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Ringer P, Colo G, Fässler R, Grashoff C. Sensing the mechano-chemical properties of the extracellular matrix. Matrix Biol 2017; 64:6-16. [DOI: 10.1016/j.matbio.2017.03.004] [Citation(s) in RCA: 75] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2017] [Revised: 03/29/2017] [Accepted: 03/30/2017] [Indexed: 12/13/2022]
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52
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Toplak T, Palmieri B, Juanes-García A, Vicente-Manzanares M, Grant M, Wiseman PW. Wavelet Imaging on Multiple Scales (WIMS) reveals focal adhesion distributions, dynamics and coupling between actomyosin bundle stability. PLoS One 2017; 12:e0186058. [PMID: 29049414 PMCID: PMC5648137 DOI: 10.1371/journal.pone.0186058] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Accepted: 09/25/2017] [Indexed: 11/22/2022] Open
Abstract
We introduce and use Wavelet Imaging on Multiple Scales (WIMS) as an improvement to fluorescence correlation spectroscopy to measure physical processes and features that occur across multiple length scales. In this study, wavelet transforms of cell images are used to characterize molecular dynamics at the cellular and subcellular levels (i.e. focal adhesions). We show the usefulness of the technique by applying WIMS to an image time series of a migrating osteosarcoma cell expressing fluorescently labelled adhesion proteins, which allows us to characterize different components of the cell ranging from optical resolution scale through to focal adhesion and whole cell size scales. Using WIMS we measured focal adhesion numbers, orientation and cell boundary velocities for retraction and protrusion. We also determine the internal dynamics of individual focal adhesions undergoing assembly, disassembly or elongation. Thus confirming as previously shown, WIMS reveals that the number of adhesions and the area of the protruding region of the cell are strongly correlated, establishing a correlation between protrusion size and adhesion dynamics. We also apply this technique to characterize the behavior of adhesions, actin and myosin in Chinese hamster ovary cells expressing a mutant form of myosin IIB (1935D) that displays decreased filament stability and impairs front-back cell polarity. We find separate populations of actin and myosin at each adhesion pole for both the mutant and wild type form. However, we find these populations move rapidly inwards toward one another in the mutant case in contrast to the cells that express wild type myosin IIB where those populations remain stationary. Results obtained with these two systems demonstrate how WIMS has the potential to reveal novel correlations between chosen parameters that belong to different scales.
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Affiliation(s)
- Tim Toplak
- Department of Physics, McGill University, Montréal, Québec, Canada
| | - Benoit Palmieri
- Department of Physics, McGill University, Montréal, Québec, Canada
| | - Alba Juanes-García
- Universidad Autonoma de Madrid School of Medicine/IIS-Princesa Diego de Leon, Madrid, Spain
| | | | - Martin Grant
- Department of Physics, McGill University, Montréal, Québec, Canada
| | - Paul W. Wiseman
- Department of Physics, McGill University, Montréal, Québec, Canada
- Department of Chemistry, McGill University, Montréal, Québec, Canada
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53
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Nanoscale mechanobiology of cell adhesions. Semin Cell Dev Biol 2017; 71:53-67. [PMID: 28754443 DOI: 10.1016/j.semcdb.2017.07.029] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Revised: 07/17/2017] [Accepted: 07/19/2017] [Indexed: 12/16/2022]
Abstract
Proper physiological functions of cells and tissues depend upon their abilities to sense, transduce, integrate, and generate mechanical and biochemical signals. Although such mechanobiological phenomena are widely observed, the molecular mechanisms driving these outcomes are still not fully understood. Cell adhesions formed by integrins and cadherins receptors are key structures that process diverse sources of signals to elicit complex mechanobiological responses. Since the nanoscale is the length scale at which molecules interact to relay force and information, the understanding of cell adhesions at the nanoscale level is important for grasping the inner logics of cellular decision making. Until recently, the study of the biological nanoscale has been restricted by available molecular and imaging tools. Fortunately, rapid technological advances have increasingly opened up the nanoscale realm to systematic investigations. In this review, we discuss current insights and key open questions regarding the nanoscale structure and function relationship of cell adhesions, focusing on recent progresses in characterizing their composition, spatial organization, and cytomechanical operation.
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54
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Abstract
Talin has emerged as the key cytoplasmic protein that mediates integrin adhesion to the extracellular matrix. In this Review, we draw on experiments performed in mammalian cells in culture and Drosophila to present evidence that talin is the most important component of integrin adhesion complexes. We describe how the properties of this adaptor protein enable it to orchestrate integrin adhesions. Talin forms the core of integrin adhesion complexes by linking integrins directly to actin, increasing the affinity of integrin for ligands (integrin activation) and recruiting numerous proteins. It regulates the strength of integrin adhesion, senses matrix rigidity, increases focal adhesion size in response to force and serves as a platform for the building of the adhesion structure. Finally, the mechano-sensitive structure of talin provides a paradigm for how proteins transduce mechanical signals to chemical signals.
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Affiliation(s)
- Benjamin Klapholz
- Dept of Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge CB2 3DY, UK
| | - Nicholas H Brown
- Dept of Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge CB2 3DY, UK
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55
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Cardoso Dos Santos M, Déturche R, Vézy C, Jaffiol R. Topography of Cells Revealed by Variable-Angle Total Internal Reflection Fluorescence Microscopy. Biophys J 2017; 111:1316-1327. [PMID: 27653490 DOI: 10.1016/j.bpj.2016.06.043] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2016] [Revised: 05/24/2016] [Accepted: 06/28/2016] [Indexed: 11/17/2022] Open
Abstract
We propose an improved version of variable-angle total internal reflection fluorescence microscopy (vaTIRFM) adapted to modern TIRF setup. This technique involves the recording of a stack of TIRF images, by gradually increasing the incident angle of the light beam on the sample. A comprehensive theory was developed to extract the membrane/substrate separation distance from fluorescently labeled cell membranes. A straightforward image processing was then established to compute the topography of cells with a nanometric axial resolution, typically 10-20 nm. To highlight the new opportunities offered by vaTIRFM to quantify adhesion process of motile cells, adhesion of MDA-MB-231 cancer cells on glass substrate coated with fibronectin was examined.
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Affiliation(s)
- Marcelina Cardoso Dos Santos
- Laboratoire de Nanotechnologie et d'Instrumentation Optique, Institut Charles Delaunay - UMR 6281 Centre National de la Recherche Scientifique, Université de Technologie de Troyes, Troyes, France
| | - Régis Déturche
- Laboratoire de Nanotechnologie et d'Instrumentation Optique, Institut Charles Delaunay - UMR 6281 Centre National de la Recherche Scientifique, Université de Technologie de Troyes, Troyes, France
| | - Cyrille Vézy
- Laboratoire de Nanotechnologie et d'Instrumentation Optique, Institut Charles Delaunay - UMR 6281 Centre National de la Recherche Scientifique, Université de Technologie de Troyes, Troyes, France
| | - Rodolphe Jaffiol
- Laboratoire de Nanotechnologie et d'Instrumentation Optique, Institut Charles Delaunay - UMR 6281 Centre National de la Recherche Scientifique, Université de Technologie de Troyes, Troyes, France.
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56
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Mekhdjian AH, Kai F, Rubashkin MG, Prahl LS, Przybyla LM, McGregor AL, Bell ES, Barnes JM, DuFort CC, Ou G, Chang AC, Cassereau L, Tan SJ, Pickup MW, Lakins JN, Ye X, Davidson MW, Lammerding J, Odde DJ, Dunn AR, Weaver VM. Integrin-mediated traction force enhances paxillin molecular associations and adhesion dynamics that increase the invasiveness of tumor cells into a three-dimensional extracellular matrix. Mol Biol Cell 2017; 28:1467-1488. [PMID: 28381423 PMCID: PMC5449147 DOI: 10.1091/mbc.e16-09-0654] [Citation(s) in RCA: 83] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2016] [Revised: 03/24/2017] [Accepted: 03/29/2017] [Indexed: 12/21/2022] Open
Abstract
Mammary tumor cells adopt a basal-like phenotype when invading through a dense, stiffened, 3D matrix. These cells exert higher integrin-mediated traction forces, consistent with a physical motor-clutch model, display an altered molecular organization at the nanoscale, and recruit a suite of paxillin-associated proteins implicated in metastasis. Metastasis requires tumor cells to navigate through a stiff stroma and squeeze through confined microenvironments. Whether tumors exploit unique biophysical properties to metastasize remains unclear. Data show that invading mammary tumor cells, when cultured in a stiffened three-dimensional extracellular matrix that recapitulates the primary tumor stroma, adopt a basal-like phenotype. Metastatic tumor cells and basal-like tumor cells exert higher integrin-mediated traction forces at the bulk and molecular levels, consistent with a motor-clutch model in which motors and clutches are both increased. Basal-like nonmalignant mammary epithelial cells also display an altered integrin adhesion molecular organization at the nanoscale and recruit a suite of paxillin-associated proteins implicated in invasion and metastasis. Phosphorylation of paxillin by Src family kinases, which regulates adhesion turnover, is similarly enhanced in the metastatic and basal-like tumor cells, fostered by a stiff matrix, and critical for tumor cell invasion in our assays. Bioinformatics reveals an unappreciated relationship between Src kinases, paxillin, and survival of breast cancer patients. Thus adoption of the basal-like adhesion phenotype may favor the recruitment of molecules that facilitate tumor metastasis to integrin-based adhesions. Analysis of the physical properties of tumor cells and integrin adhesion composition in biopsies may be predictive of patient outcome.
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Affiliation(s)
- Armen H Mekhdjian
- Department of Chemical Engineering, Stanford University, Stanford, CA 94305
| | - FuiBoon Kai
- Center for Bioengineering and Tissue Regeneration, Department of Surgery, University of California, San Francisco, San Francisco, CA 94143
| | - Matthew G Rubashkin
- Center for Bioengineering and Tissue Regeneration, Department of Surgery, University of California, San Francisco, San Francisco, CA 94143
| | - Louis S Prahl
- Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN 55455
| | - Laralynne M Przybyla
- Center for Bioengineering and Tissue Regeneration, Department of Surgery, University of California, San Francisco, San Francisco, CA 94143
| | - Alexandra L McGregor
- Nancy E. and Peter C. Meinig School of Biomedical Engineering and Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853
| | - Emily S Bell
- Nancy E. and Peter C. Meinig School of Biomedical Engineering and Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853
| | - J Matthew Barnes
- Center for Bioengineering and Tissue Regeneration, Department of Surgery, University of California, San Francisco, San Francisco, CA 94143
| | - Christopher C DuFort
- Center for Bioengineering and Tissue Regeneration, Department of Surgery, University of California, San Francisco, San Francisco, CA 94143
| | - Guanqing Ou
- Center for Bioengineering and Tissue Regeneration, Department of Surgery, University of California, San Francisco, San Francisco, CA 94143
| | - Alice C Chang
- Department of Chemical Engineering, Stanford University, Stanford, CA 94305
| | - Luke Cassereau
- Center for Bioengineering and Tissue Regeneration, Department of Surgery, University of California, San Francisco, San Francisco, CA 94143
| | - Steven J Tan
- Department of Chemical Engineering, Stanford University, Stanford, CA 94305
| | - Michael W Pickup
- Center for Bioengineering and Tissue Regeneration, Department of Surgery, University of California, San Francisco, San Francisco, CA 94143
| | - Jonathan N Lakins
- Center for Bioengineering and Tissue Regeneration, Department of Surgery, University of California, San Francisco, San Francisco, CA 94143
| | - Xin Ye
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142
| | - Michael W Davidson
- National High Magnetic Field Laboratory and Department of Biological Science, Florida State University, Tallahassee, FL 32306
| | - Jan Lammerding
- Nancy E. and Peter C. Meinig School of Biomedical Engineering and Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853
| | - David J Odde
- Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN 55455
| | - Alexander R Dunn
- Department of Chemical Engineering, Stanford University, Stanford, CA 94305
| | - Valerie M Weaver
- Center for Bioengineering and Tissue Regeneration, Department of Surgery, University of California, San Francisco, San Francisco, CA 94143 .,Departments of Anatomy, Bioengineering and Therapeutic Sciences, and Radiation Oncology, Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, and UCSF Helen Diller Comprehensive Cancer Center, University of California, San Francisco, San Francisco, CA 94143
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57
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Shurer CR, Colville MJ, Gupta VK, Head SE, Kai F, Lakins JN, Paszek MJ. Genetically Encoded Toolbox for Glycocalyx Engineering: Tunable Control of Cell Adhesion, Survival, and Cancer Cell Behaviors. ACS Biomater Sci Eng 2017; 4:388-399. [PMID: 29805991 DOI: 10.1021/acsbiomaterials.7b00037] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The glycocalyx is a coating of protein and sugar on the surface of all living cells. Dramatic perturbations to the composition and structure of the glycocalyx are frequently observed in aggressive cancers. However, tools to experimentally mimic and model the cancer-specific glycocalyx remain limited. Here, we develop a genetically encoded toolkit to engineer the chemical and physical structure of the cellular glycocalyx. By manipulating the glycocalyx structure, we are able to switch the adhesive state of cells from strongly adherent to fully detached. Surprisingly, we find that a thick and dense glycocalyx with high O-glycan content promotes cell survival even in a suspended state, characteristic of circulating tumor cells during metastatic dissemination. Our data suggest that glycocalyx-mediated survival is largely independent of receptor tyrosine kinase and mitogen activated kinase signaling. While anchorage is still required for proliferation, we find that cells with a thick glycocalyx can dynamically attach to a matrix scaffold, undergo cellular division, and quickly disassociate again into a suspended state. Together, our technology provides a needed toolkit for engineering the glycocalyx in glycobiology and cancer research.
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Affiliation(s)
- Carolyn R Shurer
- Robert Frederick Smith School of Chemical and Biomolecular Engineering, Cornell University, 113 Ho Plaza, Ithaca, New York 14853, United States
| | - Marshall J Colville
- Cornell University, Field of Biophysics, 107 Biotechnology Building, Ithaca, New York 14853, United States
| | - Vivek K Gupta
- Sibley School of Mechanical and Aerospace Engineering, Cornell University, 105 Upson Hall, Ithaca, New York 14853, United States
| | - Shelby E Head
- Robert Frederick Smith School of Chemical and Biomolecular Engineering, Cornell University, 113 Ho Plaza, Ithaca, New York 14853, United States
| | - FuiBoon Kai
- Center for Bioengineering and Tissue Regeneration, Department of Surgery, University of California, San Francisco, 513 Parnassus Avenue, San Francisco, California 94143, United States
| | - Jonathon N Lakins
- Center for Bioengineering and Tissue Regeneration, Department of Surgery, University of California, San Francisco, 513 Parnassus Avenue, San Francisco, California 94143, United States
| | - Matthew J Paszek
- Robert Frederick Smith School of Chemical and Biomolecular Engineering, Cornell University, 113 Ho Plaza, Ithaca, New York 14853, United States.,Cornell University, Field of Biophysics, 107 Biotechnology Building, Ithaca, New York 14853, United States.,Field of Biomedical Engineering, Cornell University, 101 Weill Hall, Ithaca, New York 14853, United States
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58
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Bertocchi C, Wang Y, Ravasio A, Hara Y, Wu Y, Sailov T, Baird MA, Davidson MW, Zaidel-Bar R, Toyama Y, Ladoux B, Mege RM, Kanchanawong P. Nanoscale architecture of cadherin-based cell adhesions. Nat Cell Biol 2017; 19:28-37. [PMID: 27992406 PMCID: PMC5421576 DOI: 10.1038/ncb3456] [Citation(s) in RCA: 107] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Accepted: 11/18/2016] [Indexed: 12/13/2022]
Abstract
Multicellularity in animals requires dynamic maintenance of cell-cell contacts. Intercellularly ligated cadherins recruit numerous proteins to form supramolecular complexes that connect with the actin cytoskeleton and support force transmission. However, the molecular organization within such structures remains unknown. Here we mapped protein organization in cadherin-based adhesions by super-resolution microscopy, revealing a multi-compartment nanoscale architecture, with the plasma-membrane-proximal cadherin-catenin compartment segregated from the actin cytoskeletal compartment, bridged by an interface zone containing vinculin. Vinculin position is determined by α-catenin, and following activation, vinculin can extend ∼30 nm to bridge the cadherin-catenin and actin compartments, while modulating the nanoscale positions of the actin regulators zyxin and VASP. Vinculin conformational activation requires tension and tyrosine phosphorylation, regulated by Abl kinase and PTP1B phosphatase. Such modular architecture provides a structural framework for mechanical and biochemical signal integration by vinculin, which may differentially engage cadherin-catenin complexes with the actomyosin machinery to regulate cell adhesions.
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Affiliation(s)
| | - Yilin Wang
- Mechanobiology Institute, Singapore, Republic of Singapore, 117411
| | - Andrea Ravasio
- Mechanobiology Institute, Singapore, Republic of Singapore, 117411
| | - Yusuke Hara
- Mechanobiology Institute, Singapore, Republic of Singapore, 117411
| | - Yao Wu
- Mechanobiology Institute, Singapore, Republic of Singapore, 117411
| | - Talgat Sailov
- Mechanobiology Institute, Singapore, Republic of Singapore, 117411
| | - Michelle A. Baird
- National High Magnetic Field Laboratory, The Florida State University, Tallahassee, FL, USA, 32310
| | - Michael W. Davidson
- National High Magnetic Field Laboratory, The Florida State University, Tallahassee, FL, USA, 32310
- Department of Biological Science, The Florida State University, Tallahassee, FL, USA, 32306
| | - Ronen Zaidel-Bar
- Mechanobiology Institute, Singapore, Republic of Singapore, 117411
- Department of Biomedical Engineering, National University of Singapore, Republic of Singapore, 117583
| | - Yusuke Toyama
- Mechanobiology Institute, Singapore, Republic of Singapore, 117411
- Department of Biological Sciences, National University of Singapore, Singapore, Republic of Singapore, 117543
- Temasek Life Sciences Laboratory, National University of Singapore, Singapore, Republic of Singapore, 117604
| | - Benoit Ladoux
- Mechanobiology Institute, Singapore, Republic of Singapore, 117411
- Institut Jacques Monod, Université Paris Diderot and CNRS UMR 7592, Paris, France
| | - Rene-Marc Mege
- Institut Jacques Monod, Université Paris Diderot and CNRS UMR 7592, Paris, France
| | - Pakorn Kanchanawong
- Mechanobiology Institute, Singapore, Republic of Singapore, 117411
- Department of Biomedical Engineering, National University of Singapore, Republic of Singapore, 117583
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59
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Cardoso Dos Santos M, Vézy C, Morjani H, Jaffol R. Single cell adhesion strength assessed with variable-angle total internal reflection fluorescence microscopy. AIMS BIOPHYSICS 2017. [DOI: 10.3934/biophy.2017.3.438] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
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60
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Ou G, Thakar D, Tung JC, Miroshnikova YA, Dufort CC, Gutierrez E, Groisman A, Weaver VM. Visualizing mechanical modulation of nanoscale organization of cell-matrix adhesions. Integr Biol (Camb) 2016; 8:795-804. [PMID: 27334548 PMCID: PMC4980125 DOI: 10.1039/c6ib00031b] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
The mechanical properties of the extracellular matrix influence cell signaling to regulate key cellular processes, including differentiation, apoptosis, and transformation. Understanding the molecular mechanisms underlying mechanotransduction is contingent upon our ability to visualize the effect of altered matrix properties on the nanoscale organization of proteins involved in this signalling. The development of super-resolution imaging techniques has afforded researchers unprecedented ability to probe the organization and localization of proteins within the cell. However, most of these methods require use of substrates like glass or silicon wafers, which are artificially rigid. In light of a growing body of literature demonstrating the importance of mechanical properties of the extracellular matrix in regulating many aspects of cellular behavior and signaling, we have developed a system that allows scanning angle interference microscopy on a mechanically tunable substrate. We describe its implementation in detail and provide examples of how it may be used to aide investigations into the effect of substrate rigidity on intracellular signaling.
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Affiliation(s)
- Guanqing Ou
- University of California, Berkeley and University of California, San Francisco Joint Graduate Group in Bioengineering, San Francisco, CA, USA
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61
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Biswas KH, Groves JT. A Microbead Supported Membrane-Based Fluorescence Imaging Assay Reveals Intermembrane Receptor-Ligand Complex Dimension with Nanometer Precision. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:6775-6780. [PMID: 27264296 DOI: 10.1021/acs.langmuir.6b01377] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Receptor-ligand complexes spanning a cell-cell interface inevitably establish a preferred intermembrane spacing based on the molecular dimensions and orientation of the complexes. This couples molecular binding events to membrane mechanics and large-scale spatial organization of receptors on the cell surface. Here, we describe a straightforward, epi-fluorescence-based method to precisely determine intermembrane receptor-ligand dimension at adhesions established by receptor-ligand binding between apposed membranes in vitro. Adhesions were reconstituted between planar and silica microbead supported membranes via specific interaction between cognate receptor/ligand pairs (EphA2/EphrinA1 and E-cadherin/anti-E-cadherin antibody). Epi-fluorescence imaging of the ligand enrichment zone in the supported membrane beneath the adhering microbead, combined with a simple geometrical interpretation, proves sufficient to estimate intermembrane receptor-ligand dimension with better than 1 nm precision. An advantage of this assay is that no specialized equipment or imaging methods are required.
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Affiliation(s)
- Kabir H Biswas
- Mechanobiology Institute, National University of Singapore , Singapore 117411, Singapore
| | - Jay T Groves
- Mechanobiology Institute, National University of Singapore , Singapore 117411, Singapore
- Department of Chemistry, University of California , Berkeley, California 94720, United States
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62
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Bhagawati M, Rubashkin MG, Lee JP, Ananthanarayanan B, Weaver VM, Kumar S. Site-Specific Modulation of Charge Controls the Structure and Stimulus Responsiveness of Intrinsically Disordered Peptide Brushes. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:5990-5996. [PMID: 27203736 PMCID: PMC5343758 DOI: 10.1021/acs.langmuir.6b01099] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Intrinsically disordered proteins (IDPs) are an important and emerging class of materials for tailoring biointerfaces. While the importance of chain charge and resultant electrostatic interactions in controlling conformational properties of IDPs is beginning to be explored through in silico approaches, there is a dearth of experimental studies motivated toward a systematic study of these effects. In an effort to explore this relationship, we measured the conformations of two peptides derived from the intrinsically disordered neurofilament (NF) side arm domain: one depicting the wild-type sequence with four lysine-serine-proline repeats (KSP peptide) and another in which the serine residues were replaced with aspartates (KDP peptide), a strategy sometimes used to mimic phosphorylation. Using a variety of biophysical measurements including a novel application of scanning angle interference microscopy, we demonstrate that the KDP peptide assumes comparatively more expanded conformations in solution and forms significantly thicker brushes when immobilized on planar surfaces at high densities. In both settings, the peptides respond to changes in ambient ionic strength, with each peptide showing distinct stimulus-responsive characteristics. While the KDP peptide undergoes compaction with increasing ionic strength as would be expected for a polyampholyte, the KSP peptide shows biphasic behavior, with an initial compaction followed by an expanded state at a higher ionic strength. Together these results support the notion that modulation of charge on IDPs can regulate conformational and interfacial properties.
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Affiliation(s)
- Maniraj Bhagawati
- Department of Bioengineering, University of California, Berkeley, Berkeley, California 94720, United States
| | - Matt G. Rubashkin
- Center for Bioengineering and Tissue Regeneration, University of California, San Francisco, San Francisco, California 94143, United States
- UC Berkeley-UCSF Graduate Program in Bioengineering, University of California, Berkeley, Berkeley, California 94720, United States
| | - Jessica P. Lee
- Department of Bioengineering, University of California, Berkeley, Berkeley, California 94720, United States
- Department of Chemistry, University of California, Berkeley, Berkeley, California 94720, United States
| | | | - Valerie M. Weaver
- Center for Bioengineering and Tissue Regeneration, University of California, San Francisco, San Francisco, California 94143, United States
- UC Berkeley-UCSF Graduate Program in Bioengineering, University of California, Berkeley, Berkeley, California 94720, United States
| | - Sanjay Kumar
- Department of Bioengineering, University of California, Berkeley, Berkeley, California 94720, United States
- UC Berkeley-UCSF Graduate Program in Bioengineering, University of California, Berkeley, Berkeley, California 94720, United States
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, Berkeley, California 94720, United States
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63
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Rossier O, Giannone G. The journey of integrins and partners in a complex interactions landscape studied by super-resolution microscopy and single protein tracking. Exp Cell Res 2016; 343:28-34. [DOI: 10.1016/j.yexcr.2015.11.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Accepted: 11/05/2015] [Indexed: 10/24/2022]
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64
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Axial superresolution via multiangle TIRF microscopy with sequential imaging and photobleaching. Proc Natl Acad Sci U S A 2016; 113:4368-73. [PMID: 27044072 DOI: 10.1073/pnas.1516715113] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We report superresolution optical sectioning using a multiangle total internal reflection fluorescence (TIRF) microscope. TIRF images were constructed from several layers within a normal TIRF excitation zone by sequentially imaging and photobleaching the fluorescent molecules. The depth of the evanescent wave at different layers was altered by tuning the excitation light incident angle. The angle was tuned from the highest (the smallest TIRF depth) toward the critical angle (the largest TIRF depth) to preferentially photobleach fluorescence from the lower layers and allow straightforward observation of deeper structures without masking by the brighter signals closer to the coverglass. Reconstruction of the TIRF images enabled 3D imaging of biological samples with 20-nm axial resolution. Two-color imaging of epidermal growth factor (EGF) ligand and clathrin revealed the dynamics of EGF-activated clathrin-mediated endocytosis during internalization. Furthermore, Bayesian analysis of images collected during the photobleaching step of each plane enabled lateral superresolution (<100 nm) within each of the sections.
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65
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Abstract
Mechanical stimuli are known to be potent regulators of the form and function of cells and organisms. Although biological regulation has classically been understood in terms of principles from solution biochemistry, advancements in many fields have led to the development of a suite of techniques that are able to reveal the interplay between mechanical loading and changes in the biochemical properties of proteins in systems ranging from single molecules to living organisms. Here, we review these techniques and highlight the emergence of a new molecular-scale understanding of the mechanisms mediating the detection and response of cells to mechanical stimuli, a process termed mechanotransduction. Specifically, we focus on the role of subcellular adhesion structures in sensing the stiffness of the surrounding environment because this process is pertinent to applications in tissue engineering as well the onset of several mechanosensitive disease states, including cancer.
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Affiliation(s)
- Andrew S LaCroix
- Department of Biomedical Engineering, Duke University, Durham, North Carolina 27708;
| | - Katheryn E Rothenberg
- Department of Biomedical Engineering, Duke University, Durham, North Carolina 27708;
| | - Brenton D Hoffman
- Department of Biomedical Engineering, Duke University, Durham, North Carolina 27708;
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66
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Abstract
The physical and biochemical properties of the microenvironment regulate cell behavior and modulate tissue development and homeostasis. Likewise, the physical and interpersonal cues a trainee receives profoundly influence his or her scientific development, research perspective, and future success. My cell biology career has been greatly impacted by the flavor of the scientific environments I have trained within and the diverse research mentoring I have received. Interactions with physical and life scientists and trainees and exposure to a diverse assortment of interdisciplinary environments have and continue to shape my research vision, guide my experimental trajectory, and contribute to my scientific success and personal happiness.
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Affiliation(s)
- Valerie Marie Weaver
- Center for Bioengineering and Tissue Regeneration, Department of Surgery, and Departments of Anatomy and Bioengineering and Therapeutic Sciences, Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, and UCSF Helen Diller Comprehensive Cancer Center, University of California, San Francisco, San Francisco, CA 94143
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67
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Stabley DR, Oh T, Simon SM, Mattheyses AL, Salaita K. Real-time fluorescence imaging with 20 nm axial resolution. Nat Commun 2015; 6:8307. [PMID: 26392382 PMCID: PMC4595625 DOI: 10.1038/ncomms9307] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2015] [Accepted: 08/07/2015] [Indexed: 11/09/2022] Open
Abstract
Measuring the nanoscale organization of protein structures near the plasma membrane of live cells is challenging, especially when the structure is dynamic. Here we present the development of a two-wavelength total internal reflection fluorescence method capable of real-time imaging of cellular structure height with nanometre resolution. The method employs a protein of interest tagged with two different fluorophores and imaged to obtain the ratio of emission in the two channels. We use this approach to visualize the nanoscale organization of microtubules and endocytosis of the epidermal growth factor receptor.
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Affiliation(s)
- Daniel R Stabley
- Department of Chemistry, Emory University, Atlanta, Georgia 30322, USA
| | - Thomas Oh
- Laboratory of Cellular Biophysics, The Rockefeller University, New York, New York 10065, USA
| | - Sanford M Simon
- Laboratory of Cellular Biophysics, The Rockefeller University, New York, New York 10065, USA
| | - Alexa L Mattheyses
- Department of Cell Biology, Emory University School of Medicine, Atlanta, Georgia 30322, USA
| | - Khalid Salaita
- Department of Chemistry, Emory University, Atlanta, Georgia 30322, USA
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68
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Abstract
Insight into how molecular machines perform their biological functions depends on knowledge of the spatial organization of the components, their connectivity, geometry, and organizational hierarchy. However, these parameters are difficult to determine in multicomponent assemblies such as integrin-based focal adhesions (FAs). We have previously applied 3D superresolution fluorescence microscopy to probe the spatial organization of major FA components, observing a nanoscale stratification of proteins between integrins and the actin cytoskeleton. Here we combine superresolution imaging techniques with a protein engineering approach to investigate how such nanoscale architecture arises. We demonstrate that talin plays a key structural role in regulating the nanoscale architecture of FAs, akin to a molecular ruler. Talin diagonally spans the FA core, with its N terminus at the membrane and C terminus demarcating the FA/stress fiber interface. In contrast, vinculin is found to be dispensable for specification of FA nanoscale architecture. Recombinant analogs of talin with modified lengths recapitulated its polarized orientation but altered the FA/stress fiber interface in a linear manner, consistent with its modular structure, and implicating the integrin-talin-actin complex as the primary mechanical linkage in FAs. Talin was found to be ∼97 nm in length and oriented at ∼15° relative to the plasma membrane. Our results identify talin as the primary determinant of FA nanoscale organization and suggest how multiple cellular forces may be integrated at adhesion sites.
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69
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Integration of actin dynamics and cell adhesion by a three-dimensional, mechanosensitive molecular clutch. Nat Cell Biol 2015; 17:955-63. [PMID: 26121555 DOI: 10.1038/ncb3191] [Citation(s) in RCA: 330] [Impact Index Per Article: 36.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Accepted: 05/15/2015] [Indexed: 12/12/2022]
Abstract
During cell migration, the forces generated in the actin cytoskeleton are transmitted across transmembrane receptors to the extracellular matrix or other cells through a series of mechanosensitive, regulable protein-protein interactions termed the molecular clutch. In integrin-based focal adhesions, the proteins forming this linkage are organized into a conserved three-dimensional nano-architecture. Here we discuss how the physical interactions between the actin cytoskeleton and focal-adhesion-associated molecules mediate force transmission from the molecular clutch to the extracellular matrix.
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70
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Rubashkin MG, Cassereau L, Bainer R, DuFort CC, Yui Y, Ou G, Paszek MJ, Davidson MW, Chen YY, Weaver VM. Force engages vinculin and promotes tumor progression by enhancing PI3K activation of phosphatidylinositol (3,4,5)-triphosphate. Cancer Res 2015; 74:4597-611. [PMID: 25183785 DOI: 10.1158/0008-5472.can-13-3698] [Citation(s) in RCA: 153] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Extracellular matrix (ECM) stiffness induces focal adhesion assembly to drive malignant transformation and tumor metastasis. Nevertheless, how force alters focal adhesions to promote tumor progression remains unclear. Here, we explored the role of the focal adhesion protein vinculin, a force-activated mechanotransducer, in mammary epithelial tissue transformation and invasion. We found that ECM stiffness stabilizes the assembly of a vinculin-talin-actin scaffolding complex that facilitates PI3K-mediated phosphatidylinositol (3,4,5)-triphosphate phosphorylation. Using defined two- and three-dimensional matrices, a mouse model of mammary tumorigenesis with vinculin mutants, and a novel super resolution imaging approach, we established that ECM stiffness, per se, promotes the malignant progression of a mammary epithelium by activating and stabilizing vinculin and enhancing Akt signaling at focal adhesions. Our studies also revealed that vinculin strongly colocalizes with activated Akt at the invasive border of human breast tumors, where the ECM is stiffest, and we detected elevated mechanosignaling. Thus, ECM stiffness could induce tumor progression by promoting the assembly of signaling scaffolds, a conclusion underscored by the significant association we observed between highly expressed focal adhesion plaque proteins and malignant transformation across multiple types of solid cancer. See all articles in this Cancer Research section, "Physics in Cancer Research."
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Affiliation(s)
- Matthew G Rubashkin
- Center for Bioengineering and Tissue Regeneration, Department of Surgery, UCSF, San Francisco, California
| | - Luke Cassereau
- Center for Bioengineering and Tissue Regeneration, Department of Surgery, UCSF, San Francisco, California
| | - Russell Bainer
- Center for Bioengineering and Tissue Regeneration, Department of Surgery, UCSF, San Francisco, California
| | - Christopher C DuFort
- Center for Bioengineering and Tissue Regeneration, Department of Surgery, UCSF, San Francisco, California
| | - Yoshihiro Yui
- Center for Bioengineering and Tissue Regeneration, Department of Surgery, UCSF, San Francisco, California
| | - Guanqing Ou
- Center for Bioengineering and Tissue Regeneration, Department of Surgery, UCSF, San Francisco, California
| | - Matthew J Paszek
- Center for Bioengineering and Tissue Regeneration, Department of Surgery, UCSF, San Francisco, California. Kavli Institute at Cornell for Nanoscale Science, Cornell University, Ithaca, New York
| | - Michael W Davidson
- National High Magnetic Field Laboratory and Department of Biological Science, Florida State University, Tallahassee, Florida
| | - Yunn-Yi Chen
- Department of Pathology, UCSF, San Francisco, California
| | - Valerie M Weaver
- Center for Bioengineering and Tissue Regeneration, Department of Surgery, UCSF, San Francisco, California. Department of Pathology, UCSF, San Francisco, California. Departments of Anatomy and Bioengineering and Therapeutic Sciences, Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, and UCSF Helen Diller Comprehensive Cancer Center, UCSF, San Francisco, California.
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71
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Klapholz B, Herbert SL, Wellmann J, Johnson R, Parsons M, Brown NH. Alternative mechanisms for talin to mediate integrin function. Curr Biol 2015; 25:847-57. [PMID: 25754646 PMCID: PMC4386027 DOI: 10.1016/j.cub.2015.01.043] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Revised: 01/19/2015] [Accepted: 01/19/2015] [Indexed: 02/06/2023]
Abstract
Cell-matrix adhesion is essential for building animals, promoting tissue cohesion, and enabling cells to migrate and resist mechanical force. Talin is an intracellular protein that is critical for linking integrin extracellular-matrix receptors to the actin cytoskeleton. A key question raised by structure-function studies is whether talin, which is critical for all integrin-mediated adhesion, acts in the same way in every context. We show that distinct combinations of talin domains are required for each of three different integrin functions during Drosophila development. The partial function of some mutant talins requires vinculin, indicating that recruitment of vinculin allows talin to duplicate its own activities. The different requirements are best explained by alternative mechanisms of talin function, with talin using one or both of its integrin-binding sites. We confirmed these alternatives by showing that the proximity between the second integrin-binding site and integrins differs, suggesting that talin adopts different orientations relative to integrins. Finally, we show that vinculin and actomyosin activity help change talin’s orientation. These findings demonstrate that the mechanism of talin function differs in each developmental context examined. The different arrangements of the talin molecule relative to integrins suggest that talin is able to sense different force vectors, either parallel or perpendicular to the membrane. This provides a paradigm for proteins whose apparent uniform function is in fact achieved by a variety of distinct mechanisms involving different molecular architectures. Integrin function requires distinct sets of talin domains in three different tissues Vinculin helps talin retain function when domains are removed Talin IBS2 is separated from integrins in muscle but not wing adhesion sites Vinculin and actomyosin contribute to separating IBS2 from integrins
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Affiliation(s)
- Benjamin Klapholz
- The Gurdon Institute and Department of Physiology, Development and Neuroscience, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK
| | - Samantha L Herbert
- The Gurdon Institute and Department of Physiology, Development and Neuroscience, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK
| | - Jutta Wellmann
- The Gurdon Institute and Department of Physiology, Development and Neuroscience, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK
| | - Robert Johnson
- The Gurdon Institute and Department of Physiology, Development and Neuroscience, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK
| | - Maddy Parsons
- Randall Division of Cell and Molecular Biophysics, King's College London, London SE1 1UL, UK
| | - Nicholas H Brown
- The Gurdon Institute and Department of Physiology, Development and Neuroscience, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK.
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72
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Abstract
Fluorescence microscopy is among the most widely utilized tools in cell and molecular biology due to its ability to noninvasively obtain time-resolved images of live cells with molecule-specific contrast. In this chapter, we describe a simple high-resolution technique, scanning angle interference microscopy (SAIM), for the imaging and localization of fluorescent molecules with nanometer precision along the optical axis. In SAIM, samples above a reflective surface are sequentially scanned with an excitation laser at varying angles of incidence. Interference patterns generated between the incident and reflected lights result in an emission intensity that depends on the height of a fluorophore above the silicon surface and the angle of the incident radiation. The measured fluorescence intensities are then fit to an optical model to localize the labeled molecules along the z-axis with 5-10 nm precision and diffraction-limited lateral resolution. SAIM is easily implemented on widely available commercial total internal reflection fluorescence microscopes, offering potential for widespread use in cell biology. Here, we describe the setup of SAIM and its application for imaging cellular structures near (<1 μm) the sample substrate.
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73
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Brodovitch A, Limozin L, Bongrand P, Pierres A. Use of TIRF to Monitor T-Lymphocyte Membrane Dynamics with Submicrometer and Subsecond Resolution. Cell Mol Bioeng 2014; 8:178-186. [PMID: 25798205 PMCID: PMC4361759 DOI: 10.1007/s12195-014-0361-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Accepted: 10/04/2014] [Indexed: 11/29/2022] Open
Abstract
A key step of adaptive immune responses is the T lymphocyte capacity to detect the presence of foreign antigens on specialized cells with high speed and specificity during contacts lasting a few minutes. Much evidence suggests that there is a deep link between the lifetime of molecular interactions between T cell receptors and ligands and T cell activation, but the precise mechanisms of bond formation and dissociation remain incompletely understood. Previous experiments done with interference reflection microscopy/reflection interference contrast microscopy disclosed transverse motions with several nanometer average amplitude of micrometer size membrane zones. More recently, total internal reflection fluorescence microscopy was used to show that the initial interaction between primary T lymphocytes and model surfaces involved the tip of microvilli (typically 0.2 µm2 area) generating apparent contacts of a few seconds that allowed cells to detect ligands of their membrane receptors. Here we show that these microvilli displayed minimal lateral displacements but quantitative fluorescence measurement suggested the occurrence of spontaneous transverse fluctuations of order of 67 nm amplitude during 1-s observation periods. This may play a major role in membrane receptor engagement and ensuing signal generation.
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Affiliation(s)
- Alexandre Brodovitch
- Laboratoire Adhésion et Inflammation, Parc Scientifique de Luminy, Aix-Marseille Université, INSERM U1067, Case 937, 13288 Marseille Cedex 09, France ; INSERM U 1067, 13288 Marseille Cedex 09, France ; CNRS U 7333, 13288 Marseille Cedex 09, France
| | - Laurent Limozin
- Laboratoire Adhésion et Inflammation, Parc Scientifique de Luminy, Aix-Marseille Université, INSERM U1067, Case 937, 13288 Marseille Cedex 09, France ; INSERM U 1067, 13288 Marseille Cedex 09, France ; CNRS U 7333, 13288 Marseille Cedex 09, France
| | - Pierre Bongrand
- Laboratoire Adhésion et Inflammation, Parc Scientifique de Luminy, Aix-Marseille Université, INSERM U1067, Case 937, 13288 Marseille Cedex 09, France ; INSERM U 1067, 13288 Marseille Cedex 09, France ; CNRS U 7333, 13288 Marseille Cedex 09, France ; Assistance-Publique, Hôpitaux de Marseille, Marseille, France
| | - Anne Pierres
- Laboratoire Adhésion et Inflammation, Parc Scientifique de Luminy, Aix-Marseille Université, INSERM U1067, Case 937, 13288 Marseille Cedex 09, France ; INSERM U 1067, 13288 Marseille Cedex 09, France ; CNRS U 7333, 13288 Marseille Cedex 09, France
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74
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Oakes PW, Gardel ML. Stressing the limits of focal adhesion mechanosensitivity. Curr Opin Cell Biol 2014; 30:68-73. [PMID: 24998185 DOI: 10.1016/j.ceb.2014.06.003] [Citation(s) in RCA: 96] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2014] [Revised: 06/10/2014] [Accepted: 06/11/2014] [Indexed: 01/09/2023]
Abstract
Focal adhesion assembly and maturation often occurs concomitantly with changes in force generated within the cytoskeleton or extracellular matrix. To coordinate focal adhesion dynamics with force, it has been suggested that focal adhesion dynamics are mechanosensitive. This review discusses current understanding of the regulation of focal adhesion assembly and force transmission, and the limits to which we can consider focal adhesion plaques as mechanosensitive entities.
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Affiliation(s)
- Patrick W Oakes
- James Franck Institute, Institute for Biophysical Dynamics and Physics Department, University of Chicago, Chicago, IL, United States
| | - Margaret L Gardel
- James Franck Institute, Institute for Biophysical Dynamics and Physics Department, University of Chicago, Chicago, IL, United States.
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75
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The cancer glycocalyx mechanically primes integrin-mediated growth and survival. Nature 2014; 511:319-25. [PMID: 25030168 DOI: 10.1038/nature13535] [Citation(s) in RCA: 490] [Impact Index Per Article: 49.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2013] [Accepted: 05/23/2014] [Indexed: 12/27/2022]
Abstract
Malignancy is associated with altered expression of glycans and glycoproteins that contribute to the cellular glycocalyx. We constructed a glycoprotein expression signature, which revealed that metastatic tumours upregulate expression of bulky glycoproteins. A computational model predicted that these glycoproteins would influence transmembrane receptor spatial organization and function. We tested this prediction by investigating whether bulky glycoproteins in the glycocalyx promote a tumour phenotype in human cells by increasing integrin adhesion and signalling. Our data revealed that a bulky glycocalyx facilitates integrin clustering by funnelling active integrins into adhesions and altering integrin state by applying tension to matrix-bound integrins, independent of actomyosin contractility. Expression of large tumour-associated glycoproteins in non-transformed mammary cells promoted focal adhesion assembly and facilitated integrin-dependent growth factor signalling to support cell growth and survival. Clinical studies revealed that large glycoproteins are abundantly expressed on circulating tumour cells from patients with advanced disease. Thus, a bulky glycocalyx is a feature of tumour cells that could foster metastasis by mechanically enhancing cell-surface receptor function.
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76
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Stehbens SJ, Paszek M, Pemble H, Ettinger A, Gierke S, Wittmann T. CLASPs link focal-adhesion-associated microtubule capture to localized exocytosis and adhesion site turnover. Nat Cell Biol 2014; 16:561-73. [PMID: 24859005 PMCID: PMC4108447 DOI: 10.1038/ncb2975] [Citation(s) in RCA: 185] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2014] [Accepted: 04/24/2014] [Indexed: 12/14/2022]
Abstract
Turnover of integrin-based focal adhesions (FAs) with the extracellular matrix (ECM) is essential for coordinated cell movement. In collectively migrating human keratinocytes, FAs assemble near the leading edge, grow and mature as a result of contractile forces, and disassemble underneath the advancing cell body. We report that clustering of microtubule-associated CLASP1 and CLASP2 proteins around FAs temporally correlates with FA turnover. CLASPs and LL5β, which recruits CLASPs to FAs, facilitate FA disassembly. CLASPs are further required for FA-associated ECM degradation, and matrix metalloprotease inhibition slows FA disassembly similar to CLASP or LL5β depletion. Finally, CLASP-mediated microtubuletethering at FAs establishes a FA-directed transport pathway for delivery, docking and localized fusion of exocytic vesicles near FAs. We propose that CLASPs couple microtubule organization, vesicle transport and cell interactions with the ECM, establishing a local secretion pathway that facilitates FA turnover by severing cell-matrix connections.
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Affiliation(s)
- Samantha J Stehbens
- 1] Department of Cell and Tissue Biology, University of California San Francisco, 513 Parnassus Avenue San Francisco, California 94143, USA [2]
| | - Matthew Paszek
- 1] Department of Surgery and Center for Bioengineering and Tissue Regeneration, University of California San Francisco, 513 Parnassus Avenue San Francisco, California 94143, USA [2]
| | - Hayley Pemble
- Department of Cell and Tissue Biology, University of California San Francisco, 513 Parnassus Avenue San Francisco, California 94143, USA
| | - Andreas Ettinger
- Department of Cell and Tissue Biology, University of California San Francisco, 513 Parnassus Avenue San Francisco, California 94143, USA
| | - Sarah Gierke
- Department of Cell and Tissue Biology, University of California San Francisco, 513 Parnassus Avenue San Francisco, California 94143, USA
| | - Torsten Wittmann
- Department of Cell and Tissue Biology, University of California San Francisco, 513 Parnassus Avenue San Francisco, California 94143, USA
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77
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Sackmann E, Smith AS. Physics of cell adhesion: some lessons from cell-mimetic systems. SOFT MATTER 2014; 10:1644-59. [PMID: 24651316 PMCID: PMC4028615 DOI: 10.1039/c3sm51910d] [Citation(s) in RCA: 85] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Cell adhesion is a paradigm of the ubiquitous interplay of cell signalling, modulation of material properties and biological functions of cells. It is controlled by competition of short range attractive forces, medium range repellant forces and the elastic stresses associated with local and global deformation of the composite cell envelopes. We review the basic physical rules governing the physics of cell adhesion learned by studying cell-mimetic systems and demonstrate the importance of these rules in the context of cellular systems. We review how adhesion induced micro-domains couple to the intracellular actin and microtubule networks allowing cells to generate strong forces with a minimum of attractive cell adhesion molecules (CAMs) and to manipulate other cells through filopodia over micrometer distances. The adhesion strength can be adapted to external force fluctuations within seconds by varying the density of attractive and repellant CAMs through exocytosis and endocytosis or protease-mediated dismantling of the CAM-cytoskeleton link. Adhesion domains form local end global biochemical reaction centres enabling the control of enzymes. Actin-microtubule crosstalk at adhesion foci facilitates the mechanical stabilization of polarized cell shapes. Axon growth in tissue is guided by attractive and repulsive clues controlled by antagonistic signalling pathways.
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Affiliation(s)
- Erich Sackmann
- Physics Department Technical University Munich, Germany
- Department of Physics, Ludwig-Maximillian University, Munich, Germany
| | - Ana-Sunčana Smith
- Institute for Theoretical Physics, Friedrich Alexander University Erlangen-Nürnberg, Erlangen, Germany
- Institute Rud̷er Bošković, Zagreb, Croatia.
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78
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Mouw JK, Yui Y, Damiano L, Bainer RO, Lakins JN, Acerbi I, Ou G, Wijekoon AC, Levental KR, Gilbert PM, Hwang ES, Chen YY, Weaver VM. Tissue mechanics modulate microRNA-dependent PTEN expression to regulate malignant progression. Nat Med 2014; 20:360-7. [PMID: 24633304 PMCID: PMC3981899 DOI: 10.1038/nm.3497] [Citation(s) in RCA: 301] [Impact Index Per Article: 30.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2013] [Accepted: 02/10/2014] [Indexed: 12/15/2022]
Abstract
Tissue mechanics regulate development and homeostasis and are consistently modified in tumor progression. Nevertheless, the fundamental molecular mechanisms through which altered mechanics regulate tissue behavior and the clinical relevance of these changes remain unclear. We demonstrate that increased matrix stiffness modulates microRNA expression to drive tumor progression through integrin activation of β-catenin and MYC. Specifically, in human and mouse tissue, increased matrix stiffness induced miR-18a to reduce levels of the tumor suppressor PTEN, both directly and indirectly by decreasing levels of HOXA9. Clinically, extracellular matrix stiffness correlated significantly with miR-18a in human breast tumor biopsies. miR-18a expression was highest in basal-like breast cancers in which PTEN and HOXA9 levels were lowest and predicted for poor prognosis in patients with luminal breast cancers. Our findings identify a mechanically-regulated microRNA circuit that can promote malignancy and suggest potential prognostic roles for HOXA9 and miR-18a levels in stratifying patients with luminal breast cancers.
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Affiliation(s)
- Janna K Mouw
- Center for Bioengineering and Tissue Regeneration, Department of Surgery, University of California San Francisco (UCSF), San Francisco, California, USA
| | - Yoshihiro Yui
- Center for Bioengineering and Tissue Regeneration, Department of Surgery, University of California San Francisco (UCSF), San Francisco, California, USA
| | - Laura Damiano
- Center for Bioengineering and Tissue Regeneration, Department of Surgery, University of California San Francisco (UCSF), San Francisco, California, USA
| | - Russell O Bainer
- Center for Bioengineering and Tissue Regeneration, Department of Surgery, University of California San Francisco (UCSF), San Francisco, California, USA
| | - Johnathon N Lakins
- Center for Bioengineering and Tissue Regeneration, Department of Surgery, University of California San Francisco (UCSF), San Francisco, California, USA
| | - Irene Acerbi
- Center for Bioengineering and Tissue Regeneration, Department of Surgery, University of California San Francisco (UCSF), San Francisco, California, USA
| | - Guanqing Ou
- Center for Bioengineering and Tissue Regeneration, Department of Surgery, University of California San Francisco (UCSF), San Francisco, California, USA
| | - Amanda C Wijekoon
- Center for Bioengineering and Tissue Regeneration, Department of Surgery, University of California San Francisco (UCSF), San Francisco, California, USA
| | - Kandice R Levental
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center at Houston-Medical School, Houston, Texas, USA
| | - Penney M Gilbert
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada
| | - E Shelley Hwang
- Department of Surgery, Duke University Comprehensive Cancer Center, Durham, North Carolina, USA
| | - Yunn-Yi Chen
- Department of Pathology, UCSF, San Francisco, California, USA
| | - Valerie M Weaver
- 1] Center for Bioengineering and Tissue Regeneration, Department of Surgery, University of California San Francisco (UCSF), San Francisco, California, USA. [2] Department of Anatomy and Department of Bioengineering and Therapeutic Sciences, UCSF, San Francisco, California, USA. [3] Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, UCSF, San Francisco, California, USA. [4] UCSF Helen Diller Comprehensive Cancer Center, UCSF, San Francisco, California, USA
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79
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Abstract
Spatially patterned subtractive de-inking, a process we term "stamp-off," provides a simple method to generate sparse, multicomponent protein micropatterns. It has been applied to control cell adhesion, study adhesion biology, as well as to micropattern fragile surfaces. This technique can also readily be applied to study nanoscale interactions between cell membrane receptors and surface-immobilized ligands. It is based on conventional microcontact printing and as such requires the same reagents, including photolithographically defined masters, a spin-coater, poly(dimethyl siloxane) (PDMS), and conventional cell culture reagents such as glass coverslips and adhesive proteins. Stamp-off is conceptually simplified into three steps: (1) generation of an appropriate cell culture substrate, PDMS-coated glass, (2) micropatterning with stamp-off, and (3) cell deposition. After elaborating each of these three methods, we discuss limitations of the technique and its applications.
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Affiliation(s)
- Ravi A Desai
- Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania USA; Max Planck Institute for Molecular Cell Biology and Genetics, Dresden, Germany; Medical Research Council, National Institute of Medical Research, London, United Kingdom; University College London, London, United Kingdom
| | - Natalia M Rodriguez
- Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania USA; Department of Biomedical Engineering, Boston University, Boston, Massachusetts, USA; Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, Massachusetts, USA
| | - Christopher S Chen
- Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania USA; Department of Biomedical Engineering, Boston University, Boston, Massachusetts, USA; Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, Massachusetts, USA
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80
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Spectrally coded optical nanosectioning (SpecON) with biocompatible metal-dielectric-coated substrates. Proc Natl Acad Sci U S A 2013; 110:20069-74. [PMID: 24277837 DOI: 10.1073/pnas.1307222110] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Fluorescence nanosectioning within a submicron region above an interface is desirable for many disciplines in the life sciences. A drawback, however, to most current approaches is the a priori need to physically scan a sculptured point spread function in the axial dimension, which can be undesirable for optically sensitive or highly dynamic samples. Here we demonstrate a fluorescence imaging approach that can overcome the need for scanning by exploiting the position-dependent emission spectrum of fluorophores above a simple biocompatible nanostructure. To achieve this we have designed a thin metal-dielectric-coated substrate, where the spectral modification to the total measured fluorescence can be used to estimate the axial fluorophore distribution within distances of 10-150 nm above the substrate with an accuracy of up to 5-10 nm. The modeling and feasibility of the approach are verified and successfully applied to elucidate nanoscale adhesion protein and filopodia dynamics in migrating cells. It is likely that the general principle can find broader applications in, for example, single-molecule studies, biosensing, and studying fast dynamic processes.
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81
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Actin in action: imaging approaches to study cytoskeleton structure and function. Cells 2013; 2:715-31. [PMID: 24709877 PMCID: PMC3972653 DOI: 10.3390/cells2040715] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2013] [Revised: 11/06/2013] [Accepted: 11/08/2013] [Indexed: 01/18/2023] Open
Abstract
The cytoskeleton plays several fundamental roles in the cell, including organizing the spatial arrangement of subcellular organelles, regulating cell dynamics and motility, providing a platform for interaction with neighboring cells, and ultimately defining overall cell shape. Fluorescence imaging has proved to be vital in furthering our understanding of the cytoskeleton, and is now a mainstay technique used widely by cell biologists. In this review we provide an introduction to various imaging modalities used to study focal adhesions and the actin cytoskeleton, and using specific examples we highlight a number of recent studies in animal cells that have advanced our knowledge of cytoskeletal behavior.
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82
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Mitchell MJ, King MR. Physical biology in cancer. 3. The role of cell glycocalyx in vascular transport of circulating tumor cells. Am J Physiol Cell Physiol 2013; 306:C89-97. [PMID: 24133067 PMCID: PMC3919988 DOI: 10.1152/ajpcell.00285.2013] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Circulating tumor cells (CTCs) in blood are known to adhere to the luminal surface of the microvasculature via receptor-mediated adhesion, which contributes to the spread of cancer metastasis to anatomically distant organs. Such interactions between ligands on CTCs and endothelial cell-bound surface receptors are sensitive to receptor-ligand distances at the nanoscale. The sugar-rich coating expressed on the surface of CTCs and endothelial cells, known as the glycocalyx, serves as a physical structure that can control the spacing and, thus, the availability of such receptor-ligand interactions. The cancer cell glycocalyx can also regulate the ability of therapeutic ligands to bind to CTCs in the bloodstream. Here, we review the role of cell glycocalyx on the adhesion and therapeutic treatment of CTCs in the bloodstream.
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Affiliation(s)
- Michael J Mitchell
- Department of Biomedical Engineering, Cornell University, Ithaca, New York
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Schnitzbauer J, McGorty R, Huang B. 4Pi fluorescence detection and 3D particle localization with a single objective. OPTICS EXPRESS 2013; 21:19701-8. [PMID: 24105517 PMCID: PMC3796685 DOI: 10.1364/oe.21.019701] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Coherent detection through two opposing objectives (4Pi configuration) improves the precision of three-dimensional (3D) single-molecule localization substantially along the axial direction, but suffers from instrument complexity and maintenance difficulty. To address these issues, we have realized 4Pi fluorescence detection by sandwiching the sample between the objective and a mirror, and create interference of direct incidence and mirror-reflected signal at the camera with a spatial light modulator. Multifocal imaging using this single-objective mirror interference scheme offers improvement in the axial localization similar to the traditional 4Pi method. We have also devised several PSF engineering schemes to enable 3D localization with a single emitter image, offering better axial precision than normal single-objective localization methods such as astigmatic imaging.
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Affiliation(s)
- J. Schnitzbauer
- Department of Pharmaceutical Chemistry, University of California, 1700 4th St, MC 2532, San Francisco, CA 94158,
USA
| | - R. McGorty
- Department of Pharmaceutical Chemistry, University of California, 1700 4th St, MC 2532, San Francisco, CA 94158,
USA
| | - B. Huang
- Department of Pharmaceutical Chemistry, University of California, 1700 4th St, MC 2532, San Francisco, CA 94158,
USA
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84
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Chiu CL, Gratton E. Axial super resolution topography of focal adhesion by confocal microscopy. Microsc Res Tech 2013; 76:1070-8. [PMID: 23897846 DOI: 10.1002/jemt.22267] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2013] [Accepted: 07/07/2013] [Indexed: 11/07/2022]
Abstract
The protein organization within focal adhesions has been studied by state-of-the-art super resolution methods because of its thin structure, well below diffraction limit. However, to achieve high axial resolution, most of the current approaches rely on either sophisticated optics or diligent sample preparation, limiting their application. In this report we present a phasor-based method that can be applied to fluorescent samples to determine the precise axial position of proteins using a conventional confocal microscope. We demonstrate that with about 4,000 photon counts collected along a z-scan, axial localization precision close to 10 nm is achievable. We show that, with within 10 nm, the axial location of paxillin, FAK, and talin is similar at focal adhesion sites, while F-actin shows a sharp increase in height towards the cell center. We further demonstrated the live imaging capability of this method. With the advantage of simple data acquisition and no special instrument requirement, this approach could have wide dissemination and application potentials.
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Affiliation(s)
- Chi-Li Chiu
- Department of Developmental and Cell Biology, University of California, Irvine, California; Laboratory for Fluorescence Dynamics, University of California, Irvine, California
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85
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Watt FM, Huck WTS. Role of the extracellular matrix in regulating stem cell fate. Nat Rev Mol Cell Biol 2013; 14:467-73. [PMID: 23839578 DOI: 10.1038/nrm3620] [Citation(s) in RCA: 577] [Impact Index Per Article: 52.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The field of stem cells and regenerative medicine offers considerable promise as a means of delivering new treatments for a wide range of diseases. In order to maximize the effectiveness of cell-based therapies - whether stimulating expansion of endogenous cells or transplanting cells into patients - it is essential to understand the environmental (niche) signals that regulate stem cell behaviour. One of those signals is from the extracellular matrix (ECM). New technologies have offered insights into how stem cells sense signals from the ECM and how they respond to these signals at the molecular level, which ultimately regulate their fate.
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Affiliation(s)
- Fiona M Watt
- King's College London Centre for Stem Cells and Regenerative Medicine, London, UK.
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