GSK8814 is a selective and ATAD2 2B bromodomain chemical probe and inhibitor (binding constant pKd=8.1 and a pKi=8.9 in BROMOscan). GSK8814 displays 500-fold selectivity for ATAD2 over BRD4 BD1. GSK8814 binds to ATAD2 and BRD4 BD1 (pIC50s: 7.3 and 4.6).
dBRD4-BD1 is a selective BRD4 bromodomain inhibitor. dBRD4-BD1 can selectively degrade BRD4 (DC50 = 280 nM). Notably, dBRD4-BD1 upregulates BRD2 3, a result not observed with degraders using pan-BET ligands. Designing BRD4 selectivity up front enables analysis of BRD4 biology without wider BET-inhibition and simplifies designing BRD4-selective heterobifunctional molecules, such as degraders with new E3 recruiting ligands or for additional probes beyond degraders.