FIGURE 5.

Kindlin-1 and -2 bind to the membrane-distal NPKY motif in β1A tails. A, the protein sequence for the cytoplasmic tail of human integrin β1A. Asterisks denote residues required for kindlin-1 and -2 binding. B-D, pulldown assays mapping the binding site on β1A tails for kindlin-1 and -2 binding. Lysates from CHO cells either untransfected or transiently expressing FLAG-tagged kindlin-1 or -2 were mixed with wild-type and mutant β1A tails and assessed for binding. The binding of kindlin-1 and -2 was quantified by densitometry, normalized to starting material loading, and then calculated relative to binding of wild-type β1A (means ± S.E.; n ≥ 3). E and F, bacterially purified GST-tagged kindlin-1 and -2 were examined for their ability to bind to β1A tail mutants. IB, immunoblot; WT, wild type.