The lectin ERGIC-53 is a cargo transport receptor for glycoproteins

C Appenzeller, H Andersson, F Kappeler… - Nature cell biology, 1999 - nature.com
C Appenzeller, H Andersson, F Kappeler, HP Hauri
Nature cell biology, 1999nature.com
Soluble secretory proteins are transported from the endoplasmic reticulum (ER) to the ER–
Golgi intermediate compartment (ERGIC) in vesicles coated with COP-II coat proteins. The
sorting of secretory cargo into these vesicles is thought to involve transmembrane cargo-
receptor proteins. Here we show that a cathepsin-Z-related glycoprotein binds to the
recycling, mannose-specific membrane lectin ERGIC-53. Binding occurs in the ER, is
carbohydrate-and calcium-ion-dependent and is affected by untrimmed glucose residues …
Abstract
Soluble secretory proteins are transported from the endoplasmic reticulum (ER) to the ER–Golgi intermediate compartment (ERGIC) in vesicles coated with COP-II coat proteins. The sorting of secretory cargo into these vesicles is thought to involve transmembrane cargo-receptor proteins. Here we show that a cathepsin-Z-related glycoprotein binds to the recycling, mannose-specific membrane lectin ERGIC-53. Binding occurs in the ER, is carbohydrate-and calcium-ion-dependent and is affected by untrimmed glucose residues. Binding does not, however, require oligomerization of ERGIC-53, although oligomerization is required for exit of ERGIC-53 from the ER. Dissociation of ERGIC-53 occurs in the ERGIC and is delayed if ERGIC-53 is mislocalized to the ER. These results strongly indicate that ERGIC-53 may function as a receptor facilitating ER-to-ERGIC transport of soluble glycoprotein cargo.
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