Laboratory of Experimental Immunology, Institute of Medical Technology, Tampere University, Tampere, Finland.
FASEB J. 2010 Nov;24(11):4467-79. doi: 10.1096/fj.10-162784. Epub 2010 Jul 12.
JAK/STAT signaling pathway is evolutionarily conserved and tightly regulated. We carried out a reporter-based genome-wide RNAi in vitro screen to identify genes that regulate Drosophila JAK/STAT pathway and found 5 novel regulators. Of these, CG14225 is a negative regulator structurally related to the Drosophila JAK/STAT pathway receptor Domeless, especially in the extracellular domain, and to the mammalian IL-6 receptor and the signal transducer gp130. CG14225 coimmunoprecipitates with Domeless and its associated kinase hopscotch in S2 cells. CG14225 RNAi caused hyperphosphorylation of the transcription factor Stat92E in S2 cells on stimulation with the Drosophila JAK/STAT pathway ligand unpaired. CG14225 RNAi in vivo hyperactivated JAK/STAT target genes on septic injury and enhanced unpaired-induced eye overgrowth, and was thus named the eye transformer (ET). In the gastrointestinal infection model, where JAK/STAT signaling is important for stem cell renewal, CG14225/ET RNAi was protective in vivo. In conclusion, we have identified ET as a novel negative regulator of the Drosophila JAK/STAT pathway both in vitro and in vivo, and it functions in regulating Stat92E phosphorylation.
JAK/STAT 信号通路在进化上是保守的，并受到严格的调控。我们进行了基于报告基因的全基因组 RNAi 体外筛选，以鉴定调控果蝇 JAK/STAT 通路的基因，发现了 5 个新的调控因子。其中，CG14225 是一个结构上与果蝇 JAK/STAT 通路受体 Dome-less 相关的负调控因子，特别是在细胞外结构域，与哺乳动物的 IL-6 受体和信号转导蛋白 gp130 相关。CG14225 在 S2 细胞中与 Dome-less 及其相关激酶 hopscotch 共免疫沉淀。在受到果蝇 JAK/STAT 通路配体 unpaired 的刺激后，CG14225 RNAi 导致 S2 细胞中转录因子 Stat92E 的过度磷酸化。CG14225 在体内 RNAi 过度激活了 JAK/STAT 靶基因对败血症损伤的反应，并增强了 unpaired 诱导的眼睛过度生长，因此被命名为 eye transformer (ET)。在胃肠道感染模型中，JAK/STAT 信号通路对干细胞更新很重要，CG14225/ET RNAi 在体内具有保护作用。总之，我们已经在体外和体内鉴定出 ET 是果蝇 JAK/STAT 通路的一个新的负调控因子，它在调节 Stat92E 磷酸化方面发挥作用。
