Abstract
The transforming protein of polyomavirus, middle T (mT), forms a complex with two cellular enzymes: the protein tyrosine kinase pp60c-src and a phosphatidylinositol (PtdIns) 3-kinase. A mutant virus, Py1178T, encodes an mT protein which associates with and activates pp60c-src to the same extent as the wild type but fails to associate with PtdIns 3-kinase. To investigate relationships between activation of pp60c-src, association of PtdIns 3-kinase, and cellular levels of the second messenger inositol 1,4,5-trisphosphate (InsP3), we examined the effects of wild-type and mutant mT proteins on inositol metabolism in rat and mouse fibroblasts. Expression of either wild-type or 1178T mT caused a 300 to 500% increase in the InsP3 level. Cells transformed by Rous sarcoma virus also showed similar increases in InsP3 levels. Mutant mT proteins which failed to activate pp60c-src (NG59 and 1387T) had no effect on InsP3 levels. Pulse-chase experiments with [3H]inositol showed that the turnover of phosphoinositides was increased in cells transformed by either wild-type polyomavirus or Py1178T as compared with the normal parent cell line. The turnover of inositol phosphates was unchanged upon transformation. These data indicate that cells expressing either wild-type or mutant 1178T mT or pp60v-src exhibit elevated levels of InsP3 because of activation of phospholipase C. This activation appears to depend, directly or indirectly, upon activation of pp60src protein kinase activity. Activation of pp60c-src and elevation of InsP3 content are not sufficient for full transformation. Full transformation also requires the association of mT-pp60c-src complexes with PtdIns 3-kinase.
Full text
PDF







Images in this article
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- BARTLETT G. R. Phosphorus assay in column chromatography. J Biol Chem. 1959 Mar;234(3):466–468. [PubMed] [Google Scholar]
- Benjamin T. L. Host range mutants of polyoma virus. Proc Natl Acad Sci U S A. 1970 Sep;67(1):394–399. doi: 10.1073/pnas.67.1.394. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Berridge M. J. Inositol trisphosphate and diacylglycerol: two interacting second messengers. Annu Rev Biochem. 1987;56:159–193. doi: 10.1146/annurev.bi.56.070187.001111. [DOI] [PubMed] [Google Scholar]
- Bolen J. B., Israel M. A. Middle tumor antigen of polyomavirus transformation-defective mutant NG59 is associated with pp60c-src. J Virol. 1985 Jan;53(1):114–119. doi: 10.1128/jvi.53.1.114-119.1985. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Bolen J. B., Thiele C. J., Israel M. A., Yonemoto W., Lipsich L. A., Brugge J. S. Enhancement of cellular src gene product associated tyrosyl kinase activity following polyoma virus infection and transformation. Cell. 1984 Oct;38(3):767–777. doi: 10.1016/0092-8674(84)90272-1. [DOI] [PubMed] [Google Scholar]
- Carmichael G. G., Schaffhausen B. S., Dorsky D. I., Oliver D. B., Benjamin T. L. Carboxy terminus of polyoma middle-sized tumor antigen is required for attachment to membranes, associated protein kinase activities, and cell transformation. Proc Natl Acad Sci U S A. 1982 Jun;79(11):3579–3583. doi: 10.1073/pnas.79.11.3579. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Carmichael G., Schaffhausen B. S., Mandel G., Liang T. J., Benjamin T. L. Transformation by polyoma virus is drastically reduced by substitution of phenylalanine for tyrosine at residue 315 of middle-sized tumor antigen. Proc Natl Acad Sci U S A. 1984 Feb;81(3):679–683. doi: 10.1073/pnas.81.3.679. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Cartwright C. A., Eckhart W., Simon S., Kaplan P. L. Cell transformation by pp60c-src mutated in the carboxy-terminal regulatory domain. Cell. 1987 Apr 10;49(1):83–91. doi: 10.1016/0092-8674(87)90758-6. [DOI] [PubMed] [Google Scholar]
- Cartwright C. A., Hutchinson M. A., Eckhart W. Structural and functional modification of pp60c-src associated with polyoma middle tumor antigen from infected or transformed cells. Mol Cell Biol. 1985 Oct;5(10):2647–2652. doi: 10.1128/mcb.5.10.2647. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Coughlin S. R., Escobedo J. A., Williams L. T. Role of phosphatidylinositol kinase in PDGF receptor signal transduction. Science. 1989 Mar 3;243(4895):1191–1194. doi: 10.1126/science.2466336. [DOI] [PubMed] [Google Scholar]
- Courtneidge S. A. Activation of the pp60c-src kinase by middle T antigen binding or by dephosphorylation. EMBO J. 1985 Jun;4(6):1471–1477. doi: 10.1002/j.1460-2075.1985.tb03805.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Courtneidge S. A., Heber A. An 81 kd protein complexed with middle T antigen and pp60c-src: a possible phosphatidylinositol kinase. Cell. 1987 Sep 25;50(7):1031–1037. doi: 10.1016/0092-8674(87)90169-3. [DOI] [PubMed] [Google Scholar]
- Courtneidge S. A., Smith A. E. Polyoma virus transforming protein associates with the product of the c-src cellular gene. Nature. 1983 Jun 2;303(5916):435–439. doi: 10.1038/303435a0. [DOI] [PubMed] [Google Scholar]
- Courtneidge S. A., Smith A. E. The complex of polyoma virus middle-T antigen and pp60c-src. EMBO J. 1984 Mar;3(3):585–591. doi: 10.1002/j.1460-2075.1984.tb01852.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Diringer H., Friis R. R. Changes in phosphatidylinositol metabolism correlated to growth state of normal and Rous sarcoma virus-transformed Japanese quail cells. Cancer Res. 1977 Sep;37(9):2979–2984. [PubMed] [Google Scholar]
- Downes C. P., Michell R. H. The polyphosphoinositide phosphodiesterase of erythrocyte membranes. Biochem J. 1981 Jul 15;198(1):133–140. doi: 10.1042/bj1980133. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Fain J. N., Wallace M. A., Wojcikiewicz R. J. Evidence for involvement of guanine nucleotide-binding regulatory proteins in the activation of phospholipases by hormones. FASEB J. 1988 Jul;2(10):2569–2574. doi: 10.1096/fasebj.2.10.2838362. [DOI] [PubMed] [Google Scholar]
- Feunteun J., Sompayrac L., Fluck M., Benjamin T. Localization of gene functions in polyoma virus DNA. Proc Natl Acad Sci U S A. 1976 Nov;73(11):4169–4173. doi: 10.1073/pnas.73.11.4169. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Freeman A. E., Gilden R. V., Vernon M. L., Wolford R. G., Hugunin P. E., Huebner R. J. 5-Bromo-2'-deoxyuridine potentiation of transformation of rat-embryo cells induced in vitro by 3-methylcholanthrene: induction of rat leukemia virus gs antigen in transformed cells. Proc Natl Acad Sci U S A. 1973 Aug;70(8):2415–2419. doi: 10.1073/pnas.70.8.2415. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Irvine R. F., Moor R. M., Pollock W. K., Smith P. M., Wreggett K. A. Inositol phosphates: proliferation, metabolism and function. Philos Trans R Soc Lond B Biol Sci. 1988 Jul 26;320(1199):281–298. doi: 10.1098/rstb.1988.0077. [DOI] [PubMed] [Google Scholar]
- Jackowski S., Rettenmier C. W., Sherr C. J., Rock C. O. A guanine nucleotide-dependent phosphatidylinositol 4,5-diphosphate phospholipase C in cells transformed by the v-fms and v-fes oncogenes. J Biol Chem. 1986 Apr 15;261(11):4978–4985. [PubMed] [Google Scholar]
- Kaplan D. R., Whitman M., Schaffhausen B., Pallas D. C., White M., Cantley L., Roberts T. M. Common elements in growth factor stimulation and oncogenic transformation: 85 kd phosphoprotein and phosphatidylinositol kinase activity. Cell. 1987 Sep 25;50(7):1021–1029. doi: 10.1016/0092-8674(87)90168-1. [DOI] [PubMed] [Google Scholar]
- Kaplan D. R., Whitman M., Schaffhausen B., Raptis L., Garcea R. L., Pallas D., Roberts T. M., Cantley L. Phosphatidylinositol metabolism and polyoma-mediated transformation. Proc Natl Acad Sci U S A. 1986 Jun;83(11):3624–3628. doi: 10.1073/pnas.83.11.3624. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Kato M., Kawai S., Takenawa T. Altered signal transduction in erbB-transformed cells. Implication of enhanced inositol phospholipid metabolism in erbB-induced transformation. J Biol Chem. 1987 Apr 25;262(12):5696–5704. [PubMed] [Google Scholar]
- Lips D. L., Majerus P. W., Gorga F. R., Young A. T., Benjamin T. L. Phosphatidylinositol 3-phosphate is present in normal and transformed fibroblasts and is resistant to hydrolysis by bovine brain phospholipase C II. J Biol Chem. 1989 May 25;264(15):8759–8763. [PubMed] [Google Scholar]
- Macara I. G., Marinetti G. V., Balduzzi P. C. Transforming protein of avian sarcoma virus UR2 is associated with phosphatidylinositol kinase activity: possible role in tumorigenesis. Proc Natl Acad Sci U S A. 1984 May;81(9):2728–2732. doi: 10.1073/pnas.81.9.2728. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Martins T. J., Sugimoto Y., Erikson R. L. Dissociation of inositol trisphosphate from diacylglycerol production in Rous sarcoma virus-transformed fibroblasts. J Cell Biol. 1989 Feb;108(2):683–691. doi: 10.1083/jcb.108.2.683. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Nishizuka Y. The role of protein kinase C in cell surface signal transduction and tumour promotion. Nature. 1984 Apr 19;308(5961):693–698. doi: 10.1038/308693a0. [DOI] [PubMed] [Google Scholar]
- Raptis L., Lamfrom H., Benjamin T. L. Regulation of cellular phenotype and expression of polyomavirus middle T antigen in rat fibroblasts. Mol Cell Biol. 1985 Sep;5(9):2476–2486. doi: 10.1128/mcb.5.9.2476. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Schlegel R., Benjamin T. L. Cellular alterations dependent upon the polyoma virus Hr-t function: separation of mitogenic from transforming capacities. Cell. 1978 Jul;14(3):587–599. doi: 10.1016/0092-8674(78)90244-1. [DOI] [PubMed] [Google Scholar]
- Southern P. J., Berg P. Transformation of mammalian cells to antibiotic resistance with a bacterial gene under control of the SV40 early region promoter. J Mol Appl Genet. 1982;1(4):327–341. [PubMed] [Google Scholar]
- Sugimoto Y., Whitman M., Cantley L. C., Erikson R. L. Evidence that the Rous sarcoma virus transforming gene product phosphorylates phosphatidylinositol and diacylglycerol. Proc Natl Acad Sci U S A. 1984 Apr;81(7):2117–2121. doi: 10.1073/pnas.81.7.2117. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Talmage D. A., Freund R., Young A. T., Dahl J., Dawe C. J., Benjamin T. L. Phosphorylation of middle T by pp60c-src: a switch for binding of phosphatidylinositol 3-kinase and optimal tumorigenesis. Cell. 1989 Oct 6;59(1):55–65. doi: 10.1016/0092-8674(89)90869-6. [DOI] [PubMed] [Google Scholar]
- Wahl M. I., Daniel T. O., Carpenter G. Antiphosphotyrosine recovery of phospholipase C activity after EGF treatment of A-431 cells. Science. 1988 Aug 19;241(4868):968–970. doi: 10.1126/science.2457254. [DOI] [PubMed] [Google Scholar]
- Wahl M. I., Olashaw N. E., Nishibe S., Rhee S. G., Pledger W. J., Carpenter G. Platelet-derived growth factor induces rapid and sustained tyrosine phosphorylation of phospholipase C-gamma in quiescent BALB/c 3T3 cells. Mol Cell Biol. 1989 Jul;9(7):2934–2943. doi: 10.1128/mcb.9.7.2934. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Whitman M., Downes C. P., Keeler M., Keller T., Cantley L. Type I phosphatidylinositol kinase makes a novel inositol phospholipid, phosphatidylinositol-3-phosphate. Nature. 1988 Apr 14;332(6165):644–646. doi: 10.1038/332644a0. [DOI] [PubMed] [Google Scholar]
- Whitman M., Kaplan D. R., Schaffhausen B., Cantley L., Roberts T. M. Association of phosphatidylinositol kinase activity with polyoma middle-T competent for transformation. Nature. 1985 May 16;315(6016):239–242. doi: 10.1038/315239a0. [DOI] [PubMed] [Google Scholar]

