1
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Beyer JN, Serebrenik YV, Toy K, Najar MA, Raniszewski NR, Shalem O, Burslem GM. Intracellular Protein Editing to Enable Incorporation of Non-Canonical Residues into Endogenous Proteins. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.07.08.602493. [PMID: 39026884 PMCID: PMC11257474 DOI: 10.1101/2024.07.08.602493] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/20/2024]
Abstract
The ability to study proteins in a cellular context is crucial to our understanding of biology. Here, we report a new technology for "intracellular protein editing", drawing from intein- mediated protein splicing, genetic code expansion, and endogenous protein tagging. This protein editing approach enables us to rapidly and site specifically install residues and chemical handles into a protein of interest. We demonstrate the power of this protein editing platform to edit cellular proteins, inserting epitope peptides, protein-specific sequences, and non-canonical amino acids (ncAAs). Importantly, we employ an endogenous tagging approach to apply our protein editing technology to endogenous proteins with minimal perturbation. We anticipate that the protein editing technology presented here will be applied to a diverse set of problems, enabling novel experiments in live mammalian cells and therefore provide unique biological insights.
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2
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Bogdanova YA, Solovyev ID, Baleeva NS, Myasnyanko IN, Gorshkova AA, Gorbachev DA, Gilvanov AR, Goncharuk SA, Goncharuk MV, Mineev KS, Arseniev AS, Bogdanov AM, Savitsky AP, Baranov MS. Fluorescence lifetime multiplexing with fluorogen activating protein FAST variants. Commun Biol 2024; 7:799. [PMID: 38956304 PMCID: PMC11219735 DOI: 10.1038/s42003-024-06501-1] [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: 08/28/2023] [Accepted: 06/24/2024] [Indexed: 07/04/2024] Open
Abstract
In this paper, we propose a fluorescence-lifetime imaging microscopy (FLIM) multiplexing system based on the fluorogen-activating protein FAST. This genetically encoded fluorescent labeling platform employs FAST mutants that activate the same fluorogen but provide different fluorescence lifetimes for each specific protein-dye pair. All the proposed probes with varying lifetimes possess nearly identical and the smallest-in-class size, along with quite similar steady-state optical properties. In live mammalian cells, we target these chemogenetic tags to two intracellular structures simultaneously, where their fluorescence signals are clearly distinguished by FLIM. Due to the unique structure of certain fluorogens under study, their complexes with FAST mutants display a monophasic fluorescence decay, which may facilitate enhanced multiplexing efficiency by reducing signal cross-talks and providing optimal prerequisites for signal separation upon co-localized and/or spatially overlapped labeling.
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Affiliation(s)
- Yulia A Bogdanova
- Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya 16/10, 117997, Moscow, Russia
| | - Ilya D Solovyev
- A.N. Bach Institute of Biochemistry, Research Center of Biotechnology of the Russian Academy of Sciences, 119071, Moscow, Russia
| | - Nadezhda S Baleeva
- Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya 16/10, 117997, Moscow, Russia
- Pirogov Russian National Research Medical University, Ostrovitianov 1, Moscow, 117997, Russia
| | - Ivan N Myasnyanko
- Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya 16/10, 117997, Moscow, Russia
- Pirogov Russian National Research Medical University, Ostrovitianov 1, Moscow, 117997, Russia
| | - Anastasia A Gorshkova
- Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya 16/10, 117997, Moscow, Russia
| | - Dmitriy A Gorbachev
- Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya 16/10, 117997, Moscow, Russia
| | - Aidar R Gilvanov
- Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya 16/10, 117997, Moscow, Russia
| | - Sergey A Goncharuk
- Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya 16/10, 117997, Moscow, Russia
| | - Marina V Goncharuk
- Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya 16/10, 117997, Moscow, Russia
| | - Konstantin S Mineev
- Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya 16/10, 117997, Moscow, Russia
- Goethe University Frankfurt, Frankfurt am Main, 60433, Germany
| | - Alexander S Arseniev
- Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya 16/10, 117997, Moscow, Russia
| | - Alexey M Bogdanov
- Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya 16/10, 117997, Moscow, Russia
- Department of Photonics, İzmir Institute of Technology, 35430, İzmir, Turkey
| | - Alexander P Savitsky
- A.N. Bach Institute of Biochemistry, Research Center of Biotechnology of the Russian Academy of Sciences, 119071, Moscow, Russia
| | - Mikhail S Baranov
- Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya 16/10, 117997, Moscow, Russia.
- Pirogov Russian National Research Medical University, Ostrovitianov 1, Moscow, 117997, Russia.
- Department of Biology, Lomonosov Moscow State University, Moscow, 119991 Russia, 121205, Moscow, Russia.
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3
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Baleeva NS, Bogdanova YA, Goncharuk MV, Sokolov AI, Myasnyanko IN, Kublitski VS, Smirnov AY, Gilvanov AR, Goncharuk SA, Mineev KS, Baranov MS. A Combination of Library Screening and Rational Mutagenesis Expands the Available Color Palette of the Smallest Fluorogen-Activating Protein Tag nanoFAST. Int J Mol Sci 2024; 25:3054. [PMID: 38474299 DOI: 10.3390/ijms25053054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2024] [Revised: 03/01/2024] [Accepted: 03/04/2024] [Indexed: 03/14/2024] Open
Abstract
NanoFAST is the smallest fluorogen-activating protein, consisting of only 98 amino acids, used as a genetically encoded fluorescent tag. Previously, only a single fluorogen with an orange color was revealed for this protein. In the present paper, using rational mutagenesis and in vitro screening of fluorogens libraries, we expanded the color palette of this tag. We discovered that E46Q is one of the key substitutions enabling the range of possible fluorogens to be expanded. The introduction of this and several other substitutions has made it possible to use not only orange but also red and green fluorogens with the modified protein.
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Affiliation(s)
- Nadezhda S Baleeva
- Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya 16/10, 117997 Moscow, Russia
- Laboratory of Medicinal Substances Chemistry, Institute of Translational Medicine, Pirogov Russian National Research Medical University, Ostrovitianov 1, 117997 Moscow, Russia
| | - Yulia A Bogdanova
- Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya 16/10, 117997 Moscow, Russia
| | - Marina V Goncharuk
- Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya 16/10, 117997 Moscow, Russia
| | - Anatolii I Sokolov
- Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya 16/10, 117997 Moscow, Russia
- Laboratory of Medicinal Substances Chemistry, Institute of Translational Medicine, Pirogov Russian National Research Medical University, Ostrovitianov 1, 117997 Moscow, Russia
| | - Ivan N Myasnyanko
- Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya 16/10, 117997 Moscow, Russia
- Laboratory of Medicinal Substances Chemistry, Institute of Translational Medicine, Pirogov Russian National Research Medical University, Ostrovitianov 1, 117997 Moscow, Russia
| | - Vadim S Kublitski
- Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya 16/10, 117997 Moscow, Russia
| | - Alexander Yu Smirnov
- Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya 16/10, 117997 Moscow, Russia
- Laboratory of Medicinal Substances Chemistry, Institute of Translational Medicine, Pirogov Russian National Research Medical University, Ostrovitianov 1, 117997 Moscow, Russia
| | - Aidar R Gilvanov
- Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya 16/10, 117997 Moscow, Russia
| | - Sergey A Goncharuk
- Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya 16/10, 117997 Moscow, Russia
| | - Konstantin S Mineev
- Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya 16/10, 117997 Moscow, Russia
| | - Mikhail S Baranov
- Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya 16/10, 117997 Moscow, Russia
- Laboratory of Medicinal Substances Chemistry, Institute of Translational Medicine, Pirogov Russian National Research Medical University, Ostrovitianov 1, 117997 Moscow, Russia
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4
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Gidden Z, Oi C, Johnston EJ, Konieczna Z, Bhaskar H, Mendive-Tapia L, de Moliner F, Rosser SJ, Mochrie SGJ, Vendrell M, Horrocks MH, Regan L. Imaging Proteins Sensitive to Direct Fusions Using Transient Peptide-Peptide Interactions. NANO LETTERS 2023; 23:10633-10641. [PMID: 37916770 PMCID: PMC10683072 DOI: 10.1021/acs.nanolett.3c03780] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Revised: 10/30/2023] [Accepted: 10/30/2023] [Indexed: 11/03/2023]
Abstract
Fluorescence microscopy enables specific visualization of proteins in living cells and has played an important role in our understanding of the protein subcellular location and function. Some proteins, however, show altered localization or function when labeled using direct fusions to fluorescent proteins, making them difficult to study in live cells. Additionally, the resolution of fluorescence microscopy is limited to ∼200 nm, which is 2 orders of magnitude larger than the size of most proteins. To circumvent these challenges, we previously developed LIVE-PAINT, a live-cell super-resolution approach that takes advantage of short interacting peptides to transiently bind a fluorescent protein to the protein-of-interest. Here, we successfully use LIVE-PAINT to image yeast membrane proteins that do not tolerate the direct fusion of a fluorescent protein by using peptide tags as short as 5-residues. We also demonstrate that it is possible to resolve multiple proteins at the nanoscale concurrently using orthogonal peptide interaction pairs.
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Affiliation(s)
- Zoe Gidden
- School
of Biological Sciences, University of Edinburgh, Edinburgh, EH9 3DW, U.K.
- EaStCHEM
School of Chemistry, The University of Edinburgh, Edinburgh, EH9 3FJ, U.K.
| | - Curran Oi
- Department
of Genome Sciences, University of Washington, Seattle, Washington 98195, United States
| | - Emily J. Johnston
- School
of Biological Sciences, University of Edinburgh, Edinburgh, EH9 3DW, U.K.
- Centre
for Engineering Biology, University of Edinburgh, Edinburgh EH9 3BF, U.K.
| | - Zuzanna Konieczna
- EaStCHEM
School of Chemistry, The University of Edinburgh, Edinburgh, EH9 3FJ, U.K.
- IRR
Chemistry Hub, Institute for Regeneration and Repair, The University of Edinburgh, Edinburgh, EH16 4UU, U.K.
| | - Haresh Bhaskar
- School
of Biological Sciences, University of Edinburgh, Edinburgh, EH9 3DW, U.K.
- EaStCHEM
School of Chemistry, The University of Edinburgh, Edinburgh, EH9 3FJ, U.K.
- IRR
Chemistry Hub, Institute for Regeneration and Repair, The University of Edinburgh, Edinburgh, EH16 4UU, U.K.
| | - Lorena Mendive-Tapia
- IRR
Chemistry Hub, Institute for Regeneration and Repair, The University of Edinburgh, Edinburgh, EH16 4UU, U.K.
- Centre
for
Inflammation Research, The University of
Edinburgh, Edinburgh, EH16 4UU, U.K.
| | - Fabio de Moliner
- IRR
Chemistry Hub, Institute for Regeneration and Repair, The University of Edinburgh, Edinburgh, EH16 4UU, U.K.
- Centre
for
Inflammation Research, The University of
Edinburgh, Edinburgh, EH16 4UU, U.K.
| | - Susan J. Rosser
- School
of Biological Sciences, University of Edinburgh, Edinburgh, EH9 3DW, U.K.
- Centre
for Engineering Biology, University of Edinburgh, Edinburgh EH9 3BF, U.K.
| | - Simon G. J. Mochrie
- Department
of Physics, Yale University, New Haven, Connecticut 06520, United States
- Integrated
Graduate Program in Physical and Engineering Biology, Yale University, New Haven, Connecticut 06520, United States
| | - Marc Vendrell
- IRR
Chemistry Hub, Institute for Regeneration and Repair, The University of Edinburgh, Edinburgh, EH16 4UU, U.K.
- Centre
for
Inflammation Research, The University of
Edinburgh, Edinburgh, EH16 4UU, U.K.
| | - Mathew H. Horrocks
- EaStCHEM
School of Chemistry, The University of Edinburgh, Edinburgh, EH9 3FJ, U.K.
- IRR
Chemistry Hub, Institute for Regeneration and Repair, The University of Edinburgh, Edinburgh, EH16 4UU, U.K.
| | - Lynne Regan
- School
of Biological Sciences, University of Edinburgh, Edinburgh, EH9 3DW, U.K.
- Centre
for Engineering Biology, University of Edinburgh, Edinburgh EH9 3BF, U.K.
- Integrated
Graduate Program in Physical and Engineering Biology, Yale University, New Haven, Connecticut 06520, United States
- Institute
of Quantitative Biology, Biochemistry and Biotechnology, Edinburgh, EH9 3FF, U.K.
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5
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Mann G, Sadhu P, Brik A. Multiplexed Delivery of Synthetic (Un)Conjugatable Ubiquitin and SUMO2 Enables Simultaneous Monitoring of Their Localization and Function in Live Cells. Chembiochem 2022; 23:e202200122. [PMID: 35235714 PMCID: PMC9401080 DOI: 10.1002/cbic.202200122] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Indexed: 11/17/2022]
Abstract
Ubiquitin (Ub) and its related small Ub like modifier (SUMO) are among the most influential protein post-translational modifications in eukaryotes. Unfortunately, visualizing these modifications in live cells is a challenging task. Chemical protein synthesis offers great opportunities in studying and further understanding Ub and SUMO biology. Nevertheless, the low cell permeability of proteins limits these studies mainly for in vitro applications. Here, we introduce a multiplexed protein cell delivery approach, termed MBL (multiplexed bead loading), for simultaneous loading of up to four differentially labeled proteins with organic fluorophores. We applied MBL to visualize ubiquitination and SUMOylation events in live and untransfected cells without fluorescent protein tags or perturbation to their endogenous levels. Our study reveals unprecedented involvements of Ub and SUMO2 in lysosomes depending on conjugation states. We envision that this approach will improve our understanding of dynamic cellular processes such as formation and disassembly of membraneless organelles.
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Affiliation(s)
- Guy Mann
- Schulich Faculty of ChemistryTechnion-Israel Institute of TechnologyHaifa3200008Israel
| | - Pradeep Sadhu
- Schulich Faculty of ChemistryTechnion-Israel Institute of TechnologyHaifa3200008Israel
| | - Ashraf Brik
- Schulich Faculty of ChemistryTechnion-Israel Institute of TechnologyHaifa3200008Israel
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6
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Fagbadebo FO, Rothbauer U. Peptide-Tag Specific Nanobodies for Studying Proteins in Live Cells. Methods Mol Biol 2022; 2446:555-579. [PMID: 35157294 DOI: 10.1007/978-1-0716-2075-5_29] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Single-domain antibodies such as nanobodies (Nbs) have substantially expanded the possibilities of advanced cellular imaging. In comparison to conventional antibodies, Nbs are characterized by small size, high stability, and solubility in many environments, including the cytoplasm. Nbs can be efficiently functionalized or modified according to the needs of the imaging approach. Target-specific Nbs can be easily converted into genetically encoded fluorescently labeled intrabodies, also known as chromobodies (CBs), which represent powerful tools to study the dynamics of different proteins of interest within living cells. In this context, CBs specific for a short peptide epitope provide a versatile alternative to bypass the limitations observed with larger fluorescent protein fusions and can be readily used to visualize and monitor peptide-tagged proteins for which specific Nbs are not available. Here, we present our novel detection system comprising a 15 amino acid peptide-tag (PepTag) in combination with a peptide-tag specific CB (PepCB). We provide protocols for adding the PepTag to different proteins of interest, reformatting the peptide-specific Nb (PepNb) into a CB for expression in mammalian cells, and establishment of stable cell lines expressing the PepCB for protein interaction assays and compound screenings.
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Affiliation(s)
- Funmilayo O Fagbadebo
- 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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7
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Reddi RN, Rogel A, Resnick E, Gabizon R, Prasad PK, Gurwicz N, Barr H, Shulman Z, London N. Site-Specific Labeling of Endogenous Proteins Using CoLDR Chemistry. J Am Chem Soc 2021; 143:20095-20108. [PMID: 34817989 PMCID: PMC8662641 DOI: 10.1021/jacs.1c06167] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
![]()
Chemical modifications
of native proteins can affect their stability,
activity, interactions, localization, and more. However, there are
few nongenetic methods for the installation of chemical modifications
at a specific protein site in cells. Here we report a covalent ligand
directed release (CoLDR) site-specific labeling strategy, which enables
the installation of a variety of functional tags on a target protein
while releasing the directing ligand. Using this approach, we were
able to label various proteins such as BTK, K-RasG12C,
and SARS-CoV-2 PLpro with different tags. For BTK we have
shown selective labeling in cells of both alkyne and fluorophores
tags. Protein labeling by traditional affinity methods often inhibits
protein activity since the directing ligand permanently occupies the
target binding pocket. We have shown that using CoLDR chemistry, modification
of BTK by these probes in cells preserves its activity. We demonstrated
several applications for this approach including determining the half-life
of BTK in its native environment with minimal perturbation, as well
as quantification of BTK degradation by a noncovalent proteolysis
targeting chimera (PROTAC) by in-gel fluorescence. Using an environment-sensitive
“turn-on” fluorescent probe, we were able to monitor
ligand binding to the active site of BTK. Finally, we have demonstrated
efficient CoLDR-based BTK PROTACs (DC50 < 100 nM), which
installed a CRBN binder onto BTK. This approach joins very few available
labeling strategies that maintain the target protein activity and
thus makes an important addition to the toolbox of chemical biology.
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Affiliation(s)
- Rambabu N Reddi
- Department of Chemical and Structural Biology, The Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - Adi Rogel
- Department of Chemical and Structural Biology, The Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - Efrat Resnick
- Department of Chemical and Structural Biology, The Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - Ronen Gabizon
- Department of Chemical and Structural Biology, The Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - Pragati Kishore Prasad
- Department of Chemical and Structural Biology, The Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - Neta Gurwicz
- Department of Immunology, The Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - Haim Barr
- Wohl Institute for Drug Discovery of the Nancy and Stephen Grand Israel National Center for Personalized Medicine, The Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - Ziv Shulman
- Department of Immunology, The Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - Nir London
- Department of Chemical and Structural Biology, The Weizmann Institute of Science, Rehovot, 7610001, Israel
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8
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Montecinos-Franjola F, Bauer BL, Mears JA, Ramachandran R. GFP fluorescence tagging alters dynamin-related protein 1 oligomerization dynamics and creates disassembly-refractory puncta to mediate mitochondrial fission. Sci Rep 2020; 10:14777. [PMID: 32901052 PMCID: PMC7479153 DOI: 10.1038/s41598-020-71655-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Accepted: 08/19/2020] [Indexed: 01/22/2023] Open
Abstract
Green fluorescent protein (GFP)-tagging is the prevalent strategy to monitor protein dynamics in living cells. However, the consequences of appending the bulky GFP moiety to the protein of interest are rarely investigated. Here, using a powerful combination of quantitative fluorescence spectroscopic and imaging techniques, we have examined the oligomerization dynamics of the GFP-tagged mitochondrial fission GTPase dynamin-related protein 1 (Drp1) both in vitro and in vivo. We find that GFP-tagged Drp1 exhibits impaired oligomerization equilibria in solution that corresponds to a greatly diminished cooperative GTPase activity in comparison to native Drp1. Consequently, GFP-tagged Drp1 constitutes aberrantly stable, GTP-resistant supramolecular assemblies both in vitro and in vivo, neither of which reflects a more dynamic native Drp1 oligomerization state. Indeed, GFP-tagged Drp1 is detected more frequently per unit length over mitochondria in Drp1-null mouse embryonic fibroblasts (MEFs) compared to wild-type (wt) MEFs, indicating that the drastically reduced GTP turnover restricts oligomer disassembly from the mitochondrial surface relative to mixed oligomers comprising native and GFP-tagged Drp1. Yet, GFP-tagged Drp1 retains the capacity to mediate membrane constriction in vitro and mitochondrial division in vivo. These findings suggest that instead of robust assembly-disassembly dynamics, persistent Drp1 higher-order oligomerization over membranes is sufficient for mitochondrial fission.
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Affiliation(s)
- Felipe Montecinos-Franjola
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
| | - Brianna L Bauer
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
| | - Jason A Mears
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA.,Center for Mitochondrial Diseases, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA.,Cleveland Center for Membrane and Structural Biology, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
| | - Rajesh Ramachandran
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA. .,Cleveland Center for Membrane and Structural Biology, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA.
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9
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Yang J, Kunimoto H, Katayama B, Zhao H, Shiromizu T, Wang L, Ozawa T, Tomonaga T, Tsuruta D, Nakajima K. Phospho-Ser727 triggers a multistep inactivation of STAT3 by rapid dissociation of pY705-SH2 through C-terminal tail modulation. Int Immunol 2020; 32:73-88. [PMID: 31555812 PMCID: PMC10689346 DOI: 10.1093/intimm/dxz061] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Accepted: 09/18/2019] [Indexed: 12/21/2022] Open
Abstract
Signal transducer and activator of transcription 3 (STAT3) is involved in many biological processes, including immunity and cancer. STAT3 becomes phosphorylated at Tyr705 and Ser727 on IL-6 stimulation. Phospho-Tyr705 (pY705) stabilizes the STAT3 dimer with reciprocal interactions between pY705 and the SH2 of the other molecule and phospho-Ser727 (pS727) accelerates pY705 dephosphorylation. We study how pS727 regulates STAT3 in both structural and biological perspectives. Using STAT3 reconstituted in HepG2-stat3-knockout cells, we show that pS727, together with a handshake N-terminal domain (NTD) interaction, causes rapid inactivation of STAT3 for pY705 dephosphorylation and a chromosome region maintenance 1 (CRM1)-independent nuclear export, which is critical for faithful STAT3 response to the cellular signals. The various N-terminal tags, GFP-related Ruby and FLAG, rendered the export CRM1-dependent and especially FLAG-tag caused nuclear accumulation of STAT3, indicating the presence of conformational changes in inactivation. Impaired reactivation of STAT3 by S727A or FLAG-tag delayed or inhibited the IL-6-induced saa1 mRNA expression, respectively. The detailed analysis of the pY705-SH2 structure identified the C-terminal tail (CTT) from L706 to P715 as a key regulator of the CTT-CTT intermolecular and the CTT-SH2 intramolecular interactions that support pY705-SH2 association. The functional studies using multiple STAT3 mutants indicated that the degree of the two interactions determines the stability of pY705-SH2 interaction. Importantly, Pro715 was critical for the pS727's destabilizing activity and the known phosphorylation and acetylation at the CTT structurally inhibited the pY705-SH2 interaction. Thus, pS727 triggers pY705-SH2 dissociation by weakening the supportive interactions likely through CTT modulation, inducing rapid cycles of STAT3 activation-inactivation for proper function of STAT3.
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Affiliation(s)
- Junhao Yang
- Department of Immunology, Osaka City University Graduate School of Medicine, Osaka, Japan
| | - Hiroyuki Kunimoto
- Department of Immunology, Osaka City University Graduate School of Medicine, Osaka, Japan
| | - Bumpei Katayama
- Department of Dermatology, Osaka City University Graduate School of Medicine, Osaka, Japan
| | - Hong Zhao
- Department of Immunology, Osaka City University Graduate School of Medicine, Osaka, Japan
| | - Takashi Shiromizu
- Laboratory of Proteome Research, National Institute of Biomedical Innovation, Health and Nutrition, Ibaraki, Osaka, Japan
| | - Lingyu Wang
- Department of Immunology, Osaka City University Graduate School of Medicine, Osaka, Japan
| | - Toshiyuki Ozawa
- Department of Dermatology, Osaka City University Graduate School of Medicine, Osaka, Japan
| | - Takeshi Tomonaga
- Laboratory of Proteome Research, National Institute of Biomedical Innovation, Health and Nutrition, Ibaraki, Osaka, Japan
| | - Daisuke Tsuruta
- Department of Dermatology, Osaka City University Graduate School of Medicine, Osaka, Japan
| | - Koichi Nakajima
- Department of Immunology, Osaka City University Graduate School of Medicine, Osaka, Japan
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10
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Vandenberghe LTM, Heindryckx B, Smits K, Popovic M, Szymanska K, Bonte D, Peelman L, Deforce D, De Sutter P, Van Soom A, De Schauwer C. Intracellular localisation of platelet-activating factor during mammalian embryo development in vitro: a comparison of cattle, mouse and human. Reprod Fertil Dev 2018; 31:658-670. [PMID: 30458920 DOI: 10.1071/rd18146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Accepted: 10/05/2018] [Indexed: 11/23/2022] Open
Abstract
Platelet-activating factor (PAF) is a well-known marker for embryo quality and viability. For the first time, we describe an intracellular localisation of PAF in oocytes and embryos of cattle, mice and humans. We showed that PAF is represented in the nucleus, a signal that was lost upon nuclear envelope breakdown. This process was confirmed by treating the embryos with nocodazole, a spindle-disrupting agent that, as such, arrests the embryo in mitosis, and by microinjecting a PAF-specific antibody in bovine MII oocytes. The latter resulted in the absence of nuclear PAF in the pronuclei of the zygote and reduced further developmental potential. Previous research indicates that PAF is released and taken up from the culture medium by preimplantation embryos invitro, in which bovine serum albumin (BSA) serves as a crucial carrier molecule. In the present study we demonstrated that nuclear PAF does not originate from an extracellular source because embryos cultured in polyvinylpyrrolidone or BSA showed similar levels of PAF in their nuclei. Instead, our experiments indicate that cytosolic phospholipase A2 (cPLA2) is likely to be involved in the intracellular production of PAF, because treatment with arachidonyl trifluoromethyl ketone (AACOCF3), a specific cPLA2 inhibitor, clearly lowered PAF levels in the nuclei of bovine embryos.
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Affiliation(s)
- L T M Vandenberghe
- Department of Reproduction, Obstetrics and Herd Health, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium
| | - B Heindryckx
- Ghent-Fertility and Stem cell Team (G-FaST), Department for Reproductive Medicine, Ghent University Hospital, De Pintelaan 185, 9000 Ghent, Belgium
| | - K Smits
- Department of Reproduction, Obstetrics and Herd Health, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium
| | - M Popovic
- Ghent-Fertility and Stem cell Team (G-FaST), Department for Reproductive Medicine, Ghent University Hospital, De Pintelaan 185, 9000 Ghent, Belgium
| | - K Szymanska
- Physiology Group, Department of Basic Medical Sciences, Ghent University, De Pintelaan 185, 9000 Ghent, Belgium
| | - D Bonte
- Ghent-Fertility and Stem cell Team (G-FaST), Department for Reproductive Medicine, Ghent University Hospital, De Pintelaan 185, 9000 Ghent, Belgium
| | - L Peelman
- Department of Nutrition, Genetics and Ethology, Faculty of Veterinary Medicine, Ghent University, Heidestraat 19, 9820 Merelbeke, Belgium
| | - D Deforce
- Laboratory of Pharmaceutical Biotechnology, Ghent University, Harelbekestraat 72, 9000 Ghent, Belgium
| | - P De Sutter
- Ghent-Fertility and Stem cell Team (G-FaST), Department for Reproductive Medicine, Ghent University Hospital, De Pintelaan 185, 9000 Ghent, Belgium
| | - A Van Soom
- Department of Reproduction, Obstetrics and Herd Health, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium
| | - C De Schauwer
- Department of Reproduction, Obstetrics and Herd Health, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium
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11
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Riebeling T, Staab J, Herrmann-Lingen C, Meyer T. DNA binding reduces the dissociation rate of STAT1 dimers and impairs the interdimeric exchange of protomers. BMC BIOCHEMISTRY 2014; 15:28. [PMID: 25526807 PMCID: PMC4284922 DOI: 10.1186/s12858-014-0028-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/24/2014] [Accepted: 12/11/2014] [Indexed: 01/14/2023]
Abstract
BACKGROUND A shift between two dimer conformations has been proposed for the transcription factor STAT1 (signal transducer and activator of transcription 1) which links DNA binding of the parallel dimer to tyrosine dephosphorylation of the antiparallel dimer as two consecutive and important steps in interferon- γ (IFNγ)-mediated signalling. However, neither the kinetics nor the molecular mechanisms involved in this conformational transition have been determined so far. RESULTS Our results demonstrated that the dissociation of dimers into monomers and their subsequent re-association into newly formed tyrosine-phosphorylated dimers is a relatively slow process as compared to the fast release from high-affinity DNA-binding sites, termed GAS (gamma-activated sequence). In addition, we noted an inhibitory effect of GAS binding on the exchange rate of protomers, indicating that DNA binding substantially impedes the recombination of dimeric STAT1. Furthermore, we found that reciprocal aminoterminal interactions between two STAT1 molecules are not required for the interchange of protomers, as an oligomerization-deficient point mutant displayed similar interdimeric exchange kinetics as the wild-type molecule. CONCLUSIONS Our results demonstrate that DNA binding impairs the oscillation rate between STAT1 conformers. Furthermore, these data suggest that the rapid release from high-affinity GAS sites is not a rate-limiting step in IFNγ-mediated signal transduction. Further investigations are needed to decipher the physiological significance of the observed dissociation/re-association process of STAT1 dimers.
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Affiliation(s)
- Theresa Riebeling
- Klinik für Psychosomatische Medizin und Psychotherapie, Georg-August-Universität Göttingen, Waldweg 33, 37073, Göttingen, Germany.
| | - Julia Staab
- Klinik für Psychosomatische Medizin und Psychotherapie, Georg-August-Universität Göttingen, Waldweg 33, 37073, Göttingen, Germany.
| | - Christoph Herrmann-Lingen
- Klinik für Psychosomatische Medizin und Psychotherapie, Georg-August-Universität Göttingen, Waldweg 33, 37073, Göttingen, Germany.
| | - Thomas Meyer
- Klinik für Psychosomatische Medizin und Psychotherapie, Georg-August-Universität Göttingen, Waldweg 33, 37073, Göttingen, Germany.
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12
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Abstract
Lanthanide bioprobes and bioconjugates are ideal luminescent stains in view of their low propensity to photobleaching, sharp emission lines and long excited state lifetimes permitting time-resolved detection for enhanced sensitivity. We show here how the interplay between physical, chemical and biochemical properties allied to microfluidics engineering leads to self-assembled dinuclear lanthanide luminescent probes illuminating live cells and selectively detecting biomarkers expressed by cancerous human breast cells.
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Affiliation(s)
- Jean-Claude G Bünzli
- Institute of Chemical Sciences and Engineering , École Polytechnique Fédérale de Lausanne , BCH 1402, 1015 Lausanne , Switzerland
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13
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STAT1-cooperative DNA binding distinguishes type 1 from type 2 interferon signaling. Nat Immunol 2014; 15:168-76. [PMID: 24413774 DOI: 10.1038/ni.2794] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2013] [Accepted: 11/18/2013] [Indexed: 12/15/2022]
Abstract
STAT1 is an indispensable component of a heterotrimer (ISGF3) and a STAT1 homodimer (GAF) that function as transcription regulators in type 1 and type 2 interferon signaling, respectively. To investigate the importance of STAT1-cooperative DNA binding, we generated gene-targeted mice expressing cooperativity-deficient STAT1 with alanine substituted for Phe77. Neither ISGF3 nor GAF bound DNA cooperatively in the STAT1F77A mouse strain, but type 1 and type 2 interferon responses were affected differently. Type 2 interferon-mediated transcription and antibacterial immunity essentially disappeared owing to defective promoter recruitment of GAF. In contrast, STAT1 recruitment to ISGF3 binding sites and type 1 interferon-dependent responses, including antiviral protection, remained intact. We conclude that STAT1 cooperativity is essential for its biological activity and underlies the cellular responses to type 2, but not type 1 interferon.
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14
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The detection and quantitation of protein oligomerization. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 747:19-41. [PMID: 22949109 DOI: 10.1007/978-1-4614-3229-6_2] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
There are many different techniques available to biologists and biochemists that can be used to detect and characterize the self-association of proteins. Each technique has strengths and weaknesses and it is often useful to combine several approaches to maximize the former and minimize the latter. Here we review a range of methodologies that identify protein self-association and/or allow the stoichiometry and affinity of the interaction to be determined, placing an emphasis on what type of information can be obtained and outlining the advantages and disadvantages involved. In general, in vitro biophysical techniques, such as size exclusion chromatography, analytical ultracentrifugation, scattering techniques, NMR spectroscopy, isothermal titration calorimetry, fluorescence anisotropy and mass spectrometry, provide information on stoichiometry and/or binding affinities. Other approaches such as cross-linking, fluorescence methods (e.g., fluorescence correlation spectroscopy, FCS; Förster resonance energy transfer, FRET; fluorescence recovery after photobleaching, FRAP; and proximity imaging, PRIM) and complementation approaches (e.g., yeast two hybrid assays and bimolecular fluorescence complementation, BiFC) can be used to detect protein self-association in a cellular context.
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15
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David-Watine B. Silencing nuclear pore protein Tpr elicits a senescent-like phenotype in cancer cells. PLoS One 2011; 6:e22423. [PMID: 21811608 PMCID: PMC3139644 DOI: 10.1371/journal.pone.0022423] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2011] [Accepted: 06/22/2011] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Tpr is a large coiled-coil protein located in the nuclear basket of the nuclear pore complex for which many different functions were proposed from yeast to human. METHODOLOGY/PRINCIPAL FINDINGS Here we show that depletion of Tpr by RNA interference triggers G0-G1 arrest and ultimately induces a senescent-like phenotype dependent on the presence of p53. We also found that Tpr depletion impairs the NES [nuclear export sequence]-dependent nuclear export of proteins and causes partial co-depletion of Nup153. In addition Tpr depletion impacts on level and function of the SUMO-protease SENP2 thus affecting SUMOylation regulation at the nuclear pore and overall SUMOylation in the cell. CONCLUSIONS Our data for the first time provide evidence that a nuclear pore component plays a role in controlling cellular senescence. Our findings also point to new roles for Tpr in the regulation of SUMO-1 conjugation at the nuclear pore and directly confirm Tpr involvement in the nuclear export of NES-proteins.
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Affiliation(s)
- Brigitte David-Watine
- Institut Pasteur, CNRS URA2582, Groupe E3 Biologie Cellulaire du Noyau, Paris, France.
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16
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Meyer T, Vinkemeier U. Assessing sequence-specific DNA binding and transcriptional activity of STAT1 transcription factor. Methods Mol Biol 2010; 647:139-59. [PMID: 20694665 DOI: 10.1007/978-1-60761-738-9_8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
Continuous nucleocytoplasmic shuttling of signal transducer and activator of transcription (STAT) proteins is a key to understand their function as cytokine-responsive transcription factors. STATs enter the nucleus both by carrier-dependent and carrier-independent transport pathways, and it was previously shown that STAT1 exits the nucleus only after its prior enzymatic dephosphorylation by nuclear phosphatases. The identification of different transport pathways for unphosphorylated and tyrosine-phosphorylated STAT dimers was made possible by a combination of a diverse set of experimental approaches in the field of molecular biology. In the following, we will summarize some of the techniques that have been successfully used to decipher molecular mechanisms engaged in STAT1 dynamics.
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Affiliation(s)
- Thomas Meyer
- Department of Cardiology, University of Marburg, Baldingerstrasse, Marburg, Germany
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17
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Drake KR, Kang M, Kenworthy AK. Nucleocytoplasmic distribution and dynamics of the autophagosome marker EGFP-LC3. PLoS One 2010; 5:e9806. [PMID: 20352102 PMCID: PMC2843706 DOI: 10.1371/journal.pone.0009806] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2009] [Accepted: 02/28/2010] [Indexed: 01/07/2023] Open
Abstract
The process of autophagy involves the formation of autophagosomes, double-membrane structures that encapsulate cytosol. Microtubule-associated protein light chain 3 (LC3) was the first protein shown to specifically label autophagosomal membranes in mammalian cells, and subsequently EGFP-LC3 has become one of the most widely utilized reporters of autophagy. Although LC3 is currently thought to function primarily in the cytosol, the site of autophagosome formation, EGFP-LC3 often appears to be enriched in the nucleoplasm relative to the cytoplasm in published fluorescence images. However, the nuclear pool of EGFP-LC3 has not been specifically studied in previous reports, and mechanisms by which LC3 shuttles between the cytoplasm and nucleoplasm are currently unknown. In this study, we therefore investigated the regulation of the nucleo-cytoplasmic distribution of EGFP-LC3 in living cells. By quantitative fluorescence microscopy analysis, we demonstrate that soluble EGFP-LC3 is indeed enriched in the nucleus relative to the cytoplasm in two commonly studied cell lines, COS-7 and HeLa. Although LC3 contains a putative nuclear export signal (NES), inhibition of active nuclear export or mutation of the NES had no effect on the nucleo-cytoplasmic distribution of EGFP-LC3. Furthermore, FRAP analysis indicates that EGFP-LC3 undergoes limited passive nucleo-cytoplasmic transport under steady state conditions, and that the diffusional mobility of EGFP-LC3 was substantially slower in the nucleus and cytoplasm than predicted for a freely diffusing monomer. Induction of autophagy led to a visible decrease in levels of soluble EGFP-LC3 relative to autophagosome-bound protein, but had only modest effects on the nucleo-cytoplasmic ratio or diffusional mobility of the remaining soluble pools of EGFP-LC3. We conclude that the enrichment of soluble EGFP-LC3 in the nucleus is maintained independently of active nuclear export or induction of autophagy. Instead, incorporation of soluble EGFP-LC3 into large macromolecular complexes within both the cytoplasm and nucleus may prevent its rapid equilibrium between the two compartments.
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Affiliation(s)
- Kimberly R. Drake
- Department of Molecular Physiology and Biophysics, Vanderbilt School of Medicine, Nashville, Tennessee, United States of America
| | - Minchul Kang
- Department of Molecular Physiology and Biophysics, Vanderbilt School of Medicine, Nashville, Tennessee, United States of America
| | - Anne K. Kenworthy
- Department of Molecular Physiology and Biophysics, Vanderbilt School of Medicine, Nashville, Tennessee, United States of America
- Department of Cell and Developmental Biology, Vanderbilt School of Medicine, Nashville, Tennessee, United States of America
- * E-mail:
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18
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Ebolavirus VP24 binding to karyopherins is required for inhibition of interferon signaling. J Virol 2009; 84:1169-75. [PMID: 19889762 DOI: 10.1128/jvi.01372-09] [Citation(s) in RCA: 99] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The Ebolavirus VP24 protein counteracts alpha/beta interferon (IFN-alpha/beta) and IFN-gamma signaling by blocking the nuclear accumulation of tyrosine-phosphorylated STAT1 (PY-STAT1). According to the proposed model, VP24 binding to members of the NPI-1 subfamily of karyopherin alpha (KPNalpha) nuclear localization signal receptors prevents their binding to PY-STAT1, thereby preventing PY-STAT1 nuclear accumulation. This study now identifies two domains of VP24 required for inhibition of IFN-beta-induced gene expression and PY-STAT1 nuclear accumulation. We demonstrate that loss of function correlates with loss of binding to KPNalpha proteins. Thus, the VP24 IFN antagonist function requires the ability of VP24 to interact with KPNalpha.
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19
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Marg A, Meyer T, Vigneron M, Vinkemeier U. Microinjected antibodies interfere with protein nucleocytoplasmic shuttling by distinct molecular mechanisms. Cytometry A 2009; 73A:1128-40. [PMID: 18773464 DOI: 10.1002/cyto.a.20635] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The observation that some antibodies can enter the nucleus after their microinjection into the cytoplasm established the principle of protein nucleocytoplasmic shuttling. Here, we introduce the concept of stationary antibodies for studying nuclear transport, particularly of native proteins. Contrary to the aforementioned translocating immunoglobulins, stationary antibodies do not cross the nuclear envelope. They are distinguished by their ability to trigger the nucleocytoplasmic redistribution of their antigen. What determines these apparently contradictory outcomes has not been explored. We studied a stationary STAT1 antibody and a translocating importin-beta antibody. The stationary phenotype resulted from the inhibition of carrier-independent transport. This was not due to crosslinking or precipitation of antigen, because the antigen-antibody complex remained highly mobile. Rather, decoration with stationary antibody precluded actual nuclear pore passage of antigen. In addition, both antibodies inhibited the carrier-dependent translocation via importin-alpha, but by diverse mechanisms. The translocating antibody blocked the association with importin-alpha, whereas the stationary antibody prevented the phosphorylation of its antigen, and thus functioned upstream of the importin-alpha binding step. We identified a stationary antibody to green-fluorescent protein (GFP) and probed the translocation of GFP fusions of STAT1, thyroid hormone receptor and histones, demonstrating general application of this approach. Our results provide an experimental rationale for the use of antibodies as unique tools for dissecting protein nuclear translocation. As the microinjection of stationary antibodies extends to analyses of native proteins, this method can complement and validate results obtained with fluorescent-labeled derivatives.
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Affiliation(s)
- Andreas Marg
- Abteilung Molekulare Muskelphysiologie, Max-Delbrück-Centrum für Molekulare Medizin, 13125 Berlin, Germany
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20
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Han F, Luo Y, Ge N, Xu J. Construction of fluorescence resonance energy transfer vectors and their application in study of structure and function of signal transducers and activators of transcription 1. Acta Biochim Biophys Sin (Shanghai) 2008; 40:934-42. [PMID: 18989574 DOI: 10.1111/j.1745-7270.2008.00480.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Protein-protein interactions have been studied extensively by green fluorescent protein-based fluorescence resonance energy transfer (FRET). The fluorescent proteins (FP) can be fused either to the N- or C-terminus of a host protein, but it is difficult to predict which order will perturb the host protein the least and provide the largest FRET. Therefore, a researcher needs to fuse host proteins with FP at both the N- and C-termini and test every possible combination (N-N, N-C, or C-C) to promote the energy transfer efficiency. Consequently, researchers required to do many subclonings. Herein, we designed FRET vectors to make them more efficient. The expression vectors of pCFP-YFP and pYFP-CFP were constructed with both cyan fluorescent protein (CFP)-yellow fluorescent protein (YFP) and YFP-CFP coding sequences flanked by two restriction enzyme sites, and with multiple cloning regions in the middle of both coding sequences. To select an optimal combination for FRET detection, we created plasmids encoding various fusion proteins of FP and signal transducers and activators of transcription 1 (STAT1) . We found that the nuclear:cytoplasmic fluorescence intensity ratios of STAT1-FP were significantly higher than those of FP-STAT1 at steady state, and fluorescence redistribution was only observed for STAT1-FP upon interferon gamma (IFNgamma) stimulation. In addition, positive FRET signals were only detected in the C-C interactions of STAT1 homodimer. Taken together, these data indicate that fusing STAT1 at the N-terminus with FP impairs the interactions of unphosphorylated STAT1 homodimers and possibly diminishes its binding with DNA. In contrast, STAT1-FP was functional with respect to its activation. Moreover, the FRET vectors are able to facilitate FRET studies.
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Affiliation(s)
- Fujun Han
- Guangzhou Medical College, Guangzhou Institute of Respiratory Diseases, Guangzhou 510120, China
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21
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Abstract
Signalling in multicellular organisms is mediated by complex networks that integrate extracellular and intracellular signals to generate appropriate responses regulating cell proliferation, differentiation and survival. Downstream of many cytokine and growth hormone receptors, receptor-associated JAKs (Janus kinases) activate transcription factors of the STAT (signal transducer and activator of transcription) protein family and thereby mediate signal transduction from the plasma membrane to the nucleus. The JAK/STAT pathway has been shown to be constitutively activated in a wide array of human malignancies. To elucidate mechanisms contributing to tumour formation and identify system properties of the JAK/STAT signalling pathway, a systems biology approach can be employed. So far the majority of studies available have focused on down-regulation of the signalling pathway based on simulations. However, a data-based model of the core module of the JAK2/STAT5 signalling pathway showed that rapid nucleocytoplasmic cycling of STAT5 is an essential pathway property. In the future, combining assays for quantitative analysis at different levels will be important to gain deeper insight into molecular mechanisms regulating intracellular communication mediated by such complex dynamic systems as signalling pathways and their targets.
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22
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Sehgal PB. Paradigm shifts in the cell biology of STAT signaling. Semin Cell Dev Biol 2008; 19:329-40. [PMID: 18691663 DOI: 10.1016/j.semcdb.2008.07.003] [Citation(s) in RCA: 100] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2007] [Revised: 07/15/2008] [Accepted: 07/17/2008] [Indexed: 01/25/2023]
Abstract
In recent years several of the key tenets of the original cytokine-STAT-signaling paradigm had to be revised. First, the notion that nonphosphorylated "inactive" STATs are present in the cytoplasm as free monomers which dimerized only subsequent to Tyr-phosphorylation has been replaced by the understanding that nonphosphorylated STATs in the cytoplasm exist largely as dimers and high molecular mass "statosome" complexes. Second, the notion that phosphorylation, either of Tyr or Ser residues or both, in STAT species is required for transcriptional activation has been replaced by the realization that nonphosphorylated STATs can be transcriptionally active albeit with respect to sets of target genes distinct from phosphorylated STATs. Third, the notion that it is the activation by phosphorylation of STATs at the plasma membrane that then leads to their import into the nucleus has been replaced by the recognition that even nonphosphorylated STATs shuttle between the cytoplasm and nucleus at all times in a constitutive manner. Fourth, the notion that the trans-cytoplasmic transit of STATs from the plasma membrane to the nuclear import machinery takes place exclusively as a free cytosolic process has been replaced by the understanding that at least a portion of this trans-cytoplasmic transit is mediated via membrane-associated caveolar and endocytic trafficking (the "signaling endosome" hypothesis). Fifth, the targeting and sequestration of activated STAT3 to long-lived endosomes in the cytoplasm requires consideration of STAT3-mediated "signal transduction" from the plasma membrane to cytoplasmic membrane destinations potentially for function(s) in the cytoplasm. Indeed, in tissue sections many discrete histologic cell types display PY-STAT3 almost exclusively in the cytoplasm with little, if any, in the nucleus. New challenges include determining the structural bases for the recruitment of nonphosphorylated dimeric STAT species to the cytosolic face of membranes including at the cytoplasmic tails of respective receptor complexes, the conformational changes subsequent to phosphorylation and the structural bases for the targeting and functions of STAT proteins within the cytoplasm per se.
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Affiliation(s)
- Pravin B Sehgal
- Department of Cell Biology & Anatomy, New York Medical College, Valhalla, NY 10595, United States.
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23
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Recruitment of Stat1 to chromatin is required for interferon-induced serine phosphorylation of Stat1 transactivation domain. Proc Natl Acad Sci U S A 2008; 105:8944-9. [PMID: 18574148 DOI: 10.1073/pnas.0801794105] [Citation(s) in RCA: 115] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The transcription factor Stat1 plays an essential role in responses to interferons (IFNs). Activation of Stat1 is achieved by phosphorylation on Y701 that is followed by nuclear accumulation. For full transcriptional activity and biological function Stat1 must also be phosphorylated on S727. The molecular mechanisms underlying the IFN-induced S727 phosphorylation are incompletely understood. Here, we show that both Stat1 Y701 phosphorylation and nuclear translocation are required for IFN-induced S727 phosphorylation. We further show that Stat1 mutants lacking the ability to stably associate with chromatin are poorly serine-phosphorylated in response to IFN-gamma. The S727 phosphorylation of these mutants is restored on IFN-beta treatment that induces the formation of the ISGF3 complex (Stat1/Stat2/Irf9) where Irf9 represents the main DNA binding subunit. These findings indicate that Stat1 needs to be assembled into chromatin-associated transcriptional complexes to become S727-phosphorylated and fully biologically active in response to IFNs. This control mechanism, which may be used by other Stat proteins as well, restricts the final activation step to the chromatin-tethered transcription factor.
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24
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Meyer T, Vinkemeier U. STAT nuclear translocation: potential for pharmacological intervention. Expert Opin Ther Targets 2007; 11:1355-65. [PMID: 17907964 DOI: 10.1517/14728222.11.10.1355] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The signal transducer and activator of transcription (STAT) proteins are extracellular ligand-responsive transcription factors that mediate broadly diverse biological processes, including cell proliferation, transformation, apoptosis, differentiation, fetal development, inflammation and immune response. Stimulation with multiple cytokines or growth factors all result in the tyrosine phosphorylation of STAT proteins and the subsequent gene regulation via their direct binding to the promoters of responsive genes. Cytokine-regulated gene activation is dependent on the continuous nucleocytoplasmic cycling of STAT signal transducers. The STATs use intricately intertwined karyopherin-dependent and -independent translocation mechanisms to coordinate the activation step at the cell membrane and gene expression in the nucleus. In addition, STATs appear to have cytokine-independent gene regulatory functions that may also depend on their regulated nucleocytoplasmic transfer. Numerous studies have implicated aberrant STAT signalling in cancer, immune defects and inflammatory diseases. Given the central role of intracellular trafficking for the proper signal processing by STAT proteins, pharmacological targeting of STAT nucleocytoplasmic translocation appears to be an attractive strategy to interfere with dysregulated cytokine signalling. This review will discuss possible scenarios that would result from the use of novel modulators of STAT shuttling, which may both increase or decrease STAT activation and, hence, transcriptional activity.
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Affiliation(s)
- Thomas Meyer
- Philipps-Universität Marburg, Klinik für Kardiologie und Klinik für Psychosomatische Medizin und Psychotherapie, Baldingerstrasse 1, 35033 Marburg, Germany.
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25
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Xu F, Mukhopadhyay S, Sehgal PB. Live cell imaging of interleukin-6-induced targeting of "transcription factor" STAT3 to sequestering endosomes in the cytoplasm. Am J Physiol Cell Physiol 2007; 293:C1374-82. [PMID: 17670892 DOI: 10.1152/ajpcell.00220.2007] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Signal transducer and activator of transcription (STAT) family transcription factors are classically viewed as transducing cytokine- and growth factor-activated signals from the plasma membrane to the cell nucleus for the purpose of activating transcription. We report live cell imaging studies of fluorescently labeled STAT3 expressed in Hep3B hepatocytes that reveal interleukin (IL)-6-activated targeting of STAT3 and PY-STAT3 to relatively long-lived sequestering endosomes in the cytoplasm. This targeting was rapid but transient, required phosphorylation and integrity of Tyr 705 in STAT3, and was blocked by nocodazole, geldanamycin, and indirubin E804 and by overexpression of wild-type caveolin-1. Strikingly, overexpression of the dominant-negative (DN) mutant K44A of the GTPase dynamin II led to marked constitutive accumulation of STAT3 in the endocytic compartment with depletion of the STAT3 nuclear pool. Subsets of the native and K44A-generated STAT3- and PY-STAT3-sequestering endosomes colocalized with MyD88, an adapter protein that integrates pathways of Toll-like receptor and IL-1 transcriptional signaling and stabilization of mRNAs. These data provide direct evidence for the cytokine-induced "signal transduction" by STAT3 from the plasma membrane to a cytoplasmic membrane destination for yet to be elucidated function(s) in the cytoplasm including prolongation of signaling and/or cross talk.
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Affiliation(s)
- Fang Xu
- Department of Cell Biology & Anatomy, New York Medical College, Valhalla, NY 10595, USA
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