Maitotoxin (MTX) is an extremely potent toxin produced by Gambierdiscus toxicus, a dinoflagellate species.Maitotoxin activates Ca2+ permeable, non-selective cation channels, leading to an increase in levels of cytosolic Ca2+ ions. It is thought that maitotoxin leads to the formation of pores on these ion channels. Ultimately, a cell death cascade is activated, resulting in membrane blebbing and eventually cell lysis. Maitotoxin is known to activate cytosolic calcium-activated proteases calpain-1 and calpain-2, contributing to necrosis. The molecule itself is a system of 32 fused rings. It resembles large fatty acid chains and it is notable because it is one of the largest and most complex non-protein, non-polysaccharide molecules produced by any organism. Maitotoxin includes 32 ether rings, 22 methyls, 28 hydroxyls, and 2 sulfuric acid esters and has an amphipathic structure.
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