||Stephen B Helliwell, Shantanu Karkare, Marc Bergdoll, Alain Rahier, Juliet R Leighton-Davis, Celine Fioretto, Thomas Aust, Ireos Filipuzzi, Mathias Frederiksen, John Gounarides, Dominic Hoepfner, Andreas Hofmann, Pierre-Eloi Imbert, Rolf Jeker, Richard Knochenmuss, Philipp Krastel, Anais Margerit, Klaus Memmert, Charlotte V Miault, N Rao Movva, Alban Muller, Hans-Ulrich Naegeli, Lukas Oberer, Vivian Prindle, Ralph Riedl, Sven Schuierer, Jessica A Sexton, Jianshi Tao, Trixie Wagner, Hong Yin, Juan Zhang, Silvio Roggo, Stefan Reinker, Christian N Parker
||FR171456 is a natural product with cholesterol-lowering properties in animal models, but its molecular target is unknown, which hinders further drug development. Here we show that FR171456 specifically targets the sterol-4-alpha-carboxylate-3-dehydrogenase (Saccharomyces cerevisiae--Erg26p, Homo sapiens--NSDHL (NAD(P) dependent steroid dehydrogenase-like)), an essential enzyme in the ergosterol/cholesterol biosynthesis pathway. FR171456 significantly alters the levels of cholesterol pathway intermediates in human and yeast cells. Genome-wide yeast haploinsufficiency profiling experiments highlight the erg26/ERG26 strain, and multiple mutations in ERG26 confer resistance to FR171456 in growth and enzyme assays. Some of these ERG26 mutations likely alter Erg26 binding to FR171456, based on a model of Erg26. Finally, we show that FR171456 inhibits an artificial Hepatitis C viral replicon, and has broad antifungal activity, suggesting potential additional utility as an anti-infective. The discovery of the target and binding site of FR171456 within the target will aid further development of this compound.