The bromodomain and PHD finger-containing (BRPF) proteins are scaffolding components of chromatin-binding MOZ/MORF histone acetyltransferase complexes, which have activity as transcriptional regulators. BRPF1, aka BR140 or Peregrin, is important for maintaining Hox gene expression and the development of multiple tissues, axial skeleton, and the hematopoietic system. PFI-4 is a chemical probe that specifically binds to the bromodomain of BRPF1 (Kd = 13 nM), inhibiting binding to tri-acetylated histone 4 (residues 1-21). It has much lower affinity for bromodomain 1 of BRD4 (Kd = >50 μM) and is selective for BRPF1 over BRPF2 and BRPF3. PFI-4 is potent in cells, with an IC50 value of 250 nM. See the Structural Genomics Consortium (SGC) website for more information.
