Membrane lipids are key-modulators of the endocannabinoid-hydrolase FAAH

Lipid composition is expected to play an important role in modulating membrane enzyme activity, in particular if the substrates are themselves lipid molecules. A paradigmatic case is fatty acid amide hydrolase (FAAH), a critical enzyme in terminating the endocannabinoid signalling and an important therapeutic target. Here, using a combined experimental and computational approach, we show that membrane lipids modulate structure, subcellular localization and activity of FAAH. We report that FAAH dimer is stabilized by the lipid bilayer and shows higher membrane binding affinity and enzymatic activity within membranes containing both cholesterol and the natural FAAH substrate, anandamide (AEA). Additionally, colocalization of cholesterol, AEA, and FAAH in mouse neuroblastoma cells suggests a mechanism through which cholesterol increases the substrate accessibility of FAAH.