Binding of calnexin/calreticulin to the unfolded protein

Stable Identifier
Reaction [binding]
Homo sapiens
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Calnexin (membrane protein) and calreticulin (soluble in ER) are two lectins (proteins that can bind a glycan) which recognize the mono-glucosylated form of the N-glycan and mediate the folding of the glycoproteins to which they are attached to (Ou WJ et al, 1993; Nauseef Wm et al, 1995). Calmegin is another chaperone with the same role expressed only in testis (van Lith M et al, 2007). These lectins act as chaperons, providing a protected environment where the unfolded glycoprotein can fold without forming interactions with other proteins or components in the ER. The unfolded protein can loop between these two steps multiple time, therefore this process is called the 'calnexin/calreticulin cycle'. If the protein achieves correct folding, it is modified by Mannosidase I and then moved to the cis-Golgi where the glycan is further processed.
Literature References
PubMed ID Title Journal Year
17507649 A developmentally regulated chaperone complex for the endoplasmic reticulum of male haploid germ cells

Karala, AR, Gatehouse, JA, van Lith, M, Ruddock, LW, Saunders, PT, Bown, D, Benham, AM

Mol Biol Cell 2007
8102790 Association of folding intermediates of glycoproteins with calnexin during protein maturation

Cameron, PH, Thomas, DY, Bergeron, JJ, Ou, WJ

Nature 1993
7876246 Calreticulin functions as a molecular chaperone in the biosynthesis of myeloperoxidase

Clark, RA, McCormick, SJ, Nauseef, WM

J Biol Chem 1995
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