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Localisation and interactions of the V ipp1 protein in cyanobacteria
Author(s) -
Bryan Samantha J.,
Burroughs Nigel J.,
Shevela Dmitriy,
Yu Jianfeng,
Rupprecht Eva,
Liu LuNing,
Mastroianni Giulia,
Xue Quan,
LlorenteGarcia Isabel,
Leake Mark C.,
Eichacker Lutz A.,
Schneider Dirk,
Nixon Peter J.,
Mullineaux Conrad W.
Publication year - 2014
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/mmi.12826
Subject(s) - thylakoid , biology , cytoplasm , cyanobacteria , chloroplast , green fluorescent protein , photosynthesis , microbiology and biotechnology , transport protein , biophysics , membrane , biochemistry , gene , genetics , bacteria
Summary The V ipp1 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 S ynechocystis sp. PCC 6803 and S ynechococcus sp. PCC 7942 in which V ipp1 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 V ipp1 under high light. Under low light, V ipp1 is predominantly dispersed in the cytoplasm with occasional concentrations at the outer periphery of the thylakoid membranes. High light induces V ipp1 coalescence into localised puncta within minutes, with net relocation of V ipp1 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 V ipp1 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 V ipp1 puncta could be involved in protein assembly. One possibility is that V ipp1 is involved in the formation of stress‐induced localised protein assembly centres, enabling enhanced protein synthesis and delivery to membranes under stress conditions.