A casein-kinase-2-related protein kinase is tightly associated with the large T antigen of simian virus 40.
The simian virus 40 (SV40) large T antigen is a multifunctional protein involved in SV40 cell transformation and lytic virus infection. Some of its activities are regulated by interaction with cellular proteins and/or by phosphorylation of T antigen by various protein kinases. In this study, we show that immuno-purified T antigen from SV40-transformed cells and from baculovirus-infected insect cells is tightly associated with a protein kinase that phosphorylates T antigen in vitro. In the presence of heparin or a peptide resembling a protein kinase CK2 recognition site, the phosphorylation of T antigen by the associated kinase is reduced whereas a p34cdc2-kinase-specific peptide has no influence. In addition, the T-antigen-associated protein kinase can use GTP and ATP as phosphate donors. These properties together with the observation that immunopurified T antigen can be phosphorylated by the addition of protein kinase CK2 suggest that at least one of the T-antigen-associated protein kinases is CK2 or a protein-kinase-CK2-related enzyme. The association of recombinant CK2 with T antigen was strongly confirmed by in vitro binding studies. Experiments with temperature-sensitive SV40-transformed cells provide evidence for a close correlation between cell transformation and phosphorylation of T antigen by the associated protein kinase.
Götz
C
C
Department of Medical Biochemistry, University of the Saarland, Homburg, Germany.
Koenig
M G
MG
Issinger
O G
OG
Montenarh
M
M
D000595:Amino Acid Sequence; D000952:Antigens, Polyomavirus Transforming / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D047390:Casein Kinase II; D002461:Cell Line, Transformed; D002472:Cell Transformation, Viral; D006801:Humans; D008969:Molecular Sequence Data; D009154:Mutation; D010455:Peptides / Q000737:chemistry; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism; D013539:Simian virus 40 / Q000235:genetics / Q000276:immunology; D013379:Substrate Specificity; D013696:Temperature
D000952:Antigens, Polyomavirus Transforming; D010455:Peptides; D011994:Recombinant Proteins; D047390:Casein Kinase II; D017346:Protein Serine-Threonine Kinases