Residues in the pore region of Drosophila transient receptor potential A1 dictate sensitivity to thermal stimuli
Article first published online: 5 DEC 2012
© 2012 The Authors. The Journal of Physiology © 2012 The Physiological Society
The Journal of Physiology
Volume 591, Issue 1, pages 185–201, January 2013
How to Cite
Wang, H., Schupp, M., Zurborg, S. and Heppenstall, P. A. (2013), Residues in the pore region of Drosophila transient receptor potential A1 dictate sensitivity to thermal stimuli. The Journal of Physiology, 591: 185–201. doi: 10.1113/jphysiol.2012.242842
- Issue published online: 7 JAN 2013
- Article first published online: 5 DEC 2012
- Accepted manuscript online: 5 OCT 2012 08:09PM EST
- (Resubmitted 10 August 2012; accepted 25 September 2012; first published online 1 October 2012)
- • Transient receptor potential (TRP) A ion channels are evolutionarily conserved and play a fundamental role in thermal, chemical and mechanical transduction.
- • In this study, we characterized Drosophila TRPA1 as a non-selective cation channel that can be activated by heat, voltage and chemicals.
- • By constructing the chimeric channel between Drosophila TRPA1 and its cold-sensitive human orthologue, we identified key residues in the transmembrane domain that confer heat sensitivity.
- • Perturbation of the putative voltage-sensing module increased the threshold for heat activation.
- • Single channel recordings revealed the reaction schemes of wild-type and mutant channels.
Abstract The capacity to sense temperature is essential for the survival of all animals. At the molecular level, ion channels belonging to the transient receptor potential (TRP) family of channels function as temperature sensors in animals across several phyla. TRP channels are opened directly by changes in temperature and show pronounced sensitivity at their activation range. To determine how temperature activates these channels, we analysed channels belonging to the TRPA family, which detect heat in insects and cold in mammals. By constructing chimeric proteins consisting of human and Drosophila TRPA1 channels, we mapped regions that regulate thermal activation and identified residues in the pore helix that invert temperature sensitivity of TRPA1. From analysis of individual channels we defined the gating reaction of Drosophila TRPA1 and determined how mutagenesis alters the energy landscape for channel opening. Our results reveal specific molecular requirements for thermal activation of TRPA1 and provide mechanistic insight into this process.