Spatial interplay between PIASy and FIP200 in the regulation of signal transduction and transcriptional activity
Spatial interplay between PIASy and FIP200 in the regulation of signal transduction and transcriptional activity
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DOI：
10.1128/mcb.01210-07
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发表时间：
2008-04-01
影响因子：
5.3
通讯作者：
Dejean, Anne
中科院分区：
文献类型：
--
作者：
Martin, Nadine;Schwamborn, Klaus;Dejean, Anne
活化STAT（皮亚斯）蛋白家族的蛋白抑制剂的成员通过作为E3 SUMO连接酶的作用或通过SUMO非依赖性效应参与基本细胞过程，包括转录调节。我们在这里报告的FIP 200（200 kDa的黏着斑激酶家族相互作用蛋白）作为一个新的PIASy相互作用蛋白的鉴定。我们表明，这种相互作用取决于PIASy的环指和FIP 200的羧基末端的完整性。体外和体内的糖基化测定均未能揭示FIP 200的任何糖基化，表明FIP 200不是真正的SUMO底物。免疫荧光显微镜和亚细胞分级分离，无论是在强制PIASy表达或在PIASy的情况下，揭示了与PIASy的相互作用重新分配FIP 200从细胞质到细胞核，与取消TSC/S6 K信号的FIP 200调节相关。相反，FIP 200通过PIASy增强p21启动子的转录激活，而PIASy转录活性在FIP 200通过RNA干扰耗尽后严重降低。染色质免疫沉淀分析表明内源性PIASy和FTP 200共募集到p21启动子。总之，这些结果提供了第一个证据的存在一个密切的空间控制模式的调节FTP 200和PIASy核质功能。
The members of the protein inhibitor of activated STAT (PIAS) family of proteins are implicated in fundamental cellular processes, including transcriptional regulation, either through action as E3 SUMO ligases or through SUMO-independent effects. We report here the identification of FIP200 (focal adhesion kinase family-interacting protein of 200 kDa) as a new PIASy-interacting protein. We show that the interaction depends on the integrity of the RING finger of PIASy and the carboxy terminus of FIP200. Both in vitro and in vivo surnoylation assays failed to reveal any surnoylation of FIP200, suggesting that FIP200 is not a bona fide SUMO substrate. Immunofluorescence microscopy and subcellular fractionation, either upon forced PIASy expression or in the absence of PIASy, revealed that interaction with PIASy redistributes FIP200 from the cytoplasm to the nucleus, correlating with abrogation of FIP200 regulation of TSC/S6K signaling. Conversely, FIP200 enhances the transcriptional activation of the p21, promoter by PIASy whereas PIASy transcription activity is severely reduced upon FIP200 depletion by RNA interference. Chromatin inummoprecipitation analysis demonstrates that endogenous PIASy and FTP200 are corecruited to the p21 promoter. Altogether, these results provide the first evidence for the existence of a close-spatially controlled-mode of regulation of FTP200 and PIASy nucleocytoplasmic functions.