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Bonilla PA, Shrestha R. FLIM-FRET Protein-Protein Interaction Assay. Methods Mol Biol 2024; 2797:261-269. [PMID: 38570466 DOI: 10.1007/978-1-0716-3822-4_19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/05/2024]
Abstract
Fluorescence lifetime imaging performed under FRET conditions between two interacting molecules is a sensitive and robust way to quantify intermolecular interactions in cells. The fluorescence lifetime, an inherent property of the fluorophore, remains unaffected by factors such as concentration, laser intensity, and other photophysical artifacts. In the context of FLIM-FRET, the focus lies on measuring the fluorescence lifetime of the donor molecule, which diminishes upon interaction with a neighboring acceptor molecule. In this study, we present a step-by-step experimental protocol for applying FLIM-FRET to investigate protein-protein interactions involving various RAS isoforms and RAS effectors at the live cell's plasma membrane. By utilizing the FRET pair comprising enhanced green fluorescent protein (eGFP) and fluorescent mCherry, we demonstrate that the proximity and possible nanoclustering of eGFP-tagged KRAS4b G12D and mCherry-tagged KRAS4b WT led to a reduction in the donor eGFP's fluorescence lifetime. The donor lifetime of eGFP-tagged KRAS decreases even further when treated with a dimer-inducing small molecule, or in the presence of RAF proteins, suggesting a greater FRET efficiency, and thus less distance, between donor and acceptor.
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Affiliation(s)
- Pedro Andrade Bonilla
- NCI RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | - Rebika Shrestha
- NCI RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, MD, USA.
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2
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Khramtsov YV, Ulasov AV, Slastnikova TA, Rosenkranz AA, Lupanova TN, Georgiev GP, Sobolev AS. Modular Nanotransporters Delivering Biologically Active Molecules to the Surface of Mitochondria. Pharmaceutics 2023; 15:2687. [PMID: 38140028 PMCID: PMC10748074 DOI: 10.3390/pharmaceutics15122687] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Revised: 11/23/2023] [Accepted: 11/24/2023] [Indexed: 12/24/2023] Open
Abstract
Treatment of various diseases, in particular cancer, usually requires the targeting of biologically active molecules at a selected subcellular compartment. We modified our previously developed modular nanotransporters (MNTs) for targeting mitochondria. The new MNTs are capable of binding to the protein predominantly localized on the outer mitochondrial membrane, Keap1. These MNTs possessing antiKeap1 monobody co-localize with mitochondria upon addition to the cells. They efficiently interact with Keap1 both in solution and within living cells. A conjugate of the MNT with a photosensitizer, chlorin e6, demonstrated significantly higher photocytotoxicity than chlorin e6 alone. We assume that MNTs of this kind can improve efficiency of therapeutic photosensitizers and radionuclides emitting short-range particles.
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Affiliation(s)
- Yuri V. Khramtsov
- Laboratory of Molecular Genetics of Intracellular Transport, Institute of Gene Biology of Russian Academy of Sciences, 34/5 Vavilov St., 119334 Moscow, Russia; (Y.V.K.); (A.V.U.); (T.A.S.); (A.A.R.); (T.N.L.); (G.P.G.)
| | - Alexey V. Ulasov
- Laboratory of Molecular Genetics of Intracellular Transport, Institute of Gene Biology of Russian Academy of Sciences, 34/5 Vavilov St., 119334 Moscow, Russia; (Y.V.K.); (A.V.U.); (T.A.S.); (A.A.R.); (T.N.L.); (G.P.G.)
| | - Tatiana A. Slastnikova
- Laboratory of Molecular Genetics of Intracellular Transport, Institute of Gene Biology of Russian Academy of Sciences, 34/5 Vavilov St., 119334 Moscow, Russia; (Y.V.K.); (A.V.U.); (T.A.S.); (A.A.R.); (T.N.L.); (G.P.G.)
| | - Andrey A. Rosenkranz
- Laboratory of Molecular Genetics of Intracellular Transport, Institute of Gene Biology of Russian Academy of Sciences, 34/5 Vavilov St., 119334 Moscow, Russia; (Y.V.K.); (A.V.U.); (T.A.S.); (A.A.R.); (T.N.L.); (G.P.G.)
- Faculty of Biology, Lomonosov Moscow State University, 1-12 Leninskie Gory St., 119234 Moscow, Russia
| | - Tatiana N. Lupanova
- Laboratory of Molecular Genetics of Intracellular Transport, Institute of Gene Biology of Russian Academy of Sciences, 34/5 Vavilov St., 119334 Moscow, Russia; (Y.V.K.); (A.V.U.); (T.A.S.); (A.A.R.); (T.N.L.); (G.P.G.)
| | - Georgii P. Georgiev
- Laboratory of Molecular Genetics of Intracellular Transport, Institute of Gene Biology of Russian Academy of Sciences, 34/5 Vavilov St., 119334 Moscow, Russia; (Y.V.K.); (A.V.U.); (T.A.S.); (A.A.R.); (T.N.L.); (G.P.G.)
| | - Alexander S. Sobolev
- Laboratory of Molecular Genetics of Intracellular Transport, Institute of Gene Biology of Russian Academy of Sciences, 34/5 Vavilov St., 119334 Moscow, Russia; (Y.V.K.); (A.V.U.); (T.A.S.); (A.A.R.); (T.N.L.); (G.P.G.)
- Faculty of Biology, Lomonosov Moscow State University, 1-12 Leninskie Gory St., 119234 Moscow, Russia
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3
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Martin‐Fernandez ML. A perspective of fluorescence microscopy for cellular structural biology with EGFR as witness. J Microsc 2023; 291:73-91. [PMID: 36282005 PMCID: PMC10952613 DOI: 10.1111/jmi.13151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Revised: 09/20/2022] [Accepted: 10/11/2022] [Indexed: 10/31/2022]
Abstract
The epidermal growth factor receptor (EGFR) is a poster child for the understanding of receptor behaviour, and of paramount importance to cell function and human health. Cloned almost forty years ago, the interest in EGFR's structure/function relationships remains unabated, not least because changes in oncogenic EGFR mutants are key drivers of the formation of lung and brain tumours. The structure of the assemblies formed by EGFR have been comprehensibly investigated by techniques such as high-resolution X-ray crystallography, NMR and all-atom molecular dynamics (MD) simulations. However, the complexity embedded in the portfolio of EGFR states that are only possible in the physiological environment of cells has often proved refractory to cell-free structural methods. Conversely, some key inroads made by quantitative fluorescence microscopy and super-resolution have depended on exploiting the wealth of structures available. Here, a brief personal perspective is provided on how quantitative fluorescence microscopy and super-resolution methods have cross-fertilised with cell-free-derived EGFR structural information. I primarily discuss areas in which my research group has made a contribution to fill gaps in EGFR's cellular structural biology and towards developing new tools to investigate macromolecular assemblies in cells.
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Affiliation(s)
- M. L. Martin‐Fernandez
- Central Laser FacilityScience and Technology Facilities Council, Rutherford Appleton LaboratoryDidcotUK
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4
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Dupont C, Chahar D, Trullo A, Gostan T, Surcis C, Grimaud C, Fisher D, Feil R, Llères D. Evidence for low nanocompaction of heterochromatin in living embryonic stem cells. EMBO J 2023:e110286. [PMID: 37082862 DOI: 10.15252/embj.2021110286] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 03/22/2023] [Accepted: 03/29/2023] [Indexed: 04/22/2023] Open
Abstract
Despite advances in the identification of chromatin regulators and genome interactions, the principles of higher-order chromatin structure have remained elusive. Here, we applied FLIM-FRET microscopy to analyse, in living cells, the spatial organisation of nanometre range proximity between nucleosomes, which we called "nanocompaction." Both in naive embryonic stem cells (ESCs) and in ESC-derived epiblast-like cells (EpiLCs), we find that, contrary to expectations, constitutive heterochromatin is much less compacted than bulk chromatin. The opposite was observed in fixed cells. HP1α knockdown increased nanocompaction in living ESCs, but this was overridden by loss of HP1β, indicating the existence of a dynamic HP1-dependent low compaction state in pluripotent cells. Depletion of H4K20me2/3 abrogated nanocompaction, while increased H4K20me3 levels accompanied the nuclear reorganisation during EpiLCs induction. Finally, the knockout of the nuclear cellular-proliferation marker Ki-67 strongly reduced both interphase and mitotic heterochromatin nanocompaction in ESCs. Our data indicate that, contrary to prevailing models, heterochromatin is not highly compacted at the nanoscale but resides in a dynamic low nanocompaction state that depends on H4K20me2/3, the balance between HP1 isoforms, and Ki-67.
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Affiliation(s)
- Claire Dupont
- Institute of Molecular Genetics of Montpellier (IGMM), CNRS, University of Montpellier, Montpellier, France
| | - Dhanvantri Chahar
- Institute of Molecular Genetics of Montpellier (IGMM), CNRS, University of Montpellier, Montpellier, France
| | - Antonio Trullo
- Institute of Molecular Genetics of Montpellier (IGMM), CNRS, University of Montpellier, Montpellier, France
| | - Thierry Gostan
- Institute of Molecular Genetics of Montpellier (IGMM), CNRS, University of Montpellier, Montpellier, France
| | - Caroline Surcis
- Institute of Molecular Genetics of Montpellier (IGMM), CNRS, University of Montpellier, Montpellier, France
| | - Charlotte Grimaud
- Institute of Human Genetics (IGH), CNRS, University of Montpellier, Montpellier, France
| | - Daniel Fisher
- Institute of Molecular Genetics of Montpellier (IGMM), CNRS, University of Montpellier, Montpellier, France
| | - Robert Feil
- Institute of Molecular Genetics of Montpellier (IGMM), CNRS, University of Montpellier, Montpellier, France
| | - David Llères
- Institute of Molecular Genetics of Montpellier (IGMM), CNRS, University of Montpellier, Montpellier, France
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Legartová S, Fagherazzi P, Goswami P, Brazda V, Lochmanová G, Koutná I, Bártová E. Irradiation potentiates p53 phosphorylation and p53 binding to the promoter and coding region of the TP53 gene. Biochimie 2023; 204:154-168. [PMID: 36167255 DOI: 10.1016/j.biochi.2022.09.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Revised: 08/08/2022] [Accepted: 09/21/2022] [Indexed: 01/12/2023]
Abstract
An essential factor of the DNA damage response is 53BP1, a multimeric protein that inhibits the resection-dependent double-strand break (DBS) repair. The p53 protein is a tumor suppressor known as a guardian of the genome. Although the interaction between 53BP1 and its p53 partner is well-known in regulating gene expression, a question remains whether genome injury can affect the interaction between 53BP1 and p53 proteins or p53 binding to DNA. Here, using mass spectrometry, we determine post-translational modifications and interaction properties of 53BP1 and p53 proteins in non-irradiated and γ-irradiated cells. In addition, we used Atomic Force Microscopy (AFM) and Fluorescent Lifetime Imaging Microscopy combined with Fluorescence Resonance Energy Transfer (FLIM-FRET) for studies of p53 binding to DNA. Also, we used local laser microirradiation as a tool of advanced confocal microscopy, showing selected protein accumulation at locally induced DNA lesions. We observed that 53BP1 and p53 proteins accumulate at microirradiated chromatin but with distinct kinetics. The density of 53BP1 (53BP1pS1778) phosphorylated form was lower in DNA lesions than in the non-specified form. By mass spectrometry, we found 22 phosphorylations, 4 acetylation sites, and methylation of arginine 1355 within the DNA-binding domain of the 53BP1 protein (aa1219-1711). The p53 protein was phosphorylated on 8 amino acids and acetylated on the N-terminal domain. Post-translational modifications (PTMs) of 53BP1 were not changed in cells exposed to γ-radiation, while γ-rays increased the level of S6ph and S15ph in p53. Interaction analysis showed that 53BP1 and p53 proteins have 54 identical interaction protein partners, and AFM revealed that p53 binds to both non-specific and TP53-specific sequences (AGACATGCCTA GGCATGTCT). Irradiation by γ-rays enhanced the density of the p53 protein at the AGACATGCCTAGGCATGTCT region, and the binding of p53 S15ph to the TP53 promoter was potentiated in irradiated cells. These findings show that γ-irradiation, in general, strengthens the binding of phosphorylated p53 protein to the encoding gene.
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Affiliation(s)
- Soňa Legartová
- Department of Cell Biology and Epigenetics, Institute of Biophysics, Academy of Sciences of the Czech Republic, Brno, Czech Republic.
| | - Paolo Fagherazzi
- Department of Cell Biology and Epigenetics, Institute of Biophysics, Academy of Sciences of the Czech Republic, Brno, Czech Republic; Department of Experimental Biology, Faculty of Science, Masaryk University, Brno, Czech Republic.
| | - Pratik Goswami
- Department of Biophysical Chemistry and Molecular Oncology, Institute of Biophysics, Academy of Sciences of the Czech Republic, Brno, Czech Republic; National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Brno, Czech Republic.
| | - Vaclav Brazda
- Department of Biophysical Chemistry and Molecular Oncology, Institute of Biophysics, Academy of Sciences of the Czech Republic, Brno, Czech Republic.
| | - Gabriela Lochmanová
- Central European Institute of Technology, Masaryk University, Brno, Czech Republic; National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Brno, Czech Republic.
| | - Irena Koutná
- The International Clinical Research Center of St. Anne's University Hospital in Brno (FNUSA-ICRC), Pekařská 53, 656 91, Brno, Czech Republic
| | - Eva Bártová
- Department of Cell Biology and Epigenetics, Institute of Biophysics, Academy of Sciences of the Czech Republic, Brno, Czech Republic.
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6
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Carrillo R, Feldeverd E, Christopher DA. The Use of Fluorescent Protein Fusions to Monitor the Unfolded Protein Response and Protein Foldase-Substrate Interactions in Plant Protoplasts. Methods Mol Biol 2022; 2378:69-81. [PMID: 34985694 DOI: 10.1007/978-1-0716-1732-8_5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Endoplasmic reticulum (ER) stress and the resulting unfolded protein response (UPR) are critical stress response pathways in eukaryotes. To study these types of interactions in plants, a wide range of methods have been used, including generation of transgenic plants, subcellular immunolocalization of protein foldases, and co-immunoprecipitation (co-IP) assays. Although these more time-consuming methods have been successfully implemented, there is a need for a versatile and rapid in vivo system to investigate ER stress and UPR. Here, we describe a transient expression system that uses plant protoplasts to define in vivo subcellular localizations and protein-protein interactions of protein foldases and their substrates fused to fluorescent protein reporters. This accurate and robust assay utilizes a variety of analyses, such as subcellular localization, FLIM-FRET, co-IP, mutagenesis, and RT-PCR in the genetically amenable Arabidopsis model system. We demonstrate the methodology by using the representative protein foldase, protein disulfide isomerase-9 (PDI9), as well as subcellular markers, secretory proteins, and dithiothreitol (DTT)-mediated induction of the UPR as monitored by RT-PCR. Together, these methods yield reliable high output results for investigating subcellular localization and protein-protein interactions in plants to decipher the UPR pathways.
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Affiliation(s)
- Rina Carrillo
- Department of Molecular Biosciences & Bioengineering, University of Hawaii, Honolulu, HI, USA
| | - Elizabeth Feldeverd
- Department of Molecular Biosciences & Bioengineering, University of Hawaii, Honolulu, HI, USA
| | - David A Christopher
- Department of Molecular Biosciences & Bioengineering, University of Hawaii, Honolulu, HI, USA.
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7
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Bajar BT, Guan X, Lam A, Lin MZ, Yasuda R, Laviv T, Chu J. FRET Imaging of Rho GTPase Activity with Red Fluorescent Protein-Based FRET Pairs. Methods Mol Biol 2022; 2438:31-43. [PMID: 35147933 PMCID: PMC9976416 DOI: 10.1007/978-1-0716-2035-9_2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
With the development of fluorescent proteins (FPs) and advanced optical microscopy techniques, Förster or fluorescence resonance energy transfer (FRET) has become a powerful tool for real-time noninvasive visualization of a variety of biological processes, including kinase activities, with high spatiotemporal resolution in living cells and organisms. FRET can be detected in appropriately configured microscopes as changes in fluorescence intensity, lifetime, and anisotropy. Here, we describe the preparation of samples expressing FP-based FRET sensors for RhoA kinase, intensity- and lifetime-based FRET imaging, and postimaging data analysis.
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Affiliation(s)
- Bryce T Bajar
- Department of Biological Chemistry, Medical Scientist Training Program, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA
| | - Xinmeng Guan
- Guangdong Provincial Key Laboratory of Biomedical Optical Imaging Technology & Center for Biomedical Optics and Molecular Imaging, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Amy Lam
- Departments of Neurobiology and Bioengineering, Stanford University, Stanford, CA, USA
| | - Michael Z Lin
- Departments of Neurobiology and Bioengineering, Stanford University, Stanford, CA, USA
| | - Ryohei Yasuda
- Neuronal Signal Transduction Group, Max Planck Florida Institute for Neuroscience, Jupiter, FL, USA
| | - Tal Laviv
- Neuronal Signal Transduction Group, Max Planck Florida Institute for Neuroscience, Jupiter, FL, USA.
- Department of Physiology and Pharmacology, Sackler School of Medicine and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel.
| | - Jun Chu
- Guangdong Provincial Key Laboratory of Biomedical Optical Imaging Technology & Center for Biomedical Optics and Molecular Imaging, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China.
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8
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Holoubek A, Strachotová D, Otevřelová P, Röselová P, Heřman P, Brodská B. AML-Related NPM Mutations Drive p53 Delocalization into the Cytoplasm with Possible Impact on p53-Dependent Stress Response. Cancers (Basel) 2021; 13:cancers13133266. [PMID: 34209894 PMCID: PMC8269334 DOI: 10.3390/cancers13133266] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Revised: 06/22/2021] [Accepted: 06/23/2021] [Indexed: 11/17/2022] Open
Abstract
Simple Summary Nucleophosmin (NPM) is one of the most abundant nucleolar proteins and its mutations frequently occur in acute myeloid leukemia (AML). The mutations cause aberrant cytoplasmic localization of mutated protein (NPMmut) and often mediate dislocation of NPM interaction partners. Tumor suppressor p53 is known to interact with NPM in response to genotoxic stress and its cytoplasmic localization is an unfavorable prognostic factor in cancers. This study aims to characterize the NPM-p53 interaction and to elucidate the effect of the NPM mutations on p53 localization and expression in live cells. In addition, the cellular dynamics of NPMmut and p53 after treatment with nuclear export inhibitor Selinexor is described and the mechanism of the Selinexor action proposed. Our results contribute to a better understanding of the oncogenic potential of NPM mutations. Abstract Nucleophosmin (NPM) interaction with tumor suppressor p53 is a part of a complex interaction network and considerably affects cellular stress response. The impact of NPM1 mutations on its interaction with p53 has not been investigated yet, although consequences of NPMmut-induced p53 export to the cytoplasm are important for understanding the oncogenic potential of these mutations. We investigated p53-NPM interaction in live HEK-293T cells by FLIM-FRET and in cell lysates by immunoprecipitation. eGFP lifetime-photoconversion was used to follow redistribution dynamics of NPMmut and p53 in Selinexor-treated cells. We confirmed the p53-NPMwt interaction in intact cells and newly documented that this interaction is not compromised by the NPM mutation causing displacement of p53 to the cytoplasm. Moreover, the interaction was not abolished for non-oligomerizing NPM variants with truncated oligomerization domain, suggesting that oligomerization is not essential for interaction of NPM forms with p53. Inhibition of the nuclear exporter XPO1 by Selinexor caused expected nuclear relocalization of both NPMmut and p53. However, significantly different return rates of these proteins indicate nontrivial mechanism of p53 and NPMmut cellular trafficking. The altered p53 regulation in cells expressing NPMmut offers improved understanding to help investigational strategies targeting these mutations.
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Affiliation(s)
- Aleš Holoubek
- Department of Proteomics, Institute of Hematology and Blood Transfusion, U Nemocnice 1, 128 20 Prague, Czech Republic; (A.H.); (P.O.); (P.R.)
| | - Dita Strachotová
- Institute of Physics, Faculty of Mathematics and Physics, Charles University, Ke Karlovu 5, 121 16 Prague, Czech Republic;
| | - Petra Otevřelová
- Department of Proteomics, Institute of Hematology and Blood Transfusion, U Nemocnice 1, 128 20 Prague, Czech Republic; (A.H.); (P.O.); (P.R.)
| | - Pavla Röselová
- Department of Proteomics, Institute of Hematology and Blood Transfusion, U Nemocnice 1, 128 20 Prague, Czech Republic; (A.H.); (P.O.); (P.R.)
| | - Petr Heřman
- Institute of Physics, Faculty of Mathematics and Physics, Charles University, Ke Karlovu 5, 121 16 Prague, Czech Republic;
- Correspondence: (P.H.); (B.B.); Tel.: +420-951-551-461 (P.H.); +420-221-977-354 (B.B.)
| | - Barbora Brodská
- Department of Proteomics, Institute of Hematology and Blood Transfusion, U Nemocnice 1, 128 20 Prague, Czech Republic; (A.H.); (P.O.); (P.R.)
- Correspondence: (P.H.); (B.B.); Tel.: +420-951-551-461 (P.H.); +420-221-977-354 (B.B.)
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9
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Fesquet D, Llères D, Grimaud C, Viganò C, Méchali F, Boulon S, Coux O, Bonne-Andrea C, Baldin V. The 20S proteasome activator PA28γ controls the compaction of chromatin. J Cell Sci 2021; 134:134/3/jcs257717. [PMID: 33526472 DOI: 10.1242/jcs.257717] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Accepted: 12/03/2020] [Indexed: 12/16/2022] Open
Abstract
PA28γ (also known as PSME3), a nuclear activator of the 20S proteasome, is involved in the degradation of several proteins regulating cell growth and proliferation and in the dynamics of various nuclear bodies, but its precise cellular functions remain unclear. Here, using a quantitative FLIM-FRET based microscopy assay monitoring close proximity between nucleosomes in living human cells, we show that PA28γ controls chromatin compaction. We find that its depletion induces a decompaction of pericentromeric heterochromatin, which is similar to what is observed upon the knockdown of HP1β (also known as CBX1), a key factor of the heterochromatin structure. We show that PA28γ is present at HP1β-containing repetitive DNA sequences abundant in heterochromatin and, importantly, that HP1β on its own is unable to drive chromatin compaction without the presence of PA28γ. At the molecular level, we show that this novel function of PA28γ is independent of its stable interaction with the 20S proteasome, and most likely depends on its ability to maintain appropriate levels of H3K9me3 and H4K20me3, histone modifications that are involved in heterochromatin formation. Overall, our results implicate PA28γ as a key factor involved in the regulation of the higher order structure of chromatin.
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Affiliation(s)
- Didier Fesquet
- Centre de Recherche de Biologie cellulaire de Montpellier (CRBM), Université de Montpellier, CNRS, 34293 Montpellier, France
| | - David Llères
- Institut de Génétique Moléculaire de Montpellier (IGMM), Université de Montpellier, CNRS, 34293 Montpellier, France
| | - Charlotte Grimaud
- Institut de Recherche en Cancérologie de Montpellier (IRCM), INSERM U1194, Institut Régional du Cancer (ICM), Université de Montpellier, CNRS Route de Mende, 34293 Montpellier, France
| | - Cristina Viganò
- Centre de Recherche de Biologie cellulaire de Montpellier (CRBM), Université de Montpellier, CNRS, 34293 Montpellier, France
| | - Francisca Méchali
- Centre de Recherche de Biologie cellulaire de Montpellier (CRBM), Université de Montpellier, CNRS, 34293 Montpellier, France
| | - Séverine Boulon
- Centre de Recherche de Biologie cellulaire de Montpellier (CRBM), Université de Montpellier, CNRS, 34293 Montpellier, France
| | - Olivier Coux
- Centre de Recherche de Biologie cellulaire de Montpellier (CRBM), Université de Montpellier, CNRS, 34293 Montpellier, France
| | - Catherine Bonne-Andrea
- Centre de Recherche de Biologie cellulaire de Montpellier (CRBM), Université de Montpellier, CNRS, 34293 Montpellier, France
| | - Véronique Baldin
- Centre de Recherche de Biologie cellulaire de Montpellier (CRBM), Université de Montpellier, CNRS, 34293 Montpellier, France
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10
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Martin-Fernandez ML. A brief history of the octopus imaging facility to celebrate its 10th anniversary. J Microsc 2020; 281:3-15. [PMID: 33111321 DOI: 10.1111/jmi.12974] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Revised: 10/19/2020] [Accepted: 10/23/2020] [Indexed: 11/27/2022]
Abstract
Octopus (Optics Clustered to OutPut Unique Solutions) celebrated in June 2020 its 10th birthday. Based at Harwell, near Oxford, Octopus is an open access, peer reviewed, national imaging facility that offers successful U.K. applicants supported access to single molecule imaging, confocal microscopy, several flavours of superresolution imaging, light sheet microscopy, optical trapping and cryoscanning electron microscopy. Managed by a multidisciplinary team, Octopus has so far assisted >100 groups of U.K. and international researchers. Cross-fertilisation across fields proved to be a strong propeller of success underpinned by combining access to top-end instrumentation with a strong programme of imaging hardware and software developments. How Octopus was born, and highlights of the multidisciplinary output produced during its 10-year journey are reviewed below, with the aim of celebrating a myriad of collaborations with the U.K. scientific community, and reflecting on their scientific and societal impact.
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Affiliation(s)
- M L Martin-Fernandez
- Central Laser Facility, Research Complex at Harwell, Rutherford Appleton Laboratory, Harwell, Didcot, Oxford, U.K
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11
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Herbette M, Robert V, Bailly A, Gely L, Feil R, Llères D, Palladino F. A Role for Caenorhabditis elegans COMPASS in Germline Chromatin Organization. Cells 2020; 9:cells9092049. [PMID: 32911802 PMCID: PMC7565041 DOI: 10.3390/cells9092049] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Revised: 09/02/2020] [Accepted: 09/03/2020] [Indexed: 02/07/2023] Open
Abstract
Deposition of histone H3 lysine 4 (H3K4) methylation at promoters is catalyzed by the SET1/COMPASS complex and is associated with context-dependent effects on gene expression and local changes in chromatin organization. The role of SET1/COMPASS in shaping chromosome architecture has not been investigated. Here we used Caenorhabditis elegans to address this question through a live imaging approach and genetic analysis. Using quantitative FRET (Förster resonance energy transfer)-based fluorescence lifetime imaging microscopy (FLIM) on germ cells expressing histones eGFP-H2B and mCherry-H2B, we find that SET1/COMPASS influences meiotic chromosome organization, with marked effects on the close proximity between nucleosomes. We further show that inactivation of set-2, encoding the C. elegans SET1 homologue, or CFP-1, encoding the chromatin targeting subunit of COMPASS, enhances germline chromosome organization defects and sterility of condensin-II depleted animals. set-2 loss also aggravates germline defects resulting from conditional inactivation of topoisomerase II, another structural component of chromosomes. Expression profiling of set-2 mutant germlines revealed only minor transcriptional changes, suggesting that the observed effects are at least partly independent of transcription. Altogether, our results are consistent with a role for SET1/COMPASS in shaping meiotic chromosomes in C. elegans, together with the non-histone proteins condensin-II and topoisomerase. Given the high degree of conservation, our findings expand the range of functions attributed to COMPASS and suggest a broader role in genome organization in different species.
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Affiliation(s)
- Marion Herbette
- Laboratory of Biology and Modeling of the Cell (LBMC), CNRS, Ecole Normale Supérieure de Lyon, Université de Lyon, 69007 Lyon, France; (M.H.); (V.R.); (L.G.)
| | - Valérie Robert
- Laboratory of Biology and Modeling of the Cell (LBMC), CNRS, Ecole Normale Supérieure de Lyon, Université de Lyon, 69007 Lyon, France; (M.H.); (V.R.); (L.G.)
| | - Aymeric Bailly
- Centre de Recherche en Biologie cellulaire de Montpellier, CRBM, CNRS, University of Montpellier, 34090 Montpellier, France;
| | - Loïc Gely
- Laboratory of Biology and Modeling of the Cell (LBMC), CNRS, Ecole Normale Supérieure de Lyon, Université de Lyon, 69007 Lyon, France; (M.H.); (V.R.); (L.G.)
| | - Robert Feil
- Institute of Molecular Genetics of Montpellier (IGMM), CNRS, University of Montpellier, 34090 Montpellier, France; (R.F.); (D.L.)
| | - David Llères
- Institute of Molecular Genetics of Montpellier (IGMM), CNRS, University of Montpellier, 34090 Montpellier, France; (R.F.); (D.L.)
| | - Francesca Palladino
- Laboratory of Biology and Modeling of the Cell (LBMC), CNRS, Ecole Normale Supérieure de Lyon, Université de Lyon, 69007 Lyon, France; (M.H.); (V.R.); (L.G.)
- Correspondence: ; Tel.: +33-047-2728-126
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12
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Mystek P, Rysiewicz B, Gregrowicz J, Dziedzicka-Wasylewska M, Polit A. Gγ and Gα Identity Dictate a G-Protein Heterotrimer Plasma Membrane Targeting. Cells 2019; 8:E1246. [PMID: 31614907 PMCID: PMC6829862 DOI: 10.3390/cells8101246] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Revised: 10/10/2019] [Accepted: 10/11/2019] [Indexed: 12/18/2022] Open
Abstract
Heterotrimeric G-proteins along with G-protein-coupled receptors (GPCRs) regulate many biochemical functions by relaying the information from the plasma membrane to the inside of the cell. The lipid modifications of Gα and Gγ subunits, together with the charged regions on the membrane interaction surface, provide a peculiar pattern for various heterotrimeric complexes. In a previous study, we found that Gαs and Gαi3 prefer different types of membrane-anchor and subclass-specific lipid domains. In the present report, we examine the role of distinct Gγ subunits in the membrane localization and spatiotemporal dynamics of Gαs and Gαi3 heterotrimers. We characterized lateral diffusion and G-protein subunit interactions in living cells using fluorescence recovery after photobleaching (FRAP) microscopy and fluorescence resonance energy transfer (FRET) detected by fluorescence lifetime imaging microscopy (FLIM), respectively. The interaction of Gγ subunits with specific lipids was confirmed, and thus the modulation of heterotrimeric G-protein localization. However, the Gα subunit also modulates trimer localization, and so the membrane distribution of heterotrimeric G-proteins is not dependent on Gγ only.
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Affiliation(s)
- Paweł Mystek
- Department of Physical Biochemistry, Faculty of Biochemistry Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, 30-387 Kraków, Poland.
| | - Beata Rysiewicz
- Department of Physical Biochemistry, Faculty of Biochemistry Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, 30-387 Kraków, Poland.
| | - Jan Gregrowicz
- Department of Physical Biochemistry, Faculty of Biochemistry Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, 30-387 Kraków, Poland.
| | - Marta Dziedzicka-Wasylewska
- Department of Physical Biochemistry, Faculty of Biochemistry Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, 30-387 Kraków, Poland.
| | - Agnieszka Polit
- Department of Physical Biochemistry, Faculty of Biochemistry Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, 30-387 Kraków, Poland.
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Legartová S, Lochmanová G, Zdráhal Z, Kozubek S, Šponer J, Krepl M, Pokorná P, Bártová E. DNA Damage Changes Distribution Pattern and Levels of HP1 Protein Isoforms in the Nucleolus and Increases Phosphorylation of HP1β-Ser88. Cells 2019; 8:E1097. [PMID: 31533340 DOI: 10.3390/cells8091097] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2019] [Revised: 09/10/2019] [Accepted: 09/10/2019] [Indexed: 12/28/2022] Open
Abstract
The family of heterochromatin protein 1 (HP1) isoforms is essential for chromatin packaging, regulation of gene expression, and repair of damaged DNA. Here we document that γ-radiation reduced the number of HP1α-positive foci, but not HP1β and HP1γ foci, located in the vicinity of the fibrillarin-positive region of the nucleolus. The additional analysis confirmed that γ-radiation has the ability to significantly decrease the level of HP1α in rDNA promoter and rDNA encoding 28S rRNA. By mass spectrometry, we showed that treatment by γ-rays enhanced the HP1β serine 88 phosphorylation (S88ph), but other analyzed modifications of HP1β, including S161ph/Y163ph, S171ph, and S174ph, were not changed in cells exposed to γ-rays or treated by the HDAC inhibitor (HDACi). Interestingly, a combination of HDACi and γ-radiation increased the level of HP1α and HP1γ. The level of HP1β remained identical before and after the HDACi/γ-rays treatment, but HDACi strengthened HP1β interaction with the KRAB-associated protein 1 (KAP1) protein. Conversely, HP1γ did not interact with KAP1, although approximately 40% of HP1γ foci co-localized with accumulated KAP1. Especially HP1γ foci at the periphery of nucleoli were mostly absent of KAP1. Together, DNA damage changed the morphology, levels, and interaction properties of HP1 isoforms. Also, γ-irradiation-induced hyperphosphorylation of the HP1β protein; thus, HP1β-S88ph could be considered as an important marker of DNA damage.
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Saleeb RS, Kavanagh DM, Dun AR, Dalgarno PA, Duncan RR. A VPS33A-binding motif on syntaxin 17 controls autophagy completion in mammalian cells. J Biol Chem 2019; 294:4188-4201. [PMID: 30655294 PMCID: PMC6422071 DOI: 10.1074/jbc.ra118.005947] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Revised: 12/21/2018] [Indexed: 01/24/2023] Open
Abstract
Autophagy is an intracellular degradation pathway that transports cytoplasmic material to the lysosome for hydrolysis. It is completed by SNARE-mediated fusion of the autophagosome and endolysosome membranes. This process must be carefully regulated to maintain the organization of the membrane system and prevent mistargeted degradation. As yet, models of autophagosomal fusion have not been verified within a cellular context because of difficulties with assessing protein interactions in situ Here, we used high-resolution fluorescence lifetime imaging (FLIM)-FRET of HeLa cells to identify protein interactions within the spatiotemporal framework of the cell. We show that autophagosomal syntaxin 17 (Stx17) heterotrimerizes with synaptosome-associated protein 29 (SNAP29) and vesicle-associated membrane protein 7 (VAMP7) in situ, highlighting a functional role for VAMP7 in autophagosome clearance that has previously been sidelined in favor of a role for VAMP8. Additionally, we identified multimodal regulation of SNARE assembly by the Sec1/Munc18 (SM) protein VPS33A, mirroring other syntaxin-SM interactions and therefore suggesting a unified model of SM regulation. Contrary to current theoretical models, we found that the Stx17 N-peptide appears to interact in a positionally conserved, but mechanistically divergent manner with VPS33A, providing a late "go, no-go" step for autophagic fusion via a phosphoserine master-switch. Our findings suggest that Stx17 fusion competency is regulated by a phosphosite in its N-peptide, representing a previously unknown regulatory step in mammalian autophagy.
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Affiliation(s)
- Rebecca S Saleeb
- From the Edinburgh Super-Resolution Imaging Consortium, Institute of Biological Chemistry, Biophysics, and Bioengineering, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, United Kingdom
| | - Deirdre M Kavanagh
- From the Edinburgh Super-Resolution Imaging Consortium, Institute of Biological Chemistry, Biophysics, and Bioengineering, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, United Kingdom
| | - Alison R Dun
- From the Edinburgh Super-Resolution Imaging Consortium, Institute of Biological Chemistry, Biophysics, and Bioengineering, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, United Kingdom
| | - Paul A Dalgarno
- From the Edinburgh Super-Resolution Imaging Consortium, Institute of Biological Chemistry, Biophysics, and Bioengineering, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, United Kingdom
| | - Rory R Duncan
- From the Edinburgh Super-Resolution Imaging Consortium, Institute of Biological Chemistry, Biophysics, and Bioengineering, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, United Kingdom
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15
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Abstract
The Bcl-2 proteins control cell death via interchanging interactions within the Bcl-2 family. Fluorescence lifetime imaging microscopy (FLIM) is used to detect Förster resonance energy transfer (FRET) between two fluorescent-fusion proteins in live cells. FLIM-FRET has been used to detect specific interactions and their disruption, for Bcl-2 family proteins. To date, this has been possible only in low throughput, due to the time required for serial data acquisition. We developed an automated optical system with eight parallel detectors for rapid and efficient data collection. Here we describe how to use this system for FLIM-FRET imaging of Bcl-2 family protein interactions in a 384-well plate format.
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Affiliation(s)
- Elizabeth J Osterlund
- Department of Biochemistry, University of Toronto, Toronto, ON, Canada.,Sunnybrook Research Institute, Toronto, ON, Canada
| | - Nehad Hirmiz
- Sunnybrook Research Institute, Toronto, ON, Canada.,School of Biomedical Engineering, McMaster University, Hamilton, ON, Canada
| | | | - David W Andrews
- Department of Biochemistry, University of Toronto, Toronto, ON, Canada. .,Sunnybrook Research Institute, Toronto, ON, Canada.
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16
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Zherdeva V, Kazachkina NI, Shcheslavskiy V, Savitsky AP. Long-term fluorescence lifetime imaging of a genetically encoded sensor for caspase-3 activity in mouse tumor xenografts. J Biomed Opt 2018; 23:1-11. [PMID: 29500873 DOI: 10.1117/1.jbo.23.3.035002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Accepted: 02/01/2018] [Indexed: 06/08/2023]
Abstract
Caspase-3 is known for its role in apoptosis and programmed cell death regulation. We detected caspase-3 activation in vivo in tumor xenografts via shift of mean fluorescence lifetimes of a caspase-3 sensor. We used the genetically encoded sensor TR23K based on the red fluorescent protein TagRFP and chromoprotein KFP linked by 23 amino acid residues (TagRFP-23-KFP) containing a specific caspase cleavage DEVD motif to monitor the activity of caspase-3 in tumor xenografts by means of fluorescence lifetime imaging-Forster resonance energy transfer. Apoptosis was induced by injection of paclitaxel for A549 lung adenocarcinoma and etoposide and cisplatin for HEp-2 pharynx adenocarcinoma. We observed a shift in lifetime distribution from 1.6 to 1.9 ns to 2.1 to 2.4 ns, which indicated the activation of caspase-3. Even within the same tumor, the lifetime varied presumably due to the tumor heterogeneity and the different depth of tumor invasion. Thus, processing time-resolved fluorescence images allows detection of both the cleaved and noncleaved states of the TR23K sensor in real-time mode during the course of several weeks noninvasively. This approach can be used in drug screening, facilitating the development of new anticancer agents as well as improvement of chemotherapy efficiency and its adaptation for personal treatment.
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Affiliation(s)
- Victoria Zherdeva
- Research Center of Biotechnology of the Russian Academy of Sciences, Bach Institute of Biochemistry,, Russia
| | - Natalia I Kazachkina
- Research Center of Biotechnology of the Russian Academy of Sciences, Bach Institute of Biochemistry,, Russia
| | | | - Alexander P Savitsky
- Research Center of Biotechnology of the Russian Academy of Sciences, Bach Institute of Biochemistry,, Russia
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17
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Nobis M, Herrmann D, Warren SC, Kadir S, Leung W, Killen M, Magenau A, Stevenson D, Lucas MC, Reischmann N, Vennin C, Conway JRW, Boulghourjian A, Zaratzian A, Law AM, Gallego-Ortega D, Ormandy CJ, Walters SN, Grey ST, Bailey J, Chtanova T, Quinn JMW, Baldock PA, Croucher PI, Schwarz JP, Mrowinska A, Zhang L, Herzog H, Masedunskas A, Hardeman EC, Gunning PW, Del Monte-Nieto G, Harvey RP, Samuel MS, Pajic M, McGhee EJ, Johnsson AKE, Sansom OJ, Welch HCE, Morton JP, Strathdee D, Anderson KI, Timpson P. A RhoA-FRET Biosensor Mouse for Intravital Imaging in Normal Tissue Homeostasis and Disease Contexts. Cell Rep 2017; 21:274-288. [PMID: 28978480 DOI: 10.1016/j.celrep.2017.09.022] [Citation(s) in RCA: 72] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Revised: 07/06/2017] [Accepted: 09/05/2017] [Indexed: 01/04/2023] Open
Abstract
The small GTPase RhoA is involved in a variety of fundamental processes in normal tissue. Spatiotemporal control of RhoA is thought to govern mechanosensing, growth, and motility of cells, while its deregulation is associated with disease development. Here, we describe the generation of a RhoA-fluorescence resonance energy transfer (FRET) biosensor mouse and its utility for monitoring real-time activity of RhoA in a variety of native tissues in vivo. We assess changes in RhoA activity during mechanosensing of osteocytes within the bone and during neutrophil migration. We also demonstrate spatiotemporal order of RhoA activity within crypt cells of the small intestine and during different stages of mammary gestation. Subsequently, we reveal co-option of RhoA activity in both invasive breast and pancreatic cancers, and we assess drug targeting in these disease settings, illustrating the potential for utilizing this mouse to study RhoA activity in vivo in real time.
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MESH Headings
- Animals
- Antineoplastic Agents/pharmacology
- Biosensing Techniques
- Bone and Bones/cytology
- Bone and Bones/metabolism
- Cell Movement/drug effects
- Dasatinib/pharmacology
- Erlotinib Hydrochloride/pharmacology
- Female
- Fluorescence Resonance Energy Transfer/instrumentation
- Fluorescence Resonance Energy Transfer/methods
- Gene Expression Regulation
- Intestine, Small/metabolism
- Intestine, Small/ultrastructure
- Intravital Microscopy/instrumentation
- Intravital Microscopy/methods
- Mammary Glands, Animal/blood supply
- Mammary Glands, Animal/drug effects
- Mammary Glands, Animal/ultrastructure
- Mammary Neoplasms, Experimental/blood supply
- Mammary Neoplasms, Experimental/drug therapy
- Mammary Neoplasms, Experimental/genetics
- Mammary Neoplasms, Experimental/ultrastructure
- Mechanotransduction, Cellular
- Mice
- Mice, Transgenic
- Neutrophils/metabolism
- Neutrophils/ultrastructure
- Osteocytes/metabolism
- Osteocytes/ultrastructure
- Pancreatic Neoplasms/blood supply
- Pancreatic Neoplasms/drug therapy
- Pancreatic Neoplasms/genetics
- Pancreatic Neoplasms/ultrastructure
- Time-Lapse Imaging/instrumentation
- Time-Lapse Imaging/methods
- rho GTP-Binding Proteins/genetics
- rho GTP-Binding Proteins/metabolism
- rhoA GTP-Binding Protein
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Affiliation(s)
- Max Nobis
- The Garvan Institute of Medical Research, St. Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Sydney, NSW 2010, Australia
| | - David Herrmann
- The Garvan Institute of Medical Research, St. Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Sydney, NSW 2010, Australia
| | - Sean C Warren
- The Garvan Institute of Medical Research, St. Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Sydney, NSW 2010, Australia
| | - Shereen Kadir
- Cancer Research UK Beatson Institute, Switchback Road, Bearsden, Glasgow G611BD, UK
| | - Wilfred Leung
- The Garvan Institute of Medical Research, St. Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Sydney, NSW 2010, Australia
| | - Monica Killen
- The Garvan Institute of Medical Research, St. Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Sydney, NSW 2010, Australia
| | - Astrid Magenau
- The Garvan Institute of Medical Research, St. Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Sydney, NSW 2010, Australia
| | - David Stevenson
- Cancer Research UK Beatson Institute, Switchback Road, Bearsden, Glasgow G611BD, UK
| | - Morghan C Lucas
- The Garvan Institute of Medical Research, St. Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Sydney, NSW 2010, Australia
| | - Nadine Reischmann
- The Garvan Institute of Medical Research, St. Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Sydney, NSW 2010, Australia
| | - Claire Vennin
- The Garvan Institute of Medical Research, St. Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Sydney, NSW 2010, Australia
| | - James R W Conway
- The Garvan Institute of Medical Research, St. Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Sydney, NSW 2010, Australia
| | - Alice Boulghourjian
- The Garvan Institute of Medical Research, St. Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Sydney, NSW 2010, Australia
| | - Anaiis Zaratzian
- The Garvan Institute of Medical Research, St. Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Sydney, NSW 2010, Australia
| | - Andrew M Law
- The Garvan Institute of Medical Research, St. Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Sydney, NSW 2010, Australia
| | - David Gallego-Ortega
- The Garvan Institute of Medical Research, St. Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Sydney, NSW 2010, Australia
| | - Christopher J Ormandy
- The Garvan Institute of Medical Research, St. Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Sydney, NSW 2010, Australia
| | - Stacey N Walters
- The Garvan Institute of Medical Research, St. Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Sydney, NSW 2010, Australia
| | - Shane T Grey
- The Garvan Institute of Medical Research, St. Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Sydney, NSW 2010, Australia
| | - Jacqueline Bailey
- The Garvan Institute of Medical Research, St. Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Sydney, NSW 2010, Australia
| | - Tatyana Chtanova
- The Garvan Institute of Medical Research, St. Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Sydney, NSW 2010, Australia
| | - Julian M W Quinn
- The Garvan Institute of Medical Research, St. Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Sydney, NSW 2010, Australia
| | - Paul A Baldock
- The Garvan Institute of Medical Research, St. Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Sydney, NSW 2010, Australia
| | - Peter I Croucher
- The Garvan Institute of Medical Research, St. Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Sydney, NSW 2010, Australia
| | - Juliane P Schwarz
- Cancer Research UK Beatson Institute, Switchback Road, Bearsden, Glasgow G611BD, UK
| | - Agata Mrowinska
- Cancer Research UK Beatson Institute, Switchback Road, Bearsden, Glasgow G611BD, UK
| | - Lei Zhang
- The Garvan Institute of Medical Research, St. Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Sydney, NSW 2010, Australia
| | - Herbert Herzog
- The Garvan Institute of Medical Research, St. Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Sydney, NSW 2010, Australia
| | - Andrius Masedunskas
- Neuromuscular and Regenerative Medicine Unit, University of New South Wales, Sydney, NSW 2010, Australia; Oncology Research Unit, School of Medical Sciences, University of New South Wales, Sydney, NSW 2010, Australia
| | - Edna C Hardeman
- Neuromuscular and Regenerative Medicine Unit, University of New South Wales, Sydney, NSW 2010, Australia
| | - Peter W Gunning
- Oncology Research Unit, School of Medical Sciences, University of New South Wales, Sydney, NSW 2010, Australia
| | - Gonzalo Del Monte-Nieto
- Developmental and Stem Cell Biology Division, Victor Chang Cardiac Research Institute, Sydney, NSW 2010, Australia; St. Vincent's Clinical School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW 2052, Australia
| | - Richard P Harvey
- Developmental and Stem Cell Biology Division, Victor Chang Cardiac Research Institute, Sydney, NSW 2010, Australia; St. Vincent's Clinical School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW 2052, Australia
| | - Michael S Samuel
- Centre for Cancer Biology, SA Pathology and University of South Australia School of Medicine, University of Adelaide, Adelaide, SA 5000, Australia
| | - Marina Pajic
- The Garvan Institute of Medical Research, St. Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Sydney, NSW 2010, Australia
| | - Ewan J McGhee
- Cancer Research UK Beatson Institute, Switchback Road, Bearsden, Glasgow G611BD, UK
| | | | - Owen J Sansom
- Cancer Research UK Beatson Institute, Switchback Road, Bearsden, Glasgow G611BD, UK
| | - Heidi C E Welch
- Signalling Programme, Babraham Institute, Cambridge CB223AT, UK
| | - Jennifer P Morton
- Cancer Research UK Beatson Institute, Switchback Road, Bearsden, Glasgow G611BD, UK
| | - Douglas Strathdee
- Cancer Research UK Beatson Institute, Switchback Road, Bearsden, Glasgow G611BD, UK
| | | | - Paul Timpson
- The Garvan Institute of Medical Research, St. Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Sydney, NSW 2010, Australia.
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18
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Hsu K, Lee TY, Periasamy A, Kao FJ, Li LT, Lin CY, Lin HJ, Lin M. Adaptable interaction between aquaporin-1 and band 3 reveals a potential role of water channel in blood CO 2 transport. FASEB J 2017; 31:4256-4264. [PMID: 28596233 DOI: 10.1096/fj.201601282r] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2016] [Accepted: 05/22/2017] [Indexed: 12/22/2022]
Abstract
Human CO2 respiration requires rapid conversion between CO2 and HCO3- Carbonic anhydrase II facilitates this reversible reaction inside red blood cells, and band 3 [anion exchanger 1 (AE1)] provides a passage for HCO3- flux across the cell membrane. These 2 proteins are core components of the CO2 transport metabolon. Intracellular H2O is necessary for CO2/HCO3- conversion. However, abundantly expressed aquaporin 1 (AQP1) in erythrocytes is thought not to be part of band 3 complexes or the CO2 transport metabolon. To solve this conundrum, we used Förster resonance energy transfer (FRET) measured by fluorescence lifetime imaging (FLIM-FRET) and identified interaction between aquaporin-1 and band 3 at a distance of 8 nm, within the range of dipole-dipole interaction. Notably, their interaction was adaptable to membrane tonicity changes. This suggests that the function of AQP1 in tonicity response could be coupled or correlated to its function in band 3-mediated CO2/HCO3- exchange. By demonstrating AQP1 as a mobile component of the CO2 transport metabolon, our results uncover a potential role of water channel in blood CO2 transport and respiration.-Hsu, K., Lee, T.-Y., Periasamy, A., Kao, F.-J., Li, L.-T., Lin, C.-Y., Lin, H.-J., Lin, M. Adaptable interaction between aquaporin-1 and band 3 reveals a potential role of water channel in blood CO2 transport.
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Affiliation(s)
- Kate Hsu
- Transfusion Medicine Laboratory, Mackay Memorial Hospital, Tamsui, Taiwan;
| | - Ting-Ying Lee
- Transfusion Medicine Laboratory, Mackay Memorial Hospital, Tamsui, Taiwan
| | - Ammasi Periasamy
- W. M. Keck Center for Cellular Imaging, University of Virginia, Charlottesville, Virginia, USA
| | - Fu-Jen Kao
- Institute of Biophotonics, National Yang-Ming University, Taipei, Taiwan
| | - Li-Tzu Li
- Graduate Institute of Medical Sciences, National Defense Medical Center, Taipei, Taiwan
| | - Chuang-Yu Lin
- Center for iPS Cell Research and Application (CiRA), Kyoto University, Kyoto, Japan
| | - Hui-Ju Lin
- Transfusion Medicine Laboratory, Mackay Memorial Hospital, Tamsui, Taiwan
| | - Marie Lin
- Transfusion Medicine Laboratory, Mackay Memorial Hospital, Tamsui, Taiwan
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19
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Conway JRW, Warren SC, Timpson P. Context-dependent intravital imaging of therapeutic response using intramolecular FRET biosensors. Methods 2017; 128:78-94. [PMID: 28435000 DOI: 10.1016/j.ymeth.2017.04.014] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Revised: 03/13/2017] [Accepted: 04/08/2017] [Indexed: 12/18/2022] Open
Abstract
Intravital microscopy represents a more physiologically relevant method for assessing therapeutic response. However, the movement into an in vivo setting brings with it several additional considerations, the primary being the context in which drug activity is assessed. Microenvironmental factors, such as hypoxia, pH, fibrosis, immune infiltration and stromal interactions have all been shown to have pronounced effects on drug activity in a more complex setting, which is often lost in simpler two- or three-dimensional assays. Here we present a practical guide for the application of intravital microscopy, looking at the available fluorescent reporters and their respective expression systems and analysis considerations. Moving in vivo, we also discuss the microscopy set up and methods available for overlaying microenvironmental context to the experimental readouts. This enables a smooth transition into applying higher fidelity intravital imaging to improve the drug discovery process.
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Affiliation(s)
- James R W Conway
- Garvan Institute of Medical Research and The Kinghorn Cancer Centre, Cancer Division, Sydney, NSW 2010, Australia; St Vincent's Clinical School, Faculty of Medicine, University of NSW, Sydney, NSW 2010, Australia
| | - Sean C Warren
- Garvan Institute of Medical Research and The Kinghorn Cancer Centre, Cancer Division, Sydney, NSW 2010, Australia; St Vincent's Clinical School, Faculty of Medicine, University of NSW, Sydney, NSW 2010, Australia
| | - Paul Timpson
- Garvan Institute of Medical Research and The Kinghorn Cancer Centre, Cancer Division, Sydney, NSW 2010, Australia; St Vincent's Clinical School, Faculty of Medicine, University of NSW, Sydney, NSW 2010, Australia.
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20
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Weitsman G, Barber PR, Nguyen LK, Lawler K, Patel G, Woodman N, Kelleher MT, Pinder SE, Rowley M, Ellis PA, Purushotham AD, Coolen AC, Kholodenko BN, Vojnovic B, Gillett C, Ng T. HER2-HER3 dimer quantification by FLIM-FRET predicts breast cancer metastatic relapse independently of HER2 IHC status. Oncotarget 2016; 7:51012-51026. [PMID: 27618787 PMCID: PMC5239455 DOI: 10.18632/oncotarget.9963] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Accepted: 05/23/2016] [Indexed: 01/08/2023] Open
Abstract
Overexpression of HER2 is an important prognostic marker, and the only predictive biomarker of response to HER2-targeted therapies in invasive breast cancer. HER2-HER3 dimer has been shown to drive proliferation and tumor progression, and targeting of this dimer with pertuzumab alongside chemotherapy and trastuzumab, has shown significant clinical utility. The purpose of this study was to accurately quantify HER2-HER3 dimerisation in formalin fixed paraffin embedded (FFPE) breast cancer tissue as a novel prognostic biomarker.FFPE tissues were obtained from patients included in the METABRIC (Molecular Taxonomy of Breast Cancer International Consortium) study. HER2-HER3 dimerisation was quantified using an improved fluorescence lifetime imaging microscopy (FLIM) histology-based analysis. Analysis of 131 tissue microarray cores demonstrated that the extent of HER2-HER3 dimer formation as measured by Förster Resonance Energy Transfer (FRET) determined through FLIM predicts the likelihood of metastatic relapse up to 10 years after surgery (hazard ratio 3.91 (1.61-9.5), p = 0.003) independently of HER2 expression, in a multivariate model. Interestingly there was no correlation between the level of HER2 protein expressed and HER2-HER3 heterodimer formation. We used a mathematical model that takes into account the complex interactions in a network of all four HER proteins to explain this counterintuitive finding.Future utility of this technique may highlight a group of patients who do not overexpress HER2 protein but are nevertheless dependent on the HER2-HER3 heterodimer as driver of proliferation. This assay could, if validated in a group of patients treated with, for instance pertuzumab, be used as a predictive biomarker to predict for response to such targeted therapies.
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Affiliation(s)
- Gregory Weitsman
- Richard Dimbleby Department of Cancer Research, Randall Division and Division of Cancer Studies, King's College London, Guy's Medical School Campus, London, UK
| | - Paul R. Barber
- Department of Oncology, Cancer Research UK and Medical Research Council Oxford Institute for Radiation Oncology, University of Oxford, Oxford, UK
- Institute for Mathematical and Molecular Biomedicine, King's College London, Guy's Medical School Campus, London, UK
| | - Lan K. Nguyen
- Systems Biology Ireland, University College Dublin, Belfield, Dublin, Ireland
- Department of Biochemistry and Molecular Biology, School of Biomedical Sciences and Biomedical Discovery Institute, Monash University, Melbourne, Australia
| | - Katherine Lawler
- Institute for Mathematical and Molecular Biomedicine, King's College London, Guy's Medical School Campus, London, UK
| | - Gargi Patel
- Richard Dimbleby Department of Cancer Research, Randall Division and Division of Cancer Studies, King's College London, Guy's Medical School Campus, London, UK
- Sussex Cancer Centre, Brighton and Sussex University Hospitals, Royal Sussex County Hospital, Brighton, UK
| | - Natalie Woodman
- Research Oncology, Division of Cancer Studies, King's College London, Guy's Hospital, Great Maze Pond, London, UK
- Breakthrough Breast Cancer Research Unit, Department of Research Oncology, Guy's Hospital King's College London School of Medicine, London, UK
| | - Muireann T. Kelleher
- Department of Medical Oncology, St George's Hospital NHS Foundation Trust, London, UK
| | - Sarah E. Pinder
- Research Oncology, Division of Cancer Studies, King's College London, Guy's Hospital, Great Maze Pond, London, UK
- Breakthrough Breast Cancer Research Unit, Department of Research Oncology, Guy's Hospital King's College London School of Medicine, London, UK
| | - Mark Rowley
- Institute for Mathematical and Molecular Biomedicine, King's College London, Guy's Medical School Campus, London, UK
| | - Paul A. Ellis
- Research Oncology, Division of Cancer Studies, King's College London, Guy's Hospital, Great Maze Pond, London, UK
| | - Anand D. Purushotham
- Research Oncology, Division of Cancer Studies, King's College London, Guy's Hospital, Great Maze Pond, London, UK
| | - Anthonius C. Coolen
- Institute for Mathematical and Molecular Biomedicine, King's College London, Guy's Medical School Campus, London, UK
| | - Boris N. Kholodenko
- Systems Biology Ireland, University College Dublin, Belfield, Dublin, Ireland
| | - Borivoj Vojnovic
- Richard Dimbleby Department of Cancer Research, Randall Division and Division of Cancer Studies, King's College London, Guy's Medical School Campus, London, UK
- Department of Oncology, Cancer Research UK and Medical Research Council Oxford Institute for Radiation Oncology, University of Oxford, Oxford, UK
| | - Cheryl Gillett
- Research Oncology, Division of Cancer Studies, King's College London, Guy's Hospital, Great Maze Pond, London, UK
| | - Tony Ng
- Richard Dimbleby Department of Cancer Research, Randall Division and Division of Cancer Studies, King's College London, Guy's Medical School Campus, London, UK
- Breakthrough Breast Cancer Research Unit, Department of Research Oncology, Guy's Hospital King's College London School of Medicine, London, UK
- UCL Cancer Institute, Paul O'Gorman Building, University College London, London, UK
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Abstract
Septins are highly conserved cytoskeletal proteins involved in a variety of biological processes such as cell polarization and cytokinesis. In humans, functional defects in these proteins have been linked to cancer and neuronal diseases. In recent years, substantial progress has been made in studying the structure of septin subunits and the formation of defined heteromeric building blocks. These are assembled into higher-order structures at distinct subcellular sites. An important microscopic approach in studying septin assembly and dynamics is the use of septins tagged with fluorescent proteins. This revealed, eg, that septins form rings during cytokinesis and that septins build extended filaments partially colocalizing with actin cables and microtubules. Here, we describe extensive live cell imaging of septins in the model microorganism Ustilago maydis. We present techniques to study dynamic localization of protein and septin mRNA on shuttling endosomes as well as colocalization of proteins at these highly motile units. Moreover, FLIM-FRET experiments for analyzing local protein interactions are presented. Importantly, these imaging approaches transfer well to other fungal and animal model systems for in vivo analysis of septin dynamics.
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Abstract
Kinetochores play essential roles in coordinating mitosis, as a mechanical connector between chromosome and microtubule and as a source of numerous biochemical signals. These mechanical and biochemical behaviors of kinetochores change dynamically in cells during mitosis. Therefore, understanding kinetochore function requires an imaging tool that quantifies the protein-protein interactions or biochemical changes with high spatiotemporal resolution. FRET has previously been used in combination with biosensors to probe protein-protein interactions and biochemical activity. In this chapter, we introduce FLIM-FRET, a lifetime-based method that quantifies FRET, and describe the use of FLIM-FRET as a method for studying dynamic kinetochore behavior in cells with high spatiotemporal resolution.
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Affiliation(s)
- Tae Yeon Yoo
- School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
| | - Daniel J Needleman
- School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA.
- Departments of Applied Physics, and Molecular and Cellular Biology, Harvard University, 365.1 Northwest Building, 52 Oxford St., Cambridge, MA, 02138, USA.
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23
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Abstract
DNA methylation 5-methylcytosine (5mC) predicts a compacting chromatin inaccessible to transcription. The discovery of 5-hydroxymethylcytosine (5hmC), which is derived from 5mC, adds a new dimension to the mechanism and role of DNA methylation in epigenetics. Genomic evidence indicates that the 5hmC is located in the alternate regions to 5mC. However, the nature of 5hmC, as compared with classical 5mC remains unclear. Observing the mouse brain through embryonic development to the adult, first, we found that 5hmC is not merely an intermediate metabolite of demethylation, but is long lasting, chromatically distinct, and dynamically changing during neurodevelopment. Second, we found that 5hmC distinctly differs from 5mC in its chromatin affiliation during neural stem cell (NSC) development. Thirdly, we found both 5mC and 5hmC to be uniquely polarized and dynamic through the NSC development. 5mC was found to progressively polarize with MBD1 and MeCP2, and recruits H3K9me3 and H3K27me3; while 5hmC progressively co-localizes with MBD3 and recruits H3K4me2. Critical differential binding of 5mC with MBD1, and 5hmC with MBD3 was validated by Resonance Energy Transfer technique FLIM-FRET. This transition and polarization coincides with neuroprogenitor differentiation. Finally, at the time of synaptogenesis, 5mC gradually accumulates in the heterochromatin while 5hmC accumulates in the euchromatin, which is consistent with the co-localization of 5hmC with PolII, which mediates RNA transcription. Our data indicate that 5mC and 5hmC are diverse in their functional interactions with chromatin. This diversity is likely to contribute to the versatile epigenetic control of transcription mediating brain development and functional maintenance of adult brain.
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Affiliation(s)
- Yuanyuan Chen
- Department of Anatomy and Cell Biology, Indiana University School of Medicine Indianapolis, IN, USA
| | - Nur P Damayanti
- Agricultural and Biological Engineering, Bindley Bioscience Center, Purdue University West Lafayette, IN, USA
| | - Joseph Irudayaraj
- Agricultural and Biological Engineering, Bindley Bioscience Center, Purdue University West Lafayette, IN, USA
| | - Kenneth Dunn
- Division of Nephology, Department of Medicine, Indiana University School of Medicine Indianapolis, IN, USA
| | - Feng C Zhou
- Department of Anatomy and Cell Biology, Indiana University School of Medicine Indianapolis, IN, USA ; Stark Neuroscience Research Institute, Indiana University School of Medicine Indianapolis, IN, USA
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Hoffmann C, Moes D, Dieterle M, Neumann K, Moreau F, Tavares Furtado A, Dumas D, Steinmetz A, Thomas C. Live cell imaging reveals actin-cytoskeleton-induced self-association of the actin-bundling protein WLIM1. J Cell Sci 2014; 127:583-98. [PMID: 24284066 DOI: 10.1242/jcs.134536] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Crosslinking of actin filaments into bundles is essential for the assembly and stabilization of specific cytoskeletal structures. However, relatively little is known about the molecular mechanisms underlying actin bundle formation. The two LIM-domain-containing proteins define a novel and evolutionarily conserved family of actin-bundling proteins whose actin-binding and -crosslinking activities primarily rely on their LIM domains. Using TIRF microscopy, we describe real-time formation of actin bundles induced by tobacco NtWLIM1 in vitro. We show that NtWLIM1 binds to single filaments and subsequently promotes their interaction and zippering into tight bundles of mixed polarity. NtWLIM1-induced bundles grew by both elongation of internal filaments and addition of preformed fragments at their extremities. Importantly, these data are highly consistent with the modes of bundle formation and growth observed in transgenic Arabidopsis plants expressing a GFP-fused Arabidopsis AtWLIM1 protein. Using two complementary live cell imaging approaches, a close relationship between NtWLIM1 subcellular localization and self-association was established. Indeed, both BiFC and FLIM-FRET data revealed that, although unstable NtWLIM1 complexes can sporadically form in the cytosol, stable complexes concentrate along the actin cytoskeleton. Remarkably, disruption of the actin cytoskeleton significantly impaired self-association of NtWLIM1. In addition, biochemical analyses support the idea that F-actin facilitates the switch of purified recombinant NtWLIM1 from a monomeric to a di- or oligomeric state. On the basis of our data, we propose a model in which actin binding promotes the formation and stabilization of NtWLIM1 complexes, which in turn might drive the crosslinking of actin filaments.
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Affiliation(s)
- Céline Hoffmann
- Centre de Recherche Public-Santé, 84 Val Fleuri, L-1526 Luxembourg, Luxembourg
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Caron NS, Desmond CR, Xia J, Truant R. Polyglutamine domain flexibility mediates the proximity between flanking sequences in huntingtin. Proc Natl Acad Sci U S A 2013; 110:14610-5. [PMID: 23898200 DOI: 10.1073/pnas.1301342110] [Citation(s) in RCA: 110] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Huntington disease (HD) is a neurodegenerative disorder caused by a CAG expansion within the huntingtin gene that encodes a polymorphic glutamine tract at the amino terminus of the huntingtin protein. HD is one of nine polyglutamine expansion diseases. The clinical threshold of polyglutamine expansion for HD is near 37 repeats, but the mechanism of this pathogenic length is poorly understood. Using Förster resonance energy transfer, we describe an intramolecular proximity between the N17 domain and the downstream polyproline region that flanks the polyglutamine tract of huntingtin. Our data support the hypothesis that the polyglutamine tract can act as a flexible domain, allowing the flanking domains to come into close spatial proximity. This flexibility is impaired with expanded polyglutamine tracts, and we can detect changes in huntingtin conformation at the pathogenic threshold for HD. Altering the structure of N17, either via phosphomimicry or with small molecules, also affects the proximity between the flanking domains. The structural capacity of N17 to fold back toward distal regions within huntingtin requires an interacting protein, protein kinase C and casein kinase 2 substrate in neurons 1 (PACSIN1). This protein has the ability to bind both N17 and the polyproline region, stabilizing the interaction between these two domains. We also developed an antibody-based FRET assay that can detect conformational changes within endogenous huntingtin in wild-type versus HD fibroblasts. Therefore, we hypothesize that wild-type length polyglutamine tracts within huntingtin can form a flexible domain that is essential for proper functional intramolecular proximity, conformations, and dynamics.
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Sun Y, Rombola C, Jyothikumar V, Periasamy A. Förster resonance energy transfer microscopy and spectroscopy for localizing protein-protein interactions in living cells. Cytometry A 2013; 83:780-93. [PMID: 23813736 DOI: 10.1002/cyto.a.22321] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2012] [Revised: 04/08/2013] [Accepted: 05/23/2013] [Indexed: 12/15/2022]
Abstract
The fundamental theory of Förster resonance energy transfer (FRET) was established in the 1940s. Its great power was only realized in the past 20 years after different techniques were developed and applied to biological experiments. This success was made possible by the availability of suitable fluorescent probes, advanced optics, detectors, microscopy instrumentation, and analytical tools. Combined with state-of-the-art microscopy and spectroscopy, FRET imaging allows scientists to study a variety of phenomena that produce changes in molecular proximity, thereby leading to many significant findings in the life sciences. In this review, we outline various FRET imaging techniques and their strengths and limitations; we also provide a biological model to demonstrate how to investigate protein-protein interactions in living cells using both intensity- and fluorescence lifetime-based FRET microscopy methods.
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Affiliation(s)
- Yuansheng Sun
- The W.M. Keck Center for Cellular Imaging (KCCI), Department of Biology, Physical and Life Sciences Building, University of Virginia, Charlottesville, Virginia
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