Mutations which affect the inhibition of protein phosphatase 2A by simian virus 40 small-t antigen in vitro decrease viral transformation.
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.
Mungre
S
S
Department of Microbiology-Immunology, Northwestern University, Chicago, Illinois 60611-3008.
Enderle
K
K
Turk
B
B
Porrás
A
A
Wu
Y Q
YQ
Mumby
M C
MC
Rundell
K
K
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
D017502:Adenovirus E2 Proteins; D000952:Antigens, Polyomavirus Transforming; D010749:Phosphoprotein Phosphatases; D054648:Protein Phosphatase 2; D003545:Cysteine