SummaryThe proto-oncogenic epidermal growth factor receptor (EGFR) is a tyrosine kinase whose sensitivity to growth factors and signal duration determines cellular behavior. We resolve how EGFR's response to epidermal growth factor (EGF) originates from dynamically established recursive interactions with spatially organized protein tyrosine phosphatases (PTPs). Reciprocal genetic PTP perturbations enabled identification of receptor-like PTPRG/J at the plasma membrane and ER-associated PTPN2 as the major EGFR dephosphorylating activities. Imaging spatial-temporal PTP reactivity revealed that vesicular trafficking establishes a spatially distributed negative feedback with PTPN2 that determines signal duration. On the other hand, single-cell dose-response analysis uncovered a reactive oxygen species-mediated toggle switch between autocatalytically activated monomeric EGFR and the tumor suppressor PTPRG that governs EGFR's sensitivity to EGF. Vesicular recycling of monomeric EGFR unifies the interactions with these PTPs on distinct membrane systems, dynamically generating a network architecture that can sense and respond to time-varying growth factor signals.

Spatially-organized interaction dynamics between proto-oncogenic epidermal growth factor receptor (EGFR) and protein tyrosine phosphatases (PTPs) determine EGFR′s phosphorylation response to growth factors and thereby cellular behavior within developing tissues. We show here, that and how the coupling between EGFR and RPTPγ activity leads to migratory signaling responses to very low, physiological growth factor stimuli while suppressing aberrant, spontaneous signaling. Single cell imaging of EGFR phosphorylation and PTP oxidation revealed that RPTPγ fully suppresses spontaneous EGFR phosphorylation, while EGF-induced NADPH-oxidase activity enables promigratory signaling responses at the plasma membrane by H2O2-mediated oxidative inhibition of RPTPγ′s phosphatase activity. The EGF-dependent toggle switch dynamics between interacting EGFR monomers and RPTPγ thereby enables autocatalytically amplified phosphorylation responses to very low, physiological, EGF levels even at sparse receptor expression. This signaling mechanism is distinct from the proliferative signaling stemming from liganded endosomal EGFR complexes at high growth factor concentrations. Accordingly, RPTPγ knock-out results in spontaneous promigratory EGFR signaling but loss of proliferative signaling. We thereby provide evidence of RPTPγ′s suppressor function of oncogenic, promigratory EGFR-signaling from the plasma membrane.

Spatially organized reaction dynamics between proto‐oncogenic epidermal growth factor receptor (EGFR) and protein tyrosine phosphatases determine EGFR phosphorylation dynamics in response to growth factors and thereby cellular behavior within developing tissues. We show that the reaction dynamics of mutual inhibition between RPTPγ phosphatase and autocatalytic ligandless EGFR phosphorylation enable highly sensitive promigratory EGFR signaling responses to subnanomolar EGF levels, when < 5% receptors are occupied by EGF. EGF thereby triggers an autocatalytic phospho‐EGFR reaction by the initial production of small amounts of phospho‐EGFR through transient, asymmetric EGF‐EGFR2 dimers. Single cell RPTPγ oxidation imaging revealed that phospho‐EGFR induces activation of NADPH oxidase, which in turn inhibits RPTPγ‐mediated dephosphorylation of EGFR, tilting the autocatalytic RPTPγ/EGFR toggle switch reaction towards ligandless phosphorylated EGFR. Reversibility of this reaction to EGF is maintained by the constitutive phosphatase activity of endoplasmic reticulum‐associated TCPTP. This RPTPγ/EGFR reaction at the plasma membrane causes promigratory signaling that is separated from proliferative signaling induced by accumulated, liganded, phosphorylated EGF‐EGFR in endosomes. Accordingly, loss of RPTPγ results in constitutive promigratory signaling from phosphorylated EGFR monomers. RPTPγ is thus a suppressor of promigratory oncogenic but not of proliferative EGFR signaling.