Dissection of the components for PIP ₂ activation and thermosensation in TRP channels

Phosphatidylinositol 4,5-bisphosphate (PIP 2 ) plays a central role in the activation of several transient receptor potential (TRP) channels. The role of PIP 2 on temperature gating of thermoTRP channels has not been explored in detail, and the process of temperature activation is largely unexplained. In this work, we have exchanged different segments of the C-terminal region between cold-sensitive (TRPM8) and heat-sensitive (TRPV1) channels, trying to understand the role of the segment in PIP 2 and temperature activation. A chimera in which the proximal part of the C-terminal of TRPV1 replaces an equivalent section of TRPM8 C-terminal is activated by PIP 2 and confers the phenotype of heat activation. PIP 2 , but not temperature sensitivity, disappears when positively charged residues contained in the exchanged region are neutralized. Shortening the exchanged segment to a length of 11 aa produces voltage-dependent and temperature-insensitive channels. Our findings suggest the existence of different activation domains for temperature, PIP 2 , and voltage. We provide an interpretation for channel–PIP 2 interaction using a full-atom molecular model of TRPV1 and PIP 2 docking analysis.