Open AccessTumor promoters alter gene expression and protein phosphorylation in avian cells in culture.
Author(s) -
Andrei Laszlo,
Kathryn Radke,
Steven S. Chin,
Mina J. Bissell
Publication year - 1981
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.78.10.6241
Subject(s) - rous sarcoma virus , phosphorylation , microbiology and biotechnology , biology , kinase , proto oncogene tyrosine protein kinase src , gene , carcinogenesis , protein phosphorylation , gene expression , gene product , biochemistry , protein kinase a
We have investigated the effect of 12-O-tetradecanoylphorbol 13-acetate (TPA) on the synthesis and modification of polypeptides in normal avian cells and cells infected by wild-type and temperature-sensitive Rous sarcoma virus (RSV). Using two-dimensional gel electrophoresis, we have detected alterations in both the abundance of cellular polypeptides and in their phosphorylation that seem unique to TPA treatment. However, the state of phosphorylation of the major putative substrate for the action of the src gene-associated protein kinase, the 34- to 36-kilodalton protein, was not altered. Moreover, examination of the phosphorylated amino acid content of total cellular phosphoproteins revealed that the response to TPA was not associated with detectable increases in their phosphotyrosine content. These results make it unlikely that TPA acts by the activation of the phosphorylating activity of the cellular proto-src gene or by the activation of other cellular phosphotyrosine-specific kinases. We have shown previously that temperature-sensitive RSV-infected cells at nonpermissive temperature demonstrate an increased sensitivity to TPA treatment [Bissell, M. J., Hatie, C. & Calvin, M. (1979) Proc. Natl. Acad. Sci. USA 76, 348-352]. Our present results indicate that this is not due to reactivation of the phosphorylating activity of the defective src gene product or to its leakiness, and they lend support to the notion of multistep viral carcinogenesis.