.K. Wilson S.J. Tlsty T.D. Lees S. Harper J.W. Elledge S.J. Reed S.I. Cell. 1994; 76: 1013-1023Abstract Full Text PDF PubMed Scopus (1414) Google Scholar, 55El-Deiry W.S. Tokino T. Velculescu V.E. Levy D.B. Parsons R. Trent J.M. Lin D. Mercer W.E. Kinzler K.W. Vogelstein B. Cell. 1993; 75: 817-825Abstract Full Text PDF PubMed Scopus (7890) Google Scholar), and the transcriptional activation of a variety of genes (56Kaina B. Stein B. Schönthal A. Rahmsdorf H.J. Ponta H. Herrlich P. Lambert M.W. Laval J. DNA Repair Mechanisms and Their Biological Implications in Mammalian Cells. Plenum Publishing Corp., New York1990: 149-165Google Scholar, 57Herrlich P. Ponta H. Rahmsdorf H.J. Rev. Physiol. Biochem. Pharmacol. 1992; 119: 187-212Crossref PubMed Scopus (182) Google Scholar). Among the DNA damage inducible genes, most interest has focused on the immediate-early genes c-fos and c-jun. It is believed that both the receptor mediated activation of MAPK (20Sachsenmaier C. Radler-Pohl A. Zinck R. Nordheim A. Herrlich P. Rahmsdorf H.J. Cell. 1994; 78: 963-972Abstract Full Text PDF PubMed Scopus (406) Google Scholar, 21Devary Y. Gottlieb R.A. Smeal T. Karin M. Cell. 1992; 71: 1081-1091Abstract Full Text PDF PubMed Scopus (795) Google Scholar,58Devary Y. Gottlieb R.A. Lau L.F. Karin M. Mol. Cell. Biol. 1991; 11: 2804-2811Crossref PubMed Scopus (597) Google Scholar) and Rac/Cdc42-mediated activation of JNK participate in the regulation of these genes (19Cavigelli M. Dolfi F. Claret F.-X. Karin M. EMBO J. 1995; 14: 5957-5964Crossref PubMed Scopus (485) Google Scholar, 59Hill C.S. Treisman R. Cell. 1995; 80: 201-211Abstract Full Text PDF Scopus (1195) Google Scholar). The induction of therhoB gene, which codes for a Ras-related small GTPase, is another very early event after exposure of cells to DNA damaging agents (30Fritz G. Kaina B. Aktories K. J. Biol. Chem. 1995; 270: 25172-25177Abstract Full Text Full Text PDF PubMed Scopus (138) Google Scholar). Induction of RhoB appears to be of particular interest because GTP-binding proteins can induce changes in the activity of their downstream targets very rapidly. Thus they may quickly trigger subsequent responses which are supposed to be protective. In contrast to c-fos and c-jun, rhoB expression is not stimulated by the phorbol ester TPA (30Fritz G. Kaina B. Aktories K. J. Biol. Chem. 1995; 270: 25172-25177Abstract Full Text Full Text PDF PubMed Scopus (138) Google Scholar, 31Jähner D. Hunter T. Mol. Cell. Biol. 1991; 11: 3682-3690Crossref PubMed Scopus (151) Google Scholar) which indicates that different signal transduction pathways are involved in the regulation of these immediate-early genes. In this study, we aimed at elucidating mechanisms controlling rhoB expression.To this end, we cloned and analyzed the promoter of the mouserhoB gene. We demonstrate here that the activity of the rhoB promoter was stimulated by genotoxic treatments such as UVC, methyl methanesulfonate, and hydrogen peroxide. The sequence data obtained revealed that the rhoB promoter contains TATA, Sp1, and CAAT box elements as well as consensus sequences for AP-2, AP-4, and p53. Interestingly, consensus sequences for known, UV-activated transcription factors (e.g. AP-1, c-Jun/ATF-2, Elk-1, or CHOP (gadd153)) were not present within the rhoB promoter. Generation of a set of rhoB promoter deletion constructs let us to identify a 0.17-kb rhoB promoter fragment which still retained activator activity upon UV irradiation. Furthermore, this fragment was also subject of stimulation by coexpression of Rac and inhibition by coexpression of RhoB to a similar extend as the original 3.5-kb fragment. Thus we suggest that the regulatory elements required for both positive and negative regulation of rhoB are located within this minimal 0.17-kb rhoB promoter fragment. With the exception of the CAAT and TATA box, the 0.17-kb fragment lacks any binding site for known transcription factors. As indicated by the data obtained from sequence and deletion analysis, two mediators of the UV response, namely AP-1 and p53, appear not to be involved inrhoB regulation. This hypothesis is supported by the finding that cells deficient in either c-fos or p53responded in the same way as wild-type cells do with regard to the extent of UV-induced increase in the amount of rhoB mRNA (data not shown). Thus, our data give evidence for the existence of a novel regulatory element within the rhoB promoter, mediating UV induction according to a yet not described mechanism.To address the question of what kind of signaling might be involved inrhoB induction, we analyzed the effect of overexpression of various small GTPases of the Rho family, which have been shown to participate in genotoxic stress signaling (11Minden A. Lin A. Claret F.-X. Abo A. Karin M. Cell. 1995; 81: 1147-1157Abstract Full Text PDF PubMed Scopus (1444) Google Scholar, 13Coso A.A. Chiariello M. Yu J.-C. Teramoto H. Crespo P. Xu N. Miki T. Gutkind J.S. Cell. 1995; 81: 1137-1146Abstract Full Text PDF PubMed Scopus (1559) Google Scholar), on the activity of the rhoB promoter. Interestingly, overexpression of wild-type Rac was sufficient to strongly stimulate rhoBpromoter, whereas wild-type Cdc42 had no effect. As might have been expected, V12Rac exerted a stronger stimulatory effect onrhoB than the wild-type form did. However, even the use of V12Cdc42 did not elicit rhoB promoter activity. Thus, although Rac and Cdc42 share the same signaling activities in respect to activation of JNK and p38 MAP kinase, they obviously distinguish from each other in respect to rhoB regulation. Notably, despite their identical signaling activities on JNK and p38, different physiological activities of Rac and Cdc42 have also been described. For example, Rac has been demonstrated to be involved in the formation of lamellipodia, whereas Cdc42 interferes with the generation of filopodia (60Nobes C.D. Hall A. Cell. 1995; 81: 53-62Abstract Full Text PDF PubMed Scopus (3700) Google Scholar). Furthermore, TNF-α-dependent activation of NF-κB is reported to depend on Cdc42 but not on Rac (61Perona R. Montaner S. Saniger L. Sanchez-Perez I. Bravo R. Lacal J.C. Genes Dev. 1997; 11: 463-475Crossref PubMed Scopus (532) Google Scholar). These reports agree with our data in that they clearly show the involvement of Rac and Cdc42 also in different signaling pathways. Although JNK and p38 kinase are known as important kinases in stress-induced signaling, it appears unlikely that these kinases are involved in rhoB regulation because of the following reasons. (i) As mentioned above, no target sequences for transcription factors regulated by these kinases (e.g. c-Jun, ATF-2, Elk-1, and CHOP) were detected within the rhoB promoter. (ii) Inhibition of PI 3-kinase by wortmannin rather blocked UV-mediated activation of JNK and p38 kinase but did not affect UV response of rhoB. (iii) IL-1β rather activated JNK but failed to increase rhoB expression. (iv) p38 inhibitor SB203580 did not inhibit UV stimulation ofrhoB and (v) wild-type Rac is sufficient to activaterhoB but even V12Cdc42 fails to do so. Bearing in mind that TPA is unable to increase rhoB expression and that the MEK inhibitor PD98059 did not block UV stimulation of rhoB, it further appears that ERK also do not participate in rhoBregulation upon UV irradiation. The observation that down-modulation of signaling by TPA pretreatment results in a partial block of UV-inducedrhoB mRNA expression (30Fritz G. Kaina B. Aktories K. J. Biol. Chem. 1995; 270: 25172-25177Abstract Full Text Full Text PDF PubMed Scopus (138) Google Scholar) and also rhoBpromoter activity (data not shown) does not contradict this hypothesis because TPA induced PKC signaling is not limited to ERK. Furthermore, the finding that INF-γ failed to increase rhoB expression may be taken as an indication that JAK's, which are generally activated by INF-γ, are also not involved in rhoBexpression.A further interesting feature of rhoB regulation is its negative feedback regulation by rhoB itself. In this context we would like to emphasize that the inhibitory effect of RhoB on its own expression is already seen with wild-type RhoB. This is important to notice, because it reflects the physiological situation after UV-induced increase in the amount of RhoB. Thus, the responsiveness ofrhoB to wild-type RhoB also provides strong evidence that the observed autoregulation of rhoB is physiologically relevant. Since inhibition of rhoB expression was already ∼90% with wild-type RhoB, it was difficult to detect stronger effects even by use of activated RhoB. Thus it was not surprising that we observed V14RhoB to elicit a similar inhibition of rhoBexpression as wild-type RhoB did (data not shown). The same is true if expression vectors coding for either V14RhoA or wild-type RhoA were used (data not shown). The activity of RhoA and RhoB as inhibitors ofrhoB expression is also supported by the finding that blockage of Rho (RhoA, RhoB) activity by overexpression of the Rho inhibitory molecule Rho-GDI resulted in a strong increase in the activity of the rhoB promoter. Rho-GDI was also shown to be a negative regulator of Rac (41Fukumoto Y. Kaibuchi K. Hori Y. Jujioka H. Araki S. Ueda T. Kikuchi T. Takai Y. Oncogene. 1990; 9: 1321-1328Google Scholar). However, its inhibitory effect on Rho proteins (both RhoA and RhoB) obviously becomes predominant under conditions of overexpression, resulting in activation of therhoB promoter. The assumption of a preferential action of Rho-GDI on Rho, at least under conditions of Rho-GDI overexpression, is in agreement with the observation that microinjection of Rho-GDI causes cell rounding which is supposed to be mainly due to inactivation of RhoA (62Miura Y. Kikuchi A. Musha T. Kuroda S. Yaku H. Sasaki T. Takai Y. J. Biol. Chem. 1993; 268: 510-515Abstract Full Text PDF PubMed Google Scholar). Furthermore, overexpression of Rho-GDI exerted no effect on Rac-mediated activation of JNK (13Coso A.A. Chiariello M. Yu J.-C. Teramoto H. Crespo P. Xu N. Miki T. Gutkind J.S. Cell. 1995; 81: 1137-1146Abstract Full Text PDF PubMed Scopus (1559) Google Scholar). Rho proteins are known to participate in the regulation of the actin cytoskeleton (7Ridley A.J. Hall A. Cell. 1992; 70: 389-399Abstract Full Text PDF PubMed Scopus (3797) Google Scholar, 8Paterson H.F. Self A.J. Garrett M.D. Just I. Aktories K. Hall A. J. Cell Biol. 1990; 11: 1001-1007Crossref Scopus (567) Google Scholar, 10Hall A. Mol. Cell. Biol. 1992; 3: 475-479Crossref Scopus (173) Google Scholar) and cooperative action of Rho and Rac on actin cytoskeleton has been described (63Downward J. Nature. 1992; 359: 273-274Crossref PubMed Scopus (27) Google Scholar). On the other hand, opposite effects of Rac/Cdc42 and RhoA have been shown on neurite outgrowth (64Kozma R. Sarner S. Ahmed S. Lim L. Mol. Cell. Biol. 1997; 17: 1201-1211Crossref PubMed Scopus (535) Google Scholar). This finding indicates that RhoA and Rac inversively interfere with signal mechanisms involved in neurite development and collapse, respectively. Thus, it appears likely that Rac has stimulating effects whereas RhoA,B exerts inhibitory activity on the signaling which is involved in the regulation of rhoB expression upon UV irradiation.In summary, having cloned and analyzed the promoter of the mouserhoB gene, we present evidence that the rhoBpromoter is activated by UVC and other forms of genotoxic stress, and that UV activation of rhoB does not require JNK, ERK, and p38 MAP kinase. Therefore, the UV activation of the rhoBgene is different from other immediate-early genes such as c-jun and c-fos. Furthermore, rhoBactivity is stimulated by Rac but not by Cdc42 and is down-modulated by its own product RhoB and the related RhoA protein. This negative regulatory feedback might be functionally important in restoring the steady-state level of RhoB upon exposure of cells to UVC and other genotoxic agents.AcknowledgmentWe thank T. Hunter (San Diego, CA) for ratrhoB cDNA, K. Aktories (Freiburg, Germany) forrac1, rhoA V14rhoA, andrho-GDI cDNA, A. Hall (London, UK) for generously providing us with cdc42, N17cdc42, and V12cdc42 expression constructs as well as expression constructs encoding V12rac and V14rhoB, H. J. Rahmsdorf (Karlsruhe, Germany) for the Coll-CAT construct, and E. F. Wagner (Vienna, Austria) and A. Balmain (Glasgow, UK) for c-Fos and p53-deficient cell lines. Furthermore, we thank C. Kost for technical assistance. The Rho subfamily of small GTP-binding proteins play an important regulatory role in diverse cellular functions, including endocytosis (1Schmalzing G. Richter H.P. Hansen A. Schwarz W. Just I. Aktories K. J. Cell Biol. 1995; 130: 1319-1332Crossref PubMed Scopus (96) Google Scholar), membrane ruffling (2Ridley A.J. Paterson H.F. Johnston C.L. Diekmann D. Hall A. Cell. 1992; 70: 401-410Abstract Full Text PDF PubMed Scopus (3050) Google Scholar, 3Michiels F. Habets G.G. Stam J.C. van-der-Kammen R.A. Collard J.G. Nature. 1995; 375: 338-340Crossref PubMed Scopus (506) Google Scholar), cell cycle progress (4Olson M.F. Ashworth A. Hall A. Science. 1995; 269: 1270-1272Crossref PubMed Scopus (1055) Google Scholar), transformation (5Qiu R.-G. Chen J. Kirn D. McCormick F. Symons M. Nature. 1995; 374: 457-459Crossref PubMed Scopus (812) Google Scholar, 6Prendergast G.C. Khosravi-Far R. Solski P.A. Kurzawa H. Lebowitz P.F. Der C.J. Oncogene. 1995; 10: 2289-2296PubMed Google Scholar), and the organization of the cytoskeleton (7Ridley A.J. Hall A. Cell. 1992; 70: 389-399Abstract Full Text PDF PubMed Scopus (3797) Google Scholar, 8Paterson H.F. Self A.J. Garrett M.D. Just I. Aktories K. Hall A. J. Cell Biol. 1990; 11: 1001-1007Crossref Scopus (567) Google Scholar, 9Wiegers W. Just I. Müller H.M. Hellwig A. Traub P. Aktories K. Eur. J. Cell Biol. 1991; 54: 237-245PubMed Google Scholar, 10Hall A. Mol. Cell. Biol. 1992; 3: 475-479Crossref Scopus (173) Google Scholar). Recently the small GTPases Rac and Cdc42 have been shown to selectively activate c-Jun N-terminal kinase (JNK) signaling without affecting MAP kinase (MAPK), 1The abbreviations used are: MAPK, mitogen-activated protein kinase; IL-1, interleukin-1; TNF-α, tumor necrosis factor-α; PI 3-kinase, phosphatidylinositol 3-kinase; kb, kilobase(s); PCR, polymerase chain reaction; TPA, 12-O-tetradecanoylphorbol-13-acetate; CAT, chloramphenicol acetyltransferase; bp, base pair(s); INF-γ, interferon-γ; GDI, guanine-dissociation inhibitor; UVC, UV light (254 nm). 1The abbreviations used are: MAPK, mitogen-activated protein kinase; IL-1, interleukin-1; TNF-α, tumor necrosis factor-α; PI 3-kinase, phosphatidylinositol 3-kinase; kb, kilobase(s); PCR, polymerase chain reaction; TPA, 12-O-tetradecanoylphorbol-13-acetate; CAT, chloramphenicol acetyltransferase; bp, base pair(s); INF-γ, interferon-γ; GDI, guanine-dis" @default.
W2026748045 created "2016-06-24" @default.
W2026748045 creator A5018660823 @default.
W2026748045 creator A5026593378 @default.
W2026748045 date "1997-12-01" @default.
W2026748045 modified "2023-10-17" @default.
W2026748045 title "rhoB Encoding a UV-inducible Ras-related Small GTP-binding Protein Is Regulated by GTPases of the Rho Family and Independent of JNK, ERK, and p38 MAP Kinase" @default.
W2026748045 cites W1488959765 @default.
W2026748045 cites W1539871462 @default.
W2026748045 cites W1555489233 @default.
W2026748045 cites W1555692789 @default.
W2026748045 cites W1587892340 @default.
W2026748045 cites W1588986801 @default.
W2026748045 cites W1591414362 @default.
W2026748045 cites W1602846778 @default.
W2026748045 cites W1934347187 @default.
W2026748045 cites W1964100540 @default.
W2026748045 cites W1965372133 @default.
W2026748045 cites W1971827319 @default.
W2026748045 cites W1971915141 @default.
W2026748045 cites W1974653642 @default.
W2026748045 cites W1984903682 @default.
W2026748045 cites W1985462906 @default.
W2026748045 cites W1988756673 @default.
W2026748045 cites W1989143807 @default.
W2026748045 cites W1990989603 @default.
W2026748045 cites W2001399809 @default.
W2026748045 cites W2003962192 @default.
W2026748045 cites W2007660746 @default.
W2026748045 cites W2015519364 @default.
W2026748045 cites W2026326077 @default.
W2026748045 cites W2026951979 @default.
W2026748045 cites W2027810531 @default.
W2026748045 cites W2029872541 @default.
W2026748045 cites W2035936653 @default.
W2026748045 cites W2042584344 @default.
W2026748045 cites W2047743989 @default.
W2026748045 cites W2053257956 @default.
W2026748045 cites W2053362861 @default.
W2026748045 cites W2054760273 @default.
W2026748045 cites W2055181868 @default.
W2026748045 cites W2061587634 @default.
W2026748045 cites W2070061120 @default.
W2026748045 cites W2072371497 @default.
W2026748045 cites W2087172814 @default.
W2026748045 cites W2093226717 @default.
W2026748045 cites W2094872845 @default.
W2026748045 cites W2095416319 @default.
W2026748045 cites W2106911358 @default.
W2026748045 cites W2115120555 @default.
W2026748045 cites W2115541224 @default.
W2026748045 cites W2127150495 @default.
W2026748045 cites W2133837411 @default.
W2026748045 cites W2142638534 @default.
W2026748045 cites W2147242002 @default.
W2026748045 cites W2155868854 @default.
W2026748045 cites W2168091755 @default.
W2026748045 cites W2170467038 @default.
W2026748045 cites W4293247451 @default.
W2026748045 cites W4294216491 @default.
W2026748045 doi "https://doi.org/10.1074/jbc.272.49.30637" @default.
W2026748045 hasPubMedId "https://pubmed.ncbi.nlm.nih.gov/9388198" @default.
W2026748045 hasPublicationYear "1997" @default.
W2026748045 type Work @default.
W2026748045 sameAs 2026748045 @default.
W2026748045 citedByCount "79" @default.
W2026748045 countsByYear W20267480452012 @default.
W2026748045 countsByYear W20267480452013 @default.
W2026748045 countsByYear W20267480452015 @default.
W2026748045 countsByYear W20267480452016 @default.
W2026748045 countsByYear W20267480452017 @default.
W2026748045 countsByYear W20267480452018 @default.
W2026748045 countsByYear W20267480452022 @default.
W2026748045 crossrefType "journal-article" @default.
W2026748045 hasAuthorship W2026748045A5018660823 @default.
W2026748045 hasAuthorship W2026748045A5026593378 @default.
W2026748045 hasBestOaLocation W20267480451 @default.
W2026748045 hasConcept C104317684 @default.
W2026748045 hasConcept C1167327 @default.
W2026748045 hasConcept C118716 @default.
W2026748045 hasConcept C132149769 @default.
W2026748045 hasConcept C181199279 @default.
W2026748045 hasConcept C184235292 @default.
W2026748045 hasConcept C185592680 @default.
W2026748045 hasConcept C207332259 @default.
W2026748045 hasConcept C2777093181 @default.
W2026748045 hasConcept C2778917187 @default.
W2026748045 hasConcept C2781187634 @default.
W2026748045 hasConcept C501734568 @default.
W2026748045 hasConcept C51551487 @default.
W2026748045 hasConcept C55493867 @default.
W2026748045 hasConcept C57074206 @default.
W2026748045 hasConcept C62478195 @default.
W2026748045 hasConcept C80631254 @default.
W2026748045 hasConcept C85771745 @default.
W2026748045 hasConcept C86803240 @default.
W2026748045 hasConcept C95444343 @default.
W2026748045 hasConceptScore W2026748045C104317684 @default.