Protein transport into mitochondria

Mitochondria are made up of two membrane systems that subdivide this organe lle into two aqueous subcompartments: the matrix, which is enclosed by the inner membrane, and the intermembrane space, which is located between the i nner and the outer membrane. Protein import into mitochondria is a complex reaction, as every protein has to be routed to its specific destination wit hin the organelle. In the past few years, studies with mitochondria of Neur ospora crassa and Saccharomyces cerevisiae have led to the identification o f four distinct translocation machineries that are conserved among eukaryot es. These translocases, in a concerted fashion, mediate import and sorting of proteins into the mitochondrial subcompartments.