FIGURE 7.

Trans-complementation assays of recombinant nephronectin fragments. A, 96-well microtiter plates were coated with LS/378–407 (closed squares), LS/378–393 (open squares), and GST (open triangles), washed with PBS, and then coated a second time with increasing concentrations of LS/395–407 lacking the RGD motif. The plates were subjected to integrin binding assays using 1 nm α8β1 integrin as described under “Experimental Procedures.” B, titration curves of α8β1 integrin bound to substrates coated with LS/378–393, followed by a second coating with LS/395–407 at 0 (diamonds), 1 (squares), 10 (triangles), and 100 nm (circles). Note that the affinities ofα8β1 integrin for LS/378–393 are synergistically enhanced by the presence of LS/395–407. C, microtiter plates were coated with 10 nm LS/378–393, washed with PBS, and then coated a second time with increasing concentrations of LS/395–407 (closed diamonds), LS/395–407 (E400A/E402A) (closed squares), and GST (open triangles). The plates were subjected to integrin binding assays using 1 nm α8β1 integrin as described under “Experimental Procedures.” The results represent the means of duplicate determinations.