Abstract

Actin plays several essential roles in cellular processes and is a vital component in the contractile apparatus. To accomplish its many cellular tasks, actin must interact with a wide range of other proteins in addition to self‐assembling into filaments. Characterization of these functional domains and localized binding regions on the actin monomer is therefore an important undertaking. Strategies for elucidating the many interaction sites include X‐ray diffraction, NMR and fluorescence spectroscopy, chemical modification, chemical cross‐linking, protein cleavage, and the study of sequence homologies between the many isotypes of actin. Based on these varied data, we discuss the possible spatial relationships between the interaction sites.