The network of protein-protein interactions among the BCL-2 protein family plays a critical role in regulating cellular commitment to mitochondrial apoptosis. Anti-apoptotic BCL-2 proteins are considered promising targets for drug discovery and exciting clinical progress has stimulated intense investigations in the broader family. Here, we discuss recent developments in small molecules targeting anti-apoptotic proteins and alternative approaches to targeting BCL-2 family interactions. These studies advance our understanding of the role of BCL-2 family proteins in physiology and disease, providing unique tools for dissecting these functions. The BCL-2 family of proteins is a prime example of targeting protein-protein interactions and further chemical biology approaches will increase opportunities for novel targeted therapies in cancer, autoimmune and aging-associated diseases.

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The BCL-2 family protein BAX has essential activity in mitochondrial regulation of cell death. While BAX activity ensures tissue homeostasis, when dysregulated it contributes to aberrant cell death in several diseases. During cellular stress BAX is transformed from an inactive cytosolic conformation to a toxic mitochondrial oligomer. Although the BAX transformation process is not well understood, drugs that interfere with this process are useful research tools and potential therapeutics. Here, we show that Eltrombopag,  an FDA-approved drug,  is a direct inhibitor of BAX. Eltrombopag binds the BAX trigger site distinctly from BAX activators, preventing them from triggering BAX conformational transformation and simultaneously promoting stabilization of the inactive BAX structure. Accordingly, Eltrombopag is capable of inhibiting BAX-mediated apoptosis induced by cytotoxic stimuli. Our data demonstrate structure-function insights into a mechanism of BAX inhibition and reveal a mechanism for Eltrombopag that may expand its use in diseases of uncontrolled cell death.

A method for the [2+2] cycloaddition of arylketenes and alkenes is presented. The process involves the in situ generation of a ketene in the presence of a Lewis acid. The utility of products is demonstrated towards the synthesis of a common scaffold found in several natural product families.