Publications

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6 Publications visible to you, out of a total of 6

Abstract (Expand)

The talin-vinculin axis is a key mechanosensing component of cellular focal adhesions. How talin and vinculin respond to forces and regulate one another remains unclear. By combining single molecule magnetic tweezer experiments, Molecular Dynamics simulations, actin bundling assays, and adhesion assembly experiments in live cells, we here discover a two-ways allosteric network within vinculin as a regulator of the talin-vinculin interaction. We directly observe a maturation process of vinculin upon talin binding which reinforces the binding to talin at a rate of 0.03 s−1. This allosteric transition can compete with force-induced dissociation of vinculin from talin only at 7-10 pN. Mimicking the allosteric activation by mutation yields a vinculin molecule that bundles actin and localizes to focal adhesions in a force-independent manner. Hence, the allosteric switch confines talin-vinculin interactions and focal adhesion build-up to intermediate force levels. The ‘allosteric vinculin mutant’ is a valuable molecular tool to further dissect the mechanical and biochemical signalling circuits at focal adhesions and elsewhere.

Authors: Florian Franz, Rafael Tapia-Rojo, Sabina Winograd-Katz, Rajaa Boujemaa-Paterski, Wenhong Li, Tamar Unger, Shira Albeck, Camilo Aponte-Santamaría, Sergi Garcia-Manyes, Ohad Medalia, Benjamin Geiger, Frauke Gräter

Date Published: 18th Jul 2023

Publication Type: Journal

Abstract (Expand)

Focal adhesions (FAs) mediate the interaction of the cytoskeleton with the extracellular matrix in a highly dynamic fashion. Talin is a central regulator, adaptor protein, and mechano-sensor of FA complexes. For recruitment and firm attachment at FAs, talin’s N-terminal FERM domain binds to phosphatidylinositol 4,5-bisphosphate (PIP2)-enriched membranes. A newly published autoinhibitory structure of talin-1, where the known PIP2 interaction sites are covered up, lead us to hypothesize that a hitherto less examined loop insertion of the FERM domain acts as an additional and initial site of contact. We evaluated direct interactions of talin-1 with a PIP2 membrane by means of atomistic molecular dynamics simulations. We show that this unstructured, 33-residue-long loop strongly interacts with PIP2 and can facilitate further membrane contacts, including the canonical PIP2 interactions, by serving as a flexible membrane anchor. Under force as present at FAs, the extensible FERM loop ensures talin maintains membrane contacts when pulled away from the membrane by up to 7 nm. We identify key basic residues of the anchor mediating the highly dynamic talin-membrane interaction. Our results put forward an intrinsically disordered loop as a key and highly adaptable PIP2 recognition site of talin and potentially other PIP2-binding mechano-proteins.

Authors: Jannik Buhr, Florian Franz, Frauke Gräter

Date Published: 21st Feb 2023

Publication Type: Journal

Abstract

hts into the mechanism governing the shear thinning effects observed in Nafion solutions, through the use of non-equilibrium, coarse-grained, molecular dynamic simulations.

Authors: Nicholas Michelarakis, Florian Franz, Konstantinos Gkagkas, Frauke Gräter

Date Published: 24th Nov 2021

Publication Type: Journal

Abstract (Expand)

Single-molecule force spectroscopy and classical molecular dynamics are natural allies. Recent advances in both experiments and simulations have increasingly facilitated a direct comparison of SMFS and MD data, most importantly by closing the gap between time scales, which has been traditionally at least 5 orders of magnitudes wide. In this review, we will explore these advances chiefly on the computational side. We focus on protein dynamics under force and highlight recent studies that showcase how lower loading rates and more statistics help to better interpret previous experiments and to also motivate new ones. At the same time, steadily increasing system sizes are used to mimic more closely the mechanical environment in the biological context. We showcase some of these advances on atomistic and coarse-grained scale, from asymmetric membrane tension to larger (multidomain/multimeric) protein assemblies under force.

Authors: Florian Franz, Csaba Daday, Frauke Gräter

Date Published: 1st Apr 2020

Publication Type: Journal

Abstract

Not specified

Authors: Florian Franz, Camilo Aponte-Santamaría, Csaba Daday, Vedran Miletić, Frauke Gräter

Date Published: 2018

Publication Type: Journal

Abstract

Not specified

Authors: Andreas Fetzer, Jasmin Metzger, Darko Katic, Keno März, Martin Wagner, Patrick Philipp, Sandy Engelhardt, Tobias Weller, Sascha Zelzer, Alfred M. Franz, Nicolai Schoch, Vincent Heuveline, Maria Maleshkova, Achim Rettinger, Stefanie Speidel, Ivo Wolf, Hannes Kenngott, Arianeb Mehrabi, Beat P. Müller-Stich, Lena Maier-Hein, Hans-Peter Meinzer, Marco Nolden

Date Published: 25th Mar 2016

Publication Type: Journal

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