A conserved lipid-binding loop in the kindlin FERM F1 domain is required for kindlin-mediated αIIbβ3 integrin coactivation

Bouaouina, Mohamed and Goult, Benjamin T and Huet-Calderwood, Clotilde and Bate, Neil and Brahme, Nina N and Barsukov, Igor L and Critchley, David R and Calderwood, David A (2012) A conserved lipid-binding loop in the kindlin FERM F1 domain is required for kindlin-mediated αIIbβ3 integrin coactivation. The Journal of biological chemistry, 287 (10). pp. 6979-6990. ISSN 1083-351X. (doi:https://doi.org/10.1074/jbc.M111.330845) (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.M111.330845

Abstract

The activation of heterodimeric integrin adhesion receptors from low to high affinity states occurs in response to intracellular signals that act on the short cytoplasmic tails of integrin β subunits. Binding of the talin FERM (four-point-one, ezrin, radixin, moesin) domain to the integrin β tail provides one key activation signal, but recent data indicate that the kindlin family of FERM domain proteins also play a central role. Kindlins directly bind integrin β subunit cytoplasmic domains at a site distinct from the talin-binding site, and target to focal adhesions in adherent cells. However, the mechanisms by which kindlins impact integrin activation remain largely unknown. A notable feature of kindlins is their similarity to the integrin-binding and activating talin FERM domain. Drawing on this similarity, here we report the identification of an unstructured insert in the kindlin F1 FERM domain, and provide evidence that a highly conserved polylysine motif in this loop supports binding to negatively charged phospholipid head groups. We further show that the F1 loop and its membrane-binding motif are required for kindlin-1 targeting to focal adhesions, and for the cooperation between kindlin-1 and -2 and the talin head in αIIbβ3 integrin activation, but not for kindlin binding to integrin β tails. These studies highlight the structural and functional similarities between kindlins and the talin head and indicate that as for talin, FERM domain interactions with acidic membrane phospholipids as well β-integrin tails contribute to the ability of kindlins to activate integrins.

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 16:05 UTC
Last Modified:	30 Mar 2015 10:54 UTC
Resource URI:	https://kar.kent.ac.uk/id/eprint/42115 (The current URI for this page, for reference purposes)