Localisation and interactions of the Vipp1 protein in cyanobacteria |
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Authors: | Dmitriy Shevela Jianfeng Yu Eva Rupprecht Lu‐Ning Liu Giulia Mastroianni Quan Xue Isabel Llorente‐Garcia Mark C Leake Lutz A Eichacker Dirk Schneider Peter J Nixon Conrad W Mullineaux |
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Institution: | 1. Department of Mathematics and Natural Science, University of Stavanger, , 4036 Stavanger, Norway;2. Department of Life Sciences, Imperial College London, , London, SW7 2AZ UK;3. Institut für Biochemie und Molekularbiologie, ZBMZ, Albert‐Ludwigs‐Universit?t, , 79104 Freiburg, Germany;4. School of Biological and Chemical Sciences, Queen Mary University of London, , London, E1 4NS UK;5. Clarendon Laboratory, Department of Physics, University of Oxford, , Oxford, OX1 3PU UK;6. Department of Physics and Astronomy, University College London, , London, WC1E 6BT UK;7. Biological Physical Sciences Institute (BPSI), Departments of Physics and Biology, University of York, , York, YO105DD UK;8. Institut für Pharmazie und Biochemie, Johannes Gutenberg‐Universit?t Mainz, , 55128 Mainz, Germany |
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Abstract: | The Vipp1 protein is essential in cyanobacteria and chloroplasts for the maintenance of photosynthetic function and thylakoid membrane architecture. To investigate its mode of action we generated strains of the cyanobacteria Synechocystis sp. PCC6803 and Synechococcus sp. PCC7942 in which Vipp1 was tagged with green fluorescent protein at the C‐terminus and expressed from the native chromosomal locus. There was little perturbation of function. Live‐cell fluorescence imaging shows dramatic relocalisation of Vipp1 under high light. Under low light, Vipp1 is predominantly dispersed in the cytoplasm with occasional concentrations at the outer periphery of the thylakoid membranes. High light induces Vipp1 coalescence into localised puncta within minutes, with net relocation of Vipp1 to the vicinity of the cytoplasmic membrane and the thylakoid membranes. Pull‐downs and mass spectrometry identify an extensive collection of proteins that are directly or indirectly associated with Vipp1 only after high‐light exposure. These include not only photosynthetic and stress‐related proteins but also RNA‐processing, translation and protein assembly factors. This suggests that the Vipp1 puncta could be involved in protein assembly. One possibility is that Vipp1 is involved in the formation of stress‐induced localised protein assembly centres, enabling enhanced protein synthesis and delivery to membranes under stress conditions. |
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