The Role of Mitochondrial Chaperone Tumor Necrosis Factor-associated Protein 1 (TRAP1) in the Regulation of Apoptosis

Abstract

An increase of mitochondrial membrane permeability is one of the key events in apoptosis, since it leads to the release of mitochondrial apoptogenic factors, such as cytochrome c, into the cytoplasm that activate downstream target of apoptotic cell death. Bcl-2 family is one of the best-characterized proteins that directly regulate mitochondrial functions. A major role of the Bcl-2 family of proteins is to alter mitochondrial membrane permeability, thus controlling the release of caspase-activating cytochrome c. Recent reports describe about involvement of interesting apoptogenic regulators other than Bcl-2 family in regulation of mitochondrial function. Tumor necrosis factor receptor-associated protein 1 (TRAP1) is a member of the heat-shock family of mitochondrial proteins, and substantially homologous to members of the 90-kDa families of heat-shock proteins (HSP90). TRAP1 seems to have specific functions differ from those of other members of the HSP90 family. Downregulation of TRAP1 expression enhances the release of cytochrome c from mitochondria. Moreover, reactive oxygen species (ROS) are involved in the regulation of the TRAP1 expression, indicating that TRAP1 is a sensor that involved in ROS mediated regulation of apoptosis. Here, we describe the mechanisms underlying the regulation of mitochondrial functions during apoptosis by TRAP1.