4.1R competitively interrupts the association of VHL and myogenin. C2C12 cells grown in 10-cm dishes were co-transfected with various combinations of HA-VHL, T7-myogenin, FLAG-4.1R, and empty vector pcDNA3, with a total of 24 μg of DNA, as indicated. Cells were lysed in IP buffer 48 h post-transfection and immunoprecipitated (IP) with an anti-HA antibody. lysate, equal amounts of lysates were analyzed via Western blotting (IB) for the exogenously expressed HA-VHL, T7-Myog, and FLAG-4.1R. IP:HA, anti-HA immunoprecipitates were equally divided and analyzed for HA-VHL and its associated T7-Myog and FLAG-4.1R with their respective antibodies.