TY - JOUR
T1 - Ras controls tumor necrosis factor receptor-associated factor (TRAF)6-dependent induction of nuclear factor-kappa B - Selective regulation through receptor signaling components
AU - Caunt, Christopher J
AU - Kiss-Toth, E
AU - Carlotti, F
AU - Chapman, R
AU - Qwarnstrom, E E
PY - 2001
Y1 - 2001
N2 - In the present study, we show that Ras activity differentially controls interleukin (IL)-1 induced transcription factor activation by selective regulation of responses mediated by receptor complex components. Initial experiments revealed that stimulation with IL-1 caused a rapid, matrix-dependent activation of Ras. The effect was transient, peaking at 5 min and returning to base levels after 30 min. Activation correlated with pronounced changes in cell shape in EGFPH-Ras transfected cells. Transfection with the dominant negative mutant, Ras(Asn-17), inhibited IL-1 induced activation of the IL-8 promoter as well as of NF-kappaB and AP-1 synthetic promoters in transient transfection assays. Furthermore, overexpression of the IL-1 signaling proteins TRAF6 or MyD88 gave characteristic activation of IL-8, which was accentuated in the presence of IL-1. Co-transfection with Ras(Asn-17) gave a dose-dependent inhibition of TRAF6-induced responses in the presence and absence of IL-1, but had no effect on MyD88 mediated activity. Similarly, induction of NF-kappaB was abolished by Ras(Asn-17) only in TRAF6-transfected cells. In contrast, inhibiting Ras activity limited AP-1-mediated responses through both receptor complex proteins. Constitutively active Ras(VaI-12) increased the TRAF6 induced activity of the NF-kappaB pathway similar to the effect induced by IL-1, while the Ras(VaI-12) induced activity was not inhibited by co-transfection with a dominant negative TRAF6. Our data show that activation of the Ras GTPase is an early, matrix-dependent response in IL-1 signaling which participates in structural regulation of IL-1-induced genes. In addition, they show that the Ras induced effect selectively regulates TRAF6-mediated activation of the NF-kappaB pathway, suggesting that Ras GTPase represents a convergence point in structural and cytokine responses, with distinct effects on a subset of downstream signaling events.
AB - In the present study, we show that Ras activity differentially controls interleukin (IL)-1 induced transcription factor activation by selective regulation of responses mediated by receptor complex components. Initial experiments revealed that stimulation with IL-1 caused a rapid, matrix-dependent activation of Ras. The effect was transient, peaking at 5 min and returning to base levels after 30 min. Activation correlated with pronounced changes in cell shape in EGFPH-Ras transfected cells. Transfection with the dominant negative mutant, Ras(Asn-17), inhibited IL-1 induced activation of the IL-8 promoter as well as of NF-kappaB and AP-1 synthetic promoters in transient transfection assays. Furthermore, overexpression of the IL-1 signaling proteins TRAF6 or MyD88 gave characteristic activation of IL-8, which was accentuated in the presence of IL-1. Co-transfection with Ras(Asn-17) gave a dose-dependent inhibition of TRAF6-induced responses in the presence and absence of IL-1, but had no effect on MyD88 mediated activity. Similarly, induction of NF-kappaB was abolished by Ras(Asn-17) only in TRAF6-transfected cells. In contrast, inhibiting Ras activity limited AP-1-mediated responses through both receptor complex proteins. Constitutively active Ras(VaI-12) increased the TRAF6 induced activity of the NF-kappaB pathway similar to the effect induced by IL-1, while the Ras(VaI-12) induced activity was not inhibited by co-transfection with a dominant negative TRAF6. Our data show that activation of the Ras GTPase is an early, matrix-dependent response in IL-1 signaling which participates in structural regulation of IL-1-induced genes. In addition, they show that the Ras induced effect selectively regulates TRAF6-mediated activation of the NF-kappaB pathway, suggesting that Ras GTPase represents a convergence point in structural and cytokine responses, with distinct effects on a subset of downstream signaling events.
UR - http://dx.doi.org/10.1074/jbc.M006772200
U2 - 10.1074/jbc.M006772200
DO - 10.1074/jbc.M006772200
M3 - Article
SN - 0021-9258
VL - 276
SP - 6280
EP - 6288
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 9
ER -