Mutations in UCP2 in Congenital Hyperinsulinism Reveal a Role for Regulation of Insulin Secretion
Figure 3
Comparison of the proton leak kinetics of yeast spheroplasts.
Spheroplasts were isolated from control (pYeDP plasmid, black circles), wild type UCP2 (pYeDP-hUCP2, black triangles) and mutated (as found in patient 1 and 2) UCP2 (pYeDP-hU2Patient1, open diamonds and pYeDP-hU2Patient2, grey squares) yeasts as described in “Materials and Methods” section. Mitochondrial membrane potential and respiratory rate were simultaneously recorded and varied by titration with potassium cyanide in the presence of NADH. These experiments were performed in the presence of oligomycin using the same amount of respiratory chain for the different types of spheroplasts as determined from the maximal respiratory rate in the presence of FCCP (for details see “Materials and Methods” section). Respiratory rate (y axis) is represented as the percentage from the maximal respiratory rate (Vmax) in the presence of FCCP. Membrane potential (x axis) is represented as the percentage from the highest membrane potential in state 4 of respiration. Results are means±S.E.M. of three independent experiments performed at least in duplicate.