title: Signal peptide cleavage from GP3 enabled by removal of adjacent glycosylation sites does not impair replication of equine arteritis virus in cell culture, but the hydrophobic C-terminus is essential.
abstract: The disulphide-linked GP2/3/4 spike of equine arteritis virus (EAV) is essential for virus entry. We showed recently that in transfected cells carbohydrates attached adjacent to the signal peptide of GP3 inhibit cleavage. Here we confirm this unique phenomenon in recombinant viruses with disabled glycosylation sites. Surprisingly, the infectivity of EAV containing GP3 with cleaved signal peptide was not impaired and GP3 with cleaved signal peptide associates with GP2/4 in virus particles. In contrast, viruses containing GP3 with deleted hydrophobic C-terminus rapidly reverted back to wild type. The data support our model that the signal peptide is exposed to the lumen of the ER and the C-terminus peripherally attaches GP3 to membranes.
authors.affiliation: Institut für Virologie, Veterinärmedizin, Freie Universität Berlin, Germany.
authors.forename: Anna Karolina
authors.initials: AK
authors.lastname: Matczuk
authors.affiliation: Institut für Virologie, Veterinärmedizin, Freie Universität Berlin, Germany. Electronic address: mveit@zedat.fu-berlin.de.
authors.forename: Michael
authors.initials: M
authors.lastname: Veit
mesh_terms: D000818:Animals; D002460:Cell Line; D006224:Cricetinae; D007240:Equartevirus / Q000502:physiology*; D006031:Glycosylation; D008954:Models, Biological; D021382:Protein Sorting Signals; D059748:Proteolysis; D014759:Viral Envelope Proteins / Q000378:metabolism*; D019562:Viral Load; D010948:Viral Plaque Assay; D014779:Virus Replication
chemical_list: C468294:GP3 protein, equine arteritis virus; D021382:Protein Sorting Signals; D014759:Viral Envelope Proteins
keywords: Arterivirus; Equine arteritis virus; GP3; Glycosylation; Membrane topology; Signal peptide