title: Thylakoid Membrane Architecture inSynechocystisDepends on CurT, a Homolog of the Granal CURVATURE THYLAKOID1 Proteins.
abstract: Photosynthesis occurs in thylakoids, a highly specialized membrane system. In the cyanobacteriumSynechocystissp PCC 6803 (hereafterSynechocystis6803), the thylakoids are arranged parallel to the plasma membrane and occasionally converge toward it to form biogenesis centers. The initial steps in PSII assembly are thought to take place in these regions, which contain a membrane subcompartment harboring the early assembly factor PratA and are referred to as PratA-defined membranes (PDMs). Loss of CurT, theSynechocystis6803 homolog ofArabidopsis thalianagrana-shaping proteins of the CURVATURE THYLAKOID1 family, results in disrupted thylakoid organization and the absence of biogenesis centers. As a consequence, PSII is less efficiently assembled and accumulates to only 50% of wild-type levels. CurT induces membrane curvature in vitro and is distributed all over the thylakoids, with local concentrations at biogenesis centers. There it forms a sophisticated tubular network at the cell periphery, as revealed by live-cell imaging. CurT is part of several high molecular mass complexes, and Blue Native/SDS-PAGE and isoelectric focusing demonstrated that different isoforms associate with PDMs and thylakoids. Moreover, CurT deficiency enhances sensitivity to osmotic stress, adding a level of complexity to CurT function. We propose that CurT is crucial for the differentiation of membrane architecture, including the formation of PSII-related biogenesis centers, inSynechocystis6803.
authors.affiliation: Molekulare Pflanzenwissenschaften, Ludwig-Maximilians-Universität München, Biozentrum, 82152 Planegg-Martinsried, Germany.
authors.forename: Steffen
authors.initials: S
authors.lastname: Heinz
authors.affiliation: Molekulare Pflanzenwissenschaften, Ludwig-Maximilians-Universität München, Biozentrum, 82152 Planegg-Martinsried, Germany.
authors.forename: Anna
authors.initials: A
authors.lastname: Rast
authors.affiliation: Molekulare Pflanzenwissenschaften, Ludwig-Maximilians-Universität München, Biozentrum, 82152 Planegg-Martinsried, Germany.
authors.forename: Lin
authors.initials: L
authors.lastname: Shao
authors.affiliation: Department of Molecular and Cellular Biology, FAS Center for Systems Biology, Harvard University, Cambridge, Massachusetts 02138.
authors.forename: Andrian
authors.initials: A
authors.lastname: Gutu
authors.affiliation: Biochemie und Physiologie der Pflanzen, Ludwig-Maximilians-Universität München, Biozentrum, 82152 Planegg-Martinsried, Germany.|Munich Centre for Integrated Protein Science CiPSM, Ludwig-Maximilians-Universität München, Department of Chemistry and Biochemistry, 81377 Munich, Germany.
authors.forename: Irene L
authors.identifier: http://orcid.org/0000-0002-5475-9210
authors.initials: IL
authors.lastname: Gügel
authors.affiliation: Biochemie der Pflanzen, Ruhr-Universität Bochum, 44801 Bochum, Germany.|Max-Planck-Institut für Chemische Energiekonversion, 45470 Mülheim an der Ruhr, Germany.
authors.forename: Eiri
authors.initials: E
authors.lastname: Heyno
authors.affiliation: Molekularbiologie der Pflanzen, Ludwig-Maximilians-Universität München, Biozentrum, 82152 Planegg-Martinsried, Germany.
authors.forename: Mathias
authors.initials: M
authors.lastname: Labs
authors.affiliation: Molekulare Pflanzenwissenschaften, Ludwig-Maximilians-Universität München, Biozentrum, 82152 Planegg-Martinsried, Germany.
authors.forename: Birgit
authors.initials: B
authors.lastname: Rengstl
authors.affiliation: Molekularbiologie der Pflanzen, Ludwig-Maximilians-Universität München, Biozentrum, 82152 Planegg-Martinsried, Germany.
authors.forename: Stefania
authors.identifier: http://orcid.org/0000-0003-0773-8158
authors.initials: S
authors.lastname: Viola
authors.affiliation: Biochemie der Pflanzen, Ruhr-Universität Bochum, 44801 Bochum, Germany.
authors.forename: Marc M
authors.initials: MM
authors.lastname: Nowaczyk
authors.affiliation: Molekularbiologie der Pflanzen, Ludwig-Maximilians-Universität München, Biozentrum, 82152 Planegg-Martinsried, Germany.
authors.forename: Dario
authors.identifier: http://orcid.org/0000-0003-1897-8421
authors.initials: D
authors.lastname: Leister
authors.affiliation: Molekulare Pflanzenwissenschaften, Ludwig-Maximilians-Universität München, Biozentrum, 82152 Planegg-Martinsried, Germany joerg.nickelsen@lrz.uni-muenchen.de.
authors.forename: Jörg
authors.initials: J
authors.lastname: Nickelsen