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Adler L, Lau CS, Shaikh KM, van Maldegem KA, Payne-Dwyer AL, Lefoulon C, Girr P, Atkinson N, Barrett J, Emrich-Mills TZ, Dukic E, Blatt MR, Leake MC, Peltier G, Spetea C, Burlacot A, McCormick AJ, Mackinder LCM, Walker CE. The role of BST4 in the pyrenoid of Chlamydomonas reinhardtii. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.15.545204. [PMID: 38014171 PMCID: PMC10680556 DOI: 10.1101/2023.06.15.545204] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
In many eukaryotic algae, CO2 fixation by Rubisco is enhanced by a CO2-concentrating mechanism, which utilizes a Rubisco-rich organelle called the pyrenoid. The pyrenoid is traversed by a network of thylakoid-membranes called pyrenoid tubules, proposed to deliver CO2. In the model alga Chlamydomonas reinhardtii (Chlamydomonas), the pyrenoid tubules have been proposed to be tethered to the Rubisco matrix by a bestrophin-like transmembrane protein, BST4. Here, we show that BST4 forms a complex that localizes to the pyrenoid tubules. A Chlamydomonas mutant impaired in the accumulation of BST4 (bst4) formed normal pyrenoid tubules and heterologous expression of BST4 in Arabidopsis thaliana did not lead to the incorporation of thylakoids into a reconstituted Rubisco condensate. Chlamydomonas bst4 mutant did not show impaired growth at air level CO2. By quantifying the non-photochemical quenching (NPQ) of chlorophyll fluorescence, we show that bst4 displays a transiently lower thylakoid lumenal pH during dark to light transition compared to control strains. When acclimated to high light, bst4 had sustained higher NPQ and elevated levels of light-induced H2O2 production. We conclude that BST4 is not a tethering protein, but rather is an ion channel involved in lumenal pH regulation possibly by mediating bicarbonate transport across the pyrenoid tubules.
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Affiliation(s)
- Liat Adler
- Institute of Molecular Plant Sciences, School of Biological Sciences, University of Edinburgh, EH9 3BF, United Kingdom
- Centre for Engineering Biology, University of Edinburgh, EH9 3BF, United Kingdom
- Department of Plant Biology, The Carnegie Institution for Science, Stanford, CA, 94305 USA
| | - Chun Sing Lau
- Centre for Novel Agricultural Products (CNAP), Department of Biology, University of York, Heslington, York YO10 5DD, United Kingdom
| | - Kashif M Shaikh
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg 40530, Sweden
| | - Kim A van Maldegem
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg 40530, Sweden
| | - Alex L Payne-Dwyer
- Centre for Novel Agricultural Products (CNAP), Department of Biology, University of York, Heslington, York YO10 5DD, United Kingdom
- School of Physics, Engineering and Technology, University of York, Heslington, York YO10 5DD, United Kingdom
| | - Cecile Lefoulon
- Laboratory of Plant Physiology and Biophysics, Bower Building, University of Glasgow, Glasgow, United Kingdom
| | - Philipp Girr
- Centre for Novel Agricultural Products (CNAP), Department of Biology, University of York, Heslington, York YO10 5DD, United Kingdom
| | - Nicky Atkinson
- Institute of Molecular Plant Sciences, School of Biological Sciences, University of Edinburgh, EH9 3BF, United Kingdom
- Centre for Engineering Biology, University of Edinburgh, EH9 3BF, United Kingdom
| | - James Barrett
- Centre for Novel Agricultural Products (CNAP), Department of Biology, University of York, Heslington, York YO10 5DD, United Kingdom
| | - Tom Z Emrich-Mills
- Centre for Novel Agricultural Products (CNAP), Department of Biology, University of York, Heslington, York YO10 5DD, United Kingdom
| | - Emilija Dukic
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg 40530, Sweden
| | - Michael R Blatt
- Laboratory of Plant Physiology and Biophysics, Bower Building, University of Glasgow, Glasgow, United Kingdom
| | - Mark C Leake
- Centre for Novel Agricultural Products (CNAP), Department of Biology, University of York, Heslington, York YO10 5DD, United Kingdom
- School of Physics, Engineering and Technology, University of York, Heslington, York YO10 5DD, United Kingdom
| | - Gilles Peltier
- Aix-Marseille Université, CEA, CNRS, Institut de Biosciences et Biotechnologies Aix-Marseille, CEA Cadarache, 13108 Saint-Paul-lez-Durance, France
| | - Cornelia Spetea
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg 40530, Sweden
| | - Adrien Burlacot
- Department of Plant Biology, The Carnegie Institution for Science, Stanford, CA, 94305 USA
- Department of Biology, Stanford University, Stanford, CA, 94305, USA
| | - Alistair J McCormick
- Institute of Molecular Plant Sciences, School of Biological Sciences, University of Edinburgh, EH9 3BF, United Kingdom
- Centre for Engineering Biology, University of Edinburgh, EH9 3BF, United Kingdom
| | - Luke C M Mackinder
- Centre for Novel Agricultural Products (CNAP), Department of Biology, University of York, Heslington, York YO10 5DD, United Kingdom
| | - Charlotte E Walker
- Centre for Novel Agricultural Products (CNAP), Department of Biology, University of York, Heslington, York YO10 5DD, United Kingdom
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Single-molecule and super-resolved imaging deciphers membrane behavior of onco-immunogenic CCR5. iScience 2022; 25:105675. [PMID: 36561885 PMCID: PMC9763858 DOI: 10.1016/j.isci.2022.105675] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Revised: 09/20/2022] [Accepted: 11/22/2022] [Indexed: 11/26/2022] Open
Abstract
The ability of tumors to establish a pro-tumorigenic microenvironment is an important point of investigation in the search for new therapeutics. Tumors form microenvironments in part by the "education" of immune cells attracted via chemotactic axes such as that of CCR5-CCL5. Further, CCR5 upregulation by cancer cells, coupled with its association with pro-tumorigenic features such as drug resistance and metastasis, has suggested CCR5 as a therapeutic target. However, with several conformational "pools" being reported, phenotypic investigations must be capable of unveiling conformational heterogeneity. Addressing this challenge, we performed super-resolution structured illumination microscopy (SIM) and single molecule partially TIRF-coupled HILO (PaTCH) microscopy of CCR5 in fixed cells. SIM data revealed a non-random spatial distribution of CCR5 assemblies, while Intensity-tracking of CCR5 assemblies from PaTCH images indicated dimeric sub-units independent of CCL5 perturbation. These biophysical methods can provide important insights into the structure and function of onco-immunogenic receptors and many other biomolecules.
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Payne-Dwyer AL, Syeda AH, Shepherd JW, Frame L, Leake MC. RecA and RecB: probing complexes of DNA repair proteins with mitomycin C in live Escherichia coli with single-molecule sensitivity. JOURNAL OF THE ROYAL SOCIETY, INTERFACE 2022; 19:20220437. [PMID: 35946163 PMCID: PMC9363994 DOI: 10.1098/rsif.2022.0437] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The RecA protein and RecBCD complex are key bacterial components for the maintenance and repair of DNA. RecBCD is a helicase-nuclease that uses homologous recombination to resolve double-stranded DNA breaks. It also facilitates coating of single-stranded DNA with RecA to form RecA filaments, a vital step in the double-stranded break DNA repair pathway. However, questions remain about the mechanistic roles of RecA and RecBCD in live cells. Here, we use millisecond super-resolved fluorescence microscopy to pinpoint the spatial localization of fluorescent reporters of RecA or RecB at physiological levels of expression in individual live Escherichia coli cells. By introducing the DNA cross-linker mitomycin C, we induce DNA damage and quantify the resulting steady state changes in stoichiometry, cellular protein copy number and molecular mobilities of RecA and RecB. We find that both proteins accumulate in molecular hotspots to effect repair, resulting in RecA stoichiometries equivalent to several hundred molecules that assemble largely in dimeric subunits before DNA damage, but form periodic subunits of approximately 3-4 molecules within mature filaments of several thousand molecules. Unexpectedly, we find that the physiologically predominant forms of RecB are not only rapidly diffusing monomers, but slowly diffusing dimers.
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Affiliation(s)
- Alex L Payne-Dwyer
- Department of Physics, University of York, York YO10 5DD, UK.,Department of Biology, University of York, York YO10 5DD, UK
| | - Aisha H Syeda
- Department of Physics, University of York, York YO10 5DD, UK.,Department of Biology, University of York, York YO10 5DD, UK
| | - Jack W Shepherd
- Department of Physics, University of York, York YO10 5DD, UK.,Department of Biology, University of York, York YO10 5DD, UK
| | - Lewis Frame
- School of Natural Sciences, University of York, York YO10 5DD, UK
| | - Mark C Leake
- Department of Physics, University of York, York YO10 5DD, UK.,Department of Biology, University of York, York YO10 5DD, UK
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