INHIBITION OF CYTOKINE SIGNALING BY PIS PROTEINS

这项提案的长期目标是理解对 通过细胞因子进行基因表达。申请人最近克隆了cdna。 对于一个新的蛋白质家族的两个成员，术语最初是PIS (与STAT相互作用的蛋白质)，现在改为PIAS(蛋白质 与激活的STAT交互)。初步数据提交给 提示单个PIAS蛋白表现出特定的特异性 PIAS1和PIAS3中统计信息与STAT1和STAT3交互 分别进行了分析。此外，PIAS蛋白似乎能抑制STAT-DNA 相互作用和STAT诱导的基因表达。申请人提出建议 进一步鉴定PIAS蛋白。三个具体目标是 建议。首先，PIAS-STAT相互作用的分子基础将 以检查PIAS蛋白的哪些片段是必需的 并且足以与统计数据交互。第二，机制 PIAS蛋白抑制STAT功能的机制将被解决。这个 申请者将使用交叉连接来确定PIAS蛋白是否阻止 STATS和WILL在细胞中表达PIAS蛋白的二聚化检测 对统计数据核移位的影响。一项关于 细胞因子对PIAS功能的影响及寻找新的PIAS 还提出了蛋白质的概念。最后，PIAS3对IL6的影响 M1细胞和PIAS1对U3A-STAT1细胞中IFNG功能的影响 建议，这将涉及建立稳定的细胞系 过表达PIAS蛋白或可替代地应用 反义策略。

The long term goal of this proposal is to understand the regulation of gene expression by cytokines. The applicant has recently cloned cDNA for two members of a novel family of proteins, term originally PIS (Protein Interacting with STAT) and now changed to PIAS (Protein Interacting with Activated STAT). Preliminary data are presented to suggest that individual PIAS proteins display specificity for particular STATs in that PIAS1 and PIAS3 interact with STAT1 and STAT3 respectively. In addition, PIAS proteins appear to inhibit STAT-DNA interactions and STAT-induced gene expression. The applicant proposes to characterize further the PIAS proteins. Three specific aims are proposed. Firstly the molecular basis of the PIAS-STAT interaction will be defined, to examine which segments of the PIAS proteins are necessary and sufficient for the interaction with STATs. Secondly, the mechanisms by which PIAS proteins inhibit STAT function will be addressed. The applicant will use cross linking to determine if PIAS proteins block dimerization of STATs and will express PIAS proteins in cells to examine effects on the nuclear translocation of STATs. An examination of the effects of cytokines on PIAS function and a search for additional PIAS proteins is also proposed. Finally, the effects of PIAS3 on IL6 function in M1 cells and PIAS1 on IFNg function in U3A-STAT1 cells is proposed, which will involve creation of stable cell lines overexpressing the PIAS proteins or alternatively the application of anti-sense strategies.