von Hippel-Lindau (VHL)

Von Hippel-Lindau (VHL) protein functions as a tumor suppressor and substrate recognition subunit of the Cullin2-RING E3 ligase complex (CRL2^VHL), mediating oxygen-sensing by targeting hypoxia-inducible factor alpha (HIF-α) for ubiquitination and proteasomal degradation^[1][2]. Loss or mutation of VHL disrupts HIF-α regulation, resulting in differential activation of HIF isoforms, where HIF-1α can suppress and HIF-2α can promote tumorigenesis^[3][4][5]. Mechanistically, VHL-mediated ubiquitination specifically regulates HIF-2α-driven transcriptional programs that control cell proliferation, angiogenesis, and erythropoiesis, as demonstrated in VHL-R200W polycythemia models and renal cell carcinoma (RCC) studies^[6][7][8]. Compared with related isoforms, HIF-2α exhibits tissue-specific oncogenic activity, particularly in proximal tubular epithelial cells, whereas HIF-1α exhibits tumor-suppressive effects^[4][9][10]. Experimental models, including zebrafish and conditional mouse knockouts, recapitulate VHL loss phenotypes such as hemangioblastomas, impaired visual function, and splenic erythropoiesis, facilitating pharmacological intervention studies^[11][12][13]. VHL-targeted small molecules, such as VH298 and belzutifan, stabilize VHL protein or inhibit HIF-2α activity, thereby modulating downstream hypoxia responses and providing a framework for therapeutic strategies in VHL-associated RCC and other neoplasms^[1][14]. Overall, precise regulation of VHL and HIF isoforms underpins disease pathogenesis, isoform-specific biology, and translational applications in inhibitor or agonist development^[2][4][9].