Department of Pharmacology, University of Illinois at Chicago, 835 S. Wolcott Avenue Room E403 (m/c 868), Chicago, IL 60612, USA.
Cell Signal. 2013 Nov;25(11):2085-92. doi: 10.1016/j.cellsig.2013.06.012. Epub 2013 Jun 29.
p115RhoGEF is a member of a family of Rho-specific guanine nucleotide exchange factors that also contains a regulator of G protein signaling homology domain (RH-RhoGEFs) that serves as a link between Gα13 signaling and RhoA activation. While the mechanism of regulation of p115RhoGEF by Gα13 is becoming well-known, the role of other regulatory mechanisms, such as post-translational modification or autoinhibition, in mediating p115RhoGEF activity is less well-characterized. Here, putative phosphorylation sites on p115RhoGEF are identified and characterized. Mutation of Ser(330) leads to a decrease in serum response element-mediated transcription as well as decreased activation by Gα13 in vitro. Additionally, this study provides the first report of the binding kinetics between full-length p115RhoGEF and RhoA in its various nucleotide states and examines the binding kinetics of phospho-mutant p115RhoGEF to RhoA. These data, together with other recent reports on regulatory mechanisms of p115RhoGEF, suggest that this putative phosphorylation site serves as a means for initiation or relief of autoinhibition of p115RhoGEF, providing further insight into the regulation of its activity.
p115RhoGEF 是 Rho 特异性鸟嘌呤核苷酸交换因子家族的成员，其中还包含 G 蛋白信号同源结构域（RH-RhoGEFs）调节剂，它作为 Gα13 信号和 RhoA 激活之间的联系。虽然 p115RhoGEF 受 Gα13 调节的机制已广为人知，但其他调节机制（如翻译后修饰或自动抑制）在介导 p115RhoGEF 活性方面的作用还不太清楚。本文鉴定并表征了 p115RhoGEF 上的假定磷酸化位点。Ser(330)的突变导致血清反应元件介导的转录减少以及体外 Gα13 激活减少。此外，本研究首次报道了全长 p115RhoGEF 与各种核苷酸状态下的 RhoA 之间的结合动力学，并研究了磷酸化突变 p115RhoGEF 与 RhoA 的结合动力学。这些数据与其他最近关于 p115RhoGEF 调节机制的报告一起，表明该假定的磷酸化位点可作为 p115RhoGEF 自动抑制的起始或缓解的手段，进一步深入了解其活性的调节。
