Direct Small Molecule Activation of Mitofusins

Mitochondrial fusion is a physiological process that is regulated by mitofusins on the outer mitochondrial membrane. Conformational plasticity between anti- and pro-tethering conformations of mitofusins permits mitochondrial tethering and subsequent fusion. Here we developed a pharmacophore-based model to rationally manipulate the conformational plasticity of mitofusin 2 and perfomed an in silico small-molecule screen. This enabled the discovery of a direct activator of mitofusins, MASM7, capable of potently promoting mitochondrial fusion. The specificity of the MASM7-mitofusin 2 interaction is highlighted by structure-activity relationships of MASM7 analogues, FRET, NMR and mitochondrial fusion studies using mitofusin mutants. Our study identified the first-in-class direct activator of mitofusins, demonstrating a new paradigm for chemical modulation of mitochondrial fusion and downstream processes.