TY - JOUR
T1 - Bimodal voltage dependence of TRPA1
T2 - Mutations of a key pore helix residue reveal strong intrinsic voltage-dependent inactivation
AU - Wan, Xia
AU - Lu, Yungang
AU - Chen, Xueqin
AU - Xiong, Jian
AU - Zhou, Yuanda
AU - Li, Ping
AU - Xia, Bingqing
AU - Li, Min
AU - Zhu, Michael X.
AU - Gao, Zhaobing
N1 - Funding Information:
We thank Drs. Jun Chen, Haoxing Xu, and Feng Qin for helpful discussions of the project. This work was supported by the National Key Basic Research Program of China (2013CB910604), the National Science and Technology Major Project on “Key New Drug Creation and Manufacturing Program” (2013ZX09103001-016), the National Natural Science Foundation of China Grant for Excellent Key Laboratory (81123004), and the Special Research Foundation of Chinese Academy of Sciences (F030304:61327014). The research in MXZ and ML laboratories are supported in part by grants from the US National Institutes of Health, R01DK081654 and U54MH084691, respectively.
PY - 2014/7
Y1 - 2014/7
N2 - Transient receptor potential A1 (TRPA1) is implicated in somatosensory processing and pathological pain sensation. Although not strictly voltage-gated, ionic currents of TRPA1 typically rectify outwardly, indicating channel activation at depolarized membrane potentials. However, some reports also showed TRPA1 inactivation at high positive potentials, implicating voltage-dependent inactivation. Here we report a conserved leucine residue, L906, in the putative pore helix, which strongly impacts the voltage dependency of TRPA1. Mutation of the leucine to cysteine (L906C) converted the channel from outward to inward rectification independent of divalent cations and irrespective to stimulation by allyl isothiocyanate. The mutant, but not the wild-type channel, displayed exclusively voltage-dependent inactivation at positive potentials. The L906C mutation also exhibited reduced sensitivity to inhibition by TRPA1 blockers, HC030031 and ruthenium red. Further mutagenesis of the leucine to all natural amino acids individually revealed that most substitutions at L906 (15/19) resulted in inward rectification, with exceptions of three amino acids that dramatically reduced channel activity and one, methionine, which mimicked the wild-type channel. Our data are plausibly explained by a bimodal gating model involving both voltage-dependent activation and inactivation of TRPA1. We propose that the key pore helix residue, L906, plays an essential role in responding to the voltage-dependent gating.
AB - Transient receptor potential A1 (TRPA1) is implicated in somatosensory processing and pathological pain sensation. Although not strictly voltage-gated, ionic currents of TRPA1 typically rectify outwardly, indicating channel activation at depolarized membrane potentials. However, some reports also showed TRPA1 inactivation at high positive potentials, implicating voltage-dependent inactivation. Here we report a conserved leucine residue, L906, in the putative pore helix, which strongly impacts the voltage dependency of TRPA1. Mutation of the leucine to cysteine (L906C) converted the channel from outward to inward rectification independent of divalent cations and irrespective to stimulation by allyl isothiocyanate. The mutant, but not the wild-type channel, displayed exclusively voltage-dependent inactivation at positive potentials. The L906C mutation also exhibited reduced sensitivity to inhibition by TRPA1 blockers, HC030031 and ruthenium red. Further mutagenesis of the leucine to all natural amino acids individually revealed that most substitutions at L906 (15/19) resulted in inward rectification, with exceptions of three amino acids that dramatically reduced channel activity and one, methionine, which mimicked the wild-type channel. Our data are plausibly explained by a bimodal gating model involving both voltage-dependent activation and inactivation of TRPA1. We propose that the key pore helix residue, L906, plays an essential role in responding to the voltage-dependent gating.
KW - Gating
KW - Pore helix rotation
KW - TRPA1
KW - Voltage dependence
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U2 - 10.1007/s00424-013-1345-6
DO - 10.1007/s00424-013-1345-6
M3 - Article
C2 - 24092046
AN - SCOPUS:84904631967
SN - 0031-6768
VL - 466
SP - 1273
EP - 1287
JO - Pflugers Archiv European Journal of Physiology
JF - Pflugers Archiv European Journal of Physiology
IS - 7
ER -