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Structural model and functional significance of pH-dependent talin-actin binding for focal adhesion remodeling.

Srivastava, J, Barreiro, G, Groscurth, S, Gingras, A R, Goult, Benjamin T, Critchley, D R, Kelly, M J S, Jacobson, M P, Barber, D L (2008) Structural model and functional significance of pH-dependent talin-actin binding for focal adhesion remodeling. Proceedings of the National Academy of Sciences of the United States of America, 105 (38). pp. 14436-14441. ISSN 1091-6490. (doi:10.1073/pnas.0805163105) (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)

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. (Contact us about this Publication)
Official URL
http://dx.doi.org/10.1073/pnas.0805163105

Abstract

Actin filament binding by the focal adhesion (FA)-associated protein talin stabilizes cell-substrate adhesions and is thought to be rate-limiting in cell migration. Although F-actin binding by talin is known to be pH-sensitive in vitro, with lower affinity at higher pH, the functional significance of this pH dependence is unknown. Because increased intracellular pH (pH(i)) promotes cell migration and is a hallmark of metastatic carcinomas, we asked whether it increases FA remodeling through lower-affinity talin-actin binding. Talin contains several actin binding sites, but we found that only the COOH-terminal USH-I/LWEQ module showed pH-dependent actin binding, with lower affinity and decreased maximal binding at higher pH. Molecular dynamics simulations and NMR of this module revealed a structural mechanism for pH-dependent actin binding. A cluster of titratable amino acids with upshifted pK(a) values, including His-2418, was identified at one end of the five-helix bundle distal from the actin binding site. Protonation of His-2418 induces changes in the conformation and dynamics of the remote actin binding site. Structural analyses of a mutant talin-H2418F at pH 6.0 and 8.0 suggested changes different from the WT protein, and we confirmed that actin binding by talin-H2418F was relatively pH-insensitive. In motile fibroblasts, increasing pH(i) decreased FA lifetime and increased the migratory rate. However, expression of talin-H2418F increased lifetime 2-fold and decreased the migratory rate. These data identify a molecular mechanism for pH-sensitive actin binding by talin and suggest that FA turnover is pH-dependent and in part mediated by pH-dependent affinity of talin for binding actin.

Item Type: Article
DOI/Identification number: 10.1073/pnas.0805163105
Subjects: Q Science > QH Natural history > QH301 Biology
Divisions: Faculties > Sciences > School of Biosciences
Depositing User: Ben Goult
Date Deposited: 07 Aug 2014 15:39 UTC
Last Modified: 29 May 2019 12:52 UTC
Resource URI: https://kar.kent.ac.uk/id/eprint/42132 (The current URI for this page, for reference purposes)
Goult, Benjamin T: https://orcid.org/0000-0002-3438-2807
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