title: Depolarization recruits DCC to the plasma membrane of embryonic cortical neurons and enhances axon extension in response to netrin-1.
abstract: The netrin-1 receptor Deleted in Colorectal Cancer (DCC) is required for the formation of major axonal projections by embryonic cortical neurons, including the corpus callosum, hippocampal commissure, and cortico-thalamic tracts. The presentation of DCC by axonal growth cones is tightly regulated, but the mechanisms regulating DCC trafficking within neurons are not well understood. Here, we investigated the mechanisms regulating DCC recruitment to the plasma membrane of embryonic cortical neurons. In embryonic spinal commissural neurons, protein kinase A (PKA) activation recruits DCC to the plasma membrane and enhances axon chemoattraction to netrin-1. We demonstrate that PKA activation similarly recruits DCC and increases embryonic cortical neuron axon extension, which, like spinal commissural neurons, respond to netrin-1 as a chemoattractant. We then determined if depolarization might recruit DCC to the plasma membrane. Neither netrin-1 induced axon extension, nor levels of plasma membrane DCC, were altered by depolarizing embryonic spinal commissural neurons with elevated levels of KCl. In contrast, depolarizing embryonic cortical neurons increased the amount of plasma membrane DCC, including at the growth cone, and increased axon outgrowth evoked by netrin-1. Inhibition of PKA, phosphatidylinositol-3-kinase, protein kinase C, or exocytosis blocked the depolarization-induced recruitment of DCC and suppressed axon outgrowth. Inhibiting protein synthesis did not affect DCC recruitment, nor were the distributions of trkB or neural cell adhesion molecule (NCAM) influenced by depolarization, consistent with selective mobilization of DCC. These findings identify a role for membrane depolarization modulating the response of axons to netrin-1 by regulating DCC recruitment to the plasma membrane.
authors.affiliation: Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada.
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Bouchard
authors.forename: Katherine E
authors.initials: KE
authors.lastname: Horn
authors.forename: Thomas
authors.initials: T
authors.lastname: Stroh
authors.forename: Timothy E
authors.initials: TE
authors.lastname: Kennedy
mesh_terms: D000818:Animals; D001369:Axons / Q000187:drug effects* / Q000502:physiology / Q000528:radiation effects; D050882:CREB-Binding Protein / Q000378:metabolism; D002118:Calcium / Q000378:metabolism; D002462:Cell Membrane / Q000187:drug effects* / Q000378:metabolism / Q000528:radiation effects; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000166:cytology* / Q000187:drug effects; D005576:Colforsin / Q000494:pharmacology; D000242:Cyclic AMP / Q000378:metabolism; D000075389:DCC Receptor; D004558:Electric Stimulation / Q000379:methods; D004622:Embryo, Mammalian; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D051379:Mice; D009414:Nerve Growth Factors / Q000187:drug effects*; D000075388:Netrin-1; D019006:Neural Cell Adhesion Molecules / Q000378:metabolism; D009474:Neurons / Q000187:drug effects / Q000648:ultrastructure*; D009924:Organ Culture Techniques; D011189:Potassium Chloride / Q000494:pharmacology; D021381:Protein Transport / Q000187:drug effects / Q000502:physiology; D051381:Rats; D020813:Receptor, trkB / Q000378:metabolism; D011956:Receptors, Cell Surface / Q000378:metabolism*; D025521:Tumor Suppressor Proteins / Q000187:drug effects* / Q000378:metabolism*; D050988:Vesicle-Associated Membrane Protein 2 / Q000378:metabolism
chemical_list: D000075389:DCC Receptor; C501910:Dcc protein, mouse; D004791:Enzyme Inhibitors; D009414:Nerve Growth Factors; D019006:Neural Cell Adhesion Molecules; C000617353:Ntn1 protein, mouse; C000617354:Ntn1 protein, rat; D011956:Receptors, Cell Surface; D025521:Tumor Suppressor Proteins; D050988:Vesicle-Associated Membrane Protein 2; D000075388:Netrin-1; D005576:Colforsin; D011189:Potassium Chloride; D000242:Cyclic AMP; D050882:CREB-Binding Protein; D020813:Receptor, trkB; D002118:Calcium