Single-molecule investigation of nanoscale conformations in human epidermal growth factor receptors
Membrane receptors control fundamental cellular processes ranging from gene expression to apoptosis. Nearly 30% of the human genome encodes membrane proteins, and about 60% of known drugs target the membrane proteins. Mechanistic understanding of membrane receptors and their structural re-organization upon ligand (and drug) binding leading to a variety of cellular processes has both scientific and industrial significance.
In this talk, I will discuss the signal transduction mechanism across full-length human epidermal growth factor receptor (EGFR) which is a major target of anti-cancer drugs. We employ cell-free expression to isolate functional monomeric EGFR within a membrane nanodisc, a lipid bilayer encircled by a belting protein. Using a multidisciplinary approach involving single-molecule Förster resonance energy transfer and mutagenesis, we identify intracellular conformations of full-length EGFR upon extracellular ligand and drug binding. I will further talk about the impact of phosphorylation on the conformations of the intrinsically disordered carboxyl-terminus domain of EGFR. These findings have implications in the formation of signaling complexes and in protein biophysics, in general.
Laser Biomedical Research Center, Massachusetts Institute of Technology, USA