Oregon Health & Science University Knight Cancer Institute, Oregon Health & Science University, Portland, Oregon 97239.
Oregon Health & Science University Knight Cancer Institute, Oregon Health & Science University, Portland, Oregon 97239.
J Biol Chem. 2012 Oct 12;287(42):35496-35505. doi: 10.1074/jbc.M112.400697. Epub 2012 Aug 20.
Lysine acetylation regulates protein stability and function. p300 is a component of the HIF-1 transcriptional complex and positively regulates the transactivation of HIF-1. Here, we show a novel molecular mechanism by which p300 facilitates HIF-1 activity. p300 increases HIF-1α (HIF1α) protein acetylation and stability. The regulation can be opposed by HDAC1, but not by HDAC3, and is abrogated by disrupting HIF1α-p300 interaction. Mechanistically, p300 specifically acetylates HIF1α at Lys-709, which increases the protein stability and decreases polyubiquitination in both normoxia and hypoxia. Compared with the wild-type protein, a HIF1α K709A mutant protein is more stable, less polyubiquitinated, and less dependent on p300. Overexpression of the HIF1α wild-type or K709A mutant in cancer cells lacking the endogenous HIF1α shows that the K709A mutant is transcriptionally more active toward the HIF-1 reporter and some endogenous target genes. Cancer cells containing the K709A mutant are less sensitive to hypoxia-induced growth arrest than the cells containing the HIF1α wild-type. Taken together, these data demonstrate a novel biological consequence upon HIF1α-p300 interaction, in which HIF1α can be stabilized by p300 via Lys-709 acetylation.
赖氨酸乙酰化调节蛋白质稳定性和功能。p300 是 HIF-1 转录复合物的组成部分，正向调节 HIF-1 的转录激活。在这里，我们展示了 p300 促进 HIF-1 活性的一种新的分子机制。p300 增加 HIF-1α（HIF1α）蛋白乙酰化和稳定性。该调节可以被 HDAC1 拮抗，但不能被 HDAC3 拮抗，并且通过破坏 HIF1α-p300 相互作用而被废除。从机制上讲，p300 特异性地在赖氨酸 709 处乙酰化 HIF1α，这增加了蛋白质的稳定性，并减少了在常氧和缺氧条件下的多泛素化。与野生型蛋白相比，HIF1α K709A 突变蛋白更稳定，多泛素化程度更低，对 p300 的依赖性更低。在缺乏内源性 HIF1α 的癌细胞中过表达 HIF1α 野生型或 K709A 突变体表明，K709A 突变体对 HIF-1 报告基因和一些内源性靶基因的转录活性更高。与含有 HIF1α 野生型的细胞相比，含有 K709A 突变体的癌细胞对低氧诱导的生长抑制的敏感性较低。总之，这些数据表明 HIF1α-p300 相互作用产生了一种新的生物学后果，其中 HIF1α 可以通过赖氨酸 709 乙酰化被 p300 稳定。
