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Oliveira PVS, Dalla Torre M, Debbas V, Orsi A, Laurindo FRM, Sitia R. Transport of protein disulfide isomerase from the endoplasmic reticulum to the extracellular space without passage through the Golgi complex. J Biol Chem 2024; 300:107536. [PMID: 38971317 DOI: 10.1016/j.jbc.2024.107536] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2024] [Revised: 05/29/2024] [Accepted: 06/21/2024] [Indexed: 07/08/2024] Open
Abstract
Protein disulfide isomerase-A1 (PDIA1) is a master regulator of oxidative protein folding and proteostasis in the endoplasmic reticulum (ER). However, PDIA1 can reach the extracellular space, impacting thrombosis and other pathophysiological phenomena. Whether PDIA1 is externalized via passive release or active secretion is not known. To investigate how PDIA1 negotiates its export, we generated a tagged variant that undergoes N-glycosylation in the ER (Glyco-PDIA1). Addition of N-glycans does not alter its enzymatic functions. Upon either deletion of its KDEL ER-localization motif or silencing of KDEL receptors, Glyco-PDIA1 acquires complex glycans in the Golgi and is secreted. In control cells, however, Glyco-PDIA1 is released with endoglycosidase-H sensitive glycans, implying that it does not follow the classical ER-Golgi route nor does it encounter glycanases in the cytosol. Extracellular Glyco-PDIA1 is more abundant than actin, lactate dehydrogenase, or other proteins released by damaged or dead cells, suggesting active transport through a Golgi-independent route. The strategy we describe herein can be extended to dissect how select ER-residents reach the extracellular space.
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Affiliation(s)
- Percillia Victoria Santos Oliveira
- Division of Genetics and Cell Biology Vita-Salute San Raffaele University and IRCCS San Raffaele Scientific Institute, Milan, Italy; Laboratorio de Biologia Vascular, LIM-64 (Biologia Cardiovascular Translacional), Instituto do Coração (InCor), Hospital das Clinicas HCFMUSP, Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP, Brasil
| | - Marco Dalla Torre
- Division of Genetics and Cell Biology Vita-Salute San Raffaele University and IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Victor Debbas
- Laboratorio de Biologia Vascular, LIM-64 (Biologia Cardiovascular Translacional), Instituto do Coração (InCor), Hospital das Clinicas HCFMUSP, Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP, Brasil
| | - Andrea Orsi
- Division of Genetics and Cell Biology Vita-Salute San Raffaele University and IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Francisco Rafael Martins Laurindo
- Laboratorio de Biologia Vascular, LIM-64 (Biologia Cardiovascular Translacional), Instituto do Coração (InCor), Hospital das Clinicas HCFMUSP, Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP, Brasil.
| | - Roberto Sitia
- Division of Genetics and Cell Biology Vita-Salute San Raffaele University and IRCCS San Raffaele Scientific Institute, Milan, Italy.
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Aktalay A, Khan TA, Bossi ML, Belov VN, Hell SW. Photoactivatable Carbo- and Silicon-Rhodamines and Their Application in MINFLUX Nanoscopy. Angew Chem Int Ed Engl 2023; 62:e202302781. [PMID: 37555720 DOI: 10.1002/anie.202302781] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Revised: 08/05/2023] [Accepted: 08/08/2023] [Indexed: 08/10/2023]
Abstract
New photoactivatable fluorescent dyes (rhodamine, carbo- and silicon-rhodamines [SiR]) with emission ranging from green to far red have been prepared, and their photophysical properties studied. The photocleavable 2-nitrobenzyloxycarbonyl unit with an alpha-carboxyl group as a branching point and additional functionality was attached to a polycyclic and lipophilic fluorescent dye. The photoactivatable probes having the HaloTagTM amine (O2) ligand bound with a dye core were obtained and applied for live-cell staining in stable cell lines incorporating Vimentin (VIM) or Nuclear Pore Complex Protein NUP96 fused with the HaloTag. The probes were applied in 2D (VIM, NUP96) and 3D (VIM) MINFLUX nanoscopy, as well as in superresolution fluorescence microscopy with single fluorophore activation (VIM, live-cell labeling). Images of VIM and NUPs labeled with different dyes were acquired and their apparent dimensions and shapes assessed on a lower single-digit nanometer scale. Applicability and performance of the photoactivatable dye derivatives were evaluated in terms of photoactivation rate, labeling and detection efficiency, number of detected photons per molecule and other parameters related to MINFLUX nanoscopy.
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Affiliation(s)
- Ayse Aktalay
- Department of Optical Nanoscopy, Max Planck Institute for Medical Research (MPI-MR), Jahnstraße 29, 69120, Heidelberg, Germany
| | - Taukeer A Khan
- Department of NanoBiophotonics, Max Planck Institute for Multidisciplinary Sciences (MPI-NAT), Am Fassberg 11, 37077, Göttingen, Germany
| | - Mariano L Bossi
- Department of Optical Nanoscopy, Max Planck Institute for Medical Research (MPI-MR), Jahnstraße 29, 69120, Heidelberg, Germany
| | - Vladimir N Belov
- Department of NanoBiophotonics, Max Planck Institute for Multidisciplinary Sciences (MPI-NAT), Am Fassberg 11, 37077, Göttingen, Germany
| | - Stefan W Hell
- Department of Optical Nanoscopy, Max Planck Institute for Medical Research (MPI-MR), Jahnstraße 29, 69120, Heidelberg, Germany
- Department of NanoBiophotonics, Max Planck Institute for Multidisciplinary Sciences (MPI-NAT), Am Fassberg 11, 37077, Göttingen, Germany
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Veeck C, Biedenkopf N, Rohde C, Becker S, Halwe S. Inhibition of Rab1B Impairs Trafficking and Maturation of SARS-CoV-2 Spike Protein. Viruses 2023; 15:v15040824. [PMID: 37112806 PMCID: PMC10145535 DOI: 10.3390/v15040824] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Revised: 03/09/2023] [Accepted: 03/21/2023] [Indexed: 04/29/2023] Open
Abstract
Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) utilizes cellular trafficking pathways to process its structural proteins and move them to the site of assembly. Nevertheless, the exact process of assembly and subcellular trafficking of SARS-CoV-2 proteins remains largely unknown. Here, we have identified and characterized Rab1B as an important host factor for the trafficking and maturation of the spike protein (S) after synthesis at the endoplasmic reticulum (ER). Using confocal microscopy, we showed that S and Rab1B substantially colocalized in compartments of the early secretory pathway. Co-expression of dominant-negative (DN) Rab1B N121I leads to an aberrant distribution of S into perinuclear spots after ectopic expression and in SARS-CoV-2-infected cells caused by either structural rearrangement of the ERGIC or Golgi or missing interaction between Rab1B and S. Western blot analyses revealed a complete loss of the mature, cleaved S2 subunit in cell lysates and culture supernatants upon co-expression of DN Rab1B N121I. In sum, our studies indicate that Rab1B is an important regulator of trafficking and maturation of SARS-CoV-2 S, which not only improves our understanding of the coronavirus replication cycle but also may have implications for the development of antiviral strategies.
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Affiliation(s)
- Christopher Veeck
- Institute of Virology, Philipps University Marburg, 35043 Marburg, Germany
| | - Nadine Biedenkopf
- Institute of Virology, Philipps University Marburg, 35043 Marburg, Germany
- German Center for Infection Research (DZIF), Partner Site Giessen-Marburg-Langen, 35043 Marburg, Germany
| | - Cornelius Rohde
- Institute of Virology, Philipps University Marburg, 35043 Marburg, Germany
- German Center for Infection Research (DZIF), Partner Site Giessen-Marburg-Langen, 35043 Marburg, Germany
| | - Stephan Becker
- Institute of Virology, Philipps University Marburg, 35043 Marburg, Germany
- German Center for Infection Research (DZIF), Partner Site Giessen-Marburg-Langen, 35043 Marburg, Germany
| | - Sandro Halwe
- Institute of Virology, Philipps University Marburg, 35043 Marburg, Germany
- German Center for Infection Research (DZIF), Partner Site Giessen-Marburg-Langen, 35043 Marburg, Germany
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A virtuous cycle operated by ERp44 and ERGIC-53 guarantees proteostasis in the early secretory compartment. iScience 2021; 24:102244. [PMID: 33763635 PMCID: PMC7973864 DOI: 10.1016/j.isci.2021.102244] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Revised: 02/01/2021] [Accepted: 02/25/2021] [Indexed: 01/13/2023] Open
Abstract
The composition of the secretome depends on the combined action of cargo receptors that facilitate protein transport and sequential checkpoints that restrict it to native conformers. Acting after endoplasmic reticulum (ER)-resident chaperones, ERp44 retrieves its clients from downstream compartments. To guarantee efficient quality control, ERp44 should exit the ER as rapidly as its clients, or more. Here, we show that appending ERp44 to different cargo proteins increases their secretion rates. ERp44 binds the cargo receptor ER-Golgi intermediate compartment (ERGIC)-53 in the ER to negotiate preferential loading into COPII vesicles. Silencing ERGIC-53, or competing for its COPII binding with 4-phenylbutyrate, causes secretion of Prdx4, an enzyme that relies on ERp44 for intracellular localization. In more acidic, zinc-rich downstream compartments, ERGIC-53 releases its clients and ERp44, which can bind and retrieve non-native conformers via KDEL receptors. By coupling the transport of cargoes and inspector proteins, cells ensure efficiency and fidelity of secretion.
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Cohen LD, Boulos A, Ziv NE. A non-fluorescent HaloTag blocker for improved measurement and visualization of protein synthesis in living cells. F1000Res 2020; 9. [PMID: 32518633 PMCID: PMC7255903 DOI: 10.12688/f1000research.23289.2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 06/03/2020] [Indexed: 11/20/2022] Open
Abstract
Background: HaloTag is a modified bacterial enzyme that binds rapidly and irreversibly to an array of synthetic ligands, including chemical dyes. When expressed in live cells in conjunction with a protein of interest, HaloTag can be used to study protein trafficking, synthesis, and degradation. For instance, sequential HaloTag labeling with spectrally separable dyes can be used to separate preexisting protein pools from proteins newly synthesized following experimental manipulations or the passage of time. Unfortunately, incomplete labeling by the first dye, or labeling by residual, trapped dye pools can confound interpretation. Methods: Labeling specificity of newly synthesized proteins could be improved by blocking residual binding sites. To that end, we synthesized a non-fluorescent, cell permeable blocker (1-chloro-6-(2-propoxyethoxy)hexane; CPXH), essentially the HaloTag ligand backbone without the reactive amine used to attach fluorescent groups. Results: High-content imaging was used to quantify the ability of CPXH to block HaloTag ligand binding in live HEK cells expressing a fusion protein of mTurquoise2 and HaloTag. Full saturation was observed at CPXH concentrations of 5-10 µM at 30 min. No overt effects on cell viability were observed at any concentration or treatment duration. The ability of CPXH to improve the reliability of newly synthesized protein detection was then demonstrated in live cortical neurons expressing the mTurquoise2-HaloTag fusion protein, in both single and dual labeling time lapse experiments. Practically no labeling was observed after blocking HaloTag binding sites with CPXH when protein synthesis was suppressed with cycloheximide, confirming the identification of newly synthesized protein copies as such, while providing estimates of protein synthesis suppression in these experiments. Conclusions: CPXH is a reliable (and inexpensive) non-fluorescent ligand for improving assessment of protein-of-interest metabolism in live cells using HaloTag technology.
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Affiliation(s)
- Laurie D Cohen
- Faculty of Medicine, Rappaport Institute and Network Biology Research Laboratories, Technion - Israel Institute of Technology, Haifa, 32000, Israel
| | - Ayub Boulos
- Faculty of Medicine, Rappaport Institute and Network Biology Research Laboratories, Technion - Israel Institute of Technology, Haifa, 32000, Israel
| | - Noam E Ziv
- Faculty of Medicine, Rappaport Institute and Network Biology Research Laboratories, Technion - Israel Institute of Technology, Haifa, 32000, Israel
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6
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Cohen LD, Boulos A, Ziv NE. A non-fluorescent HaloTag blocker for improved measurement and visualization of protein synthesis in living cells. F1000Res 2020; 9:ISF-302. [PMID: 32518633 PMCID: PMC7255903 DOI: 10.12688/f1000research.23289.1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 06/03/2020] [Indexed: 12/24/2023] Open
Abstract
Background: HaloTag is a modified bacterial enzyme that binds rapidly and irreversibly to an array of synthetic ligands, including chemical dyes. When expressed in live cells in conjunction with a protein of interest, HaloTag can be used to study protein trafficking, synthesis, and degradation. For instance, sequential HaloTag labeling with spectrally separable dyes can be used to separate preexisting protein pools from proteins newly synthesized following experimental manipulations or the passage of time. Unfortunately, incomplete labeling by the first dye, or labeling by residual, trapped dye pools can confound interpretation. Methods: Labeling specificity of newly synthesized proteins could be improved by blocking residual binding sites. To that end, we synthesized a non-fluorescent, cell permeable blocker (1-chloro-6-(2-propoxyethoxy)hexane; CPXH), essentially the HaloTag ligand backbone without the reactive amine used to attach fluorescent groups. Results: High-content imaging was used to quantify the ability of CPXH to block HaloTag ligand binding in live HEK cells expressing a fusion protein of mTurquoise2 and HaloTag. Full saturation was observed at CPXH concentrations of 5-10 µM at 30 min. No overt effects on cell viability were observed at any concentration or treatment duration. The ability of CPXH to improve the reliability of newly synthesized protein detection was then demonstrated in live cortical neurons expressing the mTurquoise2-HaloTag fusion protein, in both single and dual labeling time lapse experiments. Practically no labeling was observed after blocking HaloTag binding sites with CPXH when protein synthesis was suppressed with cycloheximide, confirming the identification of newly synthesized protein copies as such, while providing estimates of protein synthesis suppression in these experiments. Conclusions: CPXH is a reliable (and inexpensive) non-fluorescent ligand for improving assessment of protein-of-interest metabolism in live cells using HaloTag technology.
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Affiliation(s)
- Laurie D. Cohen
- Faculty of Medicine, Rappaport Institute and Network Biology Research Laboratories, Technion - Israel Institute of Technology, Haifa, 32000, Israel
| | - Ayub Boulos
- Faculty of Medicine, Rappaport Institute and Network Biology Research Laboratories, Technion - Israel Institute of Technology, Haifa, 32000, Israel
| | - Noam E. Ziv
- Faculty of Medicine, Rappaport Institute and Network Biology Research Laboratories, Technion - Israel Institute of Technology, Haifa, 32000, Israel
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Carotenuto G, Sciascia I, Oddi L, Volpe V, Genre A. Size matters: three methods for estimating nuclear size in mycorrhizal roots of Medicago truncatula by image analysis. BMC PLANT BIOLOGY 2019; 156:265-273. [PMID: 31054574 DOI: 10.1046/j.1469-8137.2002.00508.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
BACKGROUND The intracellular accommodation of arbuscular mycorrhizal (AM) fungi involves a profound molecular reprogramming of the host cell architecture and metabolism, based on the activation of a symbiotic signaling pathway. In analogy with other plant biotrophs, AM fungi are reported to trigger cell cycle reactivation in their host tissues, possibly in support of the enhanced metabolic demand required for the symbiosis. RESULTS We here compare the efficiency of three Fiji/ImageJ image analysis plugins in localizing and quantifying the increase in nuclear size - a hallmark of recursive events of endoreduplication - in M. truncatula roots colonized by the AM fungus Gigaspora margarita. All three approaches proved to be versatile and upgradeable, allowing the investigation of nuclear changes in a complex tissue; 3D Object Counter provided more detailed information than both TrackMate and Round Surface Detector plugins. On this base we challenged 3D Object Counter with two case studies: verifying the lack of endoreduplication-triggering responses in Medicago truncatula mutants with a known non-symbiotic phenotype; and analysing the correlation in space and time between the induction of cortical cell division and endoreduplication upon AM colonization. Both case studies revealed important biological aspects. Mutant phenotype analyses have demonstrated that the knock-out mutation of different key genes in the symbiotic signaling pathway block AM-associated endoreduplication. Furthermore, our data show that cell divisions occur during initial stages of root colonization and are followed by recursive activation of the endocycle in preparation for arbuscule accommodation. CONCLUSIONS In conclusion, our results indicate 3D Object Counter as the best performing Fiji/ImageJ image analysis script in plant root thick sections and its application highlighted endoreduplication as a major feature of the AM pre-penetration response in root cortical cells.
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Affiliation(s)
- Gennaro Carotenuto
- Department of Life Sciences and Systems Biology, University of Turin, 10125, Torino, Italy
| | - Ivan Sciascia
- Department of Life Sciences and Systems Biology, University of Turin, 10125, Torino, Italy
| | - Ludovica Oddi
- Department of Life Sciences and Systems Biology, University of Turin, 10125, Torino, Italy
| | - Veronica Volpe
- Department of Life Sciences and Systems Biology, University of Turin, 10125, Torino, Italy
| | - Andrea Genre
- Department of Life Sciences and Systems Biology, University of Turin, 10125, Torino, Italy.
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8
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Carotenuto G, Sciascia I, Oddi L, Volpe V, Genre A. Size matters: three methods for estimating nuclear size in mycorrhizal roots of Medicago truncatula by image analysis. BMC PLANT BIOLOGY 2019; 19:180. [PMID: 31054574 PMCID: PMC6500585 DOI: 10.1186/s12870-019-1791-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Accepted: 04/18/2019] [Indexed: 05/10/2023]
Abstract
BACKGROUND The intracellular accommodation of arbuscular mycorrhizal (AM) fungi involves a profound molecular reprogramming of the host cell architecture and metabolism, based on the activation of a symbiotic signaling pathway. In analogy with other plant biotrophs, AM fungi are reported to trigger cell cycle reactivation in their host tissues, possibly in support of the enhanced metabolic demand required for the symbiosis. RESULTS We here compare the efficiency of three Fiji/ImageJ image analysis plugins in localizing and quantifying the increase in nuclear size - a hallmark of recursive events of endoreduplication - in M. truncatula roots colonized by the AM fungus Gigaspora margarita. All three approaches proved to be versatile and upgradeable, allowing the investigation of nuclear changes in a complex tissue; 3D Object Counter provided more detailed information than both TrackMate and Round Surface Detector plugins. On this base we challenged 3D Object Counter with two case studies: verifying the lack of endoreduplication-triggering responses in Medicago truncatula mutants with a known non-symbiotic phenotype; and analysing the correlation in space and time between the induction of cortical cell division and endoreduplication upon AM colonization. Both case studies revealed important biological aspects. Mutant phenotype analyses have demonstrated that the knock-out mutation of different key genes in the symbiotic signaling pathway block AM-associated endoreduplication. Furthermore, our data show that cell divisions occur during initial stages of root colonization and are followed by recursive activation of the endocycle in preparation for arbuscule accommodation. CONCLUSIONS In conclusion, our results indicate 3D Object Counter as the best performing Fiji/ImageJ image analysis script in plant root thick sections and its application highlighted endoreduplication as a major feature of the AM pre-penetration response in root cortical cells.
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Affiliation(s)
- Gennaro Carotenuto
- Department of Life Sciences and Systems Biology, University of Turin, 10125, Torino, Italy
| | - Ivan Sciascia
- Department of Life Sciences and Systems Biology, University of Turin, 10125, Torino, Italy
| | - Ludovica Oddi
- Department of Life Sciences and Systems Biology, University of Turin, 10125, Torino, Italy
| | - Veronica Volpe
- Department of Life Sciences and Systems Biology, University of Turin, 10125, Torino, Italy
| | - Andrea Genre
- Department of Life Sciences and Systems Biology, University of Turin, 10125, Torino, Italy.
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9
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Lotze J, Wolf P, Reinhardt U, Seitz O, Mörl K, Beck-Sickinger AG. Time-Resolved Tracking of Separately Internalized Neuropeptide Y 2 Receptors by Two-Color Pulse-Chase. ACS Chem Biol 2018; 13:618-627. [PMID: 29268018 DOI: 10.1021/acschembio.7b00999] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Internalization and intracellular trafficking of G protein-coupled receptors (GPCR) plays an important role in the signal transduction. These processes are often highly dynamic and take place rapidly. In the past 10 years, it became obvious that internalized GPCRs are also capable of signaling via arrestin or heterotrimeric G proteins within the endosomal compartment. Real-time imaging of receptors in living cells can help to evaluate the temporal and spatial localization. We achieved a two-color pulse-chase labeling approach, which allowed the tracking of the human neuropeptide Y2 receptor (hY2R) in the same cell at different times. The ability to visualize the internalization pathway of two separately labeled and separately stimulated subsets of hY2R in a time-resolved manner revealed a rapid trafficking. Fusion of the two hY2R subsets was already observed 10 min after stimulation in the early endosomal compartment without subsequent separation of the fused receptor populations. The results demonstrate that the cells do not discriminate between receptors that were stimulated and internalized at different time points.
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Affiliation(s)
- Jonathan Lotze
- Institute of Biochemistry, Leipzig University, 04103 Leipzig, Germany
| | - Philipp Wolf
- Institute of Biochemistry, Leipzig University, 04103 Leipzig, Germany
| | - Ulrike Reinhardt
- Institute of Chemistry, Humboldt-University Berlin, 12489 Berlin, Germany
| | - Oliver Seitz
- Institute of Chemistry, Humboldt-University Berlin, 12489 Berlin, Germany
| | - Karin Mörl
- Institute of Biochemistry, Leipzig University, 04103 Leipzig, Germany
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Yoboue ED, Rimessi A, Anelli T, Pinton P, Sitia R. Regulation of Calcium Fluxes by GPX8, a Type-II Transmembrane Peroxidase Enriched at the Mitochondria-Associated Endoplasmic Reticulum Membrane. Antioxid Redox Signal 2017; 27:583-595. [PMID: 28129698 DOI: 10.1089/ars.2016.6866] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
UNLABELLED Glutathione peroxidases (GPXs) are enzymes that are present in almost all organisms with the primary function of limiting peroxide accumulation. In mammals, two of the eight members (GPX7 and GPX8) reside in the endoplasmic reticulum (ER). A peculiar feature of GPX8 is the concomitant presence of a conserved N-terminal transmembrane domain (TMD) and a C-terminal KDEL-like motif for ER localization. AIMS Investigating whether and how GPX8 impacts Ca2+ homeostasis and signaling. RESULTS We show that GPX8 is enriched in mitochondria-associated membranes and regulates Ca2+ storage and fluxes. Its levels correlate with [Ca2+]ER, and cytosolic and mitochondrial Ca2+ fluxes. GPX7, which lacks a TMD, does not share these properties. Deleting or replacing the GPX8 TMD with an unrelated N-terminal membrane integration sequence abolishes all effects on Ca2+ fluxes, whereas appending the GPX8 TMD to GPX7 transfers the Ca2+-regulating properties. Innovation and Conclusion: The notion that the TMD of GPX8, in addition to its enzymatic activity, is essential for regulating Ca2+ dynamics reveals a novel level of integration between redox-related proteins and Ca2+ signaling/homeostasis. Antioxid. Redox Signal. 27, 583-595.
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Affiliation(s)
- Edgar Djaha Yoboue
- 1 Protein Transport and Secretion Unit, Division of Genetics and Cell Biology, IRCCS Ospedale San Raffaele , Milan, Italy
| | - Alessandro Rimessi
- 2 Section of Pathology, Oncology and Experimental Biology, Laboratory for Technologies of Advanced Therapies (LTTA), Department of Morphology, Surgery and Experimental Medicine, University of Ferrara , Ferrara, Italy
| | - Tiziana Anelli
- 1 Protein Transport and Secretion Unit, Division of Genetics and Cell Biology, IRCCS Ospedale San Raffaele , Milan, Italy .,3 Vita-Salute San Raffaele University, School of Medicine, Milan, Italy
| | - Paolo Pinton
- 2 Section of Pathology, Oncology and Experimental Biology, Laboratory for Technologies of Advanced Therapies (LTTA), Department of Morphology, Surgery and Experimental Medicine, University of Ferrara , Ferrara, Italy
| | - Roberto Sitia
- 1 Protein Transport and Secretion Unit, Division of Genetics and Cell Biology, IRCCS Ospedale San Raffaele , Milan, Italy .,3 Vita-Salute San Raffaele University, School of Medicine, Milan, Italy
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11
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Roles of N-glycans in the polymerization-dependent aggregation of mutant Ig-μ chains in the early secretory pathway. Sci Rep 2017; 7:41815. [PMID: 28157181 PMCID: PMC5291101 DOI: 10.1038/srep41815] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Accepted: 12/28/2016] [Indexed: 02/07/2023] Open
Abstract
The polymeric structure of secretory IgM allows efficient antigen binding and complement fixation. The available structural models place the N-glycans bound to asparagines 402 and 563 of Ig-μ chains within a densely packed core of native IgM. These glycans are found in the high mannose state also in secreted IgM, suggesting that polymerization hinders them to Golgi processing enzymes. Their absence alters polymerization. Here we investigate their role following the fate of aggregation-prone mutant μ chains lacking the Cμ1 domain (μ∆). Our data reveal that μ∆ lacking 563 glycans (μ∆5) form larger intracellular aggregates than μ∆ and are not secreted. Like μ∆, they sequester ERGIC-53, a lectin previously shown to promote polymerization. In contrast, μ∆ lacking 402 glycans (μ∆4) remain detergent soluble and accumulate in the ER, as does a double mutant devoid of both (μ∆4–5). These results suggest that the two C-terminal Ig-μ glycans shape the polymerization-dependent aggregation by engaging lectins and acting as spacers in the alignment of individual IgM subunits in native polymers.
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12
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Tinevez JY, Perry N, Schindelin J, Hoopes GM, Reynolds GD, Laplantine E, Bednarek SY, Shorte SL, Eliceiri KW. TrackMate: An open and extensible platform for single-particle tracking. Methods 2016; 115:80-90. [PMID: 27713081 DOI: 10.1016/j.ymeth.2016.09.016] [Citation(s) in RCA: 1701] [Impact Index Per Article: 212.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Revised: 09/29/2016] [Accepted: 09/30/2016] [Indexed: 01/12/2023] Open
Abstract
We present TrackMate, an open source Fiji plugin for the automated, semi-automated, and manual tracking of single-particles. It offers a versatile and modular solution that works out of the box for end users, through a simple and intuitive user interface. It is also easily scriptable and adaptable, operating equally well on 1D over time, 2D over time, 3D over time, or other single and multi-channel image variants. TrackMate provides several visualization and analysis tools that aid in assessing the relevance of results. The utility of TrackMate is further enhanced through its ability to be readily customized to meet specific tracking problems. TrackMate is an extensible platform where developers can easily write their own detection, particle linking, visualization or analysis algorithms within the TrackMate environment. This evolving framework provides researchers with the opportunity to quickly develop and optimize new algorithms based on existing TrackMate modules without the need of having to write de novo user interfaces, including visualization, analysis and exporting tools. The current capabilities of TrackMate are presented in the context of three different biological problems. First, we perform Caenorhabditis-elegans lineage analysis to assess how light-induced damage during imaging impairs its early development. Our TrackMate-based lineage analysis indicates the lack of a cell-specific light-sensitive mechanism. Second, we investigate the recruitment of NEMO (NF-κB essential modulator) clusters in fibroblasts after stimulation by the cytokine IL-1 and show that photodamage can generate artifacts in the shape of TrackMate characterized movements that confuse motility analysis. Finally, we validate the use of TrackMate for quantitative lifetime analysis of clathrin-mediated endocytosis in plant cells.
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Affiliation(s)
| | - Nick Perry
- Imagopole, Citech, Institut Pasteur, 75724 Paris, France
| | - Johannes Schindelin
- Laboratory for Optical and Computational Instrumentation, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Genevieve M Hoopes
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Gregory D Reynolds
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Emmanuel Laplantine
- Laboratory of Signaling and Pathogenesis, Centre National de la Recherche Scientifique, UMR 3691, Institut Pasteur, 75724 Paris, France
| | - Sebastian Y Bednarek
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | | | - Kevin W Eliceiri
- Laboratory for Optical and Computational Instrumentation, University of Wisconsin-Madison, Madison, WI 53706, USA; Morgridge Institute for Research, Madison, WI 53719, USA
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13
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Medraño-Fernandez I, Bestetti S, Bertolotti M, Bienert GP, Bottino C, Laforenza U, Rubartelli A, Sitia R. Stress Regulates Aquaporin-8 Permeability to Impact Cell Growth and Survival. Antioxid Redox Signal 2016; 24:1031-44. [PMID: 26972385 PMCID: PMC4931348 DOI: 10.1089/ars.2016.6636] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
UNLABELLED Aquaporin-8 (AQP8) allows the bidirectional transport of water and hydrogen peroxide across biological membranes. Depending on its concentration, H2O2 exerts opposite roles, amplifying growth factor signaling in physiological conditions, but causing severe cell damage when in excess. Thus, H2O2 permeability is likely to be tightly controlled in living cells. AIMS In this study, we investigated whether and how the transport of H2O2 through plasma membrane AQP8 is regulated, particularly during cell stress. RESULTS We show that diverse cellular stress conditions, including heat, hypoxia, and ER stress, reversibly inhibit the permeability of AQP8 to H2O2 and water. Preventing the accumulation of intracellular reactive oxygen species (ROS) during stress counteracts AQP8 blockade. Once inhibition is established, AQP8-dependent transport can be rescued by reducing agents. Neither H2O2 nor water transport is impaired in stressed cells expressing a mutant AQP8, in which cysteine 53 had been replaced by serine. Cells expressing this mutant are more resistant to stress-, drug-, and radiation-induced growth arrest and death. INNOVATION AND CONCLUSION The control of AQP8-mediated H2O2 transport provides a novel mechanism to regulate cell signaling and survival during stress. Antioxid. Redox Signal. 24, 1031-1044.
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Affiliation(s)
- Iria Medraño-Fernandez
- 1 Protein Transport and Secretion Unit, Division of Genetics and Cell Biology, IRCCS Ospedale San Raffaele/Università Vita-Salute San Raffaele , Milan, Italy
| | - Stefano Bestetti
- 1 Protein Transport and Secretion Unit, Division of Genetics and Cell Biology, IRCCS Ospedale San Raffaele/Università Vita-Salute San Raffaele , Milan, Italy
| | - Milena Bertolotti
- 1 Protein Transport and Secretion Unit, Division of Genetics and Cell Biology, IRCCS Ospedale San Raffaele/Università Vita-Salute San Raffaele , Milan, Italy
| | - Gerd P Bienert
- 2 Metalloid Transport Group, Leibniz Institute of Plant Genetics and Crop Plant Research , Gatersleben, Germany
| | - Cinzia Bottino
- 3 Department of Molecular Medicine, University of Pavia , Pavia, Italy
| | - Umberto Laforenza
- 3 Department of Molecular Medicine, University of Pavia , Pavia, Italy
| | - Anna Rubartelli
- 4 Cell Biology Unit, IRCCS AOU San Martino-IST , Genoa, Italy
| | - Roberto Sitia
- 1 Protein Transport and Secretion Unit, Division of Genetics and Cell Biology, IRCCS Ospedale San Raffaele/Università Vita-Salute San Raffaele , Milan, Italy
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14
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Abstract
Professional secretory cells produce and release abundant proteins. Particularly in case of mutations and/or insufficient chaperoning, these can aggregate and become toxic within or amongst cells. Immunoglobulins (Ig) are no exception. In the extracellular space, certain Ig-L chains form fibrils causing systemic amyloidosis. On the other hand, Ig variants lacking the first constant domain condense in dilated cisternae of the early secretory compartment, called Russell Bodies (RB), frequently observed in plasma cell dyscrasias, autoimmune diseases and chronic infections. RB biogenesis can be recapitulated in lymphoid and non-lymphoid cells by expressing mutant Ig-μ, providing powerful models to investigate the pathophysiology of endoplasmic reticulum storage disorders. Here we analyze the aggregation propensity and the biochemical features of the intra- and extra-cellular Ig deposits in human cells, revealing β-aggregated features for RB.
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Affiliation(s)
- Maria Francesca Mossuto
- Unit of Protein Transport and Secretion, Division of Genetics and Cell Biology, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Diletta Ami
- 1] Department of Physics, University of Milano-Bicocca [2] Department of Biotechnology and Biosciences, University of Milano-Bicocca, Piazza della Scienza 2, Milano, 20126, Italy
| | - Tiziana Anelli
- 1] Unit of Protein Transport and Secretion, Division of Genetics and Cell Biology, IRCCS San Raffaele Scientific Institute, Milan, Italy [2] Vita-Salute San Raffaele University, Milan, Italy
| | - Claudio Fagioli
- Unit of Protein Transport and Secretion, Division of Genetics and Cell Biology, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Silvia Maria Doglia
- 1] Department of Physics, University of Milano-Bicocca [2] Department of Biotechnology and Biosciences, University of Milano-Bicocca, Piazza della Scienza 2, Milano, 20126, Italy
| | - Roberto Sitia
- 1] Unit of Protein Transport and Secretion, Division of Genetics and Cell Biology, IRCCS San Raffaele Scientific Institute, Milan, Italy [2] Vita-Salute San Raffaele University, Milan, Italy
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15
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Abstract
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Exploration of protein function and
interaction is critical for
discovering links among genomics, proteomics, and disease state; yet,
the immense complexity of proteomics found in biological systems currently
limits our investigational capacity. Although affinity and autofluorescent
tags are widely employed for protein analysis, these methods have
been met with limited success because they lack specificity and require
multiple fusion tags and genetic constructs. As an alternative approach,
the innovative HaloTag protein fusion platform allows protein function
and interaction to be comprehensively analyzed using a single genetic
construct with multiple capabilities. This is accomplished using a
simplified process, in which a variable HaloTag ligand binds rapidly
to the HaloTag protein (usually linked to the protein of interest)
with high affinity and specificity. In this review, we examine all
current applications of the HaloTag technology platform for biomedical
applications, such as the study of protein isolation and purification,
protein function, protein–protein and protein–DNA interactions,
biological assays, in vitro cellular imaging, and in vivo molecular imaging. In addition, novel uses of the
HaloTag platform are briefly discussed along with potential future
applications.
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Affiliation(s)
- Christopher G England
- †Department of Medical Physics, University of Wisconsin-Madison, Madison, Wisconsin 53705, United States
| | - Haiming Luo
- ‡Department of Radiology, University of Wisconsin-Madison, Madison, Wisconsin 53705, United States
| | - Weibo Cai
- †Department of Medical Physics, University of Wisconsin-Madison, Madison, Wisconsin 53705, United States.,‡Department of Radiology, University of Wisconsin-Madison, Madison, Wisconsin 53705, United States.,§University of Wisconsin Carbone Cancer Center, Madison, Wisconsin 53705, United States
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