Why are glycoproteins modified by poly-N-acetyllactosamine glyco-conjugates?
Poly-N-acetyllactosamine structures occur in mammalian glycoproteins in both N- and O-linked glycans. They represent a backbone for additional modifications by fucosyltransferases, sialyltransferases and sulfotransferases. These glycans have been suggested to be involved in biospecific interactions with selectins and other glycan-binding proteins. Moreover, the poly-N-acetyllactosamine chains in N-glycans have been found to promote tumor progression and metastasis. Poly-N-acetyllactosamine chains are synthesized by repeated alternating additions of N-acetylglucosamine and galactose, catalyzed by beta-1,3-N-acetylglucosaminyltransferases (poly-N-acetyllactosamine synthase) and beta-1,4-galactosyltransferases. This review describes the poly-N-acetyllactosamine assembling machinery and focuses on recent advances in the molecular cloning and characterization of poly-N-acetyllactosamine synthase gene families. Recent progress in revealing the biological functions of poly-N-acetyllactosamine structures by various approaches in vitro and in vivo using different model systems has also been summarized.
Zhou
Dapeng
D
Department of Pathology, University of Chicago, 5841 S. Maryland Avenue, MC 1089 Chicago, IL 60637, USA. dzhou@midway.uchicago.edu
D000818:Animals; D005700:Galactosyltransferases / Q000378:metabolism; D006001:Glycoconjugates / Q000378:metabolism*; D006023:Glycoproteins / Q000378:metabolism*; D006801:Humans; D011134:Polysaccharides / Q000378:metabolism*; D013329:Structure-Activity Relationship; D013379:Substrate Specificity
D006001:Glycoconjugates; D006023:Glycoproteins; D011134:Polysaccharides; C037199:poly-N-acetyllactosamine; D005700:Galactosyltransferases