BAT3 guides misfolded glycoproteins out of the endoplasmic reticulum

PLoS One. 2011;6(12):e28542. doi: 10.1371/journal.pone.0028542. Epub 2011 Dec 8.

Abstract

Secretory and membrane proteins that fail to acquire their native conformation within the lumen of the Endoplasmic Reticulum (ER) are usually targeted for ubiquitin-dependent degradation by the proteasome. How partially folded polypeptides are kept from aggregation once ejected from the ER into the cytosol is not known. We show that BAT3, a cytosolic chaperone, is recruited to the site of dislocation through its interaction with Derlin2. Furthermore, we observe cytoplasmic BAT3 in a complex with a polypeptide that originates in the ER as a glycoprotein, an interaction that depends on the cytosolic disposition of both, visualized even in the absence of proteasomal inhibition. Cells depleted of BAT3 fail to degrade an established dislocation substrate. We thus implicate a cytosolic chaperone as an active participant in the dislocation of ER glycoproteins.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Endoplasmic Reticulum / metabolism*
  • Glycoproteins / metabolism*
  • HEK293 Cells
  • HeLa Cells
  • Humans
  • Membrane Proteins / metabolism
  • Molecular Chaperones / metabolism*
  • Protein Binding
  • Protein Folding*
  • Protein Transport
  • Proteolysis
  • Receptors, Antigen, T-Cell, alpha-beta / metabolism

Substances

  • BAG6 protein, human
  • DERL2 protein, human
  • Glycoproteins
  • Membrane Proteins
  • Molecular Chaperones
  • Receptors, Antigen, T-Cell, alpha-beta