Treatment of purified simian virus 40 large T antigen (LT) with protein phosphatase 2A stimulates LT-dependent DNA unwinding and replication (D.M. Virshup, M.G. Kauffman, and T.J. Kelly, EMBO J. 8: 3891-3898, 1989). The specificity of the catalytic subunit of protein phosphatase 2A toward LT was investigated by two-dimensional peptide mapping. Increasing amounts of phosphatase sequentially removed the phosphates from serine residues 120, 123, 677, and perhaps 679, residues which have been implicated in regulating the DNA-binding activity of LT.
ASJC Scopus subject areas
- Insect Science