Date of Award
Doctor of Philosophy (PhD)
The Epidermal Growth Factor Receptor (EGFR) is a member of the receptor tyrosine kinase (RTK) family of human proteins with a critical role in transducing diverse extracellular chemical information to initiate multiple cellular signaling cascade in the cell that are essential for normal cell development. Aberrant activation of this receptor via mutation or overexpression misregulates this flow of information and is implicated in a multiple human carcinoma. Thus, understanding the molecular mechanisms by which chemical information is encoded and decoded in EGFR is imperative both from a basic cell biology and therapeutic standpoint. In this thesis consisting of four chapters, I describe my graduate work studying the structure of a portion of EGFR called the juxtamembrane segment (JM) and investigating its role in modulating and controlling the downstream biology of the receptor. Chapter 1: This chapter provides an introduction, overview and in-depth discussion of the literature pertaining to the critical role of JM in modulating EGFR biology through its manifold functions in kinase activation, allosterically encoding structural changes in the various domains of EGFR, and its interactions with diverse intracellular components. Chapter 2: In this chapter I describe my work utilizing a chemical biology tool called Bipartite Tetracysteine Display to study to the structure of the JM of a constitutively active variant of EGFR, namely EGFRvIII that is implicated in most cases of Glioblastoma Multiforme. Through my studies I illustrate how the assembly of unique structures within the JM segment of this oncogenic receptor supports the constitutive activity of this protein. Chapter 3: In this chapter I describe my work utilizing tools in chemical biology, biochemistry and cell biology to demonstrate that the assembly of discrete coiled coil structures within the JM segment of EGFR is necessary and sufficient for controlling the path of endocytic trafficking of the receptor and its intracellular lifetime. Furthermore, I demonstrate how the assembly of these discrete JM structures also predicts kinase-independent effects of oncogenic EGFR mutations (implicated in Non-Small Cell Lung Cancer) and clinically relevant tyrosine kinase inhibitors that promote efficient, lysosome-based EGFR degradation. Chapter 4: This chapter describes preliminary experiments that were performed on two projects that were initiated in the early and later parts of Ph.D. research. The first project seeks to investigate the role of receptor multimerization on the JM structure of EGFR. The second ongoing project seeks to investigate the effect of JM structure on the interactome of WT and oncogenic EGFR using APEX2-based proximity labeling and mass spectrometry. For both projects, I discuss my rationale, experimental design and preliminary results and provide my thoughts for future directions.
Mozumdar, Deepto, "Investigating the Effect of Allostery on Downstream Biology of the Epidermal Growth Factor Receptor" (2021). Yale Graduate School of Arts and Sciences Dissertations. 382.