Description_x000D_ General description_x000D_ Calyculin A is derived from the marine sponge Discodermia calyx. It corresponds to a molecular weight of 1008 Da._x000D_ Application_x000D_ Calyculin A from Discodermia calyx has been used:_x000D_ • as an inhibitor of serine-threonine protein phosphatase 2A_x000D_ • as an inhibitor of cyclin D1 phosphatase in human breast cancer cells_x000D_ • as an inhibitor of protein phosphatase 2A (PP2A) and PP1 in mouse melanoma cell lines B16-F0 cells_x000D_ Biochem/physiol Actions_x000D_ Calyculin A from Discodermia calyx binds to the okadaic acid receptors. In smooth muscles, it activates calcium channel. Calyculin A regulates protein phosphorylation thereby regulating capacitation in sperm. It enhances phosphorylation of nuclear factor κ-light-chain-enhancer of activated B cells (NF-κB) and apoptosis._x000D_ Inhibitor of protein phosphatases types 1 and 2A; marine toxin, potent tumor promotor._x000D_ Features and Benefits_x000D_ This compound is featured on the Phosphoprotein Phosphatases (Serine/Threonine) page of the Handbook of Receptor Classification and Signal Transduction. To browse other handbook pages, click here.