Localization of the phosphorylations of polyomavirus large T antigen.
AUTOR(ES)
Bockus, B J
RESUMO
Polyomavirus large T antigen is phosphorylated on both serine and threonine residues at a ratio of approximately 6 to 1. This phosphorylation could be resolved into a series of nine Staphylococcus aureus V8 phosphopeptides. All of these were found in an N-terminal chymotryptic fragment with a molecular weight of 57,000. A C-terminal formic acid fragment of 50,000-molecular-weight lacked phosphate. Therefore, unlike simian virus 40 large T antigen, polyomavirus large T antigen has no significant C-terminal phosphorylation. Limited V8 and hydroxylamine cleavage showed that the phosphorylations can be localized to two different portions of the molecule. A significant fraction of the phosphate was localized in the N-terminal portion of the molecule before residue 183. Within this region V8 peptides 4, 8, and 9 represented phosphorylations that were more proximal, while peptides 1, 2, and 3 included more distal phosphorylations. None of these phosphorylations appeared analogous to those of simian virus 40 large T antigen. V8 phosphopeptides 5 and 7 were more distal and could be distinguished in biological experiments from the N-terminal phosphorylations. Formic acid mapping suggested that much, if not all, of this phosphorylation is located between residues 257 and 285.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=254076Documentos Relacionados
- Mapping of phosphorylation sites in polyomavirus large T antigen.
- Cyclin-dependent kinase regulation of the replication functions of polyomavirus large T antigen.
- Determination of the origin-specific DNA-binding domain of polyomavirus large T antigen.
- Characterization of an immortalizing N-terminal domain of polyomavirus large T antigen.
- Gene targeting in rat embryo fibroblasts promoted by the polyomavirus large T antigen.