FIGURE 2.

Binding activities of α8β1 integrin toward nephronectin and other RGD-containing proteins. A, 96-well microtiter plates were coated with various RGD-containing proteins (10 nm) and then incubated with α8β1 integrin (10 nm) in the presence of 1 mm Mn²⁺. FN, fibronectin; VN, vitronectin; Fbg, fibrinogen; NN, nephronectin. Bound integrins were quantified as described under “Experimental Procedures.” The amounts of integrin bound in the presence of 10 mm EDTA were taken as negative controls, and subtracted as backgrounds. The results represent the mean ± S.D. of triplicate determinations. B, titration curves of recombinant α8β1 integrin bound to fibronectin (diamonds), vitronectin (squares), fibrinogen (triangles), and nephronectin (circles). Microtiter plates coated with individual proteins (10 nm) were incubated with increasing concentrations of α8β1 in the presence of 1 mm Mn²⁺, followed by quantification of the bound integrins under “Experimental Procedures.” The results represent the means of duplicate determinations.