B-cell lymphoma 3 transcription coactivator (BCL3)

B-cell lymphoma 3 transcription coactivator (BCL3) is an atypical member of the IκB family that functions primarily as a nuclear transcriptional coactivator for NF-kappa-B p50/p52 homodimers. It was first identified due to its involvement in chromosomal translocations associated with some leukemias. The protein contains seven ankyrin repeats similar to those found in other IκB proteins. Unlike classical IκBs that inhibit NF-kappa-B by sequestering it in the cytoplasm, BCL3 acts mainly within the nucleus to modulate gene expression. Functionally, BCL3 regulates diverse cellular processes including cell proliferation, survival/apoptosis balance, DNA damage response, and immune/inflammatory signaling. Its dysregulation has been implicated in various diseases such as chronic lymphocytic leukemia, solid tumors like breast and colorectal cancers—where it promotes metastasis and poor prognosis—and inflammatory/autoimmune conditions. Although no approved drugs currently target BCL3 directly, its central role in oncogenic signaling pathways makes it an emerging therapeutic candidate for drug development aimed at modulating aberrant NF-kappa-B activity or tumor progression.

Other names

BCL4D19S37Bcl-3

Modulation of NF-kappa-B activity via interaction with p50/p52 homodimers as a nuclear transcriptional coactivator or cytoplasmic inhibitor