Nonactin is a naturally occurring macrotetrolide antibiotic from Streptomyces griseus. Nonactin acts as an ionophore for monovalent cations, including K+, and NH4+. Nonactin is able to uncouple the oxidative phosphorylation (OXPHOS) of mitochondria. Nonactin selectively induces apoptosis in cell lines harboring active mutant β-catenin[2]. Nonactin inhibits the surface expression of endogenous HSP60.