Talin contains three similar vinculin-binding sites predicted to form an amphipathic helix

Abstract

Using recombinant talin polypeptides and an SDS\PAGE-blot overlay assay, we have previously identified three regions of talin that are involved in binding to vinculin [Gilmore, Wood, Ohanian, Jackson, Patel, Rees, Hynes and Critchley (1993) J. Cell Biol. 122, 337-347]. We have confirmed these observations by using a yeast two-hybrid assay and shown that talin residues 498-656, 852-950 and 1929-2029 are each capable of binding to vinculin residues 1-258. We have further defined the three vinculin-binding sites in talin to residues 607-636, 852-876 and 1944-1969 ; alignment of these sequences shows 59 % similarity, although there are only two identical residues. Predictions of secondary structure indicate that this vinculin-binding motif forms an amphipathic α-helix. The hydrophobic face of helix 607-636 contains three aligned leucines (residues 608, 615 and 622), which show conservative substitutions in the other two

Force-induced activation of Talin and its possible role in focal adhesion mechanotransduction

“…Interestingly, the RQK and ER handles or similar motifs are ubiquitous in talin rod VBSs suggesting this mechanism as a general force-induced VBS activation mechanism of talin. For example, VBS2 (residues 852-876) contains sequences (KILAD and KMVEAAK) (Bass et al, 1999) similar to ER (ELLR) and RQK (RPLLQAAK) handles of VBS1 in terms of charges. Also, VBS3 (residues 1944-1969) contains (KKELIECARRVSEK) (Bass et al, 1999).…”

“…For example, VBS2 (residues 852-876) contains sequences (KILAD and KMVEAAK) (Bass et al, 1999) similar to ER (ELLR) and RQK (RPLLQAAK) handles of VBS1 in terms of charges. Also, VBS3 (residues 1944-1969) contains (KKELIECARRVSEK) (Bass et al, 1999). Charged and polar residues are shown in bold face to highlight the similarity with ER and RQK sequences of VBS1.…”

“…vinculin and talin), hence promoting focal adhesion assembly (Ling et al, 2002). The talin rod can bind to b-integrin (Xing et al, 2001) and F-actin (Hemmings et al, 1996), and contains 11 vinculin-binding sites (VBSs), each of which is an amphipathic a-helix (Bass et al, 1999;Gingras et al, 2006). Vinculin is a cytoplasmic protein that may function as a structural reinforcement.…”

Characterization of an Actin-binding Site within the Talin FERM Domain

“…21 The talin head also contains binding sites for (i) layilin, a C-type lectin that colocalizes with talin in membrane ruffles, 22 (ii) the type 1g neuronal isoform of phosphatidylinositol 4-phosphate 5-kinase (PIPkin), 23,24 which is important in focal adhesion assembly, and (iii) FAK, 25 which is implicated in stimulating focal adhesion turnover and cell migration. 26 The large C-terminal rod domain of talin contains a second integrin-binding site, 27 three vinculin-binding sites, 28 and is able to bind F-actin. [29][30][31][32] The talin molecule is comprised of two subunits that are likely arranged in an antiparallel manner, 33,34 which probably explains why it can cross-link actin into networks and bundles.…”

Disruption of thetalin gene arrests mouse development at the gastrulation stage

“…The globular N-terminal region (residues 1-435) contains binding sites for integrins (Calderwood et al, 1999), layilin, and the protein tyrosine kinase pp125FAK (Borowsky and Hynes, 1998), whereas the C-terminal region (2270-2541) contains an actin-binding site (Hemmings et al, 1996;McCann and Craig, 1997). The central rod domain contains three binding sites for the cytoskeletal protein vinculin (residues 607-636, 852-876, and1944 -1969;Bass et al, 1999), which can also bind F-actin (Huttelmaier et al, 1997). That talin can exist as an antiparallel dimer (Isenberg and Goldmann, 1998) probably explains why it cross-links actin filaments, although evidence for two other actin-binding sites in talin has been presented (Hemmings et al, 1996).…”