MF-094 is a potent inhibitor of ubiquitin specific protease 30 (USP30), a de-ubiquitinating enzymes (DUB) th at opposes the action of parkin-mediated ubiquitination in clearing damaged mitochondria. MF-094 is selective for USP30 with an IC50 value of 120 nM, compared to >10 μM for USPs 1, 8, and 9.