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. Nonactin inhibits the surface expression of endogenous HSP60.