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The name ganglioside was first applied by the German scientist Ernst Klenk in 1942 to lipids newly isolated from ganglion cells of the brain. [1] More than 60 gangliosides are known, which differ from each other mainly in the position and number of NANA residues .
GM2-gangliosidosis, AB variant is a rare, autosomal recessive metabolic disorder that causes progressive destruction of nerve cells in the brain and spinal cord. Mutations in the GM2A gene cause AB variant. The GM2A gene provides instructions for making a protein called the GM2 activator.
GM2A is a lipid transfer protein that stimulates the enzymatic processing of gangliosides, and also T-cell activation through lipid presentation. This protein binds molecules of ganglioside GM2, extracts them from membranes, and presents them to beta- hexosaminidase A for cleavage of N-acetyl-D-galactosamine and conversion to GM3.
The secreted toxin attaches to the surface of the host mucosa cell by binding to GM1 gangliosides. GM1 consists of a sialic acid-containing oligosaccharide covalently attached to a ceramide lipid. The A1 subunit of this toxin will gain entry to intestinal epithelial cells with the assistance of the B subunit via the GM1 ganglioside receptor.
In organic chemistry, GM2 is a type of ganglioside. G refers to ganglioside, the M is for monosialic (as in it has one sialic acid), and 2 refers to the fact that it was the second monosialic ganglioside discovered. It is associated with GM2 gangliosidoses such as Tay–Sachs disease. [1]
The HEXA gene is a protein encoding gene that codes for the lysosomal enzyme beta-hexosaminidase. This enzyme, combined with the GM2 activator protein, is responsible for the breakdown of ganglioside GM2 within the lysosome. Defects in the HEXA gene, however, prevent this degradation, leading to a buildup of toxins in brain and spinal cord cells.
Sandhoff disease is a lysosomal genetic, lipid storage disorder caused by the inherited deficiency to create functional beta-hexosaminidases A and B. [1] [2] These catabolic enzymes are needed to degrade the neuronal membrane components, ganglioside GM2, its derivative GA2, the glycolipid globoside in visceral tissues, [1] and some oligosaccharides.
This enzyme catalyses the formation of the gangliosides (i.e. sialic-acid-containing glycosphingolipids) GM2, GD2 and SM2 from GM3, GD3 and SM3, respectively. References [ edit ]