1
|
Bernard C, Carotenuto AR, Pugno NM, Fraldi M, Deseri L. Modelling lipid rafts formation through chemo-mechanical interplay triggered by receptor-ligand binding. Biomech Model Mechanobiol 2024; 23:485-505. [PMID: 38060155 PMCID: PMC10963483 DOI: 10.1007/s10237-023-01787-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Accepted: 10/21/2023] [Indexed: 12/08/2023]
Abstract
Cell membranes, mediator of many biological mechanisms from adhesion and metabolism up to mutation and infection, are highly dynamic and heterogeneous environments exhibiting a strong coupling between biochemical events and structural re-organisation. This involves conformational changes induced, at lower scales, by lipid order transitions and by the micro-mechanical interplay of lipids with transmembrane proteins and molecular diffusion. Particular attention is focused on lipid rafts, ordered lipid microdomains rich of signalling proteins, that co-localise to enhance substance trafficking and activate different intracellular biochemical pathways. In this framework, the theoretical modelling of the dynamic clustering of lipid rafts implies a full multiphysics coupling between the kinetics of phase changes and the mechanical work performed by transmembrane proteins on lipids, involving the bilayer elasticity. This mechanism produces complex interspecific dynamics in which membrane stresses and chemical potentials do compete by determining different morphological arrangements, alteration in diffusive walkways and coalescence phenomena, with a consequent influence on both signalling potential and intracellular processes. Therefore, after identifying the leading chemo-mechanical interactions, the present work investigates from a modelling perspective the spatio-temporal evolution of raft domains to theoretically explain co-localisation and synergy between proteins' activation and raft formation, by coupling diffusive and mechanical phenomena to observe different morphological patterns and clustering of ordered lipids. This could help to gain new insights into the remodelling of cell membranes and could potentially suggest mechanically based strategies to control their selectivity, by orienting intracellular functions and mechanotransduction.
Collapse
Affiliation(s)
- Chiara Bernard
- Department of Civil, Environmental and Mechanical Engineering, University of Trento, Trento, Italy
| | - Angelo Rosario Carotenuto
- Department of Structures for Engineering and Architecture, University of Naples "Federico II", Naples, Italy
- Laboratory of Integrated Mechanics and Imaging for Testing and Simulation (LIMITS), University of Naples "Federico II", Naples, Italy
| | - Nicola Maria Pugno
- Department of Civil, Environmental and Mechanical Engineering, University of Trento, Trento, Italy
- Laboratory for Bioinspired, Bionic, Nano, Meta Materials and Mechanics, University of Trento, Trento, Italy
- School of Engineering and Materials Science, Queen Mary University of London, London, UK
| | - Massimiliano Fraldi
- Department of Structures for Engineering and Architecture, University of Naples "Federico II", Naples, Italy
- Laboratory of Integrated Mechanics and Imaging for Testing and Simulation (LIMITS), University of Naples "Federico II", Naples, Italy
- Département de Physique, LPENS, École Normale Supérieure-PSL, Paris, France
| | - Luca Deseri
- Department of Civil, Environmental and Mechanical Engineering, University of Trento, Trento, Italy.
- Department of Mechanical Engineering and Material Sciences, MEMS-SSoE, University of Pittsburgh, Pittsburgh, USA.
- Department of Civil and Environmental Engineering, Carnegie Mellon University, Pittsburgh, USA.
- Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, USA.
| |
Collapse
|
2
|
Cowan AE, Loew LM. Beyond analytic solution: Analysis of FRAP experiments by spatial simulation of the forward problem. Biophys J 2023; 122:3722-3737. [PMID: 37353932 PMCID: PMC10541496 DOI: 10.1016/j.bpj.2023.06.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 05/25/2023] [Accepted: 06/20/2023] [Indexed: 06/25/2023] Open
Abstract
Fluorescence redistribution after photobleaching is a commonly used method to understand the dynamic behavior of molecules within cells. Analytic solutions have been developed for specific, well-defined models of dynamic behavior in idealized geometries, but these solutions are inaccurate in complex geometries or when complex binding and diffusion behaviors exist. We demonstrate the use of numerical reaction-diffusion simulations using the Virtual Cell software platform to model fluorescence redistribution after photobleaching experiments. Multiple simulations employing parameter scans and varying bleaching locations and sizes can help to bracket diffusion coefficients and kinetic rate constants in complex image-based geometries. This approach is applied to problems in membrane surface diffusion as well as diffusion and binding in cytosolic volumes in complex cell geometries. In addition, we model diffusion and binding within phase-separated biomolecular condensates (liquid droplets). These are modeled as spherical low-affinity binding domains that also define a high viscosity medium for exchange of the free fluorescently labeled ligand with the external cytosol.
Collapse
Affiliation(s)
- Ann E Cowan
- Richard D. Berlin Center for Cell Analysis and Modeling, University of Connecticut School of Medicine, Farmington, Connecticut
| | - Leslie M Loew
- Richard D. Berlin Center for Cell Analysis and Modeling, University of Connecticut School of Medicine, Farmington, Connecticut.
| |
Collapse
|
3
|
Burton JC, Okalova J, Grimsey NJ. Fluorescence resonance energy transfer (FRET) spatiotemporal mapping of atypical P38 reveals an endosomal and cytosolic spatial bias. Sci Rep 2023; 13:7477. [PMID: 37156828 PMCID: PMC10167256 DOI: 10.1038/s41598-023-33953-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Accepted: 04/21/2023] [Indexed: 05/10/2023] Open
Abstract
Mitogen-activated protein kinase (MAPK) p38 is a central regulator of intracellular signaling, driving physiological and pathological pathways. With over 150 downstream targets, it is predicted that spatial positioning and the availability of cofactors and substrates determines kinase signaling specificity. The subcellular localization of p38 is highly dynamic to facilitate the selective activation of spatially restricted substrates. However, the spatial dynamics of atypical p38 inflammatory signaling are understudied. We utilized subcellular targeted fluorescence resonance energy transfer (FRET) p38 activity biosensors to map the spatial profile of kinase activity. Through comparative analysis of plasma membrane, cytosolic, nuclear, and endosomal compartments, we confirm a characteristic profile of nuclear bias for mitogen-activated kinase kinase 3/6 (MKK3/6) dependent p38 activation. Conversely, atypical p38 activation via thrombin-mediated protease-activated receptor 1 (PAR1) activity led to enhanced p38 activity at the endosome and cytosol, limiting nuclear p38 activity, a profile conserved for prostaglandin E2 activation of p38. Conversely, perturbation of receptor endocytosis led to spatiotemporal switching of thrombin signaling, reducing endosomal and cytosolic p38 activity and increasing nuclear activity. The data presented reveal the spatiotemporal dynamics of p38 activity and provide critical insight into how atypical p38 signaling drives differential signaling responses through spatial sequestration of kinase activity.
Collapse
Affiliation(s)
- Jeremy C Burton
- Department of Pharmaceutical and Biomedical Sciences, College of Pharmacy, University of Georgia, Pharmacy South Rm 414, Athens, 30602, USA
| | - Jennifer Okalova
- Department of Pharmaceutical and Biomedical Sciences, College of Pharmacy, University of Georgia, Pharmacy South Rm 414, Athens, 30602, USA
- Aflac Cancer and Blood Disorders Center, Department of Pediatrics, School of Medicine, Emory University, Atlanta, GA, 30322, USA
| | - Neil J Grimsey
- Department of Pharmaceutical and Biomedical Sciences, College of Pharmacy, University of Georgia, Pharmacy South Rm 414, Athens, 30602, USA.
| |
Collapse
|
4
|
Wåhlén E, Olsson F, Söderberg O, Lennartsson J, Heldin J. Differential impact of lipid raft depletion on platelet-derived growth factor (PDGF)-induced ERK1/2 MAP-kinase, SRC and AKT signaling. Cell Signal 2022; 96:110356. [DOI: 10.1016/j.cellsig.2022.110356] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Revised: 05/04/2022] [Accepted: 05/12/2022] [Indexed: 11/16/2022]
|
5
|
Moud AA. Fluorescence Recovery after Photobleaching in Colloidal Science: Introduction and Application. ACS Biomater Sci Eng 2022; 8:1028-1048. [PMID: 35201752 DOI: 10.1021/acsbiomaterials.1c01422] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
FRAP (fluorescence recovery after photo bleaching) is a method for determining diffusion in material science. In industrial applications such as medications, foods, Medtech, hygiene, and textiles, the diffusion process has a substantial influence on the overall qualities of goods. All these complex and heterogeneous systems have diffusion-based processes at the local level. FRAP is a fluorescence-based approach for detecting diffusion; in this method, a high-intensity laser is made for a brief period and then applied to the samples, bleaching the fluorescent chemical inside the region, which is subsequently filled up by natural diffusion. This brief Review will focus on the existing research on employing FRAP to measure colloidal system heterogeneity and explore diffusion into complicated structures. This description of FRAP will be followed by a discussion of how FRAP is intended to be used in colloidal science. When constructing the current Review, the most recent publications were reviewed for this assessment. Because of the large number of FRAP articles in colloidal research, there is currently a dearth of knowledge regarding the growth of FRAP's significance to colloidal science. Colloids make up only 2% of FRAP papers, according to ISI Web of Knowledge.
Collapse
Affiliation(s)
- Aref Abbasi Moud
- Department of Chemical and Biological Engineering, The University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
| |
Collapse
|
6
|
Bobkov D, Semenova S. Impact of lipid rafts on transient receptor potential channel activities. J Cell Physiol 2022; 237:2034-2044. [PMID: 35014032 DOI: 10.1002/jcp.30679] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Revised: 12/06/2021] [Accepted: 12/23/2021] [Indexed: 11/06/2022]
Abstract
Members of the transient receptor potential (TRP) superfamily are cation channels that are expressed in nearly every mammalian cell type and respond as cellular sensors to various environmental stimuli. Light, pressure, osmolarity, temperature, and other stimuli can induce TRP calcium conductivity and correspondingly trigger many signaling processes in cells. Disruption of TRP channel activity, as a rule, harms cellular function. Despite numerous studies, the mechanisms of TRP channel regulation are not yet sufficiently clear, in part, because TRP channels are regulated by a broad set of ligands having diverse physical and chemical features. It is now known that some TRP members are located in membrane microdomains termed lipid rafts. Moreover, interaction between specific raft-associated lipids with channels may be a key regulation mechanism. This review examines recent findings related to the roles of lipid rafts in regulation of TRP channel activity. The mechanistic events of channel interactions with the main lipid raft constituent, cholesterol, are being clarified. Better understanding of mechanisms behind such interactions would help establish the key elements of TRP channel regulation and hence allow control of cellular responses to environmental stimuli.
Collapse
Affiliation(s)
- Danila Bobkov
- Laboratory of Ionic Mechanisms of Cell Signaling, Institute of Cytology, Russian Academy of Sciences, St. Petersburg, Russia
| | - Svetlana Semenova
- Laboratory of Ionic Mechanisms of Cell Signaling, Institute of Cytology, Russian Academy of Sciences, St. Petersburg, Russia
| |
Collapse
|
7
|
Dmitriev RI, Intes X, Barroso MM. Luminescence lifetime imaging of three-dimensional biological objects. J Cell Sci 2021; 134:1-17. [PMID: 33961054 PMCID: PMC8126452 DOI: 10.1242/jcs.254763] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
A major focus of current biological studies is to fill the knowledge gaps between cell, tissue and organism scales. To this end, a wide array of contemporary optical analytical tools enable multiparameter quantitative imaging of live and fixed cells, three-dimensional (3D) systems, tissues, organs and organisms in the context of their complex spatiotemporal biological and molecular features. In particular, the modalities of luminescence lifetime imaging, comprising fluorescence lifetime imaging (FLI) and phosphorescence lifetime imaging microscopy (PLIM), in synergy with Förster resonance energy transfer (FRET) assays, provide a wealth of information. On the application side, the luminescence lifetime of endogenous molecules inside cells and tissues, overexpressed fluorescent protein fusion biosensor constructs or probes delivered externally provide molecular insights at multiple scales into protein-protein interaction networks, cellular metabolism, dynamics of molecular oxygen and hypoxia, physiologically important ions, and other physical and physiological parameters. Luminescence lifetime imaging offers a unique window into the physiological and structural environment of cells and tissues, enabling a new level of functional and molecular analysis in addition to providing 3D spatially resolved and longitudinal measurements that can range from microscopic to macroscopic scale. We provide an overview of luminescence lifetime imaging and summarize key biological applications from cells and tissues to organisms.
Collapse
Affiliation(s)
- Ruslan I. Dmitriev
- Tissue Engineering and Biomaterials Group, Department of
Human Structure and Repair, Faculty of Medicine and Health Sciences,
Ghent University, Ghent 9000,
Belgium
| | - Xavier Intes
- Department of Biomedical Engineering, Center for
Modeling, Simulation and Imaging for Medicine (CeMSIM),
Rensselaer Polytechnic Institute, Troy, NY
12180-3590, USA
| | - Margarida M. Barroso
- Department of Molecular and Cellular
Physiology, Albany Medical College,
Albany, NY 12208, USA
| |
Collapse
|
8
|
Butler PJ. Mechanobiology of dynamic enzyme systems. APL Bioeng 2020; 4:010907. [PMID: 32161834 PMCID: PMC7054122 DOI: 10.1063/1.5133645] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Accepted: 01/28/2020] [Indexed: 12/29/2022] Open
Abstract
This Perspective paper advances a hypothesis of mechanosensation by endothelial cells in which the cell is a dynamic crowded system, driven by continuous enzyme activity, that can be shifted from one non-equilibrium state to another by external force. The nature of the shift will depend on the direction, rate of change, and magnitude of the force. Whether force induces a pathophysiological or physiological change in cell biology will be determined by whether the dynamics of a cellular system can accommodate the dynamics and magnitude of the force application. The complex interplay of non-static cytoskeletal structures governs internal cellular rheology, dynamic spatial reorganization, and chemical kinetics of proteins such as integrins, and a flaccid membrane that is dynamically supported; each may constitute the necessary dynamic properties able to sense external fluid shear stress and reorganize in two and three dimensions. The resulting reorganization of enzyme systems in the cell membrane and cytoplasm may drive the cell to a new physiological state. This review focuses on endothelial cell mechanotransduction of shear stress, but may lead to new avenues of investigation of mechanobiology in general requiring new tools for interrogation of mechanobiological systems, tools that will enable the synthesis of large amounts of spatial and temporal data at the molecular, cellular, and system levels.
Collapse
Affiliation(s)
- Peter J. Butler
- Department of Biomedical Engineering The Pennsylvania State University University Park, Pennsylvania 16802, USA
| |
Collapse
|
9
|
A Tyrosine Switch on NEDD4-2 E3 Ligase Transmits GPCR Inflammatory Signaling. Cell Rep 2019; 24:3312-3323.e5. [PMID: 30232011 PMCID: PMC6226018 DOI: 10.1016/j.celrep.2018.08.061] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Revised: 07/05/2018] [Accepted: 08/21/2018] [Indexed: 02/03/2023] Open
Abstract
Ubiquitination is essential for protein degradation and signaling and pivotal to many physiological processes. Ubiquitination of a subset of G-protein-coupled receptors (GPCRs) by the E3 ligase NEDD4–2 is required for p38 activation, but how GPCRs activate NEDD4–2 to promote ubiquitinmediated signaling is not known. Here, we report that the GPCR protease-activated receptor-1 (PAR1) stimulates c-Src-mediated tyrosine phosphorylation and activation of NEDD4–2 to promote p38 signaling and endothelial barrier disruption. Using mass spectrometry, we identified a unique phosphorylated tyrosine (Y)-485 within the 2,3-linker peptide between WW domain 2 and 3 of NEDD4–2 in agonist-stimulated cells. Mutation of NEDD4–2 Y485 impaired E3 ligase activity and failed to rescue PAR1-stimulated p38 activation and endothelial barrier permeability. The purinergic P2Y1 receptor also required c-Src and NEDD4–2 tyrosine phosphorylation for p38 activation. These studies reveal a novel role for c-Src in GPCR-induced NEDD4–2 activation, which is critical for driving ubiquitin-mediated p38 inflammatory signaling. Grimsey et al. report that GPCRs stimulate activation of NEDD4–2 E3 ubiquitin ligase via c-Src to induce endothelial p38 inflammatory signaling. c-Src phosphorylates NEDD4–2 at tyrosine-485, releasing the autoinhibitory linker peptide that is critical for enhancing E3 ligase activity, and provides mechanistic insight of how GPCRs activate E3 ubiquitin ligases.
Collapse
|
10
|
Qin Q, Laub S, Shi Y, Ouyang M, Peng Q, Zhang J, Wang Y, Lu S. Fluocell for Ratiometric and High-Throughput Live-Cell Image Visualization and Quantitation. FRONTIERS IN PHYSICS 2019; 7:154. [PMID: 33163483 PMCID: PMC7646842 DOI: 10.3389/fphy.2019.00154] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Spatiotemporal regulation of molecular activities dictates cellular function and fate. Investigation of dynamic molecular activities in live cells often requires the visualization and quantitation of fluorescent ratio image sequences with subcellular resolution and in high throughput. Hence, there is a great need for convenient software tools specifically designed with these capabilities. Here we describe a well-characterized open-source software package, Fluocell, customized to visualize pixelwise ratiometric images and calculate ratio time courses with subcellular resolution and in high throughput. Fluocell also provides group statistics and kinetic analysis functions for the quantified time courses, as well as 3D structure and function visualization for ratio images. The application of Fluocell is demonstrated by the ratiometric analysis of intensity images for several single-chain Förster (or fluorescence) resonance energy transfer (FRET)-based biosensors, allowing efficient quantification of dynamic molecular activities in a heterogeneous population of single live cells. Our analysis revealed distinct activation kinetics of Fyn kinase in the cytosolic and membrane compartments, and visualized a 4D spatiotemporal distribution of epigenetic signals in mitotic cells. Therefore, Fluocell provides an integrated environment for ratiometric live-cell image visualization and analysis, which generates high-quality single-cell dynamic data and allows the quantitative machine-learning of biophysical and biochemical computational models for molecular regulations in cells and tissues.
Collapse
Affiliation(s)
- Qin Qin
- Department of Bioengineering, Institute of Engineering in Medicine, University of California, San Diego, San Diego, CA, United States
| | - Shannon Laub
- Department of Bioengineering, Institute of Engineering in Medicine, University of California, San Diego, San Diego, CA, United States
| | - Yiwen Shi
- Department of Mathematics, Center of Computational Mathematics, University of California, San Diego, San Diego, CA, United State
| | - Mingxing Ouyang
- Institute of Biomedical Engineering and Health Sciences, Changzhou University, Changzhou, China
| | - Qin Peng
- Department of Bioengineering, Institute of Engineering in Medicine, University of California, San Diego, San Diego, CA, United States
| | - Jin Zhang
- Department of Pharmacology, University of California, San Diego, San Diego, CA, United States
| | - Yingxiao Wang
- Department of Bioengineering, Institute of Engineering in Medicine, University of California, San Diego, San Diego, CA, United States
| | - Shaoying Lu
- Department of Bioengineering, Institute of Engineering in Medicine, University of California, San Diego, San Diego, CA, United States
- Department of Mathematics, Center of Computational Mathematics, University of California, San Diego, San Diego, CA, United State
| |
Collapse
|
11
|
Wan R, Wu J, Ouyang M, Lei L, Wei J, Peng Q, Harrison R, Wu Y, Cheng B, Li K, Zhu C, Tang L, Wang Y, Lu S. Biophysical basis underlying dynamic Lck activation visualized by ZapLck FRET biosensor. SCIENCE ADVANCES 2019; 5:eaau2001. [PMID: 31223643 PMCID: PMC6584686 DOI: 10.1126/sciadv.aau2001] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Accepted: 05/15/2019] [Indexed: 05/25/2023]
Abstract
Lck plays crucial roles in TCR signaling. We developed a new and sensitive FRET biosensor (ZapLck) to visualize Lck kinase activity with high spatiotemporal resolutions in live cells. ZapLck revealed that 62% of Lck signal was preactivated in T-cells. In Lck-deficient JCam T-cells, Lck preactivation was abolished, which can be restored to 51% by reconstitution with wild-type Lck (LckWT) but not a putatively inactive mutant LckY394F. LckWT also showed a stronger basal Lck-Lck interaction and a slower diffusion rate than LckY394F. Interestingly, aggregation of TCR receptors by antibodies in JCam cells led to a strong activation of reconstituted LckY394F similar to LckWT. Both activated LckY394F and LckWT diffused more slowly and displayed increased Lck-Lck interaction at a similar level. Therefore, these results suggest that a phosphorylatable Y394 is necessary for the basal-level interaction and preactivation of LckWT, while antibody-induced TCR aggregation can trigger the full activation of LckY394F.
Collapse
Affiliation(s)
- Rongxue Wan
- Key Laboratory of Biorheological Science and Technology, Ministry of Education, College of Bioengineering, Chongqing University, Chongqing 400044, China
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093, USA
- Institute of Engineering in Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Jenny Wu
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093, USA
| | - Mingxing Ouyang
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093, USA
| | - Lei Lei
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093, USA
| | - Jiaming Wei
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093, USA
| | - Qin Peng
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093, USA
- Institute of Engineering in Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Reed Harrison
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093, USA
- Institute of Engineering in Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Yiqian Wu
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093, USA
- Institute of Engineering in Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Binbin Cheng
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093, USA
| | - Kaitao Li
- Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Cheng Zhu
- Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Liling Tang
- Key Laboratory of Biorheological Science and Technology, Ministry of Education, College of Bioengineering, Chongqing University, Chongqing 400044, China
| | - Yingxiao Wang
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093, USA
- Institute of Engineering in Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Shaoying Lu
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093, USA
- Institute of Engineering in Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| |
Collapse
|
12
|
Ouyang M, Wan R, Qin Q, Peng Q, Wang P, Wu J, Allen M, Shi Y, Laub S, Deng L, Lu S, Wang Y. Sensitive FRET Biosensor Reveals Fyn Kinase Regulation by Submembrane Localization. ACS Sens 2019; 4:76-86. [PMID: 30588803 DOI: 10.1021/acssensors.8b00896] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Fyn kinase plays crucial roles in hematology and T cell signaling; however, there are currently limited tools to visualize the dynamic Fyn activity in live cells. Here we developed and characterized a highly sensitive Fyn biosensor based on fluorescence resonance energy transfer (FRET) to monitor Fyn kinase activity in live cells. Our results show that Fyn kinase activity can be induced in both mouse embryonic fibroblasts (MEFs) and T cells by ligand engagement. Two different motifs were further introduced to target the biosensor at the cellular membrane microdomains in MEFs, revealing that the Fyn-tagged biosensor had 70% greater response to growth factor stimulation than the Lyn-tagged version. This suggests that the plasma membrane microdomains can be categorized into different functional subdomains. Further experiments show that while the membrane accessibility is necessary for Fyn activation, the localization of Fyn outside of its microdomains causes its hyperactivity, indicating that membrane microdomains provide a suppressive microenvironment for Fyn regulation in MEFs. Interestingly, a relatively high Fyn activity can be observed at perinuclear regions, further supporting the notion that the membrane microenvironment has a significant impact on the local molecular functions. Our work hence highlights a novel Fyn FRET biosensor for live cell imaging and its application in revealing an intricate submembrane regulation of Fyn in live MEFs.
Collapse
Affiliation(s)
- Mingxing Ouyang
- Department of Bioengineering, University of California at San Diego, La Jolla, California 92093, United States
- Institute of Biomedical Engineering and Health Sciences, Changzhou University, Changzhou, Jiangsu Province 213164, China
| | - Rongxue Wan
- Department of Bioengineering, University of California at San Diego, La Jolla, California 92093, United States
- Key Laboratory of Biorheological Science and Technology, Ministry of Education, College of Bioengineering, Chongqing University, Chongqing 400044, China
| | - Qin Qin
- Department of Bioengineering, University of California at San Diego, La Jolla, California 92093, United States
| | - Qin Peng
- Department of Bioengineering, University of California at San Diego, La Jolla, California 92093, United States
| | - Pengzhi Wang
- Department of Bioengineering, University of California at San Diego, La Jolla, California 92093, United States
| | - Jenny Wu
- Department of Bioengineering, University of California at San Diego, La Jolla, California 92093, United States
| | - Molly Allen
- Department of Bioengineering, University of California at San Diego, La Jolla, California 92093, United States
| | - Yiwen Shi
- Department of Bioengineering, University of California at San Diego, La Jolla, California 92093, United States
| | - Shannon Laub
- Department of Bioengineering, University of California at San Diego, La Jolla, California 92093, United States
| | - Linhong Deng
- Institute of Biomedical Engineering and Health Sciences, Changzhou University, Changzhou, Jiangsu Province 213164, China
| | - Shaoying Lu
- Department of Bioengineering, University of California at San Diego, La Jolla, California 92093, United States
| | - Yingxiao Wang
- Department of Bioengineering, University of California at San Diego, La Jolla, California 92093, United States
| |
Collapse
|
13
|
Greenwald EC, Mehta S, Zhang J. Genetically Encoded Fluorescent Biosensors Illuminate the Spatiotemporal Regulation of Signaling Networks. Chem Rev 2018; 118:11707-11794. [PMID: 30550275 PMCID: PMC7462118 DOI: 10.1021/acs.chemrev.8b00333] [Citation(s) in RCA: 316] [Impact Index Per Article: 52.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Cellular signaling networks are the foundation which determines the fate and function of cells as they respond to various cues and stimuli. The discovery of fluorescent proteins over 25 years ago enabled the development of a diverse array of genetically encodable fluorescent biosensors that are capable of measuring the spatiotemporal dynamics of signal transduction pathways in live cells. In an effort to encapsulate the breadth over which fluorescent biosensors have expanded, we endeavored to assemble a comprehensive list of published engineered biosensors, and we discuss many of the molecular designs utilized in their development. Then, we review how the high temporal and spatial resolution afforded by fluorescent biosensors has aided our understanding of the spatiotemporal regulation of signaling networks at the cellular and subcellular level. Finally, we highlight some emerging areas of research in both biosensor design and applications that are on the forefront of biosensor development.
Collapse
Affiliation(s)
- Eric C Greenwald
- University of California , San Diego, 9500 Gilman Drive, BRFII , La Jolla , CA 92093-0702 , United States
| | - Sohum Mehta
- University of California , San Diego, 9500 Gilman Drive, BRFII , La Jolla , CA 92093-0702 , United States
| | - Jin Zhang
- University of California , San Diego, 9500 Gilman Drive, BRFII , La Jolla , CA 92093-0702 , United States
| |
Collapse
|
14
|
Sehgal P, Kong X, Wu J, Sunyer R, Trepat X, Leckband D. Epidermal growth factor receptor and integrins control force-dependent vinculin recruitment to E-cadherin junctions. J Cell Sci 2018; 131:jcs206656. [PMID: 29487179 PMCID: PMC5897709 DOI: 10.1242/jcs.206656] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Accepted: 02/07/2018] [Indexed: 12/30/2022] Open
Abstract
This study reports novel findings that link E-cadherin (also known as CDH1)-mediated force-transduction signaling to vinculin targeting to intercellular junctions via epidermal growth factor receptor (EGFR) and integrins. These results build on previous findings that demonstrated that mechanically perturbed E-cadherin receptors activate phosphoinositide 3-kinase and downstream integrins in an EGFR-dependent manner. Results of this study show that this EGFR-mediated kinase cascade controls the force-dependent recruitment of vinculin to stressed E-cadherin complexes - a key early signature of cadherin-based mechanotransduction. Vinculin targeting requires its phosphorylation at tyrosine 822 by Abl family kinases (hereafter Abl), but the origin of force-dependent Abl activation had not been identified. We now present evidence that integrin activation, which is downstream of EGFR signaling, controls Abl activation, thus linking E-cadherin to Abl through a mechanosensitive signaling network. These findings place EGFR and integrins at the center of a positive-feedback loop, through which force-activated E-cadherin signals regulate vinculin recruitment to cadherin complexes in response to increased intercellular tension.This article has an associated First Person interview with the first author of the paper.
Collapse
Affiliation(s)
- Poonam Sehgal
- Department of Biochemistry, University of Illinois, Urbana-Champaign, IL 61802, USA
| | - Xinyu Kong
- Department of Biochemistry, University of Illinois, Urbana-Champaign, IL 61802, USA
| | - Jun Wu
- Department of Chemical and Biomolecular Engineering, University of Illinois, Urbana-Champaign, IL 61802, USA
| | - Raimon Sunyer
- Institute for Bioengineering of Catalonia, Barcelona, Spain 08028
- Centro de Investigación Biomédica en Red en Bioingeniería, Biomateriales y Nanomedicina, Barcelona, Spain 08028
| | - Xavier Trepat
- Institute for Bioengineering of Catalonia, Barcelona, Spain 08028
- Centro de Investigación Biomédica en Red en Bioingeniería, Biomateriales y Nanomedicina, Barcelona, Spain 08028
- Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Spain 08028
| | - Deborah Leckband
- Department of Biochemistry, University of Illinois, Urbana-Champaign, IL 61802, USA
- Department of Chemical and Biomolecular Engineering, University of Illinois, Urbana-Champaign, IL 61802, USA
- Department of Chemistry, University of Illinois, Urbana-Champaign, IL 61802, USA
| |
Collapse
|
15
|
Limsakul P, Peng Q, Wu Y, Allen ME, Liang J, Remacle AG, Lopez T, Ge X, Kay BK, Zhao H, Strongin AY, Yang XL, Lu S, Wang Y. Directed Evolution to Engineer Monobody for FRET Biosensor Assembly and Imaging at Live-Cell Surface. Cell Chem Biol 2018; 25:370-379.e4. [PMID: 29396288 DOI: 10.1016/j.chembiol.2018.01.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Revised: 06/01/2017] [Accepted: 12/29/2017] [Indexed: 12/14/2022]
Abstract
Monitoring enzymatic activities at the cell surface is challenging due to the poor efficiency of transport and membrane integration of fluorescence resonance energy transfer (FRET)-based biosensors. Therefore, we developed a hybrid biosensor with separate donor and acceptor that assemble in situ. The directed evolution and sequence-function analysis technologies were integrated to engineer a monobody variant (PEbody) that binds to R-phycoerythrin (R-PE) dye. PEbody was used for visualizing the dynamic formation/separation of intercellular junctions. We further fused PEbody with the enhanced CFP and an enzyme-specific peptide at the extracellular surface to create a hybrid FRET biosensor upon R-PE capture for monitoring membrane-type-1 matrix metalloproteinase (MT1-MMP) activities. This biosensor revealed asymmetric distribution of MT1-MMP activities, which were high and low at loose and stable cell-cell contacts, respectively. Therefore, directed evolution and rational design are promising tools to engineer molecular binders and hybrid FRET biosensors for monitoring molecular regulations at the surface of living cells.
Collapse
Affiliation(s)
- Praopim Limsakul
- Department of Bioengineering, Institute of Engineering in Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Qin Peng
- Department of Bioengineering, Institute of Engineering in Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Yiqian Wu
- Department of Bioengineering, Institute of Engineering in Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Molly E Allen
- Department of Bioengineering, Institute of Engineering in Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Jing Liang
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Albert G Remacle
- Sanford-Burnham-Prebys Medical Discovery Institute, La Jolla, CA 92037, USA
| | - Tyler Lopez
- Department of Chemical and Environmental Engineering, University of California, Riverside, Riverside, CA, USA
| | - Xin Ge
- Department of Chemical and Environmental Engineering, University of California, Riverside, Riverside, CA, USA
| | - Brian K Kay
- Department of Biological Sciences, University of Illinois Chicago, Chicago, IL 60607, USA
| | - Huimin Zhao
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Alex Y Strongin
- Sanford-Burnham-Prebys Medical Discovery Institute, La Jolla, CA 92037, USA
| | - Xiang-Lei Yang
- Departments of Chemical Physiology and Cell and Molecular Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Shaoying Lu
- Department of Bioengineering, Institute of Engineering in Medicine, University of California, San Diego, La Jolla, CA 92093, USA.
| | - Yingxiao Wang
- Department of Bioengineering, Institute of Engineering in Medicine, University of California, San Diego, La Jolla, CA 92093, USA.
| |
Collapse
|
16
|
β 1-Integrin-Mediated Adhesion Is Lipid-Bilayer Dependent. Biophys J 2017; 113:1080-1092. [PMID: 28877491 DOI: 10.1016/j.bpj.2017.07.010] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Revised: 06/19/2017] [Accepted: 07/13/2017] [Indexed: 11/21/2022] Open
Abstract
Integrin-mediated adhesion is a central feature of cellular adhesion, locomotion, and endothelial cell mechanobiology. Although integrins are known to be transmembrane proteins, little is known about the role of membrane biophysics and dynamics in integrin adhesion. We treated human aortic endothelial cells with exogenous amphiphiles, shown previously in model membranes, and computationally, to affect bilayer thickness and lipid phase separation, and subsequently measured single-integrin-molecule adhesion kinetics using an optical trap, and diffusion using fluorescence correlation spectroscopy. Benzyl alcohol (BA) partitions to liquid-disordered (Ld) domains, thins them, and causes the greatest increase in hydrophobic mismatch between liquid-ordered (Lo) and Ld domains among the three amphiphiles, leading to domain separation. In human aortic endothelial cells, BA increased β1-integrin-Arg-Gly-Asp-peptide affinity by 18% with a transition from single to double valency, consistent with a doubling of the molecular brightness of mCherry-tagged β1-integrins measured using fluorescence correlation spectroscopy. Accordingly, BA caused an increase in the size of focal-adhesion-kinase/paxillin-positive peripheral adhesions and reduced migration speeds as measured using wound-healing assays. Vitamin E, which thickens Lo domains and disperses them by lowering edge energy on domain boundaries, left integrin affinity unchanged but reduced binding probability, leading to smaller focal adhesions and equivalent migration speed relative to untreated cells. Vitamin E reversed the BA-induced decrease in migration speed. Triton X-100 also thickens Lo domains, but partitions to both lipid phases and left unchanged binding kinetics, focal adhesion sizes, and migration speed. These results demonstrate that only the amphiphile that thinned Ld lipid domains increased β1-integrin-Arg-Gly-Asp-peptide affinity and valency, thus implicating Ld domains in modulation of integrin adhesion, nascent adhesion formation, and cell migration.
Collapse
|
17
|
Rajamanickam GD, Kastelic JP, Thundathil JC. Na/K-ATPase regulates bovine sperm capacitation through raft- and non-raft-mediated signaling mechanisms. Mol Reprod Dev 2017; 84:1168-1182. [PMID: 28833817 DOI: 10.1002/mrd.22879] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2016] [Accepted: 08/09/2017] [Indexed: 11/06/2022]
Abstract
Highly dynamic lipid microdomains (rafts) in the sperm plasma membrane contain several signaling proteins that regulate sperm capacitation. Na/K-ATPase isoforms (testis-specific isoform ATP1A4 and ubiquitous isoform ATP1A1) are abundant in bovine sperm plasma membrane. We previously reported that incubation of bovine sperm with ouabain, a specific Na/K-ATPase ligand, induced tyrosine phosphorylation of several sperm proteins during capacitation. The objective of this study was to investigate the roles of lipid rafts and non-rafts in Na/K-ATPase enzyme activity and signaling during bovine sperm capacitation. Content of ATP1A4 and, to a lesser extent, ATP1A1 was increased in raft and non-raft fractions of capacitated sperm, although non-raft enzyme activities of both isoforms were higher than the corresponding activities in rafts from capacitated sperm. Yet, ATP1A4 was the predominant isoform responsible for total Na/K-ATPase activity in both rafts and non-rafts. A comparative increase in phosphorylation of signaling molecules was observed in both raft (CAV1) and non-raft (EGFR and ERK1/2) membrane fractions during capacitation. Although SRC was phosphorylated in both membrane fractions, the non-raft fraction possessed more of this activated form. We also inferred, by immunoprecipitation, that ATP1A4 interacted with CAV1 and EGFR in the raft fraction, whereas interactions of ATP1A4 with SRC, EGFR, and ERK1/2 occurred in the non-raft fraction of ouabain-capacitated sperm; conversely, ATP1A1 interacted only with CAV1 in both fractions of uncapacitated and capacitated sperm. In conclusion, both raft and non-raft cohorts of Na/K-ATPase isoforms contributed to phosphorylation of signaling molecules during bovine sperm capacitation.
Collapse
Affiliation(s)
- Gayathri D Rajamanickam
- Faculty of Veterinary Medicine, Department of Production Animal Health, University of Calgary, Calgary, Alberta, Canada
| | - John P Kastelic
- Faculty of Veterinary Medicine, Department of Production Animal Health, University of Calgary, Calgary, Alberta, Canada
| | - Jacob C Thundathil
- Faculty of Veterinary Medicine, Department of Production Animal Health, University of Calgary, Calgary, Alberta, Canada
| |
Collapse
|
18
|
Abstract
Early Ca2+ signaling is characterized by occurrence of Ca2+ microdomains formed by opening of single or clusters of Ca2+ channels, thereby initiating first signaling and subsequently activating global Ca2+ signaling mechanisms. However, only few data are available focusing on the first seconds and minutes of Ca2+ microdomain formation and related signaling pathways in activated T-lymphocytes. In this review, we condense current knowledge on Ca2+ microdomain formation in T-lymphocytes and early Ca2+ signaling, function of Ca2+ microdomains, and microdomain organization. Interestingly, considering the first seconds of T cell activation, a triphasic Ca2+ signal is becoming apparent: (i) initial Ca2+ microdomains occurring in the first second of T cell activation, (ii) amplification of Ca2+ microdomains by recruitment of further channels in the next 5-10 s, and (iii) a transition to global Ca2+ increase. Apparently, the second messenger nicotinic acid adenine dinucleotide phosphate is the first second messenger involved in initiation of Ca2+ microdomains. Ryanodine receptors type 1 act as initial Ca2+ release channels in CD4+ T-lymphocytes. Regarding the temporal correlation of Ca2+ microdomains with other molecular events of T cell activation, T cell receptor-dependent microdomain organization of signaling molecules Grb2 and Src homology [SH2] domain-containing leukocyte protein of 65 kDa was observed within the first 20 s. In addition, fast cytoskeletal changes are initiated. Furthermore, the involvement of additional Ca2+ channels and organelles, such as the Ca2+ buffering mitochondria, is discussed. Future research developments will comprise analysis of the causal relation between these temporally coordinated signaling events. Taken together, high-resolution Ca2+ imaging techniques applied to T cell activation in the past years paved the way to detailed molecular understanding of initial Ca2+ signaling mechanisms in non-excitable cells.
Collapse
Affiliation(s)
- Insa M A Wolf
- The Calcium Signalling Group, Department of Biochemistry and Molecular Cell Biology, University Medical Centre Hamburg-Eppendorf, Hamburg, Germany
| | - Andreas H Guse
- The Calcium Signalling Group, Department of Biochemistry and Molecular Cell Biology, University Medical Centre Hamburg-Eppendorf, Hamburg, Germany
| |
Collapse
|
19
|
Effect of probe diffusion on the SOFI imaging accuracy. Sci Rep 2017; 7:44665. [PMID: 28333166 PMCID: PMC5363082 DOI: 10.1038/srep44665] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Accepted: 02/13/2017] [Indexed: 01/19/2023] Open
Abstract
Live-cell super-resolution fluorescence imaging is becoming commonplace for exploring biological systems, though sample dynamics can affect the imaging quality. In this work we evaluate the effect of probe diffusion on super-resolution optical fluctuation imaging (SOFI), using a theoretical model and numerical simulations based on the imaging of live cells labelled with photochromic fluorescent proteins. We find that, over a range of physiological conditions, fluorophore diffusion results in a change in the amplitude of the SOFI signal. The magnitude of this change is approximately proportional to the on-time ratio of the fluorophores. However, for photochromic fluorescent proteins this effect is unlikely to present a significant distortion in practical experiments in biological systems. Due to this lack of distortions, probe diffusion strongly enhances the SOFI imaging by avoiding spatial undersampling caused by the limited labeling density.
Collapse
|
20
|
Wu Y, Zhang K, Seong J, Fan J, Chien S, Wang Y, Lu S. In-situ coupling between kinase activities and protein dynamics within single focal adhesions. Sci Rep 2016; 6:29377. [PMID: 27383747 PMCID: PMC4935953 DOI: 10.1038/srep29377] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2016] [Accepted: 06/15/2016] [Indexed: 11/30/2022] Open
Abstract
The dynamic activation of oncogenic kinases and regulation of focal adhesions (FAs) are crucial molecular events modulating cell adhesion in cancer metastasis. However, it remains unclear how these events are temporally coordinated at single FA sites. Therefore, we targeted fluorescence resonance energy transfer (FRET)-based biosensors toward subcellular FAs to report local molecular events during cancer cell adhesion. Employing single FA tracking and cross-correlation analysis, we quantified the dynamic coupling characteristics between biochemical kinase activities and structural FA within single FAs. We show that kinase activations and FA assembly are strongly and sequentially correlated, with the concurrent FA assembly and Src activation leading focal adhesion kinase (FAK) activation by 42.6 ± 12.6 sec. Strikingly, the temporal coupling between kinase activation and individual FA assembly reflects the fate of FAs at later stages. The FAs with a tight coupling tend to grow and mature, while the less coupled FAs likely disassemble. During FA disassembly, however, kinase activations lead the disassembly, with FAK being activated earlier than Src. Therefore, by integrating subcellularly targeted FRET biosensors and computational analysis, our study reveals intricate interplays between Src and FAK in regulating the dynamic life of single FAs in cancer cells.
Collapse
Affiliation(s)
- Yiqian Wu
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093, USA
| | - Kaiwen Zhang
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093, USA
| | - Jihye Seong
- Center for Neuro-Medicine, Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, South Korea
| | - Jason Fan
- Institute of Engineering in Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Shu Chien
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093, USA.,Institute of Engineering in Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Yingxiao Wang
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093, USA.,Institute of Engineering in Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Shaoying Lu
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093, USA.,Institute of Engineering in Medicine, University of California, San Diego, La Jolla, CA 92093, USA.,Center of Computational Mathematics, University of California, San Diego, La Jolla, CA 92093, USA
| |
Collapse
|
21
|
Li K, Xiang X, Sun J, He HT, Wu J, Wang Y, Zhu C. Imaging Spatiotemporal Activities of ZAP-70 in Live T Cells Using a FRET-Based Biosensor. Ann Biomed Eng 2016; 44:3510-3521. [PMID: 27384937 DOI: 10.1007/s10439-016-1683-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Accepted: 06/21/2016] [Indexed: 01/20/2023]
Abstract
The zeta-chain-associated protein kinase 70 kDa (ZAP-70), a member of the spleen tyrosine kinase (Syk) family, plays an essential role in early T cell receptor (TCR) signaling. Defects in ZAP-70 lead to impaired thymocyte development and peripheral T cell activation. To better understand its activation dynamics and regulation, we visualized ZAP-70 activities in single live T cells with a Förster resonance energy transfer (FRET)-based biosensor, which was designed for probing kinase activities of the Syk family. We observed in Jurkat E6.1 T cells rapid and specific FRET changes following anti-CD3 stimulation and subsequent piceatannol inhibition. The initiation of ZAP-70 activation was prompt (within 10 s) and correlates with the accompanied intracellular calcium elevation, as revealed by simultaneous imaging of the biosensor and calcium. Different from the previously reported ZAP-70 activation in the immunological synapse and the opposite pole (anti-synapse), we have observed rapid and sustained ZAP-70 activation only at the synapse with superantigen-pulsed Raji B cells. Furthermore, ZAP-70 signaling was impaired by cholesterol depletion, further supporting the importance of membrane organization in TCR signaling. Together our results provide a direct characterization of the spatiotemporal features of ZAP-70 activity in real time at subcellular levels.
Collapse
Affiliation(s)
- Kaitao Li
- Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA, USA
| | - Xue Xiang
- Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA, USA.,School of Life Sciences, SUN YAT-SEN University, Guangzhou, China.,UnionPay Smart Co., Ltd, Shanghai, China
| | - Jie Sun
- Department of Bioengineering and Beckman Institute for Advanced Science and Technology, University of Illinois, Urbana-Champaign, Urbana, IL, USA.,Center for Cell Engineering, Memorial Sloan Kettering Cancer Center, New York, USA
| | - Hai-Tao He
- Centre d'Immunologie de Marseille-Luminy, Aix Marseille Université UM2, Inserm, U1104, CNRS UMR7280, 13288, Marseille, France
| | - Jianhua Wu
- School of Life Sciences, SUN YAT-SEN University, Guangzhou, China.,School of Bioscience, South China University of Technology, Guangzhou, China
| | - Yingxiao Wang
- Department of Bioengineering and Beckman Institute for Advanced Science and Technology, University of Illinois, Urbana-Champaign, Urbana, IL, USA.,Department of Bioengineering, University of California, San Diego, La Jolla, CA, USA
| | - Cheng Zhu
- Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA, USA.
| |
Collapse
|
22
|
White KM, Sabatino JA, He M, Davis N, Tang N, Bearer CF. Toluene disruption of the functions of L1 cell adhesion molecule at concentrations associated with occupational exposures. Pediatr Res 2016; 80:145-50. [PMID: 27027721 PMCID: PMC4929035 DOI: 10.1038/pr.2016.40] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/05/2015] [Accepted: 01/05/2016] [Indexed: 02/01/2023]
Abstract
BACKGROUND Prenatal toluene exposure can cause neurodevelopmental disabilities similar to fetal alcohol syndrome. Both share neuroanatomic pathologies similar to children with mutations in L1 cell adhesion molecule (L1). L1 mediates neurite outgrowth (NOG) via signaling through ERK1/2, which require trafficking of L1 through lipid rafts. Our objective is to determine if toluene inhibits L1-mediated NOG and toluene inhibits L1 signaling at concentrations achieved during occupational exposure. METHODS Concentrations of toluene reflective of blood concentrations achieved in solvent abusers and occupational settings are used. Cerebellar granule neurons (CGN) harvested from postnatal day 6 rat pups are plated on coverslips coated with poly-L-lysine (PLL) alone or PLL followed by laminin. L1 is added to the media of CGN plated on PLL alone. Toluene is added 2 h after plating. Cells are fixed at 24 h and neurite length is measured. ERK1/2 activation by L1 in CGN is analyzed by immunoblot. RESULTS Toluene significantly reduced mean neurite length of CGN exposed to L1 but not laminin. Toluene significantly reduced L1-mediated ERK1/2 phosphorylation. CONCLUSION Results suggest that toluene inhibits L1-lipid raft interactions at occupationally relevant concentrations and may lead to a fetal solvent spectrum disorder similar to fetal alcohol spectrum disorder.
Collapse
Affiliation(s)
- Kimberly M.R. White
- Pediatrics, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Julia A. Sabatino
- Pediatrics, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Min He
- Pediatrics, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Natalie Davis
- Pediatrics, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Ningfeng Tang
- Pediatrics, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Cynthia F Bearer
- Pediatrics, University of Maryland School of Medicine, Baltimore, MD, United States
| |
Collapse
|
23
|
Leng AW, Li D, Chen L, Xia H, Tang Q, Chen B, Gong Q, Gao F, Bi F. Novel Bioluminescent Activatable Reporter for Src Tyrosine Kinase Activity in Living Mice. Theranostics 2016; 6:594-609. [PMID: 26941850 PMCID: PMC4775867 DOI: 10.7150/thno.14306] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Accepted: 01/27/2016] [Indexed: 02/05/2023] Open
Abstract
Aberrant activation of the Src kinase is implicated in the development of a variety of human malignancies. However, it is almost impossible to monitor Src activity in an in vivo setting with current biochemical techniques. To facilitate the noninvasive investigation of the activity of Src kinase both in vitro and in vivo, we developed a genetically engineered, activatable bioluminescent reporter using split-luciferase complementation. The bioluminescence of this reporter can be used as a surrogate for Src activity in real time. This hybrid luciferase reporter was constructed by sandwiching a Src-dependent conformationally responsive unit (SH2 domain-Srcpep) between the split luciferase fragments. The complementation bioluminescence of this reporter was dependent on the Src activity status. In our study, Src kinase activity in cultured cells and tumor xenografts was monitored quantitatively and dynamically in response to clinical small-molecular kinase inhibitors, dasatinib and saracatinib. This system was also applied for high-throughput screening of Src inhibitors against a kinase inhibitor library in living cells. These results provide unique insights into drug development and pharmacokinetics/phoarmocodynamics of therapeutic drugs targeting Src signaling pathway enabling the optimization of drug administration schedules for maximum benefit. Using both Firefly and Renilla luciferase imaging, we have successfully monitored Src tyrosine kinase activity and Akt serine/threonine kinase activity concurrently in one tumor xenograft. This dual luciferase reporter imaging system will be helpful in exploring the complex signaling networks in vivo. The strategies reported here can also be extended to study and image other important kinases and the cross-talks among them.
Collapse
|
24
|
Chung EY, Ochs CJ, Wang Y, Lei L, Qin Q, Smith AM, Strongin AY, Kamm R, Qi YX, Lu S, Wang Y. Activatable and Cell-Penetrable Multiplex FRET Nanosensor for Profiling MT1-MMP Activity in Single Cancer Cells. NANO LETTERS 2015; 15:5025-5032. [PMID: 26203778 PMCID: PMC4675668 DOI: 10.1021/acs.nanolett.5b01047] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
We developed a quantum-dot-based fluorescence resonance energy transfer (QD-FRET) nanosensor to visualize the activity of matrix metalloproteinase (MT1-MMP) at cell membrane. A bended peptide with multiple motifs was engineered to position the FRET pair at a close proximity to allow energy transfer, which can be cleaved by active MT1-MMP to result in FRET changes and the exposure of cell penetrating sequence. Via FRET and penetrated QD signals, the nanosensor can profile cancer cells.
Collapse
Affiliation(s)
- Eddie Y. Chung
- Department of Bioengineering & Institute of Engineering in Medicine, University of California—San Diego, La Jolla, California 92093, United States
| | - Christopher J. Ochs
- Singapore-MIT Alliance for Research and Technology, BioSystems and Micromechanics, Singapore 138602
| | - Yi Wang
- Department of Bioengineering, University of Illinois at Urbana–Champaign, Champaign, Illinois 61801, United States
| | - Lei Lei
- Department of Bioengineering & Institute of Engineering in Medicine, University of California—San Diego, La Jolla, California 92093, United States
- Department of Bioengineering, University of Illinois at Urbana–Champaign, Champaign, Illinois 61801, United States
| | - Qin Qin
- Department of Bioengineering & Institute of Engineering in Medicine, University of California—San Diego, La Jolla, California 92093, United States
| | - Andrew M. Smith
- Department of Bioengineering, University of Illinois at Urbana–Champaign, Champaign, Illinois 61801, United States
| | - Alex Y. Strongin
- Sanford Burnham Medical Research Institute, La Jolla, California 92037, United States
| | - Roger Kamm
- Singapore-MIT Alliance for Research and Technology, BioSystems and Micromechanics, Singapore 138602
| | - Ying-Xin Qi
- Institute of Mechanobiology and Medical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Shaoying Lu
- Department of Bioengineering & Institute of Engineering in Medicine, University of California—San Diego, La Jolla, California 92093, United States
- Department of Bioengineering, University of Illinois at Urbana–Champaign, Champaign, Illinois 61801, United States
| | - Yingxiao Wang
- Department of Bioengineering & Institute of Engineering in Medicine, University of California—San Diego, La Jolla, California 92093, United States
- Department of Bioengineering, University of Illinois at Urbana–Champaign, Champaign, Illinois 61801, United States
| |
Collapse
|
25
|
Subcellular and Dynamic Coordination between Src Activity and Cell Protrusion in Microenvironment. Sci Rep 2015; 5:12963. [PMID: 26261043 PMCID: PMC4531316 DOI: 10.1038/srep12963] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Accepted: 06/11/2015] [Indexed: 01/10/2023] Open
Abstract
Migration of endothelial cells is essential for wound healing and angiogenesis. Src kinase activity plays important roles at the protrusions of migrating endothelial cells. However, the spatiotemporal coordination between Src kinase activity and the protrusion of cell edge remains unclear. Therefore, we investigate these coordinated molecular events at the initiation of cell migration, by integrating microfabrication, fluorescence resonance energy transfer (FRET)-based biosensors, and automated computational image analysis. We demonstrate that the physical release of restrictive micropattern triggered a significant decrease of Src activity at the protrusive edge of endothelial cells. Computational cross-correlation analysis reveals that the decrease of Src activity occurred earlier in time, and was well-coordinated with the protrusion of cell edge in polarized cells, but not in non-polarized cells. These results suggest that the spatiotemporal control of Src kinase activity is well-coordinated with cell polarization and protrusion in endothelial cells upon the release of physical constraint, as that experienced by endothelial cells sprouting from stiff tumor micro-environment during angiogenesis. Therefore, our integrative approach enabled the discovery of a new model where Src is de-activated in coordination with membrane protrusion, providing important insights into the regulation of endothelial migration and angiogenesis.
Collapse
|
26
|
Blumenthal D, Goldstien L, Edidin M, Gheber LA. Universal Approach to FRAP Analysis of Arbitrary Bleaching Patterns. Sci Rep 2015; 5:11655. [PMID: 26108191 PMCID: PMC4479983 DOI: 10.1038/srep11655] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2014] [Accepted: 05/07/2015] [Indexed: 11/23/2022] Open
Abstract
The original approach to calculating diffusion coefficients of a fluorescent probe from Fluorescence Recovery After Photobleaching (FRAP) measurements assumes bleaching with a circular laser beam of a Gaussian intensity profile. This method was used without imaging the bleached cell. An empirical equation for calculating diffusion coefficients from a rectangular bleaching geometry, created in a confocal image, was later published, however a single method allowing the calculation of diffusion coefficients for arbitrary geometry does not exist. Our simulation approach allows computation of diffusion coefficients regardless of bleaching geometry used in the FRAP experiment. It accepts a multiple-frame TIFF file, representing the experiment as input, and simulates the (pure) diffusion of the fluorescent probes (2D random walk) starting with the first post-bleach frame of the actual data. It then fits the simulated data to the real data and extracts the diffusion coefficient. We validate our approach using a well characterized diffusing molecule (DiIC18) against well-established analytical procedures. We show that the algorithm is able to calculate the absolute value of diffusion coefficients for arbitrary bleaching geometries, including exaggeratedly large ones. It is provided freely as an ImageJ plugin, and should facilitate quantitative FRAP measurements for users equipped with standard fluorescence microscopy setups.
Collapse
Affiliation(s)
- Daniel Blumenthal
- The Avram and Stella Goldstein-Goren Department of Biotechnology Engineering, Ben Gurion University of the Negev, Beer-Sheva, ISRAEL
| | - Leo Goldstien
- The Avram and Stella Goldstein-Goren Department of Biotechnology Engineering, Ben Gurion University of the Negev, Beer-Sheva, ISRAEL
| | - Michael Edidin
- Department of Biology, Johns Hopkins University, Baltimore, MD, USA
| | - Levi A. Gheber
- The Avram and Stella Goldstein-Goren Department of Biotechnology Engineering, Ben Gurion University of the Negev, Beer-Sheva, ISRAEL
| |
Collapse
|
27
|
Sun C, Ouyang M, Cao Z, Ma S, Alqublan H, Sriranganathan N, Wang Y, Lu C. Electroporation-delivered fluorescent protein biosensors for probing molecular activities in cells without genetic encoding. Chem Commun (Camb) 2015; 50:11536-9. [PMID: 25133322 PMCID: PMC5783554 DOI: 10.1039/c4cc04730c] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Fluorescent protein biosensors are typically implemented via genetic encoding which makes the examination of scarce cell samples impractical. By directly delivering the protein form of the biosensor into cells using electroporation, we detected intracellular molecular activity with the sample size down to ~100 cells with high spatiotemporal resolution.
Collapse
Affiliation(s)
- Chen Sun
- School of Biomedical Engineering and Sciences, Virginia Tech-Wake Forest University, Blacksburg, Virginia 24061, USA
| | | | | | | | | | | | | | | |
Collapse
|
28
|
Gomez-Godinez V, Preece D, Shi L, Khatibzadeh N, Rosales D, Pan Y, Lei L, Wang Y, Berns MW. Laser-induced shockwave paired with FRET: a method to study cell signaling. Microsc Res Tech 2015; 78:195-9. [PMID: 25639252 DOI: 10.1002/jemt.22463] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2014] [Revised: 12/18/2014] [Accepted: 12/18/2014] [Indexed: 11/10/2022]
Abstract
Cells within the body are subject to various forces; however, the details concerning the way in which cells respond to mechanical stimuli are not well understood. We demonstrate that laser-induced shockwaves (LIS) combined with biosensors based on fluorescence resonance energy transfer (FRET) is a promising new approach to study biological processes in single live cells. As "proof-of-concept," using a FRET biosensor, we show that in response to LIS, cells release intracellular calcium. With the parameters used, cells retain their morphology and remain viable. LIS combined with FRET permits observation of the cells immediate response to a sudden shear force.
Collapse
Affiliation(s)
- Veronica Gomez-Godinez
- Institute of Engineering in Medicine, University of California, San Diego 9500, Gilman Drive La Jolla, California, 92093-0435
| | | | | | | | | | | | | | | | | |
Collapse
|
29
|
Aung A, Seo YN, Lu S, Wang Y, Jamora C, del Álamo JC, Varghese S. 3D traction stresses activate protease-dependent invasion of cancer cells. Biophys J 2014; 107:2528-37. [PMID: 25468332 DOI: 10.1016/j.bpj.2014.07.078] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2014] [Revised: 06/12/2014] [Accepted: 07/01/2014] [Indexed: 10/25/2022] Open
Abstract
Cell invasion and migration that occurs, for example, in cancer metastasis is rooted in the ability of cells to navigate through varying levels of physical constraint exerted by the extracellular matrix. Cancer cells can invade matrices in either a protease-independent or a protease-dependent manner. An emerging critical component that influences the mode of cell invasion is the traction stresses generated by the cells in response to the physicostructural properties of the extracellular matrix. In this study, we have developed a reference-free quantitative assay for measuring three-dimensional (3D) traction stresses generated by cells during the initial stages of invasion into matrices exerting varying levels of mechanical resistance. Our results show that as cells encounter higher mechanical resistance, a larger fraction of them shift to protease-mediated invasion, and this process begins at lower values of cell invasion depth. On the other hand, the compressive stress generated by the cells at the onset of protease-mediated invasion is found to be independent of matrix stiffness, suggesting that 3D traction stress is a key factor in triggering protease-mediated cancer cell invasion. At low 3D compressive traction stresses, cells utilize bleb formation to indent the matrix in a protease independent manner. However, at higher stress values, cells utilize invadopodia-like structures to mediate protease-dependent invasion into the 3D matrix. The critical value of compressive traction stress at the transition from a protease-independent to a protease-dependent mode of invasion is found to be ∼165 Pa.
Collapse
Affiliation(s)
- Aereas Aung
- Department of Bioengineering, University of California-San Diego, La Jolla, California
| | - Young N Seo
- Department of Bioengineering, University of California-San Diego, La Jolla, California
| | - Shaoying Lu
- Department of Bioengineering, University of California-San Diego, La Jolla, California
| | - Yingxiao Wang
- Department of Bioengineering, University of California-San Diego, La Jolla, California
| | - Colin Jamora
- Department of Bioengineering, University of California-San Diego, La Jolla, California; IFOM-inStem Joint Research Laboratory, Bangalore, India
| | - Juan C del Álamo
- Department of Mechanical and Aerospace Engineering, University of California-San Diego, La Jolla, California; Institute of Engineering in Medicine, University of California-San Diego, La Jolla, California.
| | - Shyni Varghese
- Department of Bioengineering, University of California-San Diego, La Jolla, California; Institute of Engineering in Medicine, University of California-San Diego, La Jolla, California; IFOM-inStem Joint Research Laboratory, Bangalore, India.
| |
Collapse
|
30
|
Liu B, Lu S, Hu YL, Liao X, Ouyang M, Wang Y. RhoA and membrane fluidity mediates the spatially polarized Src/FAK activation in response to shear stress. Sci Rep 2014; 4:7008. [PMID: 25387906 PMCID: PMC4228346 DOI: 10.1038/srep07008] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2014] [Accepted: 10/07/2014] [Indexed: 01/05/2023] Open
Abstract
While Src plays crucial roles in shear stress-induced cellular processes, little is known on the spatiotemporal pattern of high shear stress (HSS)-induced Src activation. HSS (65 dyn/cm2) was applied on bovine aortic endothelial cells to visualize the dynamic Src activation at subcellular levels utilizing a membrane-targeted Src biosensor (Kras-Src) based on fluorescence resonance energy transfer (FRET). A polarized Src activation was observed with higher activity at the side facing the flow, which was enhanced by a cytochalasin D-mediated disruption of actin filaments but inhibited by a benzyl alcohol-mediated enhancement of membrane fluidity. Further experiments revealed that HSS decreased RhoA activity, with a constitutively active RhoA mutant inhibiting while a negative RhoA mutant enhancing the HSS-induced Src polarity. Cytochalasin D can restore the polarity in cells expressing the active RhoA mutant. Further results indicate that HSS stimulates FAK activation with a spatial polarity similar to Src. The inhibition of Src by PP1, as well as the perturbation of RhoA activity and membrane fluidity, can block this HSS-induced FAK polarity. These results indicate that the HSS-induced Src and subsequently FAK polarity depends on the coordination between intracellular tension distribution regulated by RhoA, its related actin structures and the plasma membrane fluidity.
Collapse
Affiliation(s)
- Bo Liu
- 1] Department of Biomedical Engineering, Dalian University of Technology, Dalian, Liaoning Province, 116024, P. R. China [2] Department of Bioengineering and the Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Shaoying Lu
- Department of Bioengineering, University of California at San Diego, CA 92093, USA
| | - Ying-li Hu
- Department of Bioengineering, University of California at San Diego, CA 92093, USA
| | - Xiaoling Liao
- 1] Department of Bioengineering and the Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA [2] Biomaterials and Live Cell Imaging Institute, Chongqing University of Science and Technology, Chongqing, 401331, P. R. China
| | - Mingxing Ouyang
- Department of Bioengineering, University of California at San Diego, CA 92093, USA
| | - Yingxiao Wang
- 1] Department of Bioengineering and the Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA [2] Department of Integrative and Molecular Physiology, Center for Biophysics and Computational Biology, Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA [3] Department of Bioengineering, University of California at San Diego, CA 92093, USA
| |
Collapse
|
31
|
Wan Q, Xu W, Yan JL, Yokota H, Na S. Distinctive subcellular inhibition of cytokine-induced SRC by salubrinal and fluid flow. PLoS One 2014; 9:e105699. [PMID: 25157407 PMCID: PMC4144888 DOI: 10.1371/journal.pone.0105699] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2014] [Accepted: 07/23/2014] [Indexed: 12/17/2022] Open
Abstract
A non-receptor protein kinase Src plays a crucial role in fundamental cell functions such as proliferation, migration, and differentiation. While inhibition of Src is reported to contribute to chondrocyte homeostasis, its regulation at a subcellular level by chemical inhibitors and mechanical stimulation has not been fully understood. In response to inflammatory cytokines and stress to the endoplasmic reticulum (ER) that increase proteolytic activities in chondrocytes, we addressed two questions: Do cytokines such as interleukin 1 beta (IL1β) and tumor necrosis factor alpha (TNFα) induce location-dependent Src activation? Can cytokine-induced Src activation be suppressed by chemically alleviating ER stress or by applying fluid flow? Using live cell imaging with two Src biosensors (i.e., cytosolic, and plasma membrane-bound biosensors) for a fluorescence resonance energy transfer (FRET) technique, we determined cytosolic Src activity as well as membrane-bound Src activity in C28/I2 human chondrocytes. In response to TNFα and IL1β, both cytosolic and plasma membrane-bound Src proteins were activated, but activation in the cytosol occurred earlier than that in the plasma membrane. Treatment with salubrinal or guanabenz, two chemical agents that attenuate ER stress, significantly decreased cytokine-induced Src activities in the cytosol, but not in the plasma membrane. In contrast, fluid flow reduced Src activities in the plasma membrane, but not in the cytosol. Collectively, the results demonstrate that Src activity is differentially regulated by salubrinal/guanabenz and fluid flow in the cytosol and plasma membrane.
Collapse
Affiliation(s)
- Qiaoqiao Wan
- Department of Biomedical Engineering, Indiana University-Purdue University Indianapolis, Indianapolis, Indiana, United States of America
| | - Wenxiao Xu
- Department of Orthopedics, Second Clinical Hospital of Harbin Medical University, Harbin, China
| | - Jing-long Yan
- Department of Orthopedics, Second Clinical Hospital of Harbin Medical University, Harbin, China
| | - Hiroki Yokota
- Department of Biomedical Engineering, Indiana University-Purdue University Indianapolis, Indianapolis, Indiana, United States of America
- Department of Anatomy and Cell Biology, Indiana University School of Medicine, Indianapolis, Indiana, United States of America
| | - Sungsoo Na
- Department of Biomedical Engineering, Indiana University-Purdue University Indianapolis, Indianapolis, Indiana, United States of America
- * E-mail:
| |
Collapse
|
32
|
Lu S, Seong J, Wang Y, Chang SC, Eichorst JP, Ouyang M, Li JYS, Chien S, Wang Y. Decipher the dynamic coordination between enzymatic activity and structural modulation at focal adhesions in living cells. Sci Rep 2014; 4:5756. [PMID: 25056908 PMCID: PMC4108961 DOI: 10.1038/srep05756] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2014] [Accepted: 06/23/2014] [Indexed: 02/06/2023] Open
Abstract
Focal adhesions (FAs) are dynamic subcellular structures crucial for cell adhesion, migration and differentiation. It remains an enigma how enzymatic activities in these local complexes regulate their structural remodeling in live cells. Utilizing biosensors based on fluorescence resonance energy transfer (FRET), we developed a correlative FRET imaging microscopy (CFIM) approach to quantitatively analyze the subcellular coordination between the enzymatic Src activation and the structural FA disassembly. CFIM reveals that the Src kinase activity only within the microdomain of lipid rafts at the plasma membrane is coupled with FA dynamics. FA disassembly at cell periphery was linearly dependent on this raft-localized Src activity, although cells displayed heterogeneous levels of response to stimulation. Within lipid rafts, the time delay between Src activation and FA disassembly was 1.2 min in cells seeded on low fibronectin concentration ([FN]) and 4.3 min in cells on high [FN]. CFIM further showed that the level of Src-FA coupling, as well as the time delay, was regulated by cell-matrix interactions, as a tight enzyme-structure coupling occurred in FA populations mediated by integrin αvβ₃, but not in those by integrin α₅β₁. Therefore, different FA subpopulations have distinctive regulation mechanisms between their local kinase activity and structural FA dynamics.
Collapse
Affiliation(s)
- Shaoying Lu
- Department of Bioengineering, Institute of Engineering in Medicine, University of California, San Diego, La Jolla, CA 92093-0435
- Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801
| | - Jihye Seong
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, IL 61801
- Current address: Korea Institute of Science and Technology (KIST), Seoul, South Korea
| | - Yi Wang
- Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801
| | - Shiou-chi Chang
- Department of Chemical Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801
| | - John Paul Eichorst
- Center of Biophysics and Computational Biology, Beckman Institute for Advanced Science and Technology, Department of Molecular and Integrative Physiology and, University of Illinois at Urbana-Champaign, Urbana, IL 61801
| | - Mingxing Ouyang
- Department of Bioengineering, Institute of Engineering in Medicine, University of California, San Diego, La Jolla, CA 92093-0435
- Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801
| | - Julie Y.-S. Li
- Department of Bioengineering, Institute of Engineering in Medicine, University of California, San Diego, La Jolla, CA 92093-0435
| | - Shu Chien
- Department of Bioengineering, Institute of Engineering in Medicine, University of California, San Diego, La Jolla, CA 92093-0435
| | - Yingxiao Wang
- Department of Bioengineering, Institute of Engineering in Medicine, University of California, San Diego, La Jolla, CA 92093-0435
- Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, IL 61801
- Center of Biophysics and Computational Biology, Beckman Institute for Advanced Science and Technology, Department of Molecular and Integrative Physiology and, University of Illinois at Urbana-Champaign, Urbana, IL 61801
| |
Collapse
|
33
|
Komiya E, Ohnuma K, Yamazaki H, Hatano R, Iwata S, Okamoto T, Dang NH, Yamada T, Morimoto C. CD26-mediated regulation of periostin expression contributes to migration and invasion of malignant pleural mesothelioma cells. Biochem Biophys Res Commun 2014; 447:609-15. [PMID: 24747072 DOI: 10.1016/j.bbrc.2014.04.037] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2014] [Accepted: 04/08/2014] [Indexed: 12/23/2022]
Abstract
Malignant pleural mesothelioma (MPM) is an aggressive malignancy arising from mesothelial lining of pleura. It is generally associated with a history of asbestos exposure and has a very poor prognosis, partly due to the lack of a precise understanding of the molecular mechanisms associated with its malignant behavior. In the present study, we expanded on our previous studies on the enhanced motility and increased CD26 expression in MPM cells, with a particular focus on integrin adhesion molecules. We found that expression of CD26 upregulates periostin secretion by MPM cells, leading to enhanced MPM cell migratory and invasive activity. Moreover, we showed that upregulation of periostin expression results from the nuclear translocation of the basic helix-loop-helix transcription factor Twist1, a process that is mediated by CD26-associated activation of Src phosphorylation. While providing new and profound insights into the molecular mechanisms involved in MPM biology, these findings may also lead to the development of novel therapeutic strategies for MPM.
Collapse
Affiliation(s)
- Eriko Komiya
- Department of Therapy Development and Innovation for Immune Disorders and Cancers, Graduate School of Medicine, Juntendo University, 2-1-1, Hongo, Bunkyo-ku, Tokyo 113-8421, Japan
| | - Kei Ohnuma
- Department of Therapy Development and Innovation for Immune Disorders and Cancers, Graduate School of Medicine, Juntendo University, 2-1-1, Hongo, Bunkyo-ku, Tokyo 113-8421, Japan.
| | - Hiroto Yamazaki
- Department of Therapy Development and Innovation for Immune Disorders and Cancers, Graduate School of Medicine, Juntendo University, 2-1-1, Hongo, Bunkyo-ku, Tokyo 113-8421, Japan
| | - Ryo Hatano
- Department of Therapy Development and Innovation for Immune Disorders and Cancers, Graduate School of Medicine, Juntendo University, 2-1-1, Hongo, Bunkyo-ku, Tokyo 113-8421, Japan
| | - Satoshi Iwata
- Department of Therapy Development and Innovation for Immune Disorders and Cancers, Graduate School of Medicine, Juntendo University, 2-1-1, Hongo, Bunkyo-ku, Tokyo 113-8421, Japan
| | - Toshihiro Okamoto
- Department of Therapy Development and Innovation for Immune Disorders and Cancers, Graduate School of Medicine, Juntendo University, 2-1-1, Hongo, Bunkyo-ku, Tokyo 113-8421, Japan
| | - Nam H Dang
- Division of Hematology/Oncology, University of Florida, 1600 SW Archer Road, Box 100278, Room MSB M410A, Gainesville, FL 32610, USA
| | - Taketo Yamada
- Department of Pathology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan
| | - Chikao Morimoto
- Department of Therapy Development and Innovation for Immune Disorders and Cancers, Graduate School of Medicine, Juntendo University, 2-1-1, Hongo, Bunkyo-ku, Tokyo 113-8421, Japan
| |
Collapse
|
34
|
Lei L, Lu S, Wang Y, Kim T, Mehta D, Wang Y. The role of mechanical tension on lipid raft dependent PDGF-induced TRPC6 activation. Biomaterials 2014; 35:2868-77. [PMID: 24397990 DOI: 10.1016/j.biomaterials.2013.12.030] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2013] [Accepted: 12/13/2013] [Indexed: 12/22/2022]
Abstract
Canonical transient receptor potential channel 6 (TRPC6) can play an important role in governing how cells perceive the surrounding material environment and regulate Ca(2+) signaling. We have designed a TRPC6 reporter based on fluorescence resonance energy transfer (FRET) to visualize the TRPC6-mediated calcium entry and hence TRPC6 activity in live cells with high spatiotemporal resolutions. In mouse embryonic fibroblasts (MEFs), platelet-derived growth factor BB (PDGF) can activate the TRPC6 reporter, mediated by phospholipase C (PLC). This TRPC6 activation occurred mainly at lipid rafts regions of the plasma membrane because disruption of lipid raft/caveolae by methyl-β-cyclodextrin (MβCD) or the expression of dominant-negative caveolin-1 inhibited the TRPC6 activity. Culturing cells on soft materials or releasing the intracellular tension by ML-7 reduced this PDGF-induced activation of TRPC6 without affecting the PDGF-regulated Src or inositol 1,4,5-trisphosphate (IP3) receptor function, suggesting a specific role of mechanical tension in regulating TRPC6. We further showed that the release of intracellular tension had similar effect on the diffusion coefficients of TRPC6 and a raft marker, confirming a strong coupling between TRPC6 and lipid rafts. Therefore, our results suggest that the TRPC6 activation mainly occurs at lipid rafts, which is regulated by the mechanical cues of surrounding materials.
Collapse
Affiliation(s)
- Lei Lei
- Department of Bioengineering & Beckman Institute for Advanced Science and Technology, University of Illinois, Urbana-Champaign, Urbana, IL 61801, United States; Department of Bioengineering & Institute of Engineering in Medicine, University of California, San Diego, La Jolla, CA 92093, United States
| | - Shaoying Lu
- Department of Bioengineering & Beckman Institute for Advanced Science and Technology, University of Illinois, Urbana-Champaign, Urbana, IL 61801, United States; Department of Bioengineering & Institute of Engineering in Medicine, University of California, San Diego, La Jolla, CA 92093, United States
| | - Yi Wang
- Department of Bioengineering & Beckman Institute for Advanced Science and Technology, University of Illinois, Urbana-Champaign, Urbana, IL 61801, United States
| | - Taejin Kim
- Department of Bioengineering & Beckman Institute for Advanced Science and Technology, University of Illinois, Urbana-Champaign, Urbana, IL 61801, United States
| | - Dolly Mehta
- Department of Pharmacology, College of Medicine, University of Illinois, Chicago, IL 60612, United States
| | - Yingxiao Wang
- Department of Bioengineering & Beckman Institute for Advanced Science and Technology, University of Illinois, Urbana-Champaign, Urbana, IL 61801, United States; Department of Bioengineering & Institute of Engineering in Medicine, University of California, San Diego, La Jolla, CA 92093, United States.
| |
Collapse
|
35
|
Lu S, Wang Y. Single-cell imaging of mechanotransduction in endothelial cells. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2014; 126:25-51. [PMID: 25081613 DOI: 10.1016/b978-0-12-394624-9.00002-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Endothelial cells (ECs) are constantly exposed to chemical and mechanical microenvironment in vivo. In mechanotransduction, cells can sense and translate the extracellular mechanical cues into intracellular biochemical signals, to regulate cellular processes. This regulation is crucial for many physiological functions, such as cell adhesion, migration, proliferation, and survival, as well as the progression of disease such as atherosclerosis. Here, we overview the current molecular understanding of mechanotransduction in ECs associated with atherosclerosis, especially those in response to physiological shear stress. The enabling technology of live-cell imaging has allowed the study of spatiotemporal molecular events and unprecedented understanding of intracellular signaling responses in mechanotransduction. Hence, we also introduce recent studies on mechanotransduction using single-cell imaging technologies.
Collapse
Affiliation(s)
- Shaoying Lu
- Department of Bioengineering, Institute of Engineering in Medicine, University of California, San Diego, La Jolla, California, USA
| | - Yingxiao Wang
- Department of Bioengineering, Institute of Engineering in Medicine, University of California, San Diego, La Jolla, California, USA
| |
Collapse
|
36
|
Distinct biophysical mechanisms of focal adhesion kinase mechanoactivation by different extracellular matrix proteins. Proc Natl Acad Sci U S A 2013; 110:19372-7. [PMID: 24222685 DOI: 10.1073/pnas.1307405110] [Citation(s) in RCA: 132] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Matrix mechanics controls cell fate by modulating the bonds between integrins and extracellular matrix (ECM) proteins. However, it remains unclear how fibronectin (FN), type 1 collagen, and their receptor integrin subtypes distinctly control force transmission to regulate focal adhesion kinase (FAK) activity, a crucial molecular signal governing cell adhesion/migration. Here we showed, using a genetically encoded FAK biosensor based on fluorescence resonance energy transfer, that FN-mediated FAK activation is dependent on the mechanical tension, which may expose its otherwise hidden FN synergy site to integrin α5. In sharp contrast, the ligation between the constitutively exposed binding motif of type 1 collagen and its receptor integrin α2 was surprisingly tension-independent to induce sufficient FAK activation. Although integrin α subunit determines mechanosensitivity, the ligation between α subunit and the ECM proteins converges at the integrin β1 activation to induce FAK activation. We further discovered that the interaction of the N-terminal protein 4.1/ezrin/redixin/moesin basic patch with phosphatidylinositol 4,5-biphosphate is crucial during cell adhesion to maintain the FAK activation from the inhibitory effect of nearby protein 4.1/ezrin/redixin/moesin acidic sites. Therefore, different ECM proteins either can transmit or can shield from mechanical forces to regulate cellular functions, with the accessibility of ECM binding motifs by their specific integrin α subunits determining the biophysical mechanisms of FAK activation during mechanotransduction.
Collapse
|
37
|
Kochanczyk M, Jaruszewicz J, Lipniacki T. Stochastic transitions in a bistable reaction system on the membrane. J R Soc Interface 2013; 10:20130151. [PMID: 23635492 DOI: 10.1098/rsif.2013.0151] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Transitions between steady states of a multi-stable stochastic system in the perfectly mixed chemical reactor are possible only because of stochastic switching. In realistic cellular conditions, where diffusion is limited, transitions between steady states can also follow from the propagation of travelling waves. Here, we study the interplay between the two modes of transition for a prototype bistable system of kinase-phosphatase interactions on the plasma membrane. Within microscopic kinetic Monte Carlo simulations on the hexagonal lattice, we observed that for finite diffusion the behaviour of the spatially extended system differs qualitatively from the behaviour of the same system in the well-mixed regime. Even when a small isolated subcompartment remains mostly inactive, the chemical travelling wave may propagate, leading to the activation of a larger compartment. The activating wave can be induced after a small subdomain is activated as a result of a stochastic fluctuation. Such a spontaneous onset of activity is radically more probable in subdomains characterized by slower diffusion. Our results show that a local immobilization of substrates can lead to the global activation of membrane proteins by the mechanism that involves stochastic fluctuations followed by the propagation of a semi-deterministic travelling wave.
Collapse
Affiliation(s)
- Marek Kochanczyk
- Institute of Fundamental Technological Research, Polish Academy of Sciences, Warsaw, Poland
| | | | | |
Collapse
|
38
|
Tiwari A, Jung JJ, Inamdar SM, Nihalani D, Choudhury A. The myosin motor Myo1c is required for VEGFR2 delivery to the cell surface and for angiogenic signaling. Am J Physiol Heart Circ Physiol 2012; 304:H687-96. [PMID: 23262137 DOI: 10.1152/ajpheart.00744.2012] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Vascular endothelial growth factor receptor-2 (VEGFR2) is a receptor tyrosine kinase that is expressed in endothelial cells and regulates angiogenic signal transduction under both physiological and pathological conditions. VEGFR2 turnover at the plasma membrane (PM) is regulated by its transport through endocytic and secretory transport pathways. Short-range cargo trafficking along actin filaments is commonly regulated by motor proteins of myosin superfamily. In the current study, performed in primary human endothelial cells, we demonstrate that unconventional myosin 1c (Myo1c; class I family member) regulates the localization of VEGFR2 at the PM. We further demonstrate that the recruitment of VEGFR2 to the PM and its colocalization with Myo1c and caveolin-1 occur in response to VEGF-A (VEGF) stimulation. In addition, VEGF-induced delivery of VEGFR2 to the cell surface requires Myo1c; surface VEGFR2 levels are reduced in the absence of Myo1c and, more importantly, are restored by the overexpression of wild-type but not mutant Myo1c. Subcellular density gradient fractionation revealed that partitioning of VEGFR2 into caveolin-1- and Myo1c-enriched membrane fractions is dependent on VEGF stimulation. Myo1c depletion resulted in increased VEGF-induced VEGFR2 transport to the lysosomes for degradation and was rescued by applying either brefeldin A, which blocks trafficking between the endoplasmic reticulum and the Golgi complex, or dynasore, an inhibitor of dynamin-mediated endocytosis. Myo1c depletion also reduced VEGF-induced VEGFR2 phosphorylation at Y1175 and phosphorylation-dependent activation of ERK1/2 and c-Src kinase, leading to reduced cell proliferation and cell migration. This is the first report demonstrating that Myo1c is an important mediator of VEGF-induced VEGFR2 delivery to the cell surface and plays a role in angiogenic signaling.
Collapse
Affiliation(s)
- Ajit Tiwari
- Department of Anatomy and Cell Biology, University of Iowa, Iowa City, IA 52242, USA
| | | | | | | | | |
Collapse
|
39
|
Boscher C, Zheng YZ, Lakshminarayan R, Johannes L, Dennis JW, Foster LJ, Nabi IR. Galectin-3 protein regulates mobility of N-cadherin and GM1 ganglioside at cell-cell junctions of mammary carcinoma cells. J Biol Chem 2012; 287:32940-52. [PMID: 22846995 DOI: 10.1074/jbc.m112.353334] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Galectin-3 binding to cell surface glycoproteins, including branched N-glycans generated by N-acetylglucosaminyltransferase V (Mgat5) activity, forms a multivalent, heterogeneous, and dynamic lattice. This lattice has been shown to regulate integrin and receptor tyrosine kinase signaling promoting tumor cell migration. N-cadherin is a homotypic cell-cell adhesion receptor commonly overexpressed in tumor cells that contributes to cell motility. Here we show that galectin-3 and N-cadherin interact and colocalize with the lipid raft marker GM1 ganglioside in cell-cell junctions of mammary epithelial cancer cells. Disruption of the lattice by deletion of Mgat5, siRNA depletion of galectin-3, or competitive inhibition with lactose stabilizes cell-cell junctions. It also reduces, in a p120-catenin-dependent manner, the dynamic pool of junctional N-cadherin. Proteomic analysis of detergent-resistant membranes (DRMs) revealed that the galectin lattice opposes entry of many proteins into DRM rafts. N-cadherin and catenins are present in DRMs; however, their DRM distribution is not significantly affected by lattice disruption. Galectin lattice integrity increases the mobile fraction of the raft marker, GM1 ganglioside binding cholera toxin B subunit Ctb, at cell-cell contacts in a p120-catenin-independent manner, but does not affect the mobility of either Ctb-labeled GM1 or GFP-coupled N-cadherin in nonjunctional regions. Our results suggest that the galectin lattice independently enhances lateral molecular diffusion by direct interaction with specific glycoconjugates within the adherens junction. By promoting exchange between raft and non-raft microdomains as well as molecular dynamics within junction-specific raft microdomains, the lattice may enhance turnover of N-cadherin and other glycoconjugates that determine junctional stability and rates of cell migration.
Collapse
Affiliation(s)
- Cécile Boscher
- Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
| | | | | | | | | | | | | |
Collapse
|
40
|
Widely accessible method for superresolution fluorescence imaging of living systems. Proc Natl Acad Sci U S A 2012; 109:10909-14. [PMID: 22711840 DOI: 10.1073/pnas.1204917109] [Citation(s) in RCA: 149] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Superresolution fluorescence microscopy overcomes the diffraction resolution barrier and allows the molecular intricacies of life to be revealed with greatly enhanced detail. However, many current superresolution techniques still face limitations and their implementation is typically associated with a steep learning curve. Patterned illumination-based superresolution techniques [e.g., stimulated emission depletion (STED), reversible optically-linear fluorescence transitions (RESOLFT), and saturated structured illumination microscopy (SSIM)] require specialized equipment, whereas single-molecule-based approaches [e.g., stochastic optical reconstruction microscopy (STORM), photo-activation localization microscopy (PALM), and fluorescence-PALM (F-PALM)] involve repetitive single-molecule localization, which requires its own set of expertise and is also temporally demanding. Here we present a superresolution fluorescence imaging method, photochromic stochastic optical fluctuation imaging (pcSOFI). In this method, irradiating a reversibly photoswitching fluorescent protein at an appropriate wavelength produces robust single-molecule intensity fluctuations, from which a superresolution picture can be extracted by a statistical analysis of the fluctuations in each pixel as a function of time, as previously demonstrated in SOFI. This method, which uses off-the-shelf equipment, genetically encodable labels, and simple and rapid data acquisition, is capable of providing two- to threefold-enhanced spatial resolution, significant background rejection, markedly improved contrast, and favorable temporal resolution in living cells. Furthermore, both 3D and multicolor imaging are readily achievable. Because of its ease of use and high performance, we anticipate that pcSOFI will prove an attractive approach for superresolution imaging.
Collapse
|
41
|
Fuentes DE, Butler PJ. Coordinated Mechanosensitivity of Membrane Rafts and Focal Adhesions. Cell Mol Bioeng 2012; 5:143-154. [PMID: 23487555 DOI: 10.1007/s12195-012-0225-z] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Endothelial cells sense mechanical forces of blood flow through mechanisms that involve focal adhesions (FAs). The mechanosensitive pathways that originate from FA-associated integrin activation may involve membrane rafts, small cholesterol- and sphigolipid-rich domains that are either immobilized, by virtue of their attachment to the cytoskeleton, or highly mobile in the plane of the plasma membrane. In this study, we fluorescently labeled non-mobile and mobile populations of GM1, a ganglioside associated with lipid rafts, and transfected cells with the red fluorescent protein-(RFP-) talin, an indicator of integrin activation at FAs, in order to determine the kinetics and sequential order of raft and talin mechanosensitivity. Cells were imaged under confocal microscopy during mechanical manipulation of a FA induced by a fibronectin (FN)-functionalized nanoelectrode with feedback control of position. First, FA deformation led to long range deformation of immobile rafts followed by active recoil of a subpopulation of displaced rafts. Second, initial adhesion between the FN-probe and the cell induced rapid accumulation of GM1 at the probe site with a time constant of 1.7 s. Talin accumulated approximately 20 s later with a time constant of 0.6 s. Third, a 1 μm deformation of the FA lead to immediate (0.3 s) increase in GM1 fluorescence and a later (6 s) increase in talin. Fourth, long term deformation of FAs led to continual GM1 accumulation at the probe site that was reversed upon removal of the deformation. These results demonstrate that rafts are directly mechanosensitive and that raft mobility may enable the earliest events related to FA mechanosensing and reinforcement upon force application.
Collapse
Affiliation(s)
- Daniela E Fuentes
- Department of Bioengineering, The Pennsylvania State University, 205 Hallowell Building, University Park, PA 16802, USA
| | | |
Collapse
|
42
|
Baumann P, Thiele W, Cremers N, Muppala S, Krachulec J, Diefenbacher M, Kassel O, Mudduluru G, Allgayer H, Frame M, Sleeman JP. CD24 interacts with and promotes the activity of c-src within lipid rafts in breast cancer cells, thereby increasing integrin-dependent adhesion. Cell Mol Life Sci 2012; 69:435-48. [PMID: 21710320 PMCID: PMC11114536 DOI: 10.1007/s00018-011-0756-9] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2010] [Revised: 06/06/2011] [Accepted: 06/15/2011] [Indexed: 01/22/2023]
Abstract
Expression of the glycosylphosphatidylinositol-anchored membrane protein CD24 correlates with a poor prognosis for many human cancers, and in experimental tumors can promote metastasis. However, the mechanism by which CD24 contributes to tumor progression remains unclear. Here we report that in MTLy breast cancer cells CD24 interacts with and augments the kinase activity of c-src, a protein strongly implicated in promoting invasion and metastasis. This occurs within and is dependent upon intact lipid rafts. CD24-augmented c-src kinase activity increased formation of focal adhesion complexes, accelerated phosphorylation of FAK and paxillin and consequently enhanced integrin-mediated adhesion. Loss and gain of function approaches showed that c-src activity is necessary and sufficient to mediate the effects of CD24 on integrin-dependent adhesion and cell spreading, as well as on invasion. Together these results indicate that c-src is a CD24-activated mediator that promotes integrin-mediated adhesion and invasion, and suggest a mechanism by which CD24 might contribute to tumor progression through stimulating the activity of c-src or another member of the Src family.
Collapse
Affiliation(s)
- Petra Baumann
- Karlsruhe Institute of Technology, Institut für Toxikologie und Genetik, 76021 Karlsruhe, Germany
| | - Wilko Thiele
- Karlsruhe Institute of Technology, Institut für Toxikologie und Genetik, 76021 Karlsruhe, Germany
- University of Heidelberg, Medical Faculty Mannheim, 68167 Mannheim, Germany
| | - Natascha Cremers
- Karlsruhe Institute of Technology, Institut für Toxikologie und Genetik, 76021 Karlsruhe, Germany
- University of Heidelberg, Medical Faculty Mannheim, 68167 Mannheim, Germany
| | - Santoshi Muppala
- University of Heidelberg, Medical Faculty Mannheim, 68167 Mannheim, Germany
| | - Justyna Krachulec
- University of Heidelberg, Medical Faculty Mannheim, 68167 Mannheim, Germany
| | - Markus Diefenbacher
- Karlsruhe Institute of Technology, Institut für Toxikologie und Genetik, 76021 Karlsruhe, Germany
| | - Olivier Kassel
- Karlsruhe Institute of Technology, Institut für Toxikologie und Genetik, 76021 Karlsruhe, Germany
| | - Giridhar Mudduluru
- University of Heidelberg, Medical Faculty Mannheim, 68167 Mannheim, Germany
| | - Heike Allgayer
- University of Heidelberg, Medical Faculty Mannheim, 68167 Mannheim, Germany
| | - Margaret Frame
- Institute of Genetics and Molecular Medicine, University of Edinburgh, Western General Hospital, Edinburgh, EH4 2XR United Kingdom
| | - Jonathan P. Sleeman
- Karlsruhe Institute of Technology, Institut für Toxikologie und Genetik, 76021 Karlsruhe, Germany
- University of Heidelberg, Medical Faculty Mannheim, 68167 Mannheim, Germany
- Centre for Biomedicine and Medical Technology Mannheim (CBTM), Universitätsmedizin Mannheim, University of Heidelberg, TRIDOMUS-Gebäude Haus C, Ludolf-Krehl-Str. 13–17, 68167 Mannheim, Germany
| |
Collapse
|
43
|
Zhou X, Herbst-Robinson KJ, Zhang J. Visualizing dynamic activities of signaling enzymes using genetically encodable FRET-based biosensors from designs to applications. Methods Enzymol 2012; 504:317-40. [PMID: 22264542 DOI: 10.1016/b978-0-12-391857-4.00016-1] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Living cells respond to various environmental cues and process them into a series of spatially and temporally regulated signaling events, which can be tracked in real time with an expanding repertoire of genetically encodable FRET-based biosensors. A series of these biosensors, designed to track dynamic activities of signaling enzymes such as protein kinases and small GTPases, have yielded invaluable information regarding the spatiotemporal regulation of these enzymes, shedding light on the orchestration of signaling pathways within the native cellular context. In this chapter, we first review the generalizable modular designs of FRET-based biosensors, followed by a detailed discussion about biosensors for reporting protein kinase activities and GTPase activation. Two general designs, uni- and bimolecular reporters, will be discussed with an analysis of their strengths and limitations. Finally, an example of using both uni- and bimolecular kinase activity reporters to visualize PKA activity in living cells will be presented to provide practical tips for using these biosensors to explore specific biological systems.
Collapse
Affiliation(s)
- Xin Zhou
- Department of Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | | | | |
Collapse
|
44
|
Tang N, Farah B, He M, Fox S, Malouf A, Littner Y, Bearer CF. Ethanol causes the redistribution of L1 cell adhesion molecule in lipid rafts. J Neurochem 2011; 119:859-67. [PMID: 21884525 DOI: 10.1111/j.1471-4159.2011.07467.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Fetal alcohol spectrum disorder is estimated to affect 1% of live births. The similarities between children with fetal alcohol syndrome and those with mutations in the gene encoding L1 cell adhesion molecule (L1) implicates L1 as a target of ethanol developmental neurotoxicity. Ethanol specifically inhibits the neurite outgrowth promoting function of L1 at pharmacologic concentrations. Emerging evidence shows that localized disruption of the lipid rafts reduces L1-mediated neurite outgrowth. We hypothesize that ethanol impairment of the association of L1 with lipid rafts is a mechanism underlying ethanol's inhibition of L1-mediated neurite outgrowth. In this study, we examine the effects of ethanol on the association of L1 and lipid rafts. We show that, in vitro, L1 but not N-cadherin shifts into lipid rafts following treatment with 25 mM ethanol. The ethanol concentrations causing this effect are similar to those inhibiting L1-mediated neurite outgrowth. Increasing chain length of the alcohol demonstrates the same cutoff as that previously shown for inhibition of L1-L1 binding. In addition, in cerebellar granule neurons in which lipid rafts are disrupted with methyl-beta-cyclodextrin, the rate of L1-mediated neurite outgrowth on L1-Fc is reduced to background rate and that this background rate is not ethanol sensitive. These data indicate that ethanol may inhibit L1-mediated neurite outgrowth by retarding L1 trafficking through a lipid raft compartment.
Collapse
Affiliation(s)
- Ningfeng Tang
- Department of Pediatrics, University of Maryland School of Medicine, Baltimore, Maryland 21209, USA
| | | | | | | | | | | | | |
Collapse
|
45
|
Lu S, Kim TJ, Chen CE, Ouyang M, Seong J, Liao X, Wang Y. Computational analysis of the spatiotemporal coordination of polarized PI3K and Rac1 activities in micro-patterned live cells. PLoS One 2011; 6:e21293. [PMID: 21738630 PMCID: PMC3124492 DOI: 10.1371/journal.pone.0021293] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2010] [Accepted: 05/24/2011] [Indexed: 12/31/2022] Open
Abstract
Polarized molecular activities play important roles in guiding the cell toward persistent and directional migration. In this study, the polarized distributions of the activities of phosphatidylinositol 3-kinase (PI3K) and the Rac1 small GTPase were monitored using chimeric fluorescent proteins (FPs) in cells constrained on micro-patterned strips, with one end connecting to a neighboring cell (junction end) and the other end free of cell-cell contact (free end). The recorded spatiotemporal dynamics of the fluorescent intensity from different cells was scaled into a uniform coordinate system and applied to compute the molecular activity landscapes in space and time. The results revealed different polarization patterns of PI3K and Rac1 activity induced by the growth factor stimulation. The maximal intensity of different FPs, and the edge position and velocity at the free end were further quantified to analyze their correlation and decipher the underlying signaling sequence. The results suggest that the initiation of the edge extension occurred before the activation of PI3K, which led to a stable extension of the free end followed by the Rac1 activation. Therefore, the results support a concerted coordination of sequential signaling events and edge dynamics, underscoring the important roles played by PI3K activity at the free end in regulating the stable lamellipodia extension and cell migration. Meanwhile, the quantification methods and accompanying software developed can provide a convenient and powerful computational analysis platform for the study of spatiotemporal molecular distribution and hierarchy in live cells based on fluorescence images.
Collapse
Affiliation(s)
- Shaoying Lu
- Department of Bioengineering, University of Illinois at Urbana-Champaign, Champaign, Illinois, United States of America
| | | | | | | | | | | | | |
Collapse
|
46
|
Kiselev VY, Marenduzzo D, Goryachev AB. Lateral dynamics of proteins with polybasic domain on anionic membranes: a dynamic Monte-Carlo study. Biophys J 2011; 100:1261-70. [PMID: 21354399 DOI: 10.1016/j.bpj.2011.01.025] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2010] [Accepted: 01/13/2011] [Indexed: 10/18/2022] Open
Abstract
Positively charged polybasic domains are essential for recruiting multiple signaling proteins, such as Ras GTPases and Src kinase, to the negatively charged cellular membranes. Much less, however, is known about the influence of electrostatic interactions on the lateral dynamics of these proteins. We developed a dynamic Monte-Carlo automaton that faithfully simulates lateral diffusion of the adsorbed positively charged oligopeptides as well as the dynamics of mono- (phosphatidylserine) and polyvalent (PIP(2)) anionic lipids within the bilayer. In agreement with earlier results, our simulations reveal lipid demixing that leads to the formation of a lipid shell associated with the peptide. The computed association times and average numbers of bound lipids demonstrate that tetravalent PIP(2) interacts with the peptide much more strongly than monovalent lipid. On the spatially homogeneous membrane, the lipid shell affects the behavior of the peptide only by weakly reducing its lateral mobility. However, spatially heterogeneous distributions of monovalent lipids are found to produce peptide drift, the velocity of which is determined by the total charge of the peptide-lipid complex. We hypothesize that this predicted phenomenon may affect the spatial distribution of proteins with polybasic domains in the context of cell-signaling events that alter the local density of monovalent anionic lipids.
Collapse
Affiliation(s)
- Vladimir Yu Kiselev
- Centre for Systems Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | | | | |
Collapse
|
47
|
Abstract
The Src/FAK complex is involved in many signaling pathways and plays crucial roles in cell adhesion/migration. It becomes clear that the subcellular localization of Src and FAK is crucial for their activities and functions. In this article, we first overview the molecular mechanisms and functions of Src and FAK involved in cell adhesion/migration. We then introduce the development of genetically encoded biosensors based on fluorescence resonance energy transfer (FRET) to visualize the activities of Src and FAK in live cells with high spatiotemporal resolutions. Different kinds of signal peptides targeting subcellular compartments are also discussed. FRET-based biosensors fused with these targeting signals peptides are further introduced to provide an overview on how these targeting signals can facilitate the localization of biosensors to continuously monitor the local activity of Src and FAK at subcellular compartments. In summary, genetically-encoded FRET biosensors integrated with subcellular compartment-targeting signals can provide powerful tools for the visualization of subcellular Src and FAK activities in live cells and advance our in-depth understanding of Src/FAK functions at different subcellular compartments.
Collapse
Affiliation(s)
- Jihye Seong
- Neuroscience Program, University of Illinois, Urbana-Champaign, Urbana, IL 61801, USA
| | | | | |
Collapse
|
48
|
Mehta S, Zhang J. Reporting from the field: genetically encoded fluorescent reporters uncover signaling dynamics in living biological systems. Annu Rev Biochem 2011; 80:375-401. [PMID: 21495849 PMCID: PMC4384825 DOI: 10.1146/annurev-biochem-060409-093259] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Real-time visualization of a wide range of biochemical processes in living systems is being made possible through the development and application of genetically encoded fluorescent reporters. These versatile biosensors have proven themselves tailor-made to the study of signal transduction, and in this review, we discuss some of the unique insights that they continue to provide regarding the spatial organization and dynamic regulation of intracellular signaling networks. In addition, we explore the more recent push to expand the scope of biological phenomena that can be monitored using these reporters, while also considering the potential to integrate this highly adaptable technology with a number of emerging techniques that may significantly broaden our view of how networks of biochemical processes shape larger biological phenomena.
Collapse
Affiliation(s)
- Sohum Mehta
- Department of Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
| | - Jin Zhang
- Department of Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
- Solomon H. Snyder Department of Neuroscience and Department of Oncology, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
| |
Collapse
|
49
|
Sadegh Zadeh K. A synergic simulation-optimization approach for analyzing biomolecular dynamics in living organisms. Comput Biol Med 2010; 41:24-36. [PMID: 21106190 DOI: 10.1016/j.compbiomed.2010.11.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2010] [Revised: 11/01/2010] [Accepted: 11/02/2010] [Indexed: 12/14/2022]
Abstract
A synergic duo simulation-optimization approach was developed and implemented to study protein-substrate dynamics and binding kinetics in living organisms. The forward problem is a system of several coupled nonlinear partial differential equations which, with a given set of kinetics and diffusion parameters, can provide not only the commonly used bleached area-averaged time series in fluorescence microscopy experiments but more informative full biomolecular/drug space-time series and can be successfully used to study dynamics of both Dirac and Gaussian fluorescence-labeled biomacromolecules in vivo. The incomplete Cholesky preconditioner was coupled with the finite difference discretization scheme and an adaptive time-stepping strategy to solve the forward problem. The proposed approach was validated with analytical as well as reference solutions and used to simulate dynamics of GFP-tagged glucocorticoid receptor (GFP-GR) in mouse cancer cell during a fluorescence recovery after photobleaching experiment. Model analysis indicates that the commonly practiced bleach spot-averaged time series is not an efficient approach to extract physiological information from the fluorescence microscopy protocols. It was recommended that experimental biophysicists should use full space-time series, resulting from experimental protocols, to study dynamics of biomacromolecules and drugs in living organisms. It was also concluded that in parameterization of biological mass transfer processes, setting the norm of the gradient of the penalty function at the solution to zero is not an efficient stopping rule to end the inverse algorithm. Theoreticians should use multi-criteria stopping rules to quantify model parameters by optimization.
Collapse
Affiliation(s)
- Kouroush Sadegh Zadeh
- Fischell Department of Bioengineering, University of Maryland at College Park, MD 20742, USA.
| |
Collapse
|
50
|
Sen A, O'Malley K, Wang Z, Raj GV, Defranco DB, Hammes SR. Paxillin regulates androgen- and epidermal growth factor-induced MAPK signaling and cell proliferation in prostate cancer cells. J Biol Chem 2010; 285:28787-95. [PMID: 20628053 DOI: 10.1074/jbc.m110.134064] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Although transcriptional effects of androgens have been extensively studied, mechanisms regulating transcription-independent (nongenomic) androgen actions are poorly understood. Previously, we have shown that paxillin, a multidomain adaptor protein, is a critical regulator of testosterone-induced MAPK-signaling during Xenopus oocyte maturation. Here we examine the nongenomic effects of dihydrotestosterone (DHT) in prostate cancer cells, focusing on how paxillin mediates Erk signaling and downstream physiologic actions. We show that in LnCAP cells DHT functions as a growth factor that indirectly activates the EGF-receptor (EGFR) via androgen receptor binding and matrix metalloproteinase-mediated release of EGFR ligands. Interestingly, siRNA-mediated knockdown of paxillin expression in androgen-dependent LnCAP cells as well as in androgen-independent PC3 cells abrogates DHT- and/or EGF-induced Erk signaling. Furthermore, EGFR-induced Erk activation requires Src-mediated phosphorylation of paxillin on tyrosines 31/118. In contrast, paxillin is not required for PKC-induced Erk signaling. However, Erk-mediated phosphorylation of paxillin on serines 83/126/130 is still needed for both EGFR and PKC-mediated cellular proliferation. Thus, paxillin serves as a specific upstream regulator of Erk in response to receptor-tyrosine kinase signaling but as a general regulator of downstream Erk actions regardless of agonist. Importantly, Erk-mediated serine phosphorylation of paxillin is also required for DHT-induced prostate-specific antigen mRNA expression in LnCAP cells as well as EGF-induced cyclin D1 mRNA expression in PC3 cells, suggesting that paxillin may regulate prostate cancer proliferation by serving as a liaison between extra-nuclear kinase signaling and intra-nuclear transcriptional signals. Thus, paxillin may prove to be a novel diagnostic or therapeutic target in prostate cancer.
Collapse
Affiliation(s)
- Aritro Sen
- Department of Medicine, Division of Endocrinology, University of Rochester Medical Center, Rochester, New York 14642, USA
| | | | | | | | | | | |
Collapse
|