Figure 3. BAX mediates LMP in vivo and in purified brain lysosomes. (A) Enzymatic activities of lysosomal enzymes ACP2 (left panel) and CTSD (right panel) in cytosolic, lysosomal-free fractions from the ventral midbrain of MPTP-treated wild-type (WT) or BAX-deficient (KO) mice, 2 h post-MPTP, expressed as percentage of total enzymatic activity (lysosomal+cytosolic). *P < 0.05, compared with WT saline-injected mice; #P < 0.05, compared with WT MPTP-treated mice. (B) Enzymatic activities of ACP2 (left panel) and β-hexosaminidase (right panel) in supernatant fractions from fresh purified mouse brain lysosomes after incubation with recombinant BAX (100 nM for 30 min), in the presence or the absence of Bci (2 μM). (C) Enzymatic activities of ACP2 (left panel) and β-hexosaminidase (right panel) in supernatant fractions from fresh purified mouse brain lysosomes after incubation with either H₂O₂ (1 mM) or NH₄Cl (40 mM) for 30 min, in the presence or the absence of Bci (2 μM). In all panels, data represent mean ± SEM. In (B and C), at least 3 independent experiments were performed. In (A), n = 4 animals per group.