EPH receptor tyrosine kinases phosphorylate the PAR-3 scaffold protein to modulate downstream signaling networks
Sara L. Banerjee, Frédéric Lessard, François Chartier, Kévin Jacquet, Ana I. Osornio-Hernandez, Valentine Teyssier, Karim Ghani, Noémie Lavoie, Josée N. Lavoie, Manuel Caruso, Patrick Laprise, Sabine Elowe, Jean‐Philippe Lambert, Nicolas Bisson
Abstract
EPH receptors (EPHRs) constitute the largest family among receptor tyrosine kinases in humans. They are mainly involved in short-range cell-cell communication events that regulate cell adhesion, migration, and boundary formation. However, the molecular mechanisms by which EPHRs control these processes are less understood. To address this, we unravel EPHR-associated complexes under native conditions using mass-spectrometry-based BioID proximity labeling. We obtain a composite proximity network from EPHA4, -B2, -B3, and -B4 that comprises 395 proteins, most of which were not previously linked to EPHRs. We examine the contribution of several BioID-identified candidates via loss-of-function in an EPHR-dependent cell-segregation assay. We find that the signaling scaffold PAR-3 is required for cell sorting and that EPHRs directly phosphorylate PAR-3. We also delineate a signaling complex involving the C-terminal SRC kinase (CSK), whose recruitment to PAR-3 is dependent on EPHR signals. Our work describes signaling networks by which EPHRs regulate cellular phenotypes.