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Ivanova JR, Benk AS, Schaefer JV, Dreier B, Hermann LO, Plückthun A, Missirlis D, Spatz JP. Designed Ankyrin Repeat Proteins as Actin Labels of Distinct Cytoskeletal Structures in Living Cells. ACS NANO 2024; 18:8919-8933. [PMID: 38489155 DOI: 10.1021/acsnano.3c12265] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/17/2024]
Abstract
The orchestrated assembly of actin and actin-binding proteins into cytoskeletal structures coordinates cell morphology changes during migration, cytokinesis, and adaptation to external stimuli. The accurate and unbiased visualization of the diverse actin assemblies within cells is an ongoing challenge. We describe here the identification and use of designed ankyrin repeat proteins (DARPins) as synthetic actin binders. Actin-binding DARPins were identified through ribosome display and validated biochemically. When introduced or expressed inside living cells, fluorescently labeled DARPins accumulated at actin filaments, validated through phalloidin colocalization on fixed cells. Nevertheless, different DARPins displayed different actin labeling patterns: some DARPins labeled efficiently dynamic structures, such as filopodia, lamellipodia, and blebs, while others accumulated primarily in stress fibers. This differential intracellular distribution correlated with DARPin-actin binding kinetics, as measured by fluorescence recovery after photobleaching experiments. Moreover, the rapid arrest of actin dynamics induced by pharmacological treatment led to the fast relocalization of DARPins. Our data support the hypothesis that the localization of actin probes depends on the inherent dynamic movement of the actin cytoskeleton. Compared to the widely used LifeAct probe, one DARPin exhibited enhanced signal-to-background ratio while retaining a similar ability to label stress fibers. In summary, we propose DARPins as promising actin-binding proteins for labeling or manipulation in living cells.
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Affiliation(s)
- Julia R Ivanova
- Department of Cellular Biophysics, Max Planck Institute for Medical Research, Jahnstrasse 29, D-69120 Heidelberg, Germany
- Heidelberg University, Faculty of Biosciences, 69120 Heidelberg, Germany
- Max Planck School Matter to Life, Jahnstrasse 29, 69120 Heidelberg, Germany
| | - Amelie S Benk
- Department of Cellular Biophysics, Max Planck Institute for Medical Research, Jahnstrasse 29, D-69120 Heidelberg, Germany
| | - Jonas V Schaefer
- Department of Biochemistry, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
- CSL Behring AG, 3014 Bern, Switzerland
| | - Birgit Dreier
- Department of Biochemistry, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Leon O Hermann
- Department of Cellular Biophysics, Max Planck Institute for Medical Research, Jahnstrasse 29, D-69120 Heidelberg, Germany
| | - Andreas Plückthun
- Department of Biochemistry, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Dimitris Missirlis
- Department of Cellular Biophysics, Max Planck Institute for Medical Research, Jahnstrasse 29, D-69120 Heidelberg, Germany
- Institute for Molecular Systems Engineering and Advanced Materials, Heidelberg University, INF 225, D-69120 Heidelberg, Germany
| | - Joachim P Spatz
- Department of Cellular Biophysics, Max Planck Institute for Medical Research, Jahnstrasse 29, D-69120 Heidelberg, Germany
- Institute for Molecular Systems Engineering and Advanced Materials, Heidelberg University, INF 225, D-69120 Heidelberg, Germany
- Max Planck School Matter to Life, Jahnstrasse 29, 69120 Heidelberg, Germany
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2
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van Zwam MC, Dhar A, Bosman W, van Straaten W, Weijers S, Seta E, Joosten B, van Haren J, Palani S, van den Dries K. IntAct: A nondisruptive internal tagging strategy to study the organization and function of actin isoforms. PLoS Biol 2024; 22:e3002551. [PMID: 38466773 PMCID: PMC10957077 DOI: 10.1371/journal.pbio.3002551] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Revised: 03/21/2024] [Accepted: 02/16/2024] [Indexed: 03/13/2024] Open
Abstract
Mammals have 6 highly conserved actin isoforms with nonredundant biological functions. The molecular basis of isoform specificity, however, remains elusive due to a lack of tools. Here, we describe the development of IntAct, an internal tagging strategy to study actin isoforms in fixed and living cells. We identified a residue pair in β-actin that permits tag integration and used knock-in cell lines to demonstrate that IntAct β-actin expression and filament incorporation is indistinguishable from wild type. Furthermore, IntAct β-actin remains associated with common actin-binding proteins (ABPs) and can be targeted in living cells. We demonstrate the usability of IntAct for actin isoform investigations by showing that actin isoform-specific distribution is maintained in human cells. Lastly, we observed a variant-dependent incorporation of tagged actin variants into yeast actin patches, cables, and cytokinetic rings demonstrating cross species applicability. Together, our data indicate that IntAct is a versatile tool to study actin isoform localization, dynamics, and molecular interactions.
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Affiliation(s)
- Maxime C. van Zwam
- Department of Medical BioSciences, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Anubhav Dhar
- Department of Biochemistry, Division of Biological Sciences, Indian Institute of Science, Bangalore, India
| | - Willem Bosman
- Department of Medical BioSciences, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Wendy van Straaten
- Department of Medical BioSciences, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Suzanne Weijers
- Department of Medical BioSciences, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Emiel Seta
- Department of Medical BioSciences, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Ben Joosten
- Department of Medical BioSciences, Radboud University Medical Center, Nijmegen, the Netherlands
| | | | - Saravanan Palani
- Department of Biochemistry, Division of Biological Sciences, Indian Institute of Science, Bangalore, India
| | - Koen van den Dries
- Department of Medical BioSciences, Radboud University Medical Center, Nijmegen, the Netherlands
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Torii T, Sugimoto W, Itoh K, Kinoshita N, Gessho M, Goto T, Uehara I, Nakajima W, Budirahardja Y, Miyoshi D, Nishikata T, Tanaka N, Hirata H, Kawauchi K. Loss of p53 function promotes DNA damage-induced formation of nuclear actin filaments. Cell Death Dis 2023; 14:766. [PMID: 38001089 PMCID: PMC10674001 DOI: 10.1038/s41419-023-06310-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2023] [Revised: 11/08/2023] [Accepted: 11/15/2023] [Indexed: 11/26/2023]
Abstract
Tumor suppressor p53 plays a central role in response to DNA damage. DNA-damaging agents modulate nuclear actin dynamics, influencing cell behaviors; however, whether p53 affects the formation of nuclear actin filaments remains unclear. In this study, we found that p53 depletion promoted the formation of nuclear actin filaments in response to DNA-damaging agents, such as doxorubicin (DOXO) and etoposide (VP16). Even though the genetic probes used for the detection of nuclear actin filaments exerted a promotive effect on actin polymerization, the detected formation of nuclear actin filaments was highly dependent on both p53 depletion and DNA damage. Whilst active p53 is known to promote caspase-1 expression, the overexpression of caspase-1 reduced DNA damage-induced formation of nuclear actin filaments in p53-depleted cells. In contrast, co-treatment with DOXO and the pan-caspase inhibitor Q-VD-OPh or the caspase-1 inhibitor Z-YVAD-FMK induced the formation of nuclear actin filament formation even in cells bearing wild-type p53. These results suggest that the p53-caspase-1 axis suppresses DNA damage-induced formation of nuclear actin filaments. In addition, we found that the expression of nLifeact-GFP, the filamentous-actin-binding peptide Lifeact fused with the nuclear localization signal (NLS) and GFP, modulated the structure of nuclear actin filaments to be phalloidin-stainable in p53-depleted cells treated with the DNA-damaging agent, altering the chromatin structure and reducing the transcriptional activity. The level of phosphorylated H2AX (γH2AX), a marker of DNA damage, in these cells also reduced upon nLifeact-GFP expression, whilst details of the functional relationship between the formation of nLifeact-GFP-decorated nuclear actin filaments and DNA repair remained to be elucidated. Considering that the loss of p53 is associated with cancer progression, the results of this study raise a possibility that the artificial reinforcement of nuclear actin filaments by nLifeact-GFP may enhance the cytotoxic effect of DNA-damaging agents in aggressive cancer cells through a reduction in gene transcription.
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Affiliation(s)
- Takeru Torii
- Faculty of Frontiers of Innovative Research in Science and Technology (FIRST), Konan University, Kobe, 650-0047, Japan
| | - Wataru Sugimoto
- Faculty of Frontiers of Innovative Research in Science and Technology (FIRST), Konan University, Kobe, 650-0047, Japan
| | - Katsuhiko Itoh
- Faculty of Frontiers of Innovative Research in Science and Technology (FIRST), Konan University, Kobe, 650-0047, Japan
| | - Natsuki Kinoshita
- Faculty of Frontiers of Innovative Research in Science and Technology (FIRST), Konan University, Kobe, 650-0047, Japan
| | - Masaya Gessho
- Faculty of Frontiers of Innovative Research in Science and Technology (FIRST), Konan University, Kobe, 650-0047, Japan
| | - Toshiyuki Goto
- Faculty of Frontiers of Innovative Research in Science and Technology (FIRST), Konan University, Kobe, 650-0047, Japan
| | - Ikuno Uehara
- Department of Molecular Oncology, Institute for Advanced Medical Sciences, Nippon Medical School, Tokyo, 113-8602, Japan
| | - Wataru Nakajima
- Department of Molecular Oncology, Institute for Advanced Medical Sciences, Nippon Medical School, Tokyo, 113-8602, Japan
| | - Yemima Budirahardja
- Faculty of Frontiers of Innovative Research in Science and Technology (FIRST), Konan University, Kobe, 650-0047, Japan
| | - Daisuke Miyoshi
- Faculty of Frontiers of Innovative Research in Science and Technology (FIRST), Konan University, Kobe, 650-0047, Japan
| | - Takahito Nishikata
- Faculty of Frontiers of Innovative Research in Science and Technology (FIRST), Konan University, Kobe, 650-0047, Japan
| | - Nobuyuki Tanaka
- Department of Molecular Oncology, Institute for Advanced Medical Sciences, Nippon Medical School, Tokyo, 113-8602, Japan
| | - Hiroaki Hirata
- Department of Applied Bioscience, Kanazawa Institute of Technology, Hakusan, 924-0838, Japan.
| | - Keiko Kawauchi
- Faculty of Frontiers of Innovative Research in Science and Technology (FIRST), Konan University, Kobe, 650-0047, Japan.
- Department of Molecular Oncology, Institute for Advanced Medical Sciences, Nippon Medical School, Tokyo, 113-8602, Japan.
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Kawanishi T, Heilig AK, Shimada A, Takeda H. Visualization of Actin Cytoskeleton in Cellular Protrusions in Medaka Embryos. Bio Protoc 2023; 13:e4710. [PMID: 37449037 PMCID: PMC10336567 DOI: 10.21769/bioprotoc.4710] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Revised: 03/13/2023] [Accepted: 04/23/2023] [Indexed: 07/18/2023] Open
Abstract
Cellular protrusions are fundamental structures for a wide variety of cellular behaviors, such as cell migration, cell-cell interaction, and signal reception. Visualization of cellular protrusions in living cells can be achieved by labeling of cytoskeletal actin with genetically encoded fluorescent probes. Here, we describe a detailed experimental procedure to visualize cellular protrusions in medaka embryos, which consists of the following steps: preparation of Actin-Chromobody-GFP and α-bungarotoxin mRNAs for actin labeling and immobilization of the embryo, respectively; microinjection of the mRNAs into embryos in a mosaic fashion to sparsely label individual cells; removal of the hard chorion, which hampers observation; and visualization of cellular protrusions in the embryo with a confocal microscope. Overall, our protocol provides a simple method to reveal cellular protrusions in vivo by confocal microscopy.
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Affiliation(s)
- Toru Kawanishi
- Department of Biological Sciences, Graduate School of Science, University of Tokyo, Tokyo, Japan
| | - Ann Kathrin Heilig
- Department of Biological Sciences, Graduate School of Science, University of Tokyo, Tokyo, Japan
| | - Atsuko Shimada
- Department of Biological Sciences, Graduate School of Science, University of Tokyo, Tokyo, Japan
| | - Hiroyuki Takeda
- Department of Biological Sciences, Graduate School of Science, University of Tokyo, Tokyo, Japan
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5
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Ignácz A, Nagy-Herczeg D, Hausser A, Schlett K. Dendritic effects of genetically encoded actin-labeling probes in cultured hippocampal neurons. Mol Biol Cell 2023; 34:br8. [PMID: 36989034 PMCID: PMC10295473 DOI: 10.1091/mbc.e22-08-0331] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Revised: 03/14/2023] [Accepted: 03/20/2023] [Indexed: 03/30/2023] Open
Abstract
Actin cytoskeleton predominantly regulates the formation and maintenance of synapses by controlling dendritic spine morphology and motility. To visualize actin dynamics, actin molecules can be labeled by genetically fusing fluorescent proteins to actin monomers, actin-binding proteins, or single-chain anti-actin antibodies. In the present study, we compared the dendritic effect of EGFP-actin, LifeAct-TagGFP2 (LifeAct-GFP), and Actin-Chromobody-TagGFP2 (AC-GFP) in mouse cultured hippocampal neurons using unbiased quantitative methods. The actin-binding probes LifeAct-GFP and AC-GFP showed similar affinity to F-actin, but in contrast to EGFP-actin, they did not reveal subtle changes in actin remodeling between mushroom-shaped spines and filopodia. All tested actin probes colocalized with phalloidin similarly; however, the enrichment of LifeAct-GFP in dendritic spines was remarkably lower compared with the other constructs. LifeAct-GFP expression was tolerated at a higher expression level compared with EGFP-actin and AC-GFP with only subtle differences identified in dendritic spine morphology and protrusion density. While EGFP-actin and LifeAct-GFP expression did not alter dendritic arborization, AC-GFP-expressing neurons displayed a reduced dendritic tree. Thus, although all tested actin probes may be suitable for actin imaging studies, certain limitations should be considered before performing experiments with a particular actin-labeling probe in primary neurons.
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Affiliation(s)
- Attila Ignácz
- Department of Physiology and Neurobiology, Eötvös Loránd University, Budapest, Hungary
| | - Domonkos Nagy-Herczeg
- Department of Physiology and Neurobiology, Eötvös Loránd University, Budapest, Hungary
| | - Angelika Hausser
- Institute of Cell Biology and Immunology, University of Stuttgart, Stuttgart, Germany
- Stuttgart Research Center Systems Biology, University of Stuttgart, Stuttgart, Germany
| | - Katalin Schlett
- Department of Physiology and Neurobiology, Eötvös Loránd University, Budapest, Hungary
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Oda H, Sato Y, Kawashima SA, Fujiwara Y, Pálfy M, Wu E, Vastenhouw NL, Kanai M, Kimura H. Actin filaments accumulated in the nucleus remain in the vicinity of condensing chromosomes in the zebrafish early embryo. Biol Open 2023; 12:bio059783. [PMID: 37071022 PMCID: PMC10214854 DOI: 10.1242/bio.059783] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Accepted: 03/30/2023] [Indexed: 04/19/2023] Open
Abstract
In the cytoplasm, filamentous actin (F-actin) plays a critical role in cell regulation, including cell migration, stress fiber formation, and cytokinesis. Recent studies have shown that actin filaments that form in the nucleus are associated with diverse functions. Here, using live imaging of an F-actin-specific probe, superfolder GFP-tagged utrophin (UtrCH-sfGFP), we demonstrated the dynamics of nuclear actin in zebrafish (Danio rerio) embryos. In early zebrafish embryos up to around the high stage, UtrCH-sfGFP increasingly accumulated in nuclei during the interphase and reached a peak during the prophase. After nuclear envelope breakdown (NEBD), patches of UtrCH-sfGFP remained in the vicinity of condensing chromosomes during the prometaphase to metaphase. When zygotic transcription was inhibited by injecting α-amanitin, the nuclear accumulation of UtrCH-sfGFP was still observed at the sphere and dome stages, suggesting that zygotic transcription may induce a decrease in nuclear F-actin. The accumulation of F-actin in nuclei may contribute to proper mitotic progression of large cells with rapid cell cycles in zebrafish early embryos, by assisting in NEBD, chromosome congression, and/or spindle assembly.
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Affiliation(s)
- Haruka Oda
- Cell Biology Center, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama 226-8503, Japan
| | - Yuko Sato
- Cell Biology Center, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama 226-8503, Japan
| | - Shigehiro A. Kawashima
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo 113-0033, Japan
| | - Yusuke Fujiwara
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo 113-0033, Japan
| | - Máté Pálfy
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden-01307, Germany
| | - Edlyn Wu
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden-01307, Germany
- University of Lausanne, Center for Integrative Genomics, Lausanne 1015, Switzerland
| | - Nadine L. Vastenhouw
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden-01307, Germany
- University of Lausanne, Center for Integrative Genomics, Lausanne 1015, Switzerland
| | - Motomu Kanai
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo 113-0033, Japan
| | - Hiroshi Kimura
- Cell Biology Center, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama 226-8503, Japan
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Yee M, Walther T, Frischknecht F, Douglas RG. Divergent Plasmodium actin residues are essential for filament localization, mosquito salivary gland invasion and malaria transmission. PLoS Pathog 2022; 18:e1010779. [PMID: 35998188 PMCID: PMC9439217 DOI: 10.1371/journal.ppat.1010779] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Revised: 09/02/2022] [Accepted: 07/29/2022] [Indexed: 11/18/2022] Open
Abstract
Actin is one of the most conserved and ubiquitous proteins in eukaryotes. Its sequence has been highly conserved for its monomers to self-assemble into filaments that mediate essential cell functions such as trafficking, cell shape and motility. The malaria-causing parasite, Plasmodium, expresses a highly sequence divergent actin that is critical for its rapid motility at different stages within its mammalian and mosquito hosts. Each of Plasmodium actin’s four subdomains have divergent regions compared to canonical vertebrate actins. We previously identified subdomains 2 and 3 as providing critical contributions for parasite actin function as these regions could not be replaced by subdomains of vertebrate actins. Here we probed the contributions of individual divergent amino acid residues in these subdomains on parasite motility and progression. Non-lethal changes in these subdomains did not affect parasite development in the mammalian host but strongly affected progression through the mosquito with striking differences in transmission to and through the insect. Live visualization of actin filaments showed that divergent amino acid residues in subdomains 2 and 4 enhanced localization associated with filaments, while those in subdomain 3 negatively affected actin filaments. This suggests that finely tuned actin dynamics are essential for efficient organ entry in the mosquito vector affecting malaria transmission. This work provides residue level insight on the fundamental requirements of actin in highly motile cells. Actin is one of the most abundant and conserved proteins known. Actin monomers can join together to form long filaments. The malaria-causing parasite is transmitted by mosquitoes and needs actin to move very rapidly. An actin from the parasite is different to other actins: its amino acid sequence has relatively high amounts of changes compared to animal species and the actin tends to form only short filaments. We previously identified two large parts of the protein that were critical for the parasite since these large parts could not be exchanged with the equivalent regions of other species. In this study, we focused in on these regions by making more discrete mutations. Most mutations of the actin sequence were tolerated by the parasite in the blood stages. However, these mutants has striking defects in progressing through mosquitoes, especially in invading its salivary glands. We used a new filament labeler to visualize how these mutations affect the actin filaments and found surprisingly different effects. Taken together, small changes to the sequence can have large consequences for the parasite, which ultimately affects its ability to transmit to a new host.
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Affiliation(s)
- Michelle Yee
- Integrative Parasitology, Center for Infectious Diseases, Heidelberg University Medical School, Heidelberg, Germany
| | - Tobias Walther
- Integrative Parasitology, Center for Infectious Diseases, Heidelberg University Medical School, Heidelberg, Germany
| | - Friedrich Frischknecht
- Integrative Parasitology, Center for Infectious Diseases, Heidelberg University Medical School, Heidelberg, Germany
- German Centre for Infection Research, DZIF, partner site Heidelberg, Heidelberg, Germany
- * E-mail: (FF); (RGD)
| | - Ross G. Douglas
- Integrative Parasitology, Center for Infectious Diseases, Heidelberg University Medical School, Heidelberg, Germany
- Biochemistry and Molecular Biology, Interdisciplinary Research Centre and Molecular Infection Biology, Biomedical Research Centre Seltersberg, Justus Liebig University Giessen, Giessen, Germany
- * E-mail: (FF); (RGD)
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Pain C, Tolmie F, Wojcik S, Wang P, Kriechbaumer V. intER-ACTINg: the structure and dynamics of ER and actin are interlinked. J Microsc 2022. [PMID: 35985796 DOI: 10.1111/jmi.13139] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Revised: 08/09/2022] [Accepted: 08/10/2022] [Indexed: 11/30/2022]
Abstract
The actin cytoskeleton is the driver of gross ER remodelling and the movement and positioning of other membrane-bound organelles such as Golgi bodies. Rapid ER membrane remodelling is a feature of most plant cells and is important for normal cellular processes, including targeted secretion, immunity and signalling. Modifications to the actin cytoskeleton, through pharmacological agents such as Latrunculin B and phalloidin, or disruption of normal myosin function also affect ER structure and/or dynamics. Here, we investigate the impact of changes in the actin cytoskeleton on structure and dynamics on the ER as well as in return the impact of modified ER structure on the architecture of the actin cytoskeleton. By expressing actin markers that affect actin dynamics, or expressing of ER-shaping proteins that influence ER architecture, we found that the structure of ER-actin networks is closely inter-related; affecting one component is likely to have a direct effect on the other. Therefore, our results indicate that a complicated regulatory machinery and cross-talk between these two structures must exist in plants to co-ordinate the function of ER-actin network during multiple subcellular processes. In addition, when considering organelle structure and dynamics, the choice of actin marker is essential in preventing off-target organelle structure and dynamics modifications. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Charlotte Pain
- Plant Cell Biology, Department of Biological and Medical Sciences, Oxford Brookes University, Oxford, OX3 0BP, UK
| | - Frances Tolmie
- Plant Cell Biology, Department of Biological and Medical Sciences, Oxford Brookes University, Oxford, OX3 0BP, UK
| | - Stefan Wojcik
- Plant Cell Biology, Department of Biological and Medical Sciences, Oxford Brookes University, Oxford, OX3 0BP, UK
| | - Pengwei Wang
- Key Laboratory of Horticultural Plant Biology (Ministry of Education), College of Horticulture and Forestry Science, Huazhong Agricultural University, Wuhan, 430070, China
| | - Verena Kriechbaumer
- Plant Cell Biology, Department of Biological and Medical Sciences, Oxford Brookes University, Oxford, OX3 0BP, UK
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Cordell P, Carrington G, Curd A, Parker F, Tomlinson D, Peckham M. Affimers and nanobodies as molecular probes and their applications in imaging. J Cell Sci 2022; 135:276020. [PMID: 35848463 PMCID: PMC9450889 DOI: 10.1242/jcs.259168] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Antibodies are the most widely used, traditional tool for labelling molecules in cells. In the past five to ten years, many new labelling tools have been developed with significant advantages over the traditional antibody. Here, we focus on nanobodies and the non-antibody binding scaffold proteins called Affimers. We explain how they are generated, selected and produced, and we describe how their small size, high binding affinity and specificity provides them with many advantages compared to antibodies. Of particular importance, their small size enables them to better penetrate dense cytoskeletal regions within cells, as well as tissues, providing them with specific advantage for super-resolution imaging, as they place the fluorophore with a few nanometres of the target protein being imaged. We expect these novel tools to be of broad interest to many cell biologists and anticipate them becoming the tools of choice for super-resolution imaging.
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Wagner TR, Rothbauer U. Nanobodies - Little helpers unravelling intracellular signaling. Free Radic Biol Med 2021; 176:46-61. [PMID: 34536541 DOI: 10.1016/j.freeradbiomed.2021.09.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Revised: 08/26/2021] [Accepted: 09/08/2021] [Indexed: 11/21/2022]
Abstract
The identification of diagnostic and therapeutic targets requires a comprehensive understanding of cellular processes, for which advanced technologies in biomedical research are needed. The emergence of nanobodies (Nbs) derived from antibody fragments of camelid heavy chain-only antibodies as intracellular research tools offers new possibilities to study and modulate target antigens in living cells. Here we summarize this rapidly changing field, beginning with a brief introduction of Nbs, followed by an overview of how target-specific Nbs can be generated, and introduce the selection of intrabodies as research tools. Intrabodies, by definition, are intracellular functional Nbs that target ectopic or endogenous intracellular antigens within living cells. Such binders can be applied in various formats, e.g. as chromobodies for live cell microscopy or as biosensors to decipher complex intracellular signaling pathways. In addition, protein knockouts can be achieved by target-specific Nbs, while modulating Nbs have the potential as future therapeutics. The development of fine-tunable and switchable Nb-based systems that simultaneously provide spatial and temporal control has recently taken the application of these binders to the next level.
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Affiliation(s)
- Teresa R Wagner
- Pharmaceutical Biotechnology, Eberhard Karls University, Tübingen, Germany; NMI Natural and Medical Sciences Institute at the University of Tübingen, Reutlingen, Germany
| | - Ulrich Rothbauer
- Pharmaceutical Biotechnology, Eberhard Karls University, Tübingen, Germany; NMI Natural and Medical Sciences Institute at the University of Tübingen, Reutlingen, Germany; Cluster of Excellence iFIT (EXC2180) "Image-Guided and Functionally Instructed Tumor Therapies", Eberhard Karls University, Tübingen, Germany.
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11
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Xu R, Du S. Overexpression of Lifeact-GFP Disrupts F-Actin Organization in Cardiomyocytes and Impairs Cardiac Function. Front Cell Dev Biol 2021; 9:746818. [PMID: 34765602 PMCID: PMC8576398 DOI: 10.3389/fcell.2021.746818] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2021] [Accepted: 10/07/2021] [Indexed: 11/28/2022] Open
Abstract
Lifeact-GFP is a frequently used molecular probe to study F-actin structure and dynamic assembly in living cells. In this study, we generated transgenic zebrafish models expressing Lifeact-GFP specifically in cardiac muscles to investigate the effect of Lifeact-GFP on heart development and its application to study cardiomyopathy. The data showed that transgenic zebrafish with low to moderate levels of Lifeact-GFP expression could be used as a good model to study contractile dynamics of actin filaments in cardiac muscles in vivo. Using this model, we demonstrated that loss of Smyd1b, a lysine methyltransferase, disrupted F-actin filament organization in cardiomyocytes of zebrafish embryos. Our studies, however, also demonstrated that strong Lifeact-GFP expression in cardiomyocytes was detrimental to actin filament organization in cardiomyocytes that led to pericardial edema and early embryonic lethality of zebrafish embryos. Collectively, these data suggest that although Lifeact-GFP is a good probe for visualizing F-actin dynamics, transgenic models need to be carefully evaluated to avoid artifacts induced by Lifeact-GFP overexpression.
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Affiliation(s)
| | - Shaojun Du
- Department of Biochemistry and Molecular Biology, Institute of Marine and Environmental Technology, University of Maryland School of Medicine, Baltimore, MD, United States
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12
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Savage Z, Duggan C, Toufexi A, Pandey P, Liang Y, Segretin ME, Yuen LH, Gaboriau DCA, Leary AY, Tumtas Y, Khandare V, Ward AD, Botchway SW, Bateman BC, Pan I, Schattat M, Sparkes I, Bozkurt TO. Chloroplasts alter their morphology and accumulate at the pathogen interface during infection by Phytophthora infestans. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2021; 107:1771-1787. [PMID: 34250673 DOI: 10.1111/tpj.15416] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 07/02/2021] [Accepted: 07/08/2021] [Indexed: 05/22/2023]
Abstract
Upon immune activation, chloroplasts switch off photosynthesis, produce antimicrobial compounds and associate with the nucleus through tubular extensions called stromules. Although it is well established that chloroplasts alter their position in response to light, little is known about the dynamics of chloroplast movement in response to pathogen attack. Here, we report that during infection with the Irish potato famine pathogen Phytophthora infestans, chloroplasts accumulate at the pathogen interface, associating with the specialized membrane that engulfs the pathogen haustorium. The chemical inhibition of actin polymerization reduces the accumulation of chloroplasts at pathogen haustoria, suggesting that this process is partially dependent on the actin cytoskeleton. However, chloroplast accumulation at haustoria does not necessarily rely on movement of the nucleus to this interface and is not affected by light conditions. Stromules are typically induced during infection, embracing haustoria and facilitating chloroplast interactions, to form dynamic organelle clusters. We found that infection-triggered stromule formation relies on BRASSINOSTEROID INSENSITIVE 1-ASSOCIATED KINASE 1 (BAK1)-mediated surface immune signaling, whereas chloroplast repositioning towards haustoria does not. Consistent with the defense-related induction of stromules, effector-mediated suppression of BAK1-mediated immune signaling reduced stromule formation during infection. On the other hand, immune recognition of the same effector stimulated stromules, presumably via a different pathway. These findings implicate chloroplasts in a polarized response upon pathogen attack and point to more complex functions of these organelles in plant-pathogen interactions.
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Affiliation(s)
- Zachary Savage
- Department of Life Sciences, Imperial College London, Imperial College Road, South Kensington Campus, London, London, SW7 2AZ, UK
| | - Cian Duggan
- Department of Life Sciences, Imperial College London, Imperial College Road, South Kensington Campus, London, London, SW7 2AZ, UK
| | - Alexia Toufexi
- Department of Life Sciences, Imperial College London, Imperial College Road, South Kensington Campus, London, London, SW7 2AZ, UK
| | - Pooja Pandey
- Department of Life Sciences, Imperial College London, Imperial College Road, South Kensington Campus, London, London, SW7 2AZ, UK
| | - Yuxi Liang
- Department of Life Sciences, Imperial College London, Imperial College Road, South Kensington Campus, London, London, SW7 2AZ, UK
| | - María Eugenia Segretin
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular 'Dr Héctor N. Torres' (INGEBI)-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Vuelta de Obligado 2490, Ciudad Autónoma de Buenos Aires, C1428ADN, Argentina
| | - Lok Him Yuen
- Department of Life Sciences, Imperial College London, Imperial College Road, South Kensington Campus, London, London, SW7 2AZ, UK
| | - David C A Gaboriau
- Facility for Imaging by Light Microscopy, Faculty of Medicine, National Heart & Lung Institute (NHLI), Imperial College London, South Kensington, SAF building, London, SW7 2AZ, UK
| | - Alexandre Y Leary
- Department of Life Sciences, Imperial College London, Imperial College Road, South Kensington Campus, London, London, SW7 2AZ, UK
| | - Yasin Tumtas
- Department of Life Sciences, Imperial College London, Imperial College Road, South Kensington Campus, London, London, SW7 2AZ, UK
| | - Virendrasinh Khandare
- Department of Life Sciences, Imperial College London, Imperial College Road, South Kensington Campus, London, London, SW7 2AZ, UK
| | - Andrew D Ward
- Central Laser Facility, Science and Technology Facilities Council Harwell, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Harwell, Didcot, OX11 0QX, UK
| | - Stanley W Botchway
- Central Laser Facility, Science and Technology Facilities Council Harwell, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Harwell, Didcot, OX11 0QX, UK
| | - Benji C Bateman
- Central Laser Facility, Science and Technology Facilities Council Harwell, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Harwell, Didcot, OX11 0QX, UK
| | - Indranil Pan
- Centre for Process Systems Engineering and Centre for Environmental Policy, Imperial College London, South Kensington Campus, London, London, SW7 2AZ, UK
- The Alan Turing Institute, British Library, 96 Euston Road, London, London, NW1 2DB, UK
| | - Martin Schattat
- Martin Luther Universität Halle-Wittenberg, Halle, 06108 Halle, Germany
| | - Imogen Sparkes
- School of Biological Sciences, University of Bristol, University of Bristol, St Michael's Hill, Bristol, BS8 8DZ, UK
| | - Tolga O Bozkurt
- Department of Life Sciences, Imperial College London, Imperial College Road, South Kensington Campus, London, London, SW7 2AZ, UK
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13
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Nakai N, Sato K, Tani T, Kawagishi M, Ka H, Saito K, Terada S. Development of nanobody-based POLArIS orientation probes enabled multi-color/multi-target orientation imaging in living cells. Biochem Biophys Res Commun 2021; 565:50-56. [PMID: 34090210 DOI: 10.1016/j.bbrc.2021.05.088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Accepted: 05/26/2021] [Indexed: 10/21/2022]
Abstract
Fluorescence polarization microscopy (FPM) can visualize the dipole orientation of fluorescent molecules and has been used for analyzing architectural dynamics of biomolecules including cytoskeletal proteins. To monitor the orientation of target molecules by FPM, target molecules need to be labeled with fluorophores in a sterically constrained manner, so that the fluorophores do not freely rotate. Recently, a versatile probe for such labeling using fluorescent proteins, POLArIS (Probe for Orientation and Localization Assessment, recognizing specific Intracellular Structures of interest), was reported. POLArIS is a fusion protein consisting of a non-immunoglobulin-based recombinant binder Affimer and a green fluorescent protein (GFP), where the Affimer and GFP are rigidly connected to each other. POLArIS probe for molecules of interest can be developed through phage display screening of Affimer. This screening is followed by the rigid connection of fluorescent proteins to the selected Affimers. The Affimer-based POLArIS, however, cannot be used with animal immune libraries for selecting specific binder clones. In addition, multi-color FPM by POLArIS was not available due to the lack of color variations of POLArIS. In this study, we have developed new versions of POLArIS with nanobodies, which are compatible with animal immune libraries, and expanded color variations of POLArIS with cyan/green/yellow/red fluorescent proteins, enabling multi-color orientation imaging for multiple targets. Using nanobody-based POLArIS orientation probes, we performed two-color FPM of F-actin and vimentin in living cells. Furthermore, we made nanobody-based POLArIS probes that have different dipole orientations for adjusting the orientation of fluorescence polarization with respect to the target molecules. These nanobody-based POLArIS with options of colors and dipole orientations will enhance the performance of this probe for broader applications of fluorescence polarization imaging in living cells, tissues, and whole organisms.
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Affiliation(s)
- Nori Nakai
- Department of Neuroanatomy and Cellular Neurobiology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Bunkyo-ku, Tokyo, 113-8519, Japan; Center for Brain Integration Research, TMDU, Bunkyo-ku, Tokyo, 113-8519, Japan.
| | - Keisuke Sato
- Department of Neuroanatomy and Cellular Neurobiology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Bunkyo-ku, Tokyo, 113-8519, Japan; Center for Brain Integration Research, TMDU, Bunkyo-ku, Tokyo, 113-8519, Japan.
| | - Tomomi Tani
- Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology, Ikeda, Osaka, 563-8577, Japan.
| | - Masahiko Kawagishi
- Department of Neuroanatomy and Cellular Neurobiology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Bunkyo-ku, Tokyo, 113-8519, Japan; Center for Brain Integration Research, TMDU, Bunkyo-ku, Tokyo, 113-8519, Japan.
| | - Hiromasa Ka
- Department of Neuroanatomy and Cellular Neurobiology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Bunkyo-ku, Tokyo, 113-8519, Japan; Center for Brain Integration Research, TMDU, Bunkyo-ku, Tokyo, 113-8519, Japan.
| | - Kenta Saito
- Department of Neuroanatomy and Cellular Neurobiology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Bunkyo-ku, Tokyo, 113-8519, Japan; Center for Brain Integration Research, TMDU, Bunkyo-ku, Tokyo, 113-8519, Japan.
| | - Sumio Terada
- Department of Neuroanatomy and Cellular Neurobiology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Bunkyo-ku, Tokyo, 113-8519, Japan; Center for Brain Integration Research, TMDU, Bunkyo-ku, Tokyo, 113-8519, Japan.
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14
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Das S, Stortz JF, Meissner M, Periz J. The multiple functions of actin in apicomplexan parasites. Cell Microbiol 2021; 23:e13345. [PMID: 33885206 DOI: 10.1111/cmi.13345] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 03/30/2021] [Accepted: 03/31/2021] [Indexed: 11/29/2022]
Abstract
The cytoskeletal protein actin is highly abundant and conserved in eukaryotic cells. It occurs in two different states- the globular (G-actin) form, which can polymerise into the filamentous (F-actin) form, fulfilling various critical functions including cytokinesis, cargo trafficking and cellular motility. In higher eukaryotes, there are several actin isoforms with nearly identical amino acid sequences. Despite the high level of amino acid identity, they display regulated expression patterns and unique non-redundant roles. The number of actin isoforms together with conserved sequences may reflect the selective pressure exerted by scores of actin binding proteins (ABPs) in higher eukaryotes. In contrast, in many protozoans such as apicomplexan parasites which possess only a few ABPs, the regulatory control of actin and its multiple functions are still obscure. Here, we provide a summary of the regulation and biological functions of actin in higher eukaryotes and compare it with the current knowledge in apicomplexans. We discuss future experiments that will help us understand the multiple, critical roles of this fascinating system in apicomplexans.
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Affiliation(s)
- Sujaan Das
- Faculty of Veterinary Medicine, Experimental Parasitology, Ludwig Maximilian University, Munich, Germany
| | - Johannes Felix Stortz
- Department Metabolism of Infection, Max Planck Institute for Biology of Ageing, Cologne, Germany
| | - Markus Meissner
- Faculty of Veterinary Medicine, Experimental Parasitology, Ludwig Maximilian University, Munich, Germany
| | - Javier Periz
- Faculty of Veterinary Medicine, Experimental Parasitology, Ludwig Maximilian University, Munich, Germany
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15
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Mazloom-Farsibaf H, Farzam F, Fazel M, Wester MJ, Meddens MBM, Lidke KA. Comparing lifeact and phalloidin for super-resolution imaging of actin in fixed cells. PLoS One 2021; 16:e0246138. [PMID: 33508018 PMCID: PMC7842966 DOI: 10.1371/journal.pone.0246138] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Accepted: 01/13/2021] [Indexed: 01/14/2023] Open
Abstract
Visualizing actin filaments in fixed cells is of great interest for a variety of topics in cell biology such as cell division, cell movement, and cell signaling. We investigated the possibility of replacing phalloidin, the standard reagent for super-resolution imaging of F-actin in fixed cells, with the actin binding peptide 'lifeact'. We compared the labels for use in single molecule based super-resolution microscopy, where AlexaFluor 647 labeled phalloidin was used in a dSTORM modality and Atto 655 labeled lifeact was used in a single molecule imaging, reversible binding modality. We found that imaging with lifeact had a comparable resolution in reconstructed images and provided several advantages over phalloidin including lower costs, the ability to image multiple regions of interest on a coverslip without degradation, simplified sequential super-resolution imaging, and more continuous labeling of thin filaments.
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Affiliation(s)
- Hanieh Mazloom-Farsibaf
- Department of Physics and Astronomy, University of New Mexico, Albuquerque, New Mexico, United States of America
| | - Farzin Farzam
- Department of Physics and Astronomy, University of New Mexico, Albuquerque, New Mexico, United States of America
| | - Mohamadreza Fazel
- Department of Physics and Astronomy, University of New Mexico, Albuquerque, New Mexico, United States of America
| | - Michael J Wester
- Department of Physics and Astronomy, University of New Mexico, Albuquerque, New Mexico, United States of America
- Department of Mathematics and Statistics, University of New Mexico, Albuquerque, New Mexico, United States of America
| | - Marjolein B M Meddens
- Department of Physics and Astronomy, University of New Mexico, Albuquerque, New Mexico, United States of America
| | - Keith A Lidke
- Department of Physics and Astronomy, University of New Mexico, Albuquerque, New Mexico, United States of America
- Comprehensive Cancer Center, University of New Mexico, Albuquerque, New Mexico, United States of America
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16
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Schneider F, Colin-York H, Fritzsche M. Quantitative Bio-Imaging Tools to Dissect the Interplay of Membrane and Cytoskeletal Actin Dynamics in Immune Cells. Front Immunol 2021; 11:612542. [PMID: 33505401 PMCID: PMC7829180 DOI: 10.3389/fimmu.2020.612542] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Accepted: 11/23/2020] [Indexed: 12/13/2022] Open
Abstract
Cellular function is reliant on the dynamic interplay between the plasma membrane and the actin cytoskeleton. This critical relationship is of particular importance in immune cells, where both the cytoskeleton and the plasma membrane work in concert to organize and potentiate immune signaling events. Despite their importance, there remains a critical gap in understanding how these respective dynamics are coupled, and how this coupling in turn may influence immune cell function from the bottom up. In this review, we highlight recent optical technologies that could provide strategies to investigate the simultaneous dynamics of both the cytoskeleton and membrane as well as their interplay, focusing on current and future applications in immune cells. We provide a guide of the spatio-temporal scale of each technique as well as highlighting novel probes and labels that have the potential to provide insights into membrane and cytoskeletal dynamics. The quantitative biophysical tools presented here provide a new and exciting route to uncover the relationship between plasma membrane and cytoskeletal dynamics that underlies immune cell function.
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Affiliation(s)
- Falk Schneider
- Medical Research Council (MRC) Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, United Kingdom
| | - Huw Colin-York
- Medical Research Council (MRC) Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, United Kingdom
- Kennedy Institute for Rheumatology, University of Oxford, Oxford, United Kingdom
| | - Marco Fritzsche
- Medical Research Council (MRC) Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, United Kingdom
- Kennedy Institute for Rheumatology, University of Oxford, Oxford, United Kingdom
- Rosalind Franklin Institute, Harwell Campus, Didcot, United Kingdom
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17
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Wang W, Yuan J, Jiang C. Applications of nanobodies in plant science and biotechnology. PLANT MOLECULAR BIOLOGY 2021; 105:43-53. [PMID: 33037986 PMCID: PMC7547553 DOI: 10.1007/s11103-020-01082-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2020] [Accepted: 10/05/2020] [Indexed: 05/15/2023]
Abstract
Present review summarizes the current applications of nanobodies in plant science and biotechnology, including plant expression of nanobodies, plant biotechnological applications, nanobody-based immunodetection, and nanobody-mediated resistance against plant pathogens. Nanobodies (Nbs) are variable domains of heavy chain-only antibodies (HCAbs) isolated from camelids. In spite of their single domain structure, nanobodies display many unique features, such as small size, high stability, and cryptic epitopes accessibility, which make them ideal for sophisticated applications in plants and animals. In this review, we summarize the current applications of nanobodies in plant science and biotechnology, focusing on nanobody expression in plants, plant biotechnological applications, determination of plant toxins and pathogens, and nanobody-mediated resistance against plant pathogens. Prospects and challenges of nanobody applications in plants are also discussed.
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Affiliation(s)
- Wenyi Wang
- Institute for Medical Biology and Hubei Provincial Key Laboratory for Protection and Application of Special Plants in Wuling Area of China, College of Life Sciences, South-Central University for Nationalities, Wuhan, Hubei, China.
- Precision Medicine R&D Center, Zhuhai Institute of Advanced Technology, Chinese Academy of Sciences, Zhuhai, Guangdong Province, China.
- Institute of Biomedicine and Biotechnology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, Guangdong Province, China.
| | - Jumao Yuan
- Precision Medicine R&D Center, Zhuhai Institute of Advanced Technology, Chinese Academy of Sciences, Zhuhai, Guangdong Province, China
- Institute of Biomedicine and Biotechnology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, Guangdong Province, China
| | - Changan Jiang
- Precision Medicine R&D Center, Zhuhai Institute of Advanced Technology, Chinese Academy of Sciences, Zhuhai, Guangdong Province, China
- Institute of Biomedicine and Biotechnology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, Guangdong Province, China
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18
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Smith CEL, Lake AVR, Johnson CA. Primary Cilia, Ciliogenesis and the Actin Cytoskeleton: A Little Less Resorption, A Little More Actin Please. Front Cell Dev Biol 2020; 8:622822. [PMID: 33392209 PMCID: PMC7773788 DOI: 10.3389/fcell.2020.622822] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Accepted: 11/24/2020] [Indexed: 12/13/2022] Open
Abstract
Primary cilia are microtubule-based organelles that extend from the apical surface of most mammalian cells, forming when the basal body (derived from the mother centriole) docks at the apical cell membrane. They act as universal cellular "antennae" in vertebrates that receive and integrate mechanical and chemical signals from the extracellular environment, serving diverse roles in chemo-, mechano- and photo-sensation that control developmental signaling, cell polarity and cell proliferation. Mutations in ciliary genes cause a major group of inherited developmental disorders called ciliopathies. There are very few preventative treatments or new therapeutic interventions that modify disease progression or the long-term outlook of patients with these conditions. Recent work has identified at least four distinct but interrelated cellular processes that regulate cilia formation and maintenance, comprising the cell cycle, cellular proteostasis, signaling pathways and structural influences of the actin cytoskeleton. The actin cytoskeleton is composed of microfilaments that are formed from filamentous (F) polymers of globular G-actin subunits. Actin filaments are organized into bundles and networks, and are attached to the cell membrane, by diverse cross-linking proteins. During cell migration, actin filament bundles form either radially at the leading edge or as axial stress fibers. Early studies demonstrated that loss-of-function mutations in ciliopathy genes increased stress fiber formation and impaired ciliogenesis whereas pharmacological inhibition of actin polymerization promoted ciliogenesis. These studies suggest that polymerization of the actin cytoskeleton, F-actin branching and the formation of stress fibers all inhibit primary cilium formation, whereas depolymerization or depletion of actin enhance ciliogenesis. Here, we review the mechanistic basis for these effects on ciliogenesis, which comprise several cellular processes acting in concert at different timescales. Actin polymerization is both a physical barrier to both cilia-targeted vesicle transport and to the membrane remodeling required for ciliogenesis. In contrast, actin may cause cilia loss by localizing disassembly factors at the ciliary base, and F-actin branching may itself activate the YAP/TAZ pathway to promote cilia disassembly. The fundamental role of actin polymerization in the control of ciliogenesis may present potential new targets for disease-modifying therapeutic approaches in treating ciliopathies.
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Affiliation(s)
| | | | - Colin A. Johnson
- Leeds Institute of Medical Research at St. James’s, University of Leeds, Leeds, United Kingdom
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19
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de Beer MA, Giepmans BNG. Nanobody-Based Probes for Subcellular Protein Identification and Visualization. Front Cell Neurosci 2020; 14:573278. [PMID: 33240044 PMCID: PMC7667270 DOI: 10.3389/fncel.2020.573278] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Accepted: 10/05/2020] [Indexed: 12/14/2022] Open
Abstract
Understanding how building blocks of life contribute to physiology is greatly aided by protein identification and cellular localization. The two main labeling approaches developed over the past decades are labeling with antibodies such as immunoglobulin G (IgGs) or use of genetically encoded tags such as fluorescent proteins. However, IgGs are large proteins (150 kDa), which limits penetration depth and uncertainty of target position caused by up to ∼25 nm distance of the label created by the chosen targeting approach. Additionally, IgGs cannot be easily recombinantly modulated and engineered as part of fusion proteins because they consist of multiple independent translated chains. In the last decade single domain antigen binding proteins are being explored in bioscience as a tool in revealing molecular identity and localization to overcome limitations by IgGs. These nanobodies have several potential benefits over routine applications. Because of their small size (15 kDa), nanobodies better penetrate during labeling procedures and improve resolution. Moreover, nanobodies cDNA can easily be fused with other cDNA. Multidomain proteins can thus be easily engineered consisting of domains for targeting (nanobodies) and visualization by fluorescence microscopy (fluorescent proteins) or electron microscopy (based on certain enzymes). Additional modules for e.g., purification are also easily added. These nanobody-based probes can be applied in cells for live-cell endogenous protein detection or may be purified prior to use on molecules, cells or tissues. Here, we present the current state of nanobody-based probes and their implementation in microscopy, including pitfalls and potential future opportunities.
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Affiliation(s)
- Marit A de Beer
- Department of Biomedical Sciences of Cells and Systems, University of Groningen, University Medical Center Groningen, Groningen, Netherlands
| | - Ben N G Giepmans
- Department of Biomedical Sciences of Cells and Systems, University of Groningen, University Medical Center Groningen, Groningen, Netherlands
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20
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Schiavon CR, Zhang T, Zhao B, Moore AS, Wales P, Andrade LR, Wu M, Sung TC, Dayn Y, Feng JW, Quintero OA, Shadel GS, Grosse R, Manor U. Actin chromobody imaging reveals sub-organellar actin dynamics. Nat Methods 2020; 17:917-921. [PMID: 32778832 PMCID: PMC7746311 DOI: 10.1038/s41592-020-0926-5] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Accepted: 07/15/2020] [Indexed: 12/31/2022]
Abstract
The actin cytoskeleton plays multiple critical roles in cells, from cell migration to organelle dynamics. The small and transient actin structures regulating organelle dynamics are challenging to detect with fluorescence microscopy, making it difficult to determine whether actin filaments are directly associated with specific membranes. To address these limitations, we developed fluorescent-protein-tagged actin nanobodies, termed 'actin chromobodies' (ACs), targeted to organelle membranes to enable high-resolution imaging of sub-organellar actin dynamics.
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Affiliation(s)
- Cara R Schiavon
- Waitt Advanced Biophotonics Center, Salk Institute for Biological Studies, La Jolla, CA, USA
- Molecular and Cellular Biology Laboratory, Salk Institute for Biological Studies, La Jolla, CA, USA
| | - Tong Zhang
- Waitt Advanced Biophotonics Center, Salk Institute for Biological Studies, La Jolla, CA, USA
| | - Bing Zhao
- Institute of Experimental and Clinical Pharmacology and Toxicology, University of Freiburg, Freiburg im Breisgau, Germany
| | - Andrew S Moore
- Janelia Research Campus, Howard Hughes Medical Institute, Chevy Chase, MD, USA
| | - Pauline Wales
- Waitt Advanced Biophotonics Center, Salk Institute for Biological Studies, La Jolla, CA, USA
- Molecular and Cellular Biology Laboratory, Salk Institute for Biological Studies, La Jolla, CA, USA
| | - Leonardo R Andrade
- Waitt Advanced Biophotonics Center, Salk Institute for Biological Studies, La Jolla, CA, USA
| | - Melissa Wu
- Waitt Advanced Biophotonics Center, Salk Institute for Biological Studies, La Jolla, CA, USA
| | - Tsung-Chang Sung
- Transgenic Core, Salk Institute for Biological Studies, La Jolla, CA, USA
| | - Yelena Dayn
- Transgenic Core, Salk Institute for Biological Studies, La Jolla, CA, USA
| | - Jasmine W Feng
- Department of Biology, University of Richmond, Richmond, VA, USA
| | - Omar A Quintero
- Department of Biology, University of Richmond, Richmond, VA, USA
| | - Gerald S Shadel
- Molecular and Cellular Biology Laboratory, Salk Institute for Biological Studies, La Jolla, CA, USA
| | - Robert Grosse
- Institute of Experimental and Clinical Pharmacology and Toxicology, University of Freiburg, Freiburg im Breisgau, Germany
| | - Uri Manor
- Waitt Advanced Biophotonics Center, Salk Institute for Biological Studies, La Jolla, CA, USA.
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21
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Eggenstein E, Richter A, Skerra A. FluoroCalins: engineered lipocalins with novel binding functions fused to a fluorescent protein for applications in biomolecular imaging and detection. Protein Eng Des Sel 2019; 32:289-296. [PMID: 31927584 DOI: 10.1093/protein/gzz047] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Accepted: 12/03/2019] [Indexed: 11/14/2022] Open
Abstract
FluoroCalins represent novel bifunctional protein reagents derived from engineered lipocalins fused to a fluorescent reporter protein, here the enhanced green fluorescent protein (eGFP). We demonstrate the construction, facile bacterial production and broad applicability of FluoroCalins using two Anticalin® molecules directed against the tumor vasculature-associated extra domain B of fibronectin (ED-B) and the vascular endothelial growth factor receptor 3, a marker of tumor and lymphangiogenesis. FluoroCalins were prepared with two different spacers: (i) a short Ser3Ala linker and (ii) a long hydrophilic and conformationally unstructured PASylation® polypeptide comprising 200 Pro, Ala and Ser residues. These FluoroCalins were applied for direct target quantification in enzyme-linked immunosorbent assay as well as target detection by flow cytometry and fluorescence microscopy of live and fixed cells, respectively, demonstrating high specificity and signal-to-noise ratio. Hence, FluoroCalins offer a promising alternative to antibody-based reagents for state of the art fluorescent in vitro detection and biomolecular imaging.
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Affiliation(s)
- Evelyn Eggenstein
- Lehrstuhl für Biologische Chemie, Technische Universität München, Emil-Erlenmeyer-Forum 5, 85354 Freising, Germany
| | - Antonia Richter
- Lehrstuhl für Biologische Chemie, Technische Universität München, Emil-Erlenmeyer-Forum 5, 85354 Freising, Germany
| | - Arne Skerra
- Lehrstuhl für Biologische Chemie, Technische Universität München, Emil-Erlenmeyer-Forum 5, 85354 Freising, Germany
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22
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Reshetniak S, Rizzoli SO. Interrogating Synaptic Architecture: Approaches for Labeling Organelles and Cytoskeleton Components. Front Synaptic Neurosci 2019; 11:23. [PMID: 31507402 PMCID: PMC6716447 DOI: 10.3389/fnsyn.2019.00023] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Accepted: 08/02/2019] [Indexed: 01/06/2023] Open
Abstract
Synaptic transmission has been studied for decades, as a fundamental step in brain function. The structure of the synapse, and its changes during activity, turned out to be key aspects not only in the transfer of information between neurons, but also in cognitive processes such as learning and memory. The overall synaptic morphology has traditionally been studied by electron microscopy, which enables the visualization of synaptic structure in great detail. The changes in the organization of easily identified structures, such as the presynaptic active zone, or the postsynaptic density, are optimally studied via electron microscopy. However, few reliable methods are available for labeling individual organelles or protein complexes in electron microscopy. For such targets one typically relies either on combination of electron and fluorescence microscopy, or on super-resolution fluorescence microscopy. This review focuses on approaches and techniques used to specifically reveal synaptic organelles and protein complexes, such as cytoskeletal assemblies. We place the strongest emphasis on methods detecting the targets of interest by affinity binding, and we discuss the advantages and limitations of each method.
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Affiliation(s)
- Sofiia Reshetniak
- Institute for Neuro- and Sensory Physiology, Center for Biostructural Imaging of Neurodegeneration (BIN), University Medical Center Göttingen, Göttingen, Germany
- International Max Planck Research School for Molecular Biology, Göttingen, Germany
| | - Silvio O. Rizzoli
- Institute for Neuro- and Sensory Physiology, Center for Biostructural Imaging of Neurodegeneration (BIN), University Medical Center Göttingen, Göttingen, Germany
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Stortz JF, Del Rosario M, Singer M, Wilkes JM, Meissner M, Das S. Formin-2 drives polymerisation of actin filaments enabling segregation of apicoplasts and cytokinesis in Plasmodium falciparum. eLife 2019; 8:e49030. [PMID: 31322501 PMCID: PMC6688858 DOI: 10.7554/elife.49030] [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: 06/05/2019] [Accepted: 07/17/2019] [Indexed: 12/16/2022] Open
Abstract
In addition to its role in erythrocyte invasion, Plasmodium falciparum actin is implicated in endocytosis, cytokinesis and inheritance of the chloroplast-like organelle called the apicoplast. Previously, the inability to visualise filamentous actin (F-actin) dynamics had restricted the characterisation of both F-actin and actin regulatory proteins, a limitation we recently overcame for Toxoplasma (Periz et al, 2017). Here, we have expressed and validated actin-binding chromobodies as F-actin-sensors in Plasmodium falciparum and characterised in-vivo actin dynamics. F-actin could be chemically modulated, and genetically disrupted upon conditionally deleting actin-1. In a comparative approach, we demonstrate that Formin-2, a predicted nucleator of F-actin, is responsible for apicoplast inheritance in both Plasmodium and Toxoplasma, and additionally mediates efficient cytokinesis in Plasmodium. Finally, time-averaged local intensity measurements of F-actin in Toxoplasma conditional mutants revealed molecular determinants of spatiotemporally regulated F-actin flow. Together, our data indicate that Formin-2 is the primary F-actin nucleator during apicomplexan intracellular growth, mediating multiple essential functions.
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Affiliation(s)
- Johannes Felix Stortz
- Wellcome Centre for Integrative Parasitology, Institute of Infection, Immunity & InflammationUniversity of GlasgowGlasgowUnited Kingdom
| | - Mario Del Rosario
- Wellcome Centre for Integrative Parasitology, Institute of Infection, Immunity & InflammationUniversity of GlasgowGlasgowUnited Kingdom
| | - Mirko Singer
- Faculty of Veterinary Medicine, Experimental ParasitologyLudwig Maximilian UniversityMunichGermany
| | - Jonathan M Wilkes
- Wellcome Centre for Integrative Parasitology, Institute of Infection, Immunity & InflammationUniversity of GlasgowGlasgowUnited Kingdom
| | - Markus Meissner
- Wellcome Centre for Integrative Parasitology, Institute of Infection, Immunity & InflammationUniversity of GlasgowGlasgowUnited Kingdom
- Faculty of Veterinary Medicine, Experimental ParasitologyLudwig Maximilian UniversityMunichGermany
| | - Sujaan Das
- Wellcome Centre for Integrative Parasitology, Institute of Infection, Immunity & InflammationUniversity of GlasgowGlasgowUnited Kingdom
- Faculty of Veterinary Medicine, Experimental ParasitologyLudwig Maximilian UniversityMunichGermany
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Abdellatif MEA, Hipp L, Plessner M, Walther P, Knöll B. Indirect visualization of endogenous nuclear actin by correlative light and electron microscopy (CLEM) using an actin-directed chromobody. Histochem Cell Biol 2019; 152:133-143. [PMID: 31154480 PMCID: PMC6675784 DOI: 10.1007/s00418-019-01795-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/15/2019] [Indexed: 12/14/2022]
Abstract
Actin fulfills important cytoplasmic but also nuclear functions in eukaryotic cells. In the nucleus, actin modulates gene expression and chromatin remodeling. Monomeric (G-actin) and polymerized actin (F-actin) have been analyzed by fluorescence microscopy in the nucleus; however, the resolution at the ultrastructural level has not been investigated in great detail. We provide a first documentation of nuclear actin in mouse fibroblasts by electron microscopy (EM). For this, we employed correlative light and electron microscopy on the same section using actin-directed nanobodies recognizing endogenous monomeric and polymeric actin proteins (so-called nuclear Actin-chromobody-GFP; nAC-GFP). Indeed, using this strategy, we could identify actin proteins present in the nucleus. Here, immunogold-labeled actin proteins were spread throughout the entire nucleoplasm. Of note, nuclear actin was complementarily localized to DAPI-positive areas, the latter marking preferentially transcriptionally inactive heterochromatin. Since actin aggregates in rod structures upon cell stress including neurodegeneration, we analyzed nuclear actin at the ultrastructural level after DMSO or UV-mediated cell damage. In those cells the ratio between cytoplasmic and nuclear gold-labeled actin proteins was altered compared to untreated control cells. In summary, this EM analysis (i) confirmed the presence of endogenous nuclear actin at ultrastructural resolution, (ii) revealed the actin abundance in less chromatin-dense regions potentially reflecting more transcriptionally active euchromatin rather than transcriptionally inactive heterochromatin and (iii) showed an altered abundance of actin-associated gold particles upon cell stress.
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Affiliation(s)
- Mohamed E A Abdellatif
- Central Facility for Electron Microscopy, Ulm University, Albert-Einstein-Allee 11, 89081, Ulm, Germany
| | - Lisa Hipp
- Institute of Physiological Chemistry, Ulm University, Albert-Einstein-Allee 11, 89081, Ulm, Germany
| | - Matthias Plessner
- Institute of Experimental and Clinical Pharmacology and Toxicology, University of Freiburg, Albertstr. 25, 79104, Freiburg, Germany
| | - Paul Walther
- Central Facility for Electron Microscopy, Ulm University, Albert-Einstein-Allee 11, 89081, Ulm, Germany
| | - Bernd Knöll
- Institute of Physiological Chemistry, Ulm University, Albert-Einstein-Allee 11, 89081, Ulm, Germany.
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25
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Aguilar G, Matsuda S, Vigano MA, Affolter M. Using Nanobodies to Study Protein Function in Developing Organisms. Antibodies (Basel) 2019; 8:E16. [PMID: 31544822 PMCID: PMC6640693 DOI: 10.3390/antib8010016] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Revised: 01/30/2019] [Accepted: 02/01/2019] [Indexed: 12/28/2022] Open
Abstract
Polyclonal and monoclonal antibodies have been invaluable tools to study proteins over the past decades. While indispensable for most biological studies including developmental biology, antibodies have been used mostly in fixed tissues or as binding reagents in the extracellular milieu. For functional studies and for clinical applications, antibodies have been functionalized by covalently fusing them to heterologous partners (i.e., chemicals, proteins or other moieties). Such functionalized antibodies have been less widely used in developmental biology studies. In the past few years, the discovery and application of small functional binding fragments derived from single-chain antibodies, so-called nanobodies, has resulted in novel approaches to study proteins during the development of multicellular animals in vivo. Expression of functionalized nanobody fusions from integrated transgenes allows manipulating proteins of interest in the extracellular and the intracellular milieu in a tissue- and time-dependent manner in an unprecedented manner. Here, we describe how nanobodies have been used in the field of developmental biology and look into the future to imagine how else nanobody-based reagents could be further developed to study the proteome in living organisms.
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Affiliation(s)
- Gustavo Aguilar
- Biozentrum, University of Basel, Klingelbergstrasse 70, 4056 Basel, Switzerland.
| | - Shinya Matsuda
- Biozentrum, University of Basel, Klingelbergstrasse 70, 4056 Basel, Switzerland.
| | - M Alessandra Vigano
- Biozentrum, University of Basel, Klingelbergstrasse 70, 4056 Basel, Switzerland.
| | - Markus Affolter
- Biozentrum, University of Basel, Klingelbergstrasse 70, 4056 Basel, Switzerland.
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26
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Vavrdová T, Šamajová O, Křenek P, Ovečka M, Floková P, Šnaurová R, Šamaj J, Komis G. Multicolour three dimensional structured illumination microscopy of immunolabeled plant microtubules and associated proteins. PLANT METHODS 2019; 15:22. [PMID: 30899319 PMCID: PMC6408805 DOI: 10.1186/s13007-019-0406-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Accepted: 02/26/2019] [Indexed: 05/04/2023]
Abstract
BACKGROUND In the present work, we provide an account of structured illumination microscopy (SIM) imaging of fixed and immunolabeled plant probes. We take advantage of SIM, to superresolve intracellular structures at a considerable z-range and circumvent its low temporal resolution capacity during the study of living samples. Further, we validate the protocol for the imaging of fixed transgenic material expressing fluorescent protein-based markers of different subcellular structures. RESULTS Focus is given on 3D imaging of bulky subcellular structures, such as mitotic and cytokinetic microtubule arrays as well as on the performance of SIM using multichannel imaging and the quantitative correlations that can be deduced. As a proof of concept, we provide a superresolution output on the organization of cortical microtubules in wild-type and mutant Arabidopsis cells, including aberrant preprophase microtubule bands and phragmoplasts in a cytoskeletal mutant devoid of the p60 subunit of the microtubule severing protein KATANIN and refined details of cytoskeletal aberrations in the mitogen activated protein kinase (MAPK) mutant mpk4. We further demonstrate, in a qualitative and quantitative manner, colocalizations between MPK6 and unknown dually phosphorylated and activated MAPK species and we follow the localization of the microtubule associated protein 65-3 (MAP65-3) in telophase and cytokinetic microtubular arrays. CONCLUSIONS 3D SIM is a powerful, versatile and adaptable microscopy method for elucidating spatial relationships between subcellular compartments. Improved methods of sample preparation aiming to the compensation of refractive index mismatches, allow the use of 3D SIM in the documentation of complex plant cell structures, such as microtubule arrays and the elucidation of their interactions with microtubule associated proteins.
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Affiliation(s)
- T. Vavrdová
- Department of Cell Biology, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University Olomouc, Olomouc, Czech Republic
| | - O. Šamajová
- Department of Cell Biology, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University Olomouc, Olomouc, Czech Republic
| | - P. Křenek
- Department of Cell Biology, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University Olomouc, Olomouc, Czech Republic
| | - M. Ovečka
- Department of Cell Biology, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University Olomouc, Olomouc, Czech Republic
| | - P. Floková
- Department of Cell Biology, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University Olomouc, Olomouc, Czech Republic
| | - R. Šnaurová
- Department of Cell Biology, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University Olomouc, Olomouc, Czech Republic
| | - J. Šamaj
- Department of Cell Biology, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University Olomouc, Olomouc, Czech Republic
| | - G. Komis
- Department of Cell Biology, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University Olomouc, Olomouc, Czech Republic
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27
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Greenwald EC, Mehta S, Zhang J. Genetically Encoded Fluorescent Biosensors Illuminate the Spatiotemporal Regulation of Signaling Networks. Chem Rev 2018; 118:11707-11794. [PMID: 30550275 PMCID: PMC7462118 DOI: 10.1021/acs.chemrev.8b00333] [Citation(s) in RCA: 302] [Impact Index Per Article: 50.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Cellular signaling networks are the foundation which determines the fate and function of cells as they respond to various cues and stimuli. The discovery of fluorescent proteins over 25 years ago enabled the development of a diverse array of genetically encodable fluorescent biosensors that are capable of measuring the spatiotemporal dynamics of signal transduction pathways in live cells. In an effort to encapsulate the breadth over which fluorescent biosensors have expanded, we endeavored to assemble a comprehensive list of published engineered biosensors, and we discuss many of the molecular designs utilized in their development. Then, we review how the high temporal and spatial resolution afforded by fluorescent biosensors has aided our understanding of the spatiotemporal regulation of signaling networks at the cellular and subcellular level. Finally, we highlight some emerging areas of research in both biosensor design and applications that are on the forefront of biosensor development.
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Affiliation(s)
- Eric C Greenwald
- University of California , San Diego, 9500 Gilman Drive, BRFII , La Jolla , CA 92093-0702 , United States
| | - Sohum Mehta
- University of California , San Diego, 9500 Gilman Drive, BRFII , La Jolla , CA 92093-0702 , United States
| | - Jin Zhang
- University of California , San Diego, 9500 Gilman Drive, BRFII , La Jolla , CA 92093-0702 , United States
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28
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Arabidopsis vegetative actin isoforms, AtACT2 and AtACT7, generate distinct filament arrays in living plant cells. Sci Rep 2018. [PMID: 29531328 PMCID: PMC5847576 DOI: 10.1038/s41598-018-22707-w] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Flowering plants express multiple actin isoforms. Previous studies suggest that individual actin isoforms have specific functions; however, the subcellular localization of actin isoforms in plant cells remains obscure. Here, we transiently expressed and observed major Arabidopsis vegetative actin isoforms, AtACT2 and AtACT7, as fluorescent-fusion proteins. By optimizing the linker sequence between fluorescent protein and actin, we succeeded in observing filaments that contained these expressed actin isoforms fused with green fluorescent protein (GFP) in Arabidopsis protoplasts. Different colored fluorescent proteins fused with AtACT2 and AtACT7 and co-expressed in Nicotiana benthamiana mesophyll cells co-polymerized in a segregated manner along filaments. In epidermal cells, surprisingly, AtACT2 and AtACT7 tended to polymerize into different types of filaments. AtACT2 was incorporated into thinner filaments, whereas AtACT7 was incorporated into thick bundles. We conclude that different actin isoforms are capable of constructing unique filament arrays, depending on the cell type or tissue. Interestingly, staining patterns induced by two indirect actin filament probes, Lifeact and mTalin1, were different between filaments containing AtACT2 and those containing AtACT7. We suggest that filaments containing different actin isoforms bind specific actin-binding proteins in vivo, since the two probes comprise actin-binding domains from different actin-binding proteins.
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29
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Zhong W, Li G, Yu X, Zhu M, Gong L, Wan Y. Sensitive detection of Bacillus thuringiensis Cry1B toxin based on camel single-domain antibodies. Microbiologyopen 2018; 7:e00581. [PMID: 29476614 PMCID: PMC6079177 DOI: 10.1002/mbo3.581] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Revised: 10/08/2017] [Accepted: 10/24/2017] [Indexed: 12/18/2022] Open
Abstract
Bt Cry1B toxin, a residue in insect-resistant transgenic plants, has been identified to be harmful to human health. Therefore, it is urgent to detect the Cry1B toxin level in each kind of transgenic plant. Nbs, with prominently unique physiochemical properties, are becoming more and more promising tools in the detection of target antigens. In this study, an immune phage display library that was of high quality was successfully constructed for the screening of Cry1B-specific Nbs with excellent specificity, affinity, and thermostable. Subsequently, a novel sandwich ELISA for Cry1B detection was established, which was based on the biotin-streptavidin system using these aforementioned Nbs. This established detection system presented a linear working range from 5 to 1000 ng ml-1 and a low detection limit of 3.46 ng ml-1 . The recoveries from spiked samples were in the range of 82.51%-113.56% with a relative standard deviation (RSD) lower than 5.00%. Taken together, the proposed sandwich ELISA would be a potential method for the detection of Cry1B toxin in transgenic Bt plants specifically and sensitively.
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Affiliation(s)
- Wenjing Zhong
- CAS Key Laboratory of Receptor Research, Shanghai Institute of Material Medical, Chinese Academy of Sciences, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Guanghui Li
- CAS Key Laboratory of Receptor Research, Shanghai Institute of Material Medical, Chinese Academy of Sciences, Shanghai, China
| | - Xiaolu Yu
- CAS Key Laboratory of Receptor Research, Shanghai Institute of Material Medical, Chinese Academy of Sciences, Shanghai, China
| | - Min Zhu
- CAS Key Laboratory of Receptor Research, Shanghai Institute of Material Medical, Chinese Academy of Sciences, Shanghai, China
| | - Likun Gong
- CAS Key Laboratory of Receptor Research, Shanghai Institute of Material Medical, Chinese Academy of Sciences, Shanghai, China
| | - Yakun Wan
- CAS Key Laboratory of Receptor Research, Shanghai Institute of Material Medical, Chinese Academy of Sciences, Shanghai, China
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30
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Paez-Garcia A, Sparks JA, de Bang L, Blancaflor EB. Plant Actin Cytoskeleton: New Functions from Old Scaffold. PLANT CELL MONOGRAPHS 2018. [DOI: 10.1007/978-3-319-69944-8_6] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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31
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Wang P, Hawkins TJ, Hussey PJ. Connecting membranes to the actin cytoskeleton. CURRENT OPINION IN PLANT BIOLOGY 2017; 40:71-76. [PMID: 28779654 DOI: 10.1016/j.pbi.2017.07.008] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Accepted: 07/13/2017] [Indexed: 05/10/2023]
Abstract
In plants, the actin cytoskeleton plays a major role in organelle movement, cargo transport, maintaining cell polarity and controlling the morphogenesis of endomembrane systems. All of these events require a direct connection between membrane structures and the cytoskeleton. Our knowledge in this field has been greatly advanced by a few recent discoveries including the identification of the plant specific NETWORKED family of proteins, which can mediate such linkages. Other proteins that are known to regulate actin nucleation and polymerization are also likely to be involved, but many key questions still remain unanswered. In this paper, we will focus on recent research on the interfaces between the actin cytoskeleton and membranes of the endoplasmic reticulum, the vacuole and autophagosomes.
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Affiliation(s)
- Pengwei Wang
- Department of Biosciences, Durham University, South Road, Durham DH1 3LE, UK; Key Laboratory of Horticultural Plant Biology (Ministry of Education), College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan 430070, Hubei Province, PR China
| | - Tim J Hawkins
- Department of Biosciences, Durham University, South Road, Durham DH1 3LE, UK
| | - Patrick J Hussey
- Department of Biosciences, Durham University, South Road, Durham DH1 3LE, UK.
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32
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Traenkle B, Rothbauer U. Under the Microscope: Single-Domain Antibodies for Live-Cell Imaging and Super-Resolution Microscopy. Front Immunol 2017; 8:1030. [PMID: 28883823 PMCID: PMC5573807 DOI: 10.3389/fimmu.2017.01030] [Citation(s) in RCA: 72] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Accepted: 08/09/2017] [Indexed: 12/12/2022] Open
Abstract
Single-domain antibodies (sdAbs) have substantially expanded the possibilities of advanced cellular imaging such as live-cell or super-resolution microscopy to visualize cellular antigens and their dynamics. In addition to their unique properties including small size, high stability, and solubility in many environments, sdAbs can be efficiently functionalized according to the needs of the respective imaging approach. Genetically encoded intrabodies fused to fluorescent proteins (chromobodies) have become versatile tools to study dynamics of endogenous proteins in living cells. Additionally, sdAbs conjugated to organic dyes were shown to label cellular structures with high density and minimal fluorophore displacement making them highly attractive probes for super-resolution microscopy. Here, we review recent advances of the chromobody technology to visualize localization and dynamics of cellular targets and the application of chromobody-based cell models for compound screening. Acknowledging the emerging importance of super-resolution microscopy in cell biology, we further discuss advantages and challenges of sdAbs for this technology.
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Affiliation(s)
- Bjoern Traenkle
- Pharmaceutical Biotechnology, Eberhard Karls University Tuebingen, Tuebingen, Germany
| | - Ulrich Rothbauer
- Pharmaceutical Biotechnology, Eberhard Karls University Tuebingen, Tuebingen, Germany.,Natural and Medical Sciences Institute at the University of Tuebingen, Reutlingen, Germany
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33
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Periz J, Whitelaw J, Harding C, Gras S, Del Rosario Minina MI, Latorre-Barragan F, Lemgruber L, Reimer MA, Insall R, Heaslip A, Meissner M. Toxoplasma gondii F-actin forms an extensive filamentous network required for material exchange and parasite maturation. eLife 2017; 6:e24119. [PMID: 28322189 PMCID: PMC5375643 DOI: 10.7554/elife.24119] [Citation(s) in RCA: 76] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Accepted: 03/09/2017] [Indexed: 01/14/2023] Open
Abstract
Apicomplexan actin is important during the parasite's life cycle. Its polymerization kinetics are unusual, permitting only short, unstable F-actin filaments. It has not been possible to study actin in vivo and so its physiological roles have remained obscure, leading to models distinct from conventional actin behaviour. Here a modified version of the commercially available actin-chromobody was tested as a novel tool for visualising F-actin dynamics in Toxoplasma gondii. Cb labels filamentous actin structures within the parasite cytosol and labels an extensive F-actin network that connects parasites within the parasitophorous vacuole and allows vesicles to be exchanged between parasites. In the absence of actin, parasites lack a residual body and inter-parasite connections and grow in an asynchronous and disorganized manner. Collectively, these data identify new roles for actin in the intracellular phase of the parasites lytic cycle and provide a robust new tool for imaging parasitic F-actin dynamics.
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Affiliation(s)
- Javier Periz
- Wellcome Centre for Molecular Parasitology, Institute of Infection, Immunity & Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Jamie Whitelaw
- Wellcome Centre for Molecular Parasitology, Institute of Infection, Immunity & Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Clare Harding
- Wellcome Centre for Molecular Parasitology, Institute of Infection, Immunity & Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Simon Gras
- Wellcome Centre for Molecular Parasitology, Institute of Infection, Immunity & Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Mario Igor Del Rosario Minina
- Wellcome Centre for Molecular Parasitology, Institute of Infection, Immunity & Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Fernanda Latorre-Barragan
- Wellcome Centre for Molecular Parasitology, Institute of Infection, Immunity & Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Leandro Lemgruber
- Wellcome Centre for Molecular Parasitology, Institute of Infection, Immunity & Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Madita Alice Reimer
- Wellcome Centre for Molecular Parasitology, Institute of Infection, Immunity & Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Robert Insall
- Cancer Research United Kingdom Beatson Institute, Bearsden, United Kingdom
| | - Aoife Heaslip
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, United States
| | - Markus Meissner
- Wellcome Centre for Molecular Parasitology, Institute of Infection, Immunity & Inflammation, University of Glasgow, Glasgow, United Kingdom
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34
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Wang P, Hussey PJ. NETWORKED 3B: a novel protein in the actin cytoskeleton-endoplasmic reticulum interaction. JOURNAL OF EXPERIMENTAL BOTANY 2017; 68:1441-1450. [PMID: 28369569 PMCID: PMC5441911 DOI: 10.1093/jxb/erx047] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
In plants movement of the endoplasmic reticulum (ER) is dependent on the actin cytoskeleton. However little is known about proteins that link the ER membrane and the actin cytoskeleton. Here we identified a novel protein, NETWORKED 3B (NET3B), which is associated with the ER and actin cytoskeleton in vivo. NET3B belongs to a superfamily of plant specific actin binding proteins, the NETWORKED family. NET3B associates with the actin cytoskeleton in vivo through an N-terminal NET actin binding (NAB) domain, which has been well-characterized in other members of the NET family. A three amino acid insertion, Val-Glu-Asp, in the NAB domain of NET3B appears to lower its ability to localize to the actin cytoskeleton compared with NET1A, the founding member of the NET family. The C-terminal domain of NET3B links the protein to the ER. Overexpression of NET3B enhanced the association between the ER and the actin cytoskeleton, and the extent of this association was dependent on the amount of NET3B available. Another effect of NET3B overexpression was a reduction in ER membrane diffusion. In conclusion, our results revealed that NET3B modulates ER and actin cytoskeleton interactions in higher plants.
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Affiliation(s)
- Pengwei Wang
- Department of Biosciences, Durham University, South road, Durham, DH1 3LE, UK
- College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan 430070, Hubei Province, PR China
| | - Patrick J Hussey
- Department of Biosciences, Durham University, South road, Durham, DH1 3LE,UK
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35
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Abstract
Actin functions in a multitude of cellular processes owing to its ability to polymerize into filaments, which can be further organized into higher-order structures by an array of actin-binding and regulatory proteins. Therefore, research on actin and actin-related functions relies on the visualization of actin structures without interfering with the cycles of actin polymerization and depolymerization that underlie cellular actin dynamics. In this Cell Science at a Glance and the accompanying poster, we briefly evaluate the different techniques and approaches currently applied to analyze and visualize cellular actin structures, including in the nuclear compartment. Referring to the gold standard F-actin marker phalloidin to stain actin in fixed samples and tissues, we highlight methods for visualization of actin in living cells, which mostly apply the principle of genetically fusing fluorescent proteins to different actin-binding domains, such as LifeAct, utrophin and F-tractin, as well as anti-actin-nanobody technology. In addition, the compound SiR-actin and the expression of GFP-actin are also applicable for various types of live-cell analyses. Overall, the visualization of actin within a physiological context requires a careful choice of method, as well as a tight control of the amount or the expression level of a given detection probe in order to minimize its influence on endogenous actin dynamics.
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Affiliation(s)
- Michael Melak
- Institute of Pharmacology, Biochemical-Pharmacological Center (BPC), University of Marburg, Karl-von-Frisch-Straße 1, Marburg 35043, Germany
| | - Matthias Plessner
- Institute of Pharmacology, Biochemical-Pharmacological Center (BPC), University of Marburg, Karl-von-Frisch-Straße 1, Marburg 35043, Germany
| | - Robert Grosse
- Institute of Pharmacology, Biochemical-Pharmacological Center (BPC), University of Marburg, Karl-von-Frisch-Straße 1, Marburg 35043, Germany
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36
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Li T, Vandesquille M, Koukouli F, Dudeffant C, Youssef I, Lenormand P, Ganneau C, Maskos U, Czech C, Grueninger F, Duyckaerts C, Dhenain M, Bay S, Delatour B, Lafaye P. Camelid single-domain antibodies: A versatile tool for in vivo imaging of extracellular and intracellular brain targets. J Control Release 2016; 243:1-10. [PMID: 27671875 DOI: 10.1016/j.jconrel.2016.09.019] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2016] [Revised: 09/09/2016] [Accepted: 09/20/2016] [Indexed: 01/01/2023]
Abstract
Detection of intracerebral targets with imaging probes is challenging due to the non-permissive nature of blood-brain barrier (BBB). The present work describes two novel single-domain antibodies (VHHs or nanobodies) that specifically recognize extracellular amyloid deposits and intracellular tau neurofibrillary tangles, the two core lesions of Alzheimer's disease (AD). Following intravenous administration in transgenic mouse models of AD, in vivo real-time two-photon microscopy showed gradual extravasation of the VHHs across the BBB, diffusion in the parenchyma and labeling of amyloid deposits and neurofibrillary tangles. Our results demonstrate that VHHs can be used as specific BBB-permeable probes for both extracellular and intracellular brain targets and suggest new avenues for therapeutic and diagnostic applications in neurology.
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Affiliation(s)
- Tengfei Li
- Institut Pasteur, CITECH, Plateforme d'Ingénierie des Anticorps, 75724 Paris Cedex 15, France; Sorbonne Universités, UPMC Univ. Paris 06 UMR S 1127, F-75013 Paris, France; Inserm U 1127, Paris, France; CNRS UMR 7225, Paris, France; ICM, Paris, France; Université Paris Descartes, Paris 5, France
| | - Matthias Vandesquille
- Institut Pasteur, Unité de Chimie des Biomolécules, 75724 Paris Cedex 15, France; CNRS UMR 3523, 75724 Paris Cedex 15, France; Commissariat à l'Energie Atomique et aux Energies Alternatives (CEA), Direction de la Recherche Fondamentale (DRF), Institut d'Imagerie Biomédicale (I2BM), MIRCen, F-92260 Fontenay-aux-Roses, France; Centre National de la Recherche Scientifique (CNRS), Université Paris-Sud, Université Paris-Saclay UMR 9199, Neurodegenerative Diseases Laboratory, F-92260 Fontenay-aux-Roses, France
| | - Fani Koukouli
- Institut Pasteur, Neurobiologie intégrative des systèmes cholinergiques, CNRS UMR 3571, Paris, France
| | - Clémence Dudeffant
- Sorbonne Universités, UPMC Univ. Paris 06 UMR S 1127, F-75013 Paris, France; Inserm U 1127, Paris, France; CNRS UMR 7225, Paris, France; ICM, Paris, France; Commissariat à l'Energie Atomique et aux Energies Alternatives (CEA), Direction de la Recherche Fondamentale (DRF), Institut d'Imagerie Biomédicale (I2BM), MIRCen, F-92260 Fontenay-aux-Roses, France; Centre National de la Recherche Scientifique (CNRS), Université Paris-Sud, Université Paris-Saclay UMR 9199, Neurodegenerative Diseases Laboratory, F-92260 Fontenay-aux-Roses, France
| | - Ihsen Youssef
- Sorbonne Universités, UPMC Univ. Paris 06 UMR S 1127, F-75013 Paris, France; Inserm U 1127, Paris, France; CNRS UMR 7225, Paris, France; ICM, Paris, France
| | - Pascal Lenormand
- Institut Pasteur, CITECH, Plateforme d'Ingénierie des Anticorps, 75724 Paris Cedex 15, France
| | - Christelle Ganneau
- Institut Pasteur, Unité de Chimie des Biomolécules, 75724 Paris Cedex 15, France; CNRS UMR 3523, 75724 Paris Cedex 15, France
| | - Uwe Maskos
- Institut Pasteur, Neurobiologie intégrative des systèmes cholinergiques, CNRS UMR 3571, Paris, France
| | - Christian Czech
- F. Hoffmann-La Roche AG, Pharmaceutical Research and Early Development, NORD DTA, Roche Innovation Center Basel, CH-4070 Basel, Switzerland
| | - Fiona Grueninger
- F. Hoffmann-La Roche AG, Pharmaceutical Research and Early Development, NORD DTA, Roche Innovation Center Basel, CH-4070 Basel, Switzerland
| | - Charles Duyckaerts
- Sorbonne Universités, UPMC Univ. Paris 06 UMR S 1127, F-75013 Paris, France; Inserm U 1127, Paris, France; CNRS UMR 7225, Paris, France; ICM, Paris, France
| | - Marc Dhenain
- Commissariat à l'Energie Atomique et aux Energies Alternatives (CEA), Direction de la Recherche Fondamentale (DRF), Institut d'Imagerie Biomédicale (I2BM), MIRCen, F-92260 Fontenay-aux-Roses, France; Centre National de la Recherche Scientifique (CNRS), Université Paris-Sud, Université Paris-Saclay UMR 9199, Neurodegenerative Diseases Laboratory, F-92260 Fontenay-aux-Roses, France
| | - Sylvie Bay
- Institut Pasteur, Unité de Chimie des Biomolécules, 75724 Paris Cedex 15, France; CNRS UMR 3523, 75724 Paris Cedex 15, France
| | - Benoît Delatour
- Sorbonne Universités, UPMC Univ. Paris 06 UMR S 1127, F-75013 Paris, France; Inserm U 1127, Paris, France; CNRS UMR 7225, Paris, France; ICM, Paris, France
| | - Pierre Lafaye
- Institut Pasteur, CITECH, Plateforme d'Ingénierie des Anticorps, 75724 Paris Cedex 15, France.
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Li T, Qi S, Unger M, Hou YN, Deng QW, Liu J, Lam CMC, Wang XW, Xin D, Zhang P, Koch-Nolte F, Hao Q, Zhang H, Lee HC, Zhao YJ. Immuno-targeting the multifunctional CD38 using nanobody. Sci Rep 2016; 6:27055. [PMID: 27251573 PMCID: PMC4890012 DOI: 10.1038/srep27055] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Accepted: 04/29/2016] [Indexed: 12/29/2022] Open
Abstract
CD38, as a cell surface antigen is highly expressed in several hematologic malignancies including multiple myeloma (MM) and has been proven to be a good target for immunotherapy of the disease. CD38 is also a signaling enzyme responsible for the metabolism of two novel calcium messenger molecules. To be able to target this multifunctional protein, we generated a series of nanobodies against CD38 with high affinities. Crystal structures of the complexes of CD38 with the nanobodies were solved, identifying three separate epitopes on the carboxyl domain. Chromobodies, engineered by tagging the nanobody with fluorescence proteins, provide fast, simple and versatile tools for quantifying CD38 expression. Results confirmed that CD38 was highly expressed in malignant MM cells compared with normal white blood cells. The immunotoxin constructed by splicing the nanobody with a bacterial toxin, PE38 shows highly selective cytotoxicity against patient-derived MM cells as well as the cell lines, with half maximal effective concentration reaching as low as 10−11 molar. The effectiveness of the immunotoxin can be further increased by stimulating CD38 expression using retinoid acid. These results set the stage for the development of clinical therapeutics as well as diagnostic screening for myeloma.
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Affiliation(s)
- Ting Li
- School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen 518055, China
| | - Shali Qi
- School of Biomedical Sciences, Li Ka Shing School of Medicine, The University of Hong Kong, Hong Kong, China
| | - Mandy Unger
- Institute of Immunology, University Medical Center Hamburg-Eppendorf, Martinistr. 52, 20246 Hamburg, Germany
| | - Yun Nan Hou
- School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen 518055, China
| | - Qi Wen Deng
- School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen 518055, China
| | - Jun Liu
- School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen 518055, China
| | - Connie M C Lam
- School of Biomedical Sciences, Li Ka Shing School of Medicine, The University of Hong Kong, Hong Kong, China
| | - Xian Wang Wang
- Functional Laboratory, School of Medicine, Yangtze University, 1 Nanhuan Road, Jingzhou, Hubei 434023, China
| | - Du Xin
- Department of Hematology, Shenzhen Second People's Hospital, The First Affiliated Hospital of Shenzhen University, Shenzhen 518029, China
| | - Peng Zhang
- Department of Oncology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Friedrich Koch-Nolte
- Institute of Immunology, University Medical Center Hamburg-Eppendorf, Martinistr. 52, 20246 Hamburg, Germany
| | - Quan Hao
- School of Biomedical Sciences, Li Ka Shing School of Medicine, The University of Hong Kong, Hong Kong, China
| | - Hongmin Zhang
- Department of Biology, and Shenzhen Key Laboratory of Cell Microenvironment, South University of Science and Technology of China, Shenzhen 518055, China
| | - Hon Cheung Lee
- School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen 518055, China
| | - Yong Juan Zhao
- School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen 518055, China
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Buchfellner A, Yurlova L, Nüske S, Scholz AM, Bogner J, Ruf B, Zolghadr K, Drexler SE, Drexler GA, Girst S, Greubel C, Reindl J, Siebenwirth C, Romer T, Friedl AA, Rothbauer U. A New Nanobody-Based Biosensor to Study Endogenous PARP1 In Vitro and in Live Human Cells. PLoS One 2016; 11:e0151041. [PMID: 26950694 PMCID: PMC4780744 DOI: 10.1371/journal.pone.0151041] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Accepted: 02/23/2016] [Indexed: 11/22/2022] Open
Abstract
Poly(ADP-ribose) polymerase 1 (PARP1) is a key player in DNA repair, genomic stability and cell survival and it emerges as a highly relevant target for cancer therapies. To deepen our understanding of PARP biology and mechanisms of action of PARP1-targeting anti-cancer compounds, we generated a novel PARP1-affinity reagent, active both in vitro and in live cells. This PARP1-biosensor is based on a PARP1-specific single-domain antibody fragment (~ 15 kDa), termed nanobody, which recognizes the N-terminus of human PARP1 with nanomolar affinity. In proteomic approaches, immobilized PARP1 nanobody facilitates quantitative immunoprecipitation of functional, endogenous PARP1 from cellular lysates. For cellular studies, we engineered an intracellularly functional PARP1 chromobody by combining the nanobody coding sequence with a fluorescent protein sequence. By following the chromobody signal, we were for the first time able to monitor the recruitment of endogenous PARP1 to DNA damage sites in live cells. Moreover, tracing of the sub-nuclear translocation of the chromobody signal upon treatment of human cells with chemical substances enables real-time profiling of active compounds in high content imaging. Due to its ability to perform as a biosensor at the endogenous level of the PARP1 enzyme, the novel PARP1 nanobody is a unique and versatile tool for basic and applied studies of PARP1 biology and DNA repair.
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Affiliation(s)
| | | | - Stefan Nüske
- Livestock Center of the Faculty of Veterinary Medicine, Ludwig Maximilians University, Munich, Germany
| | - Armin M. Scholz
- Livestock Center of the Faculty of Veterinary Medicine, Ludwig Maximilians University, Munich, Germany
| | | | - Benjamin Ruf
- ChromoTek GmbH, IZB, Planegg, Martinsried, Germany
| | | | - Sophie E. Drexler
- Department of Radiation Oncology, Ludwig Maximilians University, Munich, Germany
| | - Guido A. Drexler
- Department of Radiation Oncology, Ludwig Maximilians University, Munich, Germany
| | - Stefanie Girst
- Institute for Applied Physics and Metrology, Bundeswehr University Munich, Neubiberg, Germany
| | - Christoph Greubel
- Institute for Applied Physics and Metrology, Bundeswehr University Munich, Neubiberg, Germany
| | - Judith Reindl
- Institute for Applied Physics and Metrology, Bundeswehr University Munich, Neubiberg, Germany
| | - Christian Siebenwirth
- Department of Radiation Oncology, Klinikum rechts der Isar, Technical University Munich, Munich, Germany
| | - Tina Romer
- ChromoTek GmbH, IZB, Planegg, Martinsried, Germany
- * E-mail:
| | - Anna A. Friedl
- Department of Radiation Oncology, Ludwig Maximilians University, Munich, Germany
- Clinical Cooperation Group ‘Personalized Radiotherapy of Head and Neck Cancer’, Helmholtz Center Munich, Neuherberg, Germany
| | - Ulrich Rothbauer
- Natural and Medical Institute at the University of Tuebingen, Reutlingen, Germany
- Pharmaceutical Biotechnology, University of Tuebingen, Tuebingen, Germany
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Künzl F, Früholz S, Fäßler F, Li B, Pimpl P. Receptor-mediated sorting of soluble vacuolar proteins ends at the trans-Golgi network/early endosome. NATURE PLANTS 2016; 2:16017. [PMID: 27249560 DOI: 10.1038/nplants.2016.17] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Accepted: 02/01/2016] [Indexed: 05/03/2023]
Abstract
The sorting of soluble proteins for degradation in the vacuole is of vital importance in plant cells, and relies on the activity of vacuolar sorting receptors (VSRs). In the plant endomembrane system, VSRs bind vacuole-targeted proteins and facilitate their transport to the vacuole. Where exactly these interactions take place has remained controversial, however. Here, we examine the potential for VSR-ligand interactions in all compartments of the vacuolar transport system in tobacco mesophyll protoplasts. To do this, we developed compartment-specific VSR sensors that assemble as a result of a nanobody-epitope interaction, and monitored the degree of ligand binding by analysing Förster resonance energy transfer using fluorescence lifetime imaging microscopy (FRET-FLIM). We show that VSRs bind ligands in the endoplasmic reticulum (ER) and in the Golgi, but not in the trans-Golgi network/early endosome (TGN/EE) or multivesicular late endosomes, suggesting that the post-TGN/EE trafficking of ligands towards the vacuole is VSR independent. We verify this by showing that non-VSR-ligands are also delivered to the vacuole from the TGN/EE after endocytic uptake. We conclude that VSRs are required for the transport of ligands from the ER and the Golgi to the TGN/EE, and suggest that the onward transport to the vacuole occurs by default.
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Affiliation(s)
- Fabian Künzl
- Centre for Plant Molecular Biology (ZMBP), University of Tübingen, Auf der Morgenstelle 32, D-72076 Tübingen, Germany
| | - Simone Früholz
- Centre for Plant Molecular Biology (ZMBP), University of Tübingen, Auf der Morgenstelle 32, D-72076 Tübingen, Germany
| | - Florian Fäßler
- Centre for Plant Molecular Biology (ZMBP), University of Tübingen, Auf der Morgenstelle 32, D-72076 Tübingen, Germany
| | - Beibei Li
- Centre for Plant Molecular Biology (ZMBP), University of Tübingen, Auf der Morgenstelle 32, D-72076 Tübingen, Germany
| | - Peter Pimpl
- Centre for Plant Molecular Biology (ZMBP), University of Tübingen, Auf der Morgenstelle 32, D-72076 Tübingen, Germany
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Abstract
Actin is the central building block of the actin cytoskeleton, a highly regulated filamentous network enabling dynamic processes of cells and simultaneously providing structure. Mammals have six actin isoforms that are very conserved and thus share common functions. Tissue-specific expression in part underlies their differential roles, but actin isoforms also coexist in various cell types and tissues, suggesting specific functions and preferential interaction partners. Gene deletion models, antibody-based staining patterns, gene silencing effects, and the occurrence of isoform-specific mutations in certain diseases have provided clues for specificity on the subcellular level and its consequences on the organism level. Yet, the differential actin isoform functions are still far from understood in detail. Biochemical studies on the different isoforms in pure form are just emerging, and investigations in cells have to deal with a complex and regulated system, including compensatory actin isoform expression.
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Affiliation(s)
- Christophe Ampe
- Department of Biochemistry, Faculty of Medicine and Health Sciences, Ghent University, A. Baertsoenkaai 3, 9000, Ghent, Belgium.
| | - Marleen Van Troys
- Department of Biochemistry, Faculty of Medicine and Health Sciences, Ghent University, A. Baertsoenkaai 3, 9000, Ghent, Belgium
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Dyachok J, Paez-Garcia A, Yoo CM, Palanichelvam K, Blancaflor EB. Fluorescence Imaging of the Cytoskeleton in Plant Roots. Methods Mol Biol 2016; 1365:139-53. [PMID: 26498783 DOI: 10.1007/978-1-4939-3124-8_7] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
During the past two decades the use of live cytoskeletal probes has increased dramatically due to the introduction of the green fluorescent protein. However, to make full use of these live cell reporters it is necessary to implement simple methods to maintain plant specimens in optimal growing conditions during imaging. To image the cytoskeleton in living Arabidopsis roots, we rely on a system involving coverslips coated with nutrient supplemented agar where the seeds are directly germinated. This coverslip system can be conveniently transferred to the stage of a confocal microscope with minimal disturbance to the growth of the seedling. For roots with a larger diameter such as Medicago truncatula, seeds are first germinated in moist paper, grown vertically in between plastic trays, and roots mounted on glass slides for confocal imaging. Parallel with our live cell imaging approaches, we routinely process fixed plant material via indirect immunofluorescence. For these methods we typically use non-embedded vibratome-sectioned and whole mount permeabilized root tissue. The clearly defined developmental regions of the root provide us with an elegant system to further understand the cytoskeletal basis of plant development.
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Affiliation(s)
- Julia Dyachok
- McDermott Center for Human Growth & Development, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Ana Paez-Garcia
- Plant Biology Division, The Samuel Roberts Noble Foundation, Inc., 2510 Sam Noble Parkway, Ardmore, OK, 73401, USA
| | - Cheol-Min Yoo
- Plant Biology Division, The Samuel Roberts Noble Foundation, Inc., 2510 Sam Noble Parkway, Ardmore, OK, 73401, USA
| | | | - Elison B Blancaflor
- Plant Biology Division, The Samuel Roberts Noble Foundation, Inc., 2510 Sam Noble Parkway, Ardmore, OK, 73401, USA.
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42
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Real-time analysis of epithelial-mesenchymal transition using fluorescent single-domain antibodies. Sci Rep 2015; 5:13402. [PMID: 26292717 PMCID: PMC4544033 DOI: 10.1038/srep13402] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2015] [Accepted: 07/24/2015] [Indexed: 01/06/2023] Open
Abstract
Vimentin has become an important biomarker for epithelial-mesenchymal transition (EMT), a highly dynamic cellular process involved in the initiation of metastasis and cancer progression. To date there is no approach available to study endogenous vimentin in a physiological context. Here, we describe the selection and targeted modification of novel single-domain antibodies, so-called nanobodies, to trace vimentin in various cellular assays. Most importantly, we generated vimentin chromobodies by combining the binding moieties of the nanobodies with fluorescent proteins. Following chromobody fluorescence in a cancer-relevant cellular model, we were able for the first time to monitor and quantify dynamic changes of endogenous vimentin upon siRNA-mediated knockdown, induction with TGF-β and modification with Withaferin A by high-content imaging. This versatile approach allows detailed studies of the spatiotemporal organization of vimentin in living cells. It enables the identification of vimentin-modulating compounds, thereby providing the basis to screen for novel therapeutics affecting EMT.
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43
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Panza P, Maier J, Schmees C, Rothbauer U, Söllner C. Live imaging of endogenous protein dynamics in zebrafish using chromobodies. Development 2015; 142:1879-84. [PMID: 25968318 PMCID: PMC4440926 DOI: 10.1242/dev.118943] [Citation(s) in RCA: 69] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Chromobodies are intracellular nanoprobes that combine the specificity of antibodies with the convenience of live fluorescence imaging in a flexible, DNA-encoded reagent. Here, we present the first application of this technique to an intact living vertebrate organism. We generated zebrafish lines expressing chromobodies that trace the major cytoskeletal component actin and the cell cycle marker PCNA with spatial and temporal specificity. Using these chromobodies, we captured full localization dynamics of the endogenous antigens in different cell types and at different stages of development. For the first time, the chromobody technology enables live imaging of endogenous subcellular structures in an animal, with the remarkable advantage of avoiding target protein overexpression or tagging. In combination with improved chromobody selection systems, we anticipate a rapid adaptation of this technique to new intracellular antigens and model organisms, allowing the faithful description of cellular and molecular processes in their dynamic state. SUMMARY: Chromobodies - small, intracellular fluorescent antibodies - are used to trace endogenous antigens, without the need for direct protein tagging, in zebrafish embryos.
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Affiliation(s)
- Paolo Panza
- Max-Planck-Institut für Entwicklungsbiologie, Abteilung Genetik, Spemannstraße 35, Tübingen 72076, Germany
| | - Julia Maier
- Naturwissenschaftliches und Medizinisches Institut der Universität Tübingen, Markwiesenstraße 55, Reutlingen 72770, Germany Pharmazeutische Biotechnologie, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 8, Tübingen 72076, Germany
| | - Christian Schmees
- Naturwissenschaftliches und Medizinisches Institut der Universität Tübingen, Markwiesenstraße 55, Reutlingen 72770, Germany
| | - Ulrich Rothbauer
- Naturwissenschaftliches und Medizinisches Institut der Universität Tübingen, Markwiesenstraße 55, Reutlingen 72770, Germany Pharmazeutische Biotechnologie, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 8, Tübingen 72076, Germany
| | - Christian Söllner
- Max-Planck-Institut für Entwicklungsbiologie, Abteilung Genetik, Spemannstraße 35, Tübingen 72076, Germany
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Plessner M, Melak M, Chinchilla P, Baarlink C, Grosse R. Nuclear F-actin formation and reorganization upon cell spreading. J Biol Chem 2015; 290:11209-16. [PMID: 25759381 DOI: 10.1074/jbc.m114.627166] [Citation(s) in RCA: 184] [Impact Index Per Article: 20.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2014] [Indexed: 12/30/2022] Open
Abstract
We recently discovered signal-regulated nuclear actin network assembly. However, in contrast to cytoplasmic actin regulation, polymeric nuclear actin structures and functions remain only poorly understood. Here we describe a novel molecular tool to visualize real-time nuclear actin dynamics by targeting the Actin-Chromobody-TagGFP to the nucleus, thus establishing a nuclear Actin-Chromobody. Interestingly, we observe nuclear actin polymerization into dynamic filaments upon cell spreading and fibronectin stimulation, both of which appear to be triggered by integrin signaling. Furthermore, we show that nucleoskeletal proteins such as the LINC (linker of nucleoskeleton and cytoskeleton) complex and components of the nuclear lamina couple cell spreading or integrin activation by fibronectin to nuclear actin polymerization. Spreading-induced nuclear actin polymerization results in serum response factor (SRF)-mediated transcription through nuclear retention of myocardin-related transcription factor A (MRTF-A). Our results reveal a signaling pathway, which links integrin activation by extracellular matrix interaction to nuclear actin polymerization through the LINC complex, and therefore suggest a role for nuclear actin polymerization in the context of cellular adhesion and mechanosensing.
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Affiliation(s)
- Matthias Plessner
- From the Institute of Pharmacology, Biochemical-Pharmacological Center (BPC), University of Marburg, Karl-von-Frisch-Strasse 1, 35043 Marburg, Germany
| | - Michael Melak
- From the Institute of Pharmacology, Biochemical-Pharmacological Center (BPC), University of Marburg, Karl-von-Frisch-Strasse 1, 35043 Marburg, Germany
| | - Pilar Chinchilla
- From the Institute of Pharmacology, Biochemical-Pharmacological Center (BPC), University of Marburg, Karl-von-Frisch-Strasse 1, 35043 Marburg, Germany
| | - Christian Baarlink
- From the Institute of Pharmacology, Biochemical-Pharmacological Center (BPC), University of Marburg, Karl-von-Frisch-Strasse 1, 35043 Marburg, Germany
| | - Robert Grosse
- From the Institute of Pharmacology, Biochemical-Pharmacological Center (BPC), University of Marburg, Karl-von-Frisch-Strasse 1, 35043 Marburg, Germany
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