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

Nat Cell Biol. 1999 Oct;1(6):330-4. doi: 10.1038/14020.

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Carbohydrate Metabolism
  • Carrier Proteins / genetics
  • Carrier Proteins / metabolism*
  • Cathepsin K
  • Cathepsin Z
  • Cathepsins / metabolism*
  • Cell Line
  • Endoplasmic Reticulum / metabolism*
  • Glycoproteins / metabolism*
  • Humans
  • Lectins / genetics
  • Lectins / metabolism*
  • Mannose-Binding Lectins*
  • Membrane Proteins / genetics
  • Membrane Proteins / metabolism*
  • Mice
  • Molecular Sequence Data
  • Rabbits

Substances

  • Carrier Proteins
  • ERGIC-53 protein, mouse
  • Glycoproteins
  • LMAN1 protein, human
  • Lectins
  • Mannose-Binding Lectins
  • Membrane Proteins
  • Cathepsins
  • CTSZ protein, human
  • Cathepsin Z
  • Ctsz protein, mouse
  • CTSK protein, human
  • Cathepsin K
  • Ctsk protein, mouse