Role of ATP in GSH metabolism in α-syn N27 clones (A and B are in vitro data). (A) Effect of MG132 on GCL activity in the absence of exogenous ATP in α-syn-expressing vs untreated cells (C, control; W, wild type; M, A53T mutant). *p< 0.5 A53T compared to control cells; **p< 0.005 A53T compared to control cells. (B) Total ATP content in α-syn cells compared to control in the presence and absence of lactacystin (2.5 μM). *p< 0.001 compared to untreated A53T cells, ns, not significant compared to untreated cells.