Figure 8. ActRIIA and BMPRII physically interact.

. Coimmunoprecipitation experiments were performed as in Figure 7. In all experiments, cells were transfected, cell surface proteins crosslinked, immunoprecipitation (IP) performed, crosslinks reversed, and Western blot (IB) performed as indicated. In some studies, cells were transfected with FLAG-endoglin as a positive control. Input lysate, post IP lysate, and IP samples are loaded as indicated. (A and B) ActRIIA precipitates with BMPRII. (C and D) ActRIIA kinase domain is dispensable for interaction with BMPRII. (E and F) BMPRII kinase activity and tail domain are dispensable for interaction with BMPRII. All data are from a representative experiment, repeated at least N = 5 separate times.