Cloning and characterization of a novel UDP-GalNAc:polypeptide N-acetylgalactosaminyltransferase, pp-GalNAc-T14

A novel member of the human UDP- N-acetyl- d-galactosamine:polypeptide N-acetylgalactosaminyltransferase (pp-GalNAc-T) gene family was cloned and designated pp-GalNAc-T14. This type II membrane protein contains all motifs that are conserved in the pp-GalNAc-T family proteins and forms a subfamily with pp-GalNAc-T2 on the phylogenetic tree. Quantitative real time PCR analysis revealed significantly high expression of the pp-GalNAc-T14 transcript in kidney, although the transcripts were ubiquitously expressed in all tissues examined. Furthermore, the recombinant pp-GalNAc-T14 transferred GalNAc to a panel of mucin-derived peptide substrates such as Muc2, Muc5AC, Muc7, and Muc13 (-58). Our results provide evidence that pp-GalNAc-T14 is a new member of the pp-GalNAc-T family and suggest that pp-GalNAc-T14 may be involved in the O-glycosylation in kidney.