Bromodomain and extra-terminal domain (BET) protein (BET)

Bromodomain and extra-terminal domain (BET) proteins are a family of epigenetic readers that play a central role in regulating gene transcription by recognizing acetylated lysine residues on histone tails and non-histone proteins (NIH, 2021). The family consists of four members in humans: BRD2, BRD3, BRD4, and the testis-specific BRDT (Wikipedia, 2024). These proteins act as scaffolds to recruit transcriptional machinery, such as the positive transcription elongation factor b (P-TEFb) and the Mediator complex, to specific genomic loci, thereby facilitating the expression of genes involved in cell growth, survival, and inflammation (NIH, 2021; MDPI, 2023). In many cancers, BET proteins, particularly BRD4, are dysregulated and drive the overexpression of critical oncogenes like MYC, making them attractive therapeutic targets (MDPI, 2023; NIH, 2024). Small-molecule BET inhibitors work by competitively binding to the bromodomains, displacing the proteins from chromatin and suppressing oncogenic transcriptional programs (Patsnap, 2024). Beyond oncology, BET proteins are implicated in inflammatory diseases, cardiovascular conditions, and viral latency, though clinical development has faced challenges such as dose-limiting thrombocytopenia and potential off-target effects (NIH, 2020; Frontiers in Pharmacology, 2021).

Other names

BET familyBET bromodomain proteinsBromodomain-containing protein 2Bromodomain-containing protein 3Bromodomain-containing protein 4Bromodomain-containing protein, testis-specific

BET inhibitors competitively bind to the bromodomains (BD1 and BD2) of BET proteins, preventing their interaction with acetylated lysine residues on histones and transcription factors (Wikipedia, 2024). This displacement from chromatin disrupts the recruitment of transcriptional co-activators such as the positive transcription elongation factor b (P-TEFb) and the Mediator complex, leading to the downregulation of key oncogenic and pro-inflammatory genes including MYC, BCL2, and various cytokines (NIH, 2021; MDPI, 2023).