title: Hierarchical CRMP2 posttranslational modifications control NaV1.7 function.
abstract: Voltage-gated sodium channels are crucial determinants of neuronal excitability and signaling. Trafficking of the voltage-gated sodium channel NaV1.7 is dysregulated in neuropathic pain. We identify a trafficking program for NaV1.7 driven by hierarchical interactions with posttranslationally modified versions of the binding partner collapsin response mediator protein 2 (CRMP2). The binding described between CRMP2 and NaV1.7 was enhanced by conjugation of CRMP2 with small ubiquitin-like modifier (SUMO) and further controlled by the phosphorylation status of CRMP2. We determined that CRMP2 SUMOylation is enhanced by prior phosphorylation by cyclin-dependent kinase 5 and antagonized by Fyn phosphorylation. As a consequence of CRMP2 loss of SUMOylation and binding to NaV1.7, the channel displays decreased membrane localization and current density, and reduces neuronal excitability. Preventing CRMP2 SUMOylation with a SUMO-impaired CRMP2-K374A mutant triggered NaV1.7 internalization in a clathrin-dependent manner involving the E3 ubiquitin ligase Nedd4-2 (neural precursor cell expressed developmentally down-regulated protein 4) and endocytosis adaptor proteins Numb and epidermal growth factor receptor pathway substrate 15. Collectively, our work shows that diverse modifications of CRMP2 cross-talk to control NaV1.7 activity and illustrate a general principle for regulation of NaV1.7.
authors.affiliation: Department of Pharmacology, College of Medicine, University of Arizona, Tucson, AZ 85742.
authors.forename: Erik T
authors.initials: ET
authors.lastname: Dustrude
authors.affiliation: Department of Pharmacology, College of Medicine, University of Arizona, Tucson, AZ 85742.
authors.forename: Aubin
authors.initials: A
authors.lastname: Moutal
authors.affiliation: Department of Pharmacology, College of Medicine, University of Arizona, Tucson, AZ 85742.
authors.forename: Xiaofang
authors.initials: X
authors.lastname: Yang
authors.affiliation: Department of Pharmacology, College of Medicine, University of Arizona, Tucson, AZ 85742.
authors.forename: Yuying
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Department of Pharmacology, College of Medicine, University of Arizona, Tucson, AZ 85742.
authors.forename: May
authors.initials: M
authors.lastname: Khanna
authors.affiliation: Department of Pharmacology, College of Medicine, University of Arizona, Tucson, AZ 85742; rkhanna@email.arizona.edu.|Neuroscience Graduate Interdisciplinary Program, College of Medicine, University of Arizona, Tucson, AZ 85742.
authors.forename: Rajesh
authors.identifier: 0000-0002-9066-2969
authors.initials: R
authors.lastname: Khanna
mesh_terms: D000818:Animals; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism; D004705:Endocytosis; D011992:Endosomes / Q000378:metabolism; D057809:HEK293 Cells; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000502:physiology*; D008297:Male; D062556:NAV1.7 Voltage-Gated Sodium Channel / Q000502:physiology*; D009419:Nerve Tissue Proteins / Q000502:physiology*; D009474:Neurons / Q000378:metabolism; D010146:Pain / Q000235:genetics / Q000378:metabolism; D018408:Patch-Clamp Techniques; D010766:Phosphorylation; D011499:Protein Processing, Post-Translational; D021381:Protein Transport; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D036341:Intercellular Signaling Peptides and Proteins; D062556:NAV1.7 Voltage-Gated Sodium Channel; D009419:Nerve Tissue Proteins; C486866:SCN9A protein, human; C503480:Scn9a protein, rat; C095114:collapsin response mediator protein-2
keywords: CRMP2; NaV1.7 sodium channel; SUMOylation; phosphorylation; trafficking