Subcellular Localization of Talin Is Regulated by Inter-domain Interactions

Department of Medicine, University of California, San Diego, La Jolla, California 92093-0726, USA.
Journal of Biological Chemistry (Impact Factor: 4.57). 02/2012; 287(17):13799-812. DOI: 10.1074/jbc.M112.341214
Source: PubMed


Talin, which is composed of head (THD) and rod domains, plays an important role in cell adhesion events in diverse species
including most metazoans and Dictyostelium discoideum. Talin is abundant in the cytosol; however, it mediates adhesion by associating with integrins in the plasma membrane where
it forms a primary link between integrins and the actin cytoskeleton. Cells modulate the partitioning of talin between the
plasma membrane and the cytosol to control cell adhesion. Here, we combine nuclear magnetic resonance spectroscopy (NMR) with
subcellular fractionation to characterize two distinct THD-rod domain interactions that control the interaction of talin with
the actin cytoskeleton or its localization to the plasma membrane. An interaction between a discrete vinculin-binding region
of the rod (VBS1/2a; Tln1(482–787)), and the THD restrains talin from interacting with the plasma membrane. Furthermore, we
show that vinculin binding to VBS1/2a results in talin recruitment to the plasma membrane. Thus, we have structurally defined
specific inter-domain interactions between THD and the talin rod domain that regulate the subcellular localization of talin.

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Available from: Ben Goult, Nov 11, 2015
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    • "Among other highly ranked traces, K295 is involved in Talin–Actin binding, K364 in inter-domain interactions (Banno et al., 2012), F370 in Integrin activation (de Pereda et al., 2005), D372 in Talin localization in cells (Anthis et al., 2009), I356 in Integrin activation (Barsukov et al., 2003) and G394 in auto-inhibition of Talin Goksoy et al., 2008 (Fig. 7). Merlin (Neurofibromatosis-2) was second protein considered for ETA with Kindlins and Homo sapiens Merlin structure (PDB ID 3U8Z) (Yogesha et al., 2011) was used for structural mapping. "
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    ABSTRACT: Kindlin proteins represent a novel family of evolutionarily conserved FERM domain containing proteins (FDCPs) and are members of B4.1 superfamily. Kindlins consist of three conserved protein homologs in vertebrates: Kindlin-1, Kindlin-2 and Kindlin-3. All three homologs are associated with focal adhesions and are involved in integrin activation. FERM domain of each Kindlin is bipartite and plays a key role in integrin activation. A single ancestral Kindlin protein can be traced back to earliest metazoans, e.g., to Parazoa. This protein underwent multiple rounds of duplication in vertebrates, leading to the present Kindlin family. In this study, we trace phylogenetic and evolutionary history of Kindlin FERM domain with respect to FERM domain of other FDCPs. We show that FERM domain in Kindlin homologs is conserved among Kindlins but amount of conservation is less in comparison with FERM domain of other members in B4.1 superfamily. Furthermore, insertion of Pleckstrin Homology like domain in Kindlin FERM domain has important evolutionary and functional consequences. Important residues in Kindlins are traced and ranked according to their evolutionary significance. The structural and functional significance of high ranked residues is highlighted and validated by their known involvement in Kindlin associated diseases. In light of these findings, we hypothesize that FERM domain originated from a proto-Talin protein in unicellular or proto-multicellular organism and advent of multi-cellularity was accompanied by burst of FDCPs, which supported multi-cellularity functions required for complex organisms. This study helps in developing a better understanding of evolutionary history of FERM domain of FDCPs and the role of FERM domain in metazoan evolution.
    Full-text · Article · Aug 2014 · Molecular Phylogenetics and Evolution
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    • "The vinculin head domain was expressed and purified as reported previously15. The N-terminal His-tagged and C-terminal biotinylated R1–R3 (residue 482–911) and the R1–R3 IVVI mutant were expressed and purified as reported previously32. "
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    ABSTRACT: The force-dependent interaction between talin and vinculin plays a crucial role in the initiation and growth of focal adhesions. Here we use magnetic tweezers to characterise the mechano-sensitive compact N-terminal region of the talin rod, and show that the three helical bundles R1-R3 in this region unfold in three distinct steps consistent with the domains unfolding independently. Mechanical stretching of talin R1-R3 enhances its binding to vinculin and vinculin binding inhibits talin refolding after force is released. Mutations that stabilize R3 identify it as the initial mechano-sensing domain in talin, unfolding at ∼5 pN, suggesting that 5 pN is the force threshold for vinculin binding and adhesion progression.
    Full-text · Article · Apr 2014 · Scientific Reports
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    • "A structural model of fulllength talin, derived from the combination of crystallographic data and electron microscopy reconstruction, suggests that both the head and the C-terminal ABD are masked in the dimeric inactive talin (Goult et al., 2013a). In the inactive state, F2 and F3 must be released from autoinhibitory contacts with the R1-R2 and R9 domains of the rod respectively (Banno et al., 2012; Goult et al., 2009) (Fig. 3A). The mechanism by which talin is initially activated is still unclear. "
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    ABSTRACT: Focal adhesions are clusters of integrin transmembrane receptors that mechanically couple the extracellular matrix to the actin cytoskeleton during cell migration. Focal adhesions sense and respond to variations in force transmission along a chain of protein-protein interactions linking successively actin filaments, actin binding proteins, integrins and the extracellular matrix to adapt cell-matrix adhesion to the composition and mechanical properties of the extracellular matrix. This review focuses on the molecular mechanisms by which actin binding proteins integrate actin dynamics, mechanotransduction and integrin activation to control force transmission in focal adhesions.
    Full-text · Article · Nov 2013 · European journal of cell biology
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