Figure 3.

Photodynamic activation of TRPA1. Purified human TRPA1 reconstituted into artificial lipid (1,2-diphytanoyl-snglycero-3-phosphocholine: cholesterol was 9:1) bilayers with both the N- and C-terminals facing the cytosol were voltage-clamped at + 60 mV. PPIX (1 μM) was added to the cytosolic side, laser light (405 nm) was applied (at 0.45 mW/mm²). Single channel currents were measured using Patch-a-Patch in symmetrical K⁺ solution (150 mM KCl, 10 mM HEPES) under light illumination alone (Light), protoporphyrin IX alone (PPIX), or PPIX plus light (Light + PPIX) as indicated. Scale bars indicate 2 pA current and 1 s. Only simultaneous presence of light and PPIX (photodynamic action) led to channel opening. From Babes et al. (2016).