title: ERManI (Endoplasmic Reticulum Class I α-Mannosidase) Is Required for HIV-1 Envelope Glycoprotein Degradation via Endoplasmic Reticulum-associated Protein Degradation Pathway.
abstract: Previously, we reported that the mitochondrial translocator protein (TSPO) induces HIV-1 envelope (Env) degradation via the endoplasmic reticulum (ER)-associated protein degradation (ERAD) pathway, but the mechanism was not clear. Here we investigated how the four ER-associated glycoside hydrolase family 47 (GH47) α-mannosidases, ERManI, and ER-degradation enhancing α-mannosidase-like (EDEM) proteins 1, 2, and 3, are involved in the Env degradation process. Ectopic expression of these four α-mannosidases uncovers that only ERManI inhibits HIV-1 Env expression in a dose-dependent manner. In addition, genetic knock-out of the ERManI gene MAN1B1 using CRISPR/Cas9 technology disrupts the TSPO-mediated Env degradation. Biochemical studies show that HIV-1 Env interacts with ERManI, and between the ERManI cytoplasmic, transmembrane, lumenal stem, and lumenal catalytic domains, the catalytic domain plays a critical role in the Env-ERManI interaction. In addition, functional studies show that inactivation of the catalytic sites by site-directed mutagenesis disrupts the ERManI activity. These studies identify ERManI as a critical GH47 α-mannosidase in the ER-associated protein degradation pathway that initiates the Env degradation and suggests that its catalytic domain and enzymatic activity play an important role in this process.
authors.affiliation: From the Harbin Veterinary Research Institute, CAAS-Michigan State University Joint Laboratory of Innate Immunity, State Key Laboratory of Veterinary Biotechnology, Chinese Academy of Agricultural Sciences, Harbin, 150001, China, BEACON Center for the Study of Evolution in Action and Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan 48824.
authors.forename: Tao
authors.initials: T
authors.lastname: Zhou
authors.affiliation: BEACON Center for the Study of Evolution in Action and Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan 48824.
authors.forename: Dylan A
authors.initials: DA
authors.lastname: Frabutt
authors.affiliation: Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia 30602, and.
authors.forename: Kelley W
authors.initials: KW
authors.lastname: Moremen
authors.affiliation: From the Harbin Veterinary Research Institute, CAAS-Michigan State University Joint Laboratory of Innate Immunity, State Key Laboratory of Veterinary Biotechnology, Chinese Academy of Agricultural Sciences, Harbin, 150001, China, BEACON Center for the Study of Evolution in Action and Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan 48824 zhengyo@msu.edu.
authors.forename: Yong-Hui
authors.initials: YH
authors.lastname: Zheng
mesh_terms: D015153:Blotting, Western; D064113:CRISPR-Cas Systems; D002135:Calcium-Binding Proteins / Q000235:genetics / Q000378:metabolism; D002460:Cell Line; D004721:Endoplasmic Reticulum / Q000378:metabolism* / Q000821:virology; D060746:Endoplasmic Reticulum-Associated Degradation; D006023:Glycoproteins / Q000235:genetics / Q000378:metabolism; D057809:HEK293 Cells; D015497:HIV-1 / Q000378:metabolism* / Q000502:physiology; D054884:Host-Pathogen Interactions; D006801:Humans; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism; D008361:Mannosidases / Q000235:genetics / Q000378:metabolism; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D009154:Mutation; D011485:Protein Binding; D059748:Proteolysis; D018079:Receptors, GABA / Q000235:genetics / Q000378:metabolism; D043323:alpha-Mannosidase / Q000235:genetics / Q000378:metabolism*; D054299:env Gene Products, Human Immunodeficiency Virus / Q000378:metabolism*
chemical_list: D002135:Calcium-Binding Proteins; C486654:EDEM1 protein, human; D006023:Glycoproteins; D007527:Isoenzymes; D008565:Membrane Proteins; D018079:Receptors, GABA; C499229:TSPO protein, human; D054299:env Gene Products, Human Immunodeficiency Virus; C568343:MAN1B1 protein, human; D008361:Mannosidases; C497155:EDEM2 protein, human; C573113:EDEM3 protein, human; D043323:alpha-Mannosidase
keywords: endoplasmic reticulum stress (ER stress); endoplasmic-reticulum-associated protein degradation (ERAD); glycoprotein; glycoprotein biosynthesis; human immunodeficiency virus (HIV); protein degradation; unfolded protein response (UPR); viral protein