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  • Endocannabinoids produced in photoreceptor cells in response to light activate Drosophila TRP channels.

Endocannabinoids produced in photoreceptor cells in response to light activate Drosophila TRP channels.

Science signaling (2022-10-12)
Takaaki Sokabe, Heather B Bradshaw, Makoto Tominaga, Emma Leishman, Avinash Chandel, Craig Montell
ABSTRACT

Drosophila phototransduction is a model for signaling cascades that culminate in the activation of transient receptor potential (TRP) cation channels. TRP and TRPL are the canonical TRP (TRPC) channels that are regulated by light stimulation of rhodopsin and engagement of Gαq and phospholipase Cβ (PLC). Lipid metabolite(s) generated downstream of PLC are essential for the activation of the TRPC channels in photoreceptor cells. We sought to identify the key lipids produced subsequent to PLC stimulation that contribute to channel activation. Here, using genetics, lipid analysis, and Ca2+ imaging, we found that light increased the amount of an abundant endocannabinoid, 2-linoleoyl glycerol (2-LG), in vivo. The increase in 2-LG amounts depended on the PLC and diacylglycerol lipase encoded by norpA and inaE, respectively. This endocannabinoid facilitated TRPC-dependent Ca2+ influx in a heterologous expression system and in dissociated ommatidia from compound eyes. Moreover, 2-LG and mechanical stimulation cooperatively activated TRPC channels in ommatidia. We propose that 2-LG is a physiologically relevant endocannabinoid that activates TRPC channels in photoreceptor cells.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Ruthenium Red, Technical grade
Sigma-Aldrich
Bovine Serum Albumin, fatty acid free, low endotoxin, lyophilized powder, BioReagent, suitable for cell culture, ≥96% (agarose gel electrophoresis)
Sigma-Aldrich
GSK1702934A, ≥98% (HPLC)