title: Substrate recognition in ER-associated degradation mediated by Eps1, a member of the protein disulfide isomerase family.
abstract: Pma1-D378N is a misfolded plasma membrane protein in yeast that is prevented from delivery to the cell surface and targeted instead for ER-associated degradation (ERAD). Degradation of Pma1-D378N is dependent on the ubiquitin ligase Doa10 and the ubiquitin chaperone Cdc48. Recognition of Pma1-D378N by the ERAD pathway is dependent on Eps1, a transmembrane member of the protein disulfide isomerase (PDI) oxidoreductase family. Eps1 has two thioredoxin-like domains containing a CPHC and a CDKC active site. Although Eps1 interaction with wild-type Pma1 was not detected, Eps1 co-immunoprecipitates with Pma1-D378N. Eps1 interaction with Pma1-D378N requires the CPHC motif, although both thioredoxin-like domains appear to cooperate in substrate recognition. In the absence of the native transmembrane domain and cytoplasmic tail of Eps1, degradation of Pma1-D378N is slowed, suggesting that Eps1 facilitates presentation of substrate to membrane-bound components of the degradation machinery. Genetic interactions with other mutants of the ERAD machinery and induction of the unfolded protein response in eps1Delta cells support a general role for Eps1 as a recognition component of the ERAD pathway.
authors.affiliation: Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA.
authors.forename: Qiongqing
authors.initials: Q
authors.lastname: Wang
authors.forename: Amy
authors.initials: A
authors.lastname: Chang
mesh_terms: D001483:Base Sequence; D015152:Blotting, Northern; D015153:Blotting, Western; D017931:DNA Primers; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D006868:Hydrolysis; D008565:Membrane Proteins / Q000737:chemistry / Q000502:physiology*; D018832:Molecular Chaperones / Q000737:chemistry / Q000502:physiology*; D019704:Protein Disulfide-Isomerases / Q000737:chemistry / Q000502:physiology*; D029701:Saccharomyces cerevisiae Proteins; D013379:Substrate Specificity
chemical_list: D017931:DNA Primers; C402288:Eps1 protein, S cerevisiae; D008565:Membrane Proteins; D018832:Molecular Chaperones; D029701:Saccharomyces cerevisiae Proteins; D019704:Protein Disulfide-Isomerases