Kindlins: essential regulators of integrin signalling and cell–matrix adhesion

Abstract

Integrin‐mediated cell–ECM (extracellular matrix) adhesion is a fundamental process that controls cell behaviour. For correct cell–ECM adhesion, both the ligand‐binding affinity and the spatial organization of integrins must be precisely controlled; how integrins are regulated, however, is not completely understood. Kindlins constitute a family of evolutionarily conserved cytoplasmic components of cell–ECM adhesions that bind to β‐integrin cytoplasmic tails directly and cooperate with talin in integrin activation. In addition, kindlins interact with many components of cell–ECM adhesions—such as migfilin and integrin‐linked kinase—to promote cytoskeletal reorganization. Loss of kindlins causes severe defects in integrin signalling, cell–ECM adhesion and cytoskeletal organization, resulting in early embryonic lethality (kindlin‐2), postnatal lethality (kindlin‐3) and Kindler syndrome (kindlin‐1). It is therefore clear that kindlins, together with several other integrin‐proximal proteins, are essential for integrin signalling and cell–ECM adhesion regulation.