Polypeptide-N-Acetylgalactosaminyltransferase 8 (GALNT8)

GALNT8 encodes a member of the UDP-N-acetyl-alpha-D-galactosamine:polypeptide N-acetylgalactosaminyltransferase (GalNAc-T) family of enzymes. GalNAc-Ts initiate mucin-type O-linked glycosylation in the Golgi apparatus by catalyzing the transfer of GalNAc to serine and threonine residues on target proteins. They are characterized by an N-terminal transmembrane domain, a stem region, a lumenal catalytic domain containing a GT1 motif and Gal/GalNAc transferase motif, and a C-terminal ricin/lectin-like domain. GalNAc-Ts have different, but overlapping, substrate specificities and patterns of expression.The deduced 637-amino acid type II integral membrane protein has an N-terminal 6-residue cytoplasmic region, a single transmembrane domain, a 118-amino acid stem region, and a long luminal region with a ricin/lectin-like domain.