High-resolution snapshots of the talin auto-inhibitory states suggest roles in cell adhesion and signaling.

Abstract

Talin regulates crucial cellular functions, including cell adhesion and motility, and affects human diseases. Triggered by mechanical forces, talin plays crucial roles in facilitating the formation of focal adhesions and recruiting essential focal adhesion regulatory elements such as vinculin. The structural flexibility allows talin to fine-tune its signaling responses. This study presents our 2.7 Å cryoEM structures of talin, which surprisingly uncovers several auto-inhibitory states. Contrary to previous suggestions, our structures reveal that (1) the first and last three domains are not involved in maintaining talin in its closed state and are mobile, (2) the talin F-actin and membrane binding domain are loosely attached and thus available for binding, and (3) the main force-sensing domain is oriented with its vinculin binding sites ready for release. These structural snapshots offer insights and advancements in understanding the dynamic talin activation mechanism, which is crucial for mediating cell adhesion.