title: A novel mitochondrial carrier protein Mme1 acts as a yeast mitochondrial magnesium exporter.
abstract: The homeostasis of magnesium (Mg2+), an abundant divalent cation indispensable for many biological processes including mitochondrial functions, is underexplored. Previously, two mitochondrial Mg2+ importers, Mrs2 and Lpe10, were characterized for mitochondrial Mg2+ uptake. We now show that mitochondrial Mg2+ homeostasis is accurately controlled through the combined effects of previously known importers and a novel exporter, Mme1 (mitochondrial magnesium exporter 1). Mme1 belongs to the mitochondrial carrier family and was isolated for its mutation that is able to suppress the mrs2Δ respiration defect. Deletion of MME1 significantly increased steady-state mitochondrial Mg2+ concentration, while overexpression decreased it. Measurements of Mg2+ exit from proteoliposomes reconstituted with purified Mme1 provided definite evidence for Mme1 as an Mg2+ exporter. Our studies identified, for the first time, a mitochondrial Mg2+ exporter that works together with mitochondrial importers to ensure the precise control of mitochondrial Mg2+ homeostasis.
authors.affiliation: State Key Laboratory of Biomembrane and Membrane Biotechnology, School of Life Sciences, Tsinghua University, Beijing 100084, China. Electronic address: cuiyx07@gmail.com.
authors.forename: Yixian
authors.initials: Y
authors.lastname: Cui
authors.affiliation: State Key Laboratory of Biomembrane and Membrane Biotechnology, School of Life Sciences, Tsinghua University, Beijing 100084, China.
authors.forename: Shanke
authors.initials: S
authors.lastname: Zhao
authors.affiliation: State Key Laboratory of Biomembrane and Membrane Biotechnology, School of Life Sciences, Tsinghua University, Beijing 100084, China.
authors.forename: Juan
authors.initials: J
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Biomembrane and Membrane Biotechnology, School of Life Sciences, Tsinghua University, Beijing 100084, China.
authors.forename: Xudong
authors.initials: X
authors.lastname: Wang
authors.affiliation: Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China.
authors.forename: Bingquan
authors.initials: B
authors.lastname: Gao
authors.affiliation: State Key Laboratory of Biomembrane and Membrane Biotechnology, School of Life Sciences, Tsinghua University, Beijing 100084, China.
authors.forename: Qiangwang
authors.initials: Q
authors.lastname: Fan
authors.affiliation: Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China.
authors.forename: Fei
authors.initials: F
authors.lastname: Sun
authors.affiliation: State Key Laboratory of Biomembrane and Membrane Biotechnology, School of Life Sciences, Tsinghua University, Beijing 100084, China. Electronic address: zhoubing@mail.tsinghua.edu.cn.
authors.forename: Bing
authors.initials: B
authors.lastname: Zhou
mesh_terms: D001692:Biological Transport; D027682:Cation Transport Proteins / Q000235:genetics / Q000502:physiology*; D007473:Ion Channels / Q000037:antagonists & inhibitors / Q000378:metabolism; D008274:Magnesium / Q000378:metabolism*; D008565:Membrane Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism; D008928:Mitochondria / Q000378:metabolism*; D024101:Mitochondrial Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism / Q000502:physiology*; D030781:Organisms, Genetically Modified; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism / Q000502:physiology*
chemical_list: D027682:Cation Transport Proteins; D007473:Ion Channels; C423310:Lpe10 protein, S cerevisiae; C114838:MRS2 protein, S cerevisiae; D008565:Membrane Proteins; D024101:Mitochondrial Proteins; D029701:Saccharomyces cerevisiae Proteins; C000601113:mitochondrial magnesium exporter 1, S cerevisiae; D008274:Magnesium
keywords: Lpe10; Mme1; Mrs2; mitochondrial Mg(2+) exporter; proteoliposome