FIGURE 7.
Gdf1 is needed for efficient signaling via Cripto or Cryptic but does not enhance binding of Nodal to soluble receptor Fc fusion proteins. A, induction of CAGA-luc by recombinant Nodal (gray) or purified Nodal·Gdf1 (black) in reporter cells expressing Cripto (top) or Cryptic (bottom). Western blot (WB) analysis of Fc-receptor fusion constructs and associated Nodal proteins following pulldown (PD) of Cripto-Fc (B) or Cryptic-Fc (C) fusion proteins using Gdf1(HA) is shown. D, induction of CAGA-luc by recombinant Nodal or Nodal·Gdf1(His6) following treatment of the reporter cells with siRNAs against ACVR2B or BMPR2. Western blot analysis of Fc-receptor fusion constructs and associated Nodal proteins following pulldown of ACVR1B-Fc (E) or Acvr2a-Fc and Acvr2b-Fc (F) fusion proteins using Gdf1(HA) is shown. In A and D, error bars represent S.D.