Figure 9.

Model for the dynamics, interplay and physiological impact of the cytosolic and mitochondrial glutathione pools. (A) Fast cross-talk via porins in the OMM takes place between the glutathione pools of the IMS and the cytosol. Because of this dynamic glutathione exchange the cytosolic glutathione reductase system exerts the major influence on the composition of the IMS glutathione pool. Although the matrix relies on glutathione delivery from the cytosol for replenishing its glutathione pool, E_GSH[matrix] is maintained by matrix-localized reducing systems as GSSG cannot be exported from the matrix. (B) The oxidoreductase of the IMS Mia40 is in vivo partially reduced. Its redox state is maintained by reducing influences from the local glutathione pool (and newly imported reduced substrates), and oxidizing influences from the sulphhydryloxidase Erv1. In-vivo Erv1 can shuttle its electrons either directly to oxygen or via the respiratory chain. This latter pathway might only be required under conditions of low oxygen.