Fig 4.

Wild-type or GS domain mutant ALK2-mediated transcriptional activity may be facilitated by either full-length or short-isoform BMPRII or ACTRIIA. BRE-luciferase activity was restored in compound Bmpr2^−/−:Acvr2a^−/− cells following cotransfection of wild-type ALK2 or GS domain mutant ALK2^Q207D or ALK2^R206H in combination with wild-type BMPRII (A), BMPRII short isoform (SF) (B), or wild-type ACTRIIA (C). Following transfection, cells were incubated in the absence of serum for 24 h. Data are represented as means ± SEM (n = 4; *, P < 0.01; **, P < 0.001 [compared with luciferase expression in pcDNA-transfected cells]). Results shown are representative of 3 independent experiments.