Tumor promoters accelerate the process of cellular transformation through alteration of normal cellular growth and differentiation processes. One approach that has yielded important information regarding the regulation of growth factor receptors and the mechanisms by which tumor promoters act is to study the interaction of tumor promoters with receptor systems. Thapsigargin is a protein kinase C-independent tumor promoter that has recently been shown to alter epidermal growth factor (EGF) receptor binding and kinase activity. Evidence suggests that the response of the receptor is due to activation by thapsigargin of a kinase that phosphorylates select sites on the EGF receptor that differ from those phosphorylated by protein kinase C. We now propose to identify these sites and to directly test their role in the action of thapsigargin through site-directed mutagenesis studies of the EGF receptor. We also plan to investigate the mechanism by which thapsigargin stimulates kinase activation. These studies provide a new approach to understanding the regulation of cellular receptors by exogenous agents, and will lead to the elucidation of new signal transduction pathways in the cell.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
5R01CA035541-09
Application #
3173132
Study Section
Chemical Pathology Study Section (CPA)
Project Start
1987-09-01
Project End
1995-11-30
Budget Start
1991-12-01
Budget End
1992-11-30
Support Year
9
Fiscal Year
1992
Total Cost
Indirect Cost
Name
University of Chicago
Department
Type
Schools of Medicine
DUNS #
225410919
City
Chicago
State
IL
Country
United States
Zip Code
60637
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Hershenson, M B; Chao, T S; Abe, M K et al. (1995) Histamine antagonizes serotonin and growth factor-induced mitogen-activated protein kinase activation in bovine tracheal smooth muscle cells. J Biol Chem 270:19908-13
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Chao, T S; Foster, D A; Rapp, U R et al. (1994) Differential Raf requirement for activation of mitogen-activated protein kinase by growth factors, phorbol esters, and calcium. J Biol Chem 269:7337-41
Hou, X; Johnson, A C; Rosner, M R (1994) Identification of an epidermal growth factor receptor transcriptional repressor. J Biol Chem 269:4307-12

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