Measuring molecular rupture forces between single actin filaments and actin-binding proteins

Jorge M. Ferrer, Hyungsuk Lee, Jiong Chen, Benjamin Pelz, Fumihiko Nakamura, Roger D. Kamm, Matthew J. Lang

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170 Citations (Scopus)


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.

Original languageEnglish
Pages (from-to)9221-9226
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number27
Publication statusPublished - 2008 Jul 8

All Science Journal Classification (ASJC) codes

  • General


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