Abstract
[Purpose] Recently we have reported that mitochondrial membrane bound glutathione transferase (MtMGST1) contributes to the mitochondrial permeability transition (MPT) (Lee et al., Toxicol Appl Pharmacol 2008) and MtMGST1 in the inner membrane (IM) could form disulfide-linked high molecular weight protein (HMP) with MPT regulator proteins, adenine nucleotide translocator (ANT) and cyclophilin D by the oxidant peroxynitrite (PON) (Imaizumi and Aniya, Arch. Biochem. Biophys. 2011). In the present study, we purified IM-MGST1 and isoforms of ANT and examined whether IM-MGST1 directly interacts with ANT followed by HMP formation by PON treatment. [Method] IM-MGST1 and ANT were purified from IM as described previously. IM-MGST1 and ANT were incubated with PON in the presence or absence of phospholipids, and then GST activity and HMP formation were measured by the method of Habig and immunoblot analysis, respectively. [Results and Discussion] IM-MGST1 and two types of ANT (30 kDa and 48 kDa) were purified from IM. IM-MGST1 activity was increased by incubation with ANTs, cardiolipin and PON. When IM-MGST1 was incubated with ANTs in the presence of PON, HMP was observed dominantly by incubation with ANT fraction with 48 kDa. Thus it was confirmed that IM-MGST1 activity is modulated by cardiolipin and ANTs and that IM-MGST1 directly interacts with ANT and can form disulfide-linked HMP in the presence of PON. These results suggest that IM-MGST1 attributes to a MPT pore formation with ANT in oxidative stress.
