Component of the SWR1 complex which mediates the ATP-dependent exchange of histone H2A for the H2A variant H2A.F/Z leading to transcriptional regulation of selected genes (e.g. FLC) by chromatin remodeling. Binds to the promoter region of FLC chromatin. Required for the activation of FLC and FLC/MAF genes expression to levels that inhibit flowering, through both histone H3 and H4 acetylation and methylation mechanisms. Involved in several developmental processes including organization of plant organs, leaves formation, flowering time repression, and fertility. Modulates photoperiod-dependent epidermal leaves cell development; promotes cell division in long days, and cell expansion/division in short days. May be involved in the regulation of pathogenesis-related proteins (PRs). Component of the SWR1 chromatin-remodeling complex composed of at least ARP6/ESD1/SUF3, PIE1, SWC6, SWC2 and H2AZs (HTA8, HTA9, HTA11). Interacts directly with SWC6/SEF and PIE1. Also interacts with H2A.F/Z proteins. Localized in the nucleus during the interphase, but is released into the cytoplasm during the mitotic phase (PubMed:16141450). Associated to heterochromatin (PubMed:16141450). Localized at the nuclear periphery when interacting with SWC6 (PubMed:16155178, PubMed:17470967). Mostly expressed in flowers, and, to a lower extent, in seedlings, shoot apex, stems, siliques, seeds, and roots (at protein level). Early flowering, leaf serration, production of extra petals and weak apical dominance. Belongs to the actin family. ARP6 subfamily.