title: Ubiquitin depletion and dominant-negative VPS4 inhibit rhabdovirus budding without affecting alphavirus budding.
abstract: The budding reactions of a number of enveloped viruses use the cellular machinery involved in the formation of the luminal vesicles of endosomal multivesicular bodies (MVB). Budding of these viruses is dependent on the presence of specific late-domain motifs in membrane-associated viral proteins. Such budding reactions usually involve ubiquitin and are blocked by expression of an ATPase-deficient form of VPS4, a cellular AAA+ ATPase believed to be required late in the MVB pathway for the disassembly/release of the MVB machinery. Here we examined the role of the MVB pathway in the budding of the late-domain-containing rhabdovirus vesicular stomatitis virus (VSV) and the alphavirus Semliki Forest virus (SFV). We tested early and late steps in the MVB pathway by depleting ubiquitin with the proteasome inhibitor MG-132 and by using cell lines inducibly expressing VPS4A or VPS4B protein. As previously shown, VSV budding was strongly dependent on ubiquitin. In contrast to the findings of previous studies with VPS4A, expression of ATPase-deficient mutants of either VPS4A or VPS4B inhibited VSV budding. Inhibition by VPS4 required the presence of the PPPY late domain on the VSV matrix protein and resulted in the accumulation of nonreleased VSV particles at the plasma membrane. In contrast, SFV budding was independent of both ubiquitin and the activity of VPS4, perhaps reflecting the important role of the highly organized envelope protein lattice during alphavirus budding.
authors.affiliation: Department of Cell Biology, Albert Einstein College of Medicine, Bronx, New York 10461, USA.
authors.forename: Gwen M
authors.initials: GM
authors.lastname: Taylor
authors.forename: Phyllis I
authors.initials: PI
authors.lastname: Hanson
authors.forename: Margaret
authors.initials: M
authors.lastname: Kielian
mesh_terms: D000074183:ATPases Associated with Diverse Cellular Activities; D000251:Adenosine Triphosphatases / Q000235:genetics / Q000378:metabolism*; D000524:Alphavirus / Q000235:genetics / Q000254:growth & development / Q000378:metabolism / Q000472:pathogenicity; D000818:Animals; D002460:Cell Line / Q000648:ultrastructure / Q000821:virology; D006224:Cricetinae; D056827:Endosomal Sorting Complexes Required for Transport; D011992:Endosomes / Q000378:metabolism / Q000648:ultrastructure*; D006801:Humans; D007976:Leupeptins / Q000494:pharmacology; D008854:Microscopy, Electron; D012209:Rhabdoviridae / Q000235:genetics / Q000254:growth & development / Q000378:metabolism / Q000472:pathogenicity; D012672:Semliki forest virus / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism / Q000472:pathogenicity; D025801:Ubiquitin / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D025262:Vacuolar Proton-Translocating ATPases; D033921:Vesicular Transport Proteins / Q000235:genetics / Q000378:metabolism*; D018116:Vesiculovirus / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism / Q000472:pathogenicity; D019065:Virus Assembly
chemical_list: D056827:Endosomal Sorting Complexes Required for Transport; D007976:Leupeptins; D025801:Ubiquitin; D033921:Vesicular Transport Proteins; D000251:Adenosine Triphosphatases; D025262:Vacuolar Proton-Translocating ATPases; D000074183:ATPases Associated with Diverse Cellular Activities; C490305:VPS4A protein, human; C072553:benzyloxycarbonylleucyl-leucyl-leucine aldehyde