Molecular and Cellular Biochemistry

, Volume 359, Issue 1–2, pp 271–281 | Cite as

Role of cysteine amino acid residues in calnexin

  • Helen Coe
  • Jeannine D. Schneider
  • Monika Dabrowska
  • Jody Groenendyk
  • Joanna Jung
  • Marek Michalak


Calnexin is an endoplasmic reticulum protein that has a role in folding newly synthesized glycoproteins. In this study, we used site-specific mutagenesis to disrupt cysteine and histidine amino acid residues in the N- and P-domains of calnexin and determined whether these mutations impact the structure and function of calnexin. We identified that disruption of the N-domain cysteines resulted in significant loss of the chaperone activity of calnexin toward the glycosylated substrate, IgY, while disruption of the P-domain cysteines only had a small impact toward IgY. We observed that wild-type calnexin as well as the P-domain double cysteine mutant contained an intramolecular disulfide bond which is lost when the N-domain cysteines are mutated. Mutation to the N-domain histidine and N-domain cysteines resulted in increased binding of ERp57. Mutations to the P-domain cysteines further enhanced ERp57 binding to calnexin. Taken together, these observations indicated that the cysteine residues within calnexin were important for the structure and function of calnexin.


Calnexin Protein folding Endoplasmic reticulum Glycoprotein Cysteine Histidine Mutation ERp57 Structure Function 



Endoplasmic reticulum




Malate dehydrogenase



This work was supported by a grant to M.M. from the Canadian Institutes of Health Research (MOP-53050). H.C. and J.J. are supported by a studentship from the Alberta Innovates-Health Solutions.

Conflict of interest

These authors have no conflicting interest.


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Copyright information

© Springer Science+Business Media, LLC. 2011

Authors and Affiliations

  • Helen Coe
    • 1
    • 2
  • Jeannine D. Schneider
    • 2
  • Monika Dabrowska
    • 2
  • Jody Groenendyk
    • 2
  • Joanna Jung
    • 2
  • Marek Michalak
    • 1
    • 2
  1. 1.Departments of Pediatrics, School of Molecular and Systems MedicineUniversity of AlbertaEdmontonCanada
  2. 2.Department of Biochemistry, School of Molecular and Systems MedicineUniversity of AlbertaEdmontonCanada

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