A detailed analysis of the biochemical mechanisms involved in cellular growth and differentiation is crucial to our understanding of the molecular events surrounding normal growth and development, as well as those underlying carcinogenesis. The epidermal growth factor (EGF) receptor is an EGF-responsive protein-tyrosine kinase that undergoes rapid ligand-induced self- phosphorylation on three tyrosine residues (Tyrs 1173, 1148, 1068) located in the extreme carboxy-terminal region of the molecule. The EGF receptor exhibits extensive homology with certain retroviral transforming proteins (also self-phosphorylating tyrosine kinases, e.g. erb B and src) and its overexpression in various human tumors suggests that it plays a critical role in cell proliferation and transformation. This proposal is designed to examine EGF receptor regulation by phosphorylation, with an emphasis on self-phosphorylation. Specifically, it is anticipated that the proposed research plan will elucidate the following: 1) The biochemical properties and regulation by self-phosphorylation of EGF receptor protein-tyrosine kinase and ligand binding activities, 2) the effect of ligand-induced EGF receptor self- phosphorylation on biological events including intracellular tyrosine phosphorylation, DNA synthesis, Ca++ uptake and cell division, and 3) identification and characterization of additional EGF receptor sites of tyrosine and serine/threonine phosphorylation and an initial analysis of their effect on receptor function. This work will use both normal human EGF receptors and available site-directed mutant receptors wherein specific sites of tyrosine self-phosphorylation have been altered to phenylalanine residues (i.e. Tyr 1173 alone, Tyrs 1173 plus 1068, Tyrs 1173, 1068 and 1148, and a mutant wherein these tyrosine residues have been deleted entirely). These studies involve the use and development of methods for kinetic analyses, protein isolation and structural characterization, cell culture and the hormonal control of cellular processes. The knowledge gained from these studies is expected to more rigorously establish the mechanisms by which self-phosphorylation can modulate EGF receptor function and should also prove valuable in understanding possible control mechanisms for other hormone receptors/enzymes that appear regulated by self-phosphorylation and which are important in normal and abnormal cellular metabolism and development.

National Institute of Health (NIH)
National Cancer Institute (NCI)
Research Project (R01)
Project #
Application #
Study Section
Cellular Biology and Physiology Subcommittee 1 (CBY)
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
University of Wisconsin Madison
Schools of Medicine
United States
Zip Code
Watters, Jyoti J; Sommer, Julie A; Pfeiffer, Zachary A et al. (2002) A differential role for the mitogen-activated protein kinases in lipopolysaccharide signaling: the MEK/ERK pathway is not essential for nitric oxide and interleukin 1beta production. J Biol Chem 277:9077-87
Denlinger, L C; Garis, K A; Sommer, J A et al. (1998) Nuclear translocation of NF-kappaB in lipopolysaccharide-treated macrophages fails to correspond to endotoxicity: evidence suggesting a requirement for a gamma interferon-like signal. Infect Immun 66:1638-47
Wiepz, G J; Houtman, J C; Cha, D et al. (1997) Growth hormone attenuation of epidermal growth factor-induced mitogenesis. J Cell Physiol 173:44-53
Denlinger, L C; Fisette, P L; Garis, K A et al. (1996) Regulation of inducible nitric oxide synthase expression by macrophage purinoreceptors and calcium. J Biol Chem 271:337-42
Lin, M L; Bertics, P J (1995) Laminin responsiveness is associated with changes in fibroblast morphology, motility, and anchorage-independent growth: cell system for examining the interaction between laminin and EGF signaling pathways. J Cell Physiol 164:593-604
Proctor, R A; Denlinger, L C; Leventhal, P S et al. (1994) Protection of mice from endotoxic death by 2-methylthio-ATP. Proc Natl Acad Sci U S A 91:6017-20
Duello, T M; Bertics, P J; Fulgham, D L et al. (1994) Localization of epidermal growth factor receptors in first- and third-trimester human placentas. J Histochem Cytochem 42:907-15
Gronowski, A M; Bertics, P J (1993) Evidence for the potentiation of epidermal growth factor receptor tyrosine kinase activity by association with the detergent-insoluble cellular cytoskeleton: analysis of intact and carboxy-terminally truncated receptors. Endocrinology 133:2838-46
Bates, M E; Bertics, P J; Calhoun, W J et al. (1993) Increased protein kinase C activity in low density eosinophils. J Immunol 150:4486-93
Leventhal, P S; Bertics, P J (1993) Activation of protein kinase C by selective binding of arginine-rich polypeptides. J Biol Chem 268:13906-13

Showing the most recent 10 out of 15 publications