Specif ically, type 1 IFNs can induce pro inflammatory gene transcription leadi

Silen cing TBRII not only reduced ATF2 activation but also that of Smad2, indicating the critical import ance of TBRII in mediating TGFB signaling. To further assess the role ABT-737 ic50 of TBRII, we transfected VSMCs with a dominant negative type II receptor HA TBRII, which has an HA tag at the N terminus but lacks expected but not the activation of ATF2. In addition, TBRII attenuated TGFB induced CRP2 expression 24 h later. Src family kinase mediates TBRII dependent TGFB activation of RhoA ROCK and ATF2 in VSMCs We next investigated how TBRII mediates ATF2 activation independent of TBRI in VSMCs. In JEG3 choriocarcinoma cells, Src kinase is involved in TGFB induced early signaling. In addition, c Src has been reported to mediate TGFB induced SMC gene expression.<br><br> We therefore examined whether in VSMCs Src activation was required to transmit TGFB signaling for ATF2 activation. The selective Src fam ily kinase inhibitor SU6656 dose dependently abrogated TGFB induced ATF2 AEB071 溶解度 activation. In contrast, SU6656 did not alter Smad2 phosphorylation by TGFB even at high doses. These data indicate that Src family kinase functions downstream of TBRII in transdu cing Smad independent TGFB signaling to activate ATF2. Since rapid Src activation by TGFB has been found to ef fectively activate Small GTPase RhoA in other cell systems, we then examined whether in VSMCs RhoA was activated downstream of Src family kinase. Indeed, TGFB enhanced RhoA activation and SU6656 inhibited TGFB induced RhoA activation. Furthermore, trans fection of VSMCs with control or RhoA siRNA revealed that RhoA knockdown attenuated TGFB induced ATF2 ac tivation but not that of Smad2.<br><br> In addition, siRNA mediated silencing of RhoA not only decreased acti vation of the signaling molecules at the early time point but also reduced TGFB induced CRP2 protein expression after AG-014699 分子量 24 h. These results suggest C terminal kinase domain and is thus incapable of phos phorylating and activating the type I receptor. Interest ingly, TBRII attenuated Smad2 phosphorylation as that Src family kinase RhoA signaling mediates TBRII dependent ATF2 activation and CRP2 expression by TGFB. Since RhoA kinase is a major target of RhoA and that ROCK has been implicated in SMC differenti ation by modulating TGFB Smad signaling, we ex amined whether ROCK functioned downstream of RhoA to regulate ATF2 activation.<br><br> Interestingly, treatment of VSMCs with ROCK inhibitor Y 27632 abolished ATF2 phosphorylation but not that of Smad2. Sup porting this notion, Y 27632 abrogated TGFB induced CRP2 protein expression after 24 h. JNK activation is required for TGFB induced phosphorylation of ATF2 Because MAP kinase pathways have been shown to contribute to TGFB signaling, we evaluated ac tivation of MAP kinase pathway in ATF2 phosphoryl ation. TGFB increased phosphorylation of JNK, p38, and ERK1 2. However, kinase inhibitor studies revealed that JNK inhibitor SP600125 but not p38 MAP kinase inhibitor SB203580 or ERK inhibitor U0126 abolished ATF2 phosphorylation. Interestingly, SP600125 did not affect TGFB induced Smad2 phosphorylation. To determine whether JNK inhibition ultimately affected CRP2 induction by TGFB, we first pretreated VSMCs with vehicle or SP600125 for 30 min, stimulated with or without TGFB for 24 h, then examined CRP2 expression levels.