GM2A

This gene encodes a small glycolipid transport protein which acts as a substrate specific co-factor for the lysosomal enzyme beta-hexosaminidase A. Beta-hexosaminidase A, together with GM2 ganglioside activator, catalyzes the degradation of the ganglioside GM2, and other molecules containing terminal N-acetyl hexosamines. Mutations in this gene result in GM2-gangliosidosis type AB or the AB variant of Tay-Sachs disease. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Nov 2009]

Full Name

GM2 Ganglioside Activator

Function

The large binding pocket can accommodate several single chain phospholipids and fatty acids, GM2A also exhibits some calcium-independent phospholipase activity (By similarity).

Binds gangliosides and stimulates ganglioside GM2 degradation. It stimulates only the breakdown of ganglioside GM2 and glycolipid GA2 by beta-hexosaminidase A. It extracts single GM2 molecules from membranes and presents them in soluble form to beta-hexosaminidase A for cleavage of N-acetyl-D-galactosamine and conversion to GM3 (By similarity).

Has cholesterol transfer activity (PubMed:17552909).

Biological Process

Ganglioside catabolic process Source: GO_Central
Glycosphingolipid metabolic process Source: Reactome
Learning or memory Source: Ensembl
Lipid storage Source: Ensembl
Lipid transport Source: GO_Central
Neuromuscular process controlling balance Source: Ensembl
Oligosaccharide catabolic process Source: Ensembl
Positive regulation of hydrolase activity Source: Ensembl

Cellular Location

Lysosome

Involvement in disease

GM2-gangliosidosis AB (GM2GAB):
An autosomal recessive lysosomal storage disease marked by the accumulation of GM2 gangliosides in the neuronal cells. It is characterized by GM2 gangliosides accumulation in the presence of both normal hexosaminidase A and B.

PTM

The serines in positions 32 and 33 are absent in 80% of the sequenced protein.