Cellular proteins which can specifically associate with simian virus 40 small t antigen.
When crude, radiolabeled extracts of various cells were applied to homogeneous simian virus 40 small t antigen-Sepharose adsorbents, three cell proteins (57, 32, and 20 kilodaltons [kDa]) bound specifically. Each also bound to an insoluble, truncated t derivative composed of the COOH-terminal 123 residues of the protein. The binding of these proteins was greatly inhibited after reduction and alkylation of the t ligand. Therefore, some element of native conformation, but not all of the primary structure of t, is necessary for this binding property, which may constitute a discrete, in vitro biochemical function of this protein. Results of cell fractionation experiments suggested that the 57- and 32-kDa proteins are nonnuclear cell constituents, whereas the 20-kDa protein was closely associated with a detergent-washed nuclear fraction. Specific immunoblotting and comparative partial proteolytic digestion analyses indicated that the 57-kDa protein is tubulin, a major component of the cytoskeleton. In this regard, t and tubulin were observed to coimmunoprecipitate from crude cell extracts after incubation with monospecific anti-t antibody. Therefore, it is possible that t and tubulin interact in vivo.
D000818:Animals; D000952:Antigens, Polyomavirus Transforming; D000957:Antigens, Viral, Tumor; D002458:Cell Fractionation; D002460:Cell Line; D002467:Cell Nucleus / Q000032:analysis; D008970:Molecular Weight; D009856:Oncogene Proteins, Viral; D011506:Proteins / Q000378:metabolism*; D013539:Simian virus 40 / Q000276:immunology*; D014404:Tubulin / Q000378:metabolism*
D000952:Antigens, Polyomavirus Transforming; D000957:Antigens, Viral, Tumor; D009856:Oncogene Proteins, Viral; D011506:Proteins; D014404:Tubulin