A phytocannabinoid-sensitive phosphorylation switch converts endocannabinoids into alternative lipid GPCR activators.

Love A.; Kihara Y.; Mizuno H.; Nagai K.; Coronel D.; Sheffler D.; Tan V.; Moore B.; Chun J. · bioRxiv : the preprint server for biology · 2026

**Background & Methods** This is a review article that synthesizes research on the biochemical mechanisms of endocannabinoids and their metabolic conversion. The study employed activity-guided brain fractionation, inhibitor profiling, recombinant protein reconstitution, and screening of diacylglycerol kinase (DGK) isozymes to identify the enzymatic pathways responsible for endocannabinoid phosphorylation and subsequent receptor signaling alterations. **Key Findings** • Endocannabinoids (anandamide and 2-arachidonoylglycerol) undergo phosphorylation to form anandamide phosphate (AEAp), which fundamentally shifts their G protein-coupled receptor (GPCR) ligand specificity from cannabinoid receptors (CB1/CB2) to lysophosphatidic acid receptors (LPARs) and the primate-specific bile acid sensory receptor MRGPRX4. • Diacylglycerol kinase theta (DGKθ/DGKQ) was identified as the primary kinase responsible for catalyzing anandamide phosphorylation, demonstrating noncanonical biphasic lipid kinetics in this enzymatic process. • Phytocannabinoids—particularly tetrahydrocannabinolic acid (THCA)—inhibit DGKθ activity, thereby modulating the conversion of endocannabinoids into alternative lipid GPCR activators and linking cannabis pharmacology to broader lipid signaling pathways including lysophosphatidic acid metabolism. **Dosage & Administration** Not reported. **Safety & Adverse Effects** Not reported. **Evidence Quality** As a preprint review article rather than original primary research, this work presents significant limitations in evidence quality. The study synthesizes findings from multiple experimental methodologies but lacks the peer-review validation of a published journal article. The research is mechanistic in nature, focusing on in vitro and cellular/tissue-based investigations rather than clinical trials. No human subject data or in vivo efficacy/safety studies are described. The findings are novel and suggest important connections between cannabis pharmacology and endocannabinoid metabolism, but independent replication and peer review are necessary to establish their validity. The work represents exploratory basic science research and should not be interpreted as having direct clinical applicability without subsequent clinical validation.

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