Extended Data Fig. 3: Western blots showing ubiquitination of PTD-tagged viral M1 proteins.

HEK293T cells were co-transfected with constructs expressing HA- or Flag-tagged ubiquitin, Flag- or HA-tagged E3 ubiquitin ligases, and PTD-tagged viral M1 proteins or mutated PTD-tagged viral M1 proteins. The cells were treated with 10 μM MG-132 for 6 hours prior to being harvested at 36 h post-transfection. M1 proteins were immunoprecipitated for detection of the levels of ubiquitination (n = 3).