polypeptide N-acetylgalactosaminyltransferase 8 (protein-UDP acetylgalactosaminyltransferase 8, UDP-GalNAc:polypeptide N-acetylgalactosaminyltransferase 8, polypeptide GalNAc transferase 8, GalNAc-T8, pp-GaNTase 8, GALNT8)

Function

• catalyzes initial reaction in O-linked oligosaccharide biosynthesis, transfer of an N-acetyl-D-galactosamine residue to Ser or Thr on protein

Structure

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

Cofactor: Mn+2, Ca+2

Compartment

• Golgi membrane; single-pass type 2 membrane protein

Expression

• widely expressed
• expressed in heart, skeletal muscle, kidney, liver, small intestine, placenta > colon, thymus, spleen, lung, leukocytes

More general terms

• polypeptide N-acetylgalactosaminyltransferase

Database

• OMIM: https://mirror.omim.org/entry/606250
• UniProt: http://www.uniprot.org/uniprot/Q9NY28.html