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

Michèle Moes, Sophie Rodius, Stacey J. Coleman, Susan J. Monkley, Erik Goormaghtigh, Laurent Tremuth, Corinne Kox, Patrick P.G. Van Der Holst, David R. Critchley, Nelly Kieffer*

*Corresponding author for this work

Research output: Contribution to journalArticleResearchpeer-review

51 Citations (Scopus)

Abstract

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

Original languageEnglish
Pages (from-to)17280-17288
Number of pages9
JournalJournal of Biological Chemistry
Volume282
Issue number23
DOIs
Publication statusPublished - 8 Jun 2007
Externally publishedYes

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