Reconstitution of glycopeptide export in mixed detergent-solubilised and resealed microsomes depleted of lumenal components.

摘要: Export of macromolecules from the endoplasmic reticulum (ER) lumen into cytosol is a major aspect quality control systems operating within early secretory system. Glycopeptides are exported ER by an ATP- and GTP-dependent pathway, which shares many similarities to protein export Significantly, for glycopeptides, there no requirement cytosolic factors, biochemically distinguishing glycopeptide paths probably reflecting lower conformational complexity former substrate. Genetic studies in yeast, biochemical data higher eukaryotes, indicate that glycopeptides utilise Sec61 translocon. Here, we report new system allowing access lumenal components, facilitating assessment their importance retrotranslocation potentially other processes. Saponin, combination with CHAPS, but not saponin alone, facilitated removal >95% disulphide isomerase (PDI) BiP. Upon resealing, these microsomes retained competence. These suggest majority components most likely nonessential export. In addition, competence was highly sensitive addition external protease, indicating role factors cytoplasmically exposed determinants.