Molecular architecture and subunit organization of TRPA1 ion channel revealed by electron microscopy

J Biol Chem. 2011 Nov 4;286(44):38168-38176. doi: 10.1074/jbc.M111.288993. Epub 2011 Sep 9.

Abstract

Transient receptor potential ankyrin 1 (TRPA1) is a non-selective ion channel, which is expressed in nociceptor sensory neurons and transduces chemical, inflammatory, and neuropathic pain signals. Numerous non-reactive compounds and electrophilic compounds, such as endogenous inflammatory mediators and exogenous pungent chemicals, can activate TRPA1. Here we report a 16-Å resolution structure of purified, functional, amphipol-stabilized TRPA1 analyzed by single-particle EM. Molecular models of the N and C termini of the channel were generated using the I-TASSER protein structure prediction server and docked into the EM density to provide insight into the TRPA1 subunit organization. This structural analysis suggests a location for critical N-terminal cysteine residues involved in electrophilic activation at the interface between neighboring subunits. Our results indicate that covalent modifications within this pocket may alter interactions between subunits and promote conformational changes that lead to channel activation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Calcium / chemistry
  • Chromatography, Gel
  • Circular Dichroism
  • Inflammation
  • Ligands
  • Mice
  • Microscopy, Electron / methods
  • Models, Molecular
  • Molecular Conformation
  • Protein Conformation
  • Protein Structure, Tertiary
  • Saccharomyces cerevisiae / metabolism
  • Structure-Activity Relationship
  • TRPA1 Cation Channel
  • Transient Receptor Potential Channels / metabolism
  • Transient Receptor Potential Channels / ultrastructure*

Substances

  • Ligands
  • TRPA1 Cation Channel
  • Transient Receptor Potential Channels
  • Trpa1 protein, mouse
  • Calcium