Has both helicase and E3 ubiquitin ligase activities. Possesses intrinsic ATP-dependent nucleosome-remodeling activity. This activity may be required for transcriptional activation or repression of specific target promoters (By similarity). These may include the SERPINE1, to which this protein can bind directly. Mediates repression by c-Rel through a DNA-looping mechanism. Plays a role in error-free postreplication repair (PRR) of damaged DNA and maintains genomic stability through acting as a ubiquitin ligase for 'Lys-63'-linked polyubiquitination of chromatin-bound PCNA (By similarity). Transcriptional regulator that mediates the ability of prolactin to augment progesterone-dependent transcription of the SCGB1A1/uteroglobin gene through a bipartite progesterone receptor half-site/overlapping Y-box combination (-38/-26) where progesterone activation is attenuated by nuclear factor Y binding. Regulation also involves two GC-rich sequences in the proximal promoter (positions -162/+90) and a RUSH/SMARCA3 site (positions -616/-611) in the 5'-untranslated region. S-ubiquitinyl-[E2 ubiquitin-conjugating enzyme]-L-cysteine + [acceptor protein]-L-lysine = [E2 ubiquitin-conjugating enzyme]-L-cysteine + N(6)-ubiquitinyl-[acceptor protein]-L-lysine. Protein modification; protein ubiquitination. Interacts with SP1 and SP3 independently of DNA; the interaction with these transcriptional factors may be required for basal transcription of target genes (By similarity). Interacts (via the RING-finger) with isoform RFBP of ATP11B. Progesterone-dependent isoform 1 interacts with EGR1; the interaction requires prior binding to DNA and represses c-Rel via a DNA looping mechanism. Interacts with GATA4. Interacts with PCNA; the interaction promotes polyubiquitination of PCNA through association with the UBE2B-RAD18 and UBE2V2-UBE2N ubiquitin ligase complexes. Interacts with RAD18, SHPRH, UBE2V2 and UBE2N (By similarity). Cytoplasmic and nuclear localization in the presence of prolactin. Nuclear localization is stimulated by progesterone. Isoform 1 is expressed preferentially in bladder, cervix, diaphragm, duodenum, epididymis, heart, kidney, liver, lung, ovary (granulosa cells), prostate, spleen, testis (predominantly in the Sertoli cells of the seminiferous tubules) and vagina. Isoform 2 is expressed preferentially in lactating mammary gland and uterine endometrium. Isoform RUSH 1-alpha expression is increased by progesterone and decreased by estradiol. Progesterone induction is increased in the presence of prolactin. Isoform RUSH 1-beta/RFBP expression is increased by estrogen and decreased by progesterone. Phosphorylated on serine, threonine, and tyrosine residues. Tyr-195 phosphorylation is catalyzed by JAK2 in response to prolactin treatment. It is required for DNA binding. Major isoform in progesterone-dominant endometrium. Truncated, estrogen-dependent isoform. Belongs to the SNF2/RAD54 helicase family. RAD16 subfamily.