Measuring molecular rupture forces between single actin filaments and actin-binding proteins
- 8 July 2008
- journal article
- research article
- Published by Proceedings of the National Academy of Sciences in Proceedings of the National Academy of Sciences of the United States of America
- Vol. 105 (27), 9221-9226
- https://doi.org/10.1073/pnas.0706124105
Abstract
Actin-binding proteins (ABPs) regulate the assembly of actin filaments (F-actin) into networks and bundles that provide the structural integrity of the cell. Two of these ABPs, filamin and α-actinin, have been extensively used to model the mechanical properties of actin networks grown in vitro; however, there is a lack in the understanding of how the molecular interactions between ABPs and F-actin regulate the dynamic properties of the cytoskeleton. Here, we present a native-like assay geometry to test the rupture force of a complex formed by an ABP linking two quasiparallel actin filaments. We readily demonstrate the adaptability of this assay by testing it with two different ABPs: filamin and α-actinin. For filamin/actin and α-actinin/actin, we measured similar rupture forces of 40–80 pN for loading rates between 4 and 50 pN/s. Both ABP unfolding and conformational transition events were observed, demonstrating that both are important and may be a significant mechanism for the temporal regulation of the mechanical properties of the actin cytoskeleton. With this modular, single-molecule assay, a wide range of ABP/actin interactions can be studied to better understand cytoskeletal and cell dynamics.Keywords
This publication has 56 references indexed in Scilit:
- Bending Dynamics of Fluctuating Biopolymers Probed by Automated High-Resolution Filament TrackingBiophysical Journal, 2007
- Reversible stress softening of actin networksNature, 2007
- Cytoskeletal polymer networks: The molecular structure of cross-linkers determines macroscopic propertiesProceedings of the National Academy of Sciences of the United States of America, 2006
- Interlaced Optical Force-Fluorescence Measurements for Single Molecule BiophysicsBiophysical Journal, 2006
- The consensus mechanics of cultured mammalian cellsProceedings of the National Academy of Sciences of the United States of America, 2006
- Mechanics of actomyosin bonds in different nucleotide states are tuned to muscle contractionProceedings of the National Academy of Sciences of the United States of America, 2006
- Structural Dynamics of α-Actinin-Vinculin InteractionsMolecular and Cellular Biology, 2005
- Optical trappingReview of Scientific Instruments, 2004
- Analysis of filamin and α‐actinin binding to actin by the stopped flow methodFEBS Letters, 1993
- Structure of macrophage actin-binding protein molecules in solution and interacting with actin filamentsJournal of Molecular Biology, 1981