Engineering Vanilloid-Sensitivity into the TRPV2 Channel

Abstract

Abstract: The TRPV1 channel is a polymodal detector of noxious stimuli, including heat, acidosis, pungent vanilloid compounds and pro-inflammatory lipids. The gating mechanisms of the closely related TRPV2 channel are poorly understood because they are vanilloid-insensitive and only activated by extremely high temperatures above 50 °C. Recent cryo-EM structures of the TRPV1 channel identified a putative vanilloid binding pocket at the interface between S1-S4 domains and the pore domain. Here we use biophysical, biochemical, and electrophysiological approaches to investigate the vanilloid binding site and gating relationships between TRPV1 and TRPV2. Although the S1-S4 domain from TRPV1 can be expressed and purified in isolation of the pore domain, it does not bind vanilloids with high affinity. We identified four non-conserved residues in the vanilloid binding pocket of TRPV1 that when introduced into TRPV2 channels are sufficient to generate high-affinity vanilloid binding and robust channel activation. Taken together, our results support the identification of the vanilloid binding pocket in the TRPV1 structure, and suggest that TRPV1 and TRPV2 channels share common gating mechanisms even though their functional properties are distinct.