Molecular chaperone function of the SV40 large T antigen.
The SV40 large T antigen (T antigen) is a potent viral oncogene capable of inducing tumours in test animals and transforming cells in culture. T antigen possesses multiple transforming functions that act in a cell-type dependent manner. One of these transforming functions requires a physical association between T antigen and the cellular tumour suppressor p53, while another requires T antigen binding to the retinoblastoma family of tumour suppressors. A third transforming function, <<Activity X>>, maps to the amino terminus of large T antigen, sequences also present in small t antigen. Our recent studies have shown that Activity X: (i) is a J-domain and that T antigen possesses the biochemical properties of a DnaJ molecular chaperone; (ii) must act in cis with the T antigen Rb-family binding motif to transform; and, (iii) must act in cis with some factor through its carboxy terminal half of T antigen, possibly p53, to transform.
Pipas
J M
JM
Department of Biological Sciences, University of Pittsburgh, Pennsylvania 15260, USA.
D000595:Amino Acid Sequence; D000818:Animals; D000952:Antigens, Polyomavirus Transforming / Q000502:physiology*; D002471:Cell Transformation, Neoplastic; D006801:Humans; D018832:Molecular Chaperones / Q000502:physiology*; D008969:Molecular Sequence Data; D017433:Protein Structure, Secondary; D017386:Sequence Homology, Amino Acid; D013539:Simian virus 40 / Q000472:pathogenicity*
D000952:Antigens, Polyomavirus Transforming; D018832:Molecular Chaperones