Expression and Function of the HNK-1 Carbohydrate

• Published in: Journal of biochemistry (Tokyo) Vol. 143; no. 6; pp. 719 - 724
• Main Authors: Morita, Ippei, Kizuka, Yasuhiko, Kakuda, Shinako, Oka, Shogo
• Format: Journal Article
• Language: English
• Published: England Japanese Biochemical Society 01.06.2008; Oxford University Press
• Subjects: Animals; CD57 Antigens - chemistry; CD57 Antigens - physiology; enzyme complex; Glucuronosyltransferase - chemistry; Glucuronosyltransferase - metabolism; glucuronyltransferase; HNK-1; Humans; long-term potentiation; substrate specificity; Sulfotransferases - chemistry; Sulfotransferases - metabolism; enzyme complex; glucuronyltransferase; substrate specificity; HNK-1, long-term potentiation
• ISSN: 0021-924X; 1756-2651
• DOI: 10.1093/jb/mvm221

Glycosylation is a major post-translational protein modification, especially for cell surface proteins, which play important roles in a variety of cellular functions, including recognition and adhesion. Among them, we have been interested in HNK-1 (human natural killer-1) carbohydrate, which is characteristically expressed on a series of cell adhesion molecules in the nervous system. The HNK-1 carbohydrate has a unique structural feature, i.e. a sulfated glucuronic acid is attached to the non-reducing terminal of an N-acetyllactosamine residue (HSO3-3GlcAβ1-3Galβ1-4GlcNAc-). We have cloned and characterized the biosynthetic enzymes (two glucuronyltransferases and a sulfotransferase), and also obtained evidence that the HNK-1 carbohydrate is involved in synaptic plasticity and memory formation. In this review, we describe recent findings regarding the expression mechanism and functional roles of this carbohydrate.