The purified recombinant FAT domain of the Focal Adhesion Kinase does not bind directly to recombinant Talin or MBD2 in vitro

Abstract

Controlled localization and activation of the focal adhesion kinase (FAK) functionally links adhesion, migration and survival of the cell. The C-terminal focal adhesion targeting (FAT) domain of FAK is an important regulator of the localization, activation and molecular associations of FAK. Here, we aimed to investigate the structural basis for how FAK FAT binds to Talin and MBD2, which were previously reported to be cytoplasmic and nuclear ligands, respectively. Using several biophysical methods with purified recombinantly expressed protein constructs, we failed to observe measurable interactions between FAT and either the Talin FERM domain or MBD2. We conclude that the association of FAT with these proteins requires additional factors or post-translational modifications not present in bacterially produced purified proteins.