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J Gen Physiol. 2018 Nov 5;150(11):1554-1566. doi: 10.1085/jgp.201812124. Epub 2018 Oct 17.

A hypothetical molecular mechanism for TRPV1 activation that invokes rotation of an S6 asparagine.

Author information

1
Institute for Computational Molecular Science, Temple University, Philadelphia, PA.
2
Department of Pharmacology, Physiology and Neuroscience, Rutgers-New Jersey Medical School, Newark, NJ.
3
Institute for Computational Molecular Science, Temple University, Philadelphia, PA vincenzo.carnevale@temple.edu.

Abstract

The transient receptor potential channel vanilloid type 1 (TRPV1) is activated by a variety of endogenous and exogenous stimuli and is involved in nociception and body temperature regulation. Although the structure of TRPV1 has been experimentally determined in both the closed and open states, very little is known about its activation mechanism. In particular, the conformational changes that occur in the pore domain and result in ionic conduction have not yet been identified. Here we suggest a hypothetical molecular mechanism for TRPV1 activation, which involves rotation of a conserved asparagine in S6 from a position facing the S4-S5 linker toward the pore. This rotation is associated with hydration of the pore and dehydration of the four peripheral cavities located between each S6 and S4-S5 linker. In light of our hypothesis, we perform bioinformatics analyses of TRP and other evolutionary related ion channels, evaluate newly available structures, and reexamine previously reported water accessibility and mutagenesis experiments. These analyses provide several independent lines of evidence to support our hypothesis. Finally, we show that our proposed molecular mechanism is compatible with the prevailing theory that the selectivity filter acts as a secondary gate in TRPV1.

PMID:
30333107
PMCID:
PMC6219692
[Available on 2019-05-05]
DOI:
10.1085/jgp.201812124

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