Isolation of contact sites between inner and outer mitochondrial membranes

Abstract

Mitochondria are essential organelles of all eukaryotic cells. They perform a plethora of important metabolic functions and have a highly complex architecture that differs drastically between different cells and tissues. Mitochondria are delimited from the cytosol by the mitochondrial envelope that consists of the outer membrane and the inner membrane. The inner membrane is subdivided into the inner boundary membrane that runs parallel to the outer membrane and the crista membrane. Both sections of the inner membrane are linked by crista junctions. A further important architectural element of mitochondria are the contact sites between outer membrane and inner membrane. These sites were observed a long time ago by classical electron microscopy, but their molecular structure was identified only recently when it was recognized that proteins of crista junctions and proteins of the outer membrane are responsible for these strong contacts. Mitochondrial function is severely affected when contact sites are disturbed. This underlines the notion that mitochondrial architecture and function are intimately connected. In the following a method is described to generate and to isolate membrane vesicles from isolated yeast mitochondria that contain these contact sites.