Binding of Polyomavirus Small T Antigen to Protein Phosphatase 2A Is Required for Elimination of p27 and Support of S-Phase Induction in Concert with Large T Antigen

• DOI: 10.1128/jvi.73.11.9266-9273.1999
• Publication Date: 2019-12-31T18:21:06Z
• Authors: Stefan Schüchner; Erhard Wintersberger
• Keywords: Cyclin-dependent kinase complex; Cyclin A2; Cyclin D; Cyclin E; Cyclin A; Retinoblastoma protein

ABSTRACT Although polyomavirus large T antigen readily transactivates S-phase-specific enzymes in serum-starved Swiss 3T3 mouse fibroblasts, it is incapable by itself to efficiently drive such cells into S phase. We describe here that this inability correlates with a weak proficiency of the viral protein induce synthesis cyclin A and E stimulate respective cyclin/cdk activities. Polyomavirus small antigen, which together supports S-phase induction, strongly contributes A. In addition, causes dramatic induction A- and, E-specific kinase activity. This latter function its competence provoke elimination inhibitor p27 Kip1 . An interaction phosphatase 2A essential for Hence, ability quiescent phase results from capacity transactivate DNA retinoblastoma-type proteins potential antigens E-dependent