Mapping of the FGF14:Nav1.6 complex interface reveals FLPK as a functionally active peptide modulating excitability
Aditya K Singh1, Paul A Wadsworth1,2,3, Cynthia M Tapia1,4
1Department of Pharmacology & Toxicology, University of Texas Medical Branch, Galveston, TX, USA.
Physiological Reports
|July 17, 2020
Summary
A novel peptide, FLPK, disrupts the interaction between fibroblast growth factor 14 (FGF14) and Nav1.6 sodium channels. This peptide modulates neuronal excitability by interfering with sodium channel inactivation.
Area of Science:
- Neuroscience
- Molecular Biology
- Biophysics
Background:
- Voltage-gated sodium (Nav) channels are crucial for neuronal excitability.
- Fibroblast growth factor 14 (FGF14) is an accessory protein that modulates Nav1.6 channel function.
- The interaction between FGF14 and the Nav1.6 C-terminal tail influences neuronal intrinsic excitability.
Purpose of the Study:
- To investigate the role of the FGF14 V160 residue in FGF14:Nav1.6 complex formation.
- To evaluate the effect of a peptide (FLPK) targeting this interaction on Nav1.6 channel activity and neuronal firing.
- To explore FLPK as a potential tool for probing Nav channel function and developing modulators.
Main Methods:
- In silico docking to predict peptide-target interactions.
- Split-luciferase assay (LCA) and surface plasmon resonance (SPR) to confirm complex formation.
- Whole-cell patch-clamp electrophysiology in neurons to assess channel activity and firing frequency.
Main Results:
- FLPK peptide was designed to interfere with FGF14:Nav1.6 binding at the V160 hotspot.
- FLPK disrupted the FGF14:Nav1.6 complex and prevented FGF14-dependent Nav1.6 current modulation.
- FLPK increased neuronal firing frequency by inhibiting Nav1.6 inactivation, requiring the FGF14 N-terminal tail.
Conclusions:
- FLPK acts as a molecular probe to dissect FGF14:Nav1.6 interactions and their impact on neuronal excitability.
- The findings highlight the importance of the FGF14 N-terminal tail in regulating Nav1.6 inactivation.
- FLPK serves as a potential scaffold for developing allosteric modulators of Nav channels.
Related Concept Videos
01:30Transducer Mechanism: G Protein–Coupled Receptors
G Protein–Coupled Receptors (GPCRs) are membrane-bound receptors that transiently associate with heterotrimeric G proteins and induce an appropriate response to various stimuli. GPCRs regulate critical physiological pathways and are excellent drug targets for treating diseases such as diabetes, cancer, obesity, depression, or Alzheimer's. Nearly 35% of approved drugs implement their therapeutic effects by selectively interacting with specific GPCRs.
GPCRs are also called heptahelical, 7TM, or...
GPCRs are also called heptahelical, 7TM, or...
01:30Ligand-Gated Ion Channel Receptor: Gating Mechanism
Ligand-gated ion channels are transmembrane proteins that play a vital role in intercellular communication and functions of the nervous system. They allow the influx of ions across the membrane once the neurotransmitter binds, allowing the subsequent transmission of electrical excitation across the neurons. Other ligand-gated ion channels, like the γ-aminobutyric acid (GABA) receptor, permit anions like chloride into the cells on the binding of the GABA molecule. Their entry into the cell...