Format

Send to

Choose Destination
See comment in PubMed Commons below
Curr Biol. 2014 Mar 3;24(5):473-83. doi: 10.1016/j.cub.2014.01.013. Epub 2014 Feb 13.

A tarantula-venom peptide antagonizes the TRPA1 nociceptor ion channel by binding to the S1-S4 gating domain.

Author information

1
Department of Cellular and Molecular Physiology, Yale School of Medicine, New Haven, CT 06520, USA; Department of Genetics, Yale School of Medicine, New Haven, CT 06520, USA; Program in Cellular Neuroscience, Neurodegeneration, and Repair, Yale School of Medicine, New Haven, CT 06520, USA.
2
Department of Pharmacology, Yale School of Medicine, New Haven, CT 06520, USA.
3
Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, IN 47907, USA.
4
Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia.
5
Centre for Advanced Imaging, The University of Queensland, Brisbane, QLD 4072, Australia.
6
Centre for Biodiscovery and Molecular Development of Therapeutics, Queensland Tropical Health Alliance, James Cook University, Cairns, QLD 4870, Australia.
7
Department of Cellular and Molecular Physiology, Yale School of Medicine, New Haven, CT 06520, USA.
8
Department of Cellular and Molecular Physiology, Yale School of Medicine, New Haven, CT 06520, USA; Department of Genetics, Yale School of Medicine, New Haven, CT 06520, USA; Program in Cellular Neuroscience, Neurodegeneration, and Repair, Yale School of Medicine, New Haven, CT 06520, USA. Electronic address: michael.nitabach@yale.edu.

Abstract

BACKGROUND:

The venoms of predators have been an excellent source of diverse highly specific peptides targeting ion channels. Here we describe the first known peptide antagonist of the nociceptor ion channel transient receptor potential ankyrin 1 (TRPA1).

RESULTS:

We constructed a recombinant cDNA library encoding ∼100 diverse GPI-anchored peptide toxins (t-toxins) derived from spider venoms and screened this library by coexpression in Xenopus oocytes with TRPA1. This screen resulted in identification of protoxin-I (ProTx-I), a 35-residue peptide from the venom of the Peruvian green-velvet tarantula, Thrixopelma pruriens, as the first known high-affinity peptide TRPA1 antagonist. ProTx-I was previously identified as an antagonist of voltage-gated sodium (NaV) channels. We constructed a t-toxin library of ProTx-I alanine-scanning mutants and screened this library against NaV1.2 and TRPA1. This revealed distinct partially overlapping surfaces of ProTx-I by which it binds to these two ion channels. Importantly, this mutagenesis yielded two novel ProTx-I variants that are only active against either TRPA1or NaV1.2. By testing its activity against chimeric channels, we identified the extracellular loops of the TRPA1 S1-S4 gating domain as the ProTx-I binding site.

CONCLUSIONS:

These studies establish our approach, which we term "toxineering," as a generally applicable method for isolation of novel ion channel modifiers and design of ion channel modifiers with altered specificity. They also suggest that ProTx-I will be a valuable pharmacological reagent for addressing biophysical mechanisms of TRPA1 gating and the physiology of TRPA1 function in nociceptors, as well as for potential clinical application in the context of pain and inflammation.

PMID:
24530065
PMCID:
PMC3949122
DOI:
10.1016/j.cub.2014.01.013
[Indexed for MEDLINE]
Free PMC Article
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for Elsevier Science Icon for PubMed Central
    Loading ...
    Support Center