biostudies-literatureAli RNational Institutes of HealthNIH HHSNIGMS NIH HHSe202202397https://www.ebi.ac.uk/biostudies/studies/S-EPMC9942271biostudies-literatureUnknown28(70)Phomoxanthone A is a naturally occurring molecule and a powerful anti-cancer agent, although its mechanism of action is unknown. To facilitate the determination of its biological target(s), we used affinity-based labelling using a phomoxanthone A probe. Labelled proteins were pulled down, subjected to chemoproteomics analysis using LC-MS/MS and ATP synthase was identified as a likely target. Mitochondrial ATP synthase was validated in cultured cells lysates and in live intact cells. Our studies show sixty percent inhibition of ATP synthase by 260 μM phomoxanthone A.Chemistry (Weinheim an der Bergstrasse, Germany)Phomoxanthone A Targets ATP Synthase.PMC9942271R35GM124804R35 GM124804R35 GM118112Mitroka-Batsford SParelkar SSAli RCoburn JMScarlata SFMattson AEThompson PRYerramilli SMistretta KSfalsePhomoxanthone A Targets ATP Synthase.Phomoxanthone A is a naturally occurring molecule and a powerful anti-cancer agent, although its mechanism of action is unknown. To facilitate the determination of its biological target(s), we used affinity-based labelling using a phomoxanthone A probe. Labelled proteins were pulled down, subjected to chemoproteomics analysis using LC-MS/MS and ATP synthase was identified as a likely target. Mitochondrial ATP synthase was validated in cultured cells lysates and in live intact cells. Our studies show sixty percent inhibition of ATP synthase by 260 μM phomoxanthone A.2022-01-01T00:00:00Z2022 Dec2026-03-27T15:42:39.913Z2025-04-04T11:20:31.233ZS-EPMC99422713608297710.1002/chem.202202397