pH-induced conversion of the transport lectin ERGIC-53 triggers glycoprotein release

Appenzeller-Herzog, Christian and Roche, Annie-Claude and Nufer, Oliver and Hauri, Hans-Peter. (2004) pH-induced conversion of the transport lectin ERGIC-53 triggers glycoprotein release. Journal of Biological Chemistry, 279 (13). pp. 12943-12950.

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Official URL: http://edoc.unibas.ch/dok/A5257752

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The recycling mannose lectin ERGIC-53 operates as a transport receptor by mediating efficient endoplasmic reticulum (ER) export of some secretory glycoproteins. Binding of cargo to ERGIC-53 in the ER requires Ca2+. Cargo release occurs in the ERGIC, but the molecular mechanism is unknown. Here we report efficient binding of purified ERGIC-53 to immobilized mannose at pH 7.4, the pH of the ER, but not at slightly lower pH. pH sensitivity of the lectin was more prominent when Ca2+ concentrations were low. A conserved histidine in the center of the carbohydrate recognition domain was required for lectin activity suggesting it may serve as a molecular pH/Ca2+ sensor. Acidification of cells inhibited the association of ERGIC-53 with the known cargo cathepsin Z-related protein and dissociation of this glycoprotein in the ERGIC was impaired by organelle neutralization that did not impair the transport of a control protein. The results elucidate the molecular mechanism underlying reversible lectin/cargo interaction and establish the ERGIC as the earliest low pH site of the secretory pathway.
Faculties and Departments:05 Faculty of Science > Departement Biozentrum > Former Organization Units Biozentrum > Pharmacology/Neurobiology (Hauri)
05 Faculty of Science > Departement Pharmazeutische Wissenschaften > Pharmazie > Molecular and Systems Toxicology (Odermatt)
UniBasel Contributors:Hauri, Hans-Peter and Appenzeller-Herzog, Christian
Item Type:Article, refereed
Article Subtype:Research Article
Publisher:American Society for Biochemistry and Molecular Biology
Note:Publication type according to Uni Basel Research Database: Journal article
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Last Modified:21 Sep 2020 13:04
Deposited On:22 Mar 2012 13:18

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