Figure 4

Potential oxygen-sensing mechanisms and the role of the transcription factor HIF. This schematic shows the role of von Hippel-Lindau tumor-suppressor protein (shown as VHL) in mediating the regulation of HIF. It has emerged as a key factor in cellular responses to oxygen availability, being required for the oxygen-dependent proteolysis of the α subunits of HIF. The gray box indicates the reaction mechanisms involving the putative oxygen sensor. FADH, flavin adenine dinucleotide (reduced form); FAD, flavin adenine dinucleotide (oxidized form); 6PG, 6-phosphoglycerate; G6P, glucose-6-phosphate.