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Margheritis E, Kappelhoff S, Cosentino K. Pore-Forming Proteins: From Pore Assembly to Structure by Quantitative Single-Molecule Imaging. Int J Mol Sci 2023; 24:ijms24054528. [PMID: 36901959 PMCID: PMC10003378 DOI: 10.3390/ijms24054528] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Revised: 02/11/2023] [Accepted: 02/21/2023] [Indexed: 03/03/2023] Open
Abstract
Pore-forming proteins (PFPs) play a central role in many biological processes related to infection, immunity, cancer, and neurodegeneration. A common feature of PFPs is their ability to form pores that disrupt the membrane permeability barrier and ion homeostasis and generally induce cell death. Some PFPs are part of the genetically encoded machinery of eukaryotic cells that are activated against infection by pathogens or in physiological programs to carry out regulated cell death. PFPs organize into supramolecular transmembrane complexes that perforate membranes through a multistep process involving membrane insertion, protein oligomerization, and finally pore formation. However, the exact mechanism of pore formation varies from PFP to PFP, resulting in different pore structures with different functionalities. Here, we review recent insights into the molecular mechanisms by which PFPs permeabilize membranes and recent methodological advances in their characterization in artificial and cellular membranes. In particular, we focus on single-molecule imaging techniques as powerful tools to unravel the molecular mechanistic details of pore assembly that are often obscured by ensemble measurements, and to determine pore structure and functionality. Uncovering the mechanistic elements of pore formation is critical for understanding the physiological role of PFPs and developing therapeutic approaches.
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Mazumder A, Mozammal M, Talukder MA. Three-dimensional imaging of biological cells using surface plasmon coupled emission. JOURNAL OF BIOMEDICAL OPTICS 2022; 27:106002. [PMID: 36203237 PMCID: PMC9535299 DOI: 10.1117/1.jbo.27.10.106002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Accepted: 09/13/2022] [Indexed: 06/16/2023]
Abstract
SIGNIFICANCE Biological cell imaging has become one of the most crucial research interests because of its applications in biomedical and microbiology studies. However, three-dimensional (3D) imaging of biological cells is critically challenging and often involves prohibitively expensive and complex equipment. Therefore, a low-cost imaging technique with a simpler optical arrangement is immensely needed. AIM The proposed approach will provide an accurate cell image at a low cost without needing any microscope or extensive processing of the collected data, often used in conventional imaging techniques. APPROACH We propose that patterns of surface plasmon coupled emission (SPCE) features from a fluorescently labeled biological cell can be used to image the cell. An imaging methodology has been developed and theoretically demonstrated to create 3D images of cells from the detected SPCE patterns. The 3D images created from the different SPCE properties at the far-field closely match the actual cell structures. RESULTS The developed technique has been applied to different regular and irregular cell shapes. In each case, the calculated root-mean-square error (RMSE) of the created images from the cell structures remains within a few percentages. Our work recreates the base of a circular-shaped cell with an RMSE of ≲1.4 % . In addition, the images of irregular-shaped cell bases have an RMSE of ≲2.8 % . Finally, we obtained a 3D image with an RMSE of ≲6.5 % for a random cellular structure. CONCLUSIONS Despite being in its initial stage of development, the proposed technique shows promising results considering its simplicity and the nominal cost it would require.
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Affiliation(s)
- Anik Mazumder
- Bangladesh University of Engineering and Technology, Department of Electrical and Electronic Engineering, Dhaka, Bangladesh
- United International University, Department of Computer Science and Engineering, Dhaka, Bangladesh
| | - Mohammad Mozammal
- Bangladesh University of Engineering and Technology, Department of Electrical and Electronic Engineering, Dhaka, Bangladesh
| | - Muhammad Anisuzzaman Talukder
- Bangladesh University of Engineering and Technology, Department of Electrical and Electronic Engineering, Dhaka, Bangladesh
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Jang E, Ghaffari S, Lee WL. Quantifying Endothelial Transcytosis with Total Internal Reflection Fluorescence Microscopy (TIRF). Methods Mol Biol 2022; 2440:115-124. [PMID: 35218536 DOI: 10.1007/978-1-0716-2051-9_7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Apical-to-basal transcytosis by endothelial cells can be visualized and quantified using total internal reflection fluorescence (TIRF) microscopy of the basal membrane. Past techniques to study transcytosis including electron microscopy and transwells have several limitations such as confounding from paracellular leakage, low transfection efficiency, and the largely descriptive nature of electron microscopy. After the addition of a fluorescent ligand to the apical endothelial surface, using TIRF to measure exocytosis at the basal membrane bypasses these issues by studying transcytosis across a single cell of a confluent endothelial monolayer in real time. A major benefit of TIRF is that only a small volume of the cell is illuminated, thus greatly reducing background noise from the overlying cytosol in the images. This protocol outlines the steps to image and quantify exocytosis of apically applied fluorophore-tagged low-density lipoprotein (LDL) using TIRF microscopy and MATLAB. A similar approach can be used to study endothelial transcytosis of other ligands such as albumin or high-density lipoprotein.
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Affiliation(s)
- Erika Jang
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada
| | - Siavash Ghaffari
- Keenan Centre for Biomedical Research, St. Michael's Hospital, Toronto, ON, Canada
| | - Warren L Lee
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada.
- Keenan Centre for Biomedical Research, St. Michael's Hospital, Toronto, ON, Canada.
- Departments of Biochemistry, Medicine and the Interdepartmental Division of Critical Care, University of Toronto, Toronto, ON, Canada.
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Fairlamb MS, Whitaker AM, Bain FE, Spies M, Freudenthal BD. Construction of a Three-Color Prism-Based TIRF Microscope to Study the Interactions and Dynamics of Macromolecules. BIOLOGY 2021; 10:biology10070571. [PMID: 34201434 PMCID: PMC8301196 DOI: 10.3390/biology10070571] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Revised: 06/08/2021] [Accepted: 06/15/2021] [Indexed: 02/05/2023]
Abstract
Simple Summary Prism-based single-molecule total internal reflection fluorescence (prismTIRF) microscopes are excellent tools for studying macromolecular dynamics and interactions. Here, we provide an easy-to-follow guide for the design, assembly, and operation of a three-color prismTIRF microscope using commercially available components with the hope of assisting those who aim to implement TIRF imaging techniques in their laboratory. Abstract Single-molecule total internal reflection fluorescence (TIRF) microscopy allows for the real-time visualization of macromolecular dynamics and complex assembly. Prism-based TIRF microscopes (prismTIRF) are relatively simple to operate and can be easily modulated to fit the needs of a wide variety of experimental applications. While building a prismTIRF microscope without expert assistance can pose a significant challenge, the components needed to build a prismTIRF microscope are relatively affordable and, with some guidance, the assembly can be completed by a determined novice. Here, we provide an easy-to-follow guide for the design, assembly, and operation of a three-color prismTIRF microscope which can be utilized for the study of macromolecular complexes, including the multi-component protein–DNA complexes responsible for DNA repair, replication, and transcription. Our hope is that this article can assist laboratories that aspire to implement single-molecule TIRF techniques, and consequently expand the application of this technology.
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Affiliation(s)
- Max S. Fairlamb
- Department of Biochemistry and Molecular Biology and Department of Cancer Biology, University of Kansas Medical Center, Kansas City, KS 66160, USA; (M.S.F.); (A.M.W.)
| | - Amy M. Whitaker
- Department of Biochemistry and Molecular Biology and Department of Cancer Biology, University of Kansas Medical Center, Kansas City, KS 66160, USA; (M.S.F.); (A.M.W.)
| | - Fletcher E. Bain
- Department of Biochemistry and Molecular Biology, University of Iowa Carver College of Medicine, 51 Newton Road, Iowa City, IA 52242, USA; (F.E.B.); (M.S.)
| | - Maria Spies
- Department of Biochemistry and Molecular Biology, University of Iowa Carver College of Medicine, 51 Newton Road, Iowa City, IA 52242, USA; (F.E.B.); (M.S.)
| | - Bret D. Freudenthal
- Department of Biochemistry and Molecular Biology and Department of Cancer Biology, University of Kansas Medical Center, Kansas City, KS 66160, USA; (M.S.F.); (A.M.W.)
- Correspondence:
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Gibbs DR, Kaur A, Megalathan A, Sapkota K, Dhakal S. Build Your Own Microscope: Step-By-Step Guide for Building a Prism-Based TIRF Microscope. Methods Protoc 2018; 1:mps1040040. [PMID: 31164580 PMCID: PMC6481079 DOI: 10.3390/mps1040040] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2018] [Revised: 10/31/2018] [Accepted: 10/31/2018] [Indexed: 01/09/2023] Open
Abstract
Prism-based total internal reflection fluorescence (pTIRF) microscopy is one of the most widely used techniques for the single molecule analysis of a vast range of samples including biomolecules, nanostructures, and cells, to name a few. It allows for excitation of surface bound molecules/particles/quantum dots via evanescent field of a confined region of space, which is beneficial not only for single molecule detection but also for analysis of single molecule dynamics and for acquiring kinetics data. However, there is neither a commercial microscope available for purchase nor a detailed guide dedicated for building this microscope. Thus far, pTIRF microscopes are custom-built with the use of a commercially available inverted microscope, which requires high level of expertise in selecting and handling sophisticated instrument-parts. To directly address this technology gap, here we describe a step-by-step guide on how to build and characterize a pTIRF microscope for in vitro single-molecule imaging, nanostructure analysis and other life sciences research.
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Affiliation(s)
- Dalton R Gibbs
- Department of Chemistry, Virginia Commonwealth University, 1001 West Main Street, Richmond, VA 23284, USA.
| | - Anisa Kaur
- Department of Chemistry, Virginia Commonwealth University, 1001 West Main Street, Richmond, VA 23284, USA.
| | - Anoja Megalathan
- Department of Chemistry, Virginia Commonwealth University, 1001 West Main Street, Richmond, VA 23284, USA.
| | - Kumar Sapkota
- Department of Chemistry, Virginia Commonwealth University, 1001 West Main Street, Richmond, VA 23284, USA.
| | - Soma Dhakal
- Department of Chemistry, Virginia Commonwealth University, 1001 West Main Street, Richmond, VA 23284, USA.
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Effect of human cytomegalovirus (HCMV) US27 on CXCR4 receptor internalization measured by fluorogen-activating protein (FAP) biosensors. PLoS One 2017; 12:e0172042. [PMID: 28207860 PMCID: PMC5313195 DOI: 10.1371/journal.pone.0172042] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Accepted: 01/30/2017] [Indexed: 01/08/2023] Open
Abstract
Human cytomegalovirus (HCMV) is a widespread pathogen and a member of the Herpesviridae family. HCMV has a large genome that encodes many genes that are non-essential for virus replication but instead play roles in manipulation of the host immune environment. One of these is the US27 gene, which encodes a protein with homology to the chemokine receptor family of G protein-coupled receptors (GPCRs). The US27 protein has no known chemokine ligands but can modulate the signaling activity of host receptor CXCR4. We investigated the mechanism for enhanced CXCR4 signaling in the presence of US27 using a novel biosensor system comprised of fluorogen activating proteins (FAPs). FAP-tagged CXCR4 and US27 were used to explore receptor internalization and recovery dynamics, and the results demonstrate that significantly more CXCR4 internalization was observed in the presence of US27 compared to CXCR4 alone upon stimulation with CXCL12. While ligand-induced endocytosis rates were higher, steady state internalization of CXCR4 was not affected by US27. Additionally, US27 underwent rapid endocytosis at a rate that was independent of either CXCR4 expression or CXCL12 stimulation. These results demonstrate that one mechanism by which US27 can enhance CXCR4 signaling is to alter receptor internalization dynamics, which could ultimately have the effect of promoting virus dissemination by increasing trafficking of HCMV-infected cells to tissues where CXCL12 is highly expressed.
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Itofusa R, Tojima T, Kamiguchi H. Visualization of Clathrin-Mediated Endocytosis During Semaphorin-Guided Axonal Growth. Methods Mol Biol 2017; 1493:287-298. [PMID: 27787859 DOI: 10.1007/978-1-4939-6448-2_21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Semaphorin3A (Sema3A) guides axonal growth during neuronal network development. Accumulating evidence indicates that Sema3A-induced growth cone collapse and repulsion involve endocytic membrane trafficking in the growth cone. It is now possible to visualize endocytic processes in living cells using total internal reflection fluorescence microscopy (TIRFM), a powerful tool for imaging dynamic subcellular events at the plasma membrane. In this chapter, we describe a method for TIRFM observation and analysis of clathrin-mediated endocytosis in growth cones of chicken dorsal root ganglion neurons that receive an extracellular concentration gradient of Sema3A in a culture medium.
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Affiliation(s)
- Rurika Itofusa
- Laboratory for Neuronal Growth Mechanisms, RIKEN Brain Science Institute, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan
| | - Takuro Tojima
- Laboratory for Neuronal Growth Mechanisms, RIKEN Brain Science Institute, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan
- PRESTO, Japan Science and Technology Agency, 4-1-8 Honcho, Kawaguchi, Saitama, 332-0012, Japan
| | - Hiroyuki Kamiguchi
- Laboratory for Neuronal Growth Mechanisms, RIKEN Brain Science Institute, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan.
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Kisler K, Dominguez R. Live-Cell Imaging of the Estrogen Receptor by Total Internal Reflection Fluorescence Microscopy. Methods Mol Biol 2016; 1366:175-187. [PMID: 26585135 DOI: 10.1007/978-1-4939-3127-9_14] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Trafficking studies of plasma membrane-localized intracellular estrogen receptors have mainly relied on biochemical and histological techniques to locate the receptor before and after estradiol stimulation. More often than not these experiments were performed using postmortem, lysed, or fixed tissue samples, whose tissue or cellular structure is typically severely altered or at times completely lost, making the definitive localization of estrogen receptors difficult to ascertain. To overcome this limitation we began using total internal reflection fluorescence microscopy (TIRFM) to study the trafficking of plasma membrane estrogen receptors. This real-time imaging approach, described in this chapter, permits observation of live, intact cells while allowing visualization of the steps (in time and spatial distribution) involved in receptor activation by estradiol and movements on and near the membrane. TIRFM yields high-contrast real-time images of fluorescently labeled E6BSA molecules on and just below the cell surface and is ideal for studying estrogen receptor trafficking in living cells.
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Affiliation(s)
- Kassandra Kisler
- Department of Physiology and Biophysics, and the Zilkha Neurogenetic Institute, Keck School of Medicine of the University of Southern California, 1501 San Pablo St., ZNI 323, Los Angeles, CA, 90033, USA
| | - Reymundo Dominguez
- Department of Physiology and Biophysics, Keck Schoolof Medicine of the University of Southern California, Los Angeles, CA, USA.
- The Zilkha Neurogenetic Institute, Keck School of Medicine of the University of Southern California, Los Angeles, CA, USA.
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9
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Abstract
Total internal reflection fluorescence (TIRF) microscopy is a powerful tool for visualizing near-membrane cellular structures and processes, including imaging of local Ca2+ transients with single-channel resolution. TIRF is most commonly implemented in epi-fluorescence mode, whereby laser excitation light is introduced at a spot near the periphery of the back focal plane of a high numerical aperture objective lens. However, this approach results in an irregular illumination field, owing to interference fringes and scattering and shadowing by cellular structures. We describe a simple system to circumvent these limitations, utilizing a pair of galvanometer-driven mirrors to rapidly spin the laser spot in a circle at the back focal plane of the objective lens, so that irregularities average out during each camera exposure to produce an effectively uniform field. Computer control of the mirrors enables precise scanning at 200 Hz (5ms camera exposure times) or faster, and the scan radius can be altered on a frame-by-frame basis to achieve near-simultaneous imaging in TIRF, widefield and ‘skimming plane’ imaging modes. We demonstrate the utility of the system for dynamic recording of local inositol trisphosphate-mediated Ca2+ signals and for imaging the redistribution of STIM and Orai proteins during store-operated Ca2+ entry. We further anticipate that it will be readily applicable for numerous other near-membrane studies, especially those involving fast dynamic processes.
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10
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The physical basis of total internal reflection fluorescence (TIRF) microscopy and its cellular applications. Methods Mol Biol 2015; 1251:1-23. [PMID: 25391791 DOI: 10.1007/978-1-4939-2080-8_1] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Total internal reflection fluorescence (TIRF) microscopy has gained popularity in recent years among cell biologists due to its ability to clearly visualize events that occur at the adherent plasma membrane of cells. TIRF microscopy systems are now commercially available from nearly all microscope suppliers. This review aims to give the reader an introduction to the physical basis of TIRF and considerations that need to be made when purchasing a commercial system. We explain how TIRF can be combined with other microscopy modalities and describe how to use TIRF to study processes such as endocytosis, exocytosis, and focal adhesion dynamics. Finally, we provide a step-by-step guide to imaging and analyzing focal adhesion dynamics in a migrating cell using TIRF microscopy.
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11
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Bücherl CA, Bader A, Westphal AH, Laptenok SP, Borst JW. FRET-FLIM applications in plant systems. PROTOPLASMA 2014; 251:383-394. [PMID: 24390247 DOI: 10.1007/s00709-013-0595-7] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2013] [Accepted: 12/05/2013] [Indexed: 05/28/2023]
Abstract
A hallmark of cellular processes is the spatio-temporally regulated interplay of biochemical components. Assessing spatial information of molecular interactions within living cells is difficult using traditional biochemical methods. Developments in green fluorescent protein technology in combination with advances in fluorescence microscopy have revolutionised this field of research by providing the genetic tools to investigate the spatio-temporal dynamics of biomolecules in live cells. In particular, fluorescence lifetime imaging microscopy (FLIM) has become an inevitable technique for spatially resolving cellular processes and physical interactions of cellular components in real time based on the detection of Förster resonance energy transfer (FRET). In this review, we provide a theoretical background of FLIM as well as FRET-FLIM analysis. Furthermore, we show two cases in which advanced microscopy applications revealed many new insights of cellular processes in living plant cells as well as in whole plants.
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Chapman NM, Connolly SF, Reinl EL, Houtman JCD. Focal adhesion kinase negatively regulates Lck function downstream of the T cell antigen receptor. THE JOURNAL OF IMMUNOLOGY 2013; 191:6208-21. [PMID: 24227778 DOI: 10.4049/jimmunol.1301587] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Focal adhesion kinase (FAK) is a critical regulator of signal transduction in multiple cell types. Although this protein is activated upon TCR engagement, the cellular function that FAK plays in mature human T cells is unknown. By suppressing the function of FAK, we revealed that FAK inhibits TCR-mediated signaling by recruiting C-terminal Src kinase to the membrane and/or receptor complex following TCR activation. Thus, in the absence of FAK, the inhibitory phosphorylation of Lck and/or Fyn is impaired. Together, these data highlight a novel role for FAK as a negative regulator TCR function in human T cells. These results also suggest that changes in FAK expression could modulate sensitivity to TCR stimulation and contribute to the progression of T cell malignancies and autoimmune diseases.
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Affiliation(s)
- Nicole M Chapman
- Interdisciplinary Graduate Program in Immunology, University of Iowa, Iowa City, IA 52242
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Chiba K, Shimada Y, Kinjo M, Suzuki T, Uchida S. Simple and direct assembly of kymographs from movies using KYMOMAKER. Traffic 2013; 15:1-11. [PMID: 24102769 DOI: 10.1111/tra.12127] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2013] [Revised: 09/25/2013] [Accepted: 10/01/2013] [Indexed: 01/13/2023]
Abstract
In tracking analysis, the movement of cargos by motor proteins in axons is often represented by a time-space plot termed a 'kymograph'. Manual creation of kymographs is time-consuming and complicated for cell biologists. Therefore, we developed KYMOMAKER, a simple system that automatically creates a kymograph from a movie without generating multiple time-dissected movie stacks. In addition, KYMOMAKER can automatically extract faint vesicle traces, and can thereby effectively analyze cargos expressed at low levels in axons. A filter can be applied to remove traces of non-physiological movements and to extract meaningful traces of anterograde or retrograde cargo transport. For example, only cargos that move at a speed of >0.4 µm/second for a distance of >1 µm can be included. Another function of KYMOMAKER is to create a color kymograph in which the color of the trace varies according to the position of the fluorescent particle in the axis perpendicular to the long axis of the axon. Such positional information is completely lost in conventional kymographs. KYMOMAKER is an open access program that can be easily used to analyze vesicle transport in axons by cell biologists who do not have specific knowledge of bioimage informatics.
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Affiliation(s)
- Kyoko Chiba
- Laboratory of Neuroscience, Graduate School of Pharmaceutical Sciences, Hokkaido University, Sapporo, 060-0812, Japan
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Otterstrom J, van Oijen AM. Visualization of membrane fusion, one particle at a time. Biochemistry 2013; 52:1654-68. [PMID: 23421412 DOI: 10.1021/bi301573w] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Protein-mediated fusion between phospholipid bilayers is a fundamental and necessary mechanism for many cellular processes. The short-lived nature of the intermediate states visited during fusion makes it challenging to capture precise kinetic information using classical, ensemble-averaging biophysical techniques. Recently, a number of single-particle fluorescence microscopy-based assays that allow researchers to obtain highly quantitative data about the fusion process by observing individual fusion events in real time have been developed. These assays depend upon changes in the acquired fluorescence signal to provide a direct readout for transitions between the various fusion intermediates. The resulting data yield meaningful and detailed kinetic information about the transitory states en route to productive membrane fusion. In this review, we highlight recent in vitro and in vivo studies of membrane fusion at the single-particle level in the contexts of viral membrane fusion and SNARE-mediated synaptic vesicle fusion. These studies afford insight into mechanisms of coordination between fusion-mediating proteins as well as coordination of the overall fusion process with other cellular processes. The development of single-particle approaches to investigate membrane fusion and their successful application to a number of model systems have resulted in a new experimental paradigm and open up considerable opportunities to extend these methods to other biological processes that involve membrane fusion.
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Affiliation(s)
- Jason Otterstrom
- Harvard Biophysics Program, Harvard Medical School , 240 Longwood Avenue, Boston, Massachusetts 02115, United States
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