Enables ATP binding activity and DNA binding activity. Involved in several processes, including negative regulation of cell-cell adhesion mediated by integrin; negative regulation of peptidyl-serine dephosphorylation; and regulation of actin filament organization. Acts upstream of or within isotype switching. Located in nucleus. Orthologous to human SWAP70 (switching B cell complex subunit SWAP70). [provided by Alliance of Genome Resources, Apr 2022]