Gangliosides are formed from a glycosphingolipid combined with one or more sialic acids at the oligosaccharide chain. They are anchored at the outer surface of the plasma membrane where they pack densely with cholesterol to form lipid microdomains that modulate both intra- and inter-cellular signaling events. Ganglioside GQ1b is a tetrasialoganglioside that is characterized by having two sialic residues linked to the inner galactose unit. At 5 nM, it can stimulate an ecto-type (cell-surface) protein phosphorylation system in the human neuroblastoma cell line GOTO. Ganglioside GQ1b has been reported to promote neurite outgrowth during early neuronal differentiation by activating the ERK1/2 MAP kinase pathway. It has also been shown to initiate keratinocyte differentiation through phophoinositide turnover.
