Fig. 7

The tripartite interaction between I55 and F68 of CBFβ and W5 of Vif is sufficient to stabilize Vif–CBFβ interaction. a After treatment of 293T cells with CBFβ-specific siRNA, the cells were co-transfected with WT Flag-CBFβ or substitution mutants of Flag-CBFβ and WT Vif. The cells were treated with MG132 (5 μM) for 16-h before cell lysates were harvested. Immunoblots of cell lysates (upper three panels) and co-IP samples (lower two panels) probed for Flag-CBFβ, endogenous CBFβ, Vif, and tubulin (loading control) are shown. b Average immunoprecipitation efficiency of WT Vif with CBFβ mutants relative to WT CBFβ (set to 100%). Statistical significance was determined using t test; *P < 0.05. c The model depicts Vif (red) and CBFβ (cyan) adapted from PDB: 4N9F. The tripartite hydrophobic interaction of I55 (magenta) and F68 (magenta) of CBFβ and W5 (blue) of Vif are highlighted in black frame and a close-up of the highlighted residues is shown with the approximated distance between them in Å