1
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Kaja E, Vijande D, Kowalczyk J, Michalak M, Gapiński J, Kobras C, Rolfe P, Stracy M. Comparing Mfd- and UvrD-dependent models of transcription coupled DNA repair in live Escherichia coli using single-molecule tracking. DNA Repair (Amst) 2024; 137:103665. [PMID: 38513450 DOI: 10.1016/j.dnarep.2024.103665] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Revised: 02/16/2024] [Accepted: 03/01/2024] [Indexed: 03/23/2024]
Abstract
During transcription-coupled DNA repair (TCR) the detection of DNA damage and initiation of nucleotide excision repair (NER) is performed by translocating RNA polymerases (RNAP), which are arrested upon encountering bulky DNA lesions. Two opposing models of the subsequent steps of TCR in bacteria exist. In the first model, stalled RNAPs are removed from the damage site by recruitment of Mfd which dislodges RNAP by pushing it forwards before recruitment of UvrA and UvrB. In the second model, UvrD helicase backtracks RNAP from the lesion site. Recent studies have proposed that both UvrD and UvrA continuously associate with RNAP before damage occurs, which forms the primary damage sensor for NER. To test these two models of TCR in living E. coli, we applied super-resolution microscopy (PALM) combined with single particle tracking to directly measure the mobility and recruitment of Mfd, UvrD, UvrA, and UvrB to DNA during ultraviolet-induced DNA damage. The intracellular mobilities of NER proteins in the absence of DNA damage showed that most UvrA molecules could in principle be complexed with RNAP, however, this was not the case for UvrD. Upon DNA damage, Mfd recruitment to DNA was independent of the presence of UvrA, in agreement with its role upstream of this protein in the TCR pathway. In contrast, UvrD recruitment to DNA was strongly dependent on the presence of UvrA. Inhibiting transcription with rifampicin abolished Mfd DNA-recruitment following DNA damage, whereas significant UvrD, UvrA, and UvrB recruitment remained, consistent with a UvrD and UvrA performing their NER functions independently of transcribing RNAP. Together, although we find that up to ∼8 UvrD-RNAP-UvrA complexes per cell could potentially form in the absence of DNA damage, our live-cell data is not consistent with this complex being the primary DNA damage sensor for NER.
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Affiliation(s)
- Elżbieta Kaja
- Molecular Biophysics Division, Faculty of Physics, Adam Mickiewicz University, Uniwersytetu Poznańskiego 2, Poznan 61-614, Poland; Chair and Department of Medical Chemistry and Laboratory Medicine, Poznan University of Medical Sciences, Rokietnicka 8, 60-806 Poznan, Poland.
| | - Donata Vijande
- Molecular Biophysics Division, Faculty of Physics, Adam Mickiewicz University, Uniwersytetu Poznańskiego 2, Poznan 61-614, Poland
| | - Justyna Kowalczyk
- Molecular Biophysics Division, Faculty of Physics, Adam Mickiewicz University, Uniwersytetu Poznańskiego 2, Poznan 61-614, Poland
| | - Michał Michalak
- Molecular Biophysics Division, Faculty of Physics, Adam Mickiewicz University, Uniwersytetu Poznańskiego 2, Poznan 61-614, Poland
| | - Jacek Gapiński
- Molecular Biophysics Division, Faculty of Physics, Adam Mickiewicz University, Uniwersytetu Poznańskiego 2, Poznan 61-614, Poland
| | - Carolin Kobras
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
| | - Philippa Rolfe
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
| | - Mathew Stracy
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK.
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2
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Mitra A, Loseva E, Peterman EJG. IFT cargo and motors associate sequentially with IFT trains to enter cilia of C. elegans. Nat Commun 2024; 15:3456. [PMID: 38658528 PMCID: PMC11043347 DOI: 10.1038/s41467-024-47807-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2023] [Accepted: 04/12/2024] [Indexed: 04/26/2024] Open
Abstract
Intraflagellar transport (IFT) orchestrates entry of proteins into primary cilia. At the ciliary base, assembled IFT trains, driven by kinesin-2 motors, can transport cargo proteins into the cilium, across the crowded transition zone. How trains assemble at the base and how proteins associate with them is far from understood. Here, we use single-molecule imaging in the cilia of C. elegans chemosensory neurons to directly visualize the entry of kinesin-2 motors, kinesin-II and OSM-3, as well as anterograde cargo proteins, IFT dynein and tubulin. Single-particle tracking shows that IFT components associate with trains sequentially, both in time and space. Super-resolution maps of IFT components in wild-type and mutant worms reveal ciliary ultrastructure and show that kinesin-II is essential for axonemal organization. Finally, imaging cilia lacking kinesin-II and/or transition zone function uncovers the interplay of kinesin-II and OSM-3 in driving efficient transport of IFT trains across the transition zone.
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Affiliation(s)
- Aniruddha Mitra
- Department of Physics and Astronomy and LaserLaB, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
- Cell Biology, Neurobiology and Biophysics, Department of Biology, Faculty of Science, Utrecht University, Utrecht, The Netherlands
| | - Elizaveta Loseva
- Department of Physics and Astronomy and LaserLaB, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Erwin J G Peterman
- Department of Physics and Astronomy and LaserLaB, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands.
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3
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Irmisch P, Mogila I, Samatanga B, Tamulaitis G, Seidel R. Retention of the RNA ends provides the molecular memory for maintaining the activation of the Csm complex. Nucleic Acids Res 2024; 52:3896-3910. [PMID: 38340341 DOI: 10.1093/nar/gkae080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Revised: 01/23/2024] [Accepted: 02/07/2024] [Indexed: 02/12/2024] Open
Abstract
The type III CRISPR-Cas effector complex Csm functions as a molecular Swiss army knife that provides multilevel defense against foreign nucleic acids. The coordinated action of three catalytic activities of the Csm complex enables simultaneous degradation of the invader's RNA transcripts, destruction of the template DNA and synthesis of signaling molecules (cyclic oligoadenylates cAn) that activate auxiliary proteins to reinforce CRISPR-Cas defense. Here, we employed single-molecule techniques to connect the kinetics of RNA binding, dissociation, and DNA hydrolysis by the Csm complex from Streptococcus thermophilus. Although single-stranded RNA is cleaved rapidly (within seconds), dual-color FCS experiments and single-molecule TIRF microscopy revealed that Csm remains bound to terminal RNA cleavage products with a half-life of over 1 hour while releasing the internal RNA fragments quickly. Using a continuous fluorescent DNA degradation assay, we observed that RNA-regulated single-stranded DNase activity decreases on a similar timescale. These findings suggest that after fast target RNA cleavage the terminal RNA cleavage products stay bound within the Csm complex, keeping the Cas10 subunit activated for DNA destruction. Additionally, we demonstrate that during Cas10 activation, the complex remains capable of RNA turnover, i.e. of ongoing degradation of target RNA.
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Affiliation(s)
- Patrick Irmisch
- Peter Debye Institute for Soft Matter Physics, University of Leipzig, Leipzig 04103, Germany
| | - Irmantas Mogila
- Institute of Biotechnology, Life Sciences Center, Vilnius University, Vilnius 10257, Lithuania
| | - Brighton Samatanga
- Peter Debye Institute for Soft Matter Physics, University of Leipzig, Leipzig 04103, Germany
| | - Gintautas Tamulaitis
- Institute of Biotechnology, Life Sciences Center, Vilnius University, Vilnius 10257, Lithuania
| | - Ralf Seidel
- Peter Debye Institute for Soft Matter Physics, University of Leipzig, Leipzig 04103, Germany
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4
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van der Sleen L, Stevens JA, Marrink SJ, Poolman B, Tych K. Probing the stability and interdomain interactions in the ABC transporter OpuA using single-molecule optical tweezers. Cell Rep 2024; 43:114110. [PMID: 38607912 DOI: 10.1016/j.celrep.2024.114110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Revised: 12/11/2023] [Accepted: 03/28/2024] [Indexed: 04/14/2024] Open
Abstract
Transmembrane transporter proteins are essential for maintaining cellular homeostasis and, as such, are key drug targets. Many transmembrane transporter proteins are known to undergo large structural rearrangements during their functional cycles. Despite the wealth of detailed structural and functional data available for these systems, our understanding of their dynamics and, consequently, how they function is generally limited. We introduce an innovative approach that enables us to directly measure the dynamics and stability of interdomain interactions of transmembrane proteins using optical tweezers. Focusing on the osmoregulatory ATP-binding cassette transporter OpuA from Lactococcus lactis, we examine the mechanical properties and potential interactions of its substrate-binding domains. Our measurements are performed in lipid nanodiscs, providing a native-mimicking environment for the transmembrane protein. The technique provides high spatial and temporal resolution and allows us to study the functionally relevant motions and interdomain interactions of individual transmembrane transporter proteins in real time in a lipid bilayer.
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Affiliation(s)
- Lyan van der Sleen
- Department of Biochemistry, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 4, 9747 AG Groningen, the Netherlands
| | - Jan A Stevens
- Molecular Dynamics Group, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 7, 9747 AG Groningen, the Netherlands
| | - Siewert J Marrink
- Molecular Dynamics Group, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 7, 9747 AG Groningen, the Netherlands
| | - Bert Poolman
- Department of Biochemistry, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 4, 9747 AG Groningen, the Netherlands.
| | - Kasia Tych
- Chemical Biology Group, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 7, 9747 AG Groningen, the Netherlands.
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5
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Iinuma R, Chen X, Masubuchi T, Ueda T, Tadakuma H. Size-Selective Capturing of Exosomes Using DNA Tripods. J Am Chem Soc 2024; 146:10293-10298. [PMID: 38569597 PMCID: PMC11027911 DOI: 10.1021/jacs.3c11067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2023] [Revised: 03/09/2024] [Accepted: 03/12/2024] [Indexed: 04/05/2024]
Abstract
Fractionating and characterizing target samples are fundamental to the analysis of biomolecules. Extracellular vesicles (EVs), containing information regarding the cellular birthplace, are promising targets for biology and medicine. However, the requirement for multiple-step purification in conventional methods hinders analysis of small samples. Here, we apply a DNA origami tripod with a defined aperture of binders (e.g., antibodies against EV biomarkers), which allows us to capture the target molecule. Using exosomes as a model, we show that our tripod nanodevice can capture a specific size range of EVs with cognate biomarkers from a broad distribution of crude EV mixtures. We further demonstrate that the size of captured EVs can be controlled by changing the aperture of the tripods. This simultaneous selection with the size and biomarker approach should simplify the EV purification process and contribute to the precise analysis of target biomolecules from small samples.
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Affiliation(s)
- Ryosuke Iinuma
- Graduate
School of Frontier Science, The University
of Tokyo, Chiba 277-8562, Japan
- JSR
Corporation, Ibaraki, 305-0841, Japan
| | - Xiaoxia Chen
- School
of Life Science and Technology, ShanghaiTech
University, Shanghai 201210, People’s Republic of China
| | - Takeya Masubuchi
- Graduate
School of Frontier Science, The University
of Tokyo, Chiba 277-8562, Japan
- Department
of Cell and Developmental Biology, School of Biological Sciences, University of California San Diego, La Jolla, California 92093, United States
| | - Takuya Ueda
- Graduate
School of Frontier Science, The University
of Tokyo, Chiba 277-8562, Japan
- Graduate
School of Science and Engineering, Waseda
University, Tokyo 162-8480, Japan
| | - Hisashi Tadakuma
- Graduate
School of Frontier Science, The University
of Tokyo, Chiba 277-8562, Japan
- School
of Life Science and Technology, ShanghaiTech
University, Shanghai 201210, People’s Republic of China
- Gene Editing
Center, School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, People’s Republic
of China
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6
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Khan S, Molloy JE, Puhl H, Schulman H, Vogel SS. Real-time single-molecule imaging of CaMKII-calmodulin interactions. Biophys J 2024; 123:824-838. [PMID: 38414237 DOI: 10.1016/j.bpj.2024.02.021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Revised: 12/20/2023] [Accepted: 02/22/2024] [Indexed: 02/29/2024] Open
Abstract
The binding of calcium/calmodulin (CAM) to calcium/calmodulin-dependent protein kinase II (CaMKII) initiates an ATP-driven cascade that triggers CaMKII autophosphorylation. The autophosphorylation in turn increases the CaMKII affinity for CAM. Here, we studied the ATP dependence of CAM association with the actin-binding CaMKIIβ isoform using single-molecule total internal reflection fluorescence microscopy. Rhodamine-CAM associations/dissociations to surface-immobilized Venus-CaMKIIβ were resolved with 0.5 s resolution from video records, batch-processed with a custom algorithm. CAM occupancy was determined simultaneously with spot-photobleaching measurement of CaMKII holoenzyme stoichiometry. We show the ATP-dependent increase of the CAM association requires dimer formation for both the α and β isoforms. The study of mutant β holoenzymes revealed that the ATP-dependent increase in CAM affinity results in two distinct states. The phosphorylation-defective (T287.306-307A) holoenzyme resides only in the low-affinity state. CAM association is further reduced in the T287A holoenzyme relative to T287.306-307A. In the absence of ATP, the affinity of CAM for the T287.306-307A mutant and the wild-type monomer are comparable. The affinity of the ATP-binding impaired (K43R) mutant is even weaker. In ATP, the K43R holoenzyme resides in the low-affinity state. The phosphomimetic mutant (T287D) resides only in a 1000-fold higher-affinity state, with mean CAM occupancy of more than half of the 14-mer holoenzyme stoichiometry in picomolar CAM. ATP promotes T287D holoenzyme disassembly but does not elevate CAM occupancy. Single Poisson distributions characterized the ATP-dependent CAM occupancy of mutant holoenzymes. In contrast, the CAM occupancy of the wild-type population had a two-state distribution with both low- and high-affinity states represented. The low-affinity state was the dominant state, a result different from published in vitro assays. Differences in assay conditions can alter the balance between activating and inhibitory autophosphorylation. Bound ATP could be sufficient for CaMKII structural function, while antagonistic autophosphorylations may tune CaMKII kinase-regulated action-potential frequency decoding in vivo.
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Affiliation(s)
- Shahid Khan
- Molecular Biology Consortium at Lawrence Berkeley National Laboratory, Berkeley, California.
| | | | - Henry Puhl
- Laboratory of Biophotonics and Quantum Biology, National Institutes on Alcohol, Abuse and Alcoholism, National Institutes of Health, Rockville, Maryland
| | - Howard Schulman
- Panorama Research Institute, Sunnyvale, California; Stanford University School of Medicine, Stanford, California
| | - Steven S Vogel
- Laboratory of Biophotonics and Quantum Biology, National Institutes on Alcohol, Abuse and Alcoholism, National Institutes of Health, Rockville, Maryland
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7
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Hwang DW, Maekiniemi A, Singer RH, Sato H. Real-time single-molecule imaging of transcriptional regulatory networks in living cells. Nat Rev Genet 2024; 25:272-285. [PMID: 38195868 DOI: 10.1038/s41576-023-00684-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/27/2023] [Indexed: 01/11/2024]
Abstract
Gene regulatory networks drive the specific transcriptional programmes responsible for the diversification of cell types during the development of multicellular organisms. Although our knowledge of the genes involved in these dynamic networks has expanded rapidly, our understanding of how transcription is spatiotemporally regulated at the molecular level over a wide range of timescales in the small volume of the nucleus remains limited. Over the past few decades, advances in the field of single-molecule fluorescence imaging have enabled real-time behaviours of individual transcriptional components to be measured in living cells and organisms. These efforts are now shedding light on the dynamic mechanisms of transcription, revealing not only the temporal rules but also the spatial coordination of underlying molecular interactions during various biological events.
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Affiliation(s)
- Dong-Woo Hwang
- Department of Cell Biology, Albert Einstein College of Medicine, New York, NY, USA
| | - Anna Maekiniemi
- Department of Cell Biology, Albert Einstein College of Medicine, New York, NY, USA
| | - Robert H Singer
- Department of Cell Biology, Albert Einstein College of Medicine, New York, NY, USA
| | - Hanae Sato
- Department of Cell Biology, Albert Einstein College of Medicine, New York, NY, USA.
- Nano Life Science Institute (WPI-Nano LSI), Kanazawa University, Kakuma-machi, Kanazawa, Japan.
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8
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Hatton D, Cha J, Riggs S, Harrison PJ, Thiyagalingam J, Clare DK, Morris KL. EMinsight: a tool to capture cryoEM microscope configuration and experimental outcomes for analysis and deposition. Acta Crystallogr D Struct Biol 2024; 80:259-269. [PMID: 38573522 PMCID: PMC10994178 DOI: 10.1107/s2059798324001578] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Accepted: 02/16/2024] [Indexed: 04/05/2024] Open
Abstract
The widespread adoption of cryoEM technologies for structural biology has pushed the discipline to new frontiers. A significant worldwide effort has refined the single-particle analysis (SPA) workflow into a reasonably standardized procedure. Significant investments of development time have been made, particularly in sample preparation, microscope data-collection efficiency, pipeline analyses and data archiving. The widespread adoption of specific commercial microscopes, software for controlling them and best practices developed at facilities worldwide has also begun to establish a degree of standardization to data structures coming from the SPA workflow. There is opportunity to capitalize on this moment in the maturation of the field, to capture metadata from SPA experiments and correlate the metadata with experimental outcomes, which is presented here in a set of programs called EMinsight. This tool aims to prototype the framework and types of analyses that could lead to new insights into optimal microscope configurations as well as to define methods for metadata capture to assist with the archiving of cryoEM SPA data. It is also envisaged that this tool will be useful to microscope operators and facilities looking to rapidly generate reports on SPA data-collection and screening sessions.
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Affiliation(s)
- Daniel Hatton
- Data Analysis, Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 0DE, United Kingdom
| | - Jaehoon Cha
- Scientific Computing, Science and Technology Facilities Council, Harwell Science and Innovation Campus, Didcot OX11 0QX, United Kingdom
| | - Stephen Riggs
- Data Analysis, Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 0DE, United Kingdom
| | - Peter J. Harrison
- Electron Bio-Imaging Centre (eBIC), Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 0DE, United Kingdom
| | - Jeyan Thiyagalingam
- Scientific Computing, Science and Technology Facilities Council, Harwell Science and Innovation Campus, Didcot OX11 0QX, United Kingdom
| | - Daniel K. Clare
- Electron Bio-Imaging Centre (eBIC), Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 0DE, United Kingdom
| | - Kyle L. Morris
- Electron Microscopy Data Bank, European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Genome Campus, Hinxton, Cambridge CB10 1SD, United Kingdom
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9
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Unterauer EM, Shetab Boushehri S, Jevdokimenko K, Masullo LA, Ganji M, Sograte-Idrissi S, Kowalewski R, Strauss S, Reinhardt SCM, Perovic A, Marr C, Opazo F, Fornasiero EF, Jungmann R. Spatial proteomics in neurons at single-protein resolution. Cell 2024; 187:1785-1800.e16. [PMID: 38552614 DOI: 10.1016/j.cell.2024.02.045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Revised: 11/28/2023] [Accepted: 02/29/2024] [Indexed: 04/02/2024]
Abstract
To understand biological processes, it is necessary to reveal the molecular heterogeneity of cells by gaining access to the location and interaction of all biomolecules. Significant advances were achieved by super-resolution microscopy, but such methods are still far from reaching the multiplexing capacity of proteomics. Here, we introduce secondary label-based unlimited multiplexed DNA-PAINT (SUM-PAINT), a high-throughput imaging method that is capable of achieving virtually unlimited multiplexing at better than 15 nm resolution. Using SUM-PAINT, we generated 30-plex single-molecule resolved datasets in neurons and adapted omics-inspired analysis for data exploration. This allowed us to reveal the complexity of synaptic heterogeneity, leading to the discovery of a distinct synapse type. We not only provide a resource for researchers, but also an integrated acquisition and analysis workflow for comprehensive spatial proteomics at single-protein resolution.
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Affiliation(s)
- Eduard M Unterauer
- Max Planck Institute of Biochemistry, Planegg, Germany; Faculty of Physics and Center for NanoScience, Ludwig-Maximilians-Universität, Munich, Germany
| | - Sayedali Shetab Boushehri
- Institute of AI for Health, Helmholtz Zentrum München - German Research Center for Environmental Health, Neuherberg, Germany; Data & Analytics, Roche Pharma Research and Early Development, Roche Innovation Center Munich, Munich, Germany; Department of Mathematics, Technical University of Munich, Munich, Germany
| | - Kristina Jevdokimenko
- Institute of Neuro- and Sensory Physiology, University Medical Center Göttingen, Göttingen, Germany
| | | | - Mahipal Ganji
- Max Planck Institute of Biochemistry, Planegg, Germany; Department of Biochemistry, Indian Institute of Science, Bangalore, India
| | - Shama Sograte-Idrissi
- Institute of Neuro- and Sensory Physiology, University Medical Center Göttingen, Göttingen, Germany; Center for Biostructural Imaging of Neurodegeneration, University Medical Center Göttingen, Göttingen, Germany
| | - Rafal Kowalewski
- Max Planck Institute of Biochemistry, Planegg, Germany; Faculty of Physics and Center for NanoScience, Ludwig-Maximilians-Universität, Munich, Germany
| | - Sebastian Strauss
- Max Planck Institute of Biochemistry, Planegg, Germany; Faculty of Physics and Center for NanoScience, Ludwig-Maximilians-Universität, Munich, Germany
| | - Susanne C M Reinhardt
- Max Planck Institute of Biochemistry, Planegg, Germany; Faculty of Physics and Center for NanoScience, Ludwig-Maximilians-Universität, Munich, Germany
| | - Ana Perovic
- Max Planck Institute of Biochemistry, Planegg, Germany
| | - Carsten Marr
- Institute of AI for Health, Helmholtz Zentrum München - German Research Center for Environmental Health, Neuherberg, Germany; Department of Mathematics, Technical University of Munich, Munich, Germany
| | - Felipe Opazo
- Institute of Neuro- and Sensory Physiology, University Medical Center Göttingen, Göttingen, Germany; Center for Biostructural Imaging of Neurodegeneration, University Medical Center Göttingen, Göttingen, Germany; NanoTag Biotechnologies GmbH, Göttingen, Germany
| | - Eugenio F Fornasiero
- Institute of Neuro- and Sensory Physiology, University Medical Center Göttingen, Göttingen, Germany; Department of Life Sciences, University of Trieste, Trieste, Italy.
| | - Ralf Jungmann
- Max Planck Institute of Biochemistry, Planegg, Germany; Faculty of Physics and Center for NanoScience, Ludwig-Maximilians-Universität, Munich, Germany.
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10
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Jo MH, Meneses P, Yang O, Carcamo CC, Pangeni S, Ha T. Determination of single-molecule loading rate during mechanotransduction in cell adhesion. Science 2024; 383:1374-1379. [PMID: 38513010 PMCID: PMC10977658 DOI: 10.1126/science.adk6921] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Accepted: 02/19/2024] [Indexed: 03/23/2024]
Abstract
Cells connect with their environment through surface receptors and use physical tension in receptor-ligand bonds for various cellular processes. Single-molecule techniques have revealed bond strength by measuring "rupture force," but it has long been recognized that rupture force is dependent on loading rate-how quickly force is ramped up. Thus, the physiological loading rate needs to be measured to reveal the mechanical strength of individual bonds in their functional context. We have developed an overstretching tension sensor (OTS) to allow more accurate force measurement in physiological conditions with single-molecule detection sensitivity even in mechanically active regions. We used serially connected OTSs to show that the integrin loading rate ranged from 0.5 to 4 piconewtons per second and was about three times higher in leukocytes than in epithelial cells.
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Affiliation(s)
- Myung Hyun Jo
- Program in Cellular and Molecular Medicine, Boston Children’s Hospital, Boston, MA 02115, USA
- Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Paul Meneses
- Program in Cellular and Molecular Medicine, Boston Children’s Hospital, Boston, MA 02115, USA
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Olivia Yang
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Claudia C. Carcamo
- Program in Cellular and Molecular Medicine, Boston Children’s Hospital, Boston, MA 02115, USA
- Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Sushil Pangeni
- Program in Cellular and Molecular Medicine, Boston Children’s Hospital, Boston, MA 02115, USA
- Department of Biophysics, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Taekjip Ha
- Program in Cellular and Molecular Medicine, Boston Children’s Hospital, Boston, MA 02115, USA
- Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University, Baltimore, MD 21205, USA
- Department of Biophysics, Johns Hopkins University, Baltimore, MD 21205, USA
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11
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Zhang X, Taniguchi R, Nagao R, Tomo T, Noguchi T, Ye S, Shibata Y. Access to the Antenna System of Photosystem I via Single-Molecule Excitation-Emission Spectroscopy. J Phys Chem B 2024; 128:2664-2674. [PMID: 38456814 DOI: 10.1021/acs.jpcb.3c07789] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/09/2024]
Abstract
In the development of single-molecule spectroscopy, the simultaneous detection of the excitation and emission spectra has been limited. The fluorescence excitation spectrum based on background-free signals is compatible with the fluorescence-emission-based detection of single molecules and can provide insight into the variations in the input energy of the different terminal emitters. Here, we implement single-molecule excitation-emission spectroscopy (SMEES) for photosystem I (PSI) via a cryogenic optical microscope. To this end, we extended our line-focus-based excitation-spectral microscope system to the cryogenic temperature-compatible version. PSI is one of the two photosystems embedded in the thylakoid membrane in oxygen-free photosynthetic organisms. PSI plays an essential role in electron transfer in the photosynthesis reaction. PSIs of many organisms contain a few red-shifted chlorophylls (Chls) with much lower excitation energies than ordinary antenna Chls. The fluorescence emission spectrum originates primarily from the red-shifted Chls, whereas the excitation spectrum is sensitive to the antenna Chls that are upstream of red-shifted Chls. Using SMEES, we obtained the inclining two-dimensional excitation-emission matrix (2D-EEM) of PSI particles isolated from a cyanobacterium, Thermosynechococcus vestitus (equivalent to elongatus), at about 80 K. Interestingly, by decomposing the inclining 2D-EEMs within time course observation, we found prominent variations in the excitation spectra of the red-shifted Chl pools with different emission wavelengths, strongly indicating the variable excitation energy transfer (EET) pathway from the antenna to the terminal emitting pools. SMEES helps us to directly gain information about the antenna system, which is fundamental to depicting the EET within pigment-protein complexes.
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Affiliation(s)
- Xianjun Zhang
- Department of Chemistry, Graduate School of Sciences, Tohoku University, Sendai 980-8578, Japan
- Division for Interdisciplinary Advanced Research and Education, Tohoku University, Sendai 980-8578, Japan
| | - Rin Taniguchi
- Department of Chemistry, Graduate School of Sciences, Tohoku University, Sendai 980-8578, Japan
| | - Ryo Nagao
- Faculty of Agriculture, Shizuoka University, Shizuoka 422-8529, Japan
| | - Tatsuya Tomo
- Department of Physics, Graduate School of Sciences, Tokyo University of Science, Tokyo 162-8601, Japan
| | - Takumi Noguchi
- Graduate School of Science, Nagoya University, Nagoya 464-8602, Japan
| | - Shen Ye
- Department of Chemistry, Graduate School of Sciences, Tohoku University, Sendai 980-8578, Japan
| | - Yutaka Shibata
- Department of Chemistry, Graduate School of Sciences, Tohoku University, Sendai 980-8578, Japan
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12
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Ao Y, Grover JR, Gifford L, Han Y, Zhong G, Katte R, Li W, Bhattacharjee R, Zhang B, Sauve S, Qin W, Ghimire D, Haque MA, Arthos J, Moradi M, Mothes W, Lemke EA, Kwong PD, Melikyan GB, Lu M. Bioorthogonal click labeling of an amber-free HIV-1 provirus for in-virus single molecule imaging. Cell Chem Biol 2024; 31:487-501.e7. [PMID: 38232732 PMCID: PMC10960674 DOI: 10.1016/j.chembiol.2023.12.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Revised: 10/13/2023] [Accepted: 12/21/2023] [Indexed: 01/19/2024]
Abstract
Structural dynamics of human immunodeficiency virus 1 (HIV-1) envelope (Env) glycoprotein mediate cell entry and facilitate immune evasion. Single-molecule FRET using peptides for Env labeling revealed structural dynamics of Env, but peptide use risks potential effects on structural integrity/dynamics. While incorporating noncanonical amino acids (ncAAs) into Env by amber stop-codon suppression, followed by click chemistry, offers a minimally invasive approach, this has proved to be technically challenging for HIV-1. Here, we develope an intact amber-free HIV-1 system that overcomes hurdles of preexisting viral amber codons. We achieved dual-ncAA incorporation into Env on amber-free virions, enabling single-molecule Förster resonance energy transfer (smFRET) studies of click-labeled Env that validated the previous peptide-based labeling approaches by confirming the intrinsic propensity of Env to dynamically sample multiple conformational states. Amber-free click-labeled Env also enabled real-time tracking of single virion internalization and trafficking in cells. Our system thus permits in-virus bioorthogonal labeling of proteins, compatible with studies of virus entry, trafficking, and egress from cells.
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Affiliation(s)
- Yuanyun Ao
- Department of Cellular and Molecular Biology, School of Medicine, University of Texas at Tyler Health Science Center, Tyler, TX 75708, USA
| | - Jonathan R Grover
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Levi Gifford
- Department of Pediatrics, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Yang Han
- Department of Cellular and Molecular Biology, School of Medicine, University of Texas at Tyler Health Science Center, Tyler, TX 75708, USA
| | - Guohua Zhong
- Department of Cellular and Molecular Biology, School of Medicine, University of Texas at Tyler Health Science Center, Tyler, TX 75708, USA
| | - Revansiddha Katte
- Department of Cellular and Molecular Biology, School of Medicine, University of Texas at Tyler Health Science Center, Tyler, TX 75708, USA
| | - Wenwei Li
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Rajanya Bhattacharjee
- Biocentre, Departments of Biology and Chemistry, Johannes Gutenberg-University Mainz, Hanns-Dieter-Hüsch-Weg 17, 55128 Mainz, Germany; International PhD Program of the Institute of Molecular Biology, Hanns-Dieter-Hüsch-Weg 17, 55128 Mainz, Germany
| | - Baoshan Zhang
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Stephanie Sauve
- Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, AR 72701, USA
| | - Wenyi Qin
- Department of Cellular and Molecular Biology, School of Medicine, University of Texas at Tyler Health Science Center, Tyler, TX 75708, USA
| | - Dibya Ghimire
- Department of Cellular and Molecular Biology, School of Medicine, University of Texas at Tyler Health Science Center, Tyler, TX 75708, USA
| | - Md Anzarul Haque
- Department of Cellular and Molecular Biology, School of Medicine, University of Texas at Tyler Health Science Center, Tyler, TX 75708, USA
| | - James Arthos
- Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Mahmoud Moradi
- Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, AR 72701, USA
| | - Walther Mothes
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Edward A Lemke
- Biocentre, Departments of Biology and Chemistry, Johannes Gutenberg-University Mainz, Hanns-Dieter-Hüsch-Weg 17, 55128 Mainz, Germany; Institute of Molecular Biology, Ackermannweg 4, 55128 Mainz, Germany
| | - Peter D Kwong
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Gregory B Melikyan
- Department of Pediatrics, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Maolin Lu
- Department of Cellular and Molecular Biology, School of Medicine, University of Texas at Tyler Health Science Center, Tyler, TX 75708, USA.
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13
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Yan D, Xue J, Xiao J, Lyu Z, Yang X. Protocol for single-molecule labeling and tracking of bacterial cell division proteins. STAR Protoc 2024; 5:102766. [PMID: 38085639 PMCID: PMC10733747 DOI: 10.1016/j.xpro.2023.102766] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Revised: 10/11/2023] [Accepted: 11/21/2023] [Indexed: 12/24/2023] Open
Abstract
Here, we present a protocol for labeling and tracking individual molecules, particularly cell division proteins in live bacterial cells. The protocol encompasses strain construction, single-molecule imaging, trajectory segmentation, and motion property analysis. The protocol enables the identification of distinctive motion states associated with different cell division proteins. Subsequent assessments of the dynamic behaviors of these proteins provide insights into their activities and interactions at the septum during cell division. For complete details on the use and execution of this protocol, please refer to Yang et al. (2021),1 Lyu et al. (2022),2 and Mahone et al. (2024).3.
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Affiliation(s)
- Di Yan
- School of Basic Medical Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230026, China
| | - Jinchan Xue
- School of Basic Medical Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230026, China
| | - Jie Xiao
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA.
| | - Zhixin Lyu
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA.
| | - Xinxing Yang
- School of Basic Medical Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230026, China.
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14
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Dukhno O, Ghosh S, Greiner V, Bou S, Godet J, Muhr V, Buchner M, Hirsch T, Mély Y, Przybilla F. Targeted Single Particle Tracking with Upconverting Nanoparticles. ACS Appl Mater Interfaces 2024; 16:11217-11227. [PMID: 38386424 DOI: 10.1021/acsami.3c17116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/24/2024]
Abstract
Single particle tracking (SPT) is a powerful technique for real-time microscopic visualization of the movement of individual biomolecules within or on the surface of living cells. However, SPT often suffers from the suboptimal performance of the photon-emitting labels used to tag the biomolecules of interest. For example, fluorescent dyes have poor photostability, while quantum dots suffer from blinking that hampers track acquisition and interpretation. Upconverting nanoparticles (UCNPs) have recently emerged as a promising anti-Stokes luminescent label for SPT. In this work, we demonstrated targeted SPT using UCNPs. For this, we synthesized 30 nm diameter doped UCNPs and coated them with amphiphilic polymers decorated with polyethylene glycol chains to make them water-dispersible and minimize their nonspecific interactions with cells. Coated UCNPs highly homogeneous in brightness (as confirmed by a single particle investigation) were functionalized by immunoglobulin E (IgE) using a biotin-streptavidin strategy. Using these IgE-UCNP SPT labels, we tracked high-affinity IgE receptors (FcεRI) on the membrane of living RBL-2H3 mast cells at 37 °C in the presence and absence of antigen and obtained good agreement with the literature. Moreover, we used the FcεRI-IgE receptor-antibody system to directly compare the performance of UCNP-based SPT labels to organic dyes (AlexaFluor647) and quantum dots (QD655). Due to their photostability as well as their backgroundless and continuous luminescence, SPT trajectories obtained with UCNP labels are no longer limited by the photophysics of the label but only by the dynamics of the system and, in particular, the movement of the label out of the field of view and/or focal plane.
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Affiliation(s)
- Oleksii Dukhno
- Laboratory of Biomaging and Pathologies, UMR 7021 CNRS, University of Strasbourg, Strasbourg 67000, France
| | - Srijayee Ghosh
- Laboratory of Biomaging and Pathologies, UMR 7021 CNRS, University of Strasbourg, Strasbourg 67000, France
| | - Vanille Greiner
- Laboratory of Biomaging and Pathologies, UMR 7021 CNRS, University of Strasbourg, Strasbourg 67000, France
| | - Sophie Bou
- Laboratory of Biomaging and Pathologies, UMR 7021 CNRS, University of Strasbourg, Strasbourg 67000, France
| | - Julien Godet
- Laboratory of Biomaging and Pathologies, UMR 7021 CNRS, University of Strasbourg, Strasbourg 67000, France
- IMAGeS team at ICube, UMR 7357, CNRS, Université de Strasbourg, Strasbourg 67000, France
| | - Verena Muhr
- Institute of Analytical Chemistry, Chemo- and Biosensors, University of Regensburg, 93040 Regensburg, Germany
| | - Markus Buchner
- Institute of Analytical Chemistry, Chemo- and Biosensors, University of Regensburg, 93040 Regensburg, Germany
| | - Thomas Hirsch
- Institute of Analytical Chemistry, Chemo- and Biosensors, University of Regensburg, 93040 Regensburg, Germany
| | - Yves Mély
- Laboratory of Biomaging and Pathologies, UMR 7021 CNRS, University of Strasbourg, Strasbourg 67000, France
| | - Frédéric Przybilla
- Laboratory of Biomaging and Pathologies, UMR 7021 CNRS, University of Strasbourg, Strasbourg 67000, France
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15
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Tirumala NA, Redpath GMI, Skerhut SV, Dolai P, Kapoor-Kaushik N, Ariotti N, Vijay Kumar K, Ananthanarayanan V. Single-molecule imaging of stochastic interactions that drive dynein activation and cargo movement in cells. J Cell Biol 2024; 223:e202210026. [PMID: 38240798 PMCID: PMC10798859 DOI: 10.1083/jcb.202210026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Revised: 07/10/2023] [Accepted: 12/13/2023] [Indexed: 01/22/2024] Open
Abstract
Cytoplasmic dynein 1 (dynein) is the primary minus end-directed motor protein in most eukaryotic cells. Dynein remains in an inactive conformation until the formation of a tripartite complex comprising dynein, its regulator dynactin, and a cargo adaptor. How this process of dynein activation occurs is unclear since it entails the formation of a three-protein complex inside the crowded environs of a cell. Here, we employed live-cell, single-molecule imaging to visualize and track fluorescently tagged dynein. First, we observed that only ∼30% of dynein molecules that bound to the microtubule (MT) engaged in minus end-directed movement, and that too for a short duration of ∼0.6 s. Next, using high-resolution imaging in live and fixed cells and using correlative light and electron microscopy, we discovered that dynactin and endosomal cargo remained in proximity to each other and to MTs. We then employed two-color imaging to visualize cargo movement effected by single motor binding. Finally, we performed long-term imaging to show that short movements are sufficient to drive cargo to the perinuclear region of the cell. Taken together, we discovered a search mechanism that is facilitated by dynein's frequent MT binding-unbinding kinetics: (i) in a futile event when dynein does not encounter cargo anchored in proximity to the MT, dynein dissociates and diffuses into the cytoplasm, (ii) when dynein encounters cargo and dynactin upon MT binding, it moves cargo in a short run. Several of these short runs are undertaken in succession for long-range directed movement. In conclusion, we demonstrate that dynein activation and cargo capture are coupled in a step that relies on the reduction of dimensionality to enable minus end-directed transport in cellulo and that complex cargo behavior emerges from stochastic motor-cargo interactions.
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Affiliation(s)
| | - Gregory Michael Ian Redpath
- EMBL Australia Node in Single Molecule Science, Department of Molecular MedicineSchool of Biomedical Sciences, University of New South Wales, Sydney, Australia
| | - Sarah Viktoria Skerhut
- EMBL Australia Node in Single Molecule Science, Department of Molecular MedicineSchool of Biomedical Sciences, University of New South Wales, Sydney, Australia
| | - Pritha Dolai
- International Centre for Theoretical Sciences, Tata Institute of Fundamental Research, Bengaluru, India
| | | | - Nicholas Ariotti
- Electron Microscopy Unit, University of New South Wales, Sydney, Australia
| | - K. Vijay Kumar
- International Centre for Theoretical Sciences, Tata Institute of Fundamental Research, Bengaluru, India
| | - Vaishnavi Ananthanarayanan
- EMBL Australia Node in Single Molecule Science, Department of Molecular MedicineSchool of Biomedical Sciences, University of New South Wales, Sydney, Australia
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16
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Chung SC. Cryo-forum: A framework for orientation recovery with uncertainty measure with the application in cryo-EM image analysis. J Struct Biol 2024; 216:108058. [PMID: 38163450 DOI: 10.1016/j.jsb.2023.108058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Revised: 12/14/2023] [Accepted: 12/28/2023] [Indexed: 01/03/2024]
Abstract
In single-particle cryo-electron microscopy (cryo-EM), efficient determination of orientation parameters for particle images poses a significant challenge yet is crucial for reconstructing 3D structures. This task is complicated by the high noise levels in the datasets, which often include outliers, necessitating several time-consuming 2D clean-up processes. Recently, solutions based on deep learning have emerged, offering a more streamlined approach to the traditionally laborious task of orientation estimation. These solutions employ amortized inference, eliminating the need to estimate parameters individually for each image. However, these methods frequently overlook the presence of outliers and may not adequately concentrate on the components used within the network. This paper introduces a novel method using a 10-dimensional feature vector for orientation representation, extracting orientations as unit quaternions with an accompanying uncertainty metric. Furthermore, we propose a unique loss function that considers the pairwise distances between orientations, thereby enhancing the accuracy of our method. Finally, we also comprehensively evaluate the design choices in constructing the encoder network, a topic that has not received sufficient attention in the literature. Our numerical analysis demonstrates that our methodology effectively recovers orientations from 2D cryo-EM images in an end-to-end manner. Notably, the inclusion of uncertainty quantification allows for direct clean-up of the dataset at the 3D level. Lastly, we package our proposed methods into a user-friendly software suite named cryo-forum, designed for easy access by developers.
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Affiliation(s)
- Szu-Chi Chung
- Department of Applied Mathematics, National Sun Yat-sen University, No. 70, Lienhai Rd, Kaohsiung, Taiwan.
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17
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Sun W, Liu Z, Jiang X, Chen MB, Dong H, Liu J, Südhof TC, Quake SR. Spatial transcriptomics reveal neuron-astrocyte synergy in long-term memory. Nature 2024; 627:374-381. [PMID: 38326616 PMCID: PMC10937396 DOI: 10.1038/s41586-023-07011-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Accepted: 12/21/2023] [Indexed: 02/09/2024]
Abstract
Memory encodes past experiences, thereby enabling future plans. The basolateral amygdala is a centre of salience networks that underlie emotional experiences and thus has a key role in long-term fear memory formation1. Here we used spatial and single-cell transcriptomics to illuminate the cellular and molecular architecture of the role of the basolateral amygdala in long-term memory. We identified transcriptional signatures in subpopulations of neurons and astrocytes that were memory-specific and persisted for weeks. These transcriptional signatures implicate neuropeptide and BDNF signalling, MAPK and CREB activation, ubiquitination pathways, and synaptic connectivity as key components of long-term memory. Notably, upon long-term memory formation, a neuronal subpopulation defined by increased Penk and decreased Tac expression constituted the most prominent component of the memory engram of the basolateral amygdala. These transcriptional changes were observed both with single-cell RNA sequencing and with single-molecule spatial transcriptomics in intact slices, thereby providing a rich spatial map of a memory engram. The spatial data enabled us to determine that this neuronal subpopulation interacts with adjacent astrocytes, and functional experiments show that neurons require interactions with astrocytes to encode long-term memory.
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Affiliation(s)
- Wenfei Sun
- Department of Bioengineering, Stanford University, Stanford, CA, USA
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA, USA
| | - Zhihui Liu
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA, USA
- Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA, USA
| | - Xian Jiang
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA, USA
| | - Michelle B Chen
- Department of Bioengineering, Stanford University, Stanford, CA, USA
| | - Hua Dong
- Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, CA, USA
| | - Jonathan Liu
- Chan Zuckerberg Initiative, Redwood City, CA, USA
| | - Thomas C Südhof
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA, USA.
- Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA, USA.
| | - Stephen R Quake
- Department of Bioengineering, Stanford University, Stanford, CA, USA.
- Chan Zuckerberg Initiative, Redwood City, CA, USA.
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18
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Sakuragi T, Kanai R, Otani M, Kikkawa M, Toyoshima C, Nagata S. The role of the C-terminal tail region as a plug to regulate XKR8 lipid scramblase. J Biol Chem 2024; 300:105755. [PMID: 38364890 PMCID: PMC10938166 DOI: 10.1016/j.jbc.2024.105755] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 01/27/2024] [Accepted: 02/10/2024] [Indexed: 02/18/2024] Open
Abstract
XK-related 8 (XKR8), in complex with the transmembrane glycoprotein basigin, functions as a phospholipid scramblase activated by the caspase-mediated cleavage or phosphorylation of its C-terminal tail. It carries a putative phospholipid translocation path of multiple hydrophobic and charged residues in the transmembrane region. It also has a crucial tryptophan at the exoplasmic end of the path that regulates its scrambling activity. We herein investigated the tertiary structure of the human XKR8-basigin complex embedded in lipid nanodiscs at an overall resolution of 3.66 Å. We found that the C-terminal tail engaged in intricate polar and van der Waals interactions with a groove at the cytoplasmic surface of XKR8. These interactions maintained the inactive state of XKR8. Point mutations to disrupt these interactions strongly enhanced the scrambling activity of XKR8, suggesting that the activation of XKR8 is mediated by releasing the C-terminal tail from the cytoplasmic groove. We speculate that the cytoplasmic tail region of XKR8 functions as a plug to prevent the scrambling of phospholipids.
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Affiliation(s)
- Takaharu Sakuragi
- Laboratory of Biochemistry and Immunology, World Premier International Immunology Frontier Research Center, Osaka University, Suita, Osaka, Japan
| | - Ryuta Kanai
- Institute for Quantitative Biosciences, The University of Tokyo, Tokyo, Japan
| | - Mayumi Otani
- Laboratory of Biochemistry and Immunology, World Premier International Immunology Frontier Research Center, Osaka University, Suita, Osaka, Japan
| | - Masahide Kikkawa
- Department of Cell Biology and Anatomy, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Chikashi Toyoshima
- Institute for Quantitative Biosciences, The University of Tokyo, Tokyo, Japan
| | - Shigekazu Nagata
- Laboratory of Biochemistry and Immunology, World Premier International Immunology Frontier Research Center, Osaka University, Suita, Osaka, Japan.
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19
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Tang H, Xiao Y, Qian L, Wang Z, Lu M, Yao N, Zhou T, Tian F, Cao L, Zheng P, Dong X. Mechanistic insights into the C-type lectin receptor CLEC12A-mediated immune recognition of monosodium urate crystal. J Biol Chem 2024; 300:105765. [PMID: 38367667 PMCID: PMC10959670 DOI: 10.1016/j.jbc.2024.105765] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Revised: 02/06/2024] [Accepted: 02/13/2024] [Indexed: 02/19/2024] Open
Abstract
CLEC12A, a member of the C-type lectin receptor family involved in immune homeostasis, recognizes MSU crystals released from dying cells. However, the molecular mechanism underlying the CLEC12A-mediated recognition of MSU crystals remains unclear. Herein, we reported the crystal structure of the human CLEC12A-C-type lectin-like domain (CTLD) and identified a unique "basic patch" site on CLEC12A-CTLD that is necessary for the binding of MSU crystals. Meanwhile, we determined the interaction strength between CLEC12A-CTLD and MSU crystals using single-molecule force spectroscopy. Furthermore, we found that CLEC12A clusters at the cell membrane and seems to serve as an internalizing receptor of MSU crystals. Altogether, these findings provide mechanistic insights for understanding the molecular mechanisms underlying the interplay between CLEC12A and MSU crystals.
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Affiliation(s)
- Hua Tang
- State Key Laboratory of Pharmaceutical Biotechnology, Department of Biochemistry, School of Life Sciences, Nanjing University, Nanjing, China; Engineering Research Center of Protein and Peptide Medicine, Ministry of Education, Nanjing, China.
| | - Yuelong Xiao
- State Key Laboratory of Coordination Chemistry, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, Jiangsu, China
| | - Lei Qian
- State Key Laboratory of Pharmaceutical Biotechnology, Department of Biochemistry, School of Life Sciences, Nanjing University, Nanjing, China
| | - Zibin Wang
- State Key Laboratory of Pharmaceutical Biotechnology, Department of Biochemistry, School of Life Sciences, Nanjing University, Nanjing, China
| | - Ming Lu
- Westlake laboratory, Westlake University, Hangzhou, Zhejiang, China
| | - Nan Yao
- State Key Laboratory of Pharmaceutical Biotechnology, Department of Biochemistry, School of Life Sciences, Nanjing University, Nanjing, China
| | - Ting Zhou
- State Key Laboratory of Pharmaceutical Biotechnology, Department of Biochemistry, School of Life Sciences, Nanjing University, Nanjing, China
| | - Fang Tian
- State Key Laboratory of Coordination Chemistry, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, Jiangsu, China
| | - Longxing Cao
- Westlake laboratory, Westlake University, Hangzhou, Zhejiang, China
| | - Peng Zheng
- State Key Laboratory of Coordination Chemistry, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, Jiangsu, China.
| | - Xianchi Dong
- State Key Laboratory of Pharmaceutical Biotechnology, Department of Biochemistry, School of Life Sciences, Nanjing University, Nanjing, China; Engineering Research Center of Protein and Peptide Medicine, Ministry of Education, Nanjing, China; Institute of Artificial Intelligence Biomedicine, Nanjing University, Nanjing, China.
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20
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Tran BM, Punter CM, Linnik D, Iyer A, Poolman B. Single-protein Diffusion in the Periplasm of Escherichia coli. J Mol Biol 2024; 436:168420. [PMID: 38143021 DOI: 10.1016/j.jmb.2023.168420] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Revised: 12/13/2023] [Accepted: 12/19/2023] [Indexed: 12/26/2023]
Abstract
The width of the periplasmic space of Gram-negative bacteria is only about 25-30 nm along the long axis of the cell, which affects free diffusion of (macro)molecules. We have performed single-particle displacement measurements and diffusion simulation studies to determine the impact of confinement on the apparent mobility of proteins in the periplasm of Escherichia coli. The diffusion of a reporter protein and of OsmY, an osmotically regulated periplasmic protein, is characterized by a fast and slow component regardless of the osmotic conditions. The diffusion coefficient of the fast fraction increases upon osmotic upshift, in agreement with a decrease in macromolecular crowding of the periplasm, but the mobility of the slow (immobile) fraction is not affected by the osmotic stress. We observe that the confinement created by the inner and outer membranes results in a lower apparent diffusion coefficient, but this can only partially explain the slow component of diffusion in the particle displacement measurements, suggesting that a fraction of the proteins is hindered in its mobility by large periplasmic structures. Using particle-based simulations, we have determined the confinement effect on the apparent diffusion coefficient of the particles for geometries akin the periplasmic space of Gram-negative bacteria.
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Affiliation(s)
- Buu Minh Tran
- Department of Biochemistry, University of Groningen, Nijenborgh 4, 9747 AG Groningen, the Netherlands
| | - Christiaan Michiel Punter
- Department of Biochemistry, University of Groningen, Nijenborgh 4, 9747 AG Groningen, the Netherlands
| | - Dmitrii Linnik
- Department of Biochemistry, University of Groningen, Nijenborgh 4, 9747 AG Groningen, the Netherlands
| | - Aditya Iyer
- Department of Biochemistry, University of Groningen, Nijenborgh 4, 9747 AG Groningen, the Netherlands
| | - Bert Poolman
- Department of Biochemistry, University of Groningen, Nijenborgh 4, 9747 AG Groningen, the Netherlands.
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21
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Bozděchová L, Havlová K, Fajkus P, Fajkus J. Analysis of Telomerase RNA Structure in Physcomitrium patens Indicates Functionally Relevant Transitions Between OPEN and CLOSED Conformations. J Mol Biol 2024; 436:168417. [PMID: 38143018 DOI: 10.1016/j.jmb.2023.168417] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Revised: 12/19/2023] [Accepted: 12/19/2023] [Indexed: 12/26/2023]
Abstract
Telomerase RNA (TR) conformation determines its function as a template for telomere synthesis and as a scaffold for the assembly of the telomerase nucleoprotein complex. Experimental analyses of TR secondary structure using DMS-Map Seq and SHAPE-Map Seq techniques show its CLOSED conformation as the consensus structure where the template region cannot perform its function. Our data show that the apparent discrepancy between experimental results and predicted TR functional conformation, mostly ignored in published studies, can be explained using data analysis based on single-molecule structure prediction from individual sequencing reads by the recently established DaVinci method. This method results in several clusters of secondary structures reflecting the structural dynamics of TR, possibly related to its multiple functional states. Interestingly, the presumed active (OPEN) conformation of TR corresponds to a minor fraction of TR under in vivo conditions. Therefore, structural polymorphism and dynamic TR transitions between CLOSED and OPEN conformations may be involved in telomerase activity regulation as a switch that functions independently of total TR transcript levels.
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Affiliation(s)
- Lucie Bozděchová
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology, Masaryk University, Kamenice 5, 62500 Brno, Czech Republic
| | - Kateřina Havlová
- National Center for Biomolecular Research, Faculty of Science, Masaryk University, Kamenice 5, 62500 Brno, Czech Republic
| | - Petr Fajkus
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology, Masaryk University, Kamenice 5, 62500 Brno, Czech Republic; Institute of Biophysics, Czech Acad Sci, Královopolská 135, 61200 Brno, Czech Republic
| | - Jiří Fajkus
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology, Masaryk University, Kamenice 5, 62500 Brno, Czech Republic; National Center for Biomolecular Research, Faculty of Science, Masaryk University, Kamenice 5, 62500 Brno, Czech Republic; Institute of Biophysics, Czech Acad Sci, Královopolská 135, 61200 Brno, Czech Republic.
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22
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Padmanabhan P, Kneynsberg A, Cruz E, Briner A, Götz J. Single-molecule imaging of Tau reveals how phosphorylation affects its movement and confinement in living cells. Mol Brain 2024; 17:7. [PMID: 38347594 PMCID: PMC10863257 DOI: 10.1186/s13041-024-01078-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2023] [Accepted: 01/22/2024] [Indexed: 02/15/2024] Open
Abstract
Tau is a microtubule-associated protein that is regulated by post-translational modifications. The most studied of these modifications is phosphorylation, which affects Tau's aggregation and loss- and gain-of-functions, including the interaction with microtubules, in Alzheimer's disease and primary tauopathies. However, little is known about how Tau's phosphorylation state affects its dynamics and organisation at the single-molecule level. Here, using quantitative single-molecule localisation microscopy, we examined how mimicking or abrogating phosphorylation at 14 disease-associated serine and threonine residues through mutagenesis influences the behaviour of Tau in live Neuro-2a cells. We observed that both pseudohyperphosphorylated Tau (TauE14) and phosphorylation-deficient Tau (TauA14) exhibit a heterogeneous mobility pattern near the plasma membrane. Notably, we found that the mobility of TauE14 molecules was higher than wild-type Tau molecules, while TauA14 molecules displayed lower mobility. Moreover, TauA14 was organised in a filament-like structure resembling cytoskeletal filaments, within which TauA14 exhibited spatial and kinetic heterogeneity. Our study provides a direct visualisation of how the phosphorylation state of Tau affects its spatial and temporal organisation, presumably reflecting the phosphorylation-dependent changes in the interactions between Tau and its partners. We suggest that alterations in Tau dynamics resulting from aberrant changes in phosphorylation could be a critical step in its pathological dysregulation.
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Affiliation(s)
- Pranesh Padmanabhan
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, 4072, Brisbane, Australia.
| | - Andrew Kneynsberg
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, 4072, Brisbane, Australia
| | - Esteban Cruz
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, 4072, Brisbane, Australia
| | - Adam Briner
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, 4072, Brisbane, Australia
| | - Jürgen Götz
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, 4072, Brisbane, Australia.
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23
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Qiu Y, Sajidah ES, Kondo S, Narimatsu S, Sandira MI, Higashiguchi Y, Nishide G, Taoka A, Hazawa M, Inaba Y, Inoue H, Matsushima A, Okada Y, Nakada M, Ando T, Lim K, Wong RW. An Efficient Method for Isolating and Purifying Nuclei from Mice Brain for Single-Molecule Imaging Using High-Speed Atomic Force Microscopy. Cells 2024; 13:279. [PMID: 38334671 PMCID: PMC10855070 DOI: 10.3390/cells13030279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Revised: 01/31/2024] [Accepted: 02/01/2024] [Indexed: 02/10/2024] Open
Abstract
Nuclear pore complexes (NPCs) on the nuclear membrane surface have a crucial function in controlling the movement of small molecules and macromolecules between the cell nucleus and cytoplasm through their intricate core channel resembling a spiderweb with several layers. Currently, there are few methods available to accurately measure the dynamics of nuclear pores on the nuclear membranes at the nanoscale. The limitation of traditional optical imaging is due to diffraction, which prevents achieving the required resolution for observing a diverse array of organelles and proteins within cells. Super-resolution techniques have effectively addressed this constraint by enabling the observation of subcellular components on the nanoscale. Nevertheless, it is crucial to acknowledge that these methods often need the use of fixed samples. This also raises the question of how closely a static image represents the real intracellular dynamic system. High-speed atomic force microscopy (HS-AFM) is a unique technique used in the field of dynamic structural biology, enabling the study of individual molecules in motion close to their native states. Establishing a reliable and repeatable technique for imaging mammalian tissue at the nanoscale using HS-AFM remains challenging due to inadequate sample preparation. This study presents the rapid strainer microfiltration (RSM) protocol for directly preparing high-quality nuclei from the mouse brain. Subsequently, we promptly utilize HS-AFM real-time imaging and cinematography approaches to record the spatiotemporal of nuclear pore nano-dynamics from the mouse brain.
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Affiliation(s)
- Yujia Qiu
- Division of Nano Life Science, Graduate School of Frontier Science Initiative, Kanazawa University, Kanazawa 920-1192, Japan; (Y.Q.); (M.I.S.)
| | - Elma Sakinatus Sajidah
- WPI Nano Life Science Institute (WPI-NanoLSI), Kanazawa University, Kanazawa 920-1192, Japan (M.H.); (T.A.)
| | - Sota Kondo
- Division of Nano Life Science, Graduate School of Frontier Science Initiative, Kanazawa University, Kanazawa 920-1192, Japan; (Y.Q.); (M.I.S.)
| | - Shinnosuke Narimatsu
- Division of Nano Life Science, Graduate School of Frontier Science Initiative, Kanazawa University, Kanazawa 920-1192, Japan; (Y.Q.); (M.I.S.)
| | - Muhammad Isman Sandira
- Division of Nano Life Science, Graduate School of Frontier Science Initiative, Kanazawa University, Kanazawa 920-1192, Japan; (Y.Q.); (M.I.S.)
| | - Yoshiki Higashiguchi
- Division of Nano Life Science, Graduate School of Frontier Science Initiative, Kanazawa University, Kanazawa 920-1192, Japan; (Y.Q.); (M.I.S.)
| | - Goro Nishide
- Division of Nano Life Science, Graduate School of Frontier Science Initiative, Kanazawa University, Kanazawa 920-1192, Japan; (Y.Q.); (M.I.S.)
| | - Azuma Taoka
- WPI Nano Life Science Institute (WPI-NanoLSI), Kanazawa University, Kanazawa 920-1192, Japan (M.H.); (T.A.)
| | - Masaharu Hazawa
- WPI Nano Life Science Institute (WPI-NanoLSI), Kanazawa University, Kanazawa 920-1192, Japan (M.H.); (T.A.)
- Cell-Bionomics Research Unit, Innovative Integrated Bio-Research Core, Institute for Frontier Science Initiative, Kanazawa University, Kanazawa 920-1192, Japan
| | - Yuka Inaba
- Metabolism and Nutrition Research Unit, Institute for Frontier Science Initiative, Kanazawa University, Kanazawa 920-8641, Japan
| | - Hiroshi Inoue
- Metabolism and Nutrition Research Unit, Institute for Frontier Science Initiative, Kanazawa University, Kanazawa 920-8641, Japan
| | - Ayami Matsushima
- Laboratory of Structure-Function Biochemistry, Department of Chemistry, Faculty of Science, Kyushu University, Fukuoka 819-0395, Japan
| | - Yuki Okada
- Institute for Quantitative Biosciences, The University of Tokyo, Tokyo 113-0033, Japan
| | - Mitsutoshi Nakada
- Department of Neurosurgery, Graduate School of Medical Science, Kanazawa University, Kanazawa 920-8641, Japan
| | - Toshio Ando
- WPI Nano Life Science Institute (WPI-NanoLSI), Kanazawa University, Kanazawa 920-1192, Japan (M.H.); (T.A.)
| | - Keesiang Lim
- WPI Nano Life Science Institute (WPI-NanoLSI), Kanazawa University, Kanazawa 920-1192, Japan (M.H.); (T.A.)
| | - Richard W. Wong
- Division of Nano Life Science, Graduate School of Frontier Science Initiative, Kanazawa University, Kanazawa 920-1192, Japan; (Y.Q.); (M.I.S.)
- WPI Nano Life Science Institute (WPI-NanoLSI), Kanazawa University, Kanazawa 920-1192, Japan (M.H.); (T.A.)
- Cell-Bionomics Research Unit, Innovative Integrated Bio-Research Core, Institute for Frontier Science Initiative, Kanazawa University, Kanazawa 920-1192, Japan
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24
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Priessner M, Gaboriau DCA, Sheridan A, Lenn T, Garzon-Coral C, Dunn AR, Chubb JR, Tousley AM, Majzner RG, Manor U, Vilar R, Laine RF. Content-aware frame interpolation (CAFI): deep learning-based temporal super-resolution for fast bioimaging. Nat Methods 2024; 21:322-330. [PMID: 38238557 PMCID: PMC10864186 DOI: 10.1038/s41592-023-02138-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Accepted: 11/17/2023] [Indexed: 02/15/2024]
Abstract
The development of high-resolution microscopes has made it possible to investigate cellular processes in 3D and over time. However, observing fast cellular dynamics remains challenging because of photobleaching and phototoxicity. Here we report the implementation of two content-aware frame interpolation (CAFI) deep learning networks, Zooming SlowMo and Depth-Aware Video Frame Interpolation, that are highly suited for accurately predicting images in between image pairs, therefore improving the temporal resolution of image series post-acquisition. We show that CAFI is capable of understanding the motion context of biological structures and can perform better than standard interpolation methods. We benchmark CAFI's performance on 12 different datasets, obtained from four different microscopy modalities, and demonstrate its capabilities for single-particle tracking and nuclear segmentation. CAFI potentially allows for reduced light exposure and phototoxicity on the sample for improved long-term live-cell imaging. The models and the training and testing data are available via the ZeroCostDL4Mic platform.
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Affiliation(s)
- Martin Priessner
- Department of Chemistry, Imperial College London, London, UK.
- Centre of Excellence in Neurotechnology, Imperial College London, London, UK.
| | - David C A Gaboriau
- Facility for Imaging by Light Microscopy, NHLI, Imperial College London, London, UK
| | - Arlo Sheridan
- Waitt Advanced Biophotonics Center, Salk Institute for Biological Studies, La Jolla, CA, USA
| | - Tchern Lenn
- CRUK City of London Centre, UCL Cancer Institute, London, UK
| | - Carlos Garzon-Coral
- Department of Pediatrics, Stanford University School of Medicine, Stanford, CA, USA
- Institute of Human Biology, Roche Pharma Research & Early Development, Roche Innovation Center Basel, Basel, Switzerland
| | - Alexander R Dunn
- Department of Pediatrics, Stanford University School of Medicine, Stanford, CA, USA
| | - Jonathan R Chubb
- Laboratory for Molecular Cell Biology, University College London, London, UK
| | - Aidan M Tousley
- Department of Chemical Engineering, Stanford University, Stanford, CA, USA
| | - Robbie G Majzner
- Department of Chemical Engineering, Stanford University, Stanford, CA, USA
| | - Uri Manor
- Waitt Advanced Biophotonics Center, Salk Institute for Biological Studies, La Jolla, CA, USA
- Department of Cell & Developmental Biology, University of California, San Diego, CA, USA
| | - Ramon Vilar
- Department of Chemistry, Imperial College London, London, UK
| | - Romain F Laine
- Micrographia Bio, Translation and Innovation Hub, London, UK.
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25
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Palao L, Murakami K, Chang YW. Combining per-particle cryo-ET and cryo-EM single particle analysis to elucidate heterogeneous DNA-protein organization. Curr Opin Struct Biol 2024; 84:102765. [PMID: 38181688 PMCID: PMC10922635 DOI: 10.1016/j.sbi.2023.102765] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2023] [Revised: 12/06/2023] [Accepted: 12/11/2023] [Indexed: 01/07/2024]
Abstract
Cryo-electron microscopy single particle analysis (cryo-EM SPA) and cryo-electron tomography (cryo-ET) have historically been employed as distinct approaches for investigating molecular structures of disparate sample types, focusing on highly purified biological macromolecules and in situ cellular contexts, respectively. However, these techniques offer inherently complementary structural insights that, when combined, provide a more comprehensive understanding of complex biological systems. For example, if both techniques are applied to the same purified biological macromolecules, cryo-ET has the ability to resolve highly flexible yet strong signal features on an individual target molecule which will not be preserved in the high-resolution cryo-EM SPA results. In this review, we highlight recent achievements utilizing such applications to unveil new insights into the chromatin assembly and activities of DNA-protein assemblies. This convergence of cryo-EM SPA and cryo-ET holds great promise for elucidating new structural aspects of these essential molecular processes.
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Affiliation(s)
- Leon Palao
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, PA, USA; Biochemistry and Molecular Biophysics Graduate Group, Perelman School of Medicine, University of Pennsylvania, PA, USA
| | - Kenji Murakami
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, PA, USA; Biochemistry and Molecular Biophysics Graduate Group, Perelman School of Medicine, University of Pennsylvania, PA, USA; Institute of Structural Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
| | - Yi-Wei Chang
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, PA, USA; Biochemistry and Molecular Biophysics Graduate Group, Perelman School of Medicine, University of Pennsylvania, PA, USA; Institute of Structural Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
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26
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Li Z, Zhang L, Wang Z, Kang X, Jin H, Zhao W, Zhang J, Su H. Quantification of Phosphatidylserine Molecules on the Surface of Individual Cells Using Single-Molecule Force Spectroscopy. Anal Chem 2024; 96:676-684. [PMID: 38173079 DOI: 10.1021/acs.analchem.3c03517] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
Identification of the phosphatidylserine (PS) discrepancies occurring on the cellular membrane during apoptotic processes is of the utmost importance. However, monitoring the quantity of PS molecules in real-time at a single-cell level currently remains a challenging task. Here, we demonstrate this objective by leveraging the specific binding and reversible interaction exhibited by the zinc(II) dipyridinamine complex (ZnDPA) with PS. Lipoic acid-functionalized ZnDPA (LP-ZnDPA) was subsequently immobilized onto the surface of an atomic force microscopy cantilever to form a force probe, ALP-ZnDPA, enabling a PS-specific dynamic imaging and detection mode. By utilizing this technique, we can not only create a heat map of the expression level of PS with submicron resolution but also quantify the number of molecules present on a single cell's surface with a detection limit of 1.86 × 104 molecules. The feasibility of the proposed method is demonstrated through the analysis of PS expression levels in different cancer cell lines and at various stages of paclitaxel-induced apoptosis. This study represents the first application of a force probe to quantify PS molecules on the surface of individual cells, providing insight into dynamic changes in PS content during apoptosis at the molecular level and introducing a novel dimension to current detection methodologies.
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Affiliation(s)
- Zhirong Li
- Inner Mongolia Key Laboratory of Chemistry and Physics of Rare Earth Materials, School of Chemistry and Chemical Engineering, Inner Mongolia University, Hohhot 010020, China
| | - Lulu Zhang
- Inner Mongolia Key Laboratory of Chemistry and Physics of Rare Earth Materials, School of Chemistry and Chemical Engineering, Inner Mongolia University, Hohhot 010020, China
| | - Zhanzhong Wang
- Inner Mongolia Key Laboratory of Chemistry and Physics of Rare Earth Materials, School of Chemistry and Chemical Engineering, Inner Mongolia University, Hohhot 010020, China
| | - Xiongli Kang
- Inner Mongolia Key Laboratory of Chemistry and Physics of Rare Earth Materials, School of Chemistry and Chemical Engineering, Inner Mongolia University, Hohhot 010020, China
| | - Huiying Jin
- Inner Mongolia Key Laboratory of Chemistry and Physics of Rare Earth Materials, School of Chemistry and Chemical Engineering, Inner Mongolia University, Hohhot 010020, China
| | - Wenjie Zhao
- Inner Mongolia Key Laboratory of Chemistry and Physics of Rare Earth Materials, School of Chemistry and Chemical Engineering, Inner Mongolia University, Hohhot 010020, China
| | - Jun Zhang
- Inner Mongolia Key Laboratory of Chemistry and Physics of Rare Earth Materials, School of Chemistry and Chemical Engineering, Inner Mongolia University, Hohhot 010020, China
| | - Haiquan Su
- Inner Mongolia Key Laboratory of Chemistry and Physics of Rare Earth Materials, School of Chemistry and Chemical Engineering, Inner Mongolia University, Hohhot 010020, China
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27
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Kemmoku H, Takahashi K, Mukai K, Mori T, Hirosawa KM, Kiku F, Uchida Y, Kuchitsu Y, Nishioka Y, Sawa M, Kishimoto T, Tanaka K, Yokota Y, Arai H, Suzuki KGN, Taguchi T. Single-molecule localization microscopy reveals STING clustering at the trans-Golgi network through palmitoylation-dependent accumulation of cholesterol. Nat Commun 2024; 15:220. [PMID: 38212328 PMCID: PMC10784591 DOI: 10.1038/s41467-023-44317-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Accepted: 12/07/2023] [Indexed: 01/13/2024] Open
Abstract
Stimulator of interferon genes (STING) is critical for the type I interferon response to pathogen- or self-derived DNA in the cytosol. STING may function as a scaffold to activate TANK-binding kinase 1 (TBK1), but direct cellular evidence remains lacking. Here we show, using single-molecule imaging of STING with enhanced time resolutions down to 5 ms, that STING becomes clustered at the trans-Golgi network (about 20 STING molecules per cluster). The clustering requires STING palmitoylation and the Golgi lipid order defined by cholesterol. Single-molecule imaging of TBK1 reveals that STING clustering enhances the association with TBK1. We thus provide quantitative proof-of-principle for the signaling STING scaffold, reveal the mechanistic role of STING palmitoylation in the STING activation, and resolve the long-standing question of the requirement of STING translocation for triggering the innate immune signaling.
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Affiliation(s)
- Haruka Kemmoku
- Laboratory of Organelle Pathophysiology, Department of Integrative Life Sciences, Graduate School of Life Sciences, Tohoku University, Sendai, Japan
| | - Kanoko Takahashi
- Laboratory of Organelle Pathophysiology, Department of Integrative Life Sciences, Graduate School of Life Sciences, Tohoku University, Sendai, Japan
| | - Kojiro Mukai
- Laboratory of Organelle Pathophysiology, Department of Integrative Life Sciences, Graduate School of Life Sciences, Tohoku University, Sendai, Japan
| | - Toshiki Mori
- United Graduate School of Agricultural Science, Gifu University, Gifu, Japan
| | | | - Fumika Kiku
- Department of Health Chemistry, Graduate School of Pharmaceutical Sciences, University of Tokyo, Tokyo, Japan
| | - Yasunori Uchida
- Laboratory of Organelle Pathophysiology, Department of Integrative Life Sciences, Graduate School of Life Sciences, Tohoku University, Sendai, Japan
| | - Yoshihiko Kuchitsu
- Laboratory of Organelle Pathophysiology, Department of Integrative Life Sciences, Graduate School of Life Sciences, Tohoku University, Sendai, Japan
| | - Yu Nishioka
- Research and Development, Carna Biosciences, Inc., Kobe, Japan
| | - Masaaki Sawa
- Research and Development, Carna Biosciences, Inc., Kobe, Japan
| | - Takuma Kishimoto
- Division of Molecular Interaction, Institute for Genetic Medicine, Hokkaido University Graduate School of Life Science, Sapporo, Hokkaido, Japan
| | - Kazuma Tanaka
- Division of Molecular Interaction, Institute for Genetic Medicine, Hokkaido University Graduate School of Life Science, Sapporo, Hokkaido, Japan
| | - Yasunari Yokota
- Department of EECE, Faculty of Engineering, Gifu University, Gifu, Japan
| | - Hiroyuki Arai
- Department of Health Chemistry, Graduate School of Pharmaceutical Sciences, University of Tokyo, Tokyo, Japan
| | - Kenichi G N Suzuki
- Institute for Glyco-core Research (iGCORE), Gifu University, Gifu, Japan.
- Division of Advanced Bioimaging, National Cancer Center Research Institute, Tokyo, Japan.
| | - Tomohiko Taguchi
- Laboratory of Organelle Pathophysiology, Department of Integrative Life Sciences, Graduate School of Life Sciences, Tohoku University, Sendai, Japan.
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28
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Kim S, Shin WH, Kang Y, Kim H, Lee JY. Direct visualization of replication and R-loop collision using single-molecule imaging. Nucleic Acids Res 2024; 52:259-273. [PMID: 37994723 PMCID: PMC10783495 DOI: 10.1093/nar/gkad1101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Revised: 10/12/2023] [Accepted: 11/06/2023] [Indexed: 11/24/2023] Open
Abstract
R-loops are three-stranded nucleic acid structures that can cause replication stress by blocking replication fork progression. However, the detailed mechanism underlying the collision of DNA replication forks and R-loops remains elusive. To investigate how R-loops induce replication stress, we use single-molecule fluorescence imaging to directly visualize the collision of replicating Phi29 DNA polymerase (Phi29 DNAp), the simplest replication system, and R-loops. We demonstrate that a single R-loop can block replication, and the blockage is more pronounced when an RNA-DNA hybrid is on the non-template strand. We show that this asymmetry results from secondary structure formation on the non-template strand, which impedes the progression of Phi29 DNAp. We also show that G-quadruplex formation on the displaced single-stranded DNA in an R-loop enhances the replication stalling. Moreover, we observe the collision between Phi29 DNAp and RNA transcripts synthesized by T7 RNA polymerase (T7 RNAp). RNA transcripts cause more stalling because of the presence of T7 RNAp. Our work provides insights into how R-loops impede DNA replication at single-molecule resolution.
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Affiliation(s)
- Subin Kim
- Department of Biological Sciences, Ulsan National Institute of Science and Technology, Ulsan 44919, Republic of Korea
| | - Woo Hee Shin
- Department of Biological Sciences, Ulsan National Institute of Science and Technology, Ulsan 44919, Republic of Korea
| | - Yujin Kang
- Department of Biological Sciences, Ulsan National Institute of Science and Technology, Ulsan 44919, Republic of Korea
| | - Hongtae Kim
- Department of Biological Sciences, Ulsan National Institute of Science and Technology, Ulsan 44919, Republic of Korea
| | - Ja Yil Lee
- Department of Biological Sciences, Ulsan National Institute of Science and Technology, Ulsan 44919, Republic of Korea
- Institute of Basic Science Center for Genomic Integrity, Ulsan 44919, Republic of Korea
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29
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Yoshida SR, Chong S. Single-Molecule Measurement of Protein Interaction Dynamics within Biomolecular Condensates. J Vis Exp 2024. [PMID: 38251748 DOI: 10.3791/66169] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2024] Open
Abstract
Biomolecular condensates formed via liquid-liquid phase separation (LLPS) have been considered critical in cellular organization and an increasing number of cellular functions. Characterizing LLPS in live cells is also important because aberrant condensation has been linked to numerous diseases, including cancers and neurodegenerative disorders. LLPS is often driven by selective, transient, and multivalent interactions between intrinsically disordered proteins. Of great interest are the interaction dynamics of proteins participating in LLPS, which are well-summarized by measurements of their binding residence time (RT), that is, the amount of time they spend bound within condensates. Here, we present a method based on live-cell single-molecule imaging that allows us to measure the mean RT of a specific protein within condensates. We simultaneously visualize individual protein molecules and the condensates with which they associate, use single-particle tracking (SPT) to plot single-molecule trajectories, and then fit the trajectories to a model of protein-droplet binding to extract the mean RT of the protein. Finally, we show representative results where this single-molecule imaging method was applied to compare the mean RTs of a protein at its LLPS condensates when fused and unfused to an oligomerizing domain. This protocol is broadly applicable to measuring the interaction dynamics of any protein that participates in LLPS.
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Affiliation(s)
- Shawn R Yoshida
- Division of Chemistry and Chemical Engineering, California Institute of Technology; Division of Biology and Biological Engineering, California Institute of Technology
| | - Shasha Chong
- Division of Chemistry and Chemical Engineering, California Institute of Technology;
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30
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Pain C, Tynan C, Botchway SW, Kriechbaumer V. Variable-Angle Epifluorescence Microscopy for Single-Particle Tracking in the Plant ER. Methods Mol Biol 2024; 2772:273-283. [PMID: 38411821 DOI: 10.1007/978-1-0716-3710-4_20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/28/2024]
Abstract
Single-particle tracking (SPT) of biomolecules in the plant endoplasmic reticulum has the potential to inform on the formation of protein-protein complexes, metabolons, and the transport of molecules through both the ER membrane and lumen. Plant cells are particularly challenging for observing and tracking single molecules due to their unique structure, size, and considerable autofluorescence. However, by using variable-angle or highly inclined epifluorescence microscopy (VAEM) and transient expression in tobacco, it is possible to observe single-particle dynamics in the ER. Selecting the appropriate fluorophore, and ensuring the correct fluorophore density in the ER, is essential for successful SPT. By using tuneable fluorophores, which can be photoconverted and photoactivated, it is possible to vary the density of visible fluorophores in the ER dynamically. Here we describe methods to prepare plant samples for VAEM and two methods for determining and analyzing single-particle tracks from VAEM time series.
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Affiliation(s)
- Charlotte Pain
- Endomembrane Structure and Function Research Group, Department of Biological and Medical Sciences, Oxford Brookes University, Oxford, UK
| | - Christopher Tynan
- Central Laser Facility, Science and Technology Facilities Council (STFC) Rutherford Appleton Laboratory, Research Complex at Harwell, Didcot, UK
| | - Stanley W Botchway
- Central Laser Facility, Science and Technology Facilities Council (STFC) Rutherford Appleton Laboratory, Research Complex at Harwell, Didcot, UK
| | - Verena Kriechbaumer
- Endomembrane Structure and Function Research Group, Department of Biological and Medical Sciences, Oxford Brookes University, Oxford, UK.
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31
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Avellaneda MJ, Koers EJ, Sunderlikova V, Tans SJ. Protein Tethering for Single-Molecule Force Spectroscopy. Methods Mol Biol 2024; 2694:57-67. [PMID: 37823999 DOI: 10.1007/978-1-0716-3377-9_3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/13/2023]
Abstract
Molecular manipulation by optical tweezers is a central technique to study the folded states of individual proteins and how they depend on interactions with molecules including DNA, ligands, and other proteins. One of the key challenges of this approach is to stably attach DNA handles in an efficient manner. Here, we provide detailed descriptions of a universal approach to covalently link long DNA tethers of up to 5000 base pairs to proteins with or without native cysteines.
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32
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Zhang C, Manley S. Super-Resolution Microscopy of the Bacterial Cell Wall Labeled by Fluorescent D-Amino Acids. Methods Mol Biol 2024; 2727:83-94. [PMID: 37815710 DOI: 10.1007/978-1-0716-3491-2_7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/11/2023]
Abstract
Fluorescent D-amino acids (FDAAs) enable in situ visualization of bacterial cell wall synthesis via their incorporation into peptidoglycan (PG) crosslinks. When combined with super-resolution microscopy, FDAAs allow the details of cell wall synthesis to be resolved beyond the diffraction limit of visible light. Here, we describe using the super-resolution method of single-molecule localization microscopy (SMLM) in conjunction with two newly synthesized FDAAs (sCy5DA and sCy5DL_amide) to resolve bacterial PG at the nanoscale in a variety of species, including Gram-negative, Gram-positive, and mycobacteria.
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Affiliation(s)
- Chen Zhang
- Institute of Physics, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Suliana Manley
- Institute of Physics, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland.
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33
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Yeo WH, Sun C, Zhang HF. Physically informed Monte Carlo simulation of dual-wedge prism-based spectroscopic single-molecule localization microscopy. J Biomed Opt 2024; 29:S11502. [PMID: 37795311 PMCID: PMC10546470 DOI: 10.1117/1.jbo.29.s1.s11502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/20/2023] [Revised: 09/12/2023] [Accepted: 09/15/2023] [Indexed: 10/06/2023]
Abstract
Significance The dual-wedge prism (DWP)-based spectroscopic single-molecule localization microscopy (sSMLM) system offers improved localization precision and adjustable spectral or localization performance, but its nonlinear spectral dispersion presents a challenge. A systematic method can help understand the challenges and thereafter optimize the DWP system's performance by customizing the system parameters to maximize the spectral or localization performance for various molecular labels. Aim We developed a Monte Carlo (MC)-based model that predicts the imaging output of the DWP-based sSMLM system given different system parameters. Approach We assessed our MC model's localization and spectral precisions by comparing our simulation against theoretical equations and fluorescent microspheres. Furthermore, we simulated the DWP-based system using beamsplitters (BSs) with a reflectance (R):transmittance (T) of R50:T50 and R30:T70 and their tradeoffs. Results Our MC simulation showed average deviations of 2.5 and 2.1 nm for localization and spectral precisions against theoretical equations and 2.3 and 1.0 nm against fluorescent microspheres. An R30:T70 BS improved the spectral precision by 8% but worsened the localization precision by 35% on average compared with an R50:T50 BS. Conclusions The MC model accurately predicted the localization precision, spectral precision, spectral peaks, and spectral widths of fluorescent microspheres, as validated by experimental data. Our work enhances the theoretical understanding of DWP-based sSMLM for multiplexed imaging, enabling performance optimization.
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Affiliation(s)
- Wei-Hong Yeo
- Northwestern University, Department of Biomedical Engineering, Evanston, Illinois, United States
| | - Cheng Sun
- Northwestern University, Department of Mechanical Engineering, Evanston, Illinois, United States
| | - Hao F. Zhang
- Northwestern University, Department of Biomedical Engineering, Evanston, Illinois, United States
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34
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Hou CFD, Li F, Iglesias S, Cingolani G. Use of Localized Reconstruction to Visualize the Shigella Phage Sf6 Tail Apparatus. Methods Mol Biol 2024; 2738:215-228. [PMID: 37966602 PMCID: PMC10655839 DOI: 10.1007/978-1-0716-3549-0_14] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2023]
Abstract
Cryogenic electron microscopy (cryo-EM) single-particle analysis has revolutionized the structural analysis of icosahedral viruses, including tailed bacteriophages. In recent years, localized (or focused) reconstruction has emerged as a powerful data analysis method to capture symmetry mismatches and resolve asymmetric features in icosahedral viruses. Here, we describe the methods used to reconstruct the 2.65-MDa tail apparatus of the Shigella phage Sf6, a representative member of the Podoviridae superfamily.
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Affiliation(s)
- Chun-Feng David Hou
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, PA, USA
| | - Fenglin Li
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, PA, USA
| | - Stephano Iglesias
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, PA, USA
| | - Gino Cingolani
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, PA, USA.
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35
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Loseva E, van Krugten J, Mitra A, Peterman EJG. Single-Molecule Fluorescence Microscopy in Sensory Cilia of Living Caenorhabditis elegans. Methods Mol Biol 2024; 2694:133-150. [PMID: 37824003 DOI: 10.1007/978-1-0716-3377-9_7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/13/2023]
Abstract
Intracellular transport of organelles and biomolecules is vital for several cellular processes. Single-molecule fluorescence microscopy can illuminate molecular aspects of the dynamics of individual biomolecules that remain unresolved in ensemble experiments. For example, studying single-molecule trajectories of moving biomolecules can reveal motility properties such as velocity, diffusivity, location and duration of pauses, etc. We use single-molecule imaging to study the dynamics of microtubule-based motor proteins and their cargo in the primary cilia of living C. elegans. To this end, we employ standard fluorescent proteins, an epi-illuminated, widefield fluorescence microscope, and primarily open-source software. This chapter describes the setup we use, the preparation of samples, a protocol for single-molecule imaging in primary cilia of C. elegans, and data analysis.
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Affiliation(s)
- Elizaveta Loseva
- LaserLaB Amsterdam and Department of Physics and Astronomy, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Jaap van Krugten
- LaserLaB Amsterdam and Department of Physics and Astronomy, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Aniruddha Mitra
- LaserLaB Amsterdam and Department of Physics and Astronomy, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Erwin J G Peterman
- LaserLaB Amsterdam and Department of Physics and Astronomy, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands.
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36
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Qin G, Xu J, Liang Y, Fang X. Single-Molecule Imaging Reveals Differential AT1R Stoichiometry Change in Biased Signaling. Int J Mol Sci 2023; 25:374. [PMID: 38203545 PMCID: PMC10778740 DOI: 10.3390/ijms25010374] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Revised: 11/10/2023] [Accepted: 11/24/2023] [Indexed: 01/12/2024] Open
Abstract
G protein-coupled receptors (GPCRs) represent promising therapeutic targets due to their involvement in numerous physiological processes mediated by downstream G protein- and β-arrestin-mediated signal transduction cascades. Although the precise control of GPCR signaling pathways is therapeutically valuable, the molecular details for governing biased GPCR signaling remain elusive. The Angiotensin II type 1 receptor (AT1R), a prototypical class A GPCR with profound implications for cardiovascular functions, has become a focal point for biased ligand-based clinical interventions. Herein, we used single-molecule live-cell imaging techniques to evaluate the changes in stoichiometry and dynamics of AT1R with distinct biased ligand stimulations in real time. It was revealed that AT1R existed predominantly in monomers and dimers and underwent oligomerization upon ligand stimulation. Notably, β-arrestin-biased ligands induced the formation of higher-order aggregates, resulting in a slower diffusion profile for AT1R compared to G protein-biased ligands. Furthermore, we demonstrated that the augmented aggregation of AT1R, triggered by activation from each biased ligand, was completely abrogated in β-arrestin knockout cells. These findings furnish novel insights into the intricate relationship between GPCR aggregation states and biased signaling, underscoring the pivotal role of molecular behaviors in guiding the development of selective therapeutic agents.
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Affiliation(s)
- Gege Qin
- Key Laboratory of Molecular Nanostructure and Nanotechnology, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jiachao Xu
- Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Yuxin Liang
- Key Laboratory of Molecular Nanostructure and Nanotechnology, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xiaohong Fang
- Key Laboratory of Molecular Nanostructure and Nanotechnology, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
- Hangzhou Institute of Medicine (HIM), Chinese Academy of Sciences, Hangzhou 310022, China
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37
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Madireddy A, Gerhardt J. Visualizing DNA replication by single-molecule analysis of replicated DNA. STAR Protoc 2023; 4:102721. [PMID: 38048218 PMCID: PMC10730367 DOI: 10.1016/j.xpro.2023.102721] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Revised: 07/10/2023] [Accepted: 10/30/2023] [Indexed: 12/06/2023] Open
Abstract
Single-molecule analysis of replicated DNA (SMARD) is a unique technique that enables visualization of DNA replication at specific genomic regions at single-molecule resolution. Here, we present a protocol for visualizing DNA replication by SMARD. We describe steps for pulse labeling DNA, followed by isolating and stretching of genomic DNA. We then detail the detection of the replication at chromosomal regions through immunostaining and fluorescence in situ hybridization. Using SMARD, we can visualize replication initiation, progression, termination, and fork stalling. For complete details on the use and execution of this protocol, please refer to Norio et al. (2001) and Gerhardt et al. (2014).1,2.
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Affiliation(s)
- Advaitha Madireddy
- Rutgers Cancer Institute of New Jersey, New Brunswick, NJ, USA; Department of Pediatrics Hematology/Oncology, Robert Wood Johnson Medical School, Rutgers University, New Brunswick, NJ, USA.
| | - Jeannine Gerhardt
- The Ronald O. Perelman and Claudia Cohen Center for Reproductive Medicine, Weill Cornell Medicine, New York, NY, USA; Department of Obstetrics and Gynecology, Weill Cornell Medicine, New York, NY, USA.
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38
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Zhu J, Zhang Q, Zhang H, Shi Z, Hu M, Bao C. A minority of final stacks yields superior amplitude in single-particle cryo-EM. Nat Commun 2023; 14:7822. [PMID: 38072910 PMCID: PMC10711021 DOI: 10.1038/s41467-023-43555-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Accepted: 11/13/2023] [Indexed: 12/18/2023] Open
Abstract
Cryogenic electron microscopy (cryo-EM) is widely used to determine near-atomic resolution structures of biological macromolecules. Due to the low signal-to-noise ratio, cryo-EM relies on averaging many images. However, a crucial question in the field of cryo-EM remains unanswered: how close can we get to the minimum number of particles required to reach a specific resolution in practice? The absence of an answer to this question has impeded progress in understanding sample behavior and the performance of sample preparation methods. To address this issue, we develop an iterative particle sorting and/or sieving method called CryoSieve. Extensive experiments demonstrate that CryoSieve outperforms other cryo-EM particle sorting algorithms, revealing that most particles are unnecessary in final stacks. The minority of particles remaining in the final stacks yield superior high-resolution amplitude in reconstructed density maps. For some datasets, the size of the finest subset approaches the theoretical limit.
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Affiliation(s)
- Jianying Zhu
- Yau Mathematical Sciences Center, Tsinghua University, Beijing, China
| | - Qi Zhang
- Key Laboratory of Protein Sciences (Tsinghua University), Ministry of Education, Beijing, China
- School of Life Science, Tsinghua University, Beijing, China
- Beijing Advanced Innovation Center for Structural Biology, Beijing, China
- Beijing Frontier Research Center for Biological Structure, Beijing, China
| | - Hui Zhang
- Qiuzhen College, Tsinghua University, Beijing, China
| | - Zuoqiang Shi
- Yau Mathematical Sciences Center, Tsinghua University, Beijing, China.
- Yanqi Lake Beijing Institute of Mathematical Sciences and Applications, Beijing, China.
| | - Mingxu Hu
- Key Laboratory of Protein Sciences (Tsinghua University), Ministry of Education, Beijing, China.
- School of Life Science, Tsinghua University, Beijing, China.
- Beijing Advanced Innovation Center for Structural Biology, Beijing, China.
- Beijing Frontier Research Center for Biological Structure, Beijing, China.
- Shenzhen Academy of Research and Translation, Shenzhen, China.
| | - Chenglong Bao
- Yau Mathematical Sciences Center, Tsinghua University, Beijing, China.
- Yanqi Lake Beijing Institute of Mathematical Sciences and Applications, Beijing, China.
- State Key Laboratory of Membrane Biology, School of Life Sciences, Tsinghua University, Beijing, China.
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39
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Huang R, Shi D. Treatment of noise caused by radiation damage during cryo-EM data collection. Structure 2023; 31:1523-1525. [PMID: 38065075 DOI: 10.1016/j.str.2023.11.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Revised: 11/10/2023] [Accepted: 11/11/2023] [Indexed: 12/18/2023]
Abstract
Here, we discuss how noise that is caused by radiation damage during cryo-EM data collections accumulates during single-particle analysis (SPA), MicroED, and cryo-ET. For MicroED and SPA, bad data can be identified and excluded during data collection and processing, whereas cryo-ET will require systematic radiation damage assessments that can be derived from SPA.
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Affiliation(s)
- Rick Huang
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892, USA
| | - Dan Shi
- Center for Structural Biology, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702, USA.
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40
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Sharma M, de Alba E. Assembly mechanism of the inflammasome sensor AIM2 revealed by single molecule analysis. Nat Commun 2023; 14:7957. [PMID: 38042863 PMCID: PMC10693601 DOI: 10.1038/s41467-023-43691-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Accepted: 11/06/2023] [Indexed: 12/04/2023] Open
Abstract
Pathogenic dsDNA prompts AIM2 assembly leading to the formation of the inflammasome, a multimeric complex that triggers the inflammatory response. The recognition of foreign dsDNA involves AIM2 self-assembly concomitant with dsDNA binding. However, we lack mechanistic and kinetic information on the formation and propagation of the assembly, which can shed light on innate immunity's time response and specificity. Combining optical traps and confocal fluorescence microscopy, we determine here the association and dissociation rates of the AIM2-DNA complex at the single molecule level. We identify distinct mechanisms for oligomer growth via the binding of incoming AIM2 molecules to adjacent dsDNA or direct interaction with bound AIM2 assemblies, resembling primary and secondary nucleation. Through these mechanisms, the size of AIM2 oligomers can increase fourfold in seconds. Finally, our data indicate that single AIM2 molecules do not diffuse/scan along the DNA, suggesting that oligomerization depends on stochastic encounters with DNA and/or DNA-bound AIM2.
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Affiliation(s)
- Meenakshi Sharma
- Department of Bioengineering, School of Engineering, University of California Merced, Merced, California, USA
| | - Eva de Alba
- Department of Bioengineering, School of Engineering, University of California Merced, Merced, California, USA.
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41
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Fernandez-Gimenez E, Carazo JM, Sorzano COS. Local defocus estimation in single particle analysis in cryo-electron microscopy. J Struct Biol 2023; 215:108030. [PMID: 37758154 DOI: 10.1016/j.jsb.2023.108030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2023] [Revised: 08/30/2023] [Accepted: 09/21/2023] [Indexed: 10/02/2023]
Abstract
Single Particle analysis (SPA) aims to determine the three-dimensional structure of proteins and macromolecular complexes. The current state of the art has allowed us to achieve near-atomic and even atomic resolutions. To obtain high-resolution structures, a set of well-defined image processing steps is required. A critical one is the estimation of the Contrast Transfer Function (CTF), which considers the sample defocus and aberrations of the microscope. Defocus is usually globally estimated; in this case, it is the same for all the particles in each micrograph. But proteins are ice-embedded at different heights, suggesting that defocus should be measured in a local (per particle) manner. There are four state-of-the-art programs to estimate local defocus (Gctf, Relion, CryoSPARC, and Xmipp). In this work, we have compared the results of these software packages to check whether the resolution improves. We have used the Scipion framework and developed a specific program to analyze local defocus. The results produced by different programs do not show a clear consensus using the current test datasets in this study.
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Affiliation(s)
- E Fernandez-Gimenez
- Centro Nac. Biotecnologia (CSIC), c/Darwin, 3, 28049 Cantoblanco, Madrid, Spain; Univ. Autonoma de Madrid, 28049 Cantoblanco, Madrid, Spain
| | - J M Carazo
- Centro Nac. Biotecnologia (CSIC), c/Darwin, 3, 28049 Cantoblanco, Madrid, Spain
| | - C O S Sorzano
- Centro Nac. Biotecnologia (CSIC), c/Darwin, 3, 28049 Cantoblanco, Madrid, Spain.
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42
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Huang C, Kim JS, Kirkland AI. Cryo-electron ptychography: Applications and potential in biological characterisation. Curr Opin Struct Biol 2023; 83:102730. [PMID: 37992450 DOI: 10.1016/j.sbi.2023.102730] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Revised: 09/06/2023] [Accepted: 10/16/2023] [Indexed: 11/24/2023]
Abstract
There is a clear need for developments in characterisation techniques that provide detailed information about structure-function relationships in biology. Using electron microscopy to achieve high resolution while maintaining a broad field of view remains a challenge, particularly for radiation-sensitive specimens where the signal-to-noise ratio required to maintain structural integrity is limited by low electron fluence. In this review, we explore the potential of cryogenic electron ptychography as an alternative method for characterising biological systems under low-fluence conditions. Using this method with increased information content from multiple sampled regions of interest potentially allows 3D reconstruction with far fewer particles than required in conventional cryo-electron microscopy. This is important for achieving higher resolution in systems where distributions of homogeneous single particles are difficult to obtain. We discuss the progress, limitations, and potential areas for future development of this approach for both single particle analysis and applications to heterogeneous large objects.
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Affiliation(s)
- Chen Huang
- Rosalind Franklin Institute, Harwell Science and Innovation Campus, Didcot, OX11 0QX, United Kingdom.
| | - Judy S Kim
- Rosalind Franklin Institute, Harwell Science and Innovation Campus, Didcot, OX11 0QX, United Kingdom; Department of Materials, University of Oxford, Oxford, OX1 3PH, United Kingdom
| | - Angus I Kirkland
- Rosalind Franklin Institute, Harwell Science and Innovation Campus, Didcot, OX11 0QX, United Kingdom; Department of Materials, University of Oxford, Oxford, OX1 3PH, United Kingdom
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43
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Fernández-Giménez E, Martínez MM, Marabini R, Strelak D, Sánchez-García R, Carazo JM, Sorzano COS. A new algorithm for particle weighted subtraction to decrease signals from unwanted components in single particle analysis. J Struct Biol 2023; 215:108024. [PMID: 37704013 DOI: 10.1016/j.jsb.2023.108024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Revised: 08/22/2023] [Accepted: 09/04/2023] [Indexed: 09/15/2023]
Abstract
Single particle analysis (SPA) in cryo-electron microscopy (cryo-EM) is highly used to obtain the near-atomic structure of biological macromolecules. The current methods allow users to produce high-resolution maps from many samples. However, there are still challenging cases that require extra processing to obtain high resolution. This is the case when the macromolecule of the sample is composed of different components and we want to focus just on one of them. For example, if the macromolecule is composed of several flexible subunits and we are interested in a specific one, if it is embedded in a viral capsid environment, or if it has additional components to stabilize it, such as nanodiscs. The signal from these components, which in principle we are not interested in, can be removed from the particles using a projection subtraction method. Currently, there are two projection subtraction methods used in practice and both have some limitations. In fact, after evaluating their results, we consider that the problem is still open to new solutions, as they do not fully remove the signal of the components that are not of interest. Our aim is to develop a new and more precise projection subtraction method, improving the performance of state-of-the-art methods. We tested our algorithm with data from public databases and an in-house data set. In this work, we show that the performance of our algorithm improves the results obtained by others, including the localization of small ligands, such as drugs, whose binding location is unknown a priori.
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Affiliation(s)
- E Fernández-Giménez
- Centro Nac. Biotecnología (CSIC), c/Darwin, 3, 28049 Cantoblanco, Madrid, Spain; Univ. Autonoma de Madrid, 28049 Cantoblanco, Madrid, Spain
| | - M M Martínez
- Centro Nac. Biotecnología (CSIC), c/Darwin, 3, 28049 Cantoblanco, Madrid, Spain
| | - R Marabini
- Centro Nac. Biotecnología (CSIC), c/Darwin, 3, 28049 Cantoblanco, Madrid, Spain; Univ. Autonoma de Madrid, 28049 Cantoblanco, Madrid, Spain
| | - D Strelak
- Institute of Computer Science, Masaryk University, Botanická 68a, 60200 Brno, Czech Republic
| | - R Sánchez-García
- Department of Statistics, University of Oxford, 24-29 St Giles', Oxford OX1 3LB, United Kingdom; Astex Pharmaceuticals, 436 Cambridge Science Park, Cambridge CB4 0QA, UK
| | - J M Carazo
- Centro Nac. Biotecnología (CSIC), c/Darwin, 3, 28049 Cantoblanco, Madrid, Spain
| | - C O S Sorzano
- Centro Nac. Biotecnología (CSIC), c/Darwin, 3, 28049 Cantoblanco, Madrid, Spain.
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44
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Zhang Y, Ge F, Lin X, Xue J, Song Y, Xie H, He Y. Extract latent features of single-particle trajectories with historical experience learning. Biophys J 2023; 122:4451-4466. [PMID: 37885178 PMCID: PMC10698327 DOI: 10.1016/j.bpj.2023.10.023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Revised: 07/30/2023] [Accepted: 10/20/2023] [Indexed: 10/28/2023] Open
Abstract
Single-particle tracking has enabled real-time, in situ quantitative studies of complex systems. However, inferring dynamic state changes from noisy and undersampling trajectories encounters challenges. Here, we introduce a data-driven method for extracting features of subtrajectories with historical experience learning (Deep-SEES), where a single-particle tracking analysis pipeline based on a self-supervised architecture automatically searches for the latent space, allowing effective segmentation of the underlying states from noisy trajectories without prior knowledge on the particle dynamics. We validated our method on a variety of noisy simulated and experimental data. Our results showed that the method can faithfully capture both stable states and their dynamic switch. In highly random systems, our method outperformed commonly used unsupervised methods in inferring motion states, which is important for understanding nanoparticles interacting with living cell membranes, active enzymes, and liquid-liquid phase separation. Self-generating latent features of trajectories could potentially improve the understanding, estimation, and prediction of many complex systems.
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Affiliation(s)
- Yongyu Zhang
- Department of Chemistry, Tsinghua University, Beijing, P.R. China
| | - Feng Ge
- Department of Chemistry, Tsinghua University, Beijing, P.R. China
| | - Xijian Lin
- Department of Chemistry, Tsinghua University, Beijing, P.R. China
| | - Jianfeng Xue
- Department of Chemistry, Tsinghua University, Beijing, P.R. China
| | - Yuxin Song
- Department of Chemistry, Tsinghua University, Beijing, P.R. China
| | - Hao Xie
- Department of Automation, Tsinghua University, Beijing, P.R. China.
| | - Yan He
- Department of Chemistry, Tsinghua University, Beijing, P.R. China.
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45
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George JT, Acree C, Park JU, Kong M, Wiegand T, Pignot YL, Kellogg EH, Greene EC, Sternberg SH. Mechanism of target site selection by type V-K CRISPR-associated transposases. Science 2023; 382:eadj8543. [PMID: 37972161 PMCID: PMC10771339 DOI: 10.1126/science.adj8543] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Accepted: 09/23/2023] [Indexed: 11/19/2023]
Abstract
CRISPR-associated transposases (CASTs) repurpose nuclease-deficient CRISPR effectors to catalyze RNA-guided transposition of large genetic payloads. Type V-K CASTs offer potential technology advantages but lack accuracy, and the molecular basis for this drawback has remained elusive. Here, we reveal that type V-K CASTs maintain an RNA-independent, "untargeted" transposition pathway alongside RNA-dependent integration, driven by the local availability of TnsC filaments. Using cryo-electron microscopy, single-molecule experiments, and high-throughput sequencing, we found that a minimal, CRISPR-less transpososome preferentially directs untargeted integration at AT-rich sites, with additional local specificity imparted by TnsB. By exploiting this knowledge, we suppressed untargeted transposition and increased type V-K CAST specificity up to 98.1% in cells without compromising on-target integration efficiency. These findings will inform further engineering of CAST systems for accurate, kilobase-scale genome engineering applications.
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Affiliation(s)
- Jerrin Thomas George
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA
| | - Christopher Acree
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA
| | - Jung-Un Park
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
| | - Muwen Kong
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA
| | - Tanner Wiegand
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA
| | - Yanis Luca Pignot
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA
| | - Elizabeth H. Kellogg
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
| | - Eric C. Greene
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA
| | - Samuel H. Sternberg
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA
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46
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Okura K, Matsumoto T, Narita A, Tatsumi H. Mechanical Stress Decreases the Amplitude of Twisting and Bending Fluctuations of Actin Filaments. J Mol Biol 2023; 435:168295. [PMID: 37783285 DOI: 10.1016/j.jmb.2023.168295] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Revised: 09/08/2023] [Accepted: 09/26/2023] [Indexed: 10/04/2023]
Abstract
A variety of biological roles of mechanical forces have been proposed in cell biology, such as cell signaling pathways for survival, development, growth, and differentiation. Mechanical forces alter the mechanical conditions within cells and their environment, which strongly influences the reorganization of the actin cytoskeleton. Single-molecule imaging studies of actin filaments have led to the hypothesis that the actin filament acts as a mechanosensor; e.g., increases in actin filament tension alter their conformation and affinity for regulatory proteins. However, our understanding of the molecular mechanisms underlying how tension modulates the mechanical behavior of a single actin filament is still incomplete. In this study, a direct measurement of the twisting and bending of a fluorescently labeled single actin filament under different tension levels by force application (0.8-3.4 pN) was performed using single-molecule fluorescence polarization (SMFP) microscopy. The results showed that the amplitude of twisting and bending fluctuations of a single actin filament decreased with increasing tension. Electron micrograph analysis of tensed filaments also revealed that the fluctuations in the crossover length of actin filaments decreased with increasing filament tension. Possible molecular mechanisms underlying these results involving the binding of actin-binding proteins, such as cofilin, to the filament are discussed.
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Affiliation(s)
- Kaoru Okura
- Department of Applied Bioscience, Kanazawa Institute of Technology, Ishikawa, Japan
| | - Tomoharu Matsumoto
- Department of Biological Science, Graduate School of Sciences, Nagoya University, 464-8601 Nagoya, Japan
| | - Akihiro Narita
- Department of Biological Science, Graduate School of Sciences, Nagoya University, 464-8601 Nagoya, Japan
| | - Hitoshi Tatsumi
- Department of Applied Bioscience, Kanazawa Institute of Technology, Ishikawa, Japan.
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47
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Langeberg CJ, Kieft JS. A generalizable scaffold-based approach for structure determination of RNAs by cryo-EM. Nucleic Acids Res 2023; 51:e100. [PMID: 37791881 PMCID: PMC10639074 DOI: 10.1093/nar/gkad784] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Revised: 08/31/2023] [Accepted: 09/24/2023] [Indexed: 10/05/2023] Open
Abstract
Single-particle cryo-electron microscopy (cryo-EM) can reveal the structures of large and often dynamic molecules, but smaller biomolecules (≤50 kDa) remain challenging targets due to their intrinsic low signal to noise ratio. Methods to help resolve small proteins have been applied but development of similar approaches to aid in structural determination of small, structured RNA elements have lagged. Here, we present a scaffold-based approach that we used to recover maps of sub-25 kDa RNA domains to 4.5-5.0 Å. While lacking the detail of true high-resolution maps, these maps are suitable for model building and preliminary structure determination. We demonstrate this method helped faithfully recover the structure of several RNA elements of known structure, and that it promises to be generalized to other RNAs without disturbing their native fold. This approach may streamline the sample preparation process and reduce the optimization required for data collection. This first-generation scaffold approach provides a robust system to aid in RNA structure determination by cryo-EM and lays the groundwork for further scaffold optimization to achieve higher resolution.
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Affiliation(s)
- Conner J Langeberg
- Department of Biochemistry and Molecular Genetics, Aurora, CO 80045, USA
| | - Jeffrey S Kieft
- Department of Biochemistry and Molecular Genetics, Aurora, CO 80045, USA
- RNA BioScience Initiative, University of Colorado Denver School of Medicine, Aurora, CO 80045, USA
- New York Structural Biology Center, New York, NY 10027, USA
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48
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He C, Wu CY, Li W, Xu K. Multidimensional Super-Resolution Microscopy Unveils Nanoscale Surface Aggregates in the Aging of FUS Condensates. J Am Chem Soc 2023; 145:24240-24248. [PMID: 37782826 PMCID: PMC10691933 DOI: 10.1021/jacs.3c08674] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/04/2023]
Abstract
The intracellular liquid-liquid phase separation (LLPS) of biomolecules gives rise to condensates that act as membrane-less organelles with vital functions. FUS, an RNA-binding protein, natively forms condensates through LLPS and further provides a model system for the often disease-linked liquid-to-solid transition of biomolecular condensates during aging. However, the mechanism of such maturation processes, as well as the structural and physical properties of the system, remains unclear, partly attributable to difficulties in resolving the internal structures of the micrometer-sized condensates with diffraction-limited optical microscopy. Harnessing a set of multidimensional super-resolution microscopy tools that uniquely map out local physicochemical parameters through single-molecule spectroscopy, here, we uncover nanoscale heterogeneities in FUS condensates and elucidate their evolution over aging. Through spectrally resolved single-molecule localization microscopy (SR-SMLM) with a solvatochromic dye, we unveil distinct hydrophobic nanodomains at the condensate surface. Through SMLM with a fluorogenic amyloid probe, we identify these nanodomains as amyloid aggregates. Through single-molecule displacement/diffusivity mapping (SMdM), we show that such nanoaggregates drastically impede local diffusion. Notably, upon aging or mechanical shears, these nanoaggregates progressively expand on the condensate surface, thus leading to a growing low-diffusivity shell while leaving the condensate interior diffusion-permitting. Together, beyond uncovering fascinating structural arrangements and aging mechanisms in the single-component FUS condensates, the demonstrated synergy of multidimensional super-resolution approaches in this study opens new paths for understanding LLPS systems at the nanoscale.
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Affiliation(s)
- Changdong He
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Chun Ying Wu
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Wan Li
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Ke Xu
- Department of Chemistry, University of California, Berkeley, California 94720, United States
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49
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Luo Z, Ni F, Wang Q, Ma J. OPUS-DSD: deep structural disentanglement for cryo-EM single-particle analysis. Nat Methods 2023; 20:1729-1738. [PMID: 37813988 PMCID: PMC10630141 DOI: 10.1038/s41592-023-02031-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Accepted: 08/24/2023] [Indexed: 10/11/2023]
Abstract
Cryo-electron microscopy (cryo-EM) captures snapshots of dynamic macromolecules, collectively illustrating the involved structural landscapes. This provides an exciting opportunity to explore the structural variations of macromolecules under study. However, traditional cryo-EM single-particle analysis often yields static structures. Here we describe OPUS-DSD, an algorithm capable of efficiently reconstructing the structural landscape embedded in cryo-EM data. OPUS-DSD uses a three-dimensional convolutional encoder-decoder architecture trained with cryo-EM images, thereby encoding structural variations into a smooth and easily analyzable low-dimension space. This space can be traversed to reconstruct continuous dynamics or clustered to identify distinct conformations. OPUS-DSD can offer meaningful insights into the structural variations of macromolecules, filling in the gaps left by traditional cryo-EM structural determination, and potentially improves the reconstruction resolution by reliably clustering similar particles within the dataset. These functionalities are especially relevant to the study of highly dynamic biological systems. OPUS-DSD is available at https://github.com/alncat/opusDSD .
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Affiliation(s)
- Zhenwei Luo
- Multiscale Research Institute of Complex Systems, Fudan University, Shanghai, China
- Zhangjiang Fudan International Innovation Center, Fudan University, Shanghai, China
- Shanghai AI Laboratory, Shanghai, China
| | - Fengyun Ni
- Multiscale Research Institute of Complex Systems, Fudan University, Shanghai, China
| | - Qinghua Wang
- Center for Biomolecular Innovation, Harcam Biomedicines, Shanghai, China
| | - Jianpeng Ma
- Multiscale Research Institute of Complex Systems, Fudan University, Shanghai, China.
- Zhangjiang Fudan International Innovation Center, Fudan University, Shanghai, China.
- Shanghai AI Laboratory, Shanghai, China.
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50
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Heemskerk T, van de Kamp G, Essers J, Kanaar R, Paul MW. Multi-scale cellular imaging of DNA double strand break repair. DNA Repair (Amst) 2023; 131:103570. [PMID: 37734176 DOI: 10.1016/j.dnarep.2023.103570] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2023] [Revised: 09/08/2023] [Accepted: 09/11/2023] [Indexed: 09/23/2023]
Abstract
Live-cell and high-resolution fluorescence microscopy are powerful tools to study the organization and dynamics of DNA double-strand break repair foci and specific repair proteins in single cells. This requires specific induction of DNA double-strand breaks and fluorescent markers to follow the DNA lesions in living cells. In this review, where we focused on mammalian cell studies, we discuss different methods to induce DNA double-strand breaks, how to visualize and quantify repair foci in living cells., We describe different (live-cell) imaging modalities that can reveal details of the DNA double-strand break repair process across multiple time and spatial scales. In addition, recent developments are discussed in super-resolution imaging and single-molecule tracking, and how these technologies can be applied to elucidate details on structural compositions or dynamics of DNA double-strand break repair.
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Affiliation(s)
- Tim Heemskerk
- Department of Molecular Genetics, Oncode Institute, Erasmus MC Cancer Institute, Erasmus University Medical Center, Rotterdam, the Netherlands
| | - Gerarda van de Kamp
- Department of Molecular Genetics, Oncode Institute, Erasmus MC Cancer Institute, Erasmus University Medical Center, Rotterdam, the Netherlands
| | - Jeroen Essers
- Department of Molecular Genetics, Oncode Institute, Erasmus MC Cancer Institute, Erasmus University Medical Center, Rotterdam, the Netherlands; Department of Vascular Surgery, Erasmus University Medical Center, Rotterdam, the Netherlands; Department of Radiotherapy, Erasmus MC Cancer Institute, Erasmus University Medical Center, Rotterdam, the Netherlands
| | - Roland Kanaar
- Department of Molecular Genetics, Oncode Institute, Erasmus MC Cancer Institute, Erasmus University Medical Center, Rotterdam, the Netherlands
| | - Maarten W Paul
- Department of Molecular Genetics, Oncode Institute, Erasmus MC Cancer Institute, Erasmus University Medical Center, Rotterdam, the Netherlands.
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