Mucin-type O-glycosylation is critical for vascular integrity

Vascular endothelial cells, in addition to many other mammalian cell types, express proteins that are highly modified with mucin-type O-glycosylation, a specific type of glycosylation that begins with the addition of an N-acetylgalactosamine moiety to serine or threonine residues within the peptide backbone. Recently, it has become evident that O-glycosylation governs the separation of blood and lymphatic vessels throughout life and plays a critical role in maintaining vascular integrity in specific tissues such as the brain and lymph node. This mini-review seeks to highlight some of these recent advances regarding in vivo functions of mucintype O-glycans.