Figure 2.

Interaction of Medea with pathway-specific Smads. (A) FLAG-tagged Smad1 or FLAG-tagged Smad2 was introduced into COS cells with myc-tagged Medea in the absence or presence of the HA-tagged constitutively active type I receptor for BMP (BMPR-IB; QD) or TGF-β (TβR-I; TD). Interaction was detected by immunoprecipitation with anti-FLAG antibody followed by Western blotting with anti-myc antibody. The expression of Medea, Smad1, Smad2 and receptors was monitored by straight Western blotting with antibodies against the respective tags. (B) Association of Mad with Medea was examined in a similar experiment. FLAG-tagged Mad and myc-tagged Medea were expressed in COS cells in the absence or presence of constitutively active Tkv (Tkv-QD). The expression of each protein was monitored by straight Western blotting.