Swinholide A, Theonella swinhoei

Swinholide A, Theonella swinhoei is a membrane permeable marine cytotoxic macrolide that acts as a specific inhibitor of actin filaments and disrupts the actin-cytoskeleton. The symmetric macrolide, isolated from Theonella swinhoei has a binding site for two actins and is described to have anti-fungal properties. Studies indicate that Swinholide A diminishes the rate of nucleotide exchange in G-actin and when bound to actin does not interact with myosin. In the presence of Swinholide A, cells have been reported to decrease actin filaments, which results in the formation and stabilization of actin dimers.