Mechanism of membrane-tethered mitochondrial protein synthesis

Abstract

Making the energy makers Within a mitochondrion, the powerhouse of eukaryotic cells, synthesis of the specialized transmembrane proteins of the electron transport chain is performed by dedicated mitoribosomes. The mechanism by which mitoribosomes couple protein synthesis with membrane insertion is poorly understood. Itoh et al. determined structures of the human mitoribosome during nascent chain synthesis while bound to its membrane insertase. These structures revealed a series of coordinated conformational changes within the polypeptide exit tunnel. The gating mechanism offers a fundamental molecular insight into how membrane proteins are synthesized in human mitochondria. Science , this issue p. 846