Fig. 3.

Wnt1/sFRP-1 binding to LRP6 E1 domain is blocked by CKP. (A) Binding of Wnt1/sFRP-1 to different domains of LRP6. Fit to a 1:1 binding model is indicated (red). Sensogram plots for competition experiments between Wnt1/sFRP-1 and Lr-EET-3.5 (B) SOST (C) and FabYW210 (D) are shown. The surface was coated with LRP6-E1-E2. The surface was then saturated with competitor or treated with buffer only (first arrow), and then immediately afterward either Wnt1/sFRP-1 (green), competitor (red), or a mixture of competitor and Wnt1/sFRP-1 (blue) was injected. The resulting binding signal of Wnt1/sFRP-1 in the presence or absence of competitors was inspected manually. Note that the binding signal of Lr-EET-3.5 alone is not visible due to very low molecular weight compared to other reagents.