The binding of epidermal growth factor (EGF) to its plasma membrane receptor initiates a broad array of cellular responses, ultimately culminating in mitosis. The receptor is a transmembrane glycoprotein of M/r approximately 170,000, the sequence of which has been deduced from the cDNA for the receptor. A second natural ligand for the EGF receptor is transforming growth factor-alpha (TGFalpha), which has sequence and 3-dimensional structural homology with EGF. When EGF or TGFalpha binds to the extracytoplasmic domain of the receptor, a protein tyrosine kinase within the cytoplasmic domain of the receptor is activated, and the receptor dimerizes. Activation of the kinase on binding of EGF or TGFalpha to the receptor is generally considered to be an important step in signal transduction; however, the ultimate biological responses to EGF and TGFalpha, while similar, are not identical. The long term goal of this project is to develop an in-depth understanding of the protein chemistry and enzymology of the EGF receptor as it relates to the mechanism of signal transduction. This proposal addresses this long term goal through three specific aims: (1) To identify residues of the receptor adjacent to bound EGF or TGFalpha by a strategy of affinity cross-linking of site-directed mutants of EGF or TGFalpha to the receptor and determination of the sites of cross-linking by protein microsequencing, thereby testing whether the differences in biological response to EGF and TGFalpha correlate to subtle differences in binding sites. (2) To identify receptor residues important in EGF and/or TGFalpha recognition by a strategy of selective site-directed mutagenesis of the receptor and quantitative EGF and TGFalpha binding assays of mutant receptors. (3) To identify residues within the ATP binding site of the receptor responsible for chemical and thermal inactivation of receptor kinase activity by site-directed mutagenesis and testing the resulting mutant receptors for altered properties of chemical and thermal inactivation.

National Institute of Health (NIH)
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Research Project (R01)
Project #
Application #
Study Section
Physiological Chemistry Study Section (PC)
Program Officer
Sato, Sheryl M
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
Vanderbilt University Medical Center
Schools of Arts and Sciences
United States
Zip Code
Ewald, Jonathan A; Wilkinson, John C; Guyer, Cheryl A et al. (2003) Ligand- and kinase activity-independent cell survival mediated by the epidermal growth factor receptor expressed in 32D cells. Exp Cell Res 282:121-31
Zhen, Yuejun; Caprioli, Richard M; Staros, James V (2003) Characterization of glycosylation sites of the epidermal growth factor receptor. Biochemistry 42:5478-92
Stein, R A; Wilkinson, J C; Guyer, C A et al. (2001) An analytical approach to the measurement of equilibrium binding constants: application to EGF binding to EGF receptors in intact cells measured by flow cytometry. Biochemistry 40:6142-54
Ewald, J A; Coker, K J; Price, J O et al. (2001) Stimulation of mitogenic pathways through kinase-impaired mutants of the epidermal growth factor receptor. Exp Cell Res 268:262-73
Stein, R A; Staros, J V (2000) Evolutionary analysis of the ErbB receptor and ligand families. J Mol Evol 50:397-412
Woltjer, R L; Staros, J V (1997) Effects of sulfhydryl modification reagents on the kinase activity of the epidermal growth factor receptor. Biochemistry 36:9911-6
Summerfield, A E; Hudnall, A K; Lukas, T J et al. (1996) Identification of residues of the epidermal growth factor receptor proximal to residue 45 of bound epidermal growth factor. J Biol Chem 271:19656-9
Tong, K; Guyer, C A; Staros, J V (1996) Steric constraints in the recognition of peptide substrates for the epidermal growth factor receptor kinase. Int J Pept Protein Res 47:219-26
Stein, R A; Staros, J V (1996) Thermal inactivation of the protein tyrosine kinase of the epidermal growth factor receptor. Biochemistry 35:2878-84
Coker, K J; Staros, J V; Guyer, C A (1994) A kinase-negative epidermal growth factor receptor that retains the capacity to stimulate DNA synthesis. Proc Natl Acad Sci U S A 91:6967-71

Showing the most recent 10 out of 18 publications