Monitoring Conformational Changes in the Receptor Tyrosine Kinase EGFR

Abstract

The receptor tyrosine kinase EGFR is regulated by complex conformational changes, and this conformational control is disturbed in certain types of cancer. Many ligands are known to bind EGFR in its active conformation, thereby preventing ATP from binding. Only a few ligands are known to stabilize EGFR in its inactive conformation, thus providing novel strategies for perturbing EGFR activity. We report a direct binding assay that enables the identification of novel ligands that bind to and stabilize the inactive conformation of EGFR.

Structure Defines Function: Clinically Relevant Mutations in ErbB Kinases

“…27,34 This kinase conformation facilitates binding of inhibitors, such as lapatinib or neratinib, 35 which can be assessed by a direct binding assay utilizing a fluorescent labeled activation loop. 36 The interaction with the activator kinase forces a rearrangement of the receiver kinase, resulting in its active state. The activated conformation exhibits an extended activation loop (blue), stabilized by a short antiparallel β-segment, to allow inward rotation of helix C (green), which creates the interaction surface with the activator kinase.…”

“…This formation allows interaction of the C-terminus of the activator kinase with the N-terminal portion of the receiver kinase. The inactive receiver kinase is characterized by an outward rotated helix αC (Figure A, red), which allows the activation loop (orange) to form a short helical segment next to the helix αC. , This kinase conformation facilitates binding of inhibitors, such as lapatinib or neratinib, which can be assessed by a direct binding assay utilizing a fluorescent labeled activation loop . The interaction with the activator kinase forces a rearrangement of the receiver kinase, resulting in its active state.…”