Acetylation-Dependent IFN Signal Transduction

I型干扰素(V)影响几乎所有种类的细胞的分化、增殖和存活 具有多种细胞类型，对治疗慢性病等恶性肿瘤有效。 髓系白血病。近年来，干扰素在固体肿瘤化疗中的应用已经 受到了相当大的关注。干扰素激活的STAT2、STAT1和IRF9形成 转录因子干扰素刺激基因因子-3(ISGF3)复合体，与 干扰素刺激反应元件(ISRE)序列，用于转录激活。 干扰素激活的STAT蛋白也形成同源或异源二聚体，与SIS诱导性结合 调节基因表达的元件(SIE)。干扰素受体由两个同源基因组成 亚基：干扰素r1和干扰素r2。干扰素与干扰素R2结合以激发其关联性 使用干扰素？R1。干扰素？R1和干扰素？R2被它们的相关基因交叉磷酸化 酪氨酸激酶(JAK1和TYK2)，紧随其后的是STAT2和STAT1 募集和磷酸化激活。干扰素的激活机制 IRF9未知。治疗可增强IRF9依赖的转录激活 含有脱乙酰酶抑制剂的细胞，表明IRF9的激活涉及乙酰化。我们 募集肿瘤抑制物样转录辅因子检测干扰素受体2乙酰化 CREB结合蛋白(CBP)或其同源基因p300。然后，乙酰化干扰素？R2可以 招募IRF9。IRF9以及STAT2和STAT1都是在CBP乙酰化之前 形成转录活性的ISGF3复合体。干扰素？R也招募脱乙酰酶 包括SIRT和HDAC成员。尽管酪氨酸磷酸化长期以来一直是 我们的发现被认为在细胞因子受体信号转导中起着至关重要的作用 基于初步数据和蛋白质二级结构分析，挑战这一点 概念。这里要检验的首要假设是CBP/p300介导的 干扰素引发的乙酰化级联反应在信号转导中起着不可或缺的作用 用于抗增殖、细胞凋亡和抗转移基因的调节。干扰干扰素？R 脱乙酰酶与脱乙酰酶抑制剂联合使用可改善疗效。 干扰素在癌症中的作用。我们将应用定点突变，FRET技术，作为 以及我们实验室开发的抗体阵列技术，以(1)定义 CBP/p300与细胞内干扰素受体激活相关的乙酰转移酶活性 (2)用HDAC或SIRT分析干扰素受体、STAT1和ISGF3脱乙酰基。 信号终止；以及(3)确定乙酰化的STAT1二聚体或ISGF3 复合体在干扰素介导的抗增殖、促凋亡和抗肿瘤转移中起关键作用 癌细胞中的基因调控。这些方法将有助于阐明 乙酰化和去乙酰化在调节干扰素受体激活、STAT二聚体和 ISGF3复合体的形成，用于信号转导和转录，并允许我们 最大限度地发挥干扰素在癌症治疗中的应用。

Type I interferon (v affect cell differentiation, proliferation, and survival in nearly all kinds of cell types, and are efficacious in the treatment of malignancies such as chronic myeloid leukemia. In recent years, the usage of IFN¿ for solid cancer chemotherapy has received considerable attention. IFN¿-activated STAT2, STAT1, and IRF9 form the transcription factor IFN-stimulated gene factor-3 (ISGF3) complex, which binds to interferon stimulated response element (ISRE) sequence for transcriptional activation. IFN¿ activated STAT proteins also form homo- or hetero-dimer that bind to sis-inducible element (SIE) to regulate gene expression. IFN¿ receptor (IFN¿R) consist two cognate subunits: IFN¿R1 and IFN¿R2. IFN¿ binds IFN¿R2 to instigate its association with IFN¿R1. IFN¿R1 and IFN¿R2 are cross-phosphorylated by their associated tyrosine kinases (Jak1 and Tyk2), followed by subsequent STAT2 and STAT1 recruitment and phosphorylational activation. The mechanism of how IFN¿ activates IRF9 is unknown. IRF9-dependent transcriptional activation can be enhanced by treating the cells with deacetylase inhibitors, suggesting IRF9 activation involves acetylation. We detected IFN¿R2 acetylation by recruiting tumor suppressor-like transcription cofactor CREB-binding protein (CBP) or its homologous p300. Acetylated IFN¿R2 can then recruit IRF9. IRF9 as well as STAT2 and STAT1 are all acetylated by CBP prior to forming the transcriptional active ISGF3 complex. IFN¿R also recruits deacetylases including SIRT and HDAC members. Although tyrosine phosphorylation has long been accepted to play a paramount role in cytokine receptor signal transduction, our findings based upon preliminary data and protein secondary structural analysis challenge this concept. The overarching hypothesis to be tested here is that CBP/p300-mediated acetylation cascade triggered by IFN¿ plays an indispensable role in signal transduction for anti-proliferation, proapotosis, and anti-metastasis gene regulation. Disrupting IFN¿R and deacetylase association with deacetylase inhibitors may improve the therapeutic effects of IFN¿ in cancer. We will apply site-directed mutagenesis, FRET technology, as well as the antibody array technology developed in our lab in order to (1) define the acetyltransferase activity associated with CBP/p300 on IFN¿R activation in intracellular signaling; (2) analyze IFN¿R, STAT1 and ISGF3 deacetylation by HDAC or SIRT in signal termination; and (3) determine whether acetylated STAT1 dimer or ISGF3 complex is critical for IFN¿- mediated anti-proliferation, proapoptosis, and antimetastasis gene regulation in cancer cells. These approaches will help elucidate the function of acetylation and deacetylation in the regulation of IFN¿R activation, STAT dimer, and ISGF3 complex formation for signal transduction and transcription, and allow us to maximize the therapeutic applications of IFN¿ for cancer.