title: Phenotypes of vesicular stomatitis virus mutants with mutations in the PSAP motif of the matrix protein.
abstract: Vesicular stomatitis virus (VSV) matrix protein (M) has a flexible amino-terminal part that recruits cellular partners. It contains a dynamin-binding site that is required for efficient virus assembly, and two motifs, (24)PPPY(27) and (37)PSAP(40), that constitute potential late domains. Late domains are present in proteins of several enveloped viruses and are involved in the ultimate step of the budding process (i.e. fission between viral and cellular membranes). In baby hamster kidney (BHK)-21 cells, it has been demonstrated that the (24)PPPY(27) motif binds the Nedd4 (neuronal precursor cell-expressed developmentally downregulated 4) E3 ubiquitin ligase for efficient virus budding and that the (37)PSAP(40) motif, although conserved among M proteins of vesiculoviruses, does not possess late-domain activity. In this study, we have re-examined the contribution of the PSAP motif to VSV budding. First, we demonstrate that VSV M indeed binds TSG101 [tumour susceptibility gene 101; a component of the ESCRT1 (endosomal sorting complex required for transport 1)] through its PSAP motif. Second, we analysed the phenotype of several recombinant mutants. We show that a double mutant with point mutations in both the PSAP and the PPPY motifs is impaired compared with a single mutant in the PPPY motif, indicating that the PSAP motif partially compensates for the lack of the PPPY motif. Mutants' phenotypes depend on cell lines: in CERA (chicken embryo-related, Alger clone) cells, a recombinant virus with a single mutation in the PSAP motif was impaired compared with the wild type, and a mutant with a single mutation in the dynamin-binding motif was much less impaired in Vero cells than in BSR (clones of BHK-21) cells. These results have implications for the VSV budding pathway that will be discussed.
authors.affiliation: Centre de Recherche de Gif, Laboratoire de Virologie Moléculaire et Structurale, CNRS (UPR 3296), 91198 Gif sur Yvette Cedex, France.
authors.forename: Linda
authors.initials: L
authors.lastname: Obiang
authors.affiliation: Centre de Recherche de Gif, Laboratoire de Virologie Moléculaire et Structurale, CNRS (UPR 3296), 91198 Gif sur Yvette Cedex, France.
authors.forename: Hélène
authors.initials: H
authors.lastname: Raux
authors.affiliation: Centre de Recherche de Gif, Laboratoire de Virologie Moléculaire et Structurale, CNRS (UPR 3296), 91198 Gif sur Yvette Cedex, France.
authors.forename: Malika
authors.initials: M
authors.lastname: Ouldali
authors.affiliation: Centre de Recherche de Gif, Laboratoire de Virologie Moléculaire et Structurale, CNRS (UPR 3296), 91198 Gif sur Yvette Cedex, France.
authors.forename: Danielle
authors.initials: D
authors.lastname: Blondel
authors.affiliation: Centre de Recherche de Gif, Laboratoire de Virologie Moléculaire et Structurale, CNRS (UPR 3296), 91198 Gif sur Yvette Cedex, France.
authors.forename: Yves
authors.initials: Y
authors.lastname: Gaudin
mesh_terms: D000818:Animals; D002460:Cell Line; D006224:Cricetinae; D034281:Dynamins / Q000378:metabolism; D056827:Endosomal Sorting Complexes Required for Transport / Q000378:metabolism; D006801:Humans; D008854:Microscopy, Electron; D016297:Mutagenesis, Site-Directed; D009154:Mutation / Q000235:genetics / Q000502:physiology; D000075702:Nedd4 Ubiquitin Protein Ligases; D010641:Phenotype; D044767:Ubiquitin-Protein Ligases / Q000378:metabolism; D054243:Vesicular Stomatitis / Q000378:metabolism / Q000821:virology; D018116:Vesiculovirus / Q000235:genetics* / Q000502:physiology; D014763:Viral Matrix Proteins / Q000235:genetics* / Q000502:physiology; D019065:Virus Assembly / Q000235:genetics / Q000502:physiology
chemical_list: D056827:Endosomal Sorting Complexes Required for Transport; C094460:M protein, Vesicular stomatitis virus; D014763:Viral Matrix Proteins; D000075702:Nedd4 Ubiquitin Protein Ligases; C000618483:Nedd4 protein, human; D044767:Ubiquitin-Protein Ligases; D034281:Dynamins