1. Identification of the PDI-family member ERp90 as an interaction partner of ERFAD
- Author
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Riemer, Jan, Hansen, Henning G, Appenzeller-Herzog, C., Appenzeller-Herzog, Christian, Johansson, Linda, and Ellgaard, Lars
- Subjects
Glycobiology ,Sequence Homology ,Plasma protein binding ,Endoplasmic Reticulum ,Biochemistry ,Molecular Cell Biology ,Macromolecular Structure Analysis ,Protein disulfide-isomerase ,Protein maturation ,Cells, Cultured ,Macromolecular Complex Analysis ,Cellular Stress Responses ,0303 health sciences ,Multidisciplinary ,Membrane Glycoproteins ,Enzyme Classes ,030302 biochemistry & molecular biology ,Recombinant Proteins ,Enzymes ,Carbohydrate Sequence ,Multigene Family ,Medicine ,Membranes and Sorting ,Thioredoxin ,Oxidoreductases ,Protein Binding ,Research Article ,Immunoprecipitation ,Science ,Green Fluorescent Proteins ,Molecular Sequence Data ,Protein Disulfide-Isomerases ,Sequence alignment ,Endoplasmic-reticulum-associated protein degradation ,Biology ,Protein Chemistry ,03 medical and health sciences ,Antigens, Neoplasm ,Polysaccharides ,Humans ,Protein Interaction Domains and Motifs ,Amino Acid Sequence ,Protein Interactions ,030304 developmental biology ,Glycoproteins ,Flavoproteins ,Endoplasmic reticulum ,Proteins ,Computational Biology - Abstract
In the endoplasmic reticulum (ER), members of the protein disulfide isomerase (PDI) family perform critical functions during protein maturation. Herein, we identify the previously uncharacterized PDI-family member ERp90. In cultured human cells, we find ERp90 to be a soluble ER-luminal glycoprotein that comprises five potential thioredoxin (Trx)-like domains. Mature ERp90 contains 10 cysteine residues, of which at least some form intramolecular disulfides. While none of the Trx domains contain a canonical Cys-Xaa-Xaa-Cys active-site motif, other conserved cysteines could endow the protein with redox activity. Importantly, we show that ERp90 co-immunoprecipitates with ERFAD, a flavoprotein involved in ER-associated degradation (ERAD), through what is most likely a direct interaction. We propose that the function of ERp90 is related to substrate recruitment or delivery to the ERAD retrotranslocation machinery by ERFAD.
- Published
- 2010