Structure. Trisialogangliosides (GT) belong to the group of gangliosides within the sphingolipids. Their structure consists of a ceramide backbone linked to an oligosaccharide. Three of the sugar molecules are sialic acids. The total number of sugar molecules is part of the name of GT subclasses: GT1 contains seven sugars, GT2 six, and GT3 five. The ceramide backbone of trisialogangliosides contains two hydrocarbon chains: a long-chain base which is linked to a fatty acid via an amide bond. The fatty acid and the long-chain base can be of variable length, hydroxylated, and contain double bonds.
Function. The biological role of trisialogangliosides is mostly associated with the neural system. Within the cell membrane of the axons of neurons, GT1 gangliosides bind to the myelin-associated glycoprotein. This interaction maintains and regulates axon-myelin stability. Little is known about the function of GT2 gangliosides and GT3 gangliosides. But modified GT2 gangliosides have been associated with tumors, and GT3 gangliosides are elevated in the retina where they are believed to play a specific role in the structure and function of the tissue.
