Bromodomain-containing protein 3 (BRD3), bromodomain 1 (BD1) (BRD3 BD1)

Bromodomain-containing protein 3, bromodomain 1 (BRD3 BD1) is a critical epigenetic reader domain within the Bromodomain and Extra-Terminal (BET) family of proteins (UniProt, NIH). It functions by recognizing and binding to acetylated lysine residues on histone tails (specifically H3 and H4) and non-histone proteins, such as the hematopoietic transcription factor GATA1, to facilitate the recruitment of transcriptional regulatory complexes to chromatin (PNAS, ACS). This interaction is essential for the regulation of gene expression, particularly for genes involved in cell cycle progression and hematopoietic differentiation (Wikipedia, NIH). In clinical contexts, BRD3 is most notably associated with NUT midline carcinoma, where chromosomal translocations result in the oncogenic BRD3-NUT fusion protein (Atlas of Genetics and Cytogenetics in Oncology and Haematology, OncoKB). Pharmacological targeting of BRD3 BD1 with small-molecule inhibitors, such as the pan-BET inhibitor JQ1 or the BD1-selective inhibitor GSK778, disrupts its binding to chromatin, leading to the downregulation of key oncogenes like MYC (UniProt, NIH). While these inhibitors show significant therapeutic potential in oncology and inflammatory diseases, their clinical use is often limited by safety concerns such as dose-dependent thrombocytopenia and gastrointestinal distress (NIH).

Other names

RING3LORFXRING3-like proteinBromodomain-containing protein 3 BD1BRD3 bromodomain 1

Competitive inhibition of acetyl-lysine binding to the bromodomain hydrophobic pocket, leading to the displacement of the BET protein from chromatin and subsequent suppression of oncogenic transcriptional programs (NIH, UniProt).