Structural determinants of integrin binding to the talin rod.

Gingras, Alexandre R and Ziegler, Wolfgang H and Bobkov, Andrey A and Joyce, M Gordon and Fasci, Domenico and Himmel, Mirko and Rothemund, Sven and Ritter, Anett and Grossmann, J Günter and Patel, Bipin and Bate, Neil and Goult, Benjamin T and Emsley, Jonas and Barsukov, Igor L and Roberts, Gordon C K and Liddington, Robert C and Ginsberg, Mark H and Critchley, David R (2009) Structural determinants of integrin binding to the talin rod. The Journal of biological chemistry, 284 (13). pp. 8866-8876. ISSN 0021-9258. (doi:https://doi.org/10.1074/jbc.M805937200) (The full text of this publication is not currently available from this repository. You may be able to access a copy if URLs are provided)

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Official URL
http://dx.doi.org/10.1074/jbc.M805937200

Abstract

The adaptor protein talin serves both to activate the integrin family of cell adhesion molecules and to couple integrins to the actin cytoskeleton. Integrin activation has been shown to involve binding of the talin FERM domain to membrane proximal sequences in the cytoplasmic domain of the integrin beta-subunit. However, a second integrin-binding site (IBS2) has been identified near the C-terminal end of the talin rod. Here we report the crystal structure of IBS2 (residues 1974-2293), which comprises two five-helix bundles, "IBS2-A" (1974-2139) and "IBS2-B" (2140-2293), connected by a continuous helix with a distinct kink at its center that is stabilized by side-chain H-bonding. Solution studies using small angle x-ray scattering and NMR point to a fairly flexible quaternary organization. Using pull-down and enzyme-linked immunosorbent assays, we demonstrate that integrin binding requires both IBS2 domains, as does binding to acidic phospholipids and robust targeting to focal adhesions. We have defined the membrane proximal region of the integrin cytoplasmic domain as the major binding region, although more membrane distal regions are also required for strong binding. Alanine-scanning mutagenesis points to an important electrostatic component to binding. Thermal unfolding experiments show that integrin binding induces conformational changes in the IBS2 module, which we speculate are linked to vinculin and membrane binding.

Item Type: Article
Subjects: Q Science > QH Natural history > QH301 Biology
Divisions: Faculties > Sciences > School of Biosciences
Depositing User: Ben Goult
Date Deposited: 07 Aug 2014 15:36 UTC
Last Modified: 07 May 2015 09:19 UTC
Resource URI: https://kar.kent.ac.uk/id/eprint/42131 (The current URI for this page, for reference purposes)
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