TLN1

Talin-1 is a protein that in humans is encoded by the TLN1 gene. Talin-1 is ubiquitously expressed, and is localized to costamere structures in cardiac and skeletal muscle cells, and to focal adhesions in smooth muscle and non-muscle cells. Talin-1 functions to mediate cell-cell adhesion via the linkage of integrins to the actin cytoskeleton and in the activation of integrins. Altered expression of talin-1 has been observed in patients with heart failure, however no mutations in TLN1 have been linked with specific diseases.

Structure

Human talin-1 is 270.0 kDa molecular weight and 2541 amino acids. The N-terminal region of talin-1 is ~50 kDa in size and homologous to members of the ERM protein family which have a globular FERM domain (residues 86-400) that links the actin cytoskeleton to adhesion proteins. In addition to F-actin, the N-terminal region of talin-1 binds layilin,β1- and β3-integrin, and focal adhesion kinase. Talin-1 N-terminal region also binds acidic phospholipids for insertion into lipid bilayers. The rod domain (>200 kDa) has considerable flexibility and houses a conserved actin binding site, three vinculin binding sites, and also has an additional integrin binding site, termed IBS2. The head and rod domains are connected by an unstructured linker region (residues 401-481), which houses several sites of phosphorylation, as well as protease cleavage. Talin-1 can homodimerize in an antiparallel fashion, however, talin-1 and its closely related counterpart, talin-2 do not form heterodimers.