Enhancement of mDia2 activity by Rho-kinase-dependent phosphorylation of the diaphanous autoregulatory domain.
Enhancement of mDia2 activity by Rho-kinase-dependent phosphorylation of the diaphanous autoregulatory domain.
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通过透明自动调节域的 Rho 激酶依赖性磷酸化增强 mDia2 活性。
DOI：
10.1042/bj20101700
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发表时间：
2011
期刊：
影响因子：
--
通讯作者：
Mack,ChristopherP
中科院分区：
文献类型：
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作者：
Staus,DeanP;Taylor,JoanM;Mack,ChristopherP
很明显，RhoA通过破坏DAD（透明自动调节结构域）和DID（透明抑制结构域）之间的分子相互作用来激活DRF（透明相关性蛋白）mDia 2。先前的研究表明，DAD内的碱性基序有助于mDia 2自身抑制，本研究中显示的结果表明这些残基结合DID内的保守酸性区域。此外，我们证明，mDia 2是磷酸化的ROCK（Rho激酶）在两个保守的残基（Thr 1061和Ser 1070）只是C-末端的DAD碱性区域。在全长分子的背景下，这些残基的拟磷酸化突变增强了mDia 2的活性，如通过增加肌动蛋白聚合、SRF（血清反应因子）依赖性平滑肌特异性基因转录和心肌蛋白相关转录因子B的核定位所测量的。生化和功能数据表明，T1061 E/S1070 E突变显着抑制DAD与DID相互作用的能力，并增强RhoA对mDia 2的激活。总之，本研究的结果表明，ROCK依赖性磷酸化的mDia 2 DAD是一个重要的决定因素mDia 2的活动，这种信号机制影响肌动蛋白聚合和平滑肌细胞特异性基因表达。
It is clear that RhoA activates the DRF (diaphanous-related formin) mDia2 by disrupting the molecular interaction between the DAD (diaphanous autoregulatory domain) and the DID (diaphanous inhibitory domain). Previous studies indicate that a basic motif within the DAD contributes to mDia2 auto-inhibition, and results shown in the present study suggest these residues bind a conserved acidic region within the DID. Furthermore, we demonstrate that mDia2 is phosphorylated by ROCK (Rho-kinase) at two conserved residues (Thr1061and Ser1070) just C-terminal to the DAD basic region. Phosphomimetic mutations to these residues in the context of the full-length molecule enhanced mDia2 activity as measured by increased actin polymerization, SRF (serum response factor)-dependent smooth muscle-specific gene transcription, and nuclear localization of myocardin-related transcription factor B. Biochemical and functional data indicate that the T1061E/S1070E mutation significantly inhibited the ability of DAD to interact with DID and enhanced mDia2 activation by RhoA. Taken together, the results of the present study indicate that ROCK-dependent phosphorylation of the mDia2 DAD is an important determinant of mDia2 activity and that this signalling mechanism affects actin polymerization and smooth muscle cell-specific gene expression.