Fig. 4: Citronellal activates TRPV3 by binding to the vanilloid site.

a Cryo-EM reconstruction of the full-length wild-type human TRPV3 in ligand-free (TRPV3_Apo). The four subunits of a tetrameric channel protein are colored in four colors (blue, purple, salmon, green) with lipids densities (gray) shown. Close-up views of the vanilloid site in cryo-EM density map is shown in the box. In the TRPV3_Apo map (a), a phosphatidylcholine (PC) lipid (red) occupies the vanilloid site of TRPV3. b Cryo-EM density of POPC (red surface). c Cryo-EM reconstruction of hTRPV3 bound to citronellal (TRPV3_Citronellal). In the TRPV3_Citronellal map (c), citronellal (orange) is nested in the same pocket. d Chemical structure and cryo-EM density of citronellal (orange surface). e The overall structure of a TRPV3_Citronellal tetramer. One chain is shown in blue cartoon and transparent surface, while the remaining three chains are shown as surface representations. f Expanded views of the citronellal binding pocket. The two adjacent chains are shown in dark blue and blue, respectively. The EM density of citronellal is represented by an orange transparent area. g A whole-cell recording of the hTRPV3-L664S mutant. The cell was exposed to different concentrations of citronellal, as indicated. Holding potential was −60 mV. Concentration–response curves of citronellal for activation of hTRPV3 mutants following full sensitization. Solid line indicates fits to the Hill equation with EC₅₀ = 5.78 ± 0.72 mM, n_H = 3.76 ± 1.39 for WT (n = 7 cells); EC₅₀ = 6.25 ± 0.57 mM, n_H = 3.61 ± 0.84 for S576A (n = 7 cells); and EC₅₀ = 5.08 ± 0.36 mM, n_H = 3.81 ± 0.95 for L563S (n = 6 cells). Error bars represent SEM.