Derivation of Actin‐Binding Peptides from a Cofilin Scaffold: A Rational Approach

Abstract

Actin‐binding peptides and proteins have numerous applications in the control and monitoring of cellular dynamics. This is effectively demonstrated by the wide usage of protein fusions containing the actin‐binding peptide LifeAct and fluorescent proteins for live cell imaging. Despite their popularity, there remains a need for a new generation of actin‐binding probes that are largely orthogonal to cellular processes. We propose that this need could be met by a rational deconstructive approach to well‐characterized actin‐binding peptides such as cofilin. In this work, we report on such an effort that uses structural information about the cofilin‐actin binding interface as a guide for the selection and design of cofilin‐derived peptide sequences (COFPEP). We describe the ability of these peptides to label cytoskeletal structures in live and fixed cells, and further detail methods for their improvement via rational design methods. Finally, we investigate whether these cofilin‐derived fragments can inhibit the formation of cofilin‐actin clusters and rods formed in cells undergoing energetic stress. We postulate that peptides with the ability to disrupt stress‐induced cofilin‐actin structures may have applications in studies of brain ischemia and neurodegenerative disease.