About the structure and biological function of GM3
Structure. GM3 ganglioside lipids belong to the group of gangliosides within the sphingolipids. Their structure consists of a ceramide backbone linked to an oligosaccharide unit made of three sugar molecules. One of them is a sialic acid. The ceramide backbone 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. GM3 lipids are the simplest gangliosides chemically and serve as precursors of more complex gangliosides but also fulfill a structural role themselves. In the cell membrane, they associate with each other and other lipids into lipid rafts and caveolae. The concentration of GM3 in caveolae affects the activity of receptors involved in the regulation of glucose uptake. They also are critical for cochlear hair cells and essential for hearing. Further, modified GM3 lipids are found in many cancers, including melanomas and stage II breast cancers.
