polypeptide N-acetylgalactosaminyltransferase-like protein 3 (protein-UDP acetylgalactosaminyltransferase-like protein 3, UDP-GalNAc:polypeptide N-acetylgalactosaminyltransferase-like protein 3, polypeptide GalNAc transferase-like protein 3, GalNAc-T-like protein 3, pp-GaNTase-like protein 3, Williams Beuren syndrome chromosome region 17 protein, WBSCR17, GALNTL3)

Function

• glycosylation
• may catalyze the initial reaction in O-linked oligosaccharide biosynthesis, transfer of an N-acetyl-D-galactosamine residue Ser or Thr on glycoprotein

UDP-N-acetyl-D-galactosamine + polypeptide <--> UDP + N-acetyl-D-galactosaminyl-polypeptide

Cofactor: Mn+2, Ca+2

Structure

• 2 conserved domains in the glycosyltransferase region
  • N-terminal domain (domain A, GT1 motif)
    • Mn+2 coordination & substrate binding
  • C-terminal domain (domain B, Gal/GalNAc-T motif)
    • 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

Compartment

Golgi membrane

Expression

• expressed in brain, heart
• weakly expressed in kidney, liver, lung, spleen

More general terms

• glycosyltransferase
• glycoprotein

Database

• UniProt: http://www.uniprot.org/uniprot/Q6IS24.html