FIGURE 1.

Kindlin-1 and -2 bind directly to β1A integrin tails. A, schematic diagram of the human kindlin-1 and -2 proteins and fragments generated. The shaded regions correspond to the predicted FERM domain. The two upper lines signify a portion of the FERM domain with high similarity to the FERM domain of talin. The white PH region corresponds to a region with high homology to Pleckstrin homology domains. B, pulldown assays using recombinant β1A tails mixed with CHO cell lysates containing FLAG-tagged kindlin-1 or -2. Binding of kindlins, endogenous talin (positive control), and the major vault protein (negative control), was assessed by Western blotting. αIIb tails serve as controls for binding specificity to the β tails. Loading of each tail protein was judged by protein staining. The 10% lanes represent 10% of the starting material in the binding assay. C and D, direct binding of GST-tagged kindlin-1 and -2 to β1A but not αIIb tails. IB, immunoblot.