LECTINS AS CHAPERONES IN GLYCOPROTEIN FOLDING

N-glycosylation allows newly synthesized glycoproteins to interact wit h a lectin-based chaperone system in the endoplasmic reticulum. Bindin g to the lectins calnexin and calreticulin is mediated by monoglucosyl ated oligosaccharides that are produced transiently by the deglucosyla tion and reglucosylation of substrate glycoproteins during their matur ation process. In mammalian cells, calnexin, calreticulin and associat ed factors promote the correct folding and oligomerization of many gly coproteins, providing unique quality control and chaperone functions s pecific for glycoproteins in the endoplasmic reticulum.