Fig. 4. Subunit stoichiometry and function of the RKR/AAA and A457P mutant.

a Electric field of the intracellular side of wildtype and mutant NET. The protein’s solvent-accessible surface is shown as white surface except for the residues replaced by the mutation, which are green. Red surface indicates the negative electric isopotential of -2 kT/e while blue surface shows the +2 kT/e. Possible protein-lipid interactions are depicted by showing the inner leaflet of a modeled POPC + cholesterol membrane indicated as orange lines and the phosphate headgroups as spheres. b Total d-methamphetamine-induced substrate efflux for the RKR/AAA mutant under PIP₂-depleted conditions was statistically indifferent from control. Bars represent mean efflux (± SD) of five experiments, normalized to basal efflux. Efflux for wildtype NET is included as shaded bars for comparison. c Subunit distribution of the RKR/AAA mutant. Each data point represents an independent experiment with TOCCSL runs on ten cells. Bars represent means ± SD. d The average oligomeric state of the RKR/AAA mutant was indifferent from wildtype. e NET-RKR/AAA surface densities of the imaged cells did not differ from wildtype NET densities. f Subunit distribution of the A457P mutant. Each data point represents an independent experiment with TOCCSL runs on ten cells. Bars represent means ± SD. g The average oligomeric state of the A457P mutant was indifferent from wildtype. h NET-A457P surface densities of the imaged cells did not differ from wildtype NET densities.