Effects of pH and specific mutations on the ATP8A2-related current transients. (A and B) Current transients induced by 100 µM ATP concentration jumps on 90PC:10PS (A) and 50PC:50PE (B) proteoliposomes containing ATP8A2 in basic medium, pH 7.5 (black lines) or 6.7 (red lines). (C and D) Current transients observed following 100 µM ATP concentration jumps on 90PC:10PS proteoliposomes containing ATP8A2 wild-type enzyme (C and D, black lines), mutant E198Q (C, green line), or mutant I364M (D, green line) in basic medium, pH 7.5.