The binding interface of kindlin-2 and ILK involves Asp344/Asp352/Thr356 in kindlin-2 and Arg243/Arg334 in ILK

Abstract

Focal adhesion (FA) proteins, kindlin-2 and integrin-linked kinase (ILK), regulate cell adhesion and migration. ILK interacts with and promotes kindlin-2 targeting to FAs. Leu353 and Leu357 in kindlin-2 have been reported to be important for the interaction between kindlin-2 and ILK. However, the binding interface between kindlin-2 and ILK remains unclear. Using molecular modeling and molecular dynamics simulations, we show that Asp344, Asp352, and Thr356 in kindlin-2 and Arg243 and Arg334 in ILK kinase domain (KD) are important in kindlin-2/ILK complex formation. Mutations that disrupt these interactions abrogate kindlin-2 and ILK colocalization in HeLa cells. The interactions are direct based on data from pull-down assays using purified recombinant kindlin-2 F2-pleckstrin homology and ILK KDs. These data provide additional insights into the binding interface between kindlin-2 and ILK.