Fig. 4.

The Mcl-1 TMD immunoprecipitates Bok FL protein. (A) Bok FL and the VN Mcl-1 TMD were coexpressed in HCT116 cells. Immunoprecipitates were probed by Western blotting with anti-Bok and anti-c-myc antibodies. IgG nonrelated was used as negative antibody control. (B) The proapoptotic effect of the Bok TMD is partially inhibited by the presence of the Mcl-1 TMD, as measured by caspase 3/7 activity and cell toxicity assays (C) in HCT116 cells cotransfected with VN Bcl TMD constructs. Error bars represent the mean ± SEM, n = 3. **P < 0.01; ***P < 0.001. n.s., not significant. (D) Scheme of putative heterointeractions formed upon transfection of Mcl-1 TMD (Upper) or Bok TMD (Lower) in cells. Red squares highlight complexes that could be involved in cell death induction.