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Payne-Dwyer A, Kumar G, Barrett J, Gherman LK, Hodgkinson M, Plevin M, Mackinder L, Leake MC, Schaefer C. Predicting Rubisco-Linker Condensation from Titration in the Dilute Phase. PHYSICAL REVIEW LETTERS 2024; 132:218401. [PMID: 38856270 DOI: 10.1103/physrevlett.132.218401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Accepted: 04/09/2024] [Indexed: 06/11/2024]
Abstract
The condensation of Rubisco holoenzymes and linker proteins into "pyrenoids," a crucial supercharger of photosynthesis in algae, is qualitatively understood in terms of "sticker-and-spacer" theory. We derive semianalytical partition sums for small Rubisco-linker aggregates, which enable the calculation of both dilute-phase titration curves and dimerization diagrams. By fitting the titration curves to surface plasmon resonance and single-molecule fluorescence microscopy data, we extract the molecular properties needed to predict dimerization diagrams. We use these to estimate typical concentrations for condensation, and successfully compare these to microscopy observations.
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Affiliation(s)
- Alex Payne-Dwyer
- School of Physics, Engineering and Technology, University of York, York, YO10 5DD, United Kingdom
| | - Gaurav Kumar
- Department of Biology, University of York, York, YO10 5DD, United Kingdom
- Centre for Novel Agricultural Products (CNAP), Department of Biology, University of York, York, YO10 5DD, United Kingdom
| | - James Barrett
- Department of Biology, University of York, York, YO10 5DD, United Kingdom
- Centre for Novel Agricultural Products (CNAP), Department of Biology, University of York, York, YO10 5DD, United Kingdom
| | - Laura K Gherman
- Department of Biology, University of York, York, YO10 5DD, United Kingdom
- York Structural Biology Laboratory, The University of York; York, YO10 5DD, United Kingdom
| | - Michael Hodgkinson
- Department of Biology, University of York, York, YO10 5DD, United Kingdom
| | - Michael Plevin
- Department of Biology, University of York, York, YO10 5DD, United Kingdom
- York Structural Biology Laboratory, The University of York; York, YO10 5DD, United Kingdom
| | - Luke Mackinder
- Department of Biology, University of York, York, YO10 5DD, United Kingdom
- Centre for Novel Agricultural Products (CNAP), Department of Biology, University of York, York, YO10 5DD, United Kingdom
| | - Mark C Leake
- School of Physics, Engineering and Technology, University of York, York, YO10 5DD, United Kingdom
- Department of Biology, University of York, York, YO10 5DD, United Kingdom
| | - Charley Schaefer
- School of Physics, Engineering and Technology, University of York, York, YO10 5DD, United Kingdom
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Noda S, Akanuma G, Keyamura K, Hishida T. RecN spatially and temporally controls RecA-mediated repair of DNA double-strand breaks. J Biol Chem 2023; 299:105466. [PMID: 37979912 PMCID: PMC10714372 DOI: 10.1016/j.jbc.2023.105466] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Revised: 11/03/2023] [Accepted: 11/06/2023] [Indexed: 11/20/2023] Open
Abstract
RecN, a bacterial structural maintenance of chromosomes-like protein, plays an important role in maintaining genomic integrity by facilitating the repair of DNA double-strand breaks (DSBs). However, how RecN-dependent chromosome dynamics are integrated with DSB repair remains unclear. Here, we investigated the dynamics of RecN in response to DNA damage by inducing RecN from the PBAD promoter at different time points. We found that mitomycin C (MMC)-treated ΔrecN cells exhibited nucleoid fragmentation and reduced cell survival; however, when RecN was induced with arabinose in MMC-exposed ΔrecN cells, it increased a level of cell viability to similar extent as WT cells. Furthermore, in MMC-treated ΔrecN cells, arabinose-induced RecN colocalized with RecA in nucleoid gaps between fragmented nucleoids and restored normal nucleoid structures. These results suggest that the aberrant nucleoid structures observed in MMC-treated ΔrecN cells do not represent catastrophic chromosome disruption but rather an interruption of the RecA-mediated process. Thus, RecN can resume DSB repair by stimulating RecA-mediated homologous recombination, even when chromosome integrity is compromised. Our data demonstrate that RecA-mediated presynapsis and synapsis are spatiotemporally separable, wherein RecN is involved in facilitating both processes presumably by orchestrating the dynamics of both RecA and chromosomes, highlighting the essential role of RecN in the repair of DSBs.
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Affiliation(s)
- Shunsuke Noda
- Department of Molecular Biology, Graduate School of Science, Gakushuin University, Tokyo, Japan
| | - Genki Akanuma
- Department of Molecular Biology, Graduate School of Science, Gakushuin University, Tokyo, Japan
| | - Kenji Keyamura
- Department of Molecular Biology, Graduate School of Science, Gakushuin University, Tokyo, Japan
| | - Takashi Hishida
- Department of Molecular Biology, Graduate School of Science, Gakushuin University, Tokyo, Japan.
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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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