Activation of hypoxia-inducible transcription factor depends primarily upon redox-sensitive stabilization of its alpha subunit
Activation of hypoxia-inducible transcription factor depends primarily upon redox-sensitive stabilization of its alpha subunit
复制标题
DOI：
10.1074/jbc.271.50.32253
复制
发表时间：
1996-12-13
影响因子：
4.8
通讯作者：
Bunn, HF
中科院分区：
文献类型：
--
作者：
Huang, LE;Arany, Z;Bunn, HF
缺氧诱导因子 1 (HIF-1) 是一种异二聚体转录因子，对于许多生理学重要基因的缺氧诱导至关重要。我们提供的证据表明，HIF-1 活性的调节主要由 HLF-1 α 蛋白的稳定性决定。HIF-1 α 和 HIF-1 β mRNA 均在 HeLa 和 Hep3B 细胞中组成型表达，缺氧没有显着诱导， 然而，即使 HLF-1 α 过表达，HIF-1 α 蛋白在常氧细胞中也几乎检测不到，但在缺氧细胞中高度诱导，而 HIF-1 β 蛋白水平保持恒定，无论 pO(2) 如何。缺氧诱导的 HIF-1 结合以及 HIF-1 α 蛋白在体内急剧增加到正常氧张力后迅速大幅减少。此外，细胞短暂预暴露于过氧化氢可通过阻断 HIF-1 α 蛋白的积累选择性地阻止缺氧诱导的 HIF-1 结合，而用 H2O2 处理缺氧细胞提取物对 HIF-1 没有影响 绑定。这些观察结果表明，RIF-1a 蛋白的不稳定需要完整的氧化还原依赖性信号通路，在缺氧细胞提取物中，HIF-1 DNA 结合被巯基氧化可逆地消除，此外，向细胞提取物中添加还原硫氧还蛋白增强了 HIF-1 DNA 结合，与这些结果一致，硫氧还蛋白和 Ref-1 的过度表达显着 这些实验表明，HIF-1 的激活涉及 HIF-1 α 蛋白的氧化还原依赖性稳定化。
Hypoxia-inducible factor 1 (HIF-1) is a heterodimeric transcription factor that is critical for hypoxic induction of a number of physiologically important genes, We present evidence that regulation of HIF-1 activity is primarily determined by the stability of the HLF-1 alpha protein, Both HIF-1 alpha and HIF-1 beta mRNAs were constitutively expressed in HeLa and Hep3B cells with no significant induction by hypoxia, However, the HIF-1 alpha protein was barely detectable in normoxic cells, even when HLF-1 alpha was overexpressed, but was highly induced in hypoxic cells, whereas HIF-1 beta protein levels remained constant, regardless of pO(2). Hypoxia-induced HIF-1 binding as well as the HIF-1 alpha protein were rapidly and drastically decreased in vivo following an abrupt increase to normal oxygen tension, Moreover, short pre-exposure of cells to hydrogen peroxide selectively prevented hypoxia-induced HIF-1 binding via blocking accumulation of HIF-1 alpha protein, whereas treatment of hypoxic cell extracts with H2O2 had no effect on HIF-1 binding. These observations suggest that an intact redox-dependent signaling pathway is required for destabilization of the RIF-la protein, In hypoxic cell extracts, HIF-1 DNA binding was reversibly abolished by sulfhydryl oxidation, Furthermore, the addition of reduced thioredoxin to cell extracts enhanced HIF-1 DNA binding, Consistent with these results, overexpression of thioredoxin and Ref-1 significantly potentiated hypoxia-induced expression of a reporter construct containing the wild-type HIF-1 binding site, These experiments indicate that activation of HIF-1 involves redox-dependent stabilization of HIF-1 alpha protein.