polypeptide N-acetylgalactosaminyltransferase 11 (protein-UDP acetylgalactosaminyltransferase 11, UDP-GalNAc:polypeptide N-acetylgalactosaminyltransferase 11, polypeptide GalNAc transferase 11, GalNAc-T11, pp-GaNTase 11, GALNT11)

Function

• glycosylation
• catalyzes the initial reaction in O-linked oligosaccharide biosynthesis, transfer of an N-acetyl-D-galactosamine residue to a Ser or Thr on the protein
• same enzyme activity toward Muc1, Muc4.1, & EA2 as GALNT1
• does not appear to be involved in glycosylation of erythropoietin

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

Cofactors: Mn+2, Ca+2

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
• belongs to the glycosyltransferase 2 family, GalNAc-T subfamily.
• contains 1 ricin B-type lectin domain

Compartment

Golgi membrane

Alternative splicing

named isoforms=2

Expression

• expressed in kidney > brain, heart, skeletal muscle > other tissues
• strongly expressed in renal tubules but not expressed in renal glomeruli

More general terms

• polypeptide N-acetylgalactosaminyltransferase

Database

• UniProt: http://www.uniprot.org/uniprot/Q8NCW6.html