title: YND1 interacts with CDC55 and is a novel mediator of E4orf4-induced toxicity.
abstract: Adenovirus E4orf4 (early region 4 open reading frame 4) protein induces protein phosphatase 2A-dependent non-classical apoptosis in mammalian cells and irreversible growth arrest in Saccharomyces cerevisiae. Oncogenic transformation sensitizes cells to E4orf4-induced cell death. To uncover additional components of the E4orf4 network required for induction of its unique mode of apoptosis, we used yeast genetics to select gene deletions conferring resistance to E4orf4. Deletion of YND1, encoding a yeast Golgi apyrase, conferred partial resistance to E4orf4. However, Ynd1p apyrase activity was not required for E4orf4-induced toxicity. Ynd1p and Cdc55p, the yeast protein phosphatase 2A-B subunit, contributed additively to E4orf4-induced toxicity. Furthermore, concomitant overexpression of one and deletion of the other was detrimental to yeast growth, demonstrating a functional interaction between the two proteins. YND1 and CDC55 also interacted genetically with CDC20 and CDH1/HCT1, encoding activating subunits of the anaphase-promoting complex/cyclosome. In addition to their functional interaction, Ynd1p and Cdc55p interacted physically, and this interaction was disrupted by E4orf4, which remained associated with both proteins. The results suggested that Ynd1p and Cdc55p share a common downstream target whose balanced modulation by the two E4orf4 partners is crucial to viability. Disruption of this balance by E4orf4 may lead to cell death. NTPDase-4/Lalp70/UDPase, the closest mammalian homologue of Ynd1p, associated with E4orf4 in mammalian cells, suggesting that the results in yeast are relevant to the mammalian system.
authors.affiliation: The Gonda Center of Molecular Microbiology and The Rappaport Family Institute for Research in the Medical Sciences, Faculty of Medicine, Technion-Israel Institute of Technology, Bat Galim, Haifa, 31096, Israel.
authors.forename: Tsofnat
authors.initials: T
authors.lastname: Maoz
authors.forename: Roni
authors.initials: R
authors.lastname: Koren
authors.forename: Inbal
authors.initials: I
authors.lastname: Ben-Ari
authors.forename: Tamar
authors.initials: T
authors.lastname: Kleinberger
mesh_terms: D017504:Adenovirus E4 Proteins; D000705:Anaphase; D017209:Apoptosis; D001081:Apyrase / Q000378:metabolism*; D064199:Cdc20 Proteins; D018797:Cell Cycle Proteins / Q000378:metabolism*; D016923:Cell Death; D002460:Cell Line; D002471:Cell Transformation, Neoplastic; D004251:DNA Transposable Elements; D017353:Gene Deletion; D015966:Gene Expression Regulation, Fungal; D005822:Genetic Vectors; D005838:Genotype; D006056:Golgi Apparatus / Q000378:metabolism; D006801:Humans; D007091:Image Processing, Computer-Assisted; D015151:Immunoblotting; D047468:Immunoprecipitation; D009154:Mutation; D016366:Open Reading Frames; D010957:Plasmids / Q000378:metabolism; D011485:Protein Binding; D054648:Protein Phosphatase 2; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism*; D015398:Signal Transduction; D008941:Spindle Apparatus; D014764:Viral Proteins / Q000235:genetics* / Q000378:metabolism*
chemical_list: D017504:Adenovirus E4 Proteins; C577495:CDC20 protein, S cerevisiae; C071246:CDC55 protein, S cerevisiae; D064199:Cdc20 Proteins; D018797:Cell Cycle Proteins; D004251:DNA Transposable Elements; C121517:E4orf4 protein, adenovirus; D029701:Saccharomyces cerevisiae Proteins; D014764:Viral Proteins; D054648:Protein Phosphatase 2; D001081:Apyrase; C506070:Ynd1 protein, S cerevisiae