Pellets of infected cells were resuspended in radioimmunoprecipitation assay (RIPA) buffer (1 mM Tris, pH 7.4, 1% Triton X-100, 0.25% sodium deoxycholate, 5 M sodium chloride, 0.5 mM EDTA, 0.1% sodium dodecyl sulfate [SDS]) and a protease inhibitor cocktail (Roche). Samples were mixed ...