When cells become transformed by Rous sarcoma virus (RSV) they undergo numerous biochemical and regulatory changes which collectively constitute the """"""""transformed phenotype."""""""" All the manifestations of the transformed phenotype are dependent on the continuous activity of the viral transforming protein, pp60src, which has a tyrosine-specific protein kinase actvity. Genetic evidence indicates that pp60src has severa physiologically significant cellular targets with which it interacts to generate the transformed phenotype, and direct biochemical analysis reveals that numerous proteins become phosphorylated on tyrosine during transformatin by RSV. However, it is not know which of the tyrosine-phosphorylated proteins are physiologically significant targets nor what role these phosphorylations play in the genesis of the transformed phenotype. In this application, we propose a biochemical and genetic analysis of the intermediate steps leading from tyrosine phosphorylation by pp60src to the transformed phenotype. to simplify this analysis we will focus on biochemical and regulatory events which are shared by mitogen-treated and RSV-transformed cells: 1. We will isolate cellular variants which are altered in their response to pp60src or mitogenic agents. Refractoriness to either increased growth or increased glucose transport will be used as the basis for selection. Such variants may carry mutations in genes coding for targets of pp60src. 2. We will purify and characterize selected phosphotyrosine-containing proteins, with the first priority being to purify a protein of 42,000 Mr which is phosphorylated in both mitogen-stimulated cells and in RSV-transformed cells. The purified proteins will be used to raise monoclonal antibodies or antisera for studies on localization, for micro-injection and for direct functional studies. By taking the approach of biochemical genetics, we hope to define some of the intermediate steps in transformation by RSV and particularly the role of specific tyrosine phosphorylations in growth control and malignant transformation.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
5R01CA039076-03
Application #
3177840
Study Section
Cognition and Perception Study Section (CP)
Project Start
1984-06-01
Project End
1989-05-31
Budget Start
1986-06-01
Budget End
1987-05-31
Support Year
3
Fiscal Year
1986
Total Cost
Indirect Cost
Name
University of Virginia
Department
Type
Schools of Medicine
DUNS #
001910777
City
Charlottesville
State
VA
Country
United States
Zip Code
22904
Kumar, N Vinay; Eblen, Scott T; Weber, Michael J (2004) Identifying specific kinase substrates through engineered kinases and ATP analogs. Methods 32:389-97
Eblen, Scott T; Slack-Davis, Jill K; Tarcsafalvi, Adel et al. (2004) Mitogen-activated protein kinase feedback phosphorylation regulates MEK1 complex formation and activation during cellular adhesion. Mol Cell Biol 24:2308-17
Vomastek, Tomas; Schaeffer, Hans-Joerg; Tarcsafalvi, Adel et al. (2004) Modular construction of a signaling scaffold: MORG1 interacts with components of the ERK cascade and links ERK signaling to specific agonists. Proc Natl Acad Sci U S A 101:6981-6
Eblen, Scott T; Kumar, N Vinay; Shah, Kavita et al. (2003) Identification of novel ERK2 substrates through use of an engineered kinase and ATP analogs. J Biol Chem 278:14926-35
Bakin, Robert E; Gioeli, Daniel; Bissonette, Eric A et al. (2003) Attenuation of Ras signaling restores androgen sensitivity to hormone-refractory C4-2 prostate cancer cells. Cancer Res 63:1975-80
Bakin, Robert E; Gioeli, Daniel; Sikes, Robert A et al. (2003) Constitutive activation of the Ras/mitogen-activated protein kinase signaling pathway promotes androgen hypersensitivity in LNCaP prostate cancer cells. Cancer Res 63:1981-9
Carson, Jonathan P; Behnam, Marcelina; Sutton, Jennifer N et al. (2002) Smac is required for cytochrome c-induced apoptosis in prostate cancer LNCaP cells. Cancer Res 62:18-23
Gioeli, Daniel; Ficarro, Scott B; Kwiek, Jesse J et al. (2002) Androgen receptor phosphorylation. Regulation and identification of the phosphorylation sites. J Biol Chem 277:29304-14
Eblen, Scott T; Slack, Jill K; Weber, Michael J et al. (2002) Rac-PAK signaling stimulates extracellular signal-regulated kinase (ERK) activation by regulating formation of MEK1-ERK complexes. Mol Cell Biol 22:6023-33
Kulik, G; Carson, J P; Vomastek, T et al. (2001) Tumor necrosis factor alpha induces BID cleavage and bypasses antiapoptotic signals in prostate cancer LNCaP cells. Cancer Res 61:2713-9

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