title: ERADication of EDEM1 occurs by selective autophagy and requires deglycosylation by cytoplasmic peptide N-glycanase.
abstract: ER degradation-enhancing α-mannosidase-like 1 protein (EDEM1) is involved in the routing of misfolded glycoproteins for degradation in the cytoplasm. Previously, we reported that EDEM1 leaves the endoplasmic reticulum via non-COPII vesicles (Zuber et al. in Proc Natl Acad Sci USA 104:4407-4412, 2007) and becomes degraded by basal autophagy (Le Fourn et al. in Cell Mol Life Sci 66:1434-1445, 2009). However, it is unknown which type of autophagy is involved. Likewise, how EDEM1 is targeted to autophagosomes remains elusive. We now show that EDEM1 is degraded by selective autophagy. It colocalizes with the selective autophagy cargo receptors p62/SQSTM1, neighbor of BRCA1 gene 1 (NBR1) and autophagy-linked FYVE (Alfy) protein, and becomes engulfed by autophagic isolation membranes. The interaction with p62/SQSTM1 and NBR1 is required for routing of EDEM1 to autophagosomes since it can be blocked by short inhibitory RNA knockdown of the cargo receptors. Furthermore, p62/SQSTM1 interacts only with deglycosylated EDEM1 that is also ubiquitinated. The deglycosylation of EDEM1 occurs by the cytosolic peptide N-glycanase and is a prerequisite for interaction and aggregate formation with p62/SQSTM1 as demonstrated by the effect of peptide N-glycanase inhibitors on the formation of protein aggregates. Conversely, aggregation of p62/SQSTM1 and EDEM1 occurs independent of cytoplasmic histone deacetylase. These data provide novel insight into the mechanism of autophagic degradation of the ER-associated protein degradation (ERAD) component EDEM1 and disclose hitherto unknown parallels with the clearance of cytoplasmic aggregates of misfolded proteins by selective autophagy.
authors.affiliation: WCU Program, Department of Integrated OMICS for Biomedical Science, Yonsei University Graduate School, Seoul, 120-749, Korea.
authors.forename: Sujin
authors.initials: S
authors.lastname: Park
authors.forename: Insook
authors.initials: I
authors.lastname: Jang
authors.forename: Christian
authors.initials: C
authors.lastname: Zuber
authors.forename: Yangsin
authors.initials: Y
authors.lastname: Lee
authors.forename: Jin Won
authors.initials: JW
authors.lastname: Cho
authors.forename: Ichiro
authors.initials: I
authors.lastname: Matsuo
authors.forename: Yukishige
authors.initials: Y
authors.lastname: Ito
authors.forename: Jürgen
authors.initials: J
authors.lastname: Roth
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000378:metabolism; D001343:Autophagy / Q000502:physiology*; D000071183:Autophagy-Related Proteins; D045744:Cell Line, Tumor; D004721:Endoplasmic Reticulum / Q000378:metabolism; D006031:Glycosylation; D056945:Hep G2 Cells; D056572:Histone Deacetylase Inhibitors; D006655:Histone Deacetylases / Q000378:metabolism; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins / Q000378:metabolism*; D018613:Microscopy, Confocal; D008856:Microscopy, Fluorescence; D016253:Microscopy, Immunoelectron; D043524:Peptide-N4-(N-acetyl-beta-glucosaminyl) Asparagine Amidase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D010588:Phagosomes / Q000378:metabolism; D017510:Protein Folding; D017346:Protein Serine-Threonine Kinases / Q000235:genetics; D021381:Protein Transport; D011506:Proteins / Q000378:metabolism; D059748:Proteolysis; D034622:RNA Interference; D034741:RNA, Small Interfering; D000071456:Sequestosome-1 Protein; D014157:Transcription Factors / Q000378:metabolism
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D000071183:Autophagy-Related Proteins; C486654:EDEM1 protein, human; D056572:Histone Deacetylase Inhibitors; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; C549756:NBR1 protein, human; D011506:Proteins; D034741:RNA, Small Interfering; C099718:SQSTM1 protein, human; D000071456:Sequestosome-1 Protein; D014157:Transcription Factors; C499825:WDFY3 protein, human; D017346:Protein Serine-Threonine Kinases; D043524:Peptide-N4-(N-acetyl-beta-glucosaminyl) Asparagine Amidase; D006655:Histone Deacetylases