RT Journal Article
SR Electronic
T1 G<sub>αq</sub> sensitizes TRPM8 to inhibition by PI(4,5)P<sub>2</sub> depletion upon receptor activation
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 410878
DO 10.1101/410878
A1 Luyu Liu
A1 Yevgen Yudin
A1 Chifei Kang
A1 Natalia Shirokova
A1 Tibor Rohacs
YR 2018
UL http://biorxiv.org/content/early/2018/09/06/410878.abstract
AB Activation of G-protein coupled receptors (GPCRs) was proposed to inhibit the cold and menthol sensitive Transient Receptor Potential Melastatin 8 (TRPM8) channels via direct binding of Gαq to the channel. It is well documented that TRPM8 requires the plasma membrane phospholipid phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2 or PIP2] for activity. It was claimed however that a decrease in cellular levels of this lipid does not contribute to channel inhibition upon receptor activation. Here we show that supplementing the whole cell patch pipette with PI(4,5)P2 reduced inhibition of TRPM8 by activation of Gαq-coupled receptors in mouse dorsal root ganglion (DRG) neurons. Activation of the same receptors induced Phospholipase C (PLC) activation and decreased plasma membrane PI(4,5)P2 levels in these neurons. PI(4,5)P2 also reduced inhibition of TRPM8 by activation of heterologously expressed Gαq-coupled muscarinic M1 receptors. Co-expression of a constitutively active Gαq protein that does not couple to PLC inhibited TRPM8 activity, and in cells expressing this protein decreasing PI(4,5)P2 levels using a voltage sensitive 5’-phosphatase induced a stronger inhibition of TRPM8 activity than in control cells. Our data indicate that PI(4,5)P2 depletion plays an important role in TRPM8 inhibition upon GPCR activation, and Gαq inhibits the channel by reducing its apparent affinity for PI(4,5)P2 and thus sensitizes the channel to inhibition by decreasing PI(4,5)P2 levels.T.R. was supported by NIH grants NS055159 and GM093290. The authors thank Dr. Joshua Berlin for his insightful comments, Dr. David Julius (UCSF) for providing the TRPM8 clone, Dr. David McKemy (University of Southern California) for providing the GFP-TRPM8 mouse line, Dr. Yasushi Okamura (Osaka University, Japan) for providing the ci-VSP and dr-VSP clones, Drs. Nikita Gamper (University of Leeds) and Andrew Tinker (University College London) for providing the tubby-R332H-YFP clone, Dr. Xuming Zhang (Aston University, Birmingham, UK) for providing the 3Gqiq clone, and Linda Zabelka for maintaining the mouse colony.