title: Old world arenaviruses enter the host cell via the multivesicular body and depend on the endosomal sorting complex required for transport.
abstract: The highly pathogenic Old World arenavirus Lassa virus (LASV) and the prototypic arenavirus lymphocytic choriomeningitis virus (LCMV) use α-dystroglycan as a cellular receptor and enter the host cell by an unusual endocytotic pathway independent of clathrin, caveolin, dynamin, and actin. Upon internalization, the viruses are delivered to acidified endosomes in a Rab5-independent manner bypassing classical routes of incoming vesicular trafficking. Here we sought to identify cellular factors involved in the unusual and largely unknown entry pathway of LASV and LCMV. Cell entry of LASV and LCMV required microtubular transport to late endosomes, consistent with the low fusion pH of the viral envelope glycoproteins. Productive infection with recombinant LCMV expressing LASV envelope glycoprotein (rLCMV-LASVGP) and LCMV depended on phosphatidyl inositol 3-kinase (PI3K) as well as lysobisphosphatidic acid (LBPA), an unusual phospholipid that is involved in the formation of intraluminal vesicles (ILV) of the multivesicular body (MVB) of the late endosome. We provide evidence for a role of the endosomal sorting complex required for transport (ESCRT) in LASV and LCMV cell entry, in particular the ESCRT components Hrs, Tsg101, Vps22, and Vps24, as well as the ESCRT-associated ATPase Vps4 involved in fission of ILV. Productive infection with rLCMV-LASVGP and LCMV also critically depended on the ESCRT-associated protein Alix, which is implicated in membrane dynamics of the MVB/late endosomes. Our study identifies crucial cellular factors implicated in Old World arenavirus cell entry and indicates that LASV and LCMV invade the host cell passing via the MVB/late endosome. Our data further suggest that the virus-receptor complexes undergo sorting into ILV of the MVB mediated by the ESCRT, possibly using a pathway that may be linked to the cellular trafficking and degradation of the cellular receptor.
authors.affiliation: Institute of Microbiology, University Hospital Center and University of Lausanne, Lausanne, Switzerland.
authors.forename: Giulia
authors.initials: G
authors.lastname: Pasqual
authors.forename: Jillian M
authors.initials: JM
authors.lastname: Rojek
authors.forename: Mark
authors.initials: M
authors.lastname: Masin
authors.forename: Jean-Yves
authors.initials: JY
authors.lastname: Chatton
authors.forename: Stefan
authors.initials: S
authors.lastname: Kunz
mesh_terms: D000074183:ATPases Associated with Diverse Cellular Activities; D000818:Animals; D001692:Biological Transport; D002460:Cell Line; D002522:Chlorocebus aethiops; D006224:Cricetinae; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D049030:Dystroglycans / Q000378:metabolism; D004705:Endocytosis; D056827:Endosomal Sorting Complexes Required for Transport / Q000235:genetics / Q000378:metabolism*; D011992:Endosomes / Q000378:metabolism; D057809:HEK293 Cells; D006801:Humans; D015151:Immunoblotting; D007836:Lassa virus / Q000472:pathogenicity*; D008217:Lymphocytic choriomeningitis virus / Q000472:pathogenicity*; D008246:Lysophospholipids / Q000378:metabolism; D050178:Monoglycerides / Q000378:metabolism; D057146:Multivesicular Bodies / Q000821:virology*; D009154:Mutation; D018129:Phosphatidylinositol Phosphates / Q000378:metabolism; D034622:RNA Interference; D060888:Real-Time Polymerase Chain Reaction; D011991:Receptors, Virus / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D014168:Transferrin / Q000378:metabolism; D025262:Vacuolar Proton-Translocating ATPases / Q000235:genetics / Q000378:metabolism; D014764:Viral Proteins / Q000235:genetics / Q000378:metabolism; D053586:Virus Internalization; D000099177:Tsg101 Protein
chemical_list: D000074183:ATPases Associated with Diverse Cellular Activities; D004268:DNA-Binding Proteins; D049030:Dystroglycans; D056827:Endosomal Sorting Complexes Required for Transport; D008246:Lysophospholipids; D050178:Monoglycerides; D018129:Phosphatidylinositol Phosphates; D011991:Receptors, Virus; D014157:Transcription Factors; D014168:Transferrin; D025262:Vacuolar Proton-Translocating ATPases; D014764:Viral Proteins; D000099177:Tsg101 Protein; C012786:bis(monoacylglyceryl)phosphate; C055525:phosphatidylinositol 3-phosphate; C490305:VPS4A protein, human