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Graziano BR, Town JP, Sitarska E, Nagy TL, Fošnarič M, Penič S, Iglič A, Kralj-Iglič V, Gov NS, Diz-Muñoz A, Weiner OD. Cell confinement reveals a branched-actin independent circuit for neutrophil polarity. PLoS Biol 2019; 17:e3000457. [PMID: 31600188 PMCID: PMC6805013 DOI: 10.1371/journal.pbio.3000457] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Revised: 10/22/2019] [Accepted: 09/16/2019] [Indexed: 12/30/2022] Open
Abstract
Migratory cells use distinct motility modes to navigate different microenvironments, but it is unclear whether these modes rely on the same core set of polarity components. To investigate this, we disrupted actin-related protein 2/3 (Arp2/3) and the WASP-family verprolin homologous protein (WAVE) complex, which assemble branched actin networks that are essential for neutrophil polarity and motility in standard adherent conditions. Surprisingly, confinement rescues polarity and movement of neutrophils lacking these components, revealing a processive bleb-based protrusion program that is mechanistically distinct from the branched actin-based protrusion program but shares some of the same core components and underlying molecular logic. We further find that the restriction of protrusion growth to one site does not always respond to membrane tension directly, as previously thought, but may rely on closely linked properties such as local membrane curvature. Our work reveals a hidden circuit for neutrophil polarity and indicates that cells have distinct molecular mechanisms for polarization that dominate in different microenvironments. Cells display a high degree of plasticity in migration, but how polarity is organized in different microenvironments has remained unclear. This study uses mechanical perturbations to reveal that migration using actin-rich or bleb-based protrusions are both organized around Rac GTPase.
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Affiliation(s)
- Brian R. Graziano
- Cardiovascular Research Institute and Department of Biochemistry and Biophysics, University of California, San Francisco, California, United States of America
| | - Jason P. Town
- Cardiovascular Research Institute and Department of Biochemistry and Biophysics, University of California, San Francisco, California, United States of America
| | - Ewa Sitarska
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Tamas L. Nagy
- Cardiovascular Research Institute and Department of Biochemistry and Biophysics, University of California, San Francisco, California, United States of America
| | - Miha Fošnarič
- Laboratory of Clinical Biophysics, Faculty of Medicine, University of Ljubljana, Slovenia
| | - Samo Penič
- Department of Theoretical Electrotechnics, Mathematics and Physics, Faculty of Electrical Engineering, University of Ljubljana, Slovenia
| | - Aleš Iglič
- Laboratory of Clinical Biophysics, Faculty of Medicine, University of Ljubljana, Slovenia
- Department of Theoretical Electrotechnics, Mathematics and Physics, Faculty of Electrical Engineering, University of Ljubljana, Slovenia
| | | | - Nir S. Gov
- Department of Chemical and Biological Physics, Weizmann Institute, Rehovot, Israel
| | - Alba Diz-Muñoz
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Orion D. Weiner
- Cardiovascular Research Institute and Department of Biochemistry and Biophysics, University of California, San Francisco, California, United States of America
- * E-mail:
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Bell GRR, Natwick DE, Collins SR. Parallel High-Resolution Imaging of Leukocyte Chemotaxis Under Agarose with Rho-Family GTPase Biosensors. Methods Mol Biol 2018; 1821:71-85. [PMID: 30062406 DOI: 10.1007/978-1-4939-8612-5_6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Neutrophils are key early responders in the innate immune response that use chemotaxis, the directed migration along chemical gradients, to reach sites of infection or inflammation. This process requires integrating inputs from cell surface receptors with the cell's polarity and motility signaling network, in which highly dynamic and interconnected signaling by Rho-family GTPases plays a central role. To understand this fundamentally important behavior, we describe a high-resolution, under-agarose chemotaxis assay for use with neutrophil-like cell lines (HL-60 or PLB-985) or with primary neutrophils. We also describe how to use optical uncaging of chemoattractants to stimulate cells in this assay. These techniques are compatible with epifluorescence, total internal reflection fluorescence (TIRF), and confocal microscopy. Additionally, we cover how to measure the activities of Rho-family GTPases in this context using Förster resonance energy transfer (FRET)-based biosensors. The specific experimental steps outlined in this chapter include how to (1) set up the under-agarose assay, (2) optically pattern chemoattractant gradients, (3) image cells, and (4) conduct basic image analysis for FRET biosensors.
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Affiliation(s)
- George R R Bell
- Department of Microbiology and Molecular Genetics, University of California, Davis, Davis, CA, USA
| | - Dean E Natwick
- Department of Microbiology and Molecular Genetics, University of California, Davis, Davis, CA, USA
| | - Sean R Collins
- Department of Microbiology and Molecular Genetics, University of California, Davis, Davis, CA, USA.
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3
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Yang HW, Collins SR, Meyer T. Locally excitable Cdc42 signals steer cells during chemotaxis. Nat Cell Biol 2015; 18:191-201. [PMID: 26689677 PMCID: PMC5015690 DOI: 10.1038/ncb3292] [Citation(s) in RCA: 124] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Accepted: 11/23/2015] [Indexed: 12/14/2022]
Abstract
Neutrophils and other amoeboid cells chemotax by steering their front towards chemoattractant. While Ras, Rac, Cdc42, and RhoA small GTPases all regulate chemotaxis, it has been unclear how they spatiotemporally control polarization and steering. Using fluorescence biosensors in neutrophil-like PLB-985 cells and photorelease of chemoattractant, we show that local Cdc42 signals, but not those of Rac, RhoA or Ras, precede cell turning during chemotaxis. Furthermore, preexisting local Cdc42 signals in morphologically unpolarized cells predict the future direction of movement upon uniform stimulation. Moreover, inhibition of actin polymerization uncovers recurring local Cdc42 activity pulses, suggesting that Cdc42 has the excitable characteristic of the compass activity proposed in models of chemotaxis. Globally, Cdc42 antagonizes RhoA, and maintains a steep spatial activity gradient during migration, while Ras and Rac form shallow gradients. Thus, chemotactic steering and de novo polarization are both directed by locally excitable Cdc42 signals.
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Affiliation(s)
- Hee Won Yang
- Department of Chemical & Systems Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Sean R Collins
- Department of Chemical & Systems Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Tobias Meyer
- Department of Chemical & Systems Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
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Collins SR, Yang HW, Bonger KM, Guignet EG, Wandless TJ, Meyer T. Using light to shape chemical gradients for parallel and automated analysis of chemotaxis. Mol Syst Biol 2015; 11:804. [PMID: 25908733 PMCID: PMC4422560 DOI: 10.15252/msb.20156027] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2015] [Revised: 03/25/2015] [Accepted: 03/27/2015] [Indexed: 12/19/2022] Open
Abstract
Numerous molecular components have been identified that regulate the directed migration of eukaryotic cells toward sources of chemoattractant. However, how the components of this system are wired together to coordinate multiple aspects of the response, such as directionality, speed, and sensitivity to stimulus, remains poorly understood. Here we developed a method to shape chemoattractant gradients optically and analyze cellular chemotaxis responses of hundreds of living cells per well in 96-well format by measuring speed changes and directional accuracy. We then systematically characterized migration and chemotaxis phenotypes for 285 siRNA perturbations. A key finding was that the G-protein Giα subunit selectively controls the direction of migration while the receptor and Gβ subunit proportionally control both speed and direction. Furthermore, we demonstrate that neutrophils chemotax persistently in response to gradients of fMLF but only transiently in response to gradients of ATP. The method we introduce is applicable for diverse chemical cues and systematic perturbations, can be used to measure multiple cell migration and signaling parameters, and is compatible with low- and high-resolution fluorescence microscopy.
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Affiliation(s)
- Sean R Collins
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA, USA
| | - Hee Won Yang
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA, USA
| | - Kimberly M Bonger
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA, USA
| | - Emmanuel G Guignet
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA, USA
| | - Thomas J Wandless
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA, USA
| | - Tobias Meyer
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA, USA
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Markiewicz BN, Culik RM, Gai F. Tightening up the structure, lighting up the pathway: Application of molecular constraints and light to manipulate protein folding, self-assembly and function. Sci China Chem 2014; 57:1615-1624. [PMID: 25722715 PMCID: PMC4337807 DOI: 10.1007/s11426-014-5225-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Chemical cross-linking provides an effective avenue to reduce the conformational entropy of polypeptide chains and hence has become a popular method to induce or force structural formation in peptides and proteins. Recently, other types of molecular constraints, especially photoresponsive linkers and functional groups, have also found increased use in a wide variety of applications. Herein, we provide a concise review of using various forms of molecular strategies to constrain proteins, thereby stabilizing their native states, gaining insight into their folding mechanisms, and/or providing a handle to trigger a conformational process of interest with light. The applications discussed here cover a wide range of topics, ranging from delineating the details of the protein folding energy landscape to controlling protein assembly and function.
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Affiliation(s)
| | - Robert M. Culik
- Department of Biochemistry and Biophysics, University of Pennsylvania, PA, 19104, USA
| | - Feng Gai
- Department of Chemistry, University of Pennsylvania, PA, 19104, USA
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Miller DS, Chirayil S, Ball HL, Luebke KJ. Manipulating cell migration and proliferation with a light-activated polypeptide. Chembiochem 2009; 10:577-84. [PMID: 19165838 DOI: 10.1002/cbic.200800679] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Remote control of cells: A polypeptide has been made that stimulates proliferation and migration of cells upon photochemical activation. This light-activated polypeptide enables spatially defined control of cell populations at the scale of tissue organization; this is accomplished without physically contacting the cells or modifying their substrate. Polypeptide growth and differentiation factors modulate a wide variety of cell behaviors and can be used to manipulate cells in vitro for tissue engineering and basic studies of cell biology. To emulate in vitro the spatial aspect of growth factor function, new methods are needed to generate defined spatial gradients of activity. Polypeptide factors that are engineered to be activated with light provide a method for creating concentration gradients with the fine precision in space and time with which light can be directed. As a first test of this approach, we have chemically synthesized a polypeptide with the sequence of epidermal growth factor in which a critical glutamate is "caged" with a photoremovable group. Photolysis of this polypeptide afforded maximal mitogenic and chemokinetic activity at concentrations at which the caged factor was inactive. Spatially resolved photolysis of the factor resulted in spatial patterning of fibroblasts. This system will be useful for ex vivo tissue engineering and for investigating the interactions of cells with their matrix and the role of chemical gradients in biological pattern formation.
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Affiliation(s)
- Danielle S Miller
- Division of Translational Research, University of Texas Southwestern Medical Center, Dallas, TX 75390-9185, USA
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Abstract
A caged molecule is an inert but photosensitive molecule that is transformed by photolysis into a biologically active molecule at high speed (typically 1 msec). The process is referred to as photorelease. The spatial resolution of photorelease is limited by the properties of light; submicrometer resolution is potentially achievable. Therefore, focal photorelease of caged molecules enables one to control biological processes with high spatio-temporal precision. The principles underlying caged molecules as well as practical considerations for their use are discussed in this unit.
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Affiliation(s)
- Joseph P Y Kao
- University of Maryland Biotechnology Institute, Baltimore, Maryland, USA
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Abstract
Biologically active compounds which are light-responsive offer experimental possibilities which are otherwise very difficult to achieve. Since light can be manipulated very precisely, for example, with lasers and microscopes rapid jumps in concentration of the active form of molecules are possible with exact control of the area, time, and dosage. The development of such strategies started in the 1970s. This review summarizes new developments of the last five years and deals with "small molecules", proteins, and nucleic acids which can either be irreversibly activated with light (these compounds are referred to as "caged compounds") or reversibly switched between an active and an inactive state.
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Affiliation(s)
- Günter Mayer
- Kekulé-Institut für Organische Chemie und Biochemie, Rheinische Friedrich-Wilhelms-Universität Bonn, Gerhard-Domagk-Strasse 1, 53121 Bonn, Germany.
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Bourgault S, Létourneau M, Fournier A. Development of photolabile caged analogs of endothelin-1. Peptides 2007; 28:1074-82. [PMID: 17400333 DOI: 10.1016/j.peptides.2007.02.013] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/02/2006] [Revised: 02/17/2007] [Accepted: 02/23/2007] [Indexed: 10/23/2022]
Abstract
Photoactivable caged analogs of endothelin-1 (ET-1) were obtained after derivatization with the photolabile 4,5-dimethoxynitrobenzyl (DMNB) group. This was achieved by the incorporation of N-alpha-Fmoc caged building blocks of Lys, Asp, Glu and Tyr during the solid phase peptide synthesis step. The C-terminal carboxylic function was also derivatized. However, difficulties were encountered with the introduction of the Asp and Glu photoactivable building blocks. As a matter of fact, formation of an aminosuccinyl derivative, through cyclization of the Asp(ODMNB) residue, and the formation of a pyrrolidone ring from the Glu(ODMNB) residue were highly favored by the electronic properties of the photocleavable function. ET-1 analogs were also tested in the ET(A) and ET(B) paradigms and specific pharmacological profiles were obtained for each peptide.
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Affiliation(s)
- S Bourgault
- Laboratoire d'Etudes Moléculaires et Pharmacologiques des Peptides, INRS - Institut Armand-Frappier, Institut National de la Recherche Scientifique, 245 Boul. Hymus, Pointe-Claire, Que., Canada H9R 1G6.
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10
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Rathert P, Raskó T, Roth M, Slaska-Kiss K, Pingoud A, Kiss A, Jeltsch A. Reversible inactivation of the CG specific SssI DNA (cytosine-C5)-methyltransferase with a photocleavable protecting group. Chembiochem 2007; 8:202-7. [PMID: 17195251 DOI: 10.1002/cbic.200600358] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Caging of proteins by conjugation with a photocleavable group is a powerful approach for reversibly blocking enzymatic activity. Here we describe the covalent modification of the bacterial SssI DNA methyltransferase (M.SssI) with the cysteine-specific reagent 4,5-dimethoxy-2-nitrobenzylbromide (DMNBB). M.SssI contains two cysteine residues; replacement of the active-site Cys141 with Ser resulted in an approximately 100-fold loss of enzymatic activity; this indicates an important role for this residue in catalysis. However, replacement of Cys368 with Ala did not affect methyltransferase activity. Treatment of the Cys368Ala mutant enzyme with DMNBB led to an almost complete loss of activity. Irradiation of the inactivated enzyme with near-ultraviolet light (320-400 nm) restored 60 % of the catalytic activity. This indicates that caging by DMNBB can be used for the reversible inactivation of M.SssI.
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Affiliation(s)
- Philipp Rathert
- Biochemistry Laboratory International University Bremen, School of Engineering and Science, Campus Ring 1, 28759 Bremen, Germany
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12
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Affiliation(s)
- Christian Jäckel
- Free University Berlin, Department of Chemistry – Organic Chemistry Takustrasse 3, 14195 Berlin, Germany, Fax: +49‐30‐838‐55644
| | - Beate Koksch
- Free University Berlin, Department of Chemistry – Organic Chemistry Takustrasse 3, 14195 Berlin, Germany, Fax: +49‐30‐838‐55644
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Koksch B, Dahl C, Radics G, Vocks A, Arnold K, Arnhold J, Sieler J, Burger K. Fluoro-modified chemotactic peptides: fmlf analogues. J Pept Sci 2003; 10:67-81. [PMID: 14994985 DOI: 10.1002/psc.515] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
A small library of peptide analogues of the chemotactic tripeptide For-Met-Leu-Phe-NH2 modified by substitution of Leu at position 2 by three different fluorinated amino acids varying in content of fluorine, length of the fluorinated side chain, and alkylation degree at the alpha-carbon atom was synthesized. The influence of the fluorine substitution on the biological activity was investigated by measuring the oxidative activity of neutrophils using a luminol-dependent chemiluminescence assay.
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Affiliation(s)
- Beate Koksch
- Department of Organic Chemistry, University of Leipzig, 04103 Leipzig, Germany.
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Yeh RH, Yan X, Cammer M, Bresnick AR, Lawrence DS. Real time visualization of protein kinase activity in living cells. J Biol Chem 2002; 277:11527-32. [PMID: 11790790 DOI: 10.1074/jbc.m111300200] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
A library of fluorescently labeled protein kinase C (PKC) peptide substrates was prepared to identify a phosphorylation-induced reporter of protein kinase activity. The lead PKC substrate displays a 2.5-fold change in fluorescence intensity upon phosphorylation. PKC activity is readily sampled in cell lysates containing the activated PKCs. Immunodepletion of conventional PKCs from the cell lysate eliminates the fluorescence response, suggesting that this peptide substrate is selectively phosphorylated by PKCalpha, beta, and gamma. Finally, living cells microinjected with the peptide substrate exhibit a 2-fold increase in fluorescence intensity upon exposure to a PKC activator. These results suggest that peptide-based protein kinase biosensors may be useful in monitoring the temporal and spatial dynamics of PKC activity in living cells.
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Affiliation(s)
- Ren-Hwa Yeh
- Department of Biochemistry, The Albert Einstein College of Medicine of Yeshiva University, Bronx, New York 10461-1602, USA
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