Globoside alpha-1,3-N-acetylgalactosaminyltransferase 1 (GBGT1)

Globoside alpha-1,3-N-acetylgalactosaminyltransferase 1 (GBGT1) is an enzyme involved in the biosynthesis of Forssman glycolipid, a member of the globoseries glycolipid family[1][4][5]. It catalyzes the transfer of N-acetylgalactosamine (GalNAc) from UDP-GalNAc to the terminal GalNAc residue of globoside by an alpha-1,3 glycosidic linkage, producing the Forssman glycolipid antigen[2][5]. This glycolipid forms specific cell-surface structures that can act as pathogen attachment sites and play a role in host-microbe interactions; its expression level may influence disease susceptibility[1][2][3]. While GBGT1 is homologous to ABO blood group transferases, most humans lack a functional enzyme due to common inactivating mutations, resulting in negative Forssman antigen status (FORS blood group), with only rare individuals expressing the FORS1 antigen[2][3]. The enzyme is classified as a glycosyltransferase of the GT6 family and is encoded on chromosome 9q34[3][5]. GBGT1 has possible roles in cancer biology because Forssman antigen is occasionally observed in tumor tissues[3].

Other names

Forssman glycolipid synthetaseForssman glycolipid synthase-like proteinForssman synthetaseForssman glycolipid synthetase (FS)Forssman blood group proteinFSUNQ2513/PRO6002A3GALNTMGC44848UDP-GalNAc

Drugs would act by inhibiting or modifying glycosyltransferase activity, but no approved drugs are known to target GBGT1[1][2][4].