FIGURE 5.

Effect of negative electric surface potentials of proteoliposomes on G protein activation by CB₂ receptor. a, scheme showing sample preparation with variations of anionic lipid content (CHS or POPS) in proteoliposomes. All proteoliposomes contain a basal level of 25 mol % of CHS (marked with asterisk) to stabilize CB₂ receptor in micelles. Either an extra 16 mol % of CHS was added at a constant POPC/POPS molar ratio of 4/1, or an equivalent amount of Chol was added instead of CHS, or the POPC/POPS ratio was varied from 5/0 to 1/4. b, influence of an extra 16 mol % of CHS or Chol on G protein activation by CB₂ receptor. The control sample I (G protein activation = 1) had a composition of CB₂/POPC/POPS/CHS, 1/520/130/220 (mol/mol/mol/mol). Results are the average of two independently prepared samples for each composition assayed two times each (n = 4). c, G protein activation by CB₂ receptor as a function of the POPC/POPS molar ratio. The G protein activation of the sample with a composition of CB₂/POPC/CHS, 1/650/220 (mol/mol/mol), labeled as 5/0 (control II), was set to 1. Results are the average of four G protein activation assays conducted on one set of five samples (n = 4).