N-acetylgalactosaminyltransferase 7 (protein-UDP acetylgalactosaminyltransferase 7, UDP-GalNAc:polypeptide N-acetylgalactosaminyltransferase 7, polypeptide GalNAc transferase 7, GalNAc-T7, pp-GaNTase 7, GALNT7)

Function

• glycopeptide transferase involved in O-linked oligosaccharide biosynthesis
• catalyzes transfer of an N-acetyl-D-galactosamine residue to an already glycosylated peptide
• does NOT transfer GalNAc onto Ser or Thr residue
  • requires prior addition of a GalNAc on a peptide before adding additional GalNAc moieties

Cofactor: Mn+2, Ca+2

Structure

• 2 conserved domains in the glycosyltransferase region
  • N-terminal domain (domain A, GT1 motif), involved in Mn+2 coordination & substrate binding
  • C-terminal domain (domain B, Gal/GalNAc-T motif), involved in catalytic reaction & UDP-Gal binding
• ricin B-type lectin domain binds to GalNAc, contributes to glycopeptide specificity
• belongs to the glycosyltransferase 2 family, GalNAc-T subfamily
• contains 1 ricin B-type lectin domain

Compartment

Golgi membrane

Expression

• widely expressed
• expressed in uterus, retina, kidney, small intestine, omentum, stomach, CNS

More general terms

• glycosyltransferase

Database

• OMIM: https://mirror.omim.org/entry/605005
• UniProt: http://www.uniprot.org/uniprot/Q86SF2.html