Figure 6.

The type II receptor kinase activity is required in activin A-induced BMP signaling. (A) The overexpression of kinase-deficient ActR-IIA^K219R and ActR-IIB^K217R significantly downregulated activin A-induced BMP signaling via FOP ALK2^R206H. (B) The overexpression of kinase-deficient ActR-IIA^K219R and ActR-IIB^K217R significantly downregulated activin A-induced BMP signaling via ALK2^WT upon FKBP12 dissociation in HepG2BRA cells. (C) The overexpression of kinase-deficient BMPR-2^K230R downregulated activin A-induced BMP signaling via FOP ALK2^R206H and (D) via ALK2^WT upon FKBP12 dissociation. All the luciferase assays were conducted in the stably transfected BMP-responsive HepG2BRA cells. Results of the luciferase assay were represented as the mean relative luciferase units (RLU)  ±  SEM (n  =  3, * p < 0.05, ** p < 0.01).