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Senapati S, Park PSH. Understanding the Rhodopsin Worldview Through Atomic Force Microscopy (AFM): Structure, Stability, and Activity Studies. CHEM REC 2023; 23:e202300113. [PMID: 37265335 PMCID: PMC10908267 DOI: 10.1002/tcr.202300113] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Revised: 05/12/2023] [Indexed: 06/03/2023]
Abstract
Rhodopsin is a G protein-coupled receptor (GPCR) present in the rod outer segment (ROS) of photoreceptor cells that initiates the phototransduction cascade required for scotopic vision. Due to the remarkable advancements in technological tools, the chemistry of rhodopsin has begun to unravel especially over the past few decades, but mostly at the ensemble scale. Atomic force microscopy (AFM) is a tool capable of providing critical information from a single-molecule point of view. In this regard, to bolster our understanding of rhodopsin at the nanoscale level, AFM-based imaging, force spectroscopy, and nano-indentation techniques were employed on ROS disc membranes containing rhodopsin, isolated from vertebrate species both in normal and diseased states. These AFM studies on samples from native retinal tissue have provided fundamental insights into the structure and function of rhodopsin under normal and dysfunctional states. We review here the findings from these AFM studies that provide important insights on the supramolecular organization of rhodopsin within the membrane and factors that contribute to this organization, the molecular interactions stabilizing the structure of the receptor and factors that can modify those interactions, and the mechanism underlying constitutive activity in the receptor that can cause disease.
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Affiliation(s)
- Subhadip Senapati
- Department of Ophthalmology and Visual Sciences, Case Western Reserve University, Cleveland, OH 44106, USA
- Prayoga Institute of Education Research, Bengaluru, KA 560116, India
| | - Paul S-H Park
- Department of Ophthalmology and Visual Sciences, Case Western Reserve University, Cleveland, OH 44106, USA
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2
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Lachaize V, Peña B, Ciubotaru C, Cojoc D, Chen SN, Taylor MRG, Mestroni L, Sbaizero O. Compromised Biomechanical Properties, Cell-Cell Adhesion and Nanotubes Communication in Cardiac Fibroblasts Carrying the Lamin A/C D192G Mutation. Int J Mol Sci 2021; 22:9193. [PMID: 34502098 PMCID: PMC8431729 DOI: 10.3390/ijms22179193] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Revised: 08/03/2021] [Accepted: 08/05/2021] [Indexed: 11/16/2022] Open
Abstract
Clinical effects induced by arrhythmogenic cardiomyopathy (ACM) originate from a large spectrum of genetic variations, including the missense mutation of the lamin A/C gene (LMNA), LMNA D192G. The aim of our study was to investigate the biophysical and biomechanical impact of the LMNA D192G mutation on neonatal rat ventricular fibroblasts (NRVF). The main findings in mutated NRVFs were: (i) cytoskeleton disorganization (actin and intermediate filaments); (ii) decreased elasticity of NRVFs; (iii) altered cell-cell adhesion properties, that highlighted a strong effect on cellular communication, in particular on tunneling nanotubes (TNTs). In mutant-expressing fibroblasts, these nanotubes were weakened with altered mechanical properties as shown by atomic force microscopy (AFM) and optical tweezers. These outcomes complement prior investigations on LMNA mutant cardiomyocytes and suggest that the LMNA D192G mutation impacts the biomechanical properties of both cardiomyocytes and cardiac fibroblasts. These observations could explain how this mutation influences cardiac biomechanical pathology and the severity of ACM in LMNA-cardiomyopathy.
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Affiliation(s)
- Veronique Lachaize
- Department of Engineering and Architecture, University of Trieste, Via Valerio 10, 34127 Trieste, Italy;
| | - Brisa Peña
- CU-Cardiovascular Institute, University of Colorado Anschutz Medical Campus, 12700 E. 19th Ave., Aurora, CO 80045, USA; (B.P.); (S.N.C.); (M.R.G.T.); (L.M.)
- Consortium for Fibrosis Research & Translation, Anschutz Medical Campus, University of Colorado, 12700 E. 19th Ave., Aurora, CO 80045, USA
- Bioengineering Department, University of Colorado Denver Anschutz Medical Campus, Bioscience 2 1270 E. Montview Ave., Suite 100, Aurora, CO 80045, USA
| | - Catalin Ciubotaru
- Institute of Materials, National Research Council of Italy (CNR_IOM), Area Science Park Basovizza, 34149 Trieste, Italy; (C.C.); (D.C.)
| | - Dan Cojoc
- Institute of Materials, National Research Council of Italy (CNR_IOM), Area Science Park Basovizza, 34149 Trieste, Italy; (C.C.); (D.C.)
| | - Suet Nee Chen
- CU-Cardiovascular Institute, University of Colorado Anschutz Medical Campus, 12700 E. 19th Ave., Aurora, CO 80045, USA; (B.P.); (S.N.C.); (M.R.G.T.); (L.M.)
| | - Matthew R. G. Taylor
- CU-Cardiovascular Institute, University of Colorado Anschutz Medical Campus, 12700 E. 19th Ave., Aurora, CO 80045, USA; (B.P.); (S.N.C.); (M.R.G.T.); (L.M.)
| | - Luisa Mestroni
- CU-Cardiovascular Institute, University of Colorado Anschutz Medical Campus, 12700 E. 19th Ave., Aurora, CO 80045, USA; (B.P.); (S.N.C.); (M.R.G.T.); (L.M.)
| | - Orfeo Sbaizero
- Department of Engineering and Architecture, University of Trieste, Via Valerio 10, 34127 Trieste, Italy;
- CU-Cardiovascular Institute, University of Colorado Anschutz Medical Campus, 12700 E. 19th Ave., Aurora, CO 80045, USA; (B.P.); (S.N.C.); (M.R.G.T.); (L.M.)
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3
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Koehler M, Lo Giudice C, Vogl P, Ebner A, Hinterdorfer P, Gruber HJ, Alsteens D. Control of Ligand-Binding Specificity Using Photocleavable Linkers in AFM Force Spectroscopy. NANO LETTERS 2020; 20:4038-4042. [PMID: 32320256 PMCID: PMC7252943 DOI: 10.1021/acs.nanolett.0c01426] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Revised: 04/21/2020] [Indexed: 05/26/2023]
Abstract
In recent decades, atomic force microscopy (AFM), in particular the force spectroscopy mode, has become a method of choice to study biomolecular interactions at the single-molecule level. However, grafting procedures as well as determining binding specificity remain challenging. We report here an innovative approach based on a photocleavable group that enables in situ release of the ligands bound to the AFM tip and thus allows direct assessment of the binding specificity. Applicable to a wide variety of molecules, the strategy presented here provides new opportunities to study specific interactions and deliver single molecules with high spatiotemporal resolution in a wide range of applications, including AFM-based cell biology.
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Affiliation(s)
- Melanie Koehler
- Louvain
Institute of Biomolecular Science and Technology, Université Catholique de Louvain, 1348 Louvain-la-Neuve, Belgium
| | - Cristina Lo Giudice
- Louvain
Institute of Biomolecular Science and Technology, Université Catholique de Louvain, 1348 Louvain-la-Neuve, Belgium
| | - Philipp Vogl
- Institute
of Biophysics, Johannes Kepler University, 4020 Linz, Austria
| | - Andreas Ebner
- Institute
of Biophysics, Johannes Kepler University, 4020 Linz, Austria
| | | | - Hermann J. Gruber
- Institute
of Biophysics, Johannes Kepler University, 4020 Linz, Austria
| | - David Alsteens
- Louvain
Institute of Biomolecular Science and Technology, Université Catholique de Louvain, 1348 Louvain-la-Neuve, Belgium
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4
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Bashant KR, Toepfner N, Day CJ, Mehta NN, Kaplan MJ, Summers C, Guck J, Chilvers ER. The mechanics of myeloid cells. Biol Cell 2020; 112:103-112. [DOI: 10.1111/boc.201900084] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Revised: 12/18/2019] [Accepted: 01/03/2020] [Indexed: 01/05/2023]
Affiliation(s)
- Kathleen R Bashant
- Department of MedicineUniversity of Cambridge Cambridge UK
- Systemic Autoimmunity BranchNational Institute of Arthritis and Musculoskeletal and Skin DiseasesNational Institutes of Health Bethesda Maryland USA
| | - Nicole Toepfner
- Center for Molecular and Cellular BioengineeringBiotechnology Center, Technische Universität Dresden Dresden Germany
- Department of PediatricsUniversity Clinic Carl Gustav Carus, Technische Universität Dresden Dresden Germany
| | | | - Nehal N Mehta
- National Heart Lung and Blood InstituteNational Institutes of Health Bethesda MD USA
| | - Mariana J Kaplan
- Systemic Autoimmunity BranchNational Institute of Arthritis and Musculoskeletal and Skin DiseasesNational Institutes of Health Bethesda Maryland USA
| | | | - Jochen Guck
- Max‐Planck‐Institut für die Physik des Lichts & Max‐Planck‐Zentrum für Physik und Medizin Erlangen Germany
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5
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Oropesa-Nuñez R, Keshavan S, Dante S, Diaspro A, Mannini B, Capitini C, Cecchi C, Stefani M, Chiti F, Canale C. Toxic HypF-N Oligomers Selectively Bind the Plasma Membrane to Impair Cell Adhesion Capability. Biophys J 2019; 114:1357-1367. [PMID: 29590593 DOI: 10.1016/j.bpj.2018.02.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Revised: 01/27/2018] [Accepted: 02/02/2018] [Indexed: 12/29/2022] Open
Abstract
The deposition of fibrillar protein aggregates in human organs is the hallmark of several pathological states, including highly debilitating neurodegenerative disorders and systemic amyloidoses. It is widely accepted that small oligomers arising as intermediates in the aggregation process, released by fibrils, or growing in secondary nucleation steps are the cytotoxic entities in protein-misfolding diseases, notably neurodegenerative conditions. Increasing evidence indicates that cytotoxicity is triggered by the interaction between nanosized protein aggregates and cell membranes, even though little information on the molecular details of such interaction is presently available. In this work, we propose what is, to our knowledge, a new approach, based on the use of single-cell force spectroscopy applied to multifunctional substrates, to study the interaction between protein oligomers, cell membranes, and/or the extracellular matrix. We compared the interaction of single Chinese hamster ovary cells with two types of oligomers (toxic and nontoxic) grown from the N-terminal domain of the Escherichia coli protein HypF. We were able to quantify the affinity between both oligomer type and the cell membrane by measuring the mechanical work needed to detach the cells from the aggregates, and we could discriminate the contributions of the membrane lipid and protein fractions to such affinity. The fundamental role of the ganglioside GM1 in the membrane-oligomers interaction was also highlighted. Finally, we observed that the binding of toxic oligomers to the cell membrane significantly affects the functionality of adhesion molecules such as Arg-Gly-Asp binding integrins, and that this effect requires the presence of the negatively charged sialic acid moiety of GM1.
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Affiliation(s)
- Reinier Oropesa-Nuñez
- Department of Nanophysics, Istituto Italiano di Tecnologia, Genova, Italy; DIBRIS Department, University of Genova, Genova, Italy
| | - Sandeep Keshavan
- Department of Nanophysics, Istituto Italiano di Tecnologia, Genova, Italy; DIBRIS Department, University of Genova, Genova, Italy
| | - Silvia Dante
- Department of Nanophysics, Istituto Italiano di Tecnologia, Genova, Italy
| | - Alberto Diaspro
- Department of Nanophysics, Istituto Italiano di Tecnologia, Genova, Italy; Department of Physics, University of Genova, Genova, Italy.
| | - Benedetta Mannini
- Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
| | - Claudia Capitini
- Section of Biochemistry, Department of Experimental and Clinical Biomedical Sciences, University of Florence, Firenze, Italy
| | - Cristina Cecchi
- Section of Biochemistry, Department of Experimental and Clinical Biomedical Sciences, University of Florence, Firenze, Italy
| | - Massimo Stefani
- Section of Biochemistry, Department of Experimental and Clinical Biomedical Sciences, University of Florence, Firenze, Italy
| | - Fabrizio Chiti
- Section of Biochemistry, Department of Experimental and Clinical Biomedical Sciences, University of Florence, Firenze, Italy
| | - Claudio Canale
- Department of Nanophysics, Istituto Italiano di Tecnologia, Genova, Italy; Department of Physics, University of Genova, Genova, Italy
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6
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Pleshakova TO, Bukharina NS, Archakov AI, Ivanov YD. Atomic Force Microscopy for Protein Detection and Their Physicoсhemical Characterization. Int J Mol Sci 2018; 19:E1142. [PMID: 29642632 PMCID: PMC5979402 DOI: 10.3390/ijms19041142] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Revised: 03/30/2018] [Accepted: 04/05/2018] [Indexed: 11/18/2022] Open
Abstract
This review is focused on the atomic force microscopy (AFM) capabilities to study the properties of protein biomolecules and to detect the proteins in solution. The possibilities of application of a wide range of measuring techniques and modes for visualization of proteins, determination of their stoichiometric characteristics and physicochemical properties, are analyzed. Particular attention is paid to the use of AFM as a molecular detector for detection of proteins in solutions at low concentrations, and also for determination of functional properties of single biomolecules, including the activity of individual molecules of enzymes. Prospects for the development of AFM in combination with other methods for studying biomacromolecules are discussed.
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Affiliation(s)
| | - Natalia S Bukharina
- Institute of Biomedical Chemistry, 10, Pogodinskaya St., 119121 Moscow, Russia.
| | | | - Yuri D Ivanov
- Institute of Biomedical Chemistry, 10, Pogodinskaya St., 119121 Moscow, Russia.
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7
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Tran DP, Takemura K, Kuwata K, Kitao A. Protein-Ligand Dissociation Simulated by Parallel Cascade Selection Molecular Dynamics. J Chem Theory Comput 2017; 14:404-417. [PMID: 29182324 DOI: 10.1021/acs.jctc.7b00504] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We investigated the dissociation process of tri-N-acetyl-d-glucosamine from hen egg white lysozyme using parallel cascade selection molecular dynamics (PaCS-MD), which comprises cycles of multiple unbiased MD simulations using a selection of MD snapshots as the initial structures for the next cycle. Dissociation was significantly accelerated by PaCS-MD, in which the probability of rare event occurrence toward dissociation was enhanced by the selection and rerandomization of the initial velocities. Although this complex was stable during 1 μs of conventional MD, PaCS-MD easily induced dissociation within 100-101 ns. We found that velocity rerandomization enhances the dissociation of triNAG from the bound state, whereas diffusion plays a more important role in the unbound state. We calculated the dissociation free energy by analyzing all PaCS-MD trajectories using the Markov state model (MSM), compared the results to those obtained by combinations of PaCS-MD and umbrella sampling (US), steered MD (SMD) and US, and SMD and the Jarzynski equality, and experimentally determined binding free energy. PaCS-MD/MSM yielded results most comparable to the experimentally determined binding free energy, independent of simulation parameter variations, and also gave the lowest standard errors.
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Affiliation(s)
- Duy Phuoc Tran
- Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo , 5-1-5 Kashiwanoha, Kashiwa-shi, Chiba 277-8562, Japan
| | - Kazuhiro Takemura
- Institute of Molecular and Cellular Biosciences, The University of Tokyo , 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan
| | - Kazuo Kuwata
- Center for Emerging Infectious Diseases, Gifu University , 1-1 Yanagido, Gifu-shi, Gifu 501-1194, Japan
| | - Akio Kitao
- School of Life Science and Technology, Tokyo Institute of Technology , 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550, Japan
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8
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QIN GG, LI WH, XU JC, KOU XL, ZHAO R, LUO F, FANG XH. Development of Integrated Atomic Force Microscopy and Fluorescence Microscopy for Single-Molecule Analysis in Living Cells. CHINESE JOURNAL OF ANALYTICAL CHEMISTRY 2017. [DOI: 10.1016/s1872-2040(17)61056-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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9
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In vitro model of bone to facilitate measurement of adhesion forces and super-resolution imaging of osteoclasts. Sci Rep 2016; 6:22585. [PMID: 26935172 PMCID: PMC4776281 DOI: 10.1038/srep22585] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Accepted: 02/18/2016] [Indexed: 11/08/2022] Open
Abstract
To elucidate processes in the osteoclastic bone resorption, visualise resorption and related actin reorganisation, a combination of imaging technologies and an applicable in vitro model is needed. Nanosized bone powder from matching species is deposited on any biocompatible surface in order to form a thin, translucent, smooth and elastic representation of injured bone. Osteoclasts cultured on the layer expressed matching morphology to ones cultured on sawed cortical bone slices. Resorption pits were easily identified by reflectance microscopy. The coating allowed actin structures on the bone interface to be visualised with super-resolution microscopy along with a detailed interlinked actin networks and actin branching in conjunction with V-ATPase, dynamin and Arp2/3 at actin patches. Furthermore, we measured the timescale of an adaptive osteoclast adhesion to bone by force spectroscopy experiments on live osteoclasts with bone-coated AFM cantilevers. Utilising the in vitro model and the advanced imaging technologies we localised immunofluorescence signals in respect to bone with high precision and detected resorption at its early stages. Put together, our data supports a cyclic model for resorption in human osteoclasts.
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10
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Evaluation of Cell Membrane-Modulating Properties of Non-Ionic Surfactants with the use of Atomic Force Spectroscopy. BIONANOSCIENCE 2015. [DOI: 10.1007/s12668-015-0166-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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11
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Codan B, Del Favero G, Martinelli V, Long CS, Mestroni L, Sbaizero O. Exploring the elasticity and adhesion behavior of cardiac fibroblasts by atomic force microscopy indentation. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2014; 40:427-34. [PMID: 24857511 DOI: 10.1016/j.msec.2014.04.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2013] [Revised: 02/28/2014] [Accepted: 04/02/2014] [Indexed: 12/19/2022]
Abstract
AFM was used to collect the whole force-deformation cell curves. They provide both the elasticity and adhesion behavior of mouse primary cardiac fibroblasts. To confirm the hypothesis that a link exists between the membrane receptors and the cytoskeletal filaments causing therefore changing in both elasticity and adhesion behavior, actin-destabilizing Cytochalsin D was administrated to the fibroblasts. From immunofluorescence observation and AFM loading/unloading curves, cytoskeletal reorganization as well as a change in the elasticity and adhesion was indeed observed. Elasticity of control fibroblasts is three times higher than that for fibroblasts treated with 0.5 μM Cytochalasin. Moreover, AFM loading-unloading curves clearly show the different mechanical behavior of the two different cells analyzed: (i) for control cells the AFM cantilever rises during the dwell time while cells with Cytochalasin fail to show such an active resistance; (ii) the maximum force to deform control cells is quite higher and as far as adhesion is concern (iii) the maximum separation force, detachment area and the detachment process time are much larger for control compared to the Cytochalasin treated cells. Therefore, alterations in the cytoskeleton suggest that a link must exist between the membrane receptors and the cytoskeletal filaments beneath the cellular surface and inhibition of actin polymerization has effects on the whole cell mechanical behavior as well as adhesion.
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Affiliation(s)
- B Codan
- Department of Engineering and Architecture, University of Trieste, Italy
| | - G Del Favero
- Department of Engineering and Architecture, University of Trieste, Italy
| | - V Martinelli
- Department of Engineering and Architecture, University of Trieste, Italy; International Center for Genetic Engineering and Biotechnology, Trieste, Italy
| | - C S Long
- University of Colorado Cardiovascular Institute, University of Colorado Denver, Aurora, CO, USA
| | - L Mestroni
- University of Colorado Cardiovascular Institute, University of Colorado Denver, Aurora, CO, USA
| | - O Sbaizero
- Department of Engineering and Architecture, University of Trieste, Italy.
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12
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Li S, Shi R, Wang Q, Cai J, Zhang S. Nanostructure and β1-integrin distribution analysis of pig's spermatogonial stem cell by atomic force microscopy. Gene 2012; 495:189-93. [PMID: 22237019 DOI: 10.1016/j.gene.2011.12.044] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2011] [Accepted: 12/22/2011] [Indexed: 01/15/2023]
Abstract
Spermatogonial stem cells (SSCs) provide the foundation for spermatogenesis and male fertility. However, spermatogenesis has direct links with some adhesion molecules on SSCs membrane. Β1-integrin (CD29) is such a kind of adhesion molecule and a biomarker of pig's SSCs. Therefore, quantitative characteristics of β1-integrin expression level in a single cell could help us to capture the signal switch and understand the mechanism of spermatogenesis. In this study, atomic force microscopy (AFM) was used to obtain the morphology and ultrastructure of SSCs at nanometer level, and the CD29 Ab-functionalized AFM tip was used to examine β1-integrin distribution on the cell membrane. There were many force-binding spots on about 50% of cell membrane binding to the CD29 Ab-functionalized AFM tip, and the mean bind rupture force was 283.63±12.56PN which was much larger than the non-specific average force 70.75±10.95PN. Meanwhile, β1-integrin on SSCs membrane was distributed non-uniformly, and there were some β1-integrins appeared to be expressed as 150-350 nm nanoclusters on the membrane. Our results discovered the structure of SSCs at nanometer level by AFM. The force between β1-integrin antigen-antibody interactions and the distribution of β1-integrin protein on SSCs membrane were also firstly demonstrated.
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Affiliation(s)
- Shengpu Li
- Department of Chemistry, Jinan University, Guangzhou 510632, People's Republic of China
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13
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Mayyas E, Bernardo M, Runyan L, Sohail A, Subba-Rao V, Pantea M, Fridman R, Hoffmann PM. Dissociation Kinetics of an Enzyme−Inhibitor System Using Single-Molecule Force Measurements. Biomacromolecules 2010; 11:3352-8. [DOI: 10.1021/bm100844x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Essa Mayyas
- Department of Physics and Astronomy, and Department of Pathology and Karmanos Cancer Institute, Wayne State University, Detroit, Michigan 48201, United States
| | - Margarida Bernardo
- Department of Physics and Astronomy, and Department of Pathology and Karmanos Cancer Institute, Wayne State University, Detroit, Michigan 48201, United States
| | - Lindsay Runyan
- Department of Physics and Astronomy, and Department of Pathology and Karmanos Cancer Institute, Wayne State University, Detroit, Michigan 48201, United States
| | - Anjum Sohail
- Department of Physics and Astronomy, and Department of Pathology and Karmanos Cancer Institute, Wayne State University, Detroit, Michigan 48201, United States
| | - Venkatesh Subba-Rao
- Department of Physics and Astronomy, and Department of Pathology and Karmanos Cancer Institute, Wayne State University, Detroit, Michigan 48201, United States
| | - Mircea Pantea
- Department of Physics and Astronomy, and Department of Pathology and Karmanos Cancer Institute, Wayne State University, Detroit, Michigan 48201, United States
| | - Rafael Fridman
- Department of Physics and Astronomy, and Department of Pathology and Karmanos Cancer Institute, Wayne State University, Detroit, Michigan 48201, United States
| | - Peter M. Hoffmann
- Department of Physics and Astronomy, and Department of Pathology and Karmanos Cancer Institute, Wayne State University, Detroit, Michigan 48201, United States
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14
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Lal R, Ramachandran S, Arnsdorf MF. Multidimensional atomic force microscopy: a versatile novel technology for nanopharmacology research. AAPS JOURNAL 2010; 12:716-28. [PMID: 20957528 PMCID: PMC2976997 DOI: 10.1208/s12248-010-9232-y] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/25/2010] [Accepted: 09/14/2010] [Indexed: 11/30/2022]
Abstract
Nanotechnology is giving us a glimpse into a nascent field of nanopharmacology that deals with pharmacological phenomena at molecular scale. This review presents our perspective on the use of scanning probe microscopy techniques with special emphasis to multidimensional atomic force microscopy (m-AFM) to explore this new field with a particular emphasis to define targets, design therapeutics, and track outcomes of molecular-scale pharmacological interactions. The approach will be to first discuss operating principles of m-AFM and provide representative examples of studies to understand human health and disease at the molecular level and then to address different strategies in defining target macromolecules, screening potential drug candidates, developing and characterizing of drug delivery systems, and monitoring target–drug interactions. Finally, we will discuss some future directions including AFM tip-based parallel sensors integrated with other high-throughput technologies which could be a powerful platform for drug discovery.
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Affiliation(s)
- Ratnesh Lal
- Department of Bioengineering, University of California, San Diego, La Jolla, 92093-0412, USA.
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15
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Friedrichs J, Helenius J, Muller DJ. Quantifying cellular adhesion to extracellular matrix components by single-cell force spectroscopy. Nat Protoc 2010. [DOI: 10.1038/nprot.2010.89%0aatomic] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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16
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Friedrichs J, Helenius J, Muller DJ. Quantifying cellular adhesion to extracellular matrix components by single-cell force spectroscopy. Nat Protoc 2010; 5:1353-61. [PMID: 20595963 DOI: 10.1038/nprot.2010.89] [Citation(s) in RCA: 129] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Atomic force microscopy (AFM)-based single-cell force spectroscopy (SCFS) enables the quantitative study of cell adhesion under physiological conditions. SCFS probes adhesive interactions of single living cells with substrates such as extracellular matrix (ECM) proteins and other cells. Here we present a protocol to study integrin-mediated adhesion of HeLa cells to collagen type I using SCFS. We describe procedures for (i) functionalization of AFM cantilevers with the lectin concanavalin A and supports with collagen, (ii) cell handling and attachment to the AFM cantilever, (iii) measurement of adhesion forces and (iv) data analysis and interpretation. Although designed to measure HeLa cell adhesion to collagen, the protocol can be modified for other cell lines and ECM proteins. Compared with other SCFS assays (for example, optical tweezer, biomembrane force probe), AFM-based SCFS has a more versatile force detection range, and it can therefore be used to address a broader range of biological questions. The protocol can be completed in 2-3 d.
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Affiliation(s)
- Jens Friedrichs
- Department of Biosystems Science and Engineering, ETH Zürich, Basel, Switzerland
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17
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Multidimensional atomic force microscopy for drug discovery: A versatile tool for defining targets, designing therapeutics and monitoring their efficacy. Life Sci 2010; 86:545-62. [DOI: 10.1016/j.lfs.2009.02.030] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2009] [Accepted: 02/13/2009] [Indexed: 11/30/2022]
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18
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Soumetz FC, Saenz JF, Pastorino L, Ruggiero C, Nosi D, Raiteri R. Investigation of integrin expression on the surface of osteoblast-like cells by atomic force microscopy. Ultramicroscopy 2010; 110:330-8. [PMID: 20149538 DOI: 10.1016/j.ultramic.2010.01.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2009] [Revised: 11/27/2009] [Accepted: 01/12/2010] [Indexed: 11/25/2022]
Abstract
The transforming growth factor beta1 (TGF-beta1) is a human cytokine which has been demonstrated to modulate cell surface integrin repertoire. In this work integrin expression in response to TGF-beta1 stimulation has been investigated on the surface of human osteoblast-like cells. We used atomic force microscopy (AFM) and confocal laser scanning microscopy to assess integrin expression and to evaluate their distribution over the dorsal side of the plasma membrane. AFM probes have been covalently functionalized with monoclonal antibodies specific to the beta1 integrin subunit. Force curves have been collected in order to obtain maps of the interaction between the immobilized antibody and the respective cell membrane receptors. Adhesion peaks have been automatically detected by means of an ad hoc developed data analysis software. The specificity of the detected interactions has been assessed by adding free antibody in the solution and monitoring the dramatic decrease in the recorded interactions. In addition, the effect of TGF-beta1 treatment on both the fluorescence signal and the adhesion events has been tested. The level of expression of the beta1 integrin subunit was enhanced by TGF-beta1. As a further analysis, the adhesion force of the single living cells to the substrate was measured by laterally pushing the cell with the AFM tip and measuring the force necessary to displace it. The treatment with TGF-beta1 resulted in a decrease of the cell/substrate adhesion force. Results obtained by AFM have been validated by confocal laser scanning microscopy thus demonstrating the high potential of the AFM technique for the investigation of cell surface receptors distribution and trafficking at the nanoscale.
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Affiliation(s)
- Federico Caneva Soumetz
- Department of Communication, Computer and System Sciences, University of Genova, Via Opera Pia, 13-16145 Genova, Italy
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19
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Cheung JWC, Walker GC. Immuno-atomic force microscopy characterization of adsorbed fibronectin. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2008; 24:13842-9. [PMID: 19360949 DOI: 10.1021/la802452v] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
The fibronectin (Fn) binding conformation on mica and ultraflat poly(D,L-lactide-co-glycolide) (UPLGA) was characterized using atomic force microscopy (AFM). AFM topographic images showed that Fn was in an extended form on mica and in a compact structure on UPLGA. With immuno-AFM, an antibody (Ab(hep)) was used to characterize the Fn binding conformation. When Fn opens its binding site for an antibody upon adsorption to a surface, the resulting Fn-antibody complex creates an additional peak in the sample's height distribution. Immuno-AFM uses this change to detect antigen-antibody binding. In this letter, height histograms (distributions) were generated using the mean true height of molecules, which was measured by examining the histogram for each individual molecule and subtracting the mica background. Mean true height values were obtained from the histograms and showed that Fn and Ab(hep) formed complexes on mica, signifying that one of the heparin binding sites on Fn was open when Fn was adsorbed to mica. The mean true height of the Fn-antibody complex from the histogram is greater than expected, suggesting that the antibody had pulled the extended "arms" of Fn together and caused an Fn conformation change upon binding. The height histograms can illustrate the Fn binding conformation and other antigen-antibody binding.
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Affiliation(s)
- Jane W C Cheung
- Department of Chemistry, University of Toronto, Toronto, Ontario, Canada M5S 3H6.
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20
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Qiu D, Xiang J, Li Z, Krishnamoorthy A, Chen L, Wang R. Profiling TRA-1-81 antigen distribution on a human embryonic stem cell. Biochem Biophys Res Commun 2008; 369:735-40. [PMID: 18313397 DOI: 10.1016/j.bbrc.2008.02.102] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2008] [Accepted: 02/20/2008] [Indexed: 10/22/2022]
Abstract
Human embryonic stem (hES) cells hold great promise in regenerative medicine. Although hES cells have unlimited self-renewal potential, they tend to differentiate spontaneously in culture. TRA-1-81 is a biomarker of undifferentiated hES cells. Quantitative characterization of TRA-1-81 expression level in a single cell helps capture the "turn-on" signal and understand the mechanism of early differentiation. Here, we report on our examination of TRA-1-81 distribution and association on a hES cell membrane using an atomic force microscope (AFM). Our results suggest that aggregated distribution of TRA-1-81 antigen is characteristic for undifferentiated hES cells. We also evaluated the TRA-1-81 expression level at approximately 17,800 epitopes and approximately 700 epitopes per cell on an undifferentiated cell and a spontaneously differentiated cell, respectively. The method in this study can be adapted in examining other surface proteins on various cell types, thus providing a general tool for investigating protein distribution and association at the single cell level.
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Affiliation(s)
- Dengli Qiu
- Department of Biological, Chemical and Physical Sciences, Illinois Institute of Technology, 3101 S. Dearborn Street, Life Sciences Building, Chicago, IL 60616, USA
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21
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AFM as a tool to probe and manipulate cellular processes. Pflugers Arch 2007; 456:61-70. [DOI: 10.1007/s00424-007-0414-0] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2007] [Revised: 11/23/2007] [Accepted: 11/27/2007] [Indexed: 10/22/2022]
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22
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An historical perspective on cell mechanics. Pflugers Arch 2007; 456:3-12. [DOI: 10.1007/s00424-007-0405-1] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2007] [Revised: 11/12/2007] [Accepted: 11/15/2007] [Indexed: 11/26/2022]
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23
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Yersin A, Steiner P. Receptor trafficking and AFM. Pflugers Arch 2007; 456:189-98. [DOI: 10.1007/s00424-007-0380-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2007] [Accepted: 10/26/2007] [Indexed: 12/27/2022]
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24
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Lee S, Mandic J, Van Vliet KJ. Chemomechanical mapping of ligand-receptor binding kinetics on cells. Proc Natl Acad Sci U S A 2007; 104:9609-14. [PMID: 17535923 PMCID: PMC1887608 DOI: 10.1073/pnas.0702668104] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The binding kinetics between cell surface receptors and extracellular biomolecules is critical to all intracellular and intercellular activity. Modeling and prediction of receptor-mediated cell functions are facilitated by measurement of the binding properties on whole cells, ideally indicating the subcellular locations or cytoskeletal associations that may affect the function of bound receptors. This dual need is particularly acute vis à vis ligand engineering and clinical applications of antibodies to neutralize pathological processes. Here, we map individual receptors and determine whole-cell binding kinetics by means of functionalized force imaging, enabled by scanning probe microscopy and molecular force spectroscopy of intact cells with biomolecule-conjugated mechanical probes. We quantify the number, distribution, and association/dissociation rate constants of vascular endothelial growth factor receptor-2 with respect to a monoclonal antibody on both living and fixed human microvascular endothelial cells. This general approach to direct receptor imaging simultaneously quantifies both the binding kinetics and the nonuniform distribution of these receptors with respect to the underlying cytoskeleton, providing spatiotemporal visualization of cell surface dynamics that regulate receptor-mediated behavior.
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Affiliation(s)
- Sunyoung Lee
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139
| | - Jelena Mandic
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139
| | - Krystyn J. Van Vliet
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139
- *To whom correspondence should be addressed at:
Massachusetts Institute of Technology, Room 8-237, 77 Massachusetts Avenue, Cambridge, MA 02139. E-mail:
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25
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Forman JR, Clarke J. Mechanical unfolding of proteins: insights into biology, structure and folding. Curr Opin Struct Biol 2007; 17:58-66. [PMID: 17251000 DOI: 10.1016/j.sbi.2007.01.006] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2006] [Revised: 12/13/2006] [Accepted: 01/12/2007] [Indexed: 10/23/2022]
Abstract
Since user-friendly atomic force microscopes came onto the market a few years ago, scientists have explored the response of many proteins to applied force. This field has now matured beyond the phenomenological with exciting recent developments, particularly with regards to research into biological questions. For example, detailed mechanistic studies have suggested how mechanically active proteins perform their functions. Also, in vitro forced unfolding has been compared with in vivo protein import and degradation. Additionally, investigations have been carried out that probe the relationship between protein structure and response to applied force, an area that has benefited significantly from synergy between experiments and simulations. Finally, recent technological developments offer exciting new avenues for experimental studies.
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Affiliation(s)
- Julia R Forman
- Cambridge University Department of Chemistry, MRC Centre for Protein Engineering, Lensfield Road, Cambridge CB2 1EW, UK
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26
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Zhou J, Zhang L, Leng Y, Tsao HK, Sheng YJ, Jiang S. Unbinding of the streptavidin-biotin complex by atomic force microscopy: A hybrid simulation study. J Chem Phys 2006; 125:104905. [PMID: 16999548 DOI: 10.1063/1.2337629] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
A hybrid molecular simulation technique, which combines molecular dynamics and continuum mechanics, was used to study the single-molecule unbinding force of a streptavidin-biotin complex. The hybrid method enables atomistic simulations of unbinding events at the millisecond time scale of atomic force microscopy (AFM) experiments. The logarithmic relationship between the unbinding force of the streptavidin-biotin complex and the loading rate (the product of cantilever spring constant and pulling velocity) in AFM experiments was confirmed by hybrid simulations. The unbinding forces, cantilever and tip positions, locations of energy barriers, and unbinding pathway were analyzed. Hybrid simulation results from this work not only interpret unbinding AFM experiments but also provide detailed molecular information not available in AFM experiments.
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Affiliation(s)
- Jian Zhou
- Department of Chemical Engineering, University of Washington, Seattle, WA 98195, USA
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27
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Abstract
Gap junctional hemichannels mediate cell-extracellular communication. A hemichannel is made of six connexin (Cx) subunits; each connexin has four transmembrane domains, two extracellular loops, and cytoplasmic amino- and carboxyl-terminals (CTs). The extracellular domains are arranged differently at non-junctional and junctional (gap junction) regions, although very little is known about their flexibility and conformational energetics. The cytoplasmic tail differs considerably in the size and amino acid sequence for different connexins and is predicted to be involved in the channel open and closed conformations. For large connexins, such as Cx43, the CT makes large cytoplasmic fuzz visible under electron microscopy. If this CT domain controls channel permeability by physical occlusion of the pore mouth, movement of this portion could open or close the channel. We used atomic force microscopy-based single molecule spectroscopy with antibody-modified atomic force microscopy tips and connexin mimetic peptide modified tips to examine the flexibility of extracellular loop and CT domains and to estimate the energetics of their movements. Antibody to the CT portion closer to the membrane stretches the tail to a shorter length, and the antibody to CT tail stretches the tail to a longer length. The stretch length and the energy required for stretching the various portions of the carboxyl tail support the ball and chain model for hemichannel conformational changes.
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Affiliation(s)
- Fei Liu
- Neuroscience Research Institute, University of California, Santa Barbara, California 93106, USA
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28
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Kirkham J, Andreev I, Robinson C, Brookes SJ, Shore RC, Smith DA. Evidence for direct amelogenin-target cell interactions using dynamic force spectroscopy. Eur J Oral Sci 2006; 114 Suppl 1:219-24; discussion 254-6, 381-2. [PMID: 16674689 DOI: 10.1111/j.1600-0722.2006.00290.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Increasing evidence suggests that amelogenin, long held to be a structural protein of developing enamel matrix, may also have cell signaling functions. However, a mechanism for amelogenin cell signaling has yet to be described. The aim of the present study was to use dynamic chemical force spectroscopy to measure amelogenin interactions with possible target cells. Full-length amelogenin (rM179) was covalently attached to silicon nitride AFM tips. Synthetic RGD peptides and unmodified AFM tips were used as controls. Amelogenin-RGD cell binding force measurements were carried out using human periodontal ligament fibroblasts (HPDF) from primary explants and a commercially available osteoblast-like human sarcoma cell line as the targets. Results indicated a linear logarithmic dependence between loading rate and unbinding force for amelogenin-RGD target cells across the range of loading rates used. For RGD controls, binding events measured at 5.5 nN s-1 force loading rate resulted in a mean force of 60 pN. Values for amelogenin-fibroblast and amelogenin-osteoblast-like cell unbinding forces, measured at similar loading rates, were 50 and 55 pN, respectively. These data suggest that amelogenin interacts with potential target cells with forces characteristic of specific ligand-receptor binding, suggesting a direct effect for amelogenin at target cell membranes.
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Affiliation(s)
- Jennifer Kirkham
- Department of Oral Biology, Leeds Dental Institute, University of Leeds, Leeds, UK.
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29
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Probing molecular interaction between transferrin and anti-transferrin by atomic force microscope. ACTA ACUST UNITED AC 2006. [DOI: 10.1007/s11434-006-0405-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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30
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Reddy CVG, Malinowska K, Menhart N, Wang R. Identification of TrkA on living PC12 cells by atomic force microscopy. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2004; 1667:15-25. [PMID: 15533302 DOI: 10.1016/j.bbamem.2004.08.011] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2003] [Revised: 08/17/2004] [Accepted: 08/26/2004] [Indexed: 11/17/2022]
Abstract
In neural cells, nerve growth factor (NGF) initiates its survival signal through the binding to its cell surface receptor tyrosine kinase A (TrkA). Understanding the pattern of TrkA distribution and association in living cells can provide a fingerprint for the diagnostic comparison with alterations underlying ligand-receptor dysfunction seen in various neurological diseases. In this study, we use the NGF-TrkA-specific interaction as a probe to identify TrkA on living PC12 cell by atomic force microscopy (AFM). An NGF-modified AFM tip was used to perform force volume (FV) imaging, generating a 2D force map to illustrate the distribution and association of TrkA on PC12 cell membrane. It is found that TrkA is highly aggregated at local regions of the cell. This unique protein association may be required to promote its function as a receptor of NGF. The methodology that we developed in this study can be adapted by other systems, thus providing a general tool for investigating protein association in its natural environment.
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Affiliation(s)
- C V Gopal Reddy
- Department of Biological, Chemical and Physical Sciences, Illinois Institute of Technology, Chicago, IL 60616, USA
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31
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Almqvist N, Bhatia R, Primbs G, Desai N, Banerjee S, Lal R. Elasticity and adhesion force mapping reveals real-time clustering of growth factor receptors and associated changes in local cellular rheological properties. Biophys J 2004; 86:1753-62. [PMID: 14990502 PMCID: PMC1304010 DOI: 10.1016/s0006-3495(04)74243-5] [Citation(s) in RCA: 127] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Cell surface macromolecules such as receptors and ion channels serve as the interface link between the cytoplasm and the extracellular region. Their density, distribution, and clustering are key spatial features influencing effective and proper physical and biochemical cellular responses to many regulatory signals. In this study, the effect of plasma-membrane receptor clustering on local cell mechanics was obtained from maps of interaction forces between antibody-conjugated atomic force microscope tips and a specific receptor, a vascular endothelial growth factor (VEGF) receptor. The technique allows simultaneous measurement of the real-time motion of specific macromolecules and their effect on local rheological properties like elasticity. The clustering was stimulated by online additions of VEGF, or antibody against VEGF receptors. VEGF receptors are found to concentrate toward the cell boundaries and cluster rapidly after the online additions commence. Elasticity of regions under the clusters is found to change remarkably, with order-of-magnitude stiffness reductions and fluidity increases. The local stiffness reductions are nearly proportional to receptor density and, being concentrated near the cell edges, provide a mechanism for cell growth and angiogenesis.
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Affiliation(s)
- N Almqvist
- Department of Applied Physics & Mechanical Engineering, Luleå University of Technology, Luleå, Sweden
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32
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Dufrêne YF. Recent progress in the application of atomic force microscopy imaging and force spectroscopy to microbiology. Curr Opin Microbiol 2003; 6:317-23. [PMID: 12831910 DOI: 10.1016/s1369-5274(03)00058-4] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Atomic force microscopy imaging and force spectroscopy have recently opened a range of novel applications in microbiology. During the past two years, rapid advances have been made using atomic force microscopy to visualize the surface structure of two-dimensional bacterial protein crystals, biofilms and individual cells in physiological conditions. There has also been remarkable progress in using force spectroscopy to measure biomolecular interactions and physical properties of microbial surfaces. Specific highlights include the imaging and manipulation of membrane proteins at the subnanometer level, the observation of the surface of living cells at high resolution, the mapping of local properties such as surface charges, the measurement of elastic properties of cell-surface constituents and the probing of cellular interactions using functionalized probes.
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Affiliation(s)
- Yves F Dufrêne
- Unité de chimie des interfaces, Université catholique de Louvain, Croix du Sud 2/18, B-1348 Louvain-la-Neuve, Belgium.
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