Protein phosphatase 2A dephosphorylates simian virus 40 large T antigen specifically at residues involved in regulation of DNA-binding activity.
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.
Scheidtmann
K H
KH
Institut für Genetik, Universität Bonn, Federal Republic of Germany.
Virshup
D M
DM
Kelly
T J
TJ
D000818:Animals; D000957:Antigens, Viral, Tumor / Q000276:immunology*; D002478:Cells, Cultured; D004279:DNA, Viral / Q000378:metabolism*; D015180:Electrophoresis, Gel, Two-Dimensional; D000882:Haplorhini; D010749:Phosphoprotein Phosphatases / Q000378:metabolism*; D010766:Phosphorylation; D054648:Protein Phosphatase 2; D013539:Simian virus 40 / Q000201:enzymology / Q000235:genetics / Q000276:immunology*
D000957:Antigens, Viral, Tumor; D004279:DNA, Viral; D010749:Phosphoprotein Phosphatases; D054648:Protein Phosphatase 2