FIGURE 4.

BDD-fVIII binds to LRP1 clusters II and IV but not to cluster III. A, domain structure of LRP1. The extracellular chain contains four clusters of cysteine-rich ligand binding repeats (I–IV; red circles). An arrow shows the furin cleavage site. B, C, and D, increasing concentrations of clusters II (circles), III (squares), and IV (triangles) were incubated with microtiter wells coated with BDD-fVIII (B), BSA (C), or RAP (D). Following incubation and washing, the amount of clusters bound to each well was measured. The experiments were repeated twice, each in duplicate, and a representative experiment is shown in which replicate values are plotted.