Role of prolyl hydroxylation in oncogenically stabilized hypoxia-inducible factor-1α
Role of prolyl hydroxylation in oncogenically stabilized hypoxia-inducible factor-1α
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DOI：
10.1074/jbc.m206922200
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发表时间：
2002-10-18
影响因子：
4.8
通讯作者：
Giaccia, AJ
中科院分区：
文献类型：
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作者：
Chan, DA;Sutphin, PD;Giaccia, AJ
低氧诱导因子-1（HIF-1）蛋白的稳定性对于其在低氧条件下作为基因表达调节剂的作用至关重要。在这里，采用一种新的羟化特异性抗体，我们直接表明，脯氨酸564的HIF-1 α和脯氨酸531的HIF-2 α在常氧下被羟化。重要的是，HIF-1 α Pro-564和HIF-2 α Pro-531的羟基化随着缺氧、氯化钴、去铁胺或二甲氧甘氨酸的处理而减少，而不管von Hippel-Lindau（VHL）肿瘤抑制基因的E3泛素连接酶活性如何。此外，在VHL缺陷细胞中，HIF-1 α Pro-564和HIF-2 α Pro-531在转变为缺氧后具有可检测量的羟基化，表明翻译后修饰是不可逆的。v-Src或RasV 12癌基因的引入导致含氧量正常的HIF-1 α的稳定和羟基化的Pro-564的丢失，表明癌基因诱导的HIF-1 α的稳定是通过抑制脯氨酰羟基化来发出信号的。相反，一个组成性激活的Akt癌基因在常氧下独立于脯氨酰羟基化而稳定HIF-1 α，提示HIF-1 α稳定的另一种机制。因此，这些结果表明，不同的癌基因的HIF-1 α稳定不同的途径。更重要的是，这些发现通过脯氨酰羟基化将肿瘤发生与含氧量正常的HIF-1 α表达联系起来。
Stabilization of the hypoxia-inducible factor-1 (HIF-1) protein is essential for its role as a regulator of gene expression under low oxygen conditions. Here, employing a novel hydroxylation-specific antibody, we directly show that proline 564 of HIF-1alpha and proline 531 of HIF-2alpha are hydroxylated under normoxia. Importantly, HIF-1alpha Pro-564 and HIF-2alpha Pro-531 hydroxylation is diminished with the treatment of hypoxia, cobalt chloride, desferrioxamine, or dimethyloxalyglycine, regardless of the E3 ubiquitin ligase activity of the von Hippel-Lindau (VHL) tumor suppressor gene. Furthermore, in VHL-deficient cells, HIF-1alpha Pro-564 and HIF-2alpha Pro-531 had detectable amounts of hydroxylation following transition to hypoxia, indicating that the post-translational modification is not reversible. The introduction of v-Src or RasV12 oncogenes resulted in the stabilization of normoxic HIF-1alpha and the loss of hydroxylated Pro-564, demonstrating that oncogene-induced stabilization of HIF-1alpha is signaled through the inhibition of prolyl bydroxylation. Conversely, a constitutively active Akt oncogene stabilized HIF-1alpha under normoxia independently of prolyl hydroxylation, suggesting an alternative mechanism for HIF-1alpha stabilization. Thus, these results indicate distinct pathways for HIF-1alpha stabilization by different oncogenes. More importantly, these findings link oncogenesis with normoxic HIF-1alpha expression through prolyl hydroxylation.