CHX assay measuring pVHL stability, showing mutant VHL proteins decreased half-life in vitro. The 786-0 cells were stably transfected with plasmids expressing VHL^wt, VHL^P138L, and VHL^H191D mutants. Clones were treated with cycloheximide (CHX, 200 μM) for 0, 2, 4, 6, 8, and 10 hours, and lysates were subjected to western blot as indicated. Actin was used as the loading control. (Right) The relative quantitation of pVHL.