polypeptide N-acetylgalactosaminyltransferase 1; protein-UDP acetylgalactosaminyltransferase 1; UDP-GalNAc:polypeptide N-acetylgalactosaminyltransferase 1; polypeptide GalNAc transferase 1; GalNAc-T1, pp-GaNTase 1 [Contains: polypeptide N-acetylgalactosaminyltransferase 1 soluble form] (GALNT1)

Function

• glycoprotein synthesis
• catalyzes initial reaction in O-linked oligosaccharide biosynthesis, transfer of an N-acetyl-D-galactosamine residue to Ser or Thr on nascent protein
• broad spectrum of substrates for peptides including: EA2, Muc5AC, Muc1a, Muc1b
• role in O-linked glycosylation of IgA1 hinge region
• ricin B-type lectin domain binds to GalNAc & contributes to glycopeptide specificity

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

Structure

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

Cofactor: Mn+2, Ca+2

Compartment

• Golgi (preferentially trans & medial parts)
• secreted

Alternative splicing

named isoforms=2

Expression

widely expressed

More general terms

• glycosyltransferase

Database

• OMIM: https://mirror.omim.org/entry/602273
• UniProt: http://www.uniprot.org/uniprot/Q10472.html