gangliosideja

Gangliosides, sometimes referred to as gangliosideja in some languages, are a family of glycosphingolipids that contain one or more sialic acid residues. They reside predominantly in the outer leaflet of the plasma membrane and are especially abundant in the nervous system, where they participate in cell–cell recognition and signal transduction. A typical ganglioside consists of a ceramide lipid tail linked to an oligosaccharide chain that bears sialic acids; the ceramide anchors the molecule in the membrane.

Based on the number of sialic acid residues, gangliosides are classified into monosialo-, disialo-, trisialo-, and tetrasialo- species, commonly referred to by the GM, GD, GT, and GQ prefixes. Examples include GM1, GM2, GM3, GD1a, GD1b, GD2, GT1b, and GQ1b, each with distinct tissue distribution and functions. The GM1 ganglioside, for instance, binds the B subunit of cholera toxin.

Biosynthesis occurs in the Golgi apparatus with the sequential transfer of sugar residues to a ceramide base, forming mature gangliosides that are trafficked to the plasma membrane. Degradation takes place in lysosomes by specific hydrolases; defects cause lysosomal storage diseases known as gangliosidoses (for example GM1 gangliosidosis, GM2 gangliosidoses including Tay-Sachs and Sandhoff disease, and sialidosis).

Functions include modulation of receptor activity, synaptic transmission, neuronal development, and immune interactions; gangliosides participate in lipid rafts and can serve as binding targets for certain toxins and pathogens. Altered ganglioside metabolism is linked to neurodegenerative conditions, and diagnostic and therapeutic approaches target these pathways in some disorders.