The integrin binding site 2 (IBS2) in the talin rod domain is essential for linking integrin beta subunits to the cytoskeleton.

摘要: Talin1 is a large cytoskeletal protein that links integrins to actin filaments through two distinct integrin binding sites, one present in the talin head domain (IBS1) necessary for activation and second (IBS2) we have previously mapped residues 1984-2113 (fragment J) of rod (1 Tremuth, L., Kreis, S., Melchior, C., Hoebeke, J., Ronde, P., Plancon, Takeda, K., Kieffer, N. (2004) J. Biol. Chem. 279, 22258-22266), but whose functional role still elusive. Using bioinformatics cell biology approach, determined minimal structure IBS2 show this site corresponds 23 located α helix 50 (residues 2077-2099). Alanine mutation 2 highly conserved (L2094A/I2095A) within helix, which disrupted α-helical as demonstrated by infrared spectroscopy limited trypsin proteolysis, was sufficient prevent vivo fragment J targeting αIIbβ3 focal adhesions inhibit vitro association shown an pulldown assay. Moreover, expression full-length mouse green fluorescent protein-talin LI/AA mutant talin1-/- cells unable rescue inability these assemble (in contrast wild type) despite presence IBS1. Our data provide first direct evidence essential link cytoskeleton.