Transcriptional regulator that plays a central role in Notch signaling, a signaling pathway involved in cell-cell communication that regulates a broad spectrum of cell-fate determinations (PubMed:7566092). Acts as a transcriptional repressor when it is not associated with Notch proteins. When associated with some NICD product of Notch proteins (Notch intracellular domain), it acts as a transcriptional activator that activates transcription of Notch target genes (By similarity) (PubMed:18381292). Probably represses or activates transcription via the recruitment of chromatin remodeling complexes containing histone deacetylase or histone acetylase proteins, respectively. Specifically binds to the immunoglobulin kappa-type J segment recombination signal sequence. Binds specifically to methylated DNA. Binds to the oxygen responsive element of COX4I2 and activates its transcription under hypoxia conditions (4% oxygen) (By similarity). Negatively regulates the phagocyte oxidative burst in response to bacterial infection by repressing transcription of NADPH oxidase subunits (PubMed:26194095). Interacts with RITA1, leading to nuclear export, prevent the interaction between RBPJ and NICD product and subsequent down-regulation of the Notch signaling pathway (By similarity). Interacts with activated NOTCH1, NOTCH2 and NOTCH3. Interacts with MINT/SHARP. This interaction may mediate the recruitment of large corepressor complexes containing proteins such as HDAC1, HDAC2, NCOR2, SAP30, FHL1/KYOT2 and CIR1. Interacts with EP300, MAML1 and PTF1A. Interacts with SNW1. Interacts with CHCHD2 and CXXC5. Interacts with BEND6 (via BEN domain) (By similarity). Interacts with NKAPL (PubMed:25875095). Interacts with ZMIZ1 (By similarity). Interacts with RBM15 (PubMed:17283045). Mainly nuclear, upon interaction with RITA1, translocates to the cytoplasm, down-regulating the Notch signaling pathway. Belongs to the Su(H) family. Despite some similarity with the 'phage' integrase family, it has no recombinase activity.