Proposed core component of the chromatin remodeling INO80 complex which is involved in transcriptional regulation, DNA replication and probably DNA repair. Involved in DNA double-strand break repair and UV-damage excision repair. Component of the chromatin remodeling INO80 complex; specifically part of a complex module associated with the helicase ATP-binding and the helicase C-terminal domain of INO80. Interacts with DDB1. Interacts with ACTR8; the interaction is observed in asynchronous (interphase) cells but not in metaphase-arrested cells indicative for a possible dissociation of the INO80 complex in mitotic cells. Predominantly nuclear but undergoes nucleo-cytoplasmic shuttling (PubMed:19014934). Localized to interphase nuclei, but not nucleoli; excluded from chromosomes as mitosis progresses (PubMed:18163988). Belongs to the actin family. ARP5 subfamily.