Dissection of the BCL-2 family signaling network with stabilized α-helices of BCL-2 domains

The BCL-2 family of apoptotic proteins regulates the critical balance between cellular life and death and, thus, has become the focus of intensive basic science inquiry and a fundamental target for therapeutic development in oncology and other diseases. Classified based on the presence of conserved alpha-helical motifs and pro- and anti-apoptotic functionalities, BCL-2 proteins participate in a complex interaction network that determines cellular fate. The identification of BCL-2 homology domain 3 (BH3) as a critical death helix that engages and regulates BCL-2 family proteins has inspired the development of molecular tools to decode and drug the interaction network. Stabilized Alpha-Helices of BCL-2 domains (SAH Bs) are structurally reinforced, protease-resistant, and cell-permeable compounds that retain the specificity of native BH3 death ligands and, therefore, serve as ideal reagents to dissect BCL-2 family interactions in vitro and in vivo. Here, we describe the in vitro and cell-based methods that exploit SAHB compounds to determine the functional consequences of BH3 interactions in regulating apoptosis.