F-actin Bundle Sedimentation Assay

Bio Protoc. 2019 Nov 5;9(21):e3419. doi: 10.21769/BioProtoc.3419.

Abstract

Understanding the molecular mechanism governing the higher-order regulation of actin dynamics requires chemically-defined and quantitative assays. Recently, the membrane remodeling large GTPase, dynamin, has been identified as a new actin cross-linking molecule. Dynamin regulates actin cytoskeleton through binding to, self-assembling around, and aligning them into actin bundles. Here we utilize dynamin as an example and present a simple protocol to analyze the actin bundling activity in vitro. This protocol details the method for F-actin reconstitution as well as quantitative and qualitative analyses for actin bundling activity of dynamins. Measurement of the actin bundling activity of other actin-binding proteins may also be applied to this protocol with appropriate adjustments depending on the protein of interest.

Keywords: Actin bundle; Actin crosslinker; Dynamin; GTPase; Invadosome.