The lectin domain of UDP-N-acetyl-D-galactosamine : polypeptide N-acetylgalactosaminyltransferase-T4 directs its glycopeptide specificities

• Type: Article in International Scientific Journal
• Date: 2000

Authors

Hassan, H (Author) Other; Celso Reis (Author) Other; Bennett, EP (Author) Other; Mirgorodskaya, E (Author) Other; Roepstorff, P (Author) Other; Hollingsworth, MA (Author) Other; Burchell, J (Author) Other; Taylor Papadimitriou, J (Author) Other; Clausen, H (Author) Other

Journal

Title: Journal of Biological Chemistry

Vol. 275

Pages: 38197-38205

ISSN: 0021-9258

Publisher: Elsevier

Indexing

ISI Web of Knowledge - 131 Citations

Scopus - 136 Citations

Other information

Authenticus ID: P-000-Y6X

DOI: 10.1074/jbc.m005783200

Abstract (EN): The initiation step of mucin-type O-glycosylation is controlled by a large family of homologous UDP-GalNAc: polypeptide N-acetylgalactosaminyltransferases (GalNAc-transferases), Differences in kinetic properties, substrate specificities, and expression patterns of these isoenzymes provide for differential regulation of O-glycan attachment sites and density, Recently, it has emerged that some GalNAc-transferase isoforms in, vitro selectively function with partially GalNAc O-glycosylated acceptor peptides rather than with the corresponding unglycosylated peptides, O-Glycan attachment to selected sites, most notably two sites in the MUC1 tandem repeat, is entirely dependent on the glycosylation-dependent function of GalNAc-T4. Here we present data that a putative lectin domain found in the C terminus of GalNAc-T4 functions as a GalNAc lectin and confers its glycopeptide specificity. A single amino acid substitution in the lectin domain of a secreted form of GalNAc-T4 selectively blocked GalNAc-glycopeptide activity, while the general activity to peptides exerted by this enzyme was unaffected. Furthermore, the GalNAc-glycopeptide activity of wild-type secreted GalNAc-T4 was selectively inhibited by free GalNAc, while the activity with peptides was unaffected.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 9