title: Mutations which affect the inhibition of protein phosphatase 2A by simian virus 40 small-t antigen in vitro decrease viral transformation.
abstract: Three independent point mutations within residues 97 to 103 of the simian virus 40-small-t antigen (small-t) greatly reduced the ability of purified small-t to inhibit protein phosphatase 2A in vitro. These mutations affected the interaction of small-t antigen with the protein phosphatase 2A A subunit translated in vitro, and a peptide from the region identified by these mutations released the A subunit from immune complexes. When introduced into virus, the mutations eliminated the ability of small-t to enhance viral transformation of growth-arrested rat F111 cells. In contrast, the mutant small-t antigens were unimpaired in the transactivation of the adenovirus E2 promoter, an activity which was reduced by a double mutation in small-t residues 43 and 45.
authors.affiliation: Department of Microbiology-Immunology, Northwestern University, Chicago, Illinois 60611-3008.
authors.forename: S
authors.initials: S
authors.lastname: Mungre
authors.forename: K
authors.initials: K
authors.lastname: Enderle
authors.forename: B
authors.initials: B
authors.lastname: Turk
authors.forename: A
authors.initials: A
authors.lastname: Porrás
authors.forename: Y Q
authors.initials: YQ
authors.lastname: Wu
authors.forename: M C
authors.initials: MC
authors.lastname: Mumby
authors.forename: K
authors.initials: K
authors.lastname: Rundell
mesh_terms: D017502:Adenovirus E2 Proteins / Q000235:genetics; D000595:Amino Acid Sequence; D000952:Antigens, Polyomavirus Transforming / Q000235:genetics* / Q000378:metabolism; D002472:Cell Transformation, Viral / Q000235:genetics*; D003545:Cysteine / Q000235:genetics; D004252:DNA Mutational Analysis; D008969:Molecular Sequence Data; D010749:Phosphoprotein Phosphatases / Q000378:metabolism*; D011401:Promoter Regions, Genetic / Q000235:genetics; D011485:Protein Binding; D014176:Protein Biosynthesis; D054648:Protein Phosphatase 2; D013539:Simian virus 40 / Q000235:genetics*; D015533:Transcriptional Activation
chemical_list: D017502:Adenovirus E2 Proteins; D000952:Antigens, Polyomavirus Transforming; D010749:Phosphoprotein Phosphatases; D054648:Protein Phosphatase 2; D003545:Cysteine