title: Hepatitis E virus ORF3 is a functional ion channel required for release of infectious particles.
abstract: Hepatitis E virus (HEV) is the leading cause of enterically transmitted viral hepatitis globally. Of HEV's three ORFs, the function of ORF3 has remained elusive. Here, we demonstrate that via homophilic interactions ORF3 forms multimeric complexes associated with intracellular endoplasmic reticulum (ER)-derived membranes. HEV ORF3 shares several structural features with class I viroporins, and the function of HEV ORF3 can be maintained by replacing it with the well-characterized viroporin influenza A virus (IAV) matrix-2 protein. ORF3's ion channel function is further evidenced by its ability to mediate ionic currents when expressed in Xenopus laevis oocytes. Furthermore, we identified several positions in ORF3 critical for its formation of multimeric complexes, ion channel activity, and, ultimately, release of infectious particles. Collectively, our data demonstrate a previously undescribed function of HEV ORF3 as a viroporin, which may serve as an attractive target in developing direct-acting antivirals.
authors.affiliation: Department of Molecular Biology, Lewis Thomas Laboratory, Princeton University, Princeton, NJ 08544.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Ding
authors.affiliation: Department of Molecular Biology, Lewis Thomas Laboratory, Princeton University, Princeton, NJ 08544.
authors.forename: Brigitte
authors.initials: B
authors.lastname: Heller
authors.affiliation: Department of Pharmacology, Physiology and Neuroscience, Rutgers University, Newark, NJ 07103.
authors.forename: Juan M V
authors.initials: JM
authors.lastname: Capuccino
authors.affiliation: Department of Molecular Biology, Lewis Thomas Laboratory, Princeton University, Princeton, NJ 08544.
authors.forename: Bokai
authors.initials: B
authors.lastname: Song
authors.affiliation: Department of Molecular Biology, Lewis Thomas Laboratory, Princeton University, Princeton, NJ 08544.
authors.forename: Ila
authors.initials: I
authors.lastname: Nimgaonkar
authors.affiliation: Department of Molecular Biology, Lewis Thomas Laboratory, Princeton University, Princeton, NJ 08544.
authors.forename: Gabriela
authors.initials: G
authors.lastname: Hrebikova
authors.affiliation: Department of Pharmacology, Physiology and Neuroscience, Rutgers University, Newark, NJ 07103.
authors.forename: Jorge E
authors.initials: JE
authors.lastname: Contreras
authors.affiliation: Department of Molecular Biology, Lewis Thomas Laboratory, Princeton University, Princeton, NJ 08544; aploss@princeton.edu.
authors.forename: Alexander
authors.initials: A
authors.lastname: Ploss
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D000818:Animals; D004721:Endoplasmic Reticulum / Q000378:metabolism; D017353:Gene Deletion; D057809:HEK293 Cells; D056945:Hep G2 Cells; D016752:Hepatitis E virus / Q000502:physiology*; D006801:Humans; D007473:Ion Channels / Q000737:chemistry / Q000502:physiology*; D017136:Ion Transport; D009865:Oocytes; D018408:Patch-Clamp Techniques; D000072417:Protein Domains; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D013329:Structure-Activity Relationship; D014763:Viral Matrix Proteins / Q000502:physiology; D014764:Viral Proteins / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D057074:Virus Release / Q000502:physiology*; D014779:Virus Replication; D014982:Xenopus laevis
chemical_list: D007473:Ion Channels; C488936:M1 protein, Influenza A virus; C400973:ORF3 protein, Hepatitis E virus; D011993:Recombinant Fusion Proteins; D014763:Viral Matrix Proteins; D014764:Viral Proteins
keywords: drug development; hepatitis E; hepatitis E virus; virion release; viroporin