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

Gui, Junhong, Liu, Boyi, Cao, Guan, Lipchik, Andrew M., Perez, Minervo, Dekan, Zoltan, Mobli, Mehdi, Daly, Norelle L., Alewood, Paul F., Parker, Laurie L., King, Glenn F., Zhou, Yufeng, Jordt, Sven-Eric, and Nitabach, Michael N. (2014) A tarantula-venom peptide antagonizes the TRPA1 nociceptor ion channel by binding to the S1-S4 gating domain. Current Biology, 24 (5). pp. 473-483.

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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.

Item ID: 32910
Item Type: Article (Research - C1)
ISSN: 1879-0445
Funders: National Institutes of Health (NIH), Australian Research Council (ARC)
Projects and Grants: NIH grant R01NS055035, NIH grant R01NS056443, NIH grant R21NS058330, NIH grant R01GM098931, NIH grant R01ES015056, NIH grant U01ES015674, ARC DP1095729
Date Deposited: 30 Apr 2014 09:40
FoR Codes: 11 MEDICAL AND HEALTH SCIENCES > 1101 Medical Biochemistry and Metabolomics > 110106 Medical Biochemistry: Proteins and Peptides (incl Medical Proteomics) @ 100%
SEO Codes: 97 EXPANDING KNOWLEDGE > 970106 Expanding Knowledge in the Biological Sciences @ 100%
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