Mechanotransmission and Mechanosensing of Human alpha-Actinin 1

Abstract

α-Actinins, a family of critical cytoskeletal actin-binding proteins that usually exist as anti-parallel dimers, play crucial roles in organizing the framework of the cytoskeleton through crosslinking the actin filaments, as well as in focal adhesion maturation. However, the molecular mechanisms underlying its functions are unclear. Here, by mechanical manipulation of single human α-actinin 1 using magnetic tweezers, we determined the mechanical stability and kinetics of the functional domains in α-actinin 1. Moreover, we identified the force-dependence of vinculin binding to α-actinin 1, with the demonstration that force is required to expose the high-affinity binding site for vinculin binding. Further, a role of the α-actinin 1 as molecular shock absorber for the cytoskeleton network is revealed. Our results provide a comprehensive analysis of the force-dependent stability and interactions of α-actinin 1, which sheds important light on the molecular mechanisms underlying its mechanotransmission and mechanosensing functions.

Endothelial Cell Mechanotransduction in the Dynamic Vascular Environment

“…[18] This molecular mechanism by which forces unravel proteins to expose cryptic binding sites and trigger enzymatic activity and intracellular signaling cascades is similar for α-actinin. [19] …”

The holdase function of Escherichia coli Hsp70 (DnaK) chaperone

“…This makes it possible to maintain the unfolded conformation at sufficiently high forces allowing chaperone binding, and switch to lower forces to investigate the effects of the chaperone on the protein refolding. We have recently demonstrated the use of this single-molecule assay in studying unfolding and refolding of several typical protein domains under force, such as Ig domains [27,28], α-helix bundles [29,30] and spectrin repeats [31] under force. We have also applied this approach to probe small molecule binding to unfolded polyprotein [32].…”

Reconstruction of Average Subtracted Tubular Regions (RASTR) Enables Structure Determination of Tubular Filaments by Cryo-EM

“…There are many examples of proteins that interact with helical polymers, actin-binding proteins by themselves run the range from A (a-actinin 25 ) to Z (Zyxin 26 ). When proteins decorate tubules, they can form complexes that are asymmetrical, preventing the use of helical symmetry for resolving the architecture.…”