FIGURE 10.

Schematic diagram of the proposed molecular mechanism of SOUL. Subeffective concentration of Ca²⁺ or free radicals together with SOUL induces permeability transition accompanied by the loss of mitochondrial membrane potential and the release of intermembrane proteins, eventually leading to cell death. CsA, suppression of cyclophilin D, Bcl-2, or Bcl-x_L prevents this process, indicating the direct effect of SOUL on the mitochondrial permeability transition pore (mPTP). Established components of the mitochondrial permeability transition pore are indicated schematically. ANT, adenine nucleotide translocator; Cyp-D, cyclophilin D; CL, adenine nucleotide translocator-associated cardiolipin; HK, hexokinase; Bcl-2, B-cell-associated leukemia protein 2; Bcl-x_L, B-cell-associated leukemia protein x_L. Note that the exact stochiometry and composition of the mitochondrial permeability transition pore are elusive. Moreover, the mitochondrial permeability transition pore composition is not fully illustrated and may be cell type-dependent.