151
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Jung D, Sato K, Min K, Shigenaga A, Jung J, Otaka A, Kwon Y. Photo-triggered fluorescent labelling of recombinant proteins in live cells. Chem Commun (Camb) 2016; 51:9670-3. [PMID: 25977944 DOI: 10.1039/c5cc01067e] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
A method to photo-chemically trigger fluorescent labelling of proteins in live cells is developed. The approach is based on photo-caged split-intein mediated conditional protein trans-splicing reaction and enabled background-free fluorescent labelling of target proteins with the necessary spatiotemporal control.
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Affiliation(s)
- Deokho Jung
- Department of Biomedical Engineering, Dongguk University-Seoul, Pildong 3-ga, Seoul, Korea.
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152
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Abstract
A quiet revolution is under way in technologies used for nanoscale cellular imaging. Focused ion beams, previously restricted to the materials sciences and semiconductor fields, are rapidly becoming powerful tools for ultrastructural imaging of biological samples. Cell and tissue architecture, as preserved in plastic-embedded resin or in plunge-frozen form, can be investigated in three dimensions by scanning electron microscopy imaging of freshly created surfaces that result from the progressive removal of material using a focused ion beam. The focused ion beam can also be used as a sculpting tool to create specific specimen shapes such as lamellae or needles that can be analyzed further by transmission electron microscopy or by methods that probe chemical composition. Here we provide an in-depth primer to the application of focused ion beams in biology, including a guide to the practical aspects of using the technology, as well as selected examples of its contribution to the generation of new insights into subcellular architecture and mechanisms underlying host-pathogen interactions.
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153
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Liv N, van Oosten Slingeland DSB, Baudoin JP, Kruit P, Piston DW, Hoogenboom JP. Electron Microscopy of Living Cells During in Situ Fluorescence Microscopy. ACS NANO 2016; 10:265-73. [PMID: 26580231 PMCID: PMC4729641 DOI: 10.1021/acsnano.5b03970] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
We present an approach toward dynamic nanoimaging: live fluorescence of cells encapsulated in a bionanoreactor is complemented with in situ scanning electron microscopy (SEM) on an integrated microscope. This allows us to take SEM snapshots on-demand, that is, at a specific location in time, at a desired region of interest, guided by the dynamic fluorescence imaging. We show that this approach enables direct visualization, with EM resolution, of the distribution of bioconjugated quantum dots on cellular extensions during uptake and internalization.
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Affiliation(s)
- Nalan Liv
- Department of Imaging Physics, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, The Netherlands
| | | | - Jean-Pierre Baudoin
- Department of Molecular Physiology and Biophysics, Vanderbilt University, 747 Light Hall, Nashville, Tennessee 37232-0615, United States
| | - Pieter Kruit
- Department of Imaging Physics, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, The Netherlands
| | - David W. Piston
- Department of Molecular Physiology and Biophysics, Vanderbilt University, 747 Light Hall, Nashville, Tennessee 37232-0615, United States
| | - Jacob P. Hoogenboom
- Department of Imaging Physics, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, The Netherlands
- Corresponding Author:
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154
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Wüstner D, Lund FW, Röhrl C, Stangl H. Potential of BODIPY-cholesterol for analysis of cholesterol transport and diffusion in living cells. Chem Phys Lipids 2016; 194:12-28. [DOI: 10.1016/j.chemphyslip.2015.08.007] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2015] [Revised: 08/07/2015] [Accepted: 08/12/2015] [Indexed: 01/04/2023]
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155
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SAITO M, IMAI K, KOYAMA M. A Tetracysteine-tag and HeLa Cell System for the Dynamic Analysis of the Localization and Gating Properties of a Specific Connexin Isoform. ELECTROCHEMISTRY 2016. [DOI: 10.5796/electrochemistry.84.299] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
- Mikako SAITO
- Department of Biotechnology and Life Science, Tokyo University of Agriculture and Technology
| | - Keiichi IMAI
- Department of Biotechnology and Life Science, Tokyo University of Agriculture and Technology
| | - Masato KOYAMA
- Department of Biotechnology and Life Science, Tokyo University of Agriculture and Technology
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156
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Kinase programs spatiotemporally regulate gap junction assembly and disassembly: Effects on wound repair. Semin Cell Dev Biol 2015; 50:40-8. [PMID: 26706150 DOI: 10.1016/j.semcdb.2015.12.010] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2015] [Accepted: 12/08/2015] [Indexed: 01/05/2023]
Abstract
Gap junctions are highly ordered plasma membrane domains that are constantly assembled, remodeled and turned over due to the short half-life of connexins, the integral membrane proteins that form gap junctions. Connexin 43 (Cx43), by far the most widely expressed connexin, is phosphorylated at multiple serine residues in the cytoplasmic, C-terminal region allowing for exquisite cellular control over gap junctional communication. This is evident during epidermal wounding where spatiotemporal changes in connexin expression occur as cells are instructed whether to die, proliferate or migrate to promote repair. Early gap junctional communication is required for initiation of keratinocyte migration, but accelerated Cx43 turnover is also critical for proper wound healing at later stages. These events are controlled via a "kinase program" where sequential phosphorylation of Cx43 leads to reductions in Cx43's half-life and significant depletion of gap junctions from the plasma membrane within several hours. The complex regulation of gap junction assembly and turnover affords several steps where intervention might speed wound healing.
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157
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Begemann I, Viplav A, Rasch C, Galic M. Stochastic Micro-Pattern for Automated Correlative Fluorescence - Scanning Electron Microscopy. Sci Rep 2015; 5:17973. [PMID: 26647824 PMCID: PMC4673610 DOI: 10.1038/srep17973] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Accepted: 11/10/2015] [Indexed: 12/01/2022] Open
Abstract
Studies of cellular surface features gain from correlative approaches, where live cell information acquired by fluorescence light microscopy is complemented by ultrastructural information from scanning electron micrographs. Current approaches to spatially align fluorescence images with scanning electron micrographs are technically challenging and often cost or time-intensive. Relying exclusively on open-source software and equipment available in a standard lab, we have developed a method for rapid, software-assisted alignment of fluorescence images with the corresponding scanning electron micrographs via a stochastic gold micro-pattern. Here, we provide detailed instructions for micro-pattern production and image processing, troubleshooting for critical intermediate steps, and examples of membrane ultra-structures aligned with the fluorescence signal of proteins enriched at such sites. Together, the presented method for correlative fluorescence – scanning electron microscopy is versatile, robust and easily integrated into existing workflows, permitting image alignment with accuracy comparable to existing approaches with negligible investment of time or capital.
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Affiliation(s)
- Isabell Begemann
- DFG Cluster of Excellence 'Cells in Motion', (EXC 1003).,Institute of Medical Physics and Biophysics, University of Münster, Germany
| | - Abhiyan Viplav
- DFG Cluster of Excellence 'Cells in Motion', (EXC 1003).,Institute of Medical Physics and Biophysics, University of Münster, Germany
| | - Christiane Rasch
- Institute of Medical Physics and Biophysics, University of Münster, Germany
| | - Milos Galic
- DFG Cluster of Excellence 'Cells in Motion', (EXC 1003).,Institute of Medical Physics and Biophysics, University of Münster, Germany
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158
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Self-labelling enzymes as universal tags for fluorescence microscopy, super-resolution microscopy and electron microscopy. Sci Rep 2015; 5:17740. [PMID: 26643905 PMCID: PMC4672345 DOI: 10.1038/srep17740] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Accepted: 11/04/2015] [Indexed: 11/17/2022] Open
Abstract
Research in cell biology demands advanced microscopy techniques such as confocal fluorescence microscopy (FM), super-resolution microscopy (SRM) and transmission electron microscopy (TEM). Correlative light and electron microscopy (CLEM) is an approach to combine data on the dynamics of proteins or protein complexes in living cells with the ultrastructural details in the low nanometre scale. To correlate both data sets, markers functional in FM, SRM and TEM are required. Genetically encoded markers such as fluorescent proteins or self-labelling enzyme tags allow observations in living cells. Various genetically encoded tags are available for FM and SRM, but only few tags are suitable for CLEM. Here, we describe the red fluorescent dye tetramethylrhodamine (TMR) as a multimodal marker for CLEM. TMR is used as fluorochrome coupled to ligands of genetically encoded self-labelling enzyme tags HaloTag, SNAP-tag and CLIP-tag in FM and SRM. We demonstrate that TMR can additionally photooxidize diaminobenzidine (DAB) to an osmiophilic polymer visible on TEM sections, thus being a marker suitable for FM, SRM and TEM. We evaluated various organelle markers with enzymatic tags in mammalian cells labelled with TMR-coupled ligands and demonstrate the use as efficient and versatile DAB photooxidizer for CLEM approaches.
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159
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Ou HD, Deerinck TJ, Bushong E, Ellisman MH, O'Shea CC. Visualizing viral protein structures in cells using genetic probes for correlated light and electron microscopy. Methods 2015; 90:39-48. [PMID: 26066760 PMCID: PMC4655137 DOI: 10.1016/j.ymeth.2015.06.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Revised: 06/01/2015] [Accepted: 06/02/2015] [Indexed: 01/08/2023] Open
Abstract
Structural studies of viral proteins most often use high-resolution techniques such as X-ray crystallography, nuclear magnetic resonance, single particle negative stain, or cryo-electron microscopy (EM) to reveal atomic interactions of soluble, homogeneous viral proteins or viral protein complexes. Once viral proteins or complexes are separated from their host's cellular environment, their natural in situ structure and details of how they interact with other cellular components may be lost. EM has been an invaluable tool in virology since its introduction in the late 1940's and subsequent application to cells in the 1950's. EM studies have expanded our knowledge of viral entry, viral replication, alteration of cellular components, and viral lysis. Most of these early studies were focused on conspicuous morphological cellular changes, because classic EM metal stains were designed to highlight classes of cellular structures rather than specific molecular structures. Much later, to identify viral proteins inducing specific structural configurations at the cellular level, immunostaining with a primary antibody followed by colloidal gold secondary antibody was employed to mark the location of specific viral proteins. This technique can suffer from artifacts in cellular ultrastructure due to compromises required to provide access to the immuno-reagents. Immunolocalization methods also require the generation of highly specific antibodies, which may not be available for every viral protein. Here we discuss new methods to visualize viral proteins and structures at high resolutions in situ using correlated light and electron microscopy (CLEM). We discuss the use of genetically encoded protein fusions that oxidize diaminobenzidine (DAB) into an osmiophilic polymer that can be visualized by EM. Detailed protocols for applying the genetically encoded photo-oxidizing protein MiniSOG to a viral protein, photo-oxidation of the fusion protein to yield DAB polymer staining, and preparation of photo-oxidized samples for TEM and serial block-face scanning EM (SBEM) for large-scale volume EM data acquisition are also presented. As an example, we discuss the recent multi-scale analysis of Adenoviral protein E4-ORF3 that reveals a new type of multi-functional polymer that disrupts multiple cellular proteins. This new capability to visualize unambiguously specific viral protein structures at high resolutions in the native cellular environment is revealing new insights into how they usurp host proteins and functions to drive pathological viral replication.
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Affiliation(s)
- Horng D Ou
- Molecular and Cell Biology Laboratory, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA; Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Thomas J Deerinck
- National Center for Microscopy and Imaging Research, Center for Research in Biological Systems, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Eric Bushong
- National Center for Microscopy and Imaging Research, Center for Research in Biological Systems, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Mark H Ellisman
- Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA; National Center for Microscopy and Imaging Research, Center for Research in Biological Systems, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA; Department of Neurosciences, University of California at San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Clodagh C O'Shea
- Molecular and Cell Biology Laboratory, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA; Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA.
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160
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Wang HY, Lin YP, Mitchell CK, Ram S, O'Brien J. Two-color fluorescent analysis of connexin 36 turnover: relationship to functional plasticity. J Cell Sci 2015; 128:3888-97. [PMID: 26359298 PMCID: PMC4647165 DOI: 10.1242/jcs.162586] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2014] [Accepted: 09/04/2015] [Indexed: 01/14/2023] Open
Abstract
Gap junctions formed of connexin 36 (Cx36, also known as Gjd2) show tremendous functional plasticity on several time scales. Changes in connexin phosphorylation modify coupling in minutes through an order of magnitude, but recent studies also imply involvement of connexin turnover in regulating cell-cell communication. We utilized Cx36 with an internal HaloTag to study Cx36 turnover and trafficking in cultured cells. Irreversible, covalent pulse-chase labeling with fluorescent HaloTag ligands allowed clear discrimination of newly formed and pre-existing Cx36. Cx36 in junctional plaques turned over with a half-life of 3.1 h, and the turnover rate was unchanged by manipulations of protein kinase A (PKA) activity. In contrast, changes in PKA activity altered coupling within 20 min. New Cx36 in cargo vesicles was added directly to existing gap junctions and newly made Cx36 was not confined to points of addition, but diffused throughout existing gap junctions. Existing connexins also diffused into photobleached areas with a half-time of less than 2 s. In conclusion, studies of Cx36-HaloTag revealed novel features of connexin trafficking and demonstrated that phosphorylation-based changes in coupling occur on a different time scale than turnover.
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Affiliation(s)
- Helen Yanran Wang
- Ruiz Department of Ophthalmology & Visual Science, The University of Texas Health Science Center at Houston, Houston, TX 77030, USA Graduate School of Biomedical Sciences, The University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Ya-Ping Lin
- Ruiz Department of Ophthalmology & Visual Science, The University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Cheryl K Mitchell
- Ruiz Department of Ophthalmology & Visual Science, The University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Sripad Ram
- Carl Zeiss Microscopy LLC, Thornwood, NY 10594, USA
| | - John O'Brien
- Ruiz Department of Ophthalmology & Visual Science, The University of Texas Health Science Center at Houston, Houston, TX 77030, USA Graduate School of Biomedical Sciences, The University of Texas Health Science Center at Houston, Houston, TX 77030, USA
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161
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Bharathi MV, Chhabra M, Paira P. Development of surface immobilized 3-azidocoumarin-based fluorogenic probe via strain promoted click chemistry. Bioorg Med Chem Lett 2015; 25:5737-42. [PMID: 26531149 DOI: 10.1016/j.bmcl.2015.10.078] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Revised: 10/22/2015] [Accepted: 10/26/2015] [Indexed: 12/19/2022]
Abstract
A new class of imaging probe, a fluorogenic version of 1, 3-dipolar cycloaddition of azides and alkynes has been developed. 3-azidocoumarin scaffolds were selectively immobilized on the DBCO modified bead surface via SPAAC and provide direct and strong fluorescence in fluorescence microscopy. This developed click-on beads could be applied to label various biomolecules, such as nucleic acids, proteins and other molecules. To this end, 5'(7-hydroxy 3-azido coumarin) labelled DNA primer also displayed strong fluorescence upon successful immobilization on the bead surface.
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Affiliation(s)
- M Vijaya Bharathi
- Pharmaceutical Chemistry Division, School of Advanced Sciences, VIT University, Vellore 632014, Tamilnadu, India
| | - Mohit Chhabra
- Pharmaceutical Chemistry Division, School of Advanced Sciences, VIT University, Vellore 632014, Tamilnadu, India
| | - Priyankar Paira
- Pharmaceutical Chemistry Division, School of Advanced Sciences, VIT University, Vellore 632014, Tamilnadu, India.
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162
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Basheer W, Shaw R. The "tail" of Connexin43: An unexpected journey from alternative translation to trafficking. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2015; 1863:1848-56. [PMID: 26526689 DOI: 10.1016/j.bbamcr.2015.10.015] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Revised: 10/13/2015] [Accepted: 10/20/2015] [Indexed: 12/23/2022]
Abstract
With each heartbeat, Connexin43 (Cx43) cell-cell communication gap junctions are needed to rapidly spread and coordinate excitation signals for an effective heart contraction. The correct formation and delivery of channels to their respective membrane subdomain is referred to as protein trafficking. Altered Cx43 trafficking is a dangerous complication of diseased myocardium which contributes to the arrhythmias of sudden cardiac death. Cx43 has also been found to regulate many other cellular processes that cannot be explained by cell-cell communication. We recently identified the existence of up to six endogenous internally translated Cx43 N-terminal truncated isoforms from the same full-length mRNA molecule. This is the first evidence that alternative translation is possible for human ion channels and in human heart. Interestingly, we found that these internally translated isoforms, more specifically the 20 kDa isoform (GJA1-20k), is important for delivery of Cx43 to its respective membrane subdomain. This review covers recent advances in Cx43 trafficking and potential importance of alternatively translated Cx43 truncated isoforms. This article is part of a Special Issue entitled: Cardiomyocyte Biology: Integration of Developmental and Environmental Cues in the Heart edited by Marcus Schaub and Hughes Abriel.
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Affiliation(s)
- Wassim Basheer
- Heart Institute and Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Robin Shaw
- Heart Institute and Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, CA, USA; Department of Medicine, University of California Los Angeles, Los Angeles, CA, USA.
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163
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Takizawa T, Powell RD, Hainfeld JF, Robinson JM. FluoroNanogold: an important probe for correlative microscopy. J Chem Biol 2015; 8:129-42. [PMID: 26884817 PMCID: PMC4744603 DOI: 10.1007/s12154-015-0145-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2015] [Accepted: 07/24/2015] [Indexed: 10/23/2022] Open
Abstract
Correlative microscopy is a powerful imaging approach that refers to observing the same exact structures within a specimen by two or more imaging modalities. In biological samples, this typically means examining the same sub-cellular feature with different imaging methods. Correlative microscopy is not restricted to the domains of fluorescence microscopy and electron microscopy; however, currently, most correlative microscopy studies combine these two methods, and in this review, we will focus on the use of fluorescence and electron microscopy. Successful correlative fluorescence and electron microscopy requires probes, or reporter systems, from which useful information can be obtained with each of the imaging modalities employed. The bi-functional immunolabeling reagent, FluoroNanogold, is one such probe that provides robust signals in both fluorescence and electron microscopy. It consists of a gold cluster compound that is visualized by electron microscopy and a covalently attached fluorophore that is visualized by fluorescence microscopy. FluoroNanogold has been an extremely useful labeling reagent in correlative microscopy studies. In this report, we present an overview of research using this unique probe.
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Affiliation(s)
| | - Richard D. Powell
- />Nanoprobes, Incorporated, 95 Horseblock Road, Unit 1, Yaphank, NY 11980-9710 USA
| | - James F. Hainfeld
- />Nanoprobes, Incorporated, 95 Horseblock Road, Unit 1, Yaphank, NY 11980-9710 USA
| | - John M. Robinson
- />Department of Physiology and Cell Biology, Ohio State University, Columbus, OH 43210 USA
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164
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Morphew MK, O'Toole ET, Page CL, Pagratis M, Meehl J, Giddings T, Gardner JM, Ackerson C, Jaspersen SL, Winey M, Hoenger A, McIntosh JR. Metallothionein as a clonable tag for protein localization by electron microscopy of cells. J Microsc 2015; 260:20-9. [PMID: 25974385 PMCID: PMC4573841 DOI: 10.1111/jmi.12262] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2015] [Accepted: 04/07/2015] [Indexed: 11/28/2022]
Abstract
A benign, clonable tag for the localization of proteins by electron microscopy of cells would be valuable, especially if it provided labelling with high signal-to-noise ratio and good spatial resolution. Here we explore the use of metallothionein as such a localization marker. We have achieved good success with desmin labelled in vitro and with a component of the yeast spindle pole body labelled in cells. Heavy metals added after fixation and embedding or during the process of freeze-substitution fixation provide readily visible signals with no concern that the heavy atoms are affecting the behaviour of the protein in its physiological environment. However, our methods did not work with protein components of the nuclear pore complex, suggesting that this approach is not yet universally applicable. We provide a full description of our optimal labelling conditions and other conditions tried, hoping that our work will allow others to label their own proteins of interest and/or improve on the methods we have defined.
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Affiliation(s)
- M K Morphew
- Department of Molecular, Cellular and Developmental, Biology University of Colorado, Boulder, Colorado, 80309-0347, U.S.A
| | - E T O'Toole
- Department of Molecular, Cellular and Developmental, Biology University of Colorado, Boulder, Colorado, 80309-0347, U.S.A
| | - C L Page
- Department of Molecular, Cellular and Developmental, Biology University of Colorado, Boulder, Colorado, 80309-0347, U.S.A
| | - M Pagratis
- Department of Molecular, Cellular and Developmental, Biology University of Colorado, Boulder, Colorado, 80309-0347, U.S.A
| | - J Meehl
- Department of Molecular, Cellular and Developmental, Biology University of Colorado, Boulder, Colorado, 80309-0347, U.S.A
| | - T Giddings
- Department of Molecular, Cellular and Developmental, Biology University of Colorado, Boulder, Colorado, 80309-0347, U.S.A
| | - J M Gardner
- The Stowers Institute for Medical Research, Kansas City, Missouri, 64110 and Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, Kansas, 66160, U.S.A
| | - C Ackerson
- Department of Chemistry, Colorado State University, Fort Collins, Colorado, U.S.A
| | - S L Jaspersen
- The Stowers Institute for Medical Research, Kansas City, Missouri, 64110 and Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, Kansas, 66160, U.S.A
| | - M Winey
- Department of Molecular, Cellular and Developmental, Biology University of Colorado, Boulder, Colorado, 80309-0347, U.S.A
| | - A Hoenger
- Department of Molecular, Cellular and Developmental, Biology University of Colorado, Boulder, Colorado, 80309-0347, U.S.A
| | - J R McIntosh
- Department of Molecular, Cellular and Developmental, Biology University of Colorado, Boulder, Colorado, 80309-0347, U.S.A
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165
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Strickfaden H, Xu ZZ, Hendzel MJ. Visualization of miniSOG Tagged DNA Repair Proteins in Combination with Electron Spectroscopic Imaging (ESI). J Vis Exp 2015. [PMID: 26436332 DOI: 10.3791/52893] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The limits to optical resolution and the challenge of identifying specific protein populations in transmission electron microscopy have been obstacles in cell biology. Many phenomena cannot be explained by in vitro analysis in simplified systems and need additional structural information in situ, particularly in the range between 1 nm and 0.1 µm, in order to be fully understood. Here, electron spectroscopic imaging, a transmission electron microscopy technique that allows simultaneous mapping of the distribution of proteins and nucleic acids, and an expression tag, miniSOG, are combined to study the structure and organization of DNA double-strand break repair foci.
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Affiliation(s)
- Hilmar Strickfaden
- Department of Oncology, Faculty of Dentistry and Medicine, University of Alberta;
| | - Zhi Zhong Xu
- Department of Oncology, Faculty of Dentistry and Medicine, University of Alberta
| | - Michael J Hendzel
- Department of Oncology, Faculty of Dentistry and Medicine, University of Alberta
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166
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Sobala LF, Wang Y, Adler PN. ChtVis-Tomato, a genetic reporter for in vivo visualization of chitin deposition in Drosophila. Development 2015; 142:3974-81. [PMID: 26395478 DOI: 10.1242/dev.126987] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Accepted: 09/08/2015] [Indexed: 01/06/2023]
Abstract
Chitin is a polymer of N-acetylglucosamine that is abundant and widely found in the biological world. It is an important constituent of the cuticular exoskeleton that plays a key role in the insect life cycle. To date, the study of chitin deposition during cuticle formation has been limited by the lack of a method to detect it in living organisms. To overcome this limitation, we have developed ChtVis-Tomato, an in vivo reporter for chitin in Drosophila. ChtVis-Tomato encodes a fusion protein that contains an apical secretion signal, a chitin-binding domain (CBD), a fluorescent protein and a cleavage site to release it from the plasma membrane. The chitin reporter allowed us to study chitin deposition in time lapse experiments and by using it we have identified unexpected deposits of chitin fibers in Drosophila pupae. ChtVis-Tomato should facilitate future studies on chitin in Drosophila and other insects.
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Affiliation(s)
- Lukasz F Sobala
- Biology Department and Cell Biology Department, University of Virginia, Charlottesville, VA 22904, USA
| | - Ying Wang
- Biology Department and Cell Biology Department, University of Virginia, Charlottesville, VA 22904, USA
| | - Paul N Adler
- Biology Department and Cell Biology Department, University of Virginia, Charlottesville, VA 22904, USA
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167
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Intracellular Cleavage of the Cx43 C-Terminal Domain by Matrix-Metalloproteases: A Novel Contributor to Inflammation? Mediators Inflamm 2015; 2015:257471. [PMID: 26424967 PMCID: PMC4573893 DOI: 10.1155/2015/257471] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2015] [Accepted: 08/13/2015] [Indexed: 01/11/2023] Open
Abstract
The coordination of tissue function is mediated by gap junctions (GJs) that enable direct cell-cell transfer of metabolic and electric signals. GJs are formed by connexin (Cx) proteins of which Cx43 is most widespread in the human body. Beyond its role in direct intercellular communication, Cx43 also forms nonjunctional hemichannels (HCs) in the plasma membrane that mediate the release of paracrine signaling molecules in the extracellular environment. Both HC and GJ channel function are regulated by protein-protein interactions and posttranslational modifications that predominantly take place in the C-terminal domain of Cx43. Matrix metalloproteases (MMPs) are a major group of zinc-dependent proteases, known to regulate not only extracellular matrix remodeling, but also processing of intracellular proteins. Together with Cx43 channels, both GJs and HCs, MMPs contribute to acute inflammation and a small number of studies reports on an MMP-Cx43 link. Here, we build further on these reports and present a novel hypothesis that describes proteolytic cleavage of the Cx43 C-terminal domain by MMPs and explores possibilities of how such cleavage events may affect Cx43 channel function. Finally, we set out how aberrant channel function resulting from cleavage can contribute to the acute inflammatory response during tissue injury.
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168
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Loussert Fonta C, Humbel BM. Correlative microscopy. Arch Biochem Biophys 2015; 581:98-110. [DOI: 10.1016/j.abb.2015.05.017] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Revised: 05/26/2015] [Accepted: 05/29/2015] [Indexed: 11/15/2022]
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169
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de Boer P, Hoogenboom JP, Giepmans BNG. Correlated light and electron microscopy: ultrastructure lights up! Nat Methods 2015; 12:503-13. [PMID: 26020503 DOI: 10.1038/nmeth.3400] [Citation(s) in RCA: 303] [Impact Index Per Article: 33.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2014] [Accepted: 04/15/2015] [Indexed: 12/15/2022]
Abstract
Microscopy has gone hand in hand with the study of living systems since van Leeuwenhoek observed living microorganisms and cells in 1674 using his light microscope. A spectrum of dyes and probes now enable the localization of molecules of interest within living cells by fluorescence microscopy. With electron microscopy (EM), cellular ultrastructure has been revealed. Bridging these two modalities, correlated light microscopy and EM (CLEM) opens new avenues. Studies of protein dynamics with fluorescent proteins (FPs), which leave the investigator 'in the dark' concerning cellular context, can be followed by EM examination. Rare events can be preselected at the light microscopy level before EM analysis. Ongoing development-including of dedicated probes, integrated microscopes, large-scale and three-dimensional EM and super-resolution fluorescence microscopy-now paves the way for broad CLEM implementation in biology.
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Affiliation(s)
- Pascal de Boer
- Department of Cell Biology, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands
| | - Jacob P Hoogenboom
- Faculty of Applied Sciences, Delft University of Technology, Delft, the Netherlands
| | - Ben N G Giepmans
- Department of Cell Biology, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands
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170
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Activation of Group I and Group II Metabotropic Glutamate Receptors Causes LTD and LTP of Electrical Synapses in the Rat Thalamic Reticular Nucleus. J Neurosci 2015; 35:7616-25. [PMID: 25972185 DOI: 10.1523/jneurosci.3688-14.2015] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Compared with the extensive characterization of chemical synaptic plasticity, electrical synaptic plasticity remains poorly understood. Electrical synapses are strong and prevalent among the GABAergic neurons of the rodent thalamic reticular nucleus. Using paired whole-cell recordings, we show that activation of Group I metabotropic glutamate receptors (mGluRs) induces long-term depression of electrical synapses. Conversely, activation of the Group II mGluR, mGluR3, induces long-term potentiation of electrical synapses. By testing downstream targets, we show that modifications induced by both mGluR groups converge on the same signaling cascade--adenylyl cyclase to cAMP to protein kinase A--but with opposing effects. Furthermore, the magnitude of modification is inversely correlated to baseline coupling strength. Thus, electrical synapses, like their chemical counterparts, undergo both strengthening and weakening forms of plasticity, which should play a significant role in thalamocortical function.
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171
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Tang W, Tam JHK, Seah C, Chiu J, Tyrer A, Cregan SP, Meakin SO, Pasternak SH. Arf6 controls beta-amyloid production by regulating macropinocytosis of the Amyloid Precursor Protein to lysosomes. Mol Brain 2015; 8:41. [PMID: 26170135 PMCID: PMC4501290 DOI: 10.1186/s13041-015-0129-7] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Accepted: 06/11/2015] [Indexed: 11/15/2022] Open
Abstract
Alzheimer’s disease (AD) is characterized by the deposition of Beta-Amyloid (Aβ) peptides in the brain. Aβ peptides are generated by cleavage of the Amyloid Precursor Protein (APP) by the β − and γ − secretase enzymes. Although this process is tightly linked to the internalization of cell surface APP, the compartments responsible are not well defined. We have found that APP can be rapidly internalized from the cell surface to lysosomes, bypassing early and late endosomes. Here we show by confocal microscopy and electron microscopy that this pathway is mediated by macropinocytosis. APP internalization is enhanced by antibody binding/crosslinking of APP suggesting that APP may function as a receptor. Furthermore, a dominant negative mutant of Arf6 blocks direct transport of APP to lysosomes, but does not affect classical endocytosis to endosomes. Arf6 expression increases through the hippocampus with the development of Alzheimer’s disease, being expressed mostly in the CA1 and CA2 regions in normal individuals but spreading through the CA3 and CA4 regions in individuals with pathologically diagnosed AD. Disruption of lysosomal transport of APP reduces both Aβ40 and Aβ42 production by more than 30 %. Our findings suggest that the lysosome is an important site for Aβ production and that altering APP trafficking represents a viable strategy to reduce Aβ production.
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Affiliation(s)
- Weihao Tang
- J. Allyn Taylor Centre for Cell Biology, Molecular Medicine Research Group, Robarts Research Institute, 1151 Richmond St, London, ON, N6A 5B8, Canada. .,Department of Physiology and Pharmacology, Schulich School of Medicine, the University of Western Ontario, London, ON, N6A 5B7, Canada.
| | - Joshua H K Tam
- J. Allyn Taylor Centre for Cell Biology, Molecular Medicine Research Group, Robarts Research Institute, 1151 Richmond St, London, ON, N6A 5B8, Canada. .,Department of Physiology and Pharmacology, Schulich School of Medicine, the University of Western Ontario, London, ON, N6A 5B7, Canada.
| | - Claudia Seah
- J. Allyn Taylor Centre for Cell Biology, Molecular Medicine Research Group, Robarts Research Institute, 1151 Richmond St, London, ON, N6A 5B8, Canada.
| | - Justin Chiu
- J. Allyn Taylor Centre for Cell Biology, Molecular Medicine Research Group, Robarts Research Institute, 1151 Richmond St, London, ON, N6A 5B8, Canada. .,Department of Physiology and Pharmacology, Schulich School of Medicine, the University of Western Ontario, London, ON, N6A 5B7, Canada.
| | - Andrea Tyrer
- J. Allyn Taylor Centre for Cell Biology, Molecular Medicine Research Group, Robarts Research Institute, 1151 Richmond St, London, ON, N6A 5B8, Canada. .,Department of Physiology and Pharmacology, Schulich School of Medicine, the University of Western Ontario, London, ON, N6A 5B7, Canada.
| | - Sean P Cregan
- J. Allyn Taylor Centre for Cell Biology, Molecular Medicine Research Group, Robarts Research Institute, 1151 Richmond St, London, ON, N6A 5B8, Canada. .,Department of Physiology and Pharmacology, Schulich School of Medicine, the University of Western Ontario, London, ON, N6A 5B7, Canada.
| | - Susan O Meakin
- J. Allyn Taylor Centre for Cell Biology, Molecular Medicine Research Group, Robarts Research Institute, 1151 Richmond St, London, ON, N6A 5B8, Canada. .,Department of Biochemistry, Schulich School of Medicine, the University of Western Ontario, London, ON, N6A 5B7, Canada.
| | - Stephen H Pasternak
- J. Allyn Taylor Centre for Cell Biology, Molecular Medicine Research Group, Robarts Research Institute, 1151 Richmond St, London, ON, N6A 5B8, Canada. .,Department of Clinical Neurological Sciences, Schulich School of Medicine, the University of Western Ontario, London, ON, N6A 5B7, Canada. .,Department of Physiology and Pharmacology, Schulich School of Medicine, the University of Western Ontario, London, ON, N6A 5B7, Canada.
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172
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Xie HY, Cui Y, Deng F, Feng JC. Connexin: a potential novel target for protecting the central nervous system? Neural Regen Res 2015; 10:659-66. [PMID: 26170830 PMCID: PMC4424762 DOI: 10.4103/1673-5374.155444] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/20/2014] [Indexed: 01/11/2023] Open
Abstract
Connexin subunits are proteins that form gap junction channels, and play an important role in communication between adjacent cells. This review article discusses the function of connexins/hemichannels/gap junctions under physiological conditions, and summarizes the findings regarding the role of connexins/hemichannels/gap junctions in the physiological and pathological mechanisms underlying central nervous system diseases such as brain ischemia, traumatic brain and spinal cord injury, epilepsy, brain and spinal cord tumor, migraine, neuroautoimmune disease, Alzheimer's disease, Parkinson's disease, X-linked Charcot-Marie-Tooth disease, Pelizaeus-Merzbacher-like disease, spastic paraplegia and maxillofacial dysplasia. Connexins are considered to be a potential novel target for protecting the central nervous system.
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Affiliation(s)
- Hong-Yan Xie
- Departmet of Neurology, the First Hospital of Jilin University, Changchun, Jilin Province, China
| | - Yu Cui
- Department of Neurosurgery, the First People's Hospital of Xianyang, Xianyang, Shaanxi Province, China
| | - Fang Deng
- Departmet of Neurology, the First Hospital of Jilin University, Changchun, Jilin Province, China
| | - Jia-Chun Feng
- Departmet of Neurology, the First Hospital of Jilin University, Changchun, Jilin Province, China
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173
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Nimlamool W, Andrews RMK, Falk MM. Connexin43 phosphorylation by PKC and MAPK signals VEGF-mediated gap junction internalization. Mol Biol Cell 2015; 26:2755-68. [PMID: 26063728 PMCID: PMC4571336 DOI: 10.1091/mbc.e14-06-1105] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2014] [Accepted: 06/05/2015] [Indexed: 11/16/2022] Open
Abstract
Phosphorylation on well-recognized, regulatory connexin43 amino acid residues by a series of kinases serves as an early molecular signal that triggers not only inhibition of gap junction (GJ)–mediated cell-to-cell communication but also GJ internalization. The findings contribute to the newly evolving dynamic picture of GJs. Gap junctions (GJs) exhibit a complex modus of assembly and degradation to maintain balanced intercellular communication (GJIC). Several growth factors, including vascular endothelial growth factor (VEGF), have been reported to disrupt cell–cell junctions and abolish GJIC. VEGF directly stimulates VEGF-receptor tyrosine kinases on endothelial cell surfaces. Exposing primary porcine pulmonary artery endothelial cells (PAECs) to VEGF for 15 min resulted in a rapid and almost complete loss of connexin43 (Cx43) GJs at cell–cell appositions and a concomitant increase in cytoplasmic, vesicular Cx43. After prolonged incubation periods (60 min), Cx43 GJs reformed and intracellular Cx43 were restored to levels observed before treatment. GJ internalization correlated with efficient inhibition of GJIC, up to 2.8-fold increased phosphorylation of Cx43 serine residues 255, 262, 279/282, and 368, and appeared to be clathrin driven. Phosphorylation of serines 255, 262, and 279/282 was mediated by MAPK, whereas serine 368 phosphorylation was mediated by PKC. Pharmacological inhibition of both signaling pathways significantly reduced Cx43 phosphorylation and GJ internalization. Together, our results indicate that growth factors such as VEGF activate a hierarchical kinase program—including PKC and MAPK—that induces GJ internalization via phosphorylation of well-known regulatory amino acid residues located in the Cx43 C-terminal tail.
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Affiliation(s)
- Wutigri Nimlamool
- Department of Biological Sciences, Lehigh University, Bethlehem, PA 18015
| | | | - Matthias M Falk
- Department of Biological Sciences, Lehigh University, Bethlehem, PA 18015
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174
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Connexin 43 ubiquitination determines the fate of gap junctions: restrict to survive. Biochem Soc Trans 2015; 43:471-5. [DOI: 10.1042/bst20150036] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Connexins (Cxs) are transmembrane proteins that form channels which allow direct intercellular communication (IC) between neighbouring cells via gap junctions. Mechanisms that modulate the amount of channels at the plasma membrane have emerged as important regulators of IC and their de-regulation has been associated with various diseases. Although Cx-mediated IC can be modulated by different mechanisms, ubiquitination has been described as one of the major post-translational modifications involved in Cx regulation and consequently IC. In this review, we focus on the role of ubiquitin and its effect on gap junction intercellular communication.
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175
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Retamal MA, León-Paravic CG, Ezquer M, Ezquer F, Rio RD, Pupo A, Martínez AD, González C. Carbon monoxide: A new player in the redox regulation of connexin hemichannels. IUBMB Life 2015; 67:428-37. [DOI: 10.1002/iub.1388] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Accepted: 05/05/2015] [Indexed: 01/23/2023]
Affiliation(s)
- Mauricio A. Retamal
- Centro de Fisiología Celular e Integrativa, Facultad de Medicina; Clínica Alemana Universidad del Desarrollo; Santiago Chile
| | - Carmen G. León-Paravic
- Centro de Fisiología Celular e Integrativa, Facultad de Medicina; Clínica Alemana Universidad del Desarrollo; Santiago Chile
| | - Marcelo Ezquer
- Centro de Medicina Regenerativa, Facultad de Medicina; Clínica Alemana Universidad del Desarrollo; Santiago Chile
| | - Fernando Ezquer
- Centro de Medicina Regenerativa, Facultad de Medicina; Clínica Alemana Universidad del Desarrollo; Santiago Chile
| | - Rodrigo Del Rio
- Centro de Investigación Biomédica; Universidad Autónoma de Chile; Santiago Chile
| | - Amaury Pupo
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias; Instituto de Neurociencia; Universidad de Valparaíso; Valparaíso Chile
| | - Agustín D. Martínez
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias; Instituto de Neurociencia; Universidad de Valparaíso; Valparaíso Chile
| | - Carlos González
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias; Instituto de Neurociencia; Universidad de Valparaíso; Valparaíso Chile
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176
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Advances in molecular probe-based labeling tools and their application to multiscale multimodal correlated microscopies. J Chem Biol 2015. [DOI: 10.1007/s12154-015-0132-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
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177
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Zhong WQ, Chen G, Zhang W, Xiong XP, Ren JG, Zhao Y, Liu B, Zhao YF. Down-regulation of connexin43 and connexin32 in keratocystic odontogenic tumours: potential association with clinical features. Histopathology 2015; 66:798-807. [PMID: 25270527 DOI: 10.1111/his.12569] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2014] [Accepted: 09/26/2014] [Indexed: 01/08/2023]
Abstract
AIMS The objective of this study was to explore the potential involvement of connexin43 (Cx43) and connexin32 (Cx32), two vital members of the connexin families, in the pathogenesis of keratocystic odontogenic tumours (KCOT). METHODS AND RESULTS The expression levels of Cx43 and Cx32 in human KCOT and normal oral mucosa (OM) tissues were measured using immunohistochemistry and real-time quantitative polymerase chain reaction (qPCR). The relationship between Cx43 and Cx32 expression and markers of proliferation [proliferating cell nuclear antigen (PCNA), cyclin D1], anti-apoptosis [B cell lymphoma 2 (Bcl-2)] and autophagy [light chain 3 (LC3), Sequestosome 1 p62 (p62)] was then investigated in the KCOT samples. The results showed that Cx43 and Cx32 expression was down-regulated significantly in KCOT samples relative to OM samples. Meanwhile, the expression levels of Cx43 and Cx32 were correlated negatively with the expression levels of PCNA, cyclin D1, Bcl-2, LC3 and p62, as confirmed further by double-labelling immunofluorescence analyses. CONCLUSIONS This study reveals for the first time that Cx43 and Cx32 are down-regulated in KCOT and suggests an association with growth regulation, anti-apoptosis and autophagy in KCOT.
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Affiliation(s)
- Wen-Qun Zhong
- State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) and Key Laboratory of Oral Biomedicine Ministry of Education, School and Hospital of Stomatology, Wuhan University, Wuhan, China
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178
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Hayashi T, Yasueda Y, Tamura T, Takaoka Y, Hamachi I. Analysis of Cell-Surface Receptor Dynamics through Covalent Labeling by Catalyst-Tethered Antibody. J Am Chem Soc 2015; 137:5372-80. [DOI: 10.1021/jacs.5b02867] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Takahiro Hayashi
- Department
of Synthetic Chemistry and Biological Chemistry, Graduate School of
Engineering, Kyoto University, Katsura, Kyoto 615-8510, Japan
| | - Yuki Yasueda
- Department
of Synthetic Chemistry and Biological Chemistry, Graduate School of
Engineering, Kyoto University, Katsura, Kyoto 615-8510, Japan
| | - Tomonori Tamura
- Department
of Synthetic Chemistry and Biological Chemistry, Graduate School of
Engineering, Kyoto University, Katsura, Kyoto 615-8510, Japan
| | - Yousuke Takaoka
- Department
of Synthetic Chemistry and Biological Chemistry, Graduate School of
Engineering, Kyoto University, Katsura, Kyoto 615-8510, Japan
| | - Itaru Hamachi
- Department
of Synthetic Chemistry and Biological Chemistry, Graduate School of
Engineering, Kyoto University, Katsura, Kyoto 615-8510, Japan
- Core
Research for Evolutional Science and Technology, Japan Science and Technology Agency, 5 Sanbancho, Chiyoda-ku, Tokyo 102-0075, Japan
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179
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Kim D, Deerinck TJ, Sigal YM, Babcock HP, Ellisman MH, Zhuang X. Correlative stochastic optical reconstruction microscopy and electron microscopy. PLoS One 2015; 10:e0124581. [PMID: 25874453 PMCID: PMC4398493 DOI: 10.1371/journal.pone.0124581] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Accepted: 03/03/2015] [Indexed: 01/19/2023] Open
Abstract
Correlative fluorescence light microscopy and electron microscopy allows the imaging of spatial distributions of specific biomolecules in the context of cellular ultrastructure. Recent development of super-resolution fluorescence microscopy allows the location of molecules to be determined with nanometer-scale spatial resolution. However, correlative super-resolution fluorescence microscopy and electron microscopy (EM) still remains challenging because the optimal specimen preparation and imaging conditions for super-resolution fluorescence microscopy and EM are often not compatible. Here, we have developed several experiment protocols for correlative stochastic optical reconstruction microscopy (STORM) and EM methods, both for un-embedded samples by applying EM-specific sample preparations after STORM imaging and for embedded and sectioned samples by optimizing the fluorescence under EM fixation, staining and embedding conditions. We demonstrated these methods using a variety of cellular targets.
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Affiliation(s)
- Doory Kim
- Howard Hughes Medical Institute, Cambridge, Massachusetts, United States of America
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts, United States of America
| | - Thomas J. Deerinck
- National Center for Microscopy and Imaging Research, Center for Research in Biological Systems, Department of Neurosciences, University of California San Diego, La Jolla, California, United States of America
| | - Yaron M. Sigal
- Howard Hughes Medical Institute, Cambridge, Massachusetts, United States of America
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts, United States of America
| | - Hazen P. Babcock
- Center for Brain Science, Harvard University, Cambridge, Massachusetts, United States of America
| | - Mark H. Ellisman
- National Center for Microscopy and Imaging Research, Center for Research in Biological Systems, Department of Neurosciences, University of California San Diego, La Jolla, California, United States of America
| | - Xiaowei Zhuang
- Howard Hughes Medical Institute, Cambridge, Massachusetts, United States of America
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts, United States of America
- Center for Brain Science, Harvard University, Cambridge, Massachusetts, United States of America
- Department of Physics, Harvard University, Cambridge, Massachusetts, United States of America
- * E-mail:
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180
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Yan Q, Bruchez MP. Advances in chemical labeling of proteins in living cells. Cell Tissue Res 2015; 360:179-94. [PMID: 25743694 PMCID: PMC4380784 DOI: 10.1007/s00441-015-2145-4] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2015] [Accepted: 02/02/2015] [Indexed: 01/07/2023]
Abstract
The pursuit of quantitative biological information via imaging requires robust labeling approaches that can be used in multiple applications and with a variety of detectable colors and properties. In addition to conventional fluorescent proteins, chemists and biologists have come together to provide a range of approaches that combine dye chemistry with the convenience of genetic targeting. This hybrid-tagging approach amalgamates the rational design of properties available through synthetic dye chemistry with the robust biological targeting available with genetic encoding. In this review, we discuss the current range of approaches that have been exploited for dye targeting or for targeting and activation and some of the recent applications that are uniquely permitted by these hybrid-tagging approaches.
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Affiliation(s)
- Qi Yan
- Sharp Edge Laboratories, Inc. Pittsburgh, PA
| | - Marcel P. Bruchez
- Sharp Edge Laboratories, Inc. Pittsburgh, PA
- Molecular Biosensor and Imaging Center, Carnegie Mellon University, Pittsburgh, PA
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, PA
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA
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181
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Takaoka Y, Nishikawa Y, Hashimoto Y, Sasaki K, Hamachi I. Ligand-directed dibromophenyl benzoate chemistry for rapid and selective acylation of intracellular natural proteins. Chem Sci 2015; 6:3217-3224. [PMID: 28706692 PMCID: PMC5490417 DOI: 10.1039/c5sc00190k] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2015] [Accepted: 03/20/2015] [Indexed: 12/28/2022] Open
Abstract
A rapid and selective protein labeling method, LDBB chemistry is a useful tool for natural protein imaging in living cells.
A rapid and selective ligand-directed chemical reaction was developed for the acylation of proteins in living cells on the basis of ligand-directed chemistry. By fine tuning the reactivity and stability of the phenyl ester derivatives, we successfully identified ortho-dibromophenyl benzoate as the optimal reactive motif. It was sufficiently stable in an aqueous buffer, hydrolyzing less than 10% after 13 h of incubation, but reactive enough for efficient and selective protein labeling in living mammalian cells, as well as in vitro (referred to as ligand-directed dibromophenyl benzoate (LDBB) chemistry). Using this chemistry, various fluorophores can be tethered to the target protein directly, which allows fluorescence visualization of the labeled protein in live cells using different colored fluorophore groups (including coumarin, fluorescein and rhodamine). Furthermore, this labeling is applicable to not only an overexpressed protein (E. coli dihydrofolate reductase) but also endogenous human carbonic anhydrase II and XII under living cell conditions. LDBB chemistry is a new entry of ligand-directed protein labeling methods, and should be particularly useful for the imaging of natural proteins in living cells.
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Affiliation(s)
- Yousuke Takaoka
- Department of Synthetic Chemistry and Biological Chemistry , Graduate School of Engineering Kyoto University , Katsura , Kyoto 615-8510 , Japan . ; ; Tel: +81-22-795-6557
| | - Yuki Nishikawa
- Department of Synthetic Chemistry and Biological Chemistry , Graduate School of Engineering Kyoto University , Katsura , Kyoto 615-8510 , Japan . ; ; Tel: +81-22-795-6557
| | - Yuki Hashimoto
- Department of Synthetic Chemistry and Biological Chemistry , Graduate School of Engineering Kyoto University , Katsura , Kyoto 615-8510 , Japan . ; ; Tel: +81-22-795-6557
| | - Kenta Sasaki
- Department of Synthetic Chemistry and Biological Chemistry , Graduate School of Engineering Kyoto University , Katsura , Kyoto 615-8510 , Japan . ; ; Tel: +81-22-795-6557
| | - Itaru Hamachi
- Department of Synthetic Chemistry and Biological Chemistry , Graduate School of Engineering Kyoto University , Katsura , Kyoto 615-8510 , Japan . ; ; Tel: +81-22-795-6557.,Core Research for Evolutional Science and Technology (CREST) , Japan Science and Technology Agency , 5 Sanbancho , Chiyoda-ku , Tokyo 102-0075 , Japan
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182
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Kuipers J, van Ham TJ, Kalicharan RD, Veenstra-Algra A, Sjollema KA, Dijk F, Schnell U, Giepmans BNG. FLIPPER, a combinatorial probe for correlated live imaging and electron microscopy, allows identification and quantitative analysis of various cells and organelles. Cell Tissue Res 2015; 360:61-70. [PMID: 25786736 PMCID: PMC4379394 DOI: 10.1007/s00441-015-2142-7] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Accepted: 01/30/2015] [Indexed: 11/25/2022]
Abstract
Ultrastructural examination of cells and tissues by electron microscopy (EM) yields detailed information on subcellular structures. However, EM is typically restricted to small fields of view at high magnification; this makes quantifying events in multiple large-area sample sections extremely difficult. Even when combining light microscopy (LM) with EM (correlated LM and EM: CLEM) to find areas of interest, the labeling of molecules is still a challenge. We present a new genetically encoded probe for CLEM, named "FLIPPER", which facilitates quantitative analysis of ultrastructural features in cells. FLIPPER consists of a fluorescent protein (cyan, green, orange, or red) for LM visualization, fused to a peroxidase allowing visualization of targets at the EM level. The use of FLIPPER is straightforward and because the module is completely genetically encoded, cells can be optimally prepared for EM examination. We use FLIPPER to quantify cellular morphology at the EM level in cells expressing a normal and disease-causing point-mutant cell-surface protein called EpCAM (epithelial cell adhesion molecule). The mutant protein is retained in the endoplasmic reticulum (ER) and could therefore alter ER function and morphology. To reveal possible ER alterations, cells were co-transfected with color-coded full-length or mutant EpCAM and a FLIPPER targeted to the ER. CLEM examination of the mixed cell population allowed color-based cell identification, followed by an unbiased quantitative analysis of the ER ultrastructure by EM. Thus, FLIPPER combines bright fluorescent proteins optimized for live imaging with high sensitivity for EM labeling, thereby representing a promising tool for CLEM.
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Affiliation(s)
- Jeroen Kuipers
- Department of Cell Biology, University Medical Center Groningen, University of Groningen, A. Deusinglaan 1, 9713 AV Groningen, The Netherlands
| | - Tjakko J. van Ham
- Present Address: Department of Clinical Genetics, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Ruby D. Kalicharan
- Department of Cell Biology, University Medical Center Groningen, University of Groningen, A. Deusinglaan 1, 9713 AV Groningen, The Netherlands
| | - Anneke Veenstra-Algra
- Department of Cell Biology, University Medical Center Groningen, University of Groningen, A. Deusinglaan 1, 9713 AV Groningen, The Netherlands
| | - Klaas A. Sjollema
- Department of Cell Biology, University Medical Center Groningen, University of Groningen, A. Deusinglaan 1, 9713 AV Groningen, The Netherlands
| | - Freark Dijk
- Department of Cell Biology, University Medical Center Groningen, University of Groningen, A. Deusinglaan 1, 9713 AV Groningen, The Netherlands
| | - Ulrike Schnell
- Present Address: Department of Internal Medicine (Nephrology), University of Texas Southwestern Medical Center, Dallas, Tex. USA
| | - Ben N. G. Giepmans
- Department of Cell Biology, University Medical Center Groningen, University of Groningen, A. Deusinglaan 1, 9713 AV Groningen, The Netherlands
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183
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Zhu X, Zhang L, Kao YT, Xu F, Min W. A tunable fluorescent timer method for imaging spatial-temporal protein dynamics using light-driven photoconvertible protein. JOURNAL OF BIOPHOTONICS 2015; 8:226-232. [PMID: 24488612 DOI: 10.1002/jbio.201300174] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2013] [Revised: 12/10/2013] [Accepted: 01/07/2014] [Indexed: 06/03/2023]
Abstract
Cellular function is largely determined by protein behaviors occurring in both space and time. While regular fluorescent proteins can only report spatial locations of the target inside cells, fluorescent timers have emerged as an invaluable tool for revealing coupled spatial-temporal protein dynamics. Existing fluorescent timers are all based on chemical maturation. Herein we propose a light-driven timer concept that could report relative protein ages at specific sub-cellular locations, by weakly but chronically illuminating photoconvertible fluorescent proteins inside cells. This new method exploits light, instead of oxygen, as the driving force. Therefore its timing speed is optically tunable by adjusting the photoconverting laser intensity. We characterized this light-driven timer method both in vitro and in vivo and applied it to image spatiotemporal distributions of several proteins with different lifetimes. This novel timer method thus offers a flexible "ruler" for studying temporal hierarchy of spatially ordered processes with exquisite spatial-temporal resolution.
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Affiliation(s)
- Xinxin Zhu
- Department of Chemistry, Columbia University, New York, NY 10027, USA
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184
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Venkatagopalan P, Daskalova SM, Lopez LA, Dolezal KA, Hogue BG. Coronavirus envelope (E) protein remains at the site of assembly. Virology 2015; 478:75-85. [PMID: 25726972 PMCID: PMC4550588 DOI: 10.1016/j.virol.2015.02.005] [Citation(s) in RCA: 138] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2014] [Revised: 09/19/2014] [Accepted: 02/04/2015] [Indexed: 01/01/2023]
Abstract
Coronaviruses (CoVs) assemble at endoplasmic reticulum Golgi intermediate compartment (ERGIC) membranes and egress from cells in cargo vesicles. Only a few molecules of the envelope (E) protein are assembled into virions. The role of E in morphogenesis is not fully understood. The cellular localization and dynamics of mouse hepatitis CoV A59 (MHV) E protein were investigated to further understanding of its role during infection. E protein localized in the ERGIC and Golgi with the amino and carboxy termini in the lumen and cytoplasm, respectively. E protein does not traffic to the cell surface. MHV was genetically engineered with a tetracysteine tag at the carboxy end of E. Fluorescence recovery after photobleaching (FRAP) showed that E is mobile in ERGIC/Golgi membranes. Correlative light electron microscopy (CLEM) confirmed the presence of E in Golgi cisternae. The results provide strong support that E proteins carry out their function(s) at the site of budding/assembly. Mouse hepatitis coronavirus (MHV-CoV) E protein localizes in the ERGIC and Golgi. MHV-CoV E does not transport to the cell surface. MHV-CoV can be genetically engineered with a tetracysteine tag appended to E. First FRAP and correlative light electron microscopy of a CoV E protein. Live-cell imaging shows that E is mobile in ERGIC/Golgi membranes.
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Affiliation(s)
- Pavithra Venkatagopalan
- The Biodesign Institute, Center for Infectious Diseases and Vaccinology, Arizona State University, Tempe, AZ 85287-5401, United States; School of Life Sciences, Arizona State University, Tempe, AZ 85287-5401, United States; Microbiology Graduate Program, Arizona State University, Tempe, AZ 85287-5401, United States
| | - Sasha M Daskalova
- The Biodesign Institute, Center for Infectious Diseases and Vaccinology, Arizona State University, Tempe, AZ 85287-5401, United States; Department of Biochemistry and Chemistry, Arizona State University, Tempe, AZ 85287-5401, United States
| | - Lisa A Lopez
- The Biodesign Institute, Center for Infectious Diseases and Vaccinology, Arizona State University, Tempe, AZ 85287-5401, United States; School of Life Sciences, Arizona State University, Tempe, AZ 85287-5401, United States; Molecular and Cellular Biology Graduate Program, Arizona State University, Tempe, AZ 85287-5401, United States
| | - Kelly A Dolezal
- The Biodesign Institute, Center for Infectious Diseases and Vaccinology, Arizona State University, Tempe, AZ 85287-5401, United States; School of Life Sciences, Arizona State University, Tempe, AZ 85287-5401, United States; Microbiology Graduate Program, Arizona State University, Tempe, AZ 85287-5401, United States
| | - Brenda G Hogue
- The Biodesign Institute, Center for Infectious Diseases and Vaccinology, Arizona State University, Tempe, AZ 85287-5401, United States; School of Life Sciences, Arizona State University, Tempe, AZ 85287-5401, United States.
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185
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Katoch P, Mitra S, Ray A, Kelsey L, Roberts BJ, Wahl JK, Johnson KR, Mehta PP. The carboxyl tail of connexin32 regulates gap junction assembly in human prostate and pancreatic cancer cells. J Biol Chem 2015; 290:4647-4662. [PMID: 25548281 PMCID: PMC4335205 DOI: 10.1074/jbc.m114.586057] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2014] [Revised: 12/23/2014] [Indexed: 12/20/2022] Open
Abstract
Connexins, the constituent proteins of gap junctions, are transmembrane proteins. A connexin (Cx) traverses the membrane four times and has one intracellular and two extracellular loops with the amino and carboxyl termini facing the cytoplasm. The transmembrane and the extracellular loop domains are highly conserved among different Cxs, whereas the carboxyl termini, often called the cytoplasmic tails, are highly divergent. We have explored the role of the cytoplasmic tail of Cx32, a Cx expressed in polarized and differentiated cells, in regulating gap junction assembly. Our results demonstrate that compared with the full-length Cx32, the cytoplasmic tail-deleted Cx32 is assembled into small gap junctions in human pancreatic and prostatic cancer cells. Our results further document that the expression of the full-length Cx32 in cells, which express the tail-deleted Cx32, increases the size of gap junctions, whereas the expression of the tail-deleted Cx32 in cells, which express the full-length Cx32, has the opposite effect. Moreover, we show that the tail is required for the clustering of cell-cell channels and that in cells expressing the tail-deleted Cx32, the expression of cell surface-targeted cytoplasmic tail alone is sufficient to enhance the size of gap junctions. Our live-cell imaging data further demonstrate that gap junctions formed of the tail-deleted Cx32 are highly mobile compared with those formed of full-length Cx32. Our results suggest that the cytoplasmic tail of Cx32 is not required to initiate the assembly of gap junctions but for their subsequent growth and stability. Our findings suggest that the cytoplasmic tail of Cx32 may be involved in regulating the permeability of gap junctions by regulating their size.
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Affiliation(s)
- Parul Katoch
- From the Department of Biochemistry and Molecular Biology, Department of Oral Biology, Eppley Institute for Research in Cancer and Allied Diseases, Fred and Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, Nebraska 68198
| | - Shalini Mitra
- From the Department of Biochemistry and Molecular Biology, Department of Oral Biology, Eppley Institute for Research in Cancer and Allied Diseases, Fred and Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, Nebraska 68198
| | - Anuttoma Ray
- From the Department of Biochemistry and Molecular Biology, Department of Oral Biology, Eppley Institute for Research in Cancer and Allied Diseases, Fred and Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, Nebraska 68198
| | - Linda Kelsey
- From the Department of Biochemistry and Molecular Biology, Department of Oral Biology, Eppley Institute for Research in Cancer and Allied Diseases, Fred and Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, Nebraska 68198
| | - Brett J Roberts
- From the Department of Biochemistry and Molecular Biology, Department of Oral Biology, Eppley Institute for Research in Cancer and Allied Diseases, Fred and Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, Nebraska 68198
| | - James K Wahl
- From the Department of Biochemistry and Molecular Biology, Department of Oral Biology, Eppley Institute for Research in Cancer and Allied Diseases, Fred and Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, Nebraska 68198
| | - Keith R Johnson
- From the Department of Biochemistry and Molecular Biology, Department of Oral Biology, Eppley Institute for Research in Cancer and Allied Diseases, Fred and Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, Nebraska 68198
| | - Parmender P Mehta
- From the Department of Biochemistry and Molecular Biology, Department of Oral Biology, Eppley Institute for Research in Cancer and Allied Diseases, Fred and Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, Nebraska 68198.
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186
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Ligeon LA, Barois N, Werkmeister E, Bongiovanni A, Lafont F. Structured illumination microscopy and correlative microscopy to study autophagy. Methods 2015; 75:61-8. [PMID: 25667106 DOI: 10.1016/j.ymeth.2015.01.017] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2014] [Revised: 01/23/2015] [Accepted: 01/24/2015] [Indexed: 10/24/2022] Open
Abstract
Autophagy is a predominant eukaryotic mechanism for the engulfment of "portions" of cytoplasm allowing their degradation to recycle metabolites. The autophagy is ubiquitous among the life kingdom revealing the importance of this pathway that appears more complex than previously thought. Several reviews have already addressed how to monitor this pathway and have highlighted the existence of new routes such as the LC3-associated phagocytosis (LAP) and the non-canonical autophagy. The principal difference between autophagosomes and LAP vacuoles is that the former has two limiting membranes positives for LC3 whereas the latter has one. Herein, we propose to emphasize the use of correlative light electron microscopy (CLEM) to answer some autophagy's related questions. The structured illumination microscopy (SIM) relatively easy to implement allows to better observe the Atg proteins recruitment and localization during the autophagy process. While LC3 recruitment is performed using light microscopy the ultrastructural morphological analysis of LC3-vacuoles is ascertained by electron microscopy. Hence, these combined and correlated approaches allow to tackle the LAP vs. autophagosome issue.
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Affiliation(s)
- Laure-Anne Ligeon
- Cellular Microbiology and Physics of Infection, Center for Infection and Immunity of Lille, Institut Pasteur de Lille, F-59021 Lille, France; CNRS UMR8204, F-59021 Lille, France; University of Lille-Nord de France, F-59021 Lille, France.
| | - Nicolas Barois
- INSERM U1019, F-59021 Lille, France; BioImaging Center Lille-Nord de France, IFR142, Institut Pasteur de Lille, F-59021 Lille, France
| | | | - Antonino Bongiovanni
- Cellular Microbiology and Physics of Infection, Center for Infection and Immunity of Lille, Institut Pasteur de Lille, F-59021 Lille, France; BioImaging Center Lille-Nord de France, IFR142, Institut Pasteur de Lille, F-59021 Lille, France
| | - Frank Lafont
- Cellular Microbiology and Physics of Infection, Center for Infection and Immunity of Lille, Institut Pasteur de Lille, F-59021 Lille, France; CNRS UMR8204, F-59021 Lille, France; University of Lille-Nord de France, F-59021 Lille, France; INSERM U1019, F-59021 Lille, France; BioImaging Center Lille-Nord de France, IFR142, Institut Pasteur de Lille, F-59021 Lille, France
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187
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Boassa D, Nguyen P, Hu J, Ellisman MH, Sosinsky GE. Pannexin2 oligomers localize in the membranes of endosomal vesicles in mammalian cells while Pannexin1 channels traffic to the plasma membrane. Front Cell Neurosci 2015; 8:468. [PMID: 25698922 PMCID: PMC4313697 DOI: 10.3389/fncel.2014.00468] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2014] [Accepted: 12/27/2014] [Indexed: 12/13/2022] Open
Abstract
Pannexin2 (Panx2) is the largest of three members of the pannexin proteins. Pannexins are topologically related to connexins and innexins, but serve different functional roles than forming gap junctions. We previously showed that pannexins form oligomeric channels but unlike connexins and innexins, they form only single membrane channels. High levels of Panx2 mRNA and protein in the Central Nervous System (CNS) have been documented. Whereas Pannexin1 (Panx1) is fairly ubiquitous and Pannexin3 (Panx3) is found in skin and connective tissue, both are fully glycosylated, traffic to the plasma membrane and have functions correlated with extracellular ATP release. Here, we describe trafficking and subcellular localizations of exogenous Panx2 and Panx1 protein expression in MDCK, HeLa, and HEK 293T cells as well as endogenous Panx1 and Panx2 patterns in the CNS. Panx2 was found in intracellular localizations, was partially N-glycosylated, and localizations were non-overlapping with Panx1. Confocal images of hippocampal sections immunolabeled for the astrocytic protein GFAP, Panx1 and Panx2 demonstrated that the two isoforms, Panx1 and Panx2, localized at different subcellular compartments in both astrocytes and neurons. Using recombinant fusions of Panx2 with appended genetic tags developed for correlated light and electron microscopy and then expressed in different cell lines, we determined that Panx2 is localized in the membrane of intracellular vesicles and not in the endoplasmic reticulum as initially indicated by calnexin colocalization experiments. Dual immunofluorescence imaging with protein markers for specific vesicle compartments showed that Panx2 vesicles are early endosomal in origin. In electron tomographic volumes, cross-sections of these vesicles displayed fine structural details and close proximity to actin filaments. Thus, pannexins expressed at different subcellular compartments likely exert distinct functional roles, particularly in the nervous system.
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Affiliation(s)
- Daniela Boassa
- National Center for Microscopy and Imaging Research, Center for Research in Biological Systems, University of California San Diego, La Jolla, CA, USA
| | - Phuong Nguyen
- National Center for Microscopy and Imaging Research, Center for Research in Biological Systems, University of California San Diego, La Jolla, CA, USA
| | - Junru Hu
- National Center for Microscopy and Imaging Research, Center for Research in Biological Systems, University of California San Diego, La Jolla, CA, USA
| | - Mark H Ellisman
- National Center for Microscopy and Imaging Research, Center for Research in Biological Systems, University of California San Diego, La Jolla, CA, USA ; Department of Neurosciences, University of California San Diego, La Jolla, CA, USA
| | - Gina E Sosinsky
- National Center for Microscopy and Imaging Research, Center for Research in Biological Systems, University of California San Diego, La Jolla, CA, USA ; Department of Neurosciences, University of California San Diego, La Jolla, CA, USA
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188
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Chen B, Liu Q, Popowich A, Shen S, Yan X, Zhang Q, Li XF, Weinfeld M, Cullen WR, Le XC. Therapeutic and analytical applications of arsenic binding to proteins. Metallomics 2015; 7:39-55. [DOI: 10.1039/c4mt00222a] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Knowledge of arsenic binding to proteins advances the development of bioanalytical techniques and therapeutic drugs.
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Affiliation(s)
- Beibei Chen
- Division of Analytical and Environmental Toxicology
- Department of Laboratory Medicine and Pathology
- University of Alberta
- Edmonton, Canada
| | - Qingqing Liu
- Division of Analytical and Environmental Toxicology
- Department of Laboratory Medicine and Pathology
- University of Alberta
- Edmonton, Canada
| | | | - Shengwen Shen
- Division of Analytical and Environmental Toxicology
- Department of Laboratory Medicine and Pathology
- University of Alberta
- Edmonton, Canada
| | - Xiaowen Yan
- Division of Analytical and Environmental Toxicology
- Department of Laboratory Medicine and Pathology
- University of Alberta
- Edmonton, Canada
| | - Qi Zhang
- Division of Analytical and Environmental Toxicology
- Department of Laboratory Medicine and Pathology
- University of Alberta
- Edmonton, Canada
| | - Xing-Fang Li
- Division of Analytical and Environmental Toxicology
- Department of Laboratory Medicine and Pathology
- University of Alberta
- Edmonton, Canada
| | | | - William R. Cullen
- Department of Chemistry
- University of British Columbia
- Vancouver, Canada
| | - X. Chris Le
- Division of Analytical and Environmental Toxicology
- Department of Laboratory Medicine and Pathology
- University of Alberta
- Edmonton, Canada
- Department of Chemistry
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189
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Kelly JJ, Shao Q, Jagger DJ, Laird DW. Cx30 exhibits unique characteristics including a long half-life when assembled into gap junctions. J Cell Sci 2015; 128:3947-60. [DOI: 10.1242/jcs.174698] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2015] [Accepted: 09/08/2015] [Indexed: 01/04/2023] Open
Abstract
In the present study we investigated the life-cycle, trafficking, assembly and cell surface dynamics of a poorly characterized connexin family member, connexin 30 (Cx30), which plays a critical role in skin health and hearing. Unexpectedly, Cx30 localization at the cell surface and gap junctional intercellular communication was not affected by prolonged treatments with the ER-Golgi transport inhibitor brefeldin-A or the protein synthesis inhibitor cycloheximide, whereas Cx43 was rapidly cleared. Fluorescent recovery after photobleaching revealed that Cx30 plaques were rebuilt from the outer edges in keeping with older channels residing in the inner core of the plaque. Expression of a dominant-negative form of Sar1 GTPase led to the accumulation of Cx30 within the ER in contrast to a report that Cx30 traffics via a Golgi-independent pathway. Co-expression of Cx30 with Cx43 revealed that these connexins segregate into distinct domains within common gap junction plaques suggesting their assembly is governed by different mechanisms. In summary, Cx30 was found to be an unusually stable, long-lived connexin (half-life >12 hrs), which may underlie its specific role in the epidermis and cochlea.
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Affiliation(s)
- John J. Kelly
- Department of Anatomy and Cell Biology, University of Western Ontario, London, Ontario, Canada
| | - Qing Shao
- Department of Anatomy and Cell Biology, University of Western Ontario, London, Ontario, Canada
| | | | - Dale W. Laird
- Department of Anatomy and Cell Biology, University of Western Ontario, London, Ontario, Canada
- Department of Physiology and Pharmacology, University of Western Ontario, London, Ontario, Canada
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190
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Griffin BA, Adams SR, Tsien RY. How FlAsH got its sparkle: historical recollections of the biarsenical-tetracysteine tag. Methods Mol Biol 2015; 1266:1-6. [PMID: 25560064 DOI: 10.1007/978-1-4939-2272-7_1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
The biarsenical-tetracysteine tagging system was the first of (and inspiration for) the now numerous methods for site-specifically labeling proteins in living cells with small molecules such as fluorophores. This historical recollection describes its conception and the trial-and-error chemical development required to become a versatile technique.
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191
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Kubota R, Hamachi I. Protein recognition using synthetic small-molecular binders toward optical protein sensing in vitro and in live cells. Chem Soc Rev 2015; 44:4454-71. [DOI: 10.1039/c4cs00381k] [Citation(s) in RCA: 96] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
This review describes the recognition and sensing techniques of proteins and their building blocks by use of small synthetic binders.
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Affiliation(s)
- Ryou Kubota
- Department of Synthetic Chemistry and Biological Chemistry
- Graduate School of Engineering
- Kyoto University
- Katsura
- Japan
| | - Itaru Hamachi
- Department of Synthetic Chemistry and Biological Chemistry
- Graduate School of Engineering
- Kyoto University
- Katsura
- Japan
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192
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Lam SS, Martell JD, Kamer KJ, Deerinck TJ, Ellisman MH, Mootha VK, Ting AY. Directed evolution of APEX2 for electron microscopy and proximity labeling. Nat Methods 2015; 12:51-4. [PMID: 25419960 PMCID: PMC4296904 DOI: 10.1038/nmeth.3179] [Citation(s) in RCA: 888] [Impact Index Per Article: 98.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Accepted: 10/15/2014] [Indexed: 12/12/2022]
Abstract
APEX is an engineered peroxidase that functions as an electron microscopy tag and a promiscuous labeling enzyme for live-cell proteomics. Because limited sensitivity precludes applications requiring low APEX expression, we used yeast-display evolution to improve its catalytic efficiency. APEX2 is far more active in cells, enabling the use of electron microscopy to resolve the submitochondrial localization of calcium uptake regulatory protein MICU1. APEX2 also permits superior enrichment of endogenous mitochondrial and endoplasmic reticulum membrane proteins.
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Affiliation(s)
- Stephanie S Lam
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Jeffrey D Martell
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Kimberli J Kamer
- Department of Molecular Biology, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Thomas J Deerinck
- National Center for Microscopy and Imaging Research, University of California at San Diego, La Jolla, California, USA
| | - Mark H Ellisman
- 1] National Center for Microscopy and Imaging Research, University of California at San Diego, La Jolla, California, USA. [2] Department of Neurosciences, University of California at San Diego, La Jolla, California, USA
| | - Vamsi K Mootha
- Department of Molecular Biology, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Alice Y Ting
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
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193
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Xiao S, Shaw RM. Cardiomyocyte protein trafficking: Relevance to heart disease and opportunities for therapeutic intervention. Trends Cardiovasc Med 2014; 25:379-89. [PMID: 25649302 DOI: 10.1016/j.tcm.2014.12.012] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Revised: 12/18/2014] [Accepted: 12/20/2014] [Indexed: 11/30/2022]
Abstract
Cardiomyocytes, the individual contractile units of heart muscle, are long-lived and robust. Given the longevity of these cells, it can be easy to overlook their dynamic intracellular environment that contain rapid protein movements and frequent protein turnover. Critical gene transcription and protein translation occur continuously, as well as trafficking and localization of proteins to specific functional zones of cell membrane. As heart failure becomes an increasingly important clinical entity, growing numbers of investigative teams are examining the cell biology of healthy and diseased cardiomyocytes. In this review, we introduce the major architectural structures and types of protein movements within cardiac cells, and then review recent studies that explore the regulation of such movements. We conclude by introducing current translational directions of the basic studies with a focus on novel areas of therapeutic development.
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Affiliation(s)
- Shaohua Xiao
- Heart Institute and Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, CA
| | - Robin M Shaw
- Heart Institute and Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, CA; Department of Medicine, University of California Los Angeles, Los Angeles, CA.
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194
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Karreman MA, Mercier L, Schieber NL, Shibue T, Schwab Y, Goetz JG. Correlating intravital multi-photon microscopy to 3D electron microscopy of invading tumor cells using anatomical reference points. PLoS One 2014; 9:e114448. [PMID: 25479106 PMCID: PMC4257674 DOI: 10.1371/journal.pone.0114448] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2014] [Accepted: 11/06/2014] [Indexed: 01/24/2023] Open
Abstract
Correlative microscopy combines the advantages of both light and electron microscopy to enable imaging of rare and transient events at high resolution. Performing correlative microscopy in complex and bulky samples such as an entire living organism is a time-consuming and error-prone task. Here, we investigate correlative methods that rely on the use of artificial and endogenous structural features of the sample as reference points for correlating intravital fluorescence microscopy and electron microscopy. To investigate tumor cell behavior in vivo with ultrastructural accuracy, a reliable approach is needed to retrieve single tumor cells imaged deep within the tissue. For this purpose, fluorescently labeled tumor cells were subcutaneously injected into a mouse ear and imaged using two-photon-excitation microscopy. Using near-infrared branding, the position of the imaged area within the sample was labeled at the skin level, allowing for its precise recollection. Following sample preparation for electron microscopy, concerted usage of the artificial branding and anatomical landmarks enables targeting and approaching the cells of interest while serial sectioning through the specimen. We describe here three procedures showing how three-dimensional (3D) mapping of structural features in the tissue can be exploited to accurately correlate between the two imaging modalities, without having to rely on the use of artificially introduced markers of the region of interest. The methods employed here facilitate the link between intravital and nanoscale imaging of invasive tumor cells, enabling correlating function to structure in the study of tumor invasion and metastasis.
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Affiliation(s)
- Matthia A. Karreman
- European Molecular Biology Laboratory Heidelberg, Heidelberg, 69117, Germany
| | - Luc Mercier
- Inserm U1109, MN3T, Strasbourg, F-67200, France
- Université de Strasbourg, Strasbourg, F-67000, France
- LabEx Medalis, Université de Strasbourg, Strasbourg, F-67000, France
- Fédération de Médecine Translationnelle de Strasbourg (FMTS), Strasbourg, F-67000, France
| | - Nicole L. Schieber
- European Molecular Biology Laboratory Heidelberg, Heidelberg, 69117, Germany
| | - Tsukasa Shibue
- Whitehead Institute for Biomedical Research, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Yannick Schwab
- European Molecular Biology Laboratory Heidelberg, Heidelberg, 69117, Germany
- * E-mail: (YS); (JGG)
| | - Jacky G. Goetz
- Inserm U1109, MN3T, Strasbourg, F-67200, France
- Université de Strasbourg, Strasbourg, F-67000, France
- LabEx Medalis, Université de Strasbourg, Strasbourg, F-67000, France
- Fédération de Médecine Translationnelle de Strasbourg (FMTS), Strasbourg, F-67000, France
- * E-mail: (YS); (JGG)
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195
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Fukushima S, Furukawa T, Niioka H, Ichimiya M, Miyake J, Ashida M, Araki T, Hashimoto M. Y 2 O 3 :Tm,Yb nanophosphors for correlative upconversion luminescence and cathodoluminescence imaging. Micron 2014; 67:90-95. [DOI: 10.1016/j.micron.2014.07.002] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2014] [Revised: 06/06/2014] [Accepted: 07/09/2014] [Indexed: 11/16/2022]
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196
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Kelly JJ, Simek J, Laird DW. Mechanisms linking connexin mutations to human diseases. Cell Tissue Res 2014; 360:701-21. [DOI: 10.1007/s00441-014-2024-4] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2014] [Accepted: 09/26/2014] [Indexed: 11/30/2022]
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197
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Liu DS, Nivón LG, Richter F, Goldman PJ, Deerinck TJ, Yao JZ, Richardson D, Phipps WS, Ye AZ, Ellisman MH, Drennan CL, Baker D, Ting AY. Computational design of a red fluorophore ligase for site-specific protein labeling in living cells. Proc Natl Acad Sci U S A 2014; 111:E4551-9. [PMID: 25313043 PMCID: PMC4217414 DOI: 10.1073/pnas.1404736111] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Chemical fluorophores offer tremendous size and photophysical advantages over fluorescent proteins but are much more challenging to target to specific cellular proteins. Here, we used Rosetta-based computation to design a fluorophore ligase that accepts the red dye resorufin, starting from Escherichia coli lipoic acid ligase. X-ray crystallography showed that the design closely matched the experimental structure. Resorufin ligase catalyzed the site-specific and covalent attachment of resorufin to various cellular proteins genetically fused to a 13-aa recognition peptide in multiple mammalian cell lines and in primary cultured neurons. We used resorufin ligase to perform superresolution imaging of the intermediate filament protein vimentin by stimulated emission depletion and electron microscopies. This work illustrates the power of Rosetta for major redesign of enzyme specificity and introduces a tool for minimally invasive, highly specific imaging of cellular proteins by both conventional and superresolution microscopies.
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Affiliation(s)
| | | | - Florian Richter
- Department of Biochemistry, Graduate Program in Biological Physics, Structure and Design, University of Washington, Seattle, WA 98195
| | | | - Thomas J Deerinck
- National Center for Microscopy and Imaging Research, Center for Research on Biological Systems and
| | | | - Douglas Richardson
- Department of NanoBiophotonics, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany
| | | | | | - Mark H Ellisman
- National Center for Microscopy and Imaging Research, Center for Research on Biological Systems and Department of Neurosciences, University of California, San Diego, La Jolla, CA 92093; and
| | - Catherine L Drennan
- Departments of Chemistry and Biology and Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, MA 02139
| | - David Baker
- Department of Biochemistry, Howard Hughes Medical Institute, and
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198
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Abstract
Correlative fluorescence and electron microscopy (CFEM) is a multimodal technique that combines dynamic and localization information from fluorescence methods with ultrastructural data from electron microscopy, to give new information about how cellular components change relative to the spatiotemporal dynamics within their environment. In this review, we will discuss some of the basic techniques and tools of the trade for utilizing this attractive research method, which is becoming a very powerful tool for biology labs. The information obtained from correlative methods has proven to be invaluable in creating consensus between the two types of microscopy, extending the capability of each, and cutting the time and expense associated with using each method separately for comparative analysis. The realization of the advantages of these methods in cell biology has led to rapid improvement in the protocols and has ushered in a new generation of instruments to reach the next level of correlation--integration.
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Affiliation(s)
- Randall T Schirra
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
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199
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Umebayashi D, Natsume A, Takeuchi H, Hara M, Nishimura Y, Fukuyama R, Sumiyoshi N, Wakabayashi T. Blockade of gap junction hemichannel protects secondary spinal cord injury from activated microglia-mediated glutamate exitoneurotoxicity. J Neurotrauma 2014; 31:1967-74. [PMID: 24588281 DOI: 10.1089/neu.2013.3223] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
We previously demonstrated that activated microglia release excessive glutamate through gap junction hemichannels and identified a novel gap junction hemichannel blocker, INI-0602, that was proven to penetrate the blood-brain barrier and be an effective treatment in mouse models of amyotrophic lateral sclerosis and Alzheimer disease. Spinal cord injury causes tissue damage in two successive waves. The initial injury is mechanical and directly causes primary tissue damage, which induces subsequent ischemia, inflammation, and neurotoxic factor release resulting in the secondary tissue damage. These lead to activation of glial cells. Activated glial cells such as microglia and astrocytes are common pathological observations in the damaged lesion. Activated microglia release glutamate, the major neurotoxic factor released into the extracellular space after neural injury, which causes neuronal death at high concentration. In the present study, we demonstrate that reduction of glutamate-mediated exitotoxicity via intraperitoneal administration of INI-0602 in the microenvironment of the injured spinal cord elicited neurobehavioral recovery and extensive suppression of glial scar formation by reducing secondary tissue damage. Further, this intervention stimulated anti-inflammatory cytokines, and subsequently elevated brain-derived neurotrophic factor. Thus, preventing microglial activation by a gap junction hemichannel blocker, INI-0602, may be a promising therapeutic strategy in spinal cord injury.
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Affiliation(s)
- Daisuke Umebayashi
- 1 Department of Neurosurgery, Nagoya University School of Medicine , Nagoya, Japan
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200
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Zhang SS, Shaw RM. Trafficking highways to the intercalated disc: new insights unlocking the specificity of connexin 43 localization. ACTA ACUST UNITED AC 2014; 21:43-54. [PMID: 24460200 DOI: 10.3109/15419061.2013.876014] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
With each heartbeat, billions of cardiomyocytes work in concert to propagate the electrical excitation needed to effectively circulate blood. Regulated expression and timely delivery of connexin proteins to form gap junctions at the specialized cell-cell contact region, known as the intercalated disc, is essential to ventricular cardiomyocyte coupling. We focus this review on several regulatory mechanisms that have been recently found to govern the lifecycle of connexin 43 (Cx43), the short-lived and most abundantly expressed connexin in cardiac ventricular muscle. The Cx43 lifecycle begins with gene expression, followed by oligomerization into hexameric channels, and then cytoskeletal-based transport toward the disc region. Once delivered, hemichannels interact with resident disc proteins and are organized to effect intercellular coupling. We highlight recent studies exploring regulation of Cx43 localization to the intercalated disc, with emphasis on alternatively translated Cx43 isoforms and cytoskeletal transport machinery that together regulate Cx43 gap junction coupling between cardiomyocytes.
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