Figure 3.

Determination of the domains in LEF1 that mediate association with Smad3. (A) A schematic representation of mutant versions of LEF1 are shown. The β-catenin binding domain (β-cat BD) and the HMG box are marked. The location of the three helices within the HMG box (overline) and the MH1- and MH2-binding domains (BD; underline) are indicated. A summary of the interaction of LEF1 with FL, MH1, and MH2 domains of Smad3 is shown (right). (B–D) Interaction of wild-type or mutant LEF1 with bacterially expressed FL, MH1, or MH2 domains of Smad3. COS-1 cells were transfected with wild-type or mutant versions of LEF1 and cell lysates incubated with bacterially expressed GST fusion proteins. The associated LEF1 was visualized by anti-HA immunoblotting. Total LEF1 protein expression was confirmed by immunoblotting (input).