The epidermal growth factor receptor (EGFR) is a critical regulator of normal and oncogenic cell behaviors. The spatiotemporal regulation of EGFR-regulated signaling complexes remains incompletely understood but has important implications for deciphering the full complement of mechanisms through which EGFR can affect cellular phenotypes. Here, we use a computational reaction-diffusion model to explore the ability of EGFR to regulate the intracellular length scale over which signaling protein complexes containing the protein tyrosine phosphatase SHP2, a proto-oncogene, persist distal from EGFR. SHP2 activity is regulated by a structural rearrangement that occurs when its N-terminal SH2 domains are engaged by phosphotyrosines. We show that EGFR activates cytosolic Src family kinases (SFKs) to maintain the association between tyrosine-phosphorylated GAB1 and SHP2 over the full intracellular length scale through repeated cycles of complex dissociation and GAB1 dephosphorylation. A global parameter sensitivity analysis identified protein diffusion, SFK inactivation, SHP2-GAB1 binding, and GAB1 dephosphorylation as the processes that most strongly control the length scale of GAB1-SHP2 complex persistence. An independent model scaling analysis likewise predicted that GAB1-SHP2 complexes persist throughout the cell volume. Proximity ligation assays and immunofluorescence imaging of cultured cells experimentally confirmed that GAB1-SHP2 complexes are distributed throughout cells and exist distal from EGFR in response to EGF. These results suggest that membrane-bound EGFR can regulate SHP2-mediated signaling events over the entire intracellular length scale through the activity of diffusible SFKs. Understanding the extent to which this mechanism takes place for other receptors and downstream complexes has important implications for linking signaling processes to their initiating receptors and for the design of pharmacological approaches to interfere with aberrant receptor signaling.

Reaction-diffusion model predicts the intracellular length scale of GAB1-SHP2 complex persistence in response to EGFR activation

ACS Spring 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.