Bfl-1

Bfl-1, also known as BCL2A1, is an anti-apoptotic member of the BCL-2 protein family that promotes cell survival by restraining the activation of the pro-apoptotic effectors BAX and BAK, thereby limiting mitochondrial outer membrane permeabilization and caspase-dependent apoptosis^[1][2][3]. Bfl-1 functions within the intrinsic apoptotic pathway, where anti-apoptotic BCL-2 proteins bind BH3-only proteins and suppress mitochondrial cytochrome c release, a critical step in apoptosis regulation^[2][3][4]. Mechanistically, Bfl-1 contains conserved BCL-2 homology domains and acts as a pro-survival factor that sequesters pro-apoptotic signaling components under cellular stress conditions^[3][5]. In hematopoietic and endothelial cells, Bfl-1 expression is regulated by inflammatory stimuli, linking apoptosis control to immune and inflammatory signaling pathways^[6]. In disease contexts, elevated Bfl-1 expression has been reported in multiple cancers and is associated with tumor cell survival and resistance to anticancer therapies^[1][3][4]. Compared with related anti-apoptotic isoforms such as BCL-2, BCL-xL, and MCL-1, Bfl-1 remains relatively understudied and is considered a distinct pro-survival factor with unique expression patterns and therapeutic relevance in selected malignancies^[1][5]. For experimental applications, Bfl-1 has emerged as a target for BH3-mimetic drug development; however, highly selective Bfl-1 inhibitors remain limited compared with clinically established inhibitors targeting other BCL-2 family proteins^[1][4][7].