Walensky, LorenMcHenry, Matthew William2023-06-0220232023-06-012023-05McHenry, Matthew William. 2023. Covalent Inhibition of Pro-Apoptotic BAX. Doctoral dissertation, Harvard University Graduate School of Arts and Sciences.30491315https://nrs.harvard.edu/URN-3:HUL.INSTREPOS:37375710BCL-2-associated X protein (BAX) is a promising therapeutic target for activating or restraining apoptosis in diseases of pathologic cell survival or cell death, respectively. In response to cellular stress, BAX transforms from a quiescent cytosolic monomer into a toxic oligomer that permeabilizes the mitochondria, releasing key apoptogenic factors. The mitochondrial lipid trans-2-hexadecenal (t-2-hex) sensitizes BAX activation by covalent derivatization of cysteine 126 (C126). Here, we performed a disulfide tethering screen to discover C126-reactive molecules that modulate BAX activity. We identified covalent BAX inhibitor 1 (CBI1) as a compound that selectively derivatizes BAX at C126 and inhibits BAX activation by the physiologic ligand tBID or point mutagenesis. Biochemical and structural analyses revealed that CBI1 can inhibit BAX by a dual mechanism of action: conformational constraint and competitive blockade of lipidation. These data inform a pharmacologic strategy for blocking apoptosis in diseases of unwanted cell death by covalent targeting of BAX C126.application/pdfenApoptosisBAXBCL-2 familyCovalent InhibitionBiochemistryChemistryThesis or Dissertation2023-06-020009-0009-6734-4522