title: Location, location, location: new insights into O-GalNAc protein glycosylation.
abstract: O-GalNAc glycosylation of proteins confers essential structural, protective and signaling roles in eumetazoans. Addition of O-glycans onto proteins is an extremely complex process that regulates both sites of attachment and the types of oligosaccharides added. Twenty distinct polypeptide GalNAc-transferases (GalNAc-Ts) initiate O-glycosylation and fine-tuning their expression provides a mechanism for regulating this action. Recently, a new mode of regulation has emerged where activation of Src kinase selectively redistributes Golgi-localized GalNAc-Ts to the ER. This relocalization results in a strong increase in the density of O-glycan decoration. In this review, we discuss how different mechanisms can regulate the number and the types of O-glycans decorating proteins. In addition, we speculate how Src-dependent relocation of GalNAc-Ts could play an important role in cancerous cellular transformation.
authors.affiliation: Institute of Molecular and Cell Biology (IMCB), Proteos, 61 Biopolis Drive, Singapore, 138673.
authors.forename: David J
authors.initials: DJ
authors.lastname: Gill
authors.forename: Henrik
authors.initials: H
authors.lastname: Clausen
authors.forename: Frederic
authors.initials: F
authors.lastname: Bard
mesh_terms: D000818:Animals; D006023:Glycoproteins / Q000737:chemistry / Q000378:metabolism*; D006031:Glycosylation; D006801:Humans; D017350:N-Acetylgalactosaminyltransferases / Q000378:metabolism; D011134:Polysaccharides / Q000378:metabolism; D021381:Protein Transport; D013379:Substrate Specificity; D000097763:Polypeptide N-acetylgalactosaminyltransferase
chemical_list: D006023:Glycoproteins; D017350:N-Acetylgalactosaminyltransferases; D011134:Polysaccharides; D000097763:Polypeptide N-acetylgalactosaminyltransferase