Fig. 3: Ponatinib induces symmetrical BRAF dimers and promotes BRAF complexes in cells.
a The BRAFV600E/PON symmetrical dimer structure. The dimer is viewed along its twofold axis with two protomers in silver and green ribbon representations. PON bound to each protomer is shown in orange sticks/molecular surface. The αC-helix of each protomer is illustrated in magenta. b The αC-helix of BRAFV600E/PON complex adopts a αC-CENTRE position. Structural superposition of BRAF protomer structures in ribbon representation showing that αC-helix of BRAF-PON structure (magenta) lies between typical αC-OUT position observed in BRAF–Vemurafenib complex (cyan, PDB 3OG7) and αC-IN position in MEK-bound BRAF (gold, PDB 4MNE). Protein parts were omitted for clarity. c Various cell lines expressing BRAFV600E or RASMUT/BRAFWT were left untreated or treated with 1 or 5 μM Ponatinib for 1 h. Cells were then collected, assayed for CRAF by immunoprecipitation and immunoblot with the indicated antibodies for monitoring BRAF/CRAF heterodimerization and activation of ERK signaling. d Similar analysis to c assayed for MEK by immunoprecipitation and immunoblot with the indicated antibodies for monitoring BRAF/MEK complex formation. Data are representative of n = 3 independent experiments. Source data are provided as a Source Data file.
