1. Supplemental Figure 1 HA-Ub + + + Hypoxia + - + MG132 + + + IP: IgG VHL kDa 118 - Ub-VHL 80 - 68 - 48 - 30 - 25 - IB: a-HA blot: HA 68 - 48 - 30 -  p25 VHL 25 -  p19 VHL 17 - blot: VHL 786-O G7F cells were transfected with an HA-Ubiquitin expression vector. Twenty four hours later, transfected cells were treated with MG-132 10 mM and with hypoxia or normoxia for 8 hours. Cells were lysed with NP40 buffer and immunoprecipitation was performed with anti-VHL (Ig32) antibody and western blot was further performed with anti-HA (Y11) (top panel) or anti-VHL (Ig32) (bottom panel), respectively.