title: Sensory neuron proteins interact with the intracellular domains of sodium channel NaV1.8.
abstract: Voltage-gated sodium channels initiate and propagate action potentials in excitable cells. The tetrodotoxin-resistant Na(+) channel (Na(V)1.8/SNS) is expressed in damage-sensing neurons (nociceptors) and plays an important role in pain pathways. Expression of high levels of functional Na(V)1.8 in heterologous cells has proved problematic, even in the presence of known sodium channel accessory beta-subunits. This suggests that other regulatory proteins are required for normal levels of Na(V)1.8 expression. Here we report the use of a yeast two-hybrid system and a rat dorsal root ganglion cDNA library to identify 28 different clones encoding proteins which interact with intracellular domains of Na(V)1.8. Many clones are expressed at high levels in small diameter DRG neurons as judged by in situ hybridization. Interacting proteins include cytoplasmic elements and linker proteins (e.g. beta-actin and moesin), enzymes (e.g. inositol polyphosphate 5-phosphatase and TAO2 thousand and one protein kinase), channels and membrane-associated proteins (voltage-dependent anion channel VDAC3V and tetraspanin), as well as motor proteins (dynein intermediate and light chain) and transcripts encoding previously undescribed proteins. Immunoprecipitation (pull-down) assays confirm that some of the proteins interact with, and may hence regulate, Na(V)1.8 in vivo.
authors.affiliation: Department of Biology, University College London, Gower Street, London WC1E 6BT, UK.
authors.forename: Misbah
authors.initials: M
authors.lastname: Malik-Hall
authors.forename: W-Y Louisa
authors.initials: WY
authors.lastname: Poon
authors.forename: Mark D
authors.initials: MD
authors.lastname: Baker
authors.forename: John N
authors.initials: JN
authors.lastname: Wood
authors.forename: Kenji
authors.initials: K
authors.lastname: Okuse
mesh_terms: D000818:Animals; D002462:Cell Membrane / Q000378:metabolism*; D003600:Cytosol / Q000378:metabolism*; D005727:Ganglia, Spinal / Q000378:metabolism*; D062559:NAV1.8 Voltage-Gated Sodium Channel; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D009475:Neurons, Afferent / Q000378:metabolism*; D009479:Neuropeptides / Q000235:genetics / Q000378:metabolism*; D009619:Nociceptors / Q000378:metabolism; D010146:Pain / Q000235:genetics / Q000378:metabolism; D017434:Protein Structure, Tertiary / Q000235:genetics; D021381:Protein Transport / Q000235:genetics; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D015222:Sodium Channels / Q000235:genetics / Q000378:metabolism*; D020798:Two-Hybrid System Techniques; D050994:Voltage-Dependent Anion Channels
chemical_list: D062559:NAV1.8 Voltage-Gated Sodium Channel; D009419:Nerve Tissue Proteins; D009479:Neuropeptides; D012333:RNA, Messenger; C568319:Scn10a protein, rat; D015222:Sodium Channels; C494770:VDAC3v protein, rat; D050994:Voltage-Dependent Anion Channels