title: Molecular architecture and subunit organization of TRPA1 ion channel revealed by electron microscopy.
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.
authors: Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, Ohio 44106.
authors: Teresa L
authors: TL
authors: Cvetkov
authors: Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, Ohio 44106.
authors: Kevin W
authors: KW
authors: Huynh
authors: Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, Ohio 44106.
authors: Matthew R
authors: MR
authors: Cohen
authors: Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, Ohio 44106. Electronic address: vxm102@case.edu.
authors: Vera Y
authors: VY
authors: Moiseenkova-Bell
mesh_terms: D000818:Animals; D002118:Calcium / Q000737:chemistry; D002850:Chromatography, Gel; D002942:Circular Dichroism; D007249:Inflammation; D008024:Ligands; D051379:Mice; D008854:Microscopy, Electron / Q000379:methods; D008958:Models, Molecular; D008968:Molecular Conformation; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D013329:Structure-Activity Relationship; D000074025:TRPA1 Cation Channel; D050051:Transient Receptor Potential Channels / Q000378:metabolism / Q000648:ultrastructure*
chemical_list: D008024:Ligands; D000074025:TRPA1 Cation Channel; D050051:Transient Receptor Potential Channels; C475685:Trpa1 protein, mouse; D002118:Calcium