Pro-apoptotic activity of inhibitory PAS domain protein (IPAS), a negative regulator of HIF-1, through binding to pro-survival Bcl-2 family proteins
Pro-apoptotic activity of inhibitory PAS domain protein (IPAS), a negative regulator of HIF-1, through binding to pro-survival Bcl-2 family proteins
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DOI：
10.1038/cdd.2011.47
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发表时间：
2011-11-01
影响因子：
12.4
通讯作者：
Sogawa, K.
中科院分区：
文献类型：
--
作者：
Torii, S.;Goto, Y.;Sogawa, K.
抑制性PAS（Per/Arnt/Sim）结构域蛋白（IPAS）是一种抑制缺氧诱导因子1（HIF-1）活性的显性负性转录因子。在这项研究中，我们表明，IPAS也作为一个促凋亡蛋白通过结合到促生存Bcl-2家族成员。在以前的论文中，我们报道了氯化钴诱导的NF-κ B依赖性IPAS抑制了PC 12细胞的缺氧反应。我们发现，在相同的条件下，延长孵育导致PC 12细胞凋亡。抑制IPAS诱导保护细胞免于凋亡。此外，IPAS的敲除恢复了细胞活力。EGFP-IPAS蛋白定位于细胞核和细胞质中，其中大部分与线粒体相关。线粒体IPAS诱导线粒体去极化和caspase-3激活。免疫沉淀分析显示IPAS与Bcl-x（L）、Bcl-w和Mcl-1相关。通过基于FLIM的FRET分析，在活细胞中也观察到IPAS与Bcl-x（L）的缔合，表明两种蛋白质之间的直接结合。IPAS通过抑制Bax与Bcl-x（L）的相互作用而导致Bcl-x（L）功能障碍。这些结果表明，IPAS作为一个双重功能的蛋白参与转录抑制和凋亡。Cell Death and Differentiation（2011）18，1711-1725; doi：10.1038/cdd.2011.47; 2011年5月6日在线发表
Inhibitory PAS (Per/Arnt/Sim) domain protein (IPAS) is a dominant negative transcription factor that represses hypoxia-inducible factor 1 (HIF-1) activity. In this study, we show that IPAS also functions as a pro-apoptotic protein through binding to pro-survival Bcl-2 family members. In a previous paper, we reported that NF-kappa B-dependent IPAS induction by cobalt chloride repressed the hypoxic response in PC12 cells. We found that prolonged incubation under the same conditions caused apoptosis in PC12 cells. Repression of IPAS induction protected cells from apoptosis. Furthermore, knockdown of IPAS recovered cell viability. EGFP-IPAS protein was localized in both the nucleus and the cytoplasm, with a large fraction associated with mitochondria. Mitochondrial IPAS induced mitochondria depolarization and caspase-3 activation. Immunoprecipitation assays revealed that IPAS is associated with Bcl-x(L), Bcl-w and Mcl-1. The association of IPAS with Bcl-x(L) was also observed in living cells by the FLIM-based FRET analysis, indicating direct binding between the two proteins. IPAS contributed to dysfunction of Bcl-x(L) by inhibiting the interaction of Bcl-x(L) with Bax. These results demonstrate that IPAS functions as a dual function protein involved in transcription repression and apoptosis. Cell Death and Differentiation (2011) 18, 1711-1725; doi: 10.1038/cdd.2011.47; published online 6 May 2011