Journal of Biochemistry Advance Access originally published online on November 16, 2007
Journal of Biochemistry 2008 143(6):719-724; doi:10.1093/jb/mvm221
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
© 2007 The Japanese Biochemical Society
JB Minireview-New Paradigm in Glycobiology |
Expression and Function of the HNK-1 Carbohydrate
1Department of Biological Chemistry, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto 606-8501; and 2Department of Biological Chemistry, Human Health Science, Graduate School of Medicine, Kyoto University, Kyoto 606-8507, Japan
*To whom correspondence should be addressed. Tel: +81 75 751 3959, Fax: +81 75 751 3959, E-mail: shogo{at}hs.med.kyoto-u.ac.jp
Received October 25, 2007; Accepted November 8, 2007
| Abstract |
|---|
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.
Key Words: enzyme complex, glucuronyltransferase, HNK-1, long-term potentiation, substrate specificity
Abbreviations: AMPA, alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid; ASOR, asialo-orosomucoid; CA1, cornu ammonis 1; EPSP, excitatory post-synaptic potential; GlcAT, glucuronyltransferase; HNK-1, human natural killer-1; HNK-1ST, HNK-1 sulfotransferase; LTP, long-term potentiation; NCAM, neural cell adhesion molecule; PI, phosphatidylinositol; PN, perineuronal net; SGGL, sulfoglucuronyl glycolipid; SM, sphingomyelin; TRP, transient receptor potential