title: Identification of paramyxovirus V protein residues essential for STAT protein degradation and promotion of virus replication.
abstract: Some paramyxovirus V proteins induce STAT protein degradation, and the amino acids essential for this process in the human parainfluenza virus type 2 (hPIV2) V protein have been studied. Various recombinant hPIV2s and cell lines constitutively expressing various mutant V proteins were generated. We found that V proteins with replacement of Cys residues of the Cys cluster were still able to bind STATs but were unable to induce their degradation. The hPIV2 V protein binds STATs via a W-(X)3-W-(X)9-W Trp motif located just upstream of the Cys cluster. Replacements of two or more Trp residues in this motif resulted in a failure to form a V/STAT2 complex. We have also identified two Phe residues of the hPIV2 V protein that are essential for STAT degradation, namely, Phe207, lying within the Cys cluster, and Phe143, in the P/V common region of the protein. Interestingly, infection of BHK cells with hPIV2 led to the specific degradation of STAT1 and not STAT2. Other evidence for the cell species specificity of hPIV2-induced STAT degradation is presented. Finally, a V-minus hPIV2, which can express only the P protein from its P gene, was generated and partially characterized. In contrast to V-minus viruses of other paramyxovirus genera, this V-minus rubulavirus was highly debilitated, and its growth even in Vero cells was very limited. The structural rubulavirus V proteins, as expected, are thus clearly important in promoting virus growth, independent of their anti-interferon (IFN) activity. Interestingly, many of the residues that are essential for anti-IFN activity, e.g., the Cys of this cluster and Phe207 within this cluster, as well as the Trp of this motif, are also essential for promoting virus growth.
authors.affiliation: Department of Microbiology, Mie University School of Medicine, Tsu-shi, Mie Prefecture, Japan. nishio@doc.medic.mie-u.ac.jp
authors.forename: Machiko
authors.initials: M
authors.lastname: Nishio
authors.forename: Masato
authors.initials: M
authors.lastname: Tsurudome
authors.forename: Morihiro
authors.initials: M
authors.lastname: Ito
authors.forename: Dominique
authors.initials: D
authors.lastname: Garcin
authors.forename: Daniel
authors.initials: D
authors.lastname: Kolakofsky
authors.forename: Yasuhiko
authors.initials: Y
authors.lastname: Ito
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D002460:Cell Line; D045744:Cell Line, Tumor; D002522:Chlorocebus aethiops; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D017930:Genes, Reporter; D006367:HeLa Cells; D006801:Humans; D008969:Molecular Sequence Data; D010252:Paramyxoviridae / Q000235:genetics* / Q000254:growth & development; D010957:Plasmids / Q000235:genetics; D011485:Protein Binding; D050795:STAT2 Transcription Factor; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D015534:Trans-Activators / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D014709:Vero Cells; D014764:Viral Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism
chemical_list: D004268:DNA-Binding Proteins; D050795:STAT2 Transcription Factor; C494084:STAT2 protein, human; D015534:Trans-Activators; C502891:V protein, Paramyxovirus; D014764:Viral Proteins