polypeptide N-acetylgalactosaminyltransferase 14 (protein-UDP acetylgalactosaminyltransferase 14, UDP-GalNAc:polypeptide N-acetylgalactosaminyltransferase 14, polypeptide GalNAc transferase 14, GalNAc-T14, pp-GaNTase 14, GALNT14)

Function

• catalyzes initial reaction in O-linked oligosaccharide biosynthesis, transfer of an N-acetyl-D-galactosamine to Ser or Thr on the nascent glycoprotein
• activity toward mucin-derived peptide substrates including Muc2, Muc5AC, Muc7, & Muc13
• role in O-glycosylation in kidney

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) with role in Mn+2 coordination & substrate binding
  • C-terminal domain (domain B, Gal/GalNAc-T motif) with role in catalytic reaction & UDP-Gal binding
• ricin B-type lectin domain binds to GalNAc with role in glycopeptide specificity
• belongs to the glycosyltransferase 2 family, GalNAc-T subfamily

Compartment

Golgi membrane

Alternative splicing

named isoforms=3 Expresison:

• highly expressed in fetal & adult kidney
• widely expressed at low level

More general terms

• polypeptide N-acetylgalactosaminyltransferase

Database

• OMIM: https://mirror.omim.org/entry/608225
• UniProt: http://www.uniprot.org/uniprot/Q96FL9.html