This gene encodes a protein that is involved in the activation of the ubiquitous transcription factor NF-kappaB. This protein is associated with the the histone deacetylase HDAC3 and with the Notch corepressor complex, and it thereby acts as a transcriptional repressor of Notch target genes. It is also required for alphabeta T cell development. A related pseudogene has been identified on chromosome X, while a related and intronless retrocopy, which has an intact CDS and may be functional, is located on chromosome 6.