1
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Boto T, Tomchik SM. Functional Imaging of Learning-Induced Plasticity in the Central Nervous System with Genetically Encoded Reporters in Drosophila. Cold Spring Harb Protoc 2024; 2024:pdb.top107799. [PMID: 37197830 DOI: 10.1101/pdb.top107799] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Learning and memory allow animals to adjust their behavior based on the predictive value of their past experiences. Memories often exist in complex representations, spread across numerous cells and synapses in the brain. Studying relatively simple forms of memory provides insights into the fundamental processes that underlie multiple forms of memory. Associative learning occurs when an animal learns the relationship between two previously unrelated sensory stimuli, such as when a hungry animal learns that a particular odor is followed by a tasty reward. Drosophila is a particularly powerful model to study how this type of memory works. The fundamental principles are widely shared among animals, and there is a wide range of genetic tools available to study circuit function in flies. In addition, the olfactory structures that mediate associative learning in flies, such as the mushroom body and its associated neurons, are anatomically organized, relatively well-characterized, and readily accessible to imaging. Here, we review the olfactory anatomy and physiology of the olfactory system, describe how plasticity in the olfactory pathway mediates learning and memory, and explain the general principles underlying calcium imaging approaches.
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Affiliation(s)
- Tamara Boto
- Department of Physiology, Trinity College Dublin, Dublin 2, Ireland
- Trinity College Institute of Neuroscience, Trinity College Dublin, Dublin 2, Ireland
| | - Seth M Tomchik
- Neuroscience and Pharmacology, University of Iowa Carver College of Medicine, Iowa City, Iowa 52242, USA
- Stead Family Department of Pediatrics, University of Iowa Carver College of Medicine, Iowa City, Iowa 52242, USA
- Iowa Neuroscience Institute, University of Iowa Carver College of Medicine, Iowa City, Iowa 52242, USA
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2
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Ahmad M, Movileanu L. Multiplexed imaging for probing RAS-RAF interactions in living cells. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2023; 1865:184173. [PMID: 37211322 PMCID: PMC10330472 DOI: 10.1016/j.bbamem.2023.184173] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Revised: 04/18/2023] [Accepted: 05/08/2023] [Indexed: 05/23/2023]
Abstract
GTP-bound RAS interacts with its protein effectors in response to extracellular stimuli, leading to chemical inputs for downstream pathways. Significant progress has been made in measuring these reversible protein-protein interactions (PPIs) in various cell-free environments. Yet, acquiring high sensitivity in heterogeneous solutions remains challenging. Here, using an intermolecular fluorescence resonance energy transfer (FRET) biosensing approach, we develop a method to visualize and localize HRAS-CRAF interactions in living cells. We demonstrate that the EGFR activation and the HRAS-CRAF complex formation can be concurrently probed in a single cell. This biosensing strategy discriminates EGF-stimulated HRAS-CRAF interactions at the cell and organelle membranes. In addition, we provide quantitative FRET measurements for assessing these transient PPIs in a cell-free environment. Finally, we prove the utility of this approach by showing that an EGFR-binding compound is a potent inhibitor of HRAS-CRAF interactions. The outcomes of this work form a fundamental basis for further explorations of the spatiotemporal dynamics of various signaling networks.
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Affiliation(s)
- Mohammad Ahmad
- Department of Physics, Syracuse University, 201 Physics Building, Syracuse, New York 13244-1130, USA
| | - Liviu Movileanu
- Department of Physics, Syracuse University, 201 Physics Building, Syracuse, New York 13244-1130, USA; Department of Biomedical and Chemical Engineering, Syracuse University, 329 Link Hall, Syracuse, NY 13244, USA; The BioInspired Institute, Syracuse University, Syracuse, NY 13244, USA.
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3
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Wu YW. Spatiotemporal Imaging of Small GTPase Activity Using Conformational Sensors for GTPase Activity (COSGA). METHODS IN MOLECULAR BIOLOGY (CLIFTON, N.J.) 2021; 2262:259-267. [PMID: 33977482 DOI: 10.1007/978-1-0716-1190-6_15] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Small GTPases cycle between active GTP bound and inactive GDP bound forms in live cells. They act as molecular switches and regulate diverse cellular processes at different times and locations in the cell. Spatiotemporal visualization of their activity provides important insights into dynamics of cellular signaling. Conformational sensors for GTPase activity (COSGAs) are based on the conserved GTPase fold and have been used as a versatile approach for imaging small GTPase activity in the cell. Conformational changes upon GDP/GTP binding can be visualized directly in solution, on beads, or in live cells using COSGA by fluorescence lifetime imaging microscopy (FLIM) technique. Herein, we describe the construction of COSGA for imaging K-Ras GTPase activity in live cells.
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Affiliation(s)
- Yao-Wen Wu
- Department of Chemistry, Umeå Centre for Microbial Research, Umeå University, Umeå, Sweden.
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4
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Lauri A, Fasano G, Venditti M, Dallapiccola B, Tartaglia M. In vivo Functional Genomics for Undiagnosed Patients: The Impact of Small GTPases Signaling Dysregulation at Pan-Embryo Developmental Scale. Front Cell Dev Biol 2021; 9:642235. [PMID: 34124035 PMCID: PMC8194860 DOI: 10.3389/fcell.2021.642235] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Accepted: 03/12/2021] [Indexed: 12/24/2022] Open
Abstract
While individually rare, disorders affecting development collectively represent a substantial clinical, psychological, and socioeconomic burden to patients, families, and society. Insights into the molecular mechanisms underlying these disorders are required to speed up diagnosis, improve counseling, and optimize management toward targeted therapies. Genome sequencing is now unveiling previously unexplored genetic variations in undiagnosed patients, which require functional validation and mechanistic understanding, particularly when dealing with novel nosologic entities. Functional perturbations of key regulators acting on signals' intersections of evolutionarily conserved pathways in these pathological conditions hinder the fine balance between various developmental inputs governing morphogenesis and homeostasis. However, the distinct mechanisms by which these hubs orchestrate pathways to ensure the developmental coordinates are poorly understood. Integrative functional genomics implementing quantitative in vivo models of embryogenesis with subcellular precision in whole organisms contribute to answering these questions. Here, we review the current knowledge on genes and mechanisms critically involved in developmental syndromes and pediatric cancers, revealed by genomic sequencing and in vivo models such as insects, worms and fish. We focus on the monomeric GTPases of the RAS superfamily and their influence on crucial developmental signals and processes. We next discuss the effectiveness of exponentially growing functional assays employing tractable models to identify regulatory crossroads. Unprecedented sophistications are now possible in zebrafish, i.e., genome editing with single-nucleotide precision, nanoimaging, highly resolved recording of multiple small molecules activity, and simultaneous monitoring of brain circuits and complex behavioral response. These assets permit accurate real-time reporting of dynamic small GTPases-controlled processes in entire organisms, owning the potential to tackle rare disease mechanisms.
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Affiliation(s)
- Antonella Lauri
- Genetics and Rare Diseases Research Division, Ospedale Pediatrico Bambino Gesù, IRCCS, Rome, Italy
| | | | | | | | - Marco Tartaglia
- Genetics and Rare Diseases Research Division, Ospedale Pediatrico Bambino Gesù, IRCCS, Rome, Italy
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5
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Samanta D, Ebrahimi SB, Mirkin CA. Nucleic-Acid Structures as Intracellular Probes for Live Cells. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2020; 32:e1901743. [PMID: 31271253 PMCID: PMC6942251 DOI: 10.1002/adma.201901743] [Citation(s) in RCA: 93] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Revised: 05/08/2019] [Indexed: 05/02/2023]
Abstract
The chemical composition of cells at the molecular level determines their growth, differentiation, structure, and function. Probing this composition is powerful because it provides invaluable insight into chemical processes inside cells and in certain cases allows disease diagnosis based on molecular profiles. However, many techniques analyze fixed cells or lysates of bulk populations, in which information about dynamics and cellular heterogeneity is lost. Recently, nucleic-acid-based probes have emerged as a promising platform for the detection of a wide variety of intracellular analytes in live cells with single-cell resolution. Recent advances in this field are described and common strategies for probe design, types of targets that can be identified, current limitations, and future directions are discussed.
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Affiliation(s)
- Devleena Samanta
- Department of Chemistry and International Institute for Nanotechnology, Northwestern University, 2145 Sheridan Road, Evanston, IL, 60208, USA
| | - Sasha B Ebrahimi
- Department of Chemical and Biological Engineering, Northwestern University, 2145 Sheridan Road, Evanston, IL, 60208, USA
| | - Chad A Mirkin
- Department of Chemistry and International Institute for Nanotechnology, Northwestern University, 2145 Sheridan Road, Evanston, IL, 60208, USA
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6
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Li FY, Zhang ZF, Voss S, Wu YW, Zhao YF, Li YM, Chen YX. Inhibition of K-Ras4B-plasma membrane association with a membrane microdomain-targeting peptide. Chem Sci 2019; 11:826-832. [PMID: 34123058 PMCID: PMC8145430 DOI: 10.1039/c9sc04726c] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The association of K-Ras4B protein with plasma membrane (PM) is required for its signaling activity. Thus, direct inhibition of K-Ras4B–PM interaction could be a potential anti-Ras therapeutic strategy. However, it remains challenging to modulate such protein–PM interaction. Based on Ras isoform-specific PM microdomain localization patterns, we have developed a potent and isoform-selective peptide inhibitor, Memrasin, for detachment of K-Ras4B from the PM. Memrasin is one of the first direct inhibitors of K-Ras4B–PM interaction, and consists of a membrane ld region-binding sequence derived from the C-terminal region of K-Ras4B and an endosome-escape enhancing motif that can aggregate on membrane. It forms peptide-enriched domains in the ld region, abrogates the tethering of K-Ras4B to the PM and accordingly impairs Ras signaling activity, thereby efficiently decreasing the viability of several human lung cancer cells in a dose-responsive and K-Ras dependent manner. Memrasin provides a useful tool for exploring the biological function of K-Ras4B on or off the PM and a potential starting point for further development into anti-Ras therapeutics. A membrane ld microdomain-targeting hybrid peptide displays potent inhibition effect toward K-Ras4B-plasma membrane interaction and impairs Ras signaling output.![]()
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Affiliation(s)
- Fang-Yi Li
- Key Laboratory of Bioorganic Phosphorus Chemistry and Chemical Biology (Ministry of Education), Department of Chemistry, Tsinghua University Beijing 100084 China
| | - Zhen-Feng Zhang
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences No. 1 West Beichen Road, Chaoyang District Beijing 100101 China
| | - Stephanie Voss
- Chemical Genomics Centre of the Max Planck Society Otto-Hahn-Str. 15 44227 Dortmund Germany.,Max-Planck-Institute of Molecular Physiology Otto-Hahn-Str. 11 44227 Dortmund Germany
| | - Yao-Wen Wu
- Chemical Genomics Centre of the Max Planck Society Otto-Hahn-Str. 15 44227 Dortmund Germany.,Max-Planck-Institute of Molecular Physiology Otto-Hahn-Str. 11 44227 Dortmund Germany.,Department of Chemistry, Umeå University 90187 Umeå Sweden
| | - Yu-Fen Zhao
- Key Laboratory of Bioorganic Phosphorus Chemistry and Chemical Biology (Ministry of Education), Department of Chemistry, Tsinghua University Beijing 100084 China
| | - Yan-Mei Li
- Key Laboratory of Bioorganic Phosphorus Chemistry and Chemical Biology (Ministry of Education), Department of Chemistry, Tsinghua University Beijing 100084 China
| | - Yong-Xiang Chen
- Key Laboratory of Bioorganic Phosphorus Chemistry and Chemical Biology (Ministry of Education), Department of Chemistry, Tsinghua University Beijing 100084 China
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7
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Alex A, Piano V, Polley S, Stuiver M, Voss S, Ciossani G, Overlack K, Voss B, Wohlgemuth S, Petrovic A, Wu Y, Selenko P, Musacchio A, Maffini S. Electroporated recombinant proteins as tools for in vivo functional complementation, imaging and chemical biology. eLife 2019; 8:48287. [PMID: 31310234 PMCID: PMC6656429 DOI: 10.7554/elife.48287] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Accepted: 07/12/2019] [Indexed: 02/06/2023] Open
Abstract
Delivery of native or chemically modified recombinant proteins into mammalian cells shows promise for functional investigations and various technological applications, but concerns that sub-cellular localization and functional integrity of delivered proteins may be affected remain high. Here, we surveyed batch electroporation as a delivery tool for single polypeptides and multi-subunit protein assemblies of the kinetochore, a spatially confined and well-studied subcellular structure. After electroporation into human cells, recombinant fluorescent Ndc80 and Mis12 multi-subunit complexes exhibited native localization, physically interacted with endogenous binding partners, and functionally complemented depleted endogenous counterparts to promote mitotic checkpoint signaling and chromosome segregation. Farnesylation is required for kinetochore localization of the Dynein adaptor Spindly. In cells with chronically inhibited farnesyl transferase activity, in vitro farnesylation and electroporation of recombinant Spindly faithfully resulted in robust kinetochore localization. Our data show that electroporation is well-suited to deliver synthetic and chemically modified versions of functional proteins, and, therefore, constitutes a promising tool for applications in chemical and synthetic biology.
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Affiliation(s)
- Amal Alex
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | - Valentina Piano
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | - Soumitra Polley
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | - Marchel Stuiver
- In-Cell NMR Laboratory, Leibniz Institute of Molecular Pharmacology (FMP Berlin), Berlin, Germany
| | - Stephanie Voss
- Chemical Genomics Centre, Max Planck Society, Dortmund, Germany
| | - Giuseppe Ciossani
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | - Katharina Overlack
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | - Beate Voss
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | - Sabine Wohlgemuth
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | - Arsen Petrovic
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | - Yaowen Wu
- Chemical Genomics Centre, Max Planck Society, Dortmund, Germany.,Department of Chemistry, Umeå University, Umeå, Sweden
| | - Philipp Selenko
- In-Cell NMR Laboratory, Leibniz Institute of Molecular Pharmacology (FMP Berlin), Berlin, Germany.,Department of Biological Regulation, Weizmann Institute of Science, Rehovot, Israel
| | - Andrea Musacchio
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Dortmund, Germany.,Centre for Medical Biotechnology, Faculty of Biology, University Duisburg-Essen, Essen, Germany
| | - Stefano Maffini
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Dortmund, Germany
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8
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Voss S, Li F, Rätz A, Röger M, Wu YW. Spatial Cycling of Rab GTPase, Driven by the GTPase Cycle, Controls Rab's Subcellular Distribution. Biochemistry 2019; 58:276-285. [PMID: 30605611 DOI: 10.1021/acs.biochem.8b00932] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Rab GTPases (>60 members in humans) function as master regulators of intracellular membrane trafficking. Correct and specific localization of Rab proteins is required for their function. How the distinct spatial distribution of Rab GTPases in the cell is regulated remains elusive. To globally assess the subcellular localization of Rab1, we determined kinetic parameters of two pathways that control the spatial cycles of Rab1, i.e., vesicular transport and GDP dissociation inhibitor (GDI)-mediated recycling. We demonstrate that the switching between GTP and GDP binding states, which is governed by guanine nucleotide exchange factors (GEFs), GTPase-activating proteins (GAPs), GDI, and GDI displacement factor (GDF), is a major determinant of Rab1's ability to effectively cycle between cellular compartments and eventually its subcellular distribution. In silico perturbations of vesicular transport, GEFs, GAPs, GDI, and GDF using a mathematical model with simplified cellular geometries showed that these regulators play an important role in the subcellular distribution and activity of Rab1.
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Affiliation(s)
- Stephanie Voss
- Chemical Genomics Centre of the Max Planck Society , Otto-Hahn-Strasse 15 , 44227 Dortmund , Germany.,Max-Planck-Institute of Molecular Physiology , Otto-Hahn-Strasse 11 , 44227 Dortmund , Germany
| | - Fu Li
- Chemical Genomics Centre of the Max Planck Society , Otto-Hahn-Strasse 15 , 44227 Dortmund , Germany.,Max-Planck-Institute of Molecular Physiology , Otto-Hahn-Strasse 11 , 44227 Dortmund , Germany.,Department of Chemistry, Umeå Centre for Microbial Research , Umeå University , 90187 Umeå , Sweden
| | - Andreas Rätz
- TU Dortmund University , Faculty of Mathematics , Vogelpothsweg 87 , 44227 Dortmund , Germany
| | - Matthias Röger
- TU Dortmund University , Faculty of Mathematics , Vogelpothsweg 87 , 44227 Dortmund , Germany
| | - Yao-Wen Wu
- Chemical Genomics Centre of the Max Planck Society , Otto-Hahn-Strasse 15 , 44227 Dortmund , Germany.,Max-Planck-Institute of Molecular Physiology , Otto-Hahn-Strasse 11 , 44227 Dortmund , Germany.,Department of Chemistry, Umeå Centre for Microbial Research , Umeå University , 90187 Umeå , Sweden
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9
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Generation of Intramolecular FRET Probes via Noncanonical Amino Acid Mutagenesis. Methods Mol Biol 2018. [PMID: 29405008 DOI: 10.1007/978-1-4939-7574-7_21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
Förster resonance energy transfer (FRET) probes are powerful tools to monitor protein-protein interactions and enzyme activities in a spatiotemporal manner in live cells. Using a combination of noncanonical amino acid (ncAA) mutagenesis and bioorthogonal labeling, we have developed intramolecular FRET probes consisting of a fluorescent protein and an organic dye within an individual protein. Herein we present a general approach to establish intramolecular FRET probes for imaging of protein activity in live cells.
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10
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Nguyen B, Hartich D, Seifert U, Rios PDL. Thermodynamic Bounds on the Ultra- and Infra-affinity of Hsp70 for Its Substrates. Biophys J 2017; 113:362-370. [PMID: 28746847 DOI: 10.1016/j.bpj.2017.06.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Revised: 05/31/2017] [Accepted: 06/09/2017] [Indexed: 12/16/2022] Open
Abstract
The 70 kDa heat shock protein Hsp70 has several essential functions in living systems, such as protecting cells against protein aggregation, assisting protein folding, remodeling protein complexes, and driving translocation into organelles. These functions require high affinity for nonspecific amino acid sequences that are ubiquitous in proteins. It has been recently shown that this high affinity, called ultra-affinity, depends on a process driven out of equilibrium by ATP hydrolysis. Here, we establish the thermodynamic bounds for ultra-affinity, and further show that the same reaction scheme can in principle be used both to strengthen and to weaken affinities (leading in this case to infra-affinity). We show that cofactors are essential to achieve affinity beyond the equilibrium range. Finally, biological implications are discussed.
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Affiliation(s)
- Basile Nguyen
- II. Institut für Theoretische Physik, Universität Stuttgart, Stuttgart, Germany; Laboratory of Statistical Biophysics, Institute of Physics, School of Basic Science and Institute of Bioengineering, School of Life Sciences, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland.
| | - David Hartich
- II. Institut für Theoretische Physik, Universität Stuttgart, Stuttgart, Germany
| | - Udo Seifert
- II. Institut für Theoretische Physik, Universität Stuttgart, Stuttgart, Germany
| | - Paolo De Los Rios
- Laboratory of Statistical Biophysics, Institute of Physics, School of Basic Science and Institute of Bioengineering, School of Life Sciences, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
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11
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Abstract
All cellular behaviors arise through the coordinated actions of numerous intracellular biochemical pathways. Over the past 20 years, efforts to probe intracellular biochemical processes have undergone a fundamental transformation brought about by advances in fluorescence imaging, such as the development of genetically encoded fluorescent reporters and new imaging technologies; the impact of these approaches on our understanding of the molecular underpinnings of biological function cannot be understated. In particular, the ability to obtain information on the spatiotemporal regulation of biochemical processes unfolding in real time in the native context of a living cell has crystallized the view, long a matter of speculation, that cells achieve specific biological outcomes through the imposition of spatial control over the distribution of various biomolecules, and their associated biochemical activities, within the cellular environment. Indeed, the compartmentalization of biochemical activities by cells is now known to be pervasive and to span a multitude of spatial scales, from the length of a cell to just a few enzymes. In this Perspective, part of this special issue on "Seeing into cells", we highlight several recent imaging studies that provide detailed insights into not just where molecules are but where molecules are active within cells, offering a glimpse into the emerging view of biochemical activity architecture as a complement to the physical architecture of a cell.
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Affiliation(s)
- Sohum Mehta
- Department of Pharmacology, University of California, San Diego , La Jolla, California 92093, United States
| | - Jin Zhang
- Department of Pharmacology, University of California, San Diego , La Jolla, California 92093, United States.,Department of Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine , Baltimore, Maryland 21205, United States
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