title: Physiological Characterization of a Plant Mitochondrial Calcium Uniporter in Vitro and in Vivo.
abstract: Over the recent years, several proteins that make up the mitochondrial calcium uniporter complex (MCUC) mediating Ca2+uptake into the mitochondrial matrix have been identified in mammals, including the channel-forming protein MCU. Although six MCU gene homologs are conserved in the model plant Arabidopsis (Arabidopsis thaliana) in which mitochondria can accumulate Ca2+, a functional characterization of plant MCU homologs has been lacking. Using electrophysiology, we show that one isoform, AtMCU1, gives rise to a Ca2+-permeable channel activity that can be observed even in the absence of accessory proteins implicated in the formation of the active mammalian channel. Furthermore, we provide direct evidence that AtMCU1 activity is sensitive to the mitochondrial calcium uniporter inhibitors Ruthenium Red and Gd3+, as well as to the Arabidopsis protein MICU, a regulatory MCUC component. AtMCU1 is prevalently expressed in roots, localizes to mitochondria, and its absence causes mild changes in Ca2+dynamics as assessed by in vivo measurements in Arabidopsis root tips. Plants either lacking or overexpressing AtMCU1 display root mitochondria with altered ultrastructure and show shorter primary roots under restrictive growth conditions. In summary, our work adds evolutionary depth to the investigation of mitochondrial Ca2+transport, indicates that AtMCU1, together with MICU as a regulator, represents a functional configuration of the plant mitochondrial Ca2+uptake complex with differences to the mammalian MCUC, and identifies a new player of the intracellular Ca2+regulation network in plants.
authors.affiliation: Department of Biology (E.T., L.C., E.F., S.D.B., V.L., F.L.S., I.S.) and Department of Biomedical Sciences (A.R., R.R.), University of Padova, 35121 Padova, Italy; ildi@civ.bio.unipd.it enrico.teardo@unipd.it.|CNR Institute of Neuroscience, Padova, Italy, Department of Biomedical Sciences, University of Padua, 35121 Padova, Italy (E.T., I.S.); ildi@civ.bio.unipd.it enrico.teardo@unipd.it.|Plant Energy Biology Lab, Institute of Crop Science and Resource Conservation (INRES), University of Bonn, 53113 Bonn, Germany (S.W., P.F., M.S.); ildi@civ.bio.unipd.it enrico.teardo@unipd.it.|Department of Biosciences, University of Milan, 20133 Milan, Italy (S.B., A.C.); and ildi@civ.bio.unipd.it enrico.teardo@unipd.it.|Institute of Biophysics, Consiglio Nazionale delle Ricerche, 20133 Milan, Italy (A.C.) ildi@civ.bio.unipd.it enrico.teardo@unipd.it.
authors.forename: Enrico
authors.initials: E
authors.lastname: Teardo
authors.affiliation: Department of Biology (E.T., L.C., E.F., S.D.B., V.L., F.L.S., I.S.) and Department of Biomedical Sciences (A.R., R.R.), University of Padova, 35121 Padova, Italy.|CNR Institute of Neuroscience, Padova, Italy, Department of Biomedical Sciences, University of Padua, 35121 Padova, Italy (E.T., I.S.).|Plant Energy Biology Lab, Institute of Crop Science and Resource Conservation (INRES), University of Bonn, 53113 Bonn, Germany (S.W., P.F., M.S.).|Department of Biosciences, University of Milan, 20133 Milan, Italy (S.B., A.C.); and.|Institute of Biophysics, Consiglio Nazionale delle Ricerche, 20133 Milan, Italy (A.C.).
authors.forename: Luca
authors.initials: L
authors.lastname: Carraretto
authors.affiliation: Department of Biology (E.T., L.C., E.F., S.D.B., V.L., F.L.S., I.S.) and Department of Biomedical Sciences (A.R., R.R.), University of Padova, 35121 Padova, Italy.|CNR Institute of Neuroscience, Padova, Italy, Department of Biomedical Sciences, University of Padua, 35121 Padova, Italy (E.T., I.S.).|Plant Energy Biology Lab, Institute of Crop Science and Resource Conservation (INRES), University of Bonn, 53113 Bonn, Germany (S.W., P.F., M.S.).|Department of Biosciences, University of Milan, 20133 Milan, Italy (S.B., A.C.); and.|Institute of Biophysics, Consiglio Nazionale delle Ricerche, 20133 Milan, Italy (A.C.).
authors.forename: Stephan
authors.identifier: 0000-0001-5369-7911
authors.initials: S
authors.lastname: Wagner
authors.affiliation: Department of Biology (E.T., L.C., E.F., S.D.B., V.L., F.L.S., I.S.) and Department of Biomedical Sciences (A.R., R.R.), University of Padova, 35121 Padova, Italy.|CNR Institute of Neuroscience, Padova, Italy, Department of Biomedical Sciences, University of Padua, 35121 Padova, Italy (E.T., I.S.).|Plant Energy Biology Lab, Institute of Crop Science and Resource Conservation (INRES), University of Bonn, 53113 Bonn, Germany (S.W., P.F., M.S.).|Department of Biosciences, University of Milan, 20133 Milan, Italy (S.B., A.C.); and.|Institute of Biophysics, Consiglio Nazionale delle Ricerche, 20133 Milan, Italy (A.C.).
authors.forename: Elide
authors.initials: E
authors.lastname: Formentin
authors.affiliation: Department of Biology (E.T., L.C., E.F., S.D.B., V.L., F.L.S., I.S.) and Department of Biomedical Sciences (A.R., R.R.), University of Padova, 35121 Padova, Italy.|CNR Institute of Neuroscience, Padova, Italy, Department of Biomedical Sciences, University of Padua, 35121 Padova, Italy (E.T., I.S.).|Plant Energy Biology Lab, Institute of Crop Science and Resource Conservation (INRES), University of Bonn, 53113 Bonn, Germany (S.W., P.F., M.S.).|Department of Biosciences, University of Milan, 20133 Milan, Italy (S.B., A.C.); and.|Institute of Biophysics, Consiglio Nazionale delle Ricerche, 20133 Milan, Italy (A.C.).
authors.forename: Smrutisanjita
authors.identifier: 0000-0001-8749-6130
authors.initials: S
authors.lastname: Behera
authors.affiliation: Department of Biology (E.T., L.C., E.F., S.D.B., V.L., F.L.S., I.S.) and Department of Biomedical Sciences (A.R., R.R.), University of Padova, 35121 Padova, Italy.|CNR Institute of Neuroscience, Padova, Italy, Department of Biomedical Sciences, University of Padua, 35121 Padova, Italy (E.T., I.S.).|Plant Energy Biology Lab, Institute of Crop Science and Resource Conservation (INRES), University of Bonn, 53113 Bonn, Germany (S.W., P.F., M.S.).|Department of Biosciences, University of Milan, 20133 Milan, Italy (S.B., A.C.); and.|Institute of Biophysics, Consiglio Nazionale delle Ricerche, 20133 Milan, Italy (A.C.).
authors.forename: Sara
authors.identifier: 0000-0003-3797-6966
authors.initials: S
authors.lastname: De Bortoli
authors.affiliation: Department of Biology (E.T., L.C., E.F., S.D.B., V.L., F.L.S., I.S.) and Department of Biomedical Sciences (A.R., R.R.), University of Padova, 35121 Padova, Italy.|CNR Institute of Neuroscience, Padova, Italy, Department of Biomedical Sciences, University of Padua, 35121 Padova, Italy (E.T., I.S.).|Plant Energy Biology Lab, Institute of Crop Science and Resource Conservation (INRES), University of Bonn, 53113 Bonn, Germany (S.W., P.F., M.S.).|Department of Biosciences, University of Milan, 20133 Milan, Italy (S.B., A.C.); and.|Institute of Biophysics, Consiglio Nazionale delle Ricerche, 20133 Milan, Italy (A.C.).
authors.forename: Véronique
authors.initials: V
authors.lastname: Larosa
authors.affiliation: Department of Biology (E.T., L.C., E.F., S.D.B., V.L., F.L.S., I.S.) and Department of Biomedical Sciences (A.R., R.R.), University of Padova, 35121 Padova, Italy.|CNR Institute of Neuroscience, Padova, Italy, Department of Biomedical Sciences, University of Padua, 35121 Padova, Italy (E.T., I.S.).|Plant Energy Biology Lab, Institute of Crop Science and Resource Conservation (INRES), University of Bonn, 53113 Bonn, Germany (S.W., P.F., M.S.).|Department of Biosciences, University of Milan, 20133 Milan, Italy (S.B., A.C.); and.|Institute of Biophysics, Consiglio Nazionale delle Ricerche, 20133 Milan, Italy (A.C.).
authors.forename: Philippe
authors.identifier: 0000-0001-6379-853X
authors.initials: P
authors.lastname: Fuchs
authors.affiliation: Department of Biology (E.T., L.C., E.F., S.D.B., V.L., F.L.S., I.S.) and Department of Biomedical Sciences (A.R., R.R.), University of Padova, 35121 Padova, Italy.|CNR Institute of Neuroscience, Padova, Italy, Department of Biomedical Sciences, University of Padua, 35121 Padova, Italy (E.T., I.S.).|Plant Energy Biology Lab, Institute of Crop Science and Resource Conservation (INRES), University of Bonn, 53113 Bonn, Germany (S.W., P.F., M.S.).|Department of Biosciences, University of Milan, 20133 Milan, Italy (S.B., A.C.); and.|Institute of Biophysics, Consiglio Nazionale delle Ricerche, 20133 Milan, Italy (A.C.).
authors.forename: Fiorella
authors.initials: F
authors.lastname: Lo Schiavo
authors.affiliation: Department of Biology (E.T., L.C., E.F., S.D.B., V.L., F.L.S., I.S.) and Department of Biomedical Sciences (A.R., R.R.), University of Padova, 35121 Padova, Italy.|CNR Institute of Neuroscience, Padova, Italy, Department of Biomedical Sciences, University of Padua, 35121 Padova, Italy (E.T., I.S.).|Plant Energy Biology Lab, Institute of Crop Science and Resource Conservation (INRES), University of Bonn, 53113 Bonn, Germany (S.W., P.F., M.S.).|Department of Biosciences, University of Milan, 20133 Milan, Italy (S.B., A.C.); and.|Institute of Biophysics, Consiglio Nazionale delle Ricerche, 20133 Milan, Italy (A.C.).
authors.forename: Anna
authors.initials: A
authors.lastname: Raffaello
authors.affiliation: Department of Biology (E.T., L.C., E.F., S.D.B., V.L., F.L.S., I.S.) and Department of Biomedical Sciences (A.R., R.R.), University of Padova, 35121 Padova, Italy.|CNR Institute of Neuroscience, Padova, Italy, Department of Biomedical Sciences, University of Padua, 35121 Padova, Italy (E.T., I.S.).|Plant Energy Biology Lab, Institute of Crop Science and Resource Conservation (INRES), University of Bonn, 53113 Bonn, Germany (S.W., P.F., M.S.).|Department of Biosciences, University of Milan, 20133 Milan, Italy (S.B., A.C.); and.|Institute of Biophysics, Consiglio Nazionale delle Ricerche, 20133 Milan, Italy (A.C.).
authors.forename: Rosario
authors.initials: R
authors.lastname: Rizzuto
authors.affiliation: Department of Biology (E.T., L.C., E.F., S.D.B., V.L., F.L.S., I.S.) and Department of Biomedical Sciences (A.R., R.R.), University of Padova, 35121 Padova, Italy.|CNR Institute of Neuroscience, Padova, Italy, Department of Biomedical Sciences, University of Padua, 35121 Padova, Italy (E.T., I.S.).|Plant Energy Biology Lab, Institute of Crop Science and Resource Conservation (INRES), University of Bonn, 53113 Bonn, Germany (S.W., P.F., M.S.).|Department of Biosciences, University of Milan, 20133 Milan, Italy (S.B., A.C.); and.|Institute of Biophysics, Consiglio Nazionale delle Ricerche, 20133 Milan, Italy (A.C.).
authors.forename: Alex
authors.identifier: 0000-0002-2628-1176
authors.initials: A
authors.lastname: Costa
authors.affiliation: Department of Biology (E.T., L.C., E.F., S.D.B., V.L., F.L.S., I.S.) and Department of Biomedical Sciences (A.R., R.R.), University of Padova, 35121 Padova, Italy.|CNR Institute of Neuroscience, Padova, Italy, Department of Biomedical Sciences, University of Padua, 35121 Padova, Italy (E.T., I.S.).|Plant Energy Biology Lab, Institute of Crop Science and Resource Conservation (INRES), University of Bonn, 53113 Bonn, Germany (S.W., P.F., M.S.).|Department of Biosciences, University of Milan, 20133 Milan, Italy (S.B., A.C.); and.|Institute of Biophysics, Consiglio Nazionale delle Ricerche, 20133 Milan, Italy (A.C.).
authors.forename: Markus
authors.identifier: 0000-0003-0796-8308
authors.initials: M
authors.lastname: Schwarzländer
authors.affiliation: Department of Biology (E.T., L.C., E.F., S.D.B., V.L., F.L.S., I.S.) and Department of Biomedical Sciences (A.R., R.R.), University of Padova, 35121 Padova, Italy; ildi@civ.bio.unipd.it enrico.teardo@unipd.it.|CNR Institute of Neuroscience, Padova, Italy, Department of Biomedical Sciences, University of Padua, 35121 Padova, Italy (E.T., I.S.); ildi@civ.bio.unipd.it enrico.teardo@unipd.it.|Plant Energy Biology Lab, Institute of Crop Science and Resource Conservation (INRES), University of Bonn, 53113 Bonn, Germany (S.W., P.F., M.S.); ildi@civ.bio.unipd.it enrico.teardo@unipd.it.|Department of Biosciences, University of Milan, 20133 Milan, Italy (S.B., A.C.); and ildi@civ.bio.unipd.it enrico.teardo@unipd.it.|Institute of Biophysics, Consiglio Nazionale delle Ricerche, 20133 Milan, Italy (A.C.) ildi@civ.bio.unipd.it enrico.teardo@unipd.it.
authors.forename: Ildiko
authors.identifier: 0000-0002-3637-3947
authors.initials: I
authors.lastname: Szabò
mesh_terms: D017360:Arabidopsis / Q000166:cytology / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism; D015220:Calcium Channels / Q000235:genetics / Q000378:metabolism*; D002135:Calcium-Binding Proteins / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D008928:Mitochondria / Q000235:genetics / Q000378:metabolism / Q000648:ultrastructure; D009154:Mutation; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics; D018517:Plant Roots / Q000235:genetics / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D015220:Calcium Channels; D002135:Calcium-Binding Proteins; C000623002:MCU1 protein, Arabidopsis; C000623003:MCU2 protein, Arabidopsis; C000610965:MICU protein, Arabidopsis; D010940:Plant Proteins; C034703:mitochondrial calcium uniporter; D002118:Calcium