Maynard Mindy A, Ohh Michael
Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, Toronto, Ont., Canada.
Am J Nephrol. 2004 Jan-Feb;24(1):1-13. doi: 10.1159/000075346. Epub 2003 Dec 3.
The development of hereditary von Hippel-Lindau (VHL) disease and the majority of sporadic kidney cancers are due to the functional inactivation of the VHL gene. The product of the VHL gene, pVHL, in association with elongins B and C, cullin 2, and Rbx1 form an E3 ubiquitin-ligase complex VEC that targets the alpha subunits of hypoxia-inducible factor (HIF) for ubiquitination. Ubiquitin-tagged HIF-alpha proteins are subsequently degraded by the common 26S proteasome. pVHL functions as the substrate-docking interface that specifically recognizes prolyl-hydroxylated HIF-alpha. This hydroxylation occurs only in the presence of oxygen or normoxia. Thus, under hypoxia, HIF-alpha subunits are no longer subjected to degradation and are thereby able to dimerize with the common and constitutively stable beta subunits. The heterodimeric HIFs upregulate a myriad of hypoxia-inducible genes, triggering our physiologic response to hypoxia. Inappropriate accumulations of HIF-alpha in VHL disease are believed to contribute to the pathogenesis via the upregulation of several of these HIF target genes. Our current molecular understanding of the roles of HIF and pVHL in the development of VHL-associated clear-cell renal cell carcinoma (CC-RCC) is the focus of this review.
遗传性冯·希佩尔-林道(VHL)病以及大多数散发性肾癌的发生是由于VHL基因的功能失活。VHL基因的产物pVHL与延伸蛋白B和C、cullin 2以及Rbx1结合形成E3泛素连接酶复合物VEC,该复合物将缺氧诱导因子(HIF)的α亚基作为泛素化的靶点。随后,带有泛素标签的HIF-α蛋白被常见的26S蛋白酶体降解。pVHL作为底物对接界面,特异性识别脯氨酰羟化的HIF-α。这种羟化仅在有氧或常氧条件下发生。因此,在缺氧状态下,HIF-α亚基不再被降解,从而能够与常见的、组成型稳定的β亚基二聚化。异二聚体HIF上调大量缺氧诱导基因,引发我们对缺氧的生理反应。在VHL病中,HIF-α的不适当积累被认为通过上调这些HIF靶基因中的几个而导致发病机制。本文综述聚焦于我们目前对HIF和pVHL在VHL相关透明细胞肾细胞癌(CC-RCC)发生中作用的分子理解。