Probably involved in transcription regulation via its interaction with the INO80 complex, a chromatin remodeling complex. Exhibits low basal ATPase activity, and unable to polymerize. Strongly prefer nucleosomes and H3-H4 tetramers over H2A-H2B dimers, suggesting it may act as a nucleosome recognition module within the complex (By similarity). Component of the chromatin remodeling Ino80 complex. Exists as monomers and dimers, but the dimer is most probably the biologically relevant form required for stable interactions with histones that exploits the twofold symmetry of the nucleosome core (By similarity). Belongs to the actin family.