– BFL-1 inhibitor 4E14 (4E14) is a potent, selective, covalent BFL-1 inhibitor that disrupt BH3-binding activity with IC50 of 1.3 uM, targets a unique C55 residue in the BFL-1 groove.4E14 blocks BFL-1 suppression of BAX-mediated mitochondrial apoptosis.