Membrane-bound and soluble molecules that are destined for intracellular organelles or the ... peptide fragments formed in the cytosol and imported into the ER through the peptide transporter ...

The endoplasmic reticulum (ER)-localized transmembrane proteins IRE1, PERK and ATF6 detect the load of unfolded protein in the lumen of the organelle ... to the cytosol for proteasomal degradation ...