The fibroblast growth factor 14·voltage-gated sodium channel complex is a new target of glycogen synthase kinase 3 (GSK3)

J Biol Chem. 2013 Jul 5;288(27):19370-85. doi: 10.1074/jbc.M112.445924. Epub 2013 May 2.

Abstract

The FGF14 protein controls biophysical properties and subcellular distribution of neuronal voltage-gated Na(+) (Nav) channels through direct binding to the channel C terminus. To gain insights into the dynamic regulation of this protein/protein interaction complex, we employed the split luciferase complementation assay to screen a small molecule library of kinase inhibitors against the FGF14·Nav1.6 channel complex and identified inhibitors of GSK3 as hits. Through a combination of a luminescence-based counter-screening, co-immunoprecipitation, patch clamp electrophysiology, and quantitative confocal immunofluorescence, we demonstrate that inhibition of GSK3 reduces the assembly of the FGF14·Nav channel complex, modifies FGF14-dependent regulation of Na(+) currents, and induces dissociation and subcellular redistribution of the native FGF14·Nav channel complex in hippocampal neurons. These results further emphasize the role of FGF14 as a critical component of the Nav channel macromolecular complex, providing evidence for a novel GSK3-dependent signaling pathway that might control excitability through specific protein/protein interactions.

Keywords: Excitability; FGF14; GSK3; Ion Channels; Neurons; Phosphorylation; Protein/Protein Interactions; Sodium Channels.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Enzyme Inhibitors / pharmacology
  • Fibroblast Growth Factors / genetics
  • Fibroblast Growth Factors / metabolism*
  • Glycogen Synthase Kinase 3 / antagonists & inhibitors
  • Glycogen Synthase Kinase 3 / genetics
  • Glycogen Synthase Kinase 3 / metabolism*
  • HEK293 Cells
  • Hippocampus / cytology
  • Hippocampus / metabolism*
  • Humans
  • Mice
  • Mice, Knockout
  • Multiprotein Complexes / genetics
  • Multiprotein Complexes / metabolism*
  • NAV1.6 Voltage-Gated Sodium Channel / genetics
  • NAV1.6 Voltage-Gated Sodium Channel / metabolism*
  • Neurons / cytology
  • Neurons / metabolism*
  • Rats
  • Signal Transduction / drug effects

Substances

  • Enzyme Inhibitors
  • Multiprotein Complexes
  • NAV1.6 Voltage-Gated Sodium Channel
  • SCN8A protein, human
  • Scn8a protein, mouse
  • Scn8a protein, rat
  • fibroblast growth factor 14
  • Fibroblast Growth Factors
  • Glycogen Synthase Kinase 3