PIAS1 activates the expression of smooth muscle cell differentiation marker genes by interacting with serum response factor and class I basic helix-loop-helix proteins
PIAS1 activates the expression of smooth muscle cell differentiation marker genes by interacting with serum response factor and class I basic helix-loop-helix proteins
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DOI：
10.1128/mcb.25.18.8009-8023.2005
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发表时间：
2005-09-01
影响因子：
5.3
通讯作者：
Owens, GK
中科院分区：
文献类型：
--
作者：
Kawai-Kowase, K;Kumar, MS;Owens, GK
虽然血管疾病的一个重要组成部分是调节血管平滑肌细胞(SMC)的分化状态，但调控SMC分化的机制相对较少。我们以前已经证明，E-box和普遍表达的I类碱性螺旋-环-螺旋(BHLH)蛋白，包括E2-2和E12，在SMC分化标志基因SMα-肌动蛋白基因的调控中起着重要的作用。本研究的目的是鉴定SMC中与I类bHLH蛋白结合的蛋白，并调控SMC分化标志基因的转录调控。在此，我们报道了活化STAT蛋白抑制因子(PIAS)家族的成员与I类bHLH因子和血清反应因子(SRF)相互作用。通过酵母双杂交筛选、哺乳动物双杂交试验和/或免疫共沉淀试验，PIAS1与E2-2和E12相互作用。PIAS1过表达可显著激活SMC中SMα-肌动蛋白启动子和mRNA的表达，以及SM肌球蛋白重链和SM22α的表达，而PIAS1的小干扰RNA则降低这些启动子的活性以及内源性mRNA的表达，并使SRF与完整染色质内的SMα-肌动蛋白启动子结合。有意义的是，PIAS1与SRF结合，并激活了野生型但不是SRF-/-胚胎干细胞中SMα-肌动蛋白启动子的表达。这些结果为PIAS1通过与SRF和I类bHLH蛋白的协同作用调节SMC标记基因的转录激活提供了新的证据。
Although a critical component of vascular disease is modulation of the differentiated state of vascular smooth muscle cells (SMC), the mechanisms governing SMC differentiation are relatively poorly understood. We have previously shown that E-boxes and the ubiquitously expressed class I basic helix-loop-helix (bHLH) proteins, including E2-2 and E12, are important in regulation of the SMC differentiation marker gene, the SM alpha-actin gene. The aim of the present study was to identify proteins that bind to class I bHLH proteins in SMC and modulate transcriptional regulation of SMC differentiation marker genes. Herein we report that members of the protein inhibitor of activated STAT (PIAS) family interact with class I bHLH factors as well as serum response factor (SRF). PIAS1 interacted with E2-2 and E12 based on yeast two-hybrid screens, mammalian two-hybrid assays, and/or coimmunoprecipitation assays. Overexpression of PIAS1 significantly activated the SM a-actin promoter and mRNA expression, as well as SM myosin heavy chain and SM22 alpha, whereas a small interfering RNA for PIAS1 decreased activity of these promoters, as well as endogenous mRNA expression, and SRF binding to SM alpha-actin promoter within intact chromatin in cultured SMC. Of significance, PIAS1 bound to SRF and activated SM alpha-actin promoter expression in wild-type but not SRF-/- embryonic stem cells. These results provide novel evidence that PIAS1 modulates transcriptional activation of SMC marker genes through cooperative interactions with both SRF and class I bHLH proteins.