Synergistic integration of Netrin and ephrin axon guidance signals by spinal motor neurons

• DOI: 10.7554/elife.10841
• Publication Date: 2015-12-03T12:58:45Z
• Authors: Sebastian Poliak; Daniel Morales; Louis-Philippe Cr...; Dayana Krawchuk; Elena Palmesino; Susan Morton; Jean-François Clo...; Frederic Charron; Matthew B Dalva; Susan L Ackerman; Tzu-Jen Kao; Artur Kania
• Keywords: 0301 basic medicine; QH301-705.5; Receptor, EphB2; Science; Growth Cones; synergy; Ephrin-B2; Receptors, Nerve Growth Factor; Mice; 03 medical and health sciences; motor neurons; Animals; Nerve Growth Factors; Biology (General); Motor Neurons; axon guidance; Tumor Suppressor Proteins; Q; R; Netrin-1; ephrin; Developmental Biology and Stem Cells; Netrin; Medicine; Netrin Receptors; Signal Transduction

During neural circuit assembly, axonal growth cones are exposed to multiple guidance signals at trajectory choice points. While axonal responses to individual guidance cues have been extensively studied, less is known about responses to combination of signals and underlying molecular mechanisms. Here, we studied the convergence of signals directing trajectory selection of spinal motor axons entering the limb. We first demonstrate that Netrin-1 attracts and repels distinct motor axon populations, according to their expression of Netrin receptors. Quantitative in vitro assays demonstrate that motor axons synergistically integrate both attractive or repulsive Netrin-1 signals together with repulsive ephrin signals. Our investigations of the mechanism of ephrin-B2 and Netrin-1 integration demonstrate that the Netrin receptor Unc5c and the ephrin receptor EphB2 can form a complex in a ligand-dependent manner and that Netrin–ephrin synergistic growth cones responses involve the potentiation of Src family kinase signaling, a common effector of both pathways.