Overview

We are studying the molecular architecture and biogenesis of mitochondria. Both areas are closely interconnected since function of mitochondria requires intact architecture. Mitochondria are made up of two different membranes, the outer membrane (OM) and the inner membrane (IM). The IM, enclosing the matrix, is subdivided into the inner boundary membrane (IBM) and the cristae, with the crista junctions (CJ) as joining narrow elements. OM and IM are connected by contact sites (CS). We identified protein components of the MICOS complex that forms the mitochondrial CS and further emphasis is on the characterization of their specific function within this complex. The majority of the mitochondrial proteins are translated in the cytosol and transported into the various mitochondrial subcompartments by protein translocases. We have investigated these complex molecular machines, so far six different ones with different specificities, all of them highly complex in their structures and mechanisms. Current emphasis is on the seventh translocase which is a member of the AAA-ATPase family. We are using classical and molecular yeast genetics, biochemical and biophysical methods for protein identification, isolation and characterisation, mass spectrometry (SILAC) and various kinds of electron microscopy.