1
|
Ulc A, Zeug A, Bauch J, van Leeuwen S, Kuhlmann T, ffrench-Constant C, Ponimaskin E, Faissner A. The guanine nucleotide exchange factor Vav3 modulates oligodendrocyte precursor differentiation and supports remyelination in white matter lesions. Glia 2018; 67:376-392. [DOI: 10.1002/glia.23548] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Revised: 09/03/2018] [Accepted: 09/04/2018] [Indexed: 12/13/2022]
Affiliation(s)
- Annika Ulc
- Department of Cell Morphology and Molecular Neurobiology; Ruhr-University Bochum; Germany
| | - Andre Zeug
- Cellular Neurophysiology, Centre for Physiology; Hannover Medical School; Hannover Germany
| | - Juliane Bauch
- Department of Cell Morphology and Molecular Neurobiology; Ruhr-University Bochum; Germany
| | - Simon van Leeuwen
- Department of Cell Morphology and Molecular Neurobiology; Ruhr-University Bochum; Germany
| | - Tanja Kuhlmann
- Institute of Neuropathology; University Hospital Münster; Germany
| | | | - Evgeni Ponimaskin
- Cellular Neurophysiology, Centre for Physiology; Hannover Medical School; Hannover Germany
| | - Andreas Faissner
- Department of Cell Morphology and Molecular Neurobiology; Ruhr-University Bochum; Germany
| |
Collapse
|
2
|
Goryashchenko AS, Khrenova MG, Savitsky AP. Detection of protease activity by fluorescent protein FRET sensors: from computer simulation to live cells. Methods Appl Fluoresc 2018; 6:022001. [DOI: 10.1088/2050-6120/aa9e47] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
|
3
|
Miroshnikova YA, Rozenberg GI, Cassereau L, Pickup M, Mouw JK, Ou G, Templeman KL, Hannachi EI, Gooch KJ, Sarang-Sieminski AL, García AJ, Weaver VM. α5β1-Integrin promotes tension-dependent mammary epithelial cell invasion by engaging the fibronectin synergy site. Mol Biol Cell 2017; 28:2958-2977. [PMID: 28877984 PMCID: PMC5662256 DOI: 10.1091/mbc.e17-02-0126] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Revised: 08/25/2017] [Accepted: 08/29/2017] [Indexed: 12/13/2022] Open
Abstract
Fibronectin-ligated α5β1 integrin promotes malignancy by inducing tissue tension. Tumors are fibrotic and characterized by abundant, remodeled, and cross-linked collagen that stiffens the extracellular matrix stroma. The stiffened collagenous stroma fosters malignant transformation of the tissue by increasing tumor cell tension to promote focal adhesion formation and potentiate growth factor receptor signaling through kinase. Importantly, collagen cross-linking requires fibronectin (FN). Fibrotic tumors contain abundant FN, and tumor cells frequently up-regulate the FN receptor α5β1 integrin. Using transgenic and xenograft models and tunable two- and three-dimensional substrates, we show that FN-bound α5β1 integrin promotes tension-dependent malignant transformation through engagement of the synergy site that enhances integrin adhesion force. We determined that ligation of the synergy site of FN permits tumor cells to engage a zyxin-stabilized, vinculin-linked scaffold that facilitates nucleation of phosphatidylinositol (3,4,5)-triphosphate at the plasma membrane to enhance phosphoinositide 3-kinase (PI3K)-dependent tumor cell invasion. The data explain why rigid collagen fibrils potentiate PI3K activation to promote malignancy and offer a perspective regarding the consistent up-regulation of α5β1 integrin and FN in many tumors and their correlation with cancer aggression.
Collapse
Affiliation(s)
- Y A Miroshnikova
- Department of Surgery, Center for Bioengineering and Tissue Regeneration, University of California, San Francisco, San Francisco, CA 94143
| | - G I Rozenberg
- Institute for Medicine and Engineering, University of Pennsylvania, Philadelphia, PA 19104
| | - L Cassereau
- Department of Surgery, Center for Bioengineering and Tissue Regeneration, University of California, San Francisco, San Francisco, CA 94143
| | - M Pickup
- Department of Surgery, Center for Bioengineering and Tissue Regeneration, University of California, San Francisco, San Francisco, CA 94143
| | - J K Mouw
- Department of Surgery, Center for Bioengineering and Tissue Regeneration, University of California, San Francisco, San Francisco, CA 94143
| | - G Ou
- Department of Surgery, Center for Bioengineering and Tissue Regeneration, University of California, San Francisco, San Francisco, CA 94143
| | - K L Templeman
- Woodruff School of Mechanical Engineering, Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA 30332
| | - E-I Hannachi
- Woodruff School of Mechanical Engineering, Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA 30332
| | - K J Gooch
- Institute for Medicine and Engineering, University of Pennsylvania, Philadelphia, PA 19104
| | - A L Sarang-Sieminski
- Institute for Medicine and Engineering, University of Pennsylvania, Philadelphia, PA 19104
| | - A J García
- Woodruff School of Mechanical Engineering, Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA 30332
| | - V M Weaver
- Department of Surgery, Center for Bioengineering and Tissue Regeneration, University of California, San Francisco, San Francisco, CA 94143 .,Department of Anatomy and Department of Bioengineering and Therapeutic Sciences, Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research and Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, San Francisco, CA 94143
| |
Collapse
|
4
|
Jiang L, Zhao X, Zheng C, Li F, Maclean JL, Chen F, Swami A, Qian H, Zhu J, Ge L. The quantitative detection of the uptake and intracellular fate of albumin nanoparticles. RSC Adv 2015. [DOI: 10.1039/c5ra01683e] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Little has been investigated about the intracellular fate of organic nanoparticles (NPs), which is important for the safety and drug delivery efficiency of NPs. In this work, the intracellular disassociation and hydrolysis of albumin NPs were detected based on FRET.
Collapse
Affiliation(s)
- Liqun Jiang
- School of Pharmacy
- China Pharmaceutical University
- Nanjing
- P.R. China
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy
| | - Xin Zhao
- Center for Biomedical Engineering
- Department of Medicine
- Brigham and Women's Hospital
- Harvard Medical School
- Boston
| | - Chunli Zheng
- School of Pharmacy
- China Pharmaceutical University
- Nanjing
- P.R. China
| | - Fang Li
- School of Pharmacy
- China Pharmaceutical University
- Nanjing
- P.R. China
- School of Pharmacy
| | | | - Fangcheng Chen
- School of Pharmacy
- China Pharmaceutical University
- Nanjing
- P.R. China
| | - Archana Swami
- Department of Anesthesia
- Brigham and Women's Hospital
- Harvard Medical School
- Boston
- USA
| | - Hai Qian
- School of Pharmacy
- China Pharmaceutical University
- Nanjing
- P.R. China
| | - Jiabi Zhu
- School of Pharmacy
- China Pharmaceutical University
- Nanjing
- P.R. China
| | - Liang Ge
- School of Pharmacy
- China Pharmaceutical University
- Nanjing
- P.R. China
| |
Collapse
|
5
|
Wang D, Ren AM, Guo JF, Zou LY, Huang S. Computational design of a two-photon excited FRET-based ratiometric fluorescent Cu2+ probe for living cell imaging. RSC Adv 2015. [DOI: 10.1039/c5ra18393f] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
A novel TP FRET ratiometric fluorescent probe 2a for Cu2+ is designed. 2a has a large TPA peak in the near-infrared light region and its energy transfer efficiency is nearly 100%.
Collapse
Affiliation(s)
- Dan Wang
- Institute of Theoretical Chemistry
- Jilin University
- Changchun 130023
- People's Republic of China
| | - Ai-Min Ren
- Institute of Theoretical Chemistry
- Jilin University
- Changchun 130023
- People's Republic of China
| | - Jing-Fu Guo
- School of Physics
- Northeast Normal University
- Changchun 130021
- People's Republic of China
| | - Lu-Yi Zou
- Institute of Theoretical Chemistry
- Jilin University
- Changchun 130023
- People's Republic of China
| | - Shuang Huang
- School of Mathematics and Physics
- Changzhou University
- Changzhou 213164
- People's Republic of China
| |
Collapse
|
6
|
Johnsson AKE, Dai Y, Nobis M, Baker MJ, McGhee EJ, Walker S, Schwarz JP, Kadir S, Morton JP, Myant KB, Huels DJ, Segonds-Pichon A, Sansom OJ, Anderson KI, Timpson P, Welch HCE. The Rac-FRET mouse reveals tight spatiotemporal control of Rac activity in primary cells and tissues. Cell Rep 2014; 6:1153-1164. [PMID: 24630994 PMCID: PMC3988842 DOI: 10.1016/j.celrep.2014.02.024] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2013] [Revised: 02/05/2014] [Accepted: 02/15/2014] [Indexed: 01/19/2023] Open
Abstract
The small G protein family Rac has numerous regulators that integrate extracellular signals into tight spatiotemporal maps of its activity to promote specific cell morphologies and responses. Here, we have generated a mouse strain, Rac-FRET, which ubiquitously expresses the Raichu-Rac biosensor. It enables FRET imaging and quantification of Rac activity in live tissues and primary cells without affecting cell properties and responses. We assessed Rac activity in chemotaxing Rac-FRET neutrophils and found enrichment in leading-edge protrusions and unexpected longitudinal shifts and oscillations during protruding and stalling phases of migration. We monitored Rac activity in normal or disease states of intestinal, liver, mammary, pancreatic, and skin tissue, in response to stimulation or inhibition and upon genetic manipulation of upstream regulators, revealing unexpected insights into Rac signaling during disease development. The Rac-FRET strain is a resource that promises to fundamentally advance our understanding of Rac-dependent responses in primary cells and native environments.
Collapse
Affiliation(s)
- Anna-Karin E Johnsson
- Signalling Programme, Babraham Institute, Babraham Research Campus, Cambridge CB22 3AT, UK
| | - Yanfeng Dai
- Signalling Programme, Babraham Institute, Babraham Research Campus, Cambridge CB22 3AT, UK
| | - Max Nobis
- Beatson Institute for Cancer Research, Switchback Road, Bearsden, Glasgow G61 1BD, UK
| | - Martin J Baker
- Signalling Programme, Babraham Institute, Babraham Research Campus, Cambridge CB22 3AT, UK
| | - Ewan J McGhee
- Beatson Institute for Cancer Research, Switchback Road, Bearsden, Glasgow G61 1BD, UK
| | - Simon Walker
- Signalling Programme, Babraham Institute, Babraham Research Campus, Cambridge CB22 3AT, UK
| | - Juliane P Schwarz
- Beatson Institute for Cancer Research, Switchback Road, Bearsden, Glasgow G61 1BD, UK
| | - Shereen Kadir
- Beatson Institute for Cancer Research, Switchback Road, Bearsden, Glasgow G61 1BD, UK
| | - Jennifer P Morton
- Beatson Institute for Cancer Research, Switchback Road, Bearsden, Glasgow G61 1BD, UK
| | - Kevin B Myant
- Beatson Institute for Cancer Research, Switchback Road, Bearsden, Glasgow G61 1BD, UK
| | - David J Huels
- Beatson Institute for Cancer Research, Switchback Road, Bearsden, Glasgow G61 1BD, UK
| | - Anne Segonds-Pichon
- Signalling Programme, Babraham Institute, Babraham Research Campus, Cambridge CB22 3AT, UK
| | - Owen J Sansom
- Beatson Institute for Cancer Research, Switchback Road, Bearsden, Glasgow G61 1BD, UK
| | - Kurt I Anderson
- Beatson Institute for Cancer Research, Switchback Road, Bearsden, Glasgow G61 1BD, UK
| | - Paul Timpson
- Beatson Institute for Cancer Research, Switchback Road, Bearsden, Glasgow G61 1BD, UK; Garvan Institute of Medical Research and Kinghorn Cancer Centre, Cancer Research Program, St. Vincent's Clinical School, Faculty of Medicine, University of New South Wales, NSW, 2010 Sydney, Australia.
| | - Heidi C E Welch
- Signalling Programme, Babraham Institute, Babraham Research Campus, Cambridge CB22 3AT, UK.
| |
Collapse
|
7
|
Broussard JA, Rappaz B, Webb DJ, Brown CM. Fluorescence resonance energy transfer microscopy as demonstrated by measuring the activation of the serine/threonine kinase Akt. Nat Protoc 2013; 8:265-81. [PMID: 23306460 DOI: 10.1038/nprot.2012.147] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
This protocol describes procedures for performing fluorescence resonance energy transfer (FRET) microscopy analysis by three different methods: acceptor photobleaching, sensitized emission and spectral imaging. We also discuss anisotropy and fluorescence lifetime imaging microscopy-based FRET techniques. By using the specific example of the FRET probe Akind (Akt indicator), which is a version of Akt modified such that FRET occurs when the probe is activated by phosphorylation, indicating Akt activation. The protocol provides a detailed step-by-step description of sample preparation, image acquisition and analysis, including control samples, image corrections and the generation of quantitative FRET/CFP ratio images for both sensitized emission and spectral imaging. The sample preparation takes 2 d, equipment setup takes 2-3 h and image acquisition and analysis take 6-8 h.
Collapse
Affiliation(s)
- Joshua A Broussard
- Department of Biological Sciences and Vanderbilt Kennedy Center for Research on Human Development, Vanderbilt University, Nashville, Tennessee, USA
| | | | | | | |
Collapse
|
8
|
Ai X, Niu L, Li Y, Yang F, Su X. A novel β-Cyclodextrin-QDs optical biosensor for the determination of amantadine and its application in cell imaging. Talanta 2012; 99:409-14. [DOI: 10.1016/j.talanta.2012.05.072] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2012] [Revised: 05/31/2012] [Accepted: 05/31/2012] [Indexed: 12/20/2022]
|
9
|
|
10
|
Why an A-loop phospho-mimetic fails to activate PAK1: understanding an inaccessible kinase state by molecular dynamics simulations. Structure 2010; 18:879-90. [PMID: 20637424 DOI: 10.1016/j.str.2010.04.011] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2010] [Revised: 03/30/2010] [Accepted: 04/16/2010] [Indexed: 11/21/2022]
Abstract
Crystal structures of inactive PAK1(K299R) and the activation (A)-loop phospho-mimetic PAK1(T423E) have suggested that the kinase domain is in an active state regardless of activation loop status. Contrary to a large body of literature, we find that neither is PAK1(T423E) active in cells, nor does it exhibit significant activity in vitro. To explain these discrepancies all-atom molecular dynamics (MD) simulations of PAK1(phospho-T423) in complex with ATP and substrate were performed. These simulations point to a key interaction between PAK1 Lys308, at the end of the alphaC helix, and the pThr423 phosphate group, not seen in X-ray structures. The orthologous PAK4 Arg359 fulfills the same role in immobilizing the alphaC helix. These in silico predictions were validated by experimental mutagenesis of PAK1 and PAK4. The simulations explain why the PAK1 A-loop phospho-mimetic is inactive, but also point to a key functional interaction likely found in other protein kinases.
Collapse
|
11
|
Sabouri-Ghomi M, Wu Y, Hahn K, Danuser G. Visualizing and quantifying adhesive signals. Curr Opin Cell Biol 2008; 20:541-50. [PMID: 18586481 PMCID: PMC2661108 DOI: 10.1016/j.ceb.2008.05.004] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2008] [Revised: 05/15/2008] [Accepted: 05/19/2008] [Indexed: 12/17/2022]
Abstract
Understanding the structural adaptation and signaling of adhesion sites in response to mechanical stimuli requires in situ characterization of the dynamic activation of a large number of adhesion components. Here, we review high-resolution live cell imaging approaches to measure forces, assembly, and interaction of adhesion components, and the activation of adhesion-mediated signals. We conclude by outlining computational multiplexing as a framework for the integration of these data into comprehensive models of adhesion signaling pathways.
Collapse
Affiliation(s)
- Mohsen Sabouri-Ghomi
- Department of Cell Biology, The Scripps Research Institute, 10550 N. Torrey Pines Road, La Jolla, CA 92037 USA
| | - Yi Wu
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599 USA
| | - Klaus Hahn
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599 USA
| | - Gaudenz Danuser
- Department of Cell Biology, The Scripps Research Institute, 10550 N. Torrey Pines Road, La Jolla, CA 92037 USA
| |
Collapse
|
12
|
Liu L, Wei G, Liu Z, He Z, Xiao S, Wang Q. Two-Photon Excitation Fluorescence Resonance Energy Transfer with Small Organic Molecule as Energy Donor for Bioassay. Bioconjug Chem 2008; 19:574-9. [DOI: 10.1021/bc700369q] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Lingzhi Liu
- College of Chemistry and Molecular Sciences and Key Laboratory of Acoustic and Photonic Materials and Devices of Ministry of Education, Wuhan University, Wuhan 430072, P. R. China
| | - Genghui Wei
- College of Chemistry and Molecular Sciences and Key Laboratory of Acoustic and Photonic Materials and Devices of Ministry of Education, Wuhan University, Wuhan 430072, P. R. China
| | - Zhihong Liu
- College of Chemistry and Molecular Sciences and Key Laboratory of Acoustic and Photonic Materials and Devices of Ministry of Education, Wuhan University, Wuhan 430072, P. R. China
| | - Zhike He
- College of Chemistry and Molecular Sciences and Key Laboratory of Acoustic and Photonic Materials and Devices of Ministry of Education, Wuhan University, Wuhan 430072, P. R. China
| | - Si Xiao
- College of Chemistry and Molecular Sciences and Key Laboratory of Acoustic and Photonic Materials and Devices of Ministry of Education, Wuhan University, Wuhan 430072, P. R. China
| | - Ququan Wang
- College of Chemistry and Molecular Sciences and Key Laboratory of Acoustic and Photonic Materials and Devices of Ministry of Education, Wuhan University, Wuhan 430072, P. R. China
| |
Collapse
|
13
|
Grailhe R, Merola F, Ridard J, Couvignou S, Le Poupon C, Changeux JP, Laguitton-Pasquier H. Monitoring protein interactions in the living cell through the fluorescence decays of the cyan fluorescent protein. Chemphyschem 2007; 7:1442-54. [PMID: 16739159 DOI: 10.1002/cphc.200600057] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Using fluorescence lifetime microspectroscopy and imaging techniques, we have studied the fluorescence of cyan fluorescent protein (CFP) transiently expressed in HEK-293 cells, in the presence or absence of its fluorescence resonance energy transfer (FRET) partner, yellow fluorescent protein (YFP). When the two proteins are attached through a 27-amino-acid linker, a 33 % average efficiency of intramolecular energy transfer is accurately determined inside the cell. Additionally, we observe a systematic quenching of the CFP fluorescence with increasing levels of protein expression. This quenching cannot be accounted for by formation of the previously described dimer of GFP-related proteins, since its magnitude is unchanged when the fluorescent proteins carry the mutation A206K shown to dissociate this dimer in vitro. Even when the intracellular protein concentration largely exceeds the in vitro dissociation constant of the dimer, self-association remains undetectable, either between free proteins or intramolecularly within the CFP-YFP construct. Instead, the detailed concentration effects are satisfactorily accounted for by a model of intermolecular, concentration-dependent energy transfer, arising from molecular proximity and crowding. In the case of CFP alone, we suggest that self-quenching could result from a pseudo-homo FRET mechanism between different, spectrally shifted emissive forms of the protein. These phenomena require careful consideration in intracellular FRET studies.
Collapse
Affiliation(s)
- Regis Grailhe
- Institut Pasteur, Laboratoire Recepteurs et Cognition, 25 rue du Dr. Roux, F-75015 Paris, France.
| | | | | | | | | | | | | |
Collapse
|
14
|
Goryachev AB, Pokhilko AV. Computational model explains high activity and rapid cycling of Rho GTPases within protein complexes. PLoS Comput Biol 2006; 2:e172. [PMID: 17140284 PMCID: PMC1676031 DOI: 10.1371/journal.pcbi.0020172] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2006] [Accepted: 10/09/2006] [Indexed: 01/01/2023] Open
Abstract
Formation of multiprotein complexes on cellular membranes is critically dependent on the cyclic activation of small GTPases. FRAP-based analyses demonstrate that within protein complexes, some small GTPases cycle nearly three orders of magnitude faster than they would spontaneously cycle in vitro. At the same time, experiments report concomitant excess of the activated, GTP-bound form of GTPases over their inactive form. Intuitively, high activity and rapid turnover are contradictory requirements. How the cells manage to maximize both remains poorly understood. Here, using GTPases of the Rab and Rho families as a prototype, we introduce a computational model of the GTPase cycle. We quantitatively investigate several plausible layouts of the cycling control module that consist of GEFs, GAPs, and GTPase effectors. We explain the existing experimental data and predict how the cycling of GTPases is controlled by the regulatory proteins in vivo. Our model explains distinct and separable roles that the activating GEFs and deactivating GAPs play in the GTPase cycling control. While the activity of GTPase is mainly defined by GEF, the turnover rate is a sole function of GAP. Maximization of the GTPase activity and turnover rate places conflicting requirements on the concentration of GAP. Therefore, to achieve a high activity and turnover rate at once, cells must carefully maintain concentrations of GEFs and GAPs within the optimal range. The values of these optimal concentrations indicate that efficient cycling can be achieved only within dense protein complexes typically assembled on the membrane surfaces. We show that the concentration requirement for GEF can be dramatically reduced by a GEF-activating GTPase effector that can also significantly boost the cycling efficiency. Interestingly, we find that the cycling regimes are only weakly dependent on the concentration of GTPase itself. A large variety of cellular processes, such as the formation of filopodia or transport vesicles, require that large protein complexes are precisely positioned on intracellular membranes to execute a specific task and then are promptly disassembled to perform their function elsewhere. Small GTPases play a major role in the spatiotemporal control of these complexes. Their function is based on the unique property of cycling between the active GTP-bound state, in which they enable complex formation, and the inactive GDP-bound state, which promotes complex dissolution. Recent experiments based on fluorescence recovery after photobleaching have found that some small GTPases rapidly cycle within protein complexes, causing continuous release and recruitment of the complex components. The seemingly futile cycling is accompanied by a large excess of the active form. This puzzling behavior challenges one's intuition and calls for the application of quantitative methods. Here, Goryachev and Pokhilko use computational modeling to identify regulatory mechanisms that could enable GTPases to cycle with the experimentally observed frequency and efficiency. They show that to achieve high activity and turnover simultaneously, the concentrations of the regulatory molecules that control GTPase cycling should be tightly maintained within the optimal range.
Collapse
|
15
|
Kurokawa K, Nakamura T, Aoki K, Matsuda M. Mechanism and role of localized activation of Rho-family GTPases in growth factor-stimulated fibroblasts and neuronal cells. Biochem Soc Trans 2005; 33:631-4. [PMID: 16042560 DOI: 10.1042/bst0330631] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Rho-family GTPases regulate various aspects of cell function by controlling cytoskeletal changes; however, their spatial regulation within the cells remains largely unknown. To understand this regulation, we have studied the spatiotemporal activity of Rho-family GTPases in migrating cells and growth factor-stimulated cells by using probes based on the principle of fluorescence resonance energy transfer. In migrating fibroblasts and epithelial cells, the level of RhoA activity is high both at the contractile tail and at the leading edge, whereas Rac1 and Cdc42 activities are high only at the leading edge. In cells stimulated with epidermal growth factor or nerve growth factor, activities of Rac1 and Cdc42 were transiently elevated in a broad area of the plasma membrane, followed by a localized activation at nascent lamellipodia. In contrast, on epidermal growth factor stimulation, RhoA activity decreased diffusely at the plasma membrane. Notably, RhoA activity persisted at the tip of growth factor-induced membrane ruffles and, in agreement with this finding, RhoA is required for membrane ruffling. These observations suggest that the activities of Rho-family GTPases are elaborately regulated in a time- and space-dependent manner to control cytoskeletal changes and that the basic mechanism of controlling cell shape via Rho-family GTPases is common to various cell types.
Collapse
Affiliation(s)
- K Kurokawa
- Department of Tumor Virology, Research Institute for Microbial Diseases, Osaka University, Yamadaoka, Suita-shi, Osaka 565-0871, Japan
| | | | | | | |
Collapse
|
16
|
Piekny A, Werner M, Glotzer M. Cytokinesis: welcome to the Rho zone. Trends Cell Biol 2005; 15:651-8. [PMID: 16243528 DOI: 10.1016/j.tcb.2005.10.006] [Citation(s) in RCA: 276] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2005] [Revised: 09/29/2005] [Accepted: 10/06/2005] [Indexed: 11/25/2022]
Abstract
Cytokinesis follows nuclear division and generates two distinct daughter cells, each replete with a full complement of the genome and cytoplasmic organelles. Members of the Rho family of GTPases are crucial regulators of this process in a wide variety of species. In many cell types, cytokinesis is mediated by a discretely localized contractile ring that is rich in actin and myosin. In this article (which is part of the Cytokinesis series), we review recent studies in animal cells that have shown that local assembly of the contractile ring is mediated by a discrete pool of GTP-bound, active RhoA. Advances in detecting the active pool of RhoA have allowed insights into the mechanisms and the molecules that promote the accumulation of active RhoA at the correct time and place in the cell.
Collapse
Affiliation(s)
- Alisa Piekny
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL 60637, USA
| | | | | |
Collapse
|
17
|
Collinson AD, Bligh SWA, Graham DL, Mott HR, Chalk PA, Korniotis N, Lowe PN. Fluorescence properties of green fluorescent protein FRET pairs concatenated with the small G protein, Rac, and its interacting domain of the kinase, p21-activated kinase. Assay Drug Dev Technol 2005; 2:659-73. [PMID: 15674024 DOI: 10.1089/adt.2004.2.659] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Many diseases are caused by aberrant cell signalling controlled by intracellular protein-protein interactions. Inhibitors of such interactions thus have enormous potential as chemotherapeutic agents. It is advantageous to test for such inhibitors using cell-based screens in which modulation of the interaction gives a rapid response. Fluorescence resonance energy transfer (FRET) systems, based on interacting donor and acceptor green fluorescent proteins (GFPs), have potential in such screens. Here, we describe experiments aimed at using a FRET system to monitor the interaction between the small G protein Rac and a region of its binding partner, the Ser/Thr kinase, p21-activated kinase (PAK). Initial attempts to use a previously described construct, enhanced GFP-PAK-enhanced blue fluorescent protein, failed because of the difficulty of obtaining equal and high expression levels of both the fusion protein and Rac in mammalian cells. Here, three proteins in which Rac, PAK, and the two GFPs were concatenated in different combinations on a single protein were expressed and characterised. In each construct, however, intramolecular interaction of PAK and Rac was observed. As this was of extremely high affinity, presumably because of entropy effects from the interacting partners being tethered, these molecules were not suitable for detection of inhibitors of the interaction. Molecular modelling was used to investigate the way in which the concatenated constructs might form intramolecular interactions. As this explained key properties of these proteins, it is likely that this approach could be used to design constructs where the unwanted intramolecular protein-protein interactions are prevented, whilst allowing the desired intermolecular Rac/PAK interaction. This would provide constructs that are useable for drug discovery.
Collapse
Affiliation(s)
- Andie D Collinson
- Structural & Biophysical Sciences, GlaxoSmithKline Medicines Research Centre, Stevenage, Herts, UK
| | | | | | | | | | | | | |
Collapse
|
18
|
Zhao ZS, Manser E. PAK and other Rho-associated kinases--effectors with surprisingly diverse mechanisms of regulation. Biochem J 2005; 386:201-14. [PMID: 15548136 PMCID: PMC1134783 DOI: 10.1042/bj20041638] [Citation(s) in RCA: 201] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2004] [Revised: 11/09/2004] [Accepted: 11/17/2004] [Indexed: 11/17/2022]
Abstract
The Rho GTPases are a family of molecular switches that are critical regulators of signal transduction pathways in eukaryotic cells. They are known principally for their role in regulating the cytoskeleton, and do so by recruiting a variety of downstream effector proteins. Kinases form an important class of Rho effector, and part of the biological complexity brought about by switching on a single GTPase results from downstream phosphorylation cascades. Here we focus on our current understanding of the way in which different Rho-associated serine/threonine kinases, denoted PAK (p21-activated kinase), MLK (mixed-lineage kinase), ROK (Rho-kinase), MRCK (myotonin-related Cdc42-binding kinase), CRIK (citron kinase) and PKN (protein kinase novel), interact with and are regulated by their partner GTPases. All of these kinases have in common an ability to dimerize, and in most cases interact with a variety of other proteins that are important for their function. A diversity of known structures underpin the Rho GTPase-kinase interaction, but only in the case of PAK do we have a good molecular understanding of kinase regulation. The ability of Rho GTPases to co-ordinate spatial and temporal phosphorylation events explains in part their prominent role in eukaryotic cell biology.
Collapse
Key Words
- cdc42
- mlk (mixed-lineage kinase)
- pak (p21-activated kinase)
- rac
- rho
- rok (rho-kinase)
- acc, anti-parallel coiled-coil
- crib, cdc42 and rac interactive binding
- crik, citron kinase
- crmp, collapsin response mediator protein
- dmpk, myotonic dystrophy kinase
- gef, guanine nucleotide exchange factor
- git1, g-protein-coupled receptor kinase-interacting target 1
- hsp90, heat shock protein 90
- jnk, c-jun n-terminal kinase
- ki, kinase inhibitory
- kim, ki motif
- limk, lim domain kinase
- mapk, mitogen-activated protein kinase
- mbs, myosin-binding subunit
- mekk, mapk/erk (extracellular-signal-regulated kinase) kinase kinase
- mkk, mapk kinase
- mlk, mixed-lineage kinase
- mrck, myotonin-related cdc42-binding kinase
- pak, p21-activated kinase
- pbd, p21-binding domain
- pdk1, 3-phosphoinositide-dependent kinase 1
- ph, pleckstrin homology
- pix, pak-interacting exchange factor
- pkc, protein kinase c
- pkn, protein kinase novel
- pp1, protein phosphatase type 1
- r-mlc, regulatory myosin light chain
- rok, rho-kinase
- sh3, src homology 3
Collapse
Affiliation(s)
- Zhou-shen Zhao
- GSK-IMCB Laboratory, Institute of Molecular and Cell Biology, Proteos Building, 61 Biopolis Drive, Singapore 138673
| | - Ed Manser
- GSK-IMCB Laboratory, Institute of Molecular and Cell Biology, Proteos Building, 61 Biopolis Drive, Singapore 138673
| |
Collapse
|
19
|
Braun DC, Garfield SH, Blumberg PM. Analysis by Fluorescence Resonance Energy Transfer of the Interaction between Ligands and Protein Kinase Cδ in the Intact Cell. J Biol Chem 2005; 280:8164-71. [PMID: 15611119 DOI: 10.1074/jbc.m413896200] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The role of the protein kinase C (PKC) family of serine/threonine kinases in cellular differentiation, proliferation, apoptosis, and other responses makes them attractive therapeutic targets. The activation of PKCs by ligands in vivo varies depending upon cell type; therefore, methods are needed to screen the potency of PKCs in this context. Here we describe a genetically encoded chimera of native PKCdelta fused to yellow- and cyan-shifted green fluorescent protein, which can be expressed in mammalian cells. This chimeric protein kinase, CY-PKCdelta, retains native or near-native activity in the several biological and biochemical parameters that we tested. Binding assays showed that CY-PKCdelta and native human PKCdelta have similar binding affinity for phorbol 12,13-dibutyrate. Analysis of translocation by Western blotting and confocal microscopy showed that CY-PKCdelta translocates from the cytosol to the membrane upon treatment with ligand, that the translocation has similar dose dependence as that of endogenous PKCdelta, and that the pattern of translocation is indistinguishable from that of the green fluorescent protein-PKCdelta fusion well characterized from earlier studies. Treatment with phorbol ester of cells expressing CY-PKCdelta resulted in a dose-dependent increase in FRET that could be visualized in situ by confocal microscopy or measured fluorometrically. By using this construct, we were able to measure the kinetics and potencies of 12 known PKC ligands, with respect to CY-PKCdelta, in the intact cell. The CY-PKCdelta chimera and the in vivo assays described here therefore show potential for high throughput screening of prospective PKCdelta ligands within the context of cell type.
Collapse
Affiliation(s)
- Derek C Braun
- Department of Biology, Gallaudet University, Washington, D. C. 20002, USA
| | | | | |
Collapse
|
20
|
Bunt G, Wouters FS. Visualization of Molecular Activities Inside Living Cells with Fluorescent Labels. INTERNATIONAL REVIEW OF CYTOLOGY 2004; 237:205-77. [PMID: 15380669 DOI: 10.1016/s0074-7696(04)37005-1] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/09/2022]
Abstract
The major task of modern cell biology is to identify the function and relation of the many different gene products, discovered by genomics and proteomics approaches, in the context of the living cell. To achieve this goal, an increasing toolbox of custom-designed biosensors based on fluorescent labels is available to study the molecular activities of the cellular machinery. An overview of the current status of the young field of molecular-cellular physiology is presented that includes the application of fluorescent labels in the design of biosensors and the major detection schemes used to extract their sensing information. In particular, the use of the photophysical phenomenon of Förster resonance energy transfer (FRET) as a powerful indicator of cellular biochemical events is discussed. In addition, we will point out the challenges and directions of the field and project the short-term future for the application of fluorescence-based biosensors in biology.
Collapse
Affiliation(s)
- Gertrude Bunt
- Max-Planck-Institute for Experimental Medicine, Molecular Biology of Neuronal Signals, Göttingen, Germany
| | | |
Collapse
|
21
|
Majoul I. Analysing the action of bacterial toxins in living cells with fluorescence resonance energy transfer (FRET). Int J Med Microbiol 2004; 293:495-503. [PMID: 15149024 DOI: 10.1078/1438-4221-00307] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Bacterial toxins represent small molecules produced by microorganisms. Different toxins act on specific target molecules in mammalian cells. Once discovered, bacterial toxins have been providing tools to study cellular functions and often helped the dissection of complex cellular pathways, e.g. endocytic or secretory trafficking or signal transduction, by virtue of the fact that they either block or activate their specific cellular target molecules. Purified bacterial toxins have also allowed to address many basic biological questions and have provided tools for in vitro and in vivo experimental approaches in many fields of modern biology. The understanding of how bacterial toxins act in living cells often depends on our ability to visualize the trafficking and signaling pathways of these molecules. Fluorescence microscopy and other imaging tools are essential to provide insights into the functional changes induced by these pathogens at the level of individual host cells or single target proteins. Inside a single cell we can measure and quantify the effects of bacterial toxins on specific cellular proteins by microscopic and spectroscopic techniques. Fluorescence resonance energy transfer (FRET) is a high-resolution technique that allows to study protein-protein interactions. FRET can provide distance information in the range of 3- 7 nm between fluorescently labeled bacterial proteins in the live cell and cellular target proteins expressed as chimeras with green fluorescent protein (GFP), or spectrally shifted variants thereof. The purpose of this review is to introduce readers to the main experimental setups for analyses of protein-protein interactions using FRET as well as some applications.
Collapse
Affiliation(s)
- Irina Majoul
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, UK.
| |
Collapse
|
22
|
Abstract
Fluorescence resonance energy transfer (FRET) is a technique used to measure the interaction between two molecules labeled with two different fluorophores (the donor and the acceptor) by the transfer of energy from the excited donor to the acceptor. In biological applications, this technique has become popular to qualitatively map protein-protein interactions, and in biophysical projects it is used as a quantitative measure for distances between a single donor and acceptor molecule. Numerous approaches can be found in the literature to quantify and map FRET, but the measures they provide are often difficult to interpret. We propose here a quantitative comparison of these methods by using a surface FRET system with controlled amounts of donor and acceptor fluorophores and controlled distances between them. We support the system with a Monte Carlo simulation of FRET, which provides reference values for the FRET efficiency under various experimental conditions. We validate a representative set of FRET efficiencies and indices calculated from the different methods with different experimental settings. Finally, we test their sensitivity and draw conclusions for the preparation of FRET experiments in more complex and less-controlled systems.
Collapse
Affiliation(s)
- Claude Berney
- BioMicroMetrics Group, Laboratory for Biomechanics, Swiss Federal Institute of Technology, CH-8952 Schlieren, Switzerland.
| | | |
Collapse
|
23
|
Ventre I, Ledgham F, Prima V, Lazdunski A, Foglino M, Sturgis JN. Dimerization of the quorum sensing regulator RhlR: development of a method using EGFP fluorescence anisotropy. Mol Microbiol 2003; 48:187-98. [PMID: 12657054 DOI: 10.1046/j.1365-2958.2003.03422.x] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Of considerable interest in the biology of pathogenic bacteria are the mechanisms of intercellular signalling that can lead to the formation of persistent infections. In this article, we have examined the intracellular behaviour of a Pseudomonas aeruginosa quorum sensing regulator RhlR believed to be important in this process. We have further examined the modulation of this behaviour in response to various auto-inducers. For these measurements, we have developed an assay based on the fluorescence anisotropy of EGFP fusion proteins that we use to measure protein-protein interactions in vivo. We show that the transcriptional regulator, RhlR, expressed as an EGFP fusion protein in Escherichia coli, forms a homodimer. This homodimer can be dissociated into monomers by the auto-inducer N-(3-oxododecanoyl)-l-homoserine lactone (3O-C12-HSL) whereas N-(butanoyl)-l-homoserine lactone (C4-HSL) has little effect. These observations are of particular interest as RhlR modulation of gene expression depends on the presence of C4-HSL, whereas 3O-C12-HSL modulates the expression of genes regulated by LasR. These observations thus provide a framework for understanding the regulatory network that links the various different QS regulators in P. aeruginosa. Furthermore, the technique we have developed should permit the study of numerous protein/protein or protein/nucleic acid interactions in vivo and so shed light on natural protein function.
Collapse
Affiliation(s)
- Isabelle Ventre
- Laboratoire d'Ingéniérie des Systèmes Macromoléculaires, UPR9027, IBSM/CNRS, 31 Chemin Joseph Aiguier, 13402 Marseille Cedex 20, France
| | | | | | | | | | | |
Collapse
|
24
|
Gaits F, Hahn K. Shedding light on cell signaling: interpretation of FRET biosensors. SCIENCE'S STKE : SIGNAL TRANSDUCTION KNOWLEDGE ENVIRONMENT 2003; 2003:PE3. [PMID: 12527820 DOI: 10.1126/stke.2003.165.pe3] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
This Perspective compares recently developed approaches for studying live-cell signaling dynamics. It is now possible not only to study the changing localizations of proteins within living cells but to correlate these dynamics with quantitation of protein activities, including ligand interactions and phosphorylation. Initial applications of an increasingly varied toolchest of techniques have revealed strengths and weaknesses in each approach, clarifying which tool is best for which job.
Collapse
Affiliation(s)
- Frédérique Gaits
- Department of Cell Biology, Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
| | | |
Collapse
|
25
|
Abstract
Many different signaling pathways are involved in deregulation of cell proliferation leading to cancer. Although genomic approaches successfully identified a great variety of molecules associated with cancerogenesis, other strategies must be applied to elucidate complex interactions between these molecules. One promising approach is fluorescence resonance energy transfer, a proximity-dependent fluorescence phenomenon. With the development of spectrally different fluorescent proteins and improved technologies for fluorescence measurements, this approach gains an enormous potential for future research. The fluorescence resonance energy transfer principle can be applied for studying all kinds of interactions or conformational changes, and it can also be used for microscopic visualization and subcellular localization of biochemical reactions, thereby promoting the progress of cancer research. Moreover, it can be exploited to develop sensitive and efficient drug screening systems and to design valuable diagnostic tools.
Collapse
Affiliation(s)
- Johannes A Schmid
- Department of Vascular Biology and Thrombosis Research, University of Vienna, Austria.
| | | |
Collapse
|
26
|
Itoh RE, Kurokawa K, Ohba Y, Yoshizaki H, Mochizuki N, Matsuda M. Activation of rac and cdc42 video imaged by fluorescent resonance energy transfer-based single-molecule probes in the membrane of living cells. Mol Cell Biol 2002; 22:6582-91. [PMID: 12192056 PMCID: PMC135619 DOI: 10.1128/mcb.22.18.6582-6591.2002] [Citation(s) in RCA: 447] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2002] [Revised: 03/18/2002] [Accepted: 06/20/2002] [Indexed: 01/13/2023] Open
Abstract
Rho family G proteins, including Rac and Cdc42, regulate a variety of cellular functions such as morphology, motility, and gene expression. We developed fluorescent resonance energy transfer-based probes which monitored the local balance between the activities of guanine nucleotide exchange factors and GTPase-activating proteins for Rac1 and Cdc42 at the membrane. These probes, named Raichu-Rac and Raichu-Cdc42, consisted of a Cdc42- and Rac-binding domain of Pak, Rac1 or Cdc42, a pair of green fluorescent protein mutants, and a CAAX box of Ki-Ras. With these probes, we video imaged the Rac and Cdc42 activities. In motile HT1080 cells, activities of both Rac and Cdc42 gradually increased toward the leading edge and decreased rapidly when cells changed direction. Under a higher magnification, we observed that Rac activity was highest immediately behind the leading edge, whereas Cdc42 activity was most prominent at the tip of the leading edge. Raichu-Rac and Raichu-Cdc42 were also applied to a rapid and simple assay for the analysis of putative guanine nucleotide exchange factors (GEFs) and GTPase-activating proteins (GAPs) in living cells. Among six putative GEFs and GAPs, we identified KIAA0362/DBS as a GEF for Rac and Cdc42, KIAA1256 as a GEF for Cdc42, KIAA0053 as a GAP for Rac and Cdc42, and KIAA1204 as a GAP for Cdc42. In conclusion, use of these single-molecule probes to determine Rac and Cdc42 activity will accelerate the analysis of the spatiotemporal regulation of Rac and Cdc42 in a living cell.
Collapse
Affiliation(s)
- Reina E Itoh
- Department of Tumor Virology, Research Institute for Microbial Diseases, Osaka University, CREST, Japan
| | | | | | | | | | | |
Collapse
|