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Electrophile-Induced Conformational Switch of the Human TRPA1 Ion Channel Detected by Mass Spectrometry

Moparthi, Lavanya LU ; Kjellström, Sven LU ; Kjellbom, Per LU ; Filipovic, Milos R ; Zygmunt, Peter M LU and Johanson, Urban LU (2020) In International Journal of Molecular Sciences 21(18).
Abstract

The human Transient Receptor Potential A1 (hTRPA1) ion channel, also known as the wasabi receptor, acts as a biosensor of various potentially harmful stimuli. It is activated by a wide range of chemicals, including the electrophilic compound N-methylmaleimide (NMM), but the mechanism of activation is not fully understood. Here, we used mass spectrometry to map and quantify the covalent labeling in hTRPA1 at three different concentrations of NMM. A functional truncated version of hTRPA1 (Δ1-688 hTRPA1), lacking the large N-terminal ankyrin repeat domain (ARD), was also assessed in the same way. In the full length hTRPA1, the labeling of different cysteines ranged from nil up to 95% already at the lowest concentration of NMM, suggesting... (More)

The human Transient Receptor Potential A1 (hTRPA1) ion channel, also known as the wasabi receptor, acts as a biosensor of various potentially harmful stimuli. It is activated by a wide range of chemicals, including the electrophilic compound N-methylmaleimide (NMM), but the mechanism of activation is not fully understood. Here, we used mass spectrometry to map and quantify the covalent labeling in hTRPA1 at three different concentrations of NMM. A functional truncated version of hTRPA1 (Δ1-688 hTRPA1), lacking the large N-terminal ankyrin repeat domain (ARD), was also assessed in the same way. In the full length hTRPA1, the labeling of different cysteines ranged from nil up to 95% already at the lowest concentration of NMM, suggesting large differences in reactivity of the thiols. Most important, the labeling of some cysteine residues increased while others decreased with the concentration of NMM, both in the full length and the truncated protein. These findings indicate a conformational switch of the proteins, possibly associated with activation or desensitization of the ion channel. In addition, several lysines in the transmembrane domain and the proximal N-terminal region were labeled by NMM, raising the possibility that lysines are also key targets for electrophilic activation of hTRPA1.

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type
Contribution to journal
publication status
published
subject
in
International Journal of Molecular Sciences
volume
21
issue
18
article number
6667
publisher
MDPI AG
external identifiers
  • pmid:32933054
  • scopus:85090639096
ISSN
1422-0067
DOI
10.3390/ijms21186667
language
English
LU publication?
yes
id
2e30abae-a4e0-47c0-976b-940e15fd348f
date added to LUP
2020-09-23 12:45:16
date last changed
2020-09-30 06:44:21
@article{2e30abae-a4e0-47c0-976b-940e15fd348f,
  abstract     = {<p>The human Transient Receptor Potential A1 (hTRPA1) ion channel, also known as the wasabi receptor, acts as a biosensor of various potentially harmful stimuli. It is activated by a wide range of chemicals, including the electrophilic compound N-methylmaleimide (NMM), but the mechanism of activation is not fully understood. Here, we used mass spectrometry to map and quantify the covalent labeling in hTRPA1 at three different concentrations of NMM. A functional truncated version of hTRPA1 (Δ1-688 hTRPA1), lacking the large N-terminal ankyrin repeat domain (ARD), was also assessed in the same way. In the full length hTRPA1, the labeling of different cysteines ranged from nil up to 95% already at the lowest concentration of NMM, suggesting large differences in reactivity of the thiols. Most important, the labeling of some cysteine residues increased while others decreased with the concentration of NMM, both in the full length and the truncated protein. These findings indicate a conformational switch of the proteins, possibly associated with activation or desensitization of the ion channel. In addition, several lysines in the transmembrane domain and the proximal N-terminal region were labeled by NMM, raising the possibility that lysines are also key targets for electrophilic activation of hTRPA1.</p>},
  author       = {Moparthi, Lavanya and Kjellström, Sven and Kjellbom, Per and Filipovic, Milos R and Zygmunt, Peter M and Johanson, Urban},
  issn         = {1422-0067},
  language     = {eng},
  month        = {09},
  number       = {18},
  publisher    = {MDPI AG},
  series       = {International Journal of Molecular Sciences},
  title        = {Electrophile-Induced Conformational Switch of the Human TRPA1 Ion Channel Detected by Mass Spectrometry},
  url          = {http://dx.doi.org/10.3390/ijms21186667},
  doi          = {10.3390/ijms21186667},
  volume       = {21},
  year         = {2020},
}