InterPro: IPR011143 Ganglioside GM2 synthase

Ganglioside GM2 synthase (N-acetylgalactosaminyltransferase, GalNAcT) is one of the key enzymes in gangliosides biosynthesis, which involves a series of ER- or Golgi-based glycosyltransferases. GalNAcT is a type II integral membrane protein of the Golgi apparatus that catalyses the synthesis of the glycosphingolipids GM2, GD2, and GA2. GalNAcT and galactosyltransferase II form a Golgi-localised enzyme complex that is stabilised by non-covalent association. This enzyme association has been suggested to facilitate the biosynthesis sequence from GM3/GD3 to GM1/GD1b via GM2/GD2 as intermediates [1]. Complex gangliosides are required for the maintenance of axons and myelin [2].

Beta-1,4 N-acetylgalactosaminyltransferase (CT-GalNAcT) shares 51% sequence identity with GalNAcT, showing the strongest conservation in the catalytic domains. CT-GalNAcT is a type II Golgi transmembrane protein characteristic of other mammalian glycosyltransferases. It functions in the synthesis of murine T-lymphocyte CT antigen [3].