Fig. 4: Mutation of the C1 dimer interface disrupts the ALK2/BMPR2 heterodimeric kinase complex in solution.

a The C1 dimer with a zoomed in view of the interface showing positions of the charged residues within the C-lobes of the BMPR2 and ALK2 kinases involved in electrostatic interactions. b Overlaid size-exclusion chromatograms showing elution of the ALK2^KD/BMPR2^KD complex equilibrated in buffers containing the indicated increasing NaCl concentrations. c Nomenclature of the mutations introduced into the ALK2^KD and BMPR2^KD constructs to investigate the importance of the C1 dimer interface for ALK2^KD/BMPR2^KD complex formation in solution is shown at the top. Bottom panels show size-exclusion chromatograms of the ALK2^KD/BMPR2^KD complexes carrying the indicated mutations (red traces for BMPR2^KD mutations and blue traces for ALK2^KD mutations) overlaid on the chromatogram obtained for the wild-type ALK2^KD/BMPR2^KD complex.