Figure 6: Ca²⁺/CaM effector sites on TRPA1 mediating CDP and CDI.

(A) Representative Ca²⁺-induced potentiation (top panels) and desensitization current traces (bottom panels) of different TRPA1 mutants. For potentiation, TRPA1 currents were induced by carvacrol (CV, 50 μM; 100 μM for W996E). For desensitization, 1 mM AITC (60 s) were applied. Blunted desensitization of the W996E, V1008E and P1010E mutants was rescued by overexpressing CaM (pink). (B) Summary of potentiation fold and time constant (τ) of desensitization of TRPA1 mutants from experiments similar to those in (A). All data are mean ± SEM. NS, not significant; *P < 0.05; **P < 0.01; ***P < 0.001 compared with wild type (WT) TRPA1 (n = 5–25 each). (C) Summary of rescue of blunted desensitization of TRPA1 mutants by CaM. The number of experiments is shown above each bar. Data are mean ± SEM. ***P < 0.001. (D) Co-immunoprecipitation (IP) of HA-CaM with TRPA1-V5 mutants in 2 mM Ca²⁺. TRPV1 mutants were first purified using Ni-NTA beads, and equal amount of different total TRPA1 mutants was used for Co-IP (bottom blot). (E) Summary of relative binding of different TRPA1 mutants to CaM normalized by total input proteins from experiments similar to those in (D). All error bars are mean ± SEM. *P < 0.05; ***P < 0.001 (n = 3).