Lectins and traffic in the secretory pathway

Evidence is accumulating that intracellular animal lectins play important r oles in quality control and glycoprotein sorting along the secretory pathwa y. Calnexin and calreticulin in conjunction with associated chaperones prom ote correct folding and oligomerization of many glycoproteins in the endopl asmic reticulum (ER), The mannose lectin ERGIC-53 operates as a cargo recep tor in transport of glycoproteins from ER to Golgi and the homologous lecti n VIP36 may operate in quality control of glycosylation in the Golgi. Exit from the Golgi of lysosomal hydrolases to endosomes requires mannose 6-phos phate receptors and exit to the apical plasma membrane may also involve tra ffic lectins. Here we discuss the features of these lectins and their role in glycoprotein traffic in the secretory pathway, (C) 2000 Federation of Eu ropean Biochemical Societies. Published by Elsevier Science B.V. All rights reserved.