title: CRMP2 protein SUMOylation modulates NaV1.7 channel trafficking.
abstract: Voltage-gated sodium channel (NaV) trafficking is incompletely understood. Post-translational modifications of NaVs and/or auxiliary subunits and protein-protein interactions have been posited as NaV-trafficking mechanisms. Here, we tested if modification of the axonal collapsin response mediator protein 2 (CRMP2) by a small ubiquitin-like modifier (SUMO) could affect NaV trafficking; CRMP2 alters the extent of NaV slow inactivation conferred by the anti-epileptic (R)-lacosamide, implying NaV-CRMP2 functional coupling. Expression of a CRMP2 SUMOylation-incompetent mutant (CRMP2-K374A) in neuronal model catecholamine A differentiated (CAD) cells did not alter lacosamide-induced NaV slow inactivation compared with CAD cells expressing wild type CRMP2. Like wild type CRMP2, CRMP2-K374A expressed robustly in CAD cells. Neurite outgrowth, a canonical CRMP2 function, was moderately reduced by the mutation but was still significantly higher than enhanced GFP-transfected cortical neurons. Notably, huwentoxin-IV-sensitive NaV1.7 currents, which predominate in CAD cells, were significantly reduced in CAD cells expressing CRMP2-K374A. Increasing deSUMOylation with sentrin/SUMO-specific protease SENP1 or SENP2 in wild type CRMP2-expressing CAD cells decreased NaV1.7 currents. Consistent with a reduction in current density, biotinylation revealed a significant reduction in surface NaV1.7 levels in CAD cells expressing CRMP2-K374A; surface NaV1.7 expression was also decreased by SENP1 + SENP2 overexpression. Currents in HEK293 cells stably expressing NaV1.7 were reduced by CRMP2-K374A in a manner dependent on the E2-conjugating enzyme Ubc9. No decrement in current density was observed in HEK293 cells co-expressing CRMP2-K374A and NaV1.1 or NaV1.3. Diminution of sodium currents, largely NaV1.7, was recapitulated in sensory neurons expressing CRMP2-K374A. Our study elucidates a novel regulatory mechanism that utilizes CRMP2 SUMOylation to choreograph NaV1.7 trafficking.
authors.affiliation: Paul and Carole Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, Indiana 46202, USA.
authors.forename: Erik T
authors.initials: ET
authors.lastname: Dustrude
authors.forename: Sarah M
authors.initials: SM
authors.lastname: Wilson
authors.forename: Weina
authors.initials: W
authors.lastname: Ju
authors.forename: Yucheng
authors.initials: Y
authors.lastname: Xiao
authors.forename: Rajesh
authors.initials: R
authors.lastname: Khanna
mesh_terms: D019943:Amino Acid Substitution; D000818:Animals; D002395:Catecholamines / Q000494:pharmacology; D002454:Cell Differentiation / Q000187:drug effects / Q000502:physiology; D003546:Cysteine Endopeptidases / Q000235:genetics / Q000378:metabolism; D010450:Endopeptidases / Q000235:genetics / Q000378:metabolism; D057809:HEK293 Cells; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism*; D009097:Multienzyme Complexes / Q000235:genetics / Q000378:metabolism; D020125:Mutation, Missense; D062550:NAV1.1 Voltage-Gated Sodium Channel / Q000235:genetics / Q000378:metabolism; D062552:NAV1.3 Voltage-Gated Sodium Channel / Q000235:genetics / Q000378:metabolism; D062556:NAV1.7 Voltage-Gated Sodium Channel / Q000235:genetics / Q000378:metabolism*; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*; D021381:Protein Transport / Q000187:drug effects / Q000502:physiology; D025842:SUMO-1 Protein / Q000235:genetics / Q000378:metabolism; D011984:Sensory Receptor Cells / Q000166:cytology / Q000378:metabolism*; D015222:Sodium Channels / Q000235:genetics / Q000378:metabolism; D058207:Sumoylation / Q000187:drug effects / Q000502:physiology*; D044763:Ubiquitin-Conjugating Enzymes / Q000235:genetics / Q000378:metabolism; D000098843:Ubiquitin-Conjugating Enzyme UBC9
chemical_list: D002395:Catecholamines; D036341:Intercellular Signaling Peptides and Proteins; D009097:Multienzyme Complexes; D062550:NAV1.1 Voltage-Gated Sodium Channel; D062552:NAV1.3 Voltage-Gated Sodium Channel; D062556:NAV1.7 Voltage-Gated Sodium Channel; D009419:Nerve Tissue Proteins; C568242:SCN1A protein, human; C424715:SCN3A protein, human; C486866:SCN9A protein, human; D025842:SUMO-1 Protein; C568249:Scn1a protein, mouse; C515216:Scn3a protein, mouse; C503479:Scn9a protein, mouse; D015222:Sodium Channels; C095114:collapsin response mediator protein-2; D044763:Ubiquitin-Conjugating Enzymes; D010450:Endopeptidases; C404512:SENP1 protein, human; D003546:Cysteine Endopeptidases; C501833:SENP2 protein, human; C501974:Senp1 protein, mouse; C439066:Senp2 protein, mouse; D000098843:Ubiquitin-Conjugating Enzyme UBC9
keywords: CRMP2; NaV1.1; NaV1.7; Patch Clamp Electrophysiology; Post-translational Modification; Signaling; Sodium Channels; Sumoylation; Trafficking