1
|
Oppenheimer KG, Hager NA, McAtee CK, Filiztekin E, Shang C, Warnick JA, Bruchez MP, Brodsky JL, Prosser DC, Kwiatkowski AV, O'Donnell AF. Optimization of the fluorogen-activating protein tag for quantitative protein trafficking and colocalization studies in S. cerevisiae. Mol Biol Cell 2024; 35:mr5. [PMID: 38809589 DOI: 10.1091/mbc.e24-04-0174] [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] [Indexed: 05/30/2024] Open
Abstract
Spatial and temporal tracking of fluorescent proteins (FPs) in live cells permits visualization of proteome remodeling in response to extracellular cues. Historically, protein dynamics during trafficking have been visualized using constitutively active FPs fused to proteins of interest. While powerful, such FPs label all cellular pools of a protein, potentially masking the dynamics of select subpopulations. To help study protein subpopulations, bioconjugate tags, including the fluorogen activation proteins (FAPs), were developed. FAPs are comprised of two components: a single-chain antibody (SCA) fused to the protein of interest and a malachite-green (MG) derivative, which fluoresces only when bound to the SCA. Importantly, the MG derivatives can be either cell-permeant or -impermeant, thus permitting isolated detection of SCA-tagged proteins at the cell surface and facilitating quantitative endocytic measures. To expand FAP use in yeast, we optimized the SCA for yeast expression, created FAP-tagging plasmids, and generated FAP-tagged organelle markers. To demonstrate FAP efficacy, we coupled the SCA to the yeast G-protein coupled receptor Ste3. We measured Ste3 endocytic dynamics in response to pheromone and characterized cis- and trans-acting regulators of Ste3. Our work significantly expands FAP technology for varied applications in S. cerevisiae.
Collapse
Affiliation(s)
| | - Natalie A Hager
- Department of Biological Sciences, University of Pittsburgh, PA 15260
| | - Ceara K McAtee
- Department of Biological Sciences, University of Pittsburgh, PA 15260
| | - Elif Filiztekin
- Department of Biological Sciences, University of Pittsburgh, PA 15260
| | - Chaowei Shang
- Department of Biological Sciences, University of Pittsburgh, PA 15260
| | - Justina A Warnick
- Department of Biological Sciences, University of Pittsburgh, PA 15260
| | - Marcel P Bruchez
- Molecular Biosensor and Imaging Center, Carnegie Mellon University, Pittsburgh, PA 15213
| | - Jeffrey L Brodsky
- Department of Biological Sciences, University of Pittsburgh, PA 15260
| | - Derek C Prosser
- Department of Biology, Virginia Commonwealth University, Richmond, VA 23284
| | - Adam V Kwiatkowski
- Department of Cell Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA 15261
| | | |
Collapse
|
2
|
Deng Z, Li L, Jia H, Li NF, He J, Li MD, Phillips DL, Li Y. Insights into the Photodynamics of Fluorescence Emission and Singlet Oxygen Generation of Fluorogen Activating Protein-Malachite Green Systems. Chemistry 2023; 29:e202203684. [PMID: 36453719 DOI: 10.1002/chem.202203684] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Revised: 11/30/2022] [Accepted: 11/30/2022] [Indexed: 12/03/2022]
Abstract
The self-assembled fluorogen activating protein (FAP)-malachite green (MG) complex is a well-established protein-ligand system, which can realize binding-caused fluorescence turn-on of MG and singlet oxygen (1 O2 ) generation by MG iodination. To clarify the mechanism of fluorescence activation and 1 O2 generation, the photodynamics of different halogen-substituted MG derivatives and their corresponding FAP-MG complexes were studied by femtosecond transient absorption spectroscopy and theoretical computations. The results show that the rotation of MG is restricted by FAP binding, which prevents a rapid internal conversion to allow a longer lifetime for the excited MG to undergo fluorescence emission and intersystem crossing. Moreover, these FAP-MG complexes exhibit notably varied fluorescence quantum yields (ΦFL ) and 1 O2 yields. The study on the decay pathways indicates that such an anti-heavy atom effect predominately stems from the lifetimes of the excited-state species. The photodynamic mechanism study here will lead to more advanced FAP-MG systems with high spatiotemporal resolution.
Collapse
Affiliation(s)
- Ziqi Deng
- Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong, China
| | - Lan Li
- Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong, China
| | - Han Jia
- Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong, China
| | - Nga-Fong Li
- Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong, China
| | - Jiaxing He
- Department of Chemistry and Key Laboratory for Preparation and, Application of Ordered Structure Materials of Guangdong Providence, Shantou University, Shantou, 515063, Guangdong, China
| | - Ming-De Li
- Department of Chemistry and Key Laboratory for Preparation and, Application of Ordered Structure Materials of Guangdong Providence, Shantou University, Shantou, 515063, Guangdong, China
| | - David Lee Phillips
- Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong, China
| | - Ying Li
- Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong, China
| |
Collapse
|
3
|
Kang F, Xie L, Qin T, Miao Y, Kang Y, Takahashi T, Liang T, Xie H, Gaisano HY. Plasma membrane flipping of Syntaxin-2 regulates its inhibitory action on insulin granule exocytosis. Nat Commun 2022; 13:6512. [PMID: 36316316 PMCID: PMC9622911 DOI: 10.1038/s41467-022-33986-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Accepted: 10/05/2022] [Indexed: 11/07/2022] Open
Abstract
Enhancing pancreatic β-cell secretion is a primary therapeutic target for type-2 diabetes (T2D). Syntaxin-2 (Stx2) has just been identified to be an inhibitory SNARE for insulin granule exocytosis, holding potential as a treatment for T2D, yet its molecular underpinnings remain unclear. We show that excessive Stx2 recruitment to raft-like granule docking sites at higher binding affinity than pro-fusion syntaxin-1A effectively competes for and inhibits fusogenic SNARE machineries. Depletion of Stx2 in human β-cells improves insulin secretion by enhancing trans-SNARE complex assembly and cis-SNARE disassembly. Using a genetically-encoded reporter, glucose stimulation is shown to induce Stx2 flipping across the plasma membrane, which relieves its suppression of cytoplasmic fusogenic SNARE complexes to promote insulin secretion. Targeting the flipping efficiency of Stx2 profoundly modulates secretion, which could restore the impaired insulin secretion in diabetes. Here, we show that Stx2 acts to assist this precise tuning of insulin secretion in β-cells, including in diabetes.
Collapse
Affiliation(s)
- Fei Kang
- grid.17063.330000 0001 2157 2938Department of Medicine, Temerty Faculty of Medicine, University of Toronto, Toronto, ON M5S 1A8 Canada ,grid.231844.80000 0004 0474 0428Toronto General Hospital Research Institute, University Health Network, 200 Elizabeth Street, Toronto, ON M5G 2C4 Canada
| | - Li Xie
- grid.17063.330000 0001 2157 2938Department of Medicine, Temerty Faculty of Medicine, University of Toronto, Toronto, ON M5S 1A8 Canada
| | - Tairan Qin
- grid.17063.330000 0001 2157 2938Department of Medicine, Temerty Faculty of Medicine, University of Toronto, Toronto, ON M5S 1A8 Canada
| | - Yifan Miao
- grid.17063.330000 0001 2157 2938Department of Medicine, Temerty Faculty of Medicine, University of Toronto, Toronto, ON M5S 1A8 Canada
| | - Youhou Kang
- grid.17063.330000 0001 2157 2938Department of Medicine, Temerty Faculty of Medicine, University of Toronto, Toronto, ON M5S 1A8 Canada
| | - Toshimasa Takahashi
- grid.17063.330000 0001 2157 2938Department of Medicine, Temerty Faculty of Medicine, University of Toronto, Toronto, ON M5S 1A8 Canada
| | - Tao Liang
- grid.17063.330000 0001 2157 2938Department of Medicine, Temerty Faculty of Medicine, University of Toronto, Toronto, ON M5S 1A8 Canada ,grid.231844.80000 0004 0474 0428Toronto General Hospital Research Institute, University Health Network, 200 Elizabeth Street, Toronto, ON M5G 2C4 Canada
| | - Huanli Xie
- grid.17063.330000 0001 2157 2938Department of Medicine, Temerty Faculty of Medicine, University of Toronto, Toronto, ON M5S 1A8 Canada
| | - Herbert Y. Gaisano
- grid.17063.330000 0001 2157 2938Department of Medicine, Temerty Faculty of Medicine, University of Toronto, Toronto, ON M5S 1A8 Canada ,grid.231844.80000 0004 0474 0428Toronto General Hospital Research Institute, University Health Network, 200 Elizabeth Street, Toronto, ON M5G 2C4 Canada
| |
Collapse
|
4
|
Aissa HB, Gautier A. Engineering Glowing Chemogenetic Hybrids for Spying on Cells. European J Org Chem 2020. [DOI: 10.1002/ejoc.202000340] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Hela Ben Aissa
- École normale supérieure PSL University CNRS, Laboratoire des biomolécules, LBM Sorbonne Université 75005 Paris France
| | - Arnaud Gautier
- École normale supérieure PSL University CNRS, Laboratoire des biomolécules, LBM Sorbonne Université 75005 Paris France
- Institut Universitaire de France Paris France
| |
Collapse
|
5
|
Carpenter MA, Wang Y, Telmer CA, Schmidt BF, Yang Z, Bruchez MP. Protein Proximity Observed Using Fluorogen Activating Protein and Dye Activated by Proximal Anchoring (FAP-DAPA) System. ACS Chem Biol 2020; 15:2433-2443. [PMID: 32786268 DOI: 10.1021/acschembio.0c00419] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The development and function of tissues, blood, and the immune system is dependent upon proximity for cellular recognition and communication. However, the detection of cell-to-cell contacts is limited due to a lack of reversible, quantitative probes that can function at these dynamic sites of irregular geometry. Described here is a novel chemo-genetic tool developed for fluorescent detection of protein-protein proximity and cell apposition that utilizes the Fluorogen Activating Protein (FAP) in combination with a Dye Activated by Proximal Anchoring (DAPA). The FAP-DAPA system has two protein components, the HaloTag and FAP, expressed on separate protein targets or in separate cells. The proteins function to bind and activate a compound that has the hexyl chloride (HexCl) ligand connected to malachite green (MG), the FAP fluorogen, via a poly(ethylene glycol) spacer spanning up to 28 nm. The dehalogenase protein, HaloTag, covalently binds the HexCl ligand, locally concentrating the attached MG. If the FAP is within range of the anchored fluorogen, it will bind and activate MG specifically when the bath concentration is too low to saturate the FAP receptor. A new FAP variant was isolated with a 1000-fold reduced KD of ∼10-100 nM so that the fluorogen activation reports proximity without artificially enhancing it. The system was characterized using purified FRB and FKBP fusion proteins and showed a doubling of fluorescence upon rapamycin induced complex formation. In cocultured HEK293 cells (HaloTag and FAP-expressing) fluorescence increased at contact sites across a broad range of labeling conditions, more reliably providing contact-specific fluorescence activation with the lower-affinity FAP variant. When combined with suitable targeting and expression constructs, this labeling system may offer significant improvements in on-demand detection of intercellular contacts, potentially applicable in neurological and immunological synapse measurements and other transient, dynamic biological appositions that can be perturbed using other labeling methods that stabilize these interactions.
Collapse
Affiliation(s)
- M. Alexandra Carpenter
- Carnegie Mellon University, Department of Chemistry, 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - Yi Wang
- Carnegie Mellon University, Department of Biological Sciences, 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - Cheryl A. Telmer
- Carnegie Mellon University, Department of Biological Sciences, 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213, United States
- Carnegie Mellon University, Molecular Biosensor and Imaging Center, 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - Brigitte F. Schmidt
- Carnegie Mellon University, Molecular Biosensor and Imaging Center, 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - Zhipeng Yang
- Carnegie Mellon University, Department of Biological Sciences, 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - Marcel P. Bruchez
- Carnegie Mellon University, Department of Chemistry, 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213, United States
- Carnegie Mellon University, Department of Biological Sciences, 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213, United States
- Carnegie Mellon University, Molecular Biosensor and Imaging Center, 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213, United States
| |
Collapse
|
6
|
Perkins LA, Bruchez MP. Fluorogen activating protein toolset for protein trafficking measurements. Traffic 2020; 21:333-348. [PMID: 32080949 PMCID: PMC7462100 DOI: 10.1111/tra.12722] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Revised: 02/17/2020] [Accepted: 02/18/2020] [Indexed: 12/11/2022]
Abstract
Throughout the past decade the use of fluorogen activating proteins (FAPs) has expanded with several unique reporter dyes that support a variety of methods to specifically quantify protein trafficking events. The platform's capabilities have been demonstrated in several systems and shared for widespread use. This review will highlight the current FAP labeling techniques for protein traffic measurements and focus on the use of the different designed fluorogenic dyes for selective and specific labeling applications.
Collapse
Affiliation(s)
- Lydia A. Perkins
- School of MedicineUniversity of PittsburghPittsburghPennsylvaniaUSA
| | - Marcel P. Bruchez
- The Department of Biological SciencesCarnegie MellonPittsburghPennsylvaniaUSA
- Department of ChemistryCarnegie MellonPittsburghPennsylvaniaUSA
- Molecular and Biosensor Imaging CenterCarnegie MellonPittsburghPennsylvaniaUSA
| |
Collapse
|
7
|
Péresse T, Gautier A. Next-Generation Fluorogen-Based Reporters and Biosensors for Advanced Bioimaging. Int J Mol Sci 2019; 20:E6142. [PMID: 31817528 PMCID: PMC6940837 DOI: 10.3390/ijms20246142] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Revised: 12/04/2019] [Accepted: 12/04/2019] [Indexed: 12/17/2022] Open
Abstract
Our ability to observe biochemical events with high spatial and temporal resolution is essential for understanding the functioning of living systems. Intrinsically fluorescent proteins such as the green fluorescent protein (GFP) have revolutionized the way biologists study cells and organisms. The fluorescence toolbox has been recently extended with new fluorescent reporters composed of a genetically encoded tag that binds endogenously present or exogenously applied fluorogenic chromophores (so-called fluorogens) and activates their fluorescence. This review presents the toolbox of fluorogen-based reporters and biosensors available to biologists. Various applications are detailed to illustrate the possible uses and opportunities offered by this new generation of fluorescent probes and sensors for advanced bioimaging.
Collapse
Affiliation(s)
- Tiphaine Péresse
- Sorbonne Université, École Normale Supérieure, PSL University, CNRS, Laboratoire des Biomolécules, LBM, 75005 Paris, France;
| | - Arnaud Gautier
- Sorbonne Université, École Normale Supérieure, PSL University, CNRS, Laboratoire des Biomolécules, LBM, 75005 Paris, France;
- Institut Universitaire de France (IUF), 1 rue Descartes, 75005 Paris, France
| |
Collapse
|
8
|
Gallo E. Fluorogen-Activating Proteins: Next-Generation Fluorescence Probes for Biological Research. Bioconjug Chem 2019; 31:16-27. [DOI: 10.1021/acs.bioconjchem.9b00710] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- Eugenio Gallo
- Department of Molecular Genetics, University of Toronto, Charles Best Institute, 112 College Street, Toronto, Ontario M5G 1L6, Canada
| |
Collapse
|
9
|
Fluorescent labelling of membrane fatty acid transporter CD36 (SR-B2) in the extracellular loop. PLoS One 2019; 14:e0210704. [PMID: 30673728 PMCID: PMC6343965 DOI: 10.1371/journal.pone.0210704] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Accepted: 01/01/2019] [Indexed: 11/19/2022] Open
Abstract
Context Upon palmitate oversupply, membrane fatty acid-transporter CD36 (SR-B2) permanently translocates from endosomal storage to the sarcolemma, inducing lipotoxicity. CD36 translocation results from endosomal alkalinisation elicited by palmitate-induced disattachment of the cytoplasmic V1-subcomplex from the membrane-integrated V0-subcomplex of vacuolar-type H+-ATPase. Objective Develop a CD36 fluorescent labeling technique as initial step towards live cell imaging. Methods Three human CD36 (hCD36) mutants were constructed via insertion of a tetracysteine motif at different positions within the extracellular domain. Constructs were lentivirally transduced for subsequent CD36 labeling with fluorescein-arsenical hairpin-binder (FlAsH). Cell imaging was combined with V0/V1 immunostaining and Western blotting. Results Transduction of hCD36-wildtype and mutants yielded corresponding proteins in HL-1 cardiomyocytes. Tetracysteine mutant-2 (hCD36-TC2) showed similar fatty acid uptake to wildtype. FlAsH staining revealed a speckled pattern reminiscent of endosomes. We found decreased V1 co-localization with CD36 upon high-palmitate culturing. Conversely, V0 consistently co-localized with CD36. Conclusion hCD36-TC2 is a possible candidate for application of biarsenical dyes in live imaging studies pending further investigation. Our data is compatible with V0/V1 disassembly in high-palmitate-treated cells.
Collapse
|
10
|
Jaykumar AB, Caceres PS, Ortiz PA. Single-molecule labeling for studying trafficking of renal transporters. Am J Physiol Renal Physiol 2018; 315:F1243-F1249. [PMID: 30043625 DOI: 10.1152/ajprenal.00082.2017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The ability to detect and track single molecules presents the advantage of visualizing the complex behavior of transmembrane proteins with a time and space resolution that would otherwise be lost with traditional labeling and biochemical techniques. Development of new imaging probes has provided a robust method to study their trafficking and surface dynamics. This mini-review focuses on the current technology available for single-molecule labeling of transmembrane proteins, their advantages, and limitations. We also discuss the application of these techniques to the study of renal transporter trafficking in light of recent research.
Collapse
Affiliation(s)
- Ankita Bachhawat Jaykumar
- Hypertension and Vascular Research Division, Department of Internal Medicine, Henry Ford Hospital , Detroit, Michigan.,Department of Physiology, Wayne State University School of Medicine , Detroit, Michigan
| | - Paulo S Caceres
- Hypertension and Vascular Research Division, Department of Internal Medicine, Henry Ford Hospital , Detroit, Michigan
| | - Pablo A Ortiz
- Hypertension and Vascular Research Division, Department of Internal Medicine, Henry Ford Hospital , Detroit, Michigan.,Department of Physiology, Wayne State University School of Medicine , Detroit, Michigan
| |
Collapse
|
11
|
Emmerstorfer-Augustin A, Augustin CM, Shams S, Thorner J. Tracking yeast pheromone receptor Ste2 endocytosis using fluorogen-activating protein tagging. Mol Biol Cell 2018; 29:2720-2736. [PMID: 30207829 PMCID: PMC6249837 DOI: 10.1091/mbc.e18-07-0424] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
To observe internalization of the yeast pheromone receptor Ste2 by fluorescence microscopy in live cells in real time, we visualized only those molecules present at the cell surface at the time of agonist engagement (rather than the total cellular pool) by tagging this receptor at its N-terminus with an exocellular fluorogen-activating protein (FAP). A FAP is a single-chain antibody engineered to bind tightly a nonfluorescent, cell-impermeable dye (fluorogen), thereby generating a fluorescent complex. The utility of FAP tagging to study trafficking of integral membrane proteins in yeast, which possesses a cell wall, had not been examined previously. A diverse set of signal peptides and propeptide sequences were explored to maximize expression. Maintenance of the optimal FAP-Ste2 chimera intact required deletion of two, paralogous, glycosylphosphatidylinositol (GPI)-anchored extracellular aspartyl proteases (Yps1 and Mkc7). FAP-Ste2 exhibited a much brighter and distinct plasma membrane signal than Ste2-GFP or Ste2-mCherry yet behaved quite similarly. Using FAP-Ste2, new information was obtained about the mechanism of its internalization, including novel insights about the roles of the cargo-selective endocytic adaptors Ldb19/Art1, Rod1/Art4, and Rog3/Art7.
Collapse
Affiliation(s)
- Anita Emmerstorfer-Augustin
- Division of Biochemistry, Biophysics and Structural Biology, Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720-3202
| | - Christoph M Augustin
- Department of Mechanical Engineering, University of California, Berkeley, Berkeley, CA 94720-3202
| | - Shadi Shams
- Division of Biochemistry, Biophysics and Structural Biology, Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720-3202
| | - Jeremy Thorner
- Division of Biochemistry, Biophysics and Structural Biology, Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720-3202
| |
Collapse
|
12
|
Li C, Mourton A, Plamont MA, Rodrigues V, Aujard I, Volovitch M, Le Saux T, Perez F, Vriz S, Jullien L, Joliot A, Gautier A. Fluorogenic Probing of Membrane Protein Trafficking. Bioconjug Chem 2018; 29:1823-1828. [PMID: 29791141 DOI: 10.1021/acs.bioconjchem.8b00180] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Methods to differentially label cell-surface and intracellular membrane proteins are indispensable for understanding their function and the regulation of their trafficking. We present an efficient strategy for the rapid and selective fluorescent labeling of membrane proteins based on the chemical-genetic fluorescent marker FAST (fluorescence-activating and absorption-shifting tag). Cell-surface FAST-tagged proteins could be selectively and rapidly labeled using fluorogenic membrane-impermeant 4-hydroxybenzylidene rhodanine (HBR) analogs. This approach allows the study of protein trafficking at the plasma membrane with various fluorometric techniques, and opens exciting prospects for the high-throughput screening of small molecules able to restore disease-related trafficking defects.
Collapse
Affiliation(s)
- Chenge Li
- PASTEUR, Département de Chimie, École Normale Supérieure , PSL University, Sorbonne Université, CNRS , 75005 Paris , France
| | - Aurélien Mourton
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France , CNRS, INSERM, PSL Research University , 75231 Paris , France
- PSL Research University , 75006 Paris , France
| | - Marie-Aude Plamont
- PASTEUR, Département de Chimie, École Normale Supérieure , PSL University, Sorbonne Université, CNRS , 75005 Paris , France
| | - Vanessa Rodrigues
- PASTEUR, Département de Chimie, École Normale Supérieure , PSL University, Sorbonne Université, CNRS , 75005 Paris , France
| | - Isabelle Aujard
- PASTEUR, Département de Chimie, École Normale Supérieure , PSL University, Sorbonne Université, CNRS , 75005 Paris , France
| | - Michel Volovitch
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France , CNRS, INSERM, PSL Research University , 75231 Paris , France
- École Normale Supérieure, Department of Biology , PSL Research University , 75005 Paris , France
| | - Thomas Le Saux
- PASTEUR, Département de Chimie, École Normale Supérieure , PSL University, Sorbonne Université, CNRS , 75005 Paris , France
| | - Franck Perez
- Institut Curie, PSL Research University, CNRS UMR144 , 26 rue d'Ulm , 75248 Paris Cedex 05, France
| | - Sophie Vriz
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France , CNRS, INSERM, PSL Research University , 75231 Paris , France
- Université Paris Diderot, Sorbonne Paris Cité , Biology Department , 75205 Paris Cedex 13, France
| | - Ludovic Jullien
- PASTEUR, Département de Chimie, École Normale Supérieure , PSL University, Sorbonne Université, CNRS , 75005 Paris , France
| | - Alain Joliot
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France , CNRS, INSERM, PSL Research University , 75231 Paris , France
| | - Arnaud Gautier
- PASTEUR, Département de Chimie, École Normale Supérieure , PSL University, Sorbonne Université, CNRS , 75005 Paris , France
| |
Collapse
|
13
|
Xu S, Hu HY. Fluorogen-activating proteins: beyond classical fluorescent proteins. Acta Pharm Sin B 2018; 8:339-348. [PMID: 29881673 PMCID: PMC5989828 DOI: 10.1016/j.apsb.2018.02.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2017] [Revised: 02/11/2018] [Accepted: 02/18/2018] [Indexed: 01/09/2023] Open
Abstract
Fluorescence imaging is a powerful technique for the real-time noninvasive monitoring of protein dynamics. Recently, fluorogen activating proteins (FAPs)/fluorogen probes for protein imaging were developed. Unlike the traditional fluorescent proteins (FPs), FAPs do not fluoresce unless bound to their specific small-molecule fluorogens. When using FAPs/fluorogen probes, a washing step is not required for the removal of free probes from the cells, thus allowing rapid and specific detection of proteins in living cells with high signal-to-noise ratio. Furthermore, with different fluorogens, living cell multi-color proteins labeling system was developed. In this review, we describe about the discovery of FAPs, the design strategy of FAP fluorogens, the application of the FAP technology and the advances of FAP technology in protein labeling systems.
Collapse
Affiliation(s)
- Shengnan Xu
- State Key Laboratory of Bioactive Substances and Function of Natural Medicine, Institute of Materia Medica, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing 100050, China
| | - Hai-Yu Hu
- State Key Laboratory of Bioactive Substances and Function of Natural Medicine, Institute of Materia Medica, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing 100050, China
- Beijing Key Laboratory of Active Substances Discovery and Drugability Evaluation, Institute of Materia Medica, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing 100050, China
| |
Collapse
|
14
|
A cell surface display fluorescent biosensor for measuring MMP14 activity in real-time. Sci Rep 2018; 8:5916. [PMID: 29651043 PMCID: PMC5897415 DOI: 10.1038/s41598-018-24080-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Accepted: 03/23/2018] [Indexed: 01/16/2023] Open
Abstract
Despite numerous recent advances in imaging technologies, one continuing challenge for cell biologists and microscopists is the visualization and measurement of endogenous proteins as they function within living cells. Achieving this goal will provide a tool that investigators can use to associate cellular outcomes with the behavior and activity of many well-studied target proteins. Here, we describe the development of a plasmid-based fluorescent biosensor engineered to measure the location and activity of matrix metalloprotease-14 (MMP14). The biosensor design uses fluorogen-activating protein technology coupled with a MMP14-selective protease sequence to generate a binary, “switch-on” fluorescence reporter capable of measuring MMP14 location, activity, and temporal dynamics. The MMP14-fluorogen activating protein biosensor approach is applicable to both short and long-term imaging modalities and contains an adaptable module that can be used to study many membrane-bound proteases. This MMP14 biosensor promises to serve as a tool for the advancement of a broad range of investigations targeting MMP14 activity during cell migration in health and disease.
Collapse
|
15
|
Perkins LA, Fisher GW, Naganbabu M, Schmidt BF, Mun F, Bruchez MP. High-Content Surface and Total Expression siRNA Kinase Library Screen with VX-809 Treatment Reveals Kinase Targets that Enhance F508del-CFTR Rescue. Mol Pharm 2018; 15:759-767. [PMID: 29384380 PMCID: PMC5844356 DOI: 10.1021/acs.molpharmaceut.7b00928] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
![]()
The most promising
F508del-CFTR corrector, VX-809, has been unsuccessful
as an effective, stand-alone treatment for CF patients, but the rescue
effect in combination with other drugs may confer an acceptable level
of therapeutic benefit. Targeting cellular factors that modify trafficking
may act to enhance the cell surface density of F508-CFTR with VX-809
correction. Our goal is to identify druggable kinases that enhance
F508del-CFTR rescue and stabilization at the cell surface beyond that
achievable with the VX-809 corrector alone. To achieve this goal,
we implemented a new high-throughput screening paradigm that quickly
and quantitatively measures surface density and total protein in the
same cells. This allowed for rapid screening for increased surface
targeting and proteostatic regulation. The assay utilizes fluorogen-activating-protein
(FAP) technology with cell excluded and cell permeant fluorogenic
dyes in a quick, wash-free fluorescent plate reader format on live
cells to first measure F508del-CFTR expressed on the surface and then
the total amount of F508del-CFTR protein present. To screen for kinase
targets, we used Dharmacon’s ON-TARGETplus SMARTpool siRNA Kinase library (715 target kinases) with and without
10 μM VX-809 treatment in triplicate at 37 °C. We identified
several targets that had a significant interaction with VX-809 treatment
in enhancing surface density with siRNA knockdown. Select small-molecule
inhibitors of the kinase targets demonstrated augmented surface expression
with VX-809 treatment.
Collapse
Affiliation(s)
| | | | - Matharishwan Naganbabu
- Department of Chemistry , University of California , Berkeley , California 94720 , United States
| | | | | | | |
Collapse
|
16
|
Giuliano KA, Wachi S, Drew L, Dukovski D, Green O, Bastos C, Cullen MD, Hauck S, Tait BD, Munoz B, Lee PS, Miller JP. Use of a High-Throughput Phenotypic Screening Strategy to Identify Amplifiers, a Novel Pharmacological Class of Small Molecules That Exhibit Functional Synergy with Potentiators and Correctors. SLAS DISCOVERY : ADVANCING LIFE SCIENCES R & D 2018; 23:111-121. [PMID: 28898585 PMCID: PMC5784457 DOI: 10.1177/2472555217729790] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Accepted: 08/09/2017] [Indexed: 11/21/2022]
Abstract
Cystic fibrosis (CF) is a lethal genetic disorder caused by mutation of the cystic fibrosis transmembrane conductance regulator (CFTR) gene. Despite recent groundbreaking approval of genotype-specific small-molecule drugs, a significant portion of CF patients still lack effective therapeutic options that address the underlying cause of the disease. Through a phenotypic high-throughput screen of approximately 54,000 small molecules, we identified a novel class of CFTR modulators called amplifiers. The identified compound, the characteristics of which are represented here by PTI-CH, selectively increases the expression of immature CFTR protein across different CFTR mutations, including F508del-CFTR, by targeting the inefficiencies of early CFTR biosynthesis. PTI-CH also augments the activity of other CFTR modulators and was found to possess novel characteristics that distinguish it from CFTR potentiator and corrector moieties. The PTI-CH-mediated increase in F508del-CFTR did not elicit cytosolic or endoplasmic reticulum-associated cellular stress responses. Based on these data, amplifiers represent a promising new class of CFTR modulators for the treatment of CF that can be used synergistically with other CFTR modulators.
Collapse
Affiliation(s)
| | | | | | | | - Olivia Green
- Proteostasis Therapeutics, Inc., Cambridge, MA, USA
| | | | | | - Sheila Hauck
- Proteostasis Therapeutics, Inc., Cambridge, MA, USA
| | | | - Benito Munoz
- Proteostasis Therapeutics, Inc., Cambridge, MA, USA
| | - Po-Shun Lee
- Proteostasis Therapeutics, Inc., Cambridge, MA, USA
| | | |
Collapse
|
17
|
Conner JW. Fluorogens: Generating Receptor-Specific Turn-On Fluorescence. Aust J Chem 2018. [DOI: 10.1071/ch17492] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
|
18
|
Li C, Tebo AG, Gautier A. Fluorogenic Labeling Strategies for Biological Imaging. Int J Mol Sci 2017; 18:ijms18071473. [PMID: 28698494 PMCID: PMC5535964 DOI: 10.3390/ijms18071473] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Revised: 07/03/2017] [Accepted: 07/06/2017] [Indexed: 12/27/2022] Open
Abstract
The spatiotemporal fluorescence imaging of biological processes requires effective tools to label intracellular biomolecules in living systems. This review presents a brief overview of recent labeling strategies that permits one to make protein and RNA strongly fluorescent using synthetic fluorogenic probes. Genetically encoded tags selectively binding the exogenously applied molecules ensure high labeling selectivity, while high imaging contrast is achieved using fluorogenic chromophores that are fluorescent only when bound to their cognate tag, and are otherwise dark. Beyond avoiding the need for removal of unbound synthetic dyes, these approaches allow the development of sophisticated imaging assays, and open exciting prospects for advanced imaging, particularly for multiplexed imaging and super-resolution microscopy.
Collapse
Affiliation(s)
- Chenge Li
- École Normale Supérieure, PSL Research University, UPMC Univ Paris 06, CNRS, Département de Chimie, PASTEUR, 24 rue Lhomond, 75005 Paris, France.
- Sorbonne Universités, UPMC Univ Paris 06, ENS, CNRS, PASTEUR, 75005 Paris, France.
| | - Alison G Tebo
- École Normale Supérieure, PSL Research University, UPMC Univ Paris 06, CNRS, Département de Chimie, PASTEUR, 24 rue Lhomond, 75005 Paris, France.
- Sorbonne Universités, UPMC Univ Paris 06, ENS, CNRS, PASTEUR, 75005 Paris, France.
| | - Arnaud Gautier
- École Normale Supérieure, PSL Research University, UPMC Univ Paris 06, CNRS, Département de Chimie, PASTEUR, 24 rue Lhomond, 75005 Paris, France.
- Sorbonne Universités, UPMC Univ Paris 06, ENS, CNRS, PASTEUR, 75005 Paris, France.
| |
Collapse
|
19
|
Gallo E, Jarvik JW. Breaking the color barrier - a multi-selective antibody reporter offers innovative strategies of fluorescence detection. J Cell Sci 2017; 130:2644-2653. [PMID: 28615413 DOI: 10.1242/jcs.202952] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2017] [Accepted: 06/08/2017] [Indexed: 01/14/2023] Open
Abstract
A novel bi-partite fluorescence platform exploits the high affinity and selectivity of antibody scaffolds to capture and activate small-molecule fluorogens. In this report, we investigated the property of multi-selectivity activation by a single antibody against diverse cyanine family fluorogens. Our fluorescence screen identified three cell-impermeant fluorogens, each with unique emission spectra (blue, green and red) and nanomolar affinities. Most importantly, as a protein fusion tag to G-protein-coupled receptors, the antibody biosensor retained full activity - displaying bright fluorogen signals with minimal background on live cells. Because fluorogen-activating antibodies interact with their target ligands via non-covalent interactions, we were able to perform advanced multi-color detection strategies on live cells, previously difficult or impossible with conventional reporters. We found that by fine-tuning the concentrations of the different color fluorogen molecules in solution, a user may interchange the fluorescence signal (onset versus offset), execute real-time signal exchange via fluorogen competition, measure multi-channel fluorescence via co-labeling, and assess real-time cell surface receptor traffic via pulse-chase experiments. Thus, here we inform of an innovative reporter technology based on tri-color signal that allows user-defined fluorescence tuning in live-cell applications.
Collapse
Affiliation(s)
- Eugenio Gallo
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - Jonathan W Jarvik
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213, USA.,Molecular Biosensor and Imaging Center, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| |
Collapse
|
20
|
Ackerman DS, Vasilev KV, Schmidt BF, Cohen LB, Jarvik JW. Tethered Fluorogen Assay to Visualize Membrane Apposition in Living Cells. Bioconjug Chem 2017; 28:1356-1362. [DOI: 10.1021/acs.bioconjchem.7b00047] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Daniel S. Ackerman
- Department of Biological Sciences, ‡Department of Chemistry, and §Molecular Biosensor
and Imaging Center, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - Kalin V. Vasilev
- Department of Biological Sciences, ‡Department of Chemistry, and §Molecular Biosensor
and Imaging Center, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - Brigitte F. Schmidt
- Department of Biological Sciences, ‡Department of Chemistry, and §Molecular Biosensor
and Imaging Center, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - Lianne B. Cohen
- Department of Biological Sciences, ‡Department of Chemistry, and §Molecular Biosensor
and Imaging Center, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - Jonathan W. Jarvik
- Department of Biological Sciences, ‡Department of Chemistry, and §Molecular Biosensor
and Imaging Center, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
| |
Collapse
|
21
|
Effect of human cytomegalovirus (HCMV) US27 on CXCR4 receptor internalization measured by fluorogen-activating protein (FAP) biosensors. PLoS One 2017; 12:e0172042. [PMID: 28207860 PMCID: PMC5313195 DOI: 10.1371/journal.pone.0172042] [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: 12/01/2016] [Accepted: 01/30/2017] [Indexed: 01/08/2023] Open
Abstract
Human cytomegalovirus (HCMV) is a widespread pathogen and a member of the Herpesviridae family. HCMV has a large genome that encodes many genes that are non-essential for virus replication but instead play roles in manipulation of the host immune environment. One of these is the US27 gene, which encodes a protein with homology to the chemokine receptor family of G protein-coupled receptors (GPCRs). The US27 protein has no known chemokine ligands but can modulate the signaling activity of host receptor CXCR4. We investigated the mechanism for enhanced CXCR4 signaling in the presence of US27 using a novel biosensor system comprised of fluorogen activating proteins (FAPs). FAP-tagged CXCR4 and US27 were used to explore receptor internalization and recovery dynamics, and the results demonstrate that significantly more CXCR4 internalization was observed in the presence of US27 compared to CXCR4 alone upon stimulation with CXCL12. While ligand-induced endocytosis rates were higher, steady state internalization of CXCR4 was not affected by US27. Additionally, US27 underwent rapid endocytosis at a rate that was independent of either CXCR4 expression or CXCL12 stimulation. These results demonstrate that one mechanism by which US27 can enhance CXCR4 signaling is to alter receptor internalization dynamics, which could ultimately have the effect of promoting virus dissemination by increasing trafficking of HCMV-infected cells to tissues where CXCL12 is highly expressed.
Collapse
|
22
|
Generation of Fluorogen-Activating Designed Ankyrin Repeat Proteins (FADAs) as Versatile Sensor Tools. J Mol Biol 2016; 428:1272-1289. [PMID: 26812208 DOI: 10.1016/j.jmb.2016.01.017] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Revised: 01/12/2016] [Accepted: 01/15/2016] [Indexed: 11/21/2022]
Abstract
Fluorescent probes constitute a valuable toolbox to address a variety of biological questions and they have become irreplaceable for imaging methods. Commonly, such probes consist of fluorescent proteins or small organic fluorophores coupled to biological molecules of interest. Recently, a novel class of fluorescence-based probes, fluorogen-activating proteins (FAPs), has been reported. These binding proteins are based on antibody single-chain variable fragments and activate fluorogenic dyes, which only become fluorescent upon activation and do not fluoresce when free in solution. Here we present a novel class of fluorogen activators, termed FADAs, based on the very robust designed ankyrin repeat protein scaffold, which also readily folds in the reducing environment of the cytoplasm. The FADA generated in this study was obtained by combined selections with ribosome display and yeast surface display. It enhances the fluorescence of malachite green (MG) dyes by a factor of more than 11,000 and thus activates MG to a similar extent as FAPs based on single-chain variable fragments. As shown by structure determination and in vitro measurements, this FADA was evolved to form a homodimer for the activation of MG dyes. Exploiting the favorable properties of the designed ankyrin repeat protein scaffold, we created a FADA biosensor suitable for imaging of proteins on the cell surface, as well as in the cytosol. Moreover, based on the requirement of dimerization for strong fluorogen activation, a prototype FADA biosensor for in situ detection of a target protein and protein-protein interactions was developed. Therefore, FADAs are versatile fluorescent probes that are easily produced and suitable for diverse applications and thus extend the FAP technology.
Collapse
|
23
|
Yan Q, Schmidt BF, Perkins LA, Naganbabu M, Saurabh S, Andreko SK, Bruchez MP. Near-instant surface-selective fluorogenic protein quantification using sulfonated triarylmethane dyes and fluorogen activating proteins. Org Biomol Chem 2015; 13:2078-86. [PMID: 25520058 DOI: 10.1039/c4ob02309a] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Agonist-promoted G-protein coupled receptor (GPCR) endocytosis and recycling plays an important role in many signaling events in the cell. However, the approaches that allow fast and quantitative analysis of such processes still remain limited. Here we report an improved labeling approach based on the genetic fusion of a fluorogen activating protein (FAP) to a GPCR and binding of a sulfonated analog of the malachite green (MG) fluorogen to rapidly and selectively label cell surface receptors. Fluorescence microscopy and flow cytometry demonstrate that this dye does not cross the plasma membrane, binds with high affinity to a dL5** FAP-GPCR fusion construct, activating tagged surface receptors within seconds of addition. The ability to rapidly and selectively label cell surface receptors with a fluorogenic genetically encoded tag allows quantitative imaging and analysis of highly dynamic processes like receptor endocytosis and recycling.
Collapse
Affiliation(s)
- Qi Yan
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA, USA.
| | | | | | | | | | | | | |
Collapse
|
24
|
Pham HH, Szent-Gyorgyi C, Brotherton WL, Schmidt BF, Zanotti KJ, Waggoner AS, Armitage BA. Bichromophoric dyes for wavelength shifting of dye-protein fluoromodules. Org Biomol Chem 2015; 13:3699-710. [PMID: 25679477 DOI: 10.1039/c4ob02522a] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Dye-protein fluoromodules consist of fluorogenic dyes and single chain antibody fragments that form brightly fluorescent noncovalent complexes. This report describes two new bichromophoric dyes that extend the range of wavelengths of excitation or emission of existing fluoromodules. In one case, a fluorogenic thiazole orange (TO) was attached to an energy acceptor dye, Cy5. Upon binding to a protein that recognizes TO, red emission due to efficient energy transfer from TO to Cy5 replaces the green emission observed for monochromophoric TO bound to the same protein. Separately, TO was attached to a coumarin that serves as an energy donor. The same green emission is observed for coumarin-TO and TO bound to a protein, but efficient energy transfer allows violet excitation of coumarin-TO, versus longer wavelength, blue excitation of monochromophoric TO. Both bichromophores exhibit low nanomolar KD values for their respective proteins, >95% energy transfer efficiency and high fluorescence quantum yields.
Collapse
Affiliation(s)
- Ha H Pham
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, PA 15213, USA
| | | | | | | | | | | | | |
Collapse
|
25
|
Wu Y, Stauffer SR, Stanfield RL, Tapia PH, Ursu O, Fisher GW, Szent-Gyorgyi C, Evangelisti A, Waller A, Strouse JJ, Carter MB, Bologa C, Gouveia K, Poslusney M, Waggoner AS, Lindsley CW, Jarvik JW, Sklar LA. Discovery of Small-Molecule Nonfluorescent Inhibitors of Fluorogen-Fluorogen Activating Protein Binding Pair. ACTA ACUST UNITED AC 2015; 21:74-87. [PMID: 26442911 DOI: 10.1177/1087057115609145] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Accepted: 09/09/2015] [Indexed: 11/17/2022]
Abstract
A new class of biosensors, fluorogen activating proteins (FAPs), has been successfully used to track receptor trafficking in live cells. Unlike the traditional fluorescent proteins (FPs), FAPs do not fluoresce unless bound to their specific small-molecule fluorogens, and thus FAP-based assays are highly sensitive. Application of the FAP-based assay for protein trafficking in high-throughput flow cytometry resulted in the discovery of a new class of compounds that interferes with the binding between fluorogens and FAP, thus blocking the fluorescence signal. These compounds are high-affinity, nonfluorescent analogs of fluorogens with little or no toxicity to the tested cells and no apparent interference with the normal function of FAP-tagged receptors. The most potent compound among these, N,4-dimethyl-N-(2-oxo-2-(4-(pyridin-2-yl)piperazin-1-yl)ethyl)benzenesulfonamide (ML342), has been investigated in detail. X-ray crystallographic analysis revealed that ML342 competes with the fluorogen, sulfonated thiazole orange coupled to diethylene glycol diamine (TO1-2p), for the same binding site on a FAP, AM2.2. Kinetic analysis shows that the FAP-fluorogen interaction is more complex than a homogeneous one-site binding process, with multiple conformational states of the fluorogen and/or the FAP, and possible dimerization of the FAP moiety involved in the process.
Collapse
Affiliation(s)
- Yang Wu
- Department of Pathology, University of New Mexico, Albuquerque, NM, USA Center for Molecular Discovery, University of New Mexico, Albuquerque, NM, USA
| | - Shaun R Stauffer
- Vanderbilt Specialized Chemistry Center, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Robyn L Stanfield
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA, USA
| | - Phillip H Tapia
- Center for Molecular Discovery, University of New Mexico, Albuquerque, NM, USA
| | - Oleg Ursu
- Center for Molecular Discovery, University of New Mexico, Albuquerque, NM, USA
| | - Gregory W Fisher
- Molecular Biosensor and Imaging Center, Carnegie Mellon University, Pittsburgh, PA, USA
| | | | - Annette Evangelisti
- Center for Molecular Discovery, University of New Mexico, Albuquerque, NM, USA
| | - Anna Waller
- Center for Molecular Discovery, University of New Mexico, Albuquerque, NM, USA
| | - J Jacob Strouse
- Center for Molecular Discovery, University of New Mexico, Albuquerque, NM, USA
| | - Mark B Carter
- Center for Molecular Discovery, University of New Mexico, Albuquerque, NM, USA
| | - Cristian Bologa
- Center for Molecular Discovery, University of New Mexico, Albuquerque, NM, USA
| | - Kristine Gouveia
- Center for Molecular Discovery, University of New Mexico, Albuquerque, NM, USA
| | - Mike Poslusney
- Vanderbilt Specialized Chemistry Center, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Alan S Waggoner
- Molecular Biosensor and Imaging Center, Carnegie Mellon University, Pittsburgh, PA, USA Department of Biological Science, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Craig W Lindsley
- Vanderbilt Specialized Chemistry Center, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Jonathan W Jarvik
- Molecular Biosensor and Imaging Center, Carnegie Mellon University, Pittsburgh, PA, USA Department of Biological Science, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Larry A Sklar
- Department of Pathology, University of New Mexico, Albuquerque, NM, USA Center for Molecular Discovery, University of New Mexico, Albuquerque, NM, USA
| |
Collapse
|
26
|
Pratt CP, He J, Wang Y, Barth AL, Bruchez MP. Fluorogenic Green-Inside Red-Outside (GIRO) Labeling Approach Reveals Adenylyl Cyclase-Dependent Control of BKα Surface Expression. Bioconjug Chem 2015; 26:1963-71. [PMID: 26301573 PMCID: PMC4576318 DOI: 10.1021/acs.bioconjchem.5b00409] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
![]()
The
regulation of surface levels of protein is critical for proper
cell function and influences properties including cell adhesion, ion
channel contributions to current flux, and the sensitivity of surface
receptors to ligands. Here we demonstrate a two-color labeling system
in live cells using a single fluorogen activating peptide (FAP) based
fusion tag, which enables the rapid and simultaneous quantification
of surface and internal proteins. In the nervous system, BK channels
can regulate neural excitability and neurotransmitter release, and
the surface trafficking of BK channels can be modulated by signaling
cascades and assembly with accessory proteins. Using this labeling
approach, we examine the dynamics of BK channel surface expression
in HEK293 cells. Surface pools of the pore-forming BKα subunit
were stable, exhibiting a plasma membrane half-life of >10 h. Long-term
activation of adenylyl cyclase by forskolin reduced BKα surface
levels by 30%, an effect that could not be attributed to increased
bulk endocytosis of plasma membrane proteins. This labeling approach
is compatible with microscopic imaging and flow cytometry, providing
a solid platform for examining protein trafficking in living cells.
Collapse
Affiliation(s)
- Christopher P Pratt
- Department of Biological Sciences, ‡Department of Chemistry, §Molecular Biosensor and Imaging Center, and #Center for the Neural Basis of Cognition, Carnegie Mellon University , 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - Jianjun He
- Department of Biological Sciences, ‡Department of Chemistry, §Molecular Biosensor and Imaging Center, and #Center for the Neural Basis of Cognition, Carnegie Mellon University , 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - Yi Wang
- Department of Biological Sciences, ‡Department of Chemistry, §Molecular Biosensor and Imaging Center, and #Center for the Neural Basis of Cognition, Carnegie Mellon University , 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - Alison L Barth
- Department of Biological Sciences, ‡Department of Chemistry, §Molecular Biosensor and Imaging Center, and #Center for the Neural Basis of Cognition, Carnegie Mellon University , 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - Marcel P Bruchez
- Department of Biological Sciences, ‡Department of Chemistry, §Molecular Biosensor and Imaging Center, and #Center for the Neural Basis of Cognition, Carnegie Mellon University , 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
| |
Collapse
|
27
|
Edwards BS, Sklar LA. Flow Cytometry: Impact on Early Drug Discovery. JOURNAL OF BIOMOLECULAR SCREENING 2015; 20:689-707. [PMID: 25805180 PMCID: PMC4606936 DOI: 10.1177/1087057115578273] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Accepted: 02/27/2015] [Indexed: 12/15/2022]
Abstract
Modern flow cytometers can make optical measurements of 10 or more parameters per cell at tens of thousands of cells per second and more than five orders of magnitude dynamic range. Although flow cytometry is used in most drug discovery stages, "sip-and-spit" sampling technology has restricted it to low-sample-throughput applications. The advent of HyperCyt sampling technology has recently made possible primary screening applications in which tens of thousands of compounds are analyzed per day. Target-multiplexing methodologies in combination with extended multiparameter analyses enable profiling of lead candidates early in the discovery process, when the greatest numbers of candidates are available for evaluation. The ability to sample small volumes with negligible waste reduces reagent costs, compound usage, and consumption of cells. Improved compound library formatting strategies can further extend primary screening opportunities when samples are scarce. Dozens of targets have been screened in 384- and 1536-well assay formats, predominantly in academic screening lab settings. In concert with commercial platform evolution and trending drug discovery strategies, HyperCyt-based systems are now finding their way into mainstream screening labs. Recent advances in flow-based imaging, mass spectrometry, and parallel sample processing promise dramatically expanded single-cell profiling capabilities to bolster systems-level approaches to drug discovery.
Collapse
Affiliation(s)
- Bruce S Edwards
- Center for Molecular Discovery, Innovation Discovery and Training Center, Health Sciences Center, University of New Mexico, Albuquerque, NM, USA
| | - Larry A Sklar
- Center for Molecular Discovery, Innovation Discovery and Training Center, Health Sciences Center, University of New Mexico, Albuquerque, NM, USA
| |
Collapse
|
28
|
Gallo E, Snyder AC, Jarvik JW. Engineering tandem single-chain Fv as cell surface reporters with enhanced properties of fluorescence detection. Protein Eng Des Sel 2015; 28:327-37. [PMID: 25843939 DOI: 10.1093/protein/gzv016] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Accepted: 02/20/2015] [Indexed: 12/13/2022] Open
Abstract
A recently described fluorescence biosensor platform utilizes single-chain Fv (scFvs) that selectively bind and activate fluorogen molecules. In this report we investigated the display of tandem scFv biosensors at the surface of mammalian cells with the aim of advancing current fluorescence detection strategies. We initially screened different peptide linkers to separate each scFv unit, and discovered that tandem proteins joined by either flexible or α-helical linkers properly fold and display at the surface of mammalian cells. Accordingly, we performed a combinatorial scFv-dimer study and identified that fluorescence activation correlated with the cellular location (membrane distal versus proximal) and selections of the different scFvs. Furthermore, in vitro measurements showed that the stability of each scFv monomer unit influenced the folding and cell surface activities of tandem scFvs. Additionally, we investigated the absence or poor signals from some scFv-dimer combinations and discovered that intramolecular and intermolecular scFv chain mispairings led to protein misfolding and/or secretory-pathway-mediated degradation. Furthermore, when tandem scFvs were utilized as fluorescence reporter tags with surface receptors, the biosensor unit and target protein showed independent activities. Thus, the live cell application of tandem scFvs permitted advanced detection of target proteins via fluorescence signal amplification, Förster resonance energy transfer resulting in the increase of Stokes shift and multi-color vesicular traffic of surface receptors.
Collapse
Affiliation(s)
- Eugenio Gallo
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - Avin C Snyder
- Molecular Biosensor and Imaging Center, Pittsburgh, PA 15213, USA
| | - Jonathan W Jarvik
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213, USA Molecular Biosensor and Imaging Center, Pittsburgh, PA 15213, USA
| |
Collapse
|
29
|
Yan Q, Bruchez MP. Advances in chemical labeling of proteins in living cells. Cell Tissue Res 2015; 360:179-94. [PMID: 25743694 PMCID: PMC4380784 DOI: 10.1007/s00441-015-2145-4] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2015] [Accepted: 02/02/2015] [Indexed: 01/07/2023]
Abstract
The pursuit of quantitative biological information via imaging requires robust labeling approaches that can be used in multiple applications and with a variety of detectable colors and properties. In addition to conventional fluorescent proteins, chemists and biologists have come together to provide a range of approaches that combine dye chemistry with the convenience of genetic targeting. This hybrid-tagging approach amalgamates the rational design of properties available through synthetic dye chemistry with the robust biological targeting available with genetic encoding. In this review, we discuss the current range of approaches that have been exploited for dye targeting or for targeting and activation and some of the recent applications that are uniquely permitted by these hybrid-tagging approaches.
Collapse
Affiliation(s)
- Qi Yan
- Sharp Edge Laboratories, Inc. Pittsburgh, PA
| | - Marcel P. Bruchez
- Sharp Edge Laboratories, Inc. Pittsburgh, PA
- Molecular Biosensor and Imaging Center, Carnegie Mellon University, Pittsburgh, PA
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, PA
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA
| |
Collapse
|
30
|
Protein traffic disorders: an effective high-throughput fluorescence microscopy pipeline for drug discovery. Sci Rep 2015; 5:9038. [PMID: 25762484 PMCID: PMC4356983 DOI: 10.1038/srep09038] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2015] [Accepted: 02/13/2015] [Indexed: 12/12/2022] Open
Abstract
Plasma membrane proteins are essential molecules in the cell which mediate interactions with the exterior milieu, thus representing key drug targets for present pharma. Not surprisingly, protein traffic disorders include a large range of diseases sharing the common mechanism of failure in the respective protein to reach the plasma membrane. However, specific therapies for these diseases are remarkably lacking. Herein, we report a robust platform for drug discovery applied to a paradigmatic genetic disorder affecting intracellular trafficking – Cystic Fibrosis. This platform includes (i) two original respiratory epithelial cellular models incorporating an inducible double-tagged traffic reporter; (ii) a plasma membrane protein traffic assay for high-throughput microscopy screening; and (iii) open-source image analysis software to quantify plasma membrane protein traffic. By allowing direct scoring of compounds rescuing the basic traffic defect, this platform enables an effective drug development pipeline, which can be promptly adapted to any traffic disorder-associated protein and leverage therapy development efforts.
Collapse
|
31
|
Yapici I, Lee KSS, Berbasova T, Nosrati M, Jia X, Vasileiou C, Wang W, Santos EM, Geiger JH, Borhan B. "Turn-on" protein fluorescence: in situ formation of cyanine dyes. J Am Chem Soc 2015; 137:1073-80. [PMID: 25534273 PMCID: PMC4311949 DOI: 10.1021/ja506376j] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Protein reengineering of cellular retinoic acid binding protein II (CRABPII) has yielded a genetically addressable system, capable of binding a profluorophoric chromophore that results in fluorescent protein/chromophore complexes. These complexes exhibit far-red emission, with high quantum efficiencies and brightness and also exhibit excellent pH stability spanning the range of 2-11. In the course of this study, it became evident that single mutations of L121E and R59W were most effective in improving the fluorescent characteristics of CRABPII mutants as well as the kinetics of complex formation. The readily crystallizable nature of these proteins was invaluable to provide clues for the observed spectroscopic behavior that results from single mutation of key residues.
Collapse
Affiliation(s)
- Ipek Yapici
- Department of Chemistry, Michigan State University , East Lansing, Michigan 48824, United States
| | | | | | | | | | | | | | | | | | | |
Collapse
|
32
|
Saurabh S, Beck LE, Maji S, Baty CJ, Wang Y, Yan Q, Watkins SC, Bruchez MP. Multiplexed modular genetic targeting of quantum dots. ACS NANO 2014; 8:11138-46. [PMID: 25380615 PMCID: PMC4246007 DOI: 10.1021/nn5044367] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2014] [Accepted: 11/07/2014] [Indexed: 05/19/2023]
Abstract
While DNA-directed nanotechnology is now a well-established platform for bioinspired nanoscale assembly in vitro, the direct targeting of various nanomaterials in living biological systems remains a significant challenge. Hybrid biological systems with integrated and targeted nanomaterials may have interesting and exploitable properties, so methods for targeting various nanomaterials to precise biological locations are required. Fluorescence imaging has benefited from the use of nanoparticles with superior optical properties compared to fluorescent organic dyes or fluorescent proteins. While single-particle tracking (SPT) in living cells with genetically encoded proteins is limited to very short trajectories, the high photon output of genetically targeted and multiplexed quantum dots (QDs) would enable long-trajectory analysis of multiple proteins. However, challenges with genetic targeting of QDs limit their application in these experiments. In this report, we establish a modular method for targeting QD nanoparticles selectively to multiple genetically encoded tags by precomplexing QD-streptavidin conjugates with cognate biotinylated hapten molecules. This approach enables labeling and SPT of multiple genetically encoded proteins on living cells at high speed and can label expressed proteins in the cytosol upon microinjection into living cells. While we demonstrate labeling with three distinct QD conjugates, the approach can be extended to other specific hapten-affinity molecule interactions and alternative nanoparticles, enabling precise directed targeting of nanoparticles in living biological systems.
Collapse
Affiliation(s)
- Saumya Saurabh
- Department of Chemistry, Molecular Biosensor and Imaging Center, Department of Physics, Lane Center for Computational Biology, and Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania, United States
| | - Lauren E. Beck
- Department of Chemistry, Molecular Biosensor and Imaging Center, Department of Physics, Lane Center for Computational Biology, and Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania, United States
| | - Suvrajit Maji
- Department of Chemistry, Molecular Biosensor and Imaging Center, Department of Physics, Lane Center for Computational Biology, and Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania, United States
| | - Catherine J. Baty
- Department of Cell Biology, Center for Biological Imaging, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
| | - Yi Wang
- Department of Chemistry, Molecular Biosensor and Imaging Center, Department of Physics, Lane Center for Computational Biology, and Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania, United States
| | - Qi Yan
- Department of Chemistry, Molecular Biosensor and Imaging Center, Department of Physics, Lane Center for Computational Biology, and Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania, United States
| | - Simon C. Watkins
- Department of Cell Biology, Center for Biological Imaging, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
| | - Marcel P. Bruchez
- Department of Chemistry, Molecular Biosensor and Imaging Center, Department of Physics, Lane Center for Computational Biology, and Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania, United States
- Address correspondence to
| |
Collapse
|
33
|
Saunders MJ, Block E, Sorkin A, Waggoner AS, Bruchez MP. A bifunctional converter: fluorescein quenching scFv/fluorogen activating protein for photostability and improved signal to noise in fluorescence experiments. Bioconjug Chem 2014; 25:1556-64. [PMID: 25072845 PMCID: PMC4140548 DOI: 10.1021/bc500273n] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
![]()
Monoclonal antibodies are one of
the most useful and ubiquitous
affinity reagents used in the biological sciences. Immunostaining
of fixed and live cells for microscopy or cytometry measurements frequently
employs fluorescently labeled antibodies, in particular fluorescein-labeled
antibodies. This dye emits light at a wavelength overlapping with
cellular autofluorescence, making it difficult to measure antibody
binding to proteins of relatively low copy number or in cells of high
green autofluorescence. A number of high affinity fluorescein binding
antibodies and antibody domains have been developed that quench the
dye’s fluorescence. Using a fluorescein-binding recombinant
antibody domain genetically fused to a fluorogen activating protein
(FAP), we demonstrate a molecular converter capable of binding and
quenching fluorescein, while binding and activating a fluorogenic
triarylmethane dye. This reagent converts fluorescein conjugates to
far-red fluorescent probes, where cellular autofluorescence is low,
improving signal-to-background of cell-based antibody binding measurements
by ∼7-fold. Microscopy experiments show colocalization of both
fluorescein and MG fluorescence. This dual affinity fluorescein-quenching-FAP
can also be used to convert fluorescein to the red fluorescing MG
fluorogen on biological molecules other than antibodies.
Collapse
Affiliation(s)
- Matthew J Saunders
- Molecular Biosensor and Imaging Center, §Department of Biological Sciences, ∥Department of Chemistry, Carnegie-Mellon University , Pittsburgh, Pennsylvania 15213, United States
| | | | | | | | | |
Collapse
|
34
|
Salipalli S, Singh PK, Borlak J. Recent advances in live cell imaging of hepatoma cells. BMC Cell Biol 2014; 15:26. [PMID: 25005127 PMCID: PMC4108253 DOI: 10.1186/1471-2121-15-26] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2013] [Accepted: 06/25/2014] [Indexed: 11/10/2022] Open
Abstract
Live cell imaging enables the study of dynamic processes of living cells in real time by use of suitable reporter proteins and the staining of specific cellular structures and/or organelles. With the availability of advanced optical devices and improved cell culture protocols it has become a rapidly growing research methodology. The success of this technique relies mainly on the selection of suitable reporter proteins, construction of recombinant plasmids possessing cell type specific promoters as well as reliable methods of gene transfer. This review aims to provide an overview of the recent developments in the field of marker proteins (bioluminescence and fluorescent) and methodologies (fluorescent resonance energy transfer, fluorescent recovery after photobleaching and proximity ligation assay) employed as to achieve an improved imaging of biological processes in hepatoma cells. Moreover, different expression systems of marker proteins and the modes of gene transfer are discussed with emphasis on the study of lipid droplet formation in hepatocytes as an example.
Collapse
Affiliation(s)
| | | | - Jürgen Borlak
- Centre for Pharmacology and Toxicology, Hannover Medical School, Carl-Neuberg-Str, 1, 30625 Hannover, Germany.
| |
Collapse
|
35
|
Gallo E, Vasilev KV, Jarvik J. Fluorogen-activating-proteins as universal affinity biosensors for immunodetection. Biotechnol Bioeng 2014; 111:475-84. [PMID: 24122476 PMCID: PMC4334571 DOI: 10.1002/bit.25127] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2013] [Revised: 09/13/2013] [Accepted: 10/02/2013] [Indexed: 11/11/2022]
Abstract
Fluorogen-activating-proteins (FAPs) are a novel platform of fluorescence biosensors utilized for protein discovery. The technology currently demands molecular manipulation methods that limit its application and adaptability. Here, we highlight an alternative approach based on universal affinity reagents for protein detection. The affinity reagents were engineered as bi-partite fusion proteins, where the specificity moiety is derived from IgG-binding proteins-Protein A or Protein G-and the signaling element is a FAP. In this manner, primary antibodies provide the antigenic selectivity against a desired protein in biological samples, while FAP affinity reagents target the constant region (Fc) of antibodies and provide the biosensor component of detection. Fluorescence results using various techniques indicate minimal background and high target specificity for exogenous and endogenous proteins in mammalian cells. Additionally, FAP-based affinity reagents provide enhanced properties of detection previously absent using conventional affinity systems. Distinct features explored in this report include: (1) unfixed signal wavelengths (excitation and emission) determined by the particular fluorogen chosen, (2) real-time user controlled fluorescence on-set and off-set, (3) signal wavelength substitution while performing live analysis, and (4) enhanced resistance to photobleaching.
Collapse
Affiliation(s)
- Eugenio Gallo
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA 15213
| | - Kalin V. Vasilev
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA 15213
| | - Jonathan Jarvik
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA 15213
- Molecular Biosensor and Imaging Center, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA 15213
| |
Collapse
|
36
|
Fluorogen-Activating scFv Biosensors Target Surface Markers on Live Cells Via Streptavidin or Single-Chain Avidin. Mol Biotechnol 2014; 56:585-90. [DOI: 10.1007/s12033-014-9732-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
37
|
Wu Y, Tapia PH, Jarvik J, Waggoner AS, Sklar LA. Real-time detection of protein trafficking with high-throughput flow cytometry (HTFC) and fluorogen-activating protein (FAP) base biosensor. ACTA ACUST UNITED AC 2014; 67:9.43.1-9.43.11. [PMID: 24510772 DOI: 10.1002/0471142956.cy0943s67] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
We combined fluorogen-activating protein (FAP) technology with high-throughput flow cytometry to detect real-time protein trafficking to and from the plasma membrane in living cells. The hybrid platform allows drug discovery for trafficking receptors, such as G protein-coupled receptors, receptor tyrosine kinases, and ion channels, which were previously not suitable for high-throughput screening by flow cytometry. The system has been validated using the β2-adrenergic receptor (β2AR) system and extended to other GPCRs. When a chemical library containing ∼ 1200 off-patent drugs was screened against cells expressing FAP-tagged β2AR, all known β2AR active ligands in the library were successfully identified, together with a few compounds that were later confirmed to regulate receptor internalization in a nontraditional manner. The unexpected discovery of new ligands by this approach indicates the potential of using this protocol for GPCR de-orphanization. In addition, screens of multiplexed targets promise improved efficiency with minor protocol modification.
Collapse
Affiliation(s)
- Yang Wu
- Center for Molecular Discovery, University of New Mexico School of Medicine, Albuquerque, New Mexico.,Department of Pathology, University of New Mexico School of Medicine, Albuquerque, New Mexico
| | - Phillip H Tapia
- Center for Molecular Discovery, University of New Mexico School of Medicine, Albuquerque, New Mexico
| | - Jonathan Jarvik
- Department of Biological Sciences, Molecular Biosensor and Imaging Center, Carnegie Mellon University, Pittsburgh, Pennsylvania
| | - Alan S Waggoner
- Department of Biological Sciences, Molecular Biosensor and Imaging Center, Carnegie Mellon University, Pittsburgh, Pennsylvania
| | - Larry A Sklar
- Center for Molecular Discovery, University of New Mexico School of Medicine, Albuquerque, New Mexico.,Department of Pathology, University of New Mexico School of Medicine, Albuquerque, New Mexico
| |
Collapse
|
38
|
Yates BP, Peck MA, Berget PB. Directed evolution of a fluorogen-activating single chain antibody for function and enhanced brightness in the cytoplasm. Mol Biotechnol 2013; 54:829-41. [PMID: 23242633 DOI: 10.1007/s12033-012-9631-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Directed evolution is an exceptionally powerful tool that uses random mutant library generation and screening techniques to engineer or optimize functions of proteins. One class of proteins for which this process is particularly effective is antibodies, where properties such as antigen specificity and affinity can be selected to yield molecules with improved efficacy as molecular labels or in potential therapeutics. Typical antibody structure includes disulfide bonds that are required for stability and proper folding of the domains. However, these bonds are unable to form in the reducing environment of the cytoplasm, stymieing the effectiveness of optimized antibodies in many research applications. We have removed disulfide-forming cysteine residues in a single chain antibody fluorogen-activating protein (FAP), HL4, and employed directed evolution to select a derivative that is capable of activity in the cytoplasm. A subsequent round of directed evolution was targeted at increasing the overall brightness of the fluoromodule (FAP-fluorogen complex). Ultimately, this approach produced a novel FAP that exhibits strong activation of its cognate fluorogen in the reducing environment of the cytoplasm, significantly expanding the range of applications for which fluoromodule technology can be utilized.
Collapse
Affiliation(s)
- Bradley P Yates
- Department of Biological Sciences & Molecular Biosensor and Imaging Center, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, PA 15213, USA
| | | | | |
Collapse
|
39
|
Szent-Gyorgyi C, Stanfield RL, Andreko S, Dempsey A, Ahmed M, Capek S, Waggoner AS, Wilson IA, Bruchez MP. Malachite green mediates homodimerization of antibody VL domains to form a fluorescent ternary complex with singular symmetric interfaces. J Mol Biol 2013; 425:4595-613. [PMID: 23978698 DOI: 10.1016/j.jmb.2013.08.014] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2013] [Revised: 08/15/2013] [Accepted: 08/16/2013] [Indexed: 01/19/2023]
Abstract
We report that a symmetric small-molecule ligand mediates the assembly of antibody light chain variable domains (VLs) into a correspondent symmetric ternary complex with novel interfaces. The L5* fluorogen activating protein is a VL domain that binds malachite green (MG) dye to activate intense fluorescence. Crystallography of liganded L5* reveals a 2:1 protein:ligand complex with inclusive C2 symmetry, where MG is almost entirely encapsulated between an antiparallel arrangement of the two VL domains. Unliganded L5* VL domains crystallize as a similar antiparallel VL/VL homodimer. The complementarity-determining regions are spatially oriented to form novel VL/VL and VL/ligand interfaces that tightly constrain a propeller conformer of MG. Binding equilibrium analysis suggests highly cooperative assembly to form a very stable VL/MG/VL complex, such that MG behaves as a strong chemical inducer of dimerization. Fusion of two VL domains into a single protein tightens MG binding over 1000-fold to low picomolar affinity without altering the large binding enthalpy, suggesting that bonding interactions with ligand and restriction of domain movements make independent contributions to binding. Fluorescence activation of a symmetrical fluorogen provides a selection mechanism for the isolation and directed evolution of ternary complexes where unnatural symmetric binding interfaces are favored over canonical antibody interfaces. As exemplified by L5*, these self-reporting complexes may be useful as modulators of protein association or as high-affinity protein tags and capture reagents.
Collapse
Affiliation(s)
- Chris Szent-Gyorgyi
- Molecular Biosensor and Imaging Center, Carnegie Mellon University, Pittsburgh, PA 15213, USA.
| | | | | | | | | | | | | | | | | |
Collapse
|
40
|
Holleran JP, Zeng J, Frizzell RA, Watkins SC. Regulated recycling of mutant CFTR is partially restored by pharmacological treatment. J Cell Sci 2013; 126:2692-703. [PMID: 23572510 DOI: 10.1242/jcs.120196] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Efficient trafficking of the cystic fibrosis transmembrane conductance regulator (CFTR) to and from the cell surface is essential for maintaining channel density at the plasma membrane (PM) and ensuring proper physiological activity. The most common mutation, F508del, exhibits reduced surface expression and impaired function despite treatment with currently available pharmacological small molecules, called correctors. To gain more detailed insight into whether CFTR enters compartments that allow corrector stabilization in the cell periphery, we investigated the peripheral trafficking itineraries and kinetics of wild type (WT) and F508del in living cells using high-speed fluorescence microscopy together with fluorogen activating protein detection. We directly visualized internalization and accumulation of CFTR WT from the PM to a perinuclear compartment that colocalized with the endosomal recycling compartment (ERC) markers Rab11 and EHD1, reaching steady-state distribution by 25 minutes. Stimulation by protein kinase A (PKA) depleted this intracellular pool and redistributed CFTR channels to the cell surface, elicited by reduced endocytosis and active translocation to the PM. Corrector or temperature rescue of F508del also resulted in targeting to the ERC and exhibited subsequent PKA-stimulated trafficking to the PM. Corrector treatment (24 hours) led to persistent residence of F508del in the ERC, while thermally destabilized F508del was targeted to lysosomal compartments by 3 hours. Acute addition of individual correctors, C4 or C18, acted on peripheral trafficking steps to partially block lysosomal targeting of thermally destabilized F508del. Taken together, corrector treatment redirects F508del trafficking from a degradative pathway to a regulated recycling route, and proteins that mediate this process become potential targets for improving the efficacy of current and future correctors.
Collapse
Affiliation(s)
- John P Holleran
- University of Pittsburgh School of Medicine, Department of Cell Biology, BSTS 225, 3500 Terrace St, Pittsburgh, PA 15261, USA
| | | | | | | |
Collapse
|
41
|
Wu Y, Tapia PH, Fisher GW, Waggoner AS, Jarvik J, Sklar LA. High-throughput flow cytometry compatible biosensor based on fluorogen activating protein technology. Cytometry A 2013; 83:220-6. [PMID: 23303704 DOI: 10.1002/cyto.a.22242] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2012] [Revised: 09/30/2012] [Accepted: 11/20/2012] [Indexed: 12/16/2022]
Abstract
Monitoring the trafficking of multiple proteins simultaneously in live cells is of great interest because many receptor proteins are found to function together with others in the same cell. However, existing fluorescent labeling techniques have restricted the mechanistic study of functional receptor pairs. We have expanded a hybrid system combining fluorogen-activating protein (FAP) technology and high-throughput flow cytometry to a new type of biosensor that is robust, sensitive, and versatile. This provides the opportunity to study multiple trafficking proteins in the same cell. Human beta2 adrenergic receptor (β2AR) fused with FAP AM2.2 and murine C-C chemokines receptor type 5 fused with FAP MG13 was chosen for our model system. The function of the receptor and the binding between MG13 and fluorogen MG-2p have been characterized by flow cytometry and confocal microscopy assays. The binding of fluorogen and the FAP pair is highly specific, while both FAP-tagged fusion proteins function similarly to their wild-type counterparts. The system has successfully served as a counter screen assay to eliminate false positive compounds identified in a screen against NIH Molecular Libraries Small Molecule Repository targeting regulators of the human β2AR.
Collapse
Affiliation(s)
- Yang Wu
- UNM Center for Molecular Discovery, University of New Mexico School of Medicine, Albuquerque, New Mexico 87131, USA.
| | | | | | | | | | | |
Collapse
|
42
|
Shank NI, Pham HH, Waggoner AS, Armitage BA. Twisted cyanines: a non-planar fluorogenic dye with superior photostability and its use in a protein-based fluoromodule. J Am Chem Soc 2012; 135:242-51. [PMID: 23252842 DOI: 10.1021/ja308629w] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The cyanine dye thiazole orange (TO) is a well-known fluorogenic stain for DNA and RNA, but this property precludes its use as an intracellular fluorescent probe for non-nucleic acid biomolecules. Further, as is the case with many cyanines, the dye suffers from low photostability. Here, we report the synthesis of a bridge-substituted version of TO named α-CN-TO, where the central methine hydrogen of TO is replaced by an electron withdrawing cyano group, which was expected to decrease the susceptibility of the dye toward singlet oxygen-mediated degradation. An X-ray crystal structure shows that α-CN-TO is twisted drastically out of plane, in contrast to TO, which crystallizes in the planar conformation. α-CN-TO retains the fluorogenic behavior of the parent dye TO in viscous glycerol/water solvent, but direct irradiation and indirect bleaching studies showed that α-CN-TO is essentially inert to visible light and singlet oxygen. In addition, the twisted conformation of α-CN-TO mitigates nonspecific binding and fluorescence activation by DNA and a previously selected TO-binding protein and exhibits low background fluorescence in HeLa cell culture. α-CN-TO was then used to select a new protein that binds and activates fluorescence from the dye. The new α-CN-TO/protein fluoromodule exhibits superior photostability to an analogous TO/protein fluoromodule. These properties indicate that α-CN-TO will be a useful fluorogenic dye in combination with specific RNA and protein binding partners for both in vitro and cell-based applications. More broadly, structural features that promote nonplanar conformations can provide an effective method for reducing nonspecific binding of cationic dyes to nucleic acids and other biomolecules.
Collapse
Affiliation(s)
- Nathaniel I Shank
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
| | | | | | | |
Collapse
|
43
|
Bachert C, Linstedt AD. A sensor of protein O-glycosylation based on sequential processing in the Golgi apparatus. Traffic 2012; 14:47-56. [PMID: 23046148 DOI: 10.1111/tra.12019] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2012] [Revised: 10/05/2012] [Accepted: 10/09/2012] [Indexed: 12/25/2022]
Abstract
Protein O-glycosylation is important in numerous processes including the regulation of proteolytic processing sites by O-glycan masking in select newly synthesized proteins. To investigate O-glycan-mediated masking using an assay amenable to large-scale screens, we generated a fluorescent biosensor with an O-glycosylation site situated to mask a furin cleavage site. The sensor is activated when O-glycosylation fails to occur because furin cleavage releases a blocking domain allowing dye binding to a fluorogen activating protein. Thus, by design, glycosylation should block furin from activating the sensor only if it occurs first, which is predicted by the conventional view of Golgi organization. Indeed, and in contrast to the recently proposed rapid partitioning model, the sensor was non-fluorescent under normal conditions but became fluorescent when the Golgi complex was decompartmentalized. To test the utility of the sensor as a screening tool, cells expressing the sensor were exposed to a known inhibitor of O-glycosylation extension or siRNAs targeting factors known to alter glycosylation efficiency. These conditions activated the sensor substantiating its potential in identifying new inhibitors and cellular factors related to protein O-glycosylation. In summary, these findings confirm sequential processing in the Golgi, establish a new tool for studying the regulation of proteolytic processing by O-glycosylation, and demonstrate the sensor's potential usefulness for future screening projects.
Collapse
Affiliation(s)
- Collin Bachert
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | | |
Collapse
|
44
|
Holleran JP, Glover ML, Peters KW, Bertrand CA, Watkins SC, Jarvik JW, Frizzell RA. Pharmacological rescue of the mutant cystic fibrosis transmembrane conductance regulator (CFTR) detected by use of a novel fluorescence platform. Mol Med 2012; 18:685-96. [PMID: 22396015 DOI: 10.2119/molmed.2012.00001] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2012] [Accepted: 02/28/2012] [Indexed: 12/25/2022] Open
Abstract
Numerous human diseases arise because of defects in protein folding, leading to their degradation in the endoplasmic reticulum. Among them is cystic fibrosis (CF), caused by mutations in the gene encoding the CF transmembrane conductance regulator (CFTR ), an epithelial anion channel. The most common mutation, F508del, disrupts CFTR folding, which blocks its trafficking to the plasma membrane. We developed a fluorescence detection platform using fluorogen-activating proteins (FAPs) to directly detect FAP-CFTR trafficking to the cell surface using a cell-impermeant probe. By using this approach, we determined the efficacy of new corrector compounds, both alone and in combination, to rescue F508del-CFTR to the plasma membrane. Combinations of correctors produced additive or synergistic effects, improving the density of mutant CFTR at the cell surface up to ninefold over a single-compound treatment. The results correlated closely with assays of stimulated anion transport performed in polarized human bronchial epithelia that endogenously express F508del-CFTR. These findings indicate that the FAP-tagged constructs faithfully report mutant CFTR correction activity and that this approach should be useful as a screening assay in diseases that impair protein trafficking to the cell surface.
Collapse
Affiliation(s)
- John P Holleran
- Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
| | | | | | | | | | | | | |
Collapse
|
45
|
Fluorogen activating proteins in flow cytometry for the study of surface molecules and receptors. Methods 2012; 57:308-17. [PMID: 22366230 DOI: 10.1016/j.ymeth.2012.02.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2011] [Revised: 02/01/2012] [Accepted: 02/08/2012] [Indexed: 11/20/2022] Open
Abstract
The use of fluorescent proteins, particularly when genetically fused to proteins of biological interest, have greatly advanced many flow cytometry research applications. However, there remains a major limitation to this methodology in that only total cellular fluorescence is measured. Commonly used fluorescent proteins (e.g., EGFP and its variants) are fluorescent whether the fusion protein exists on the surface or in sub-cellular compartments. A flow cytometer cannot distinguish between these separate sources of fluorescence. This can be of great concern when using flow cytometry, plate readers or microscopy to quantify cell surface receptors or other surface proteins genetically fused to fluorescent proteins. Recently developed fluorogen activating proteins (FAPs) solve many of these issues by allowing the selective visualization of only those cell surface proteins that are exposed to the extracellular milieu. FAPs are GFP-sized single chain antibodies that specifically bind to and generate fluorescence from otherwise non-fluorescent dyes ('activate the fluorogen'). Like the fluorescent proteins, FAPs can be genetically fused to proteins of interest. When exogenously added fluorogens bind FAPs, fluorescence immediately increases by as much as 20,000-fold, rendering the FAP fusion proteins highly fluorescent. Moreover, since fluorogens can be made membrane impermeant, fluorescence can be limited to only those receptors expressed on the cell surface. Using cells expressing beta-2 adrenergic receptor (β2AR) fused at its N-terminus to a FAP, flow cytometry based receptor internalization assays have been developed and characterized. The fluorogen/FAP system is ideally suited to the study of cell surface proteins by fluorescence and avoids drawbacks of using receptor/fluorescent protein fusions, such as internal accumulation. We also briefly comment on extending FAP-based technologies to the study of events occurring inside of the cell as well.
Collapse
|
46
|
Abstract
Cytometric techniques are continually being improved, refined, and adapted to new applications. This chapter briefly outlines recent advances in the field of cytometry with the main focus on new instrumentations in flow and image cytometry as well as new probes suitable for multiparametric analyses. There is a remarkable trend for miniaturizing cytometers, developing label-free and fluorescence-free analytical approaches, and designing "intelligent" probes. Furthermore, new methods for analyzing complex data for extracting relevant information are reviewed.
Collapse
|