Bromodomain and Extra-Terminal domain-containing protein bromodomain 1 (BET BD1) (BET BD1)

The Bromodomain and Extra-Terminal (BET) family proteins, comprising BRD2, BRD3, BRD4, and BRDT, function as critical epigenetic readers that recognize acetylated lysine residues on histone tails to regulate gene transcription (UniProt: O60885). Each BET protein contains two conserved tandem bromodomains, BD1 and BD2, which serve distinct functional roles in chromatin interaction. The BD1 domain is primarily responsible for the initial anchoring of BET proteins to chromatin and is particularly essential for the maintenance of super-enhancer-driven oncogenic transcription (Gilan et al., Science 2020). In many cancers, such as NUT midline carcinoma and acute myeloid leukemia, the BD1 domain facilitates the overexpression of growth-promoting genes like MYC (PubMed: 27153392). Pharmacological targeting of the BD1 domain with small-molecule inhibitors, such as GSK778 or ABBV-744, displaces these proteins from chromatin, leading to cell cycle arrest and apoptosis in sensitive cell types (Faivre et al., Nature 2020). While pan-BET inhibitors target both domains, BD1-selective inhibitors are currently being developed to potentially reduce the dose-limiting toxicities, such as thrombocytopenia, associated with broad BET inhibition (ClinicalTrials.gov). These selective agents aim to provide a wider therapeutic window by specifically disrupting the BD1-mediated recruitment to chromatin while sparing some BD2-mediated functions. Overall, the BET BD1 domain represents a high-value target in precision oncology and inflammatory disease research.

Other names

N-terminal bromodomain of BET proteinsBD1 domainBromodomain 1 of the BET familyBET bromodomain 1

Competitive inhibition of the acetyl-lysine binding pocket within the N-terminal bromodomain (BD1) of BET proteins, which prevents their association with acetylated histones and disrupts the assembly of transcriptional complexes at promoters and enhancers (Gilan et al., Science 2020; Faivre et al., Nature 2020).