title: Specific targeting of proteins to outer envelope membranes of endosymbiotic organelles, chloroplasts, and mitochondria.
abstract: Chloroplasts and mitochondria are endosymbiotic organelles thought to be derived from endosymbiotic bacteria. In present-day eukaryotic cells, these two organelles play pivotal roles in photosynthesis and ATP production. In addition to these major activities, numerous reactions, and cellular processes that are crucial for normal cellular functions occur in chloroplasts and mitochondria. To function properly, these organelles constantly communicate with the surrounding cellular compartments. This communication includes the import of proteins, the exchange of metabolites and ions, and interactions with other organelles, all of which heavily depend on membrane proteins localized to the outer envelope membranes. Therefore, correct and efficient targeting of these membrane proteins, which are encoded by the nuclear genome and translated in the cytosol, is critically important for organellar function. In this review, we summarize the current knowledge of the mechanisms of protein targeting to the outer membranes of mitochondria and chloroplasts in two different directions, as well as targeting signals and cytosolic factors.
authors.affiliation: Cellular Systems Biology, Department of Life Sciences, Pohang University of Science and Technology Pohang, South Korea.
authors.forename: Junho
authors.initials: J
authors.lastname: Lee
authors.affiliation: Cellular Systems Biology, Department of Life Sciences, Pohang University of Science and Technology Pohang, South Korea.
authors.forename: Dae Heon
authors.initials: DH
authors.lastname: Kim
authors.affiliation: Cellular Systems Biology, Department of Life Sciences, Pohang University of Science and Technology Pohang, South Korea ; Division of Integrative Biosciences and Bioengineering, Pohang University of Science and Technology Pohang, South Korea.
authors.forename: Inhwan
authors.initials: I
authors.lastname: Hwang
keywords: AKR2; chloroplasts; endosymbiotic organelles; mitochondria; outer membrane proteins; signal-anchored proteins; tail-anchored protein; β-barrel proteins