Background:Structural and functional studies on G protein-coupled receptor (GPCR) benefit from reconstitution of pure GPCR into lipid bilayers. Results: Cannabinoid CB 2 receptor was successfully reconstituted and the effect of anionic lipids and cholesterol on G protein activation was studied. Conclusion: G protein activation increased with anionic lipid content up to ϳ50 mol %. Significance: Anionic lipids regulate signal transduction by CB 2 receptor and possibly other class A GPCR.