Talin at a glance.

Cell migration, growth and differentiation all require the assembly and disassembly of cellular junctions with the extracellular matrix (ECM). These large multiprotein complexes assemble around the integrin family of cell adhesion molecules (transmembrane αβ heterodimers) that are typically linked to the actin cytoskeleton, with the exception of integrin α6β4, which is coupled to intermediate filaments. Talin is one of several proteins that link the cytoplasmic domains of integrin β subunits to actin filaments (others include α-actinin, filamin, tensin, integrin-linked kinase, melusin and skelemin) (Critchley, 2004; Nayal et al., 2004). Moreover, binding of talin to β-integrin cytoplasmic domains triggers a conformational change in the αβ-integrin extracellular domain that increases its affinity for ECM proteins (Calderwood, 2004) and promotes the assembly of focal adhesions (FAs), cellECM junctions that are formed by cells in culture. However, studies in flies expressing mutant integrin alleles show that there is not a simple 1:1 relationship between integrins and talin in cell-ECM junctions, and there must be additional mechanisms that recruit talin to these sites (Devenport et al., 2007).