title: Redox-regulation of protein import into chloroplasts and mitochondria: similarities and differences.
abstract: Redox signals play important roles in many developmental and metabolic processes, in particular in chloroplasts and mitochondria. Furthermore, redox reactions are crucial for protein folding via the formation of inter- or intramolecular disulfide bridges. Recently, redox signals were described to be additionally involved in regulation of protein import: in mitochondria, a disulfide relay system mediates retention of cystein-rich proteins in the intermembrane space by oxidizing them. Two essential proteins, the redox-activated receptor Mia40 and the sulfhydryl oxidase Erv1 participate in this pathway. In chloroplasts, it becomes apparent that protein import is affected by redox signals on both the outer and inner envelope: at the level of the Toc complex (translocon at the outer envelope of chloroplasts), the formation/reduction of disulfide bridges between the Toc components has a strong influence on import yield. Moreover, the stromal metabolic redox state seems to be sensed by the Tic complex (translocon at the inner envelope of chloroplasts) that is able to adjust translocation efficiency of a subgroup of redox-related preproteins accordingly. This review summarizes the current knowledge of these redox-regulatory pathways and focuses on similarities and differences between chloroplasts and mitochondria.
authors.affiliation: Munich Center for Integrated Protein Science CiPS(M-), Ludwig-Maximilians-Universität München, Munich, Germany.
authors.forename: Anna
authors.initials: A
authors.lastname: Stengel
authors.forename: J Philipp
authors.initials: JP
authors.lastname: Benz
authors.forename: Jürgen
authors.initials: J
authors.lastname: Soll
authors.forename: Bettina
authors.initials: B
authors.lastname: Bölter
mesh_terms: D002736:Chloroplasts / Q000378:metabolism*; D008928:Mitochondria / Q000378:metabolism*; D033681:Mitochondrial Membrane Transport Proteins / Q000378:metabolism; D009249:NADP / Q000378:metabolism; D010084:Oxidation-Reduction; D010088:Oxidoreductases / Q000378:metabolism; D018521:Plant Physiological Phenomena; D010940:Plant Proteins / Q000378:metabolism; D021381:Protein Transport; D050862:Oxidoreductases Acting on Sulfur Group Donors
chemical_list: D033681:Mitochondrial Membrane Transport Proteins; D009249:NADP; D010088:Oxidoreductases; D010940:Plant Proteins; D050862:Oxidoreductases Acting on Sulfur Group Donors