1
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Eliad B, Schneider N, Ben-Naim Zgayer O, Amichan Y, Glaser F, Erdmann EA, Rajendren S, Hundley HA, Lamm AT. ADBP-1 regulates ADR-2 nuclear localization to control editing substrate selection. Nucleic Acids Res 2024:gkae641. [PMID: 39036970 DOI: 10.1093/nar/gkae641] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Revised: 06/05/2024] [Accepted: 07/09/2024] [Indexed: 07/23/2024] Open
Abstract
Adenosine-to-inosine (A-to-I) RNA editing, catalyzed by ADAR enzymes, is a prevalent and conserved RNA modification. While A-to-I RNA editing is essential in mammals, in Caenorhabditis elegans, it is not, making them invaluable for RNA editing research. In C. elegans, ADR-2 is the sole catalytic A-to-I editing enzyme, and ADR-1 is an RNA editing regulator. ADAR localization is well-studied in humans but not well-established in C. elegans. In this study, we examine the cellular and tissue-specific localization of ADR-2. We show that while ADR-2 is present in most cells in the embryo, at later developmental stages, its expression is both tissue- and cell-type-specific. Additionally, both ADARs are mainly in the nucleus. ADR-2 is adjacent to the chromosomes during the cell cycle. We show that the nuclear localization of endogenous ADR-2 depends on ADBP-1, not ADR-1. In adbp-1 mutant worms, ADR-2 is mislocalized, while ADR-1 is not, leading to decreased editing levels and de-novo editing, mostly in exons, suggesting that ADR-2 is also functional in the cytoplasm. Besides, mutated ADBP-1 affects gene expression. Furthermore, we show that ADR-2 targets adenosines with different surrounding nucleotides in exons and introns. Our findings indicate that ADR-2 cellular localization is highly regulated and affects its function.
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Affiliation(s)
- Berta Eliad
- Faculty of Biology, Technion- Israel Institute of Technology, Technion City, Haifa 3200003, Israel
| | - Noa Schneider
- Faculty of Biology, Technion- Israel Institute of Technology, Technion City, Haifa 3200003, Israel
| | - Orna Ben-Naim Zgayer
- Faculty of Biology, Technion- Israel Institute of Technology, Technion City, Haifa 3200003, Israel
| | - Yarden Amichan
- Faculty of Biology, Technion- Israel Institute of Technology, Technion City, Haifa 3200003, Israel
| | - Fabian Glaser
- Technion Center for Structural Biology, Technion Human Health Initiative, Technion, Haifa 32000, Israel
| | - Emily A Erdmann
- Department of Biology, Indiana University, Bloomington, IN 47405, USA
| | - Suba Rajendren
- Department of Biology, Indiana University, Bloomington, IN 47405, USA
| | - Heather A Hundley
- Department of Biology, Indiana University, Bloomington, IN 47405, USA
| | - Ayelet T Lamm
- Faculty of Biology, Technion- Israel Institute of Technology, Technion City, Haifa 3200003, Israel
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2
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Eliad B, Schneider N, Zgayer OBN, Amichan Y, Glaser F, Erdmann EA, Rajendren S, Hundley HA, Lamm AT. ADBP-1 regulates ADR-2 nuclear localization to control editing substrate selection. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.05.14.540679. [PMID: 38895382 PMCID: PMC11185548 DOI: 10.1101/2023.05.14.540679] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/21/2024]
Abstract
Adenosine-to-inosine (A-to-I) RNA editing, catalyzed by ADAR enzymes, is a prevalent and conserved RNA modification. While A-to-I RNA editing is essential in mammals, in Caenorhabditis elegans , it is not, making them invaluable for RNA editing research. In C. elegans , ADR-2 is the sole catalytic A-to-I editing enzyme, and ADR-1 is an RNA editing regulator. ADAR localization is well-studied in humans but not well-established in C. elegans . In this study, we examine the cellular and tissue-specific localization of ADR-2. We show that while ADR-2 is present in most cells in the embryo, at later developmental stages, its expression is both tissue- and cell-type-specific. Additionally, both ADARs are mainly in the nucleus. ADR-2 is adjacent to the chromosomes during the cell cycle. We show that the nuclear localization of endogenous ADR-2 depends on ADBP-1, not ADR-1. In adbp-1 mutant worms, ADR-2 is mislocalized, while ADR-1 is not, leading to decreased editing levels and de-novo editing, mostly in exons, suggesting that ADR-2 is also functional in the cytoplasm. Besides, mutated ADBP-1 affects gene expression. Furthermore, we show that ADR-2 targets adenosines with different surrounding nucleotides in exons and introns. Our findings indicate that ADR-2 cellular localization is highly regulated and affects its function.
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3
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Jelinska C, Kannan S, Frosi Y, Ramlan SR, Winnerdy F, Lakshminarayanan R, Johannes CW, Brown CJ, Phan AT, Rhodes D, Verma CS. Stitched peptides as potential cell permeable inhibitors of oncogenic DAXX protein. RSC Chem Biol 2023; 4:1096-1110. [PMID: 38033728 PMCID: PMC10685803 DOI: 10.1039/d3cb00149k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2023] [Accepted: 09/25/2023] [Indexed: 12/02/2023] Open
Abstract
DAXX (Death Domain Associated Protein 6) is frequently upregulated in various common cancers, and its suppression has been linked to reduced tumor progression. Consequently, DAXX has gained significant interest as a therapeutic target in such cancers. DAXX is known to function in several critical biological pathways including chromatin remodelling, transcription regulation, and DNA repair. Leveraging structural information, we have designed and developed a novel set of stapled/stitched peptides that specifically target a surface on the N-terminal helical bundle domain of DAXX. This surface serves as the anchor point for binding to multiple interaction partners, such as Rassf1C, p53, Mdm2, and ATRX, as well as for the auto-regulation of the DAXX N-terminal SUMO interaction motif (SIM). Our experiments demonstrate that these peptides effectively bind to and inhibit DAXX with a higher affinity than the known interaction partners. Furthermore, these peptides release the auto-inhibited SIM, enabling it to interact with SUMO-1. Importantly, we have developed stitched peptides that can enter cells, maintaining their intracellular concentrations at nanomolar levels even after 24 hours, without causing any membrane perturbation. Collectively, our findings suggest that these stitched peptides not only serve as valuable tools for probing the molecular interactions of DAXX but also hold potential as precursors to the development of therapeutic interventions.
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Affiliation(s)
- Clare Jelinska
- NTU Institute of Structural Biology, Experimental Medicine Building Level 06-01, 59 Nanyang Drive 636921 Singapore
- NTU School of Biological Sciences, 60 Nanyang Drive 637551 Singapore
- NTU Lee Kong Chian School of Medicine, Experimental Medicine Building, 59 Nanyang Drive 636921 Singapore
| | | | - Yuri Frosi
- DITL, Institute of Cellular and Molecular Biology (A*STAR), 8a Biomedical Grove 138648 Singapore
| | - Siti Radhiah Ramlan
- DITL, Institute of Cellular and Molecular Biology (A*STAR), 8a Biomedical Grove 138648 Singapore
| | - Fernaldo Winnerdy
- NTU Institute of Structural Biology, Experimental Medicine Building Level 06-01, 59 Nanyang Drive 636921 Singapore
| | - Rajamani Lakshminarayanan
- Ocular Infections and Anti-Microbials Research Group, Singapore Eye Research Institute, The Academia, 20 College Road Singapore 169856 Singapore
- Department of Pharmacy, National University of Singapore Singapore 117543 Singapore
- Academic Clinical Program in Ophthalmology and Visual Sciences Academic Clinical Program, Duke-NUS Medical School 169857 Singapore
| | - Charles W Johannes
- DITL, Institute of Cellular and Molecular Biology (A*STAR), 8a Biomedical Grove 138648 Singapore
| | - Christopher J Brown
- DITL, Institute of Cellular and Molecular Biology (A*STAR), 8a Biomedical Grove 138648 Singapore
| | - Anh-Tuan Phan
- NTU Institute of Structural Biology, Experimental Medicine Building Level 06-01, 59 Nanyang Drive 636921 Singapore
- NTU School of Physical and Mathematical Sciences. 21 Nanyang link 637371 Singapore
| | - Daniela Rhodes
- NTU Institute of Structural Biology, Experimental Medicine Building Level 06-01, 59 Nanyang Drive 636921 Singapore
- NTU School of Biological Sciences, 60 Nanyang Drive 637551 Singapore
- NTU Lee Kong Chian School of Medicine, Experimental Medicine Building, 59 Nanyang Drive 636921 Singapore
| | - Chandra S Verma
- NTU School of Biological Sciences, 60 Nanyang Drive 637551 Singapore
- Bioinformatics institute (A*STAR), 30 Biopolis Street, Matrix Level 07-01 138671 Singapore
- Department of Biological Sciences, National University of Singapore Block S3 #05-01 16 Science Drive 4 117558 Singapore
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4
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van der Zanden SY, Jongsma MLM, Neefjes ACM, Berlin I, Neefjes J. Maintaining soluble protein homeostasis between nuclear and cytoplasmic compartments across mitosis. Trends Cell Biol 2023; 33:18-29. [PMID: 35778326 DOI: 10.1016/j.tcb.2022.06.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 05/23/2022] [Accepted: 06/06/2022] [Indexed: 12/27/2022]
Abstract
The nuclear envelope (NE) is central to the architecture of eukaryotic cells, both as a physical barrier separating the nucleus from the cytoplasm and as gatekeeper of selective transport between them. However, in open mitosis, the NE fragments to allow for spindle formation and segregation of chromosomes, resulting in intermixing of nuclear and cytoplasmic soluble fractions. Recent studies have shed new light on the mechanisms driving reinstatement of soluble proteome homeostasis following NE reformation in daughter cells. Here, we provide an overview of how mitotic cells confront this challenge to ensure continuity of basic cellular functions across generations and elaborate on the implications for the proteasome - a macromolecular machine that functions in both cytoplasmic and nuclear compartments.
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Affiliation(s)
- Sabina Y van der Zanden
- Department of Cell and Chemical Biology, ONCODE Institute, Leiden University Medical Center LUMC, 2333, ZC, Leiden, The Netherlands
| | - Marlieke L M Jongsma
- Department of Cell and Chemical Biology, ONCODE Institute, Leiden University Medical Center LUMC, 2333, ZC, Leiden, The Netherlands
| | - Anna C M Neefjes
- Department of Cell and Chemical Biology, ONCODE Institute, Leiden University Medical Center LUMC, 2333, ZC, Leiden, The Netherlands
| | - Ilana Berlin
- Department of Cell and Chemical Biology, ONCODE Institute, Leiden University Medical Center LUMC, 2333, ZC, Leiden, The Netherlands.
| | - Jacques Neefjes
- Department of Cell and Chemical Biology, ONCODE Institute, Leiden University Medical Center LUMC, 2333, ZC, Leiden, The Netherlands.
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5
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Walker E, Jensen L, Croft S, Wei K, Fulcher AJ, Jans DA, Ghildyal R. Rhinovirus 16 2A Protease Affects Nuclear Localization of 3CD during Infection. J Virol 2016; 90:11032-11042. [PMID: 27681132 PMCID: PMC5126362 DOI: 10.1128/jvi.00974-16] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Accepted: 09/11/2016] [Indexed: 01/08/2023] Open
Abstract
The human rhinovirus (HRV) 3C and 2A proteases (3Cpro and 2Apro, respectively) are critical in HRV infection, as they are required for viral polyprotein processing as well as proteolysing key host factors to facilitate virus replication. Early in infection, 3Cpro is present as its precursor 3CD, which, although the mechanism of subcellular targeting is unknown, is found in the nucleus as well as the cytoplasm. In this study, we use transfected and infected cell systems to show that 2Apro activity is required for 3CD nuclear localization. Using green fluorescent protein (GFP)-tagged forms of 3Cpro, 3D, and mutant derivatives thereof, we show that 3Cpro is located in the cytoplasm and the nucleus, whereas 3CD and 3D are localized predominantly in the cytoplasm, implying that 3D lacks nuclear targeting ability and that 3Cpro activity within 3CD is not sufficient to allow the larger protein into the nucleus. Importantly, by coexpressing mCherry-2Apro fusion proteins, we demonstrate formally that 2Apro activity is required to allow HRV 3CD access to the nucleus. In contrast, mCherry-3Cpro is insufficient to allow 3CD access to the nucleus. Finally, we confirm the relevance of these results to HRV infection by demonstrating that nuclear localization of 3CD correlates with 2Apro activity and not 3Cpro activity, which is observed only later in infection. The results thus define the temporal activities of 2Apro and 3CD/3Cpro activities in HRV serotype16 infection. IMPORTANCE The human rhinovirus genome encodes two proteases, 2A and 3C, as well as a precursor protease, 3CD. These proteases are essential for efficient virus replication. The 3CD protein is found in the nucleus early during infection, though the mechanism of subcellular localization is unknown. Here we show that 2A protease is required for this localization, the 3C protease activity of 3CD is not sufficient to allow 3CD entry into the nucleus, and 3D lacks nuclear targeting ability. This study demonstrates that both 2A and 3C proteases are required for the correct localization of proteins during infection and defines the temporal regulation of 2A and 3CD/3C protease activities during HRV16 infection.
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Affiliation(s)
- Erin Walker
- Centre for Research in Therapeutic Solutions, University of Canberra, Canberra, Australian Capital Territory, Australia
| | - Lora Jensen
- Centre for Research in Therapeutic Solutions, University of Canberra, Canberra, Australian Capital Territory, Australia
| | - Sarah Croft
- Centre for Research in Therapeutic Solutions, University of Canberra, Canberra, Australian Capital Territory, Australia
| | - Kejun Wei
- Centre for Research in Therapeutic Solutions, University of Canberra, Canberra, Australian Capital Territory, Australia
| | - Alex J Fulcher
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia
- Monash Micro Imaging, Monash University, Clayton, Victoria, Australia
| | - David A Jans
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia
| | - Reena Ghildyal
- Centre for Research in Therapeutic Solutions, University of Canberra, Canberra, Australian Capital Territory, Australia
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6
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Courtney J, Woods E, Scholz D, Hall WW, Gautier VW. MATtrack: A MATLAB-Based Quantitative Image Analysis Platform for Investigating Real-Time Photo-Converted Fluorescent Signals in Live Cells. PLoS One 2015; 10:e0140209. [PMID: 26485569 PMCID: PMC4616565 DOI: 10.1371/journal.pone.0140209] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2015] [Accepted: 09/23/2015] [Indexed: 11/18/2022] Open
Abstract
We introduce here MATtrack, an open source MATLAB-based computational platform developed to process multi-Tiff files produced by a photo-conversion time lapse protocol for live cell fluorescent microscopy. MATtrack automatically performs a series of steps required for image processing, including extraction and import of numerical values from Multi-Tiff files, red/green image classification using gating parameters, noise filtering, background extraction, contrast stretching and temporal smoothing. MATtrack also integrates a series of algorithms for quantitative image analysis enabling the construction of mean and standard deviation images, clustering and classification of subcellular regions and injection point approximation. In addition, MATtrack features a simple user interface, which enables monitoring of Fluorescent Signal Intensity in multiple Regions of Interest, over time. The latter encapsulates a region growing method to automatically delineate the contours of Regions of Interest selected by the user, and performs background and regional Average Fluorescence Tracking, and automatic plotting. Finally, MATtrack computes convenient visualization and exploration tools including a migration map, which provides an overview of the protein intracellular trajectories and accumulation areas. In conclusion, MATtrack is an open source MATLAB-based software package tailored to facilitate the analysis and visualization of large data files derived from real-time live cell fluorescent microscopy using photoconvertible proteins. It is flexible, user friendly, compatible with Windows, Mac, and Linux, and a wide range of data acquisition software. MATtrack is freely available for download at eleceng.dit.ie/courtney/MATtrack.zip.
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Affiliation(s)
- Jane Courtney
- Dublin Institute of Technology, Kevin St, Dublin, Ireland
- * E-mail:
| | - Elena Woods
- UCD Centre for Research in Infectious Diseases, School of Medicine and Medical Science, University College Dublin (UCD), Dublin, Ireland
| | - Dimitri Scholz
- UCD Conway Institute of Biomolecular & Biomedical Research, School of Medicine and Biomedical Science University College Dublin (UCD), Dublin, Ireland
| | - William W. Hall
- UCD Centre for Research in Infectious Diseases, School of Medicine and Medical Science, University College Dublin (UCD), Dublin, Ireland
| | - Virginie W. Gautier
- UCD Centre for Research in Infectious Diseases, School of Medicine and Medical Science, University College Dublin (UCD), Dublin, Ireland
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7
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Solovyev AG, Minina EA, Makarova SS, Erokhina TN, Makarov VV, Kaplan IB, Kopertekh L, Schiemann J, Richert-Pöggeler KR, Morozov SY. Subcellular localization and self-interaction of plant-specific Nt-4/1 protein. Biochimie 2013; 95:1360-70. [PMID: 23499290 DOI: 10.1016/j.biochi.2013.02.015] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2013] [Accepted: 02/26/2013] [Indexed: 11/26/2022]
Abstract
The Nicotiana tabacum Nt-4/1 protein is a plant-specific protein of unknown function. Analysis of bacterially expressed Nt-4/1 protein in vitro revealed that the protein secondary structure is mostly alpha-helical and suggested that it could consist of three structural domains. Earlier studies of At-4/1, the Arabidopsis thaliana-encoded ortholog of Nt-4/1, demonstrated that GFP-fused At-4/1 was capable of polar localization in plant cells, association with plasmodesmata, and cell-to-cell transport. Together with the At-4/1 ability to interact with a plant virus movement protein, these data supported the hypothesis of the At-4/1 protein involvement in viral transport through plasmodesmata. Studies of the Nt-4/1-GFP fusion protein reported in this paper revealed that the protein was localized to cytoplasmic bodies, which were co-aligned with actin filaments and capable of actin-dependent intracellular movement. The Nt-4/1-GFP bodies, being non-membrane structures, were found in association with the plasma membrane, the tubular endoplasmic reticulum and endosome-like structures. Bimolecular fluorescence complementation experiments and inhibition of nuclear export showed that the Nt-4/1 protein was capable of nuclear-cytoplasmic transport. The nuclear export signal (NES) was identified in the Nt-4/1 protein by site-directed mutagenesis. The Nt-4/1 NES mutant was localized to the nucleoplasm forming spherical bodies. Immunogold labeling and electron microscopy of cytoplasmic Nt-4/1-containing bodies and nuclear structures containing the Nt-4/1 NES mutant revealed differences in their fine structure. In mammalian cells, Nt-4/1-GFP formed cytoplasmic spherical bodies similar to those found for the Nt-4/1 NES mutant in plant cell nuclei. Using dynamic laser light scattering and electron microscopy, the Nt-4/1 protein was found to form multimeric complexes in vitro.
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Affiliation(s)
- A G Solovyev
- A.N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Chochlova Str. 1, 119992 Moscow, Russia
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8
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Abstract
In commemoration of the 20th anniversary of the molecular cloning of the gene for the green fluorescent protein from the jellyfish Aequorea victoria, I would like to reflect on the development of new fluorescence imaging technology in the last two decades. As this technology has become increasingly diversified, it has become more and more of a challenge to come up with a comprehensive and exhaustive review of it. Here I will focus on optogenetics and large-scale, three-dimensional reconstruction. Those two technological innovations have been achieved in the neuroscience community owing to the combined efforts of molecular biologists and light microscopists. In addition, modern fluorescence imaging has indeed improved our understanding of the spatiotemporal regulation of fundamental biological functions at cellular level. As an example, I will introduce some findings we made regarding the movement of biomolecules across the nuclear membrane. The above-mentioned imaging approaches are possible today but were impossible two decades ago.
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Affiliation(s)
- Atsushi Miyawaki
- Brain Science Institute, RIKEN and Life Function and Dynamics, ERATO, JST, 2-1 Hirosawa, Wako-city, Saitama, Japan.
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9
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Use of Kikume green-red fusions to study the influence of pharmacological chaperones on trafficking of G protein-coupled receptors. FEBS Lett 2012; 586:784-91. [DOI: 10.1016/j.febslet.2012.01.043] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2011] [Revised: 01/17/2012] [Accepted: 01/22/2012] [Indexed: 11/22/2022]
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10
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Symens N, Soenen SJ, Rejman J, Braeckmans K, De Smedt SC, Remaut K. Intracellular partitioning of cell organelles and extraneous nanoparticles during mitosis. Adv Drug Deliv Rev 2012; 64:78-94. [PMID: 22210278 DOI: 10.1016/j.addr.2011.11.012] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2011] [Revised: 11/21/2011] [Accepted: 11/23/2011] [Indexed: 02/06/2023]
Abstract
The nucleocytoplasmic partitioning of nanoparticles as a result of cell division is highly relevant to the field of nonviral gene delivery. We reviewed the literature on the intracellular distribution of cell organelles (the endosomal vesicles, Golgi apparatus, endoplasmic reticulum and nucleus), foreign macromolecules (dextrans and plasmid DNA) and inorganic nanoparticles (gold, quantum dot and iron oxide) during mitosis. For nonviral gene delivery particles (lipid- or polymer-based), indirect proof of nuclear entry during mitosis is provided. We also describe how retroviruses and latent DNA viruses take advantage of mitosis to transfer their viral genome and segregate their episomes into the host daughter nuclei. Based on this knowledge, we propose strategies to improve nonviral gene delivery in dividing cells with the ultimate goal of designing nonviral gene delivery systems that are as efficient as their viral counterparts but non-immunogenic, non-oncogenic and easy and inexpensive to prepare.
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Affiliation(s)
- Nathalie Symens
- Laboratory of General Biochemistry and Physical Pharmacy, Ghent Research Group on Nanomedicines, Ghent University, Ghent, Belgium.
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11
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Proteins on the move: insights gained from fluorescent protein technologies. Nat Rev Mol Cell Biol 2011; 12:656-68. [PMID: 21941275 DOI: 10.1038/nrm3199] [Citation(s) in RCA: 96] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Proteins are always on the move, and this may occur through diffusion or active transport. The realization that the regulation of signal transduction is highly dynamic in space and time has stimulated intense interest in the movement of proteins. Over the past decade, numerous new technologies using fluorescent proteins have been developed, allowing us to observe the spatiotemporal dynamics of proteins in living cells. These technologies have greatly advanced our understanding of protein dynamics, including protein movement and protein interactions.
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12
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McKinney MC, Stark DA, Teddy J, Kulesa PM. Neural crest cell communication involves an exchange of cytoplasmic material through cellular bridges revealed by photoconversion of KikGR. Dev Dyn 2011; 240:1391-401. [PMID: 21472890 DOI: 10.1002/dvdy.22612] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/19/2011] [Indexed: 11/07/2022] Open
Abstract
Neural crest (NC) cells invade the vertebrate embryo in ordered migratory streams, yet it is unclear whether cells communicate to maintain spacing and direction. Here, we examined NC cell communication in detail, using optical highlighting and photobleaching to monitor cell contact dynamics. We observed cytoplasmic transfer between NC cell neighbors through thin cellular bridges. The transfer of molecules between NC cells was bi-directional, not at equal rates, and independent of bridge dynamics. The cytoplasmic transfer was prevalent in recently divided NC cells. Molecular simulations, based on Brownian motion and measured cell volumes, predicted that simple diffusion could not account for observed cytoplasmic transfer rates. Cell tracking revealed that exchange of cytoplasmic material preceded the re-orientation of cells to the direction of migration. Our data suggest a mechanism by which NC cells communicate position information through the formation of cellular bridges that allow exchange of cytoplasmic material through active transport.
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13
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Conyard J, Kondo M, Heisler IA, Jones G, Baldridge A, Tolbert LM, Solntsev KM, Meech SR. Chemically modulating the photophysics of the GFP chromophore. J Phys Chem B 2011; 115:1571-7. [PMID: 21268624 DOI: 10.1021/jp111593x] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
There is growing interest in engineering the properties of fluorescent proteins through modifications to the chromophore structure utilizing mutagenesis with either natural or unnatural amino acids. This entails an understanding of the photophysical and photochemical properties of the modified chromophore. In this work, a range of GFP chromophores with different alkyl substituents are synthesized and their electronic spectra, pH dependence, and ultrafast fluorescence decay kinetics are investigated. The weakly electron donating character of the alkyl substituents leads to dramatic red shifts in the electronic spectra of the anions, which are accompanied by increased fluorescence decay times. This high sensitivity of electronic structure to substitution is also characteristic of some fluorescent proteins. The solvent viscosity dependence of the decay kinetics are investigated, and found to be consistent with a bimodal radiationless relaxation coordinate. Some substituents are shown to distort the planar structure of the chromophore, which results in a blue shift in the electronic spectra and a strong enhancement of the radiationless decay. The significance of these data for the rational design of novel fluorescent proteins is discussed.
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Affiliation(s)
- Jamie Conyard
- School of Chemistry, University of East Anglia, Norwich NR4 7TJ, United Kingdom
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14
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Peters R. Regaining eukaryotic identity after cell division: relax, young cell. Biophys J 2009; 97:1809-10. [PMID: 19804710 DOI: 10.1016/j.bpj.2009.07.023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2009] [Revised: 07/26/2009] [Accepted: 07/29/2009] [Indexed: 10/20/2022] Open
Affiliation(s)
- Reiner Peters
- The Rockefeller University, Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, New York, New York, USA.
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