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Wang J, Platz-Baudin E, Noetzel E, Offenhäusser A, Maybeck V. Expressing Optogenetic Actuators Fused to N-terminal Mucin Motifs Delivers Targets to Specific Subcellular Compartments in Polarized Cells. Adv Biol (Weinh) 2024; 8:e2300428. [PMID: 38015104 DOI: 10.1002/adbi.202300428] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Revised: 10/31/2023] [Indexed: 11/29/2023]
Abstract
Optogenetics is a powerful approach in neuroscience research. However, other tissues of the body may benefit from controlled ion currents and neuroscience may benefit from more precise optogenetic expression. The present work constructs three subcellularly-targeted optogenetic actuators based on the channelrhodopsin ChR2-XXL, utilizing 5, 10, or 15 tandem repeats (TR) from mucin as N-terminal targeting motifs and evaluates expression in several polarized and non-polarized cell types. The modified channelrhodopsin maintains its electrophysiological properties, which can be used to produce continuous membrane depolarization, despite the expected size of the repeats. This work then shows that these actuators are subcellularly localized in polarized cells. In polarized epithelial cells, all three actuators localize to just the lateral membrane. The TR-tagged constructs also express subcellularly in cortical neurons, where TR5-ChR2XXL and TR10-ChR2XXL mainly target the somatodendrites. Moreover, the transfection efficiencies are shown to be dependent on cell type and tandem repeat length. Overall, this work verifies that the targeting motifs from epithelial cells can be used to localize optogenetic actuators in both epithelia and neurons, opening epithelia processes to optogenetic manipulation and providing new possibilities to target optogenetic tools.
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Affiliation(s)
- Jiali Wang
- Institute of Biological Information Processing IBI-3, Forschungszentrum Jülich GmbH, 52428, Jülich, Germany
- Faculty of Mathematics, Computer Science and Natural Sciences, RWTH Aachen University, 52062, Aachen, Germany
| | - Eric Platz-Baudin
- Institute of Biological Information Processing IBI-2, Forschungszentrum Jülich GmbH, 52428, Jülich, Germany
| | - Erik Noetzel
- Institute of Biological Information Processing IBI-2, Forschungszentrum Jülich GmbH, 52428, Jülich, Germany
| | - Andreas Offenhäusser
- Institute of Biological Information Processing IBI-3, Forschungszentrum Jülich GmbH, 52428, Jülich, Germany
- Faculty of Mathematics, Computer Science and Natural Sciences, RWTH Aachen University, 52062, Aachen, Germany
| | - Vanessa Maybeck
- Institute of Biological Information Processing IBI-3, Forschungszentrum Jülich GmbH, 52428, Jülich, Germany
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2
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Costa ISD, Junot T, Silva FL, Felix W, Cardozo Fh JL, Pereira de Araujo AF, Pais do Amaral C, Gonçalves S, Santos NC, Leite JRSA, Bloch C, Brand GD. Occurrence and evolutionary conservation analysis of α-helical cationic amphiphilic segments in the human proteome. FEBS J 2024; 291:547-565. [PMID: 37945538 DOI: 10.1111/febs.16997] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Revised: 09/14/2023] [Accepted: 10/20/2023] [Indexed: 11/12/2023]
Abstract
The existence of encrypted fragments with antimicrobial activity in human proteins has been thoroughly demonstrated in the literature. Recently, algorithms for the large-scale identification of these segments in whole proteomes were developed, and the pervasiveness of this phenomenon was stated. These algorithms typically mine encrypted cationic and amphiphilic segments of proteins, which, when synthesized as individual polypeptide sequences, exert antimicrobial activity by membrane disruption. In the present report, the human reference proteome was submitted to the software kamal for the uncovering of protein segments that correspond to putative intragenic antimicrobial peptides (IAPs). The assessment of the identity of these segments, frequency, functional classes of parent proteins, structural relevance, and evolutionary conservation of amino acid residues within their corresponding proteins was conducted in silico. Additionally, the antimicrobial and anticancer activity of six selected synthetic peptides was evaluated. Our results indicate that cationic and amphiphilic segments can be found in 2% of all human proteins, but are more common in transmembrane and peripheral membrane proteins. These segments are surface-exposed basic patches whose amino acid residues present similar conservation scores to other residues with similar solvent accessibility. Moreover, the antimicrobial and anticancer activity of the synthetic putative IAP sequences was irrespective to whether these are associated to membranes in the cellular setting. Our study discusses these findings in light of the current understanding of encrypted peptide sequences, offering some insights into the relevance of these segments to the organism in the context of their harboring proteins or as separate polypeptide sequences.
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Affiliation(s)
- Igor S D Costa
- Laboratório de Síntese e Análise de Biomoléculas - LSAB, Instituto de Química, Universidade de Brasília, Brazil
| | - Tiago Junot
- Laboratório de Síntese e Análise de Biomoléculas - LSAB, Instituto de Química, Universidade de Brasília, Brazil
| | - Fernanda L Silva
- Laboratório de Síntese e Análise de Biomoléculas - LSAB, Instituto de Química, Universidade de Brasília, Brazil
| | - Wanessa Felix
- Núcleo de Pesquisa em Morfologia e Imunologia Aplicada - NuPMIA, Faculdade de Medicina, Universidade de Brasília, Brazil
| | - José L Cardozo Fh
- Laboratório de Espectrometria de Massa - LEM, Embrapa Recursos Genéticos e Biotecnologia, Brasília, Brazil
| | - Antonio F Pereira de Araujo
- Laboratório de Biofísica Teórica e Computacional, Departamento de Biologia Celular, Universidade de Brasília, Brazil
| | | | - Sónia Gonçalves
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Portugal
| | - Nuno C Santos
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Portugal
| | - José R S A Leite
- Núcleo de Pesquisa em Morfologia e Imunologia Aplicada - NuPMIA, Faculdade de Medicina, Universidade de Brasília, Brazil
| | - Carlos Bloch
- Laboratório de Espectrometria de Massa - LEM, Embrapa Recursos Genéticos e Biotecnologia, Brasília, Brazil
| | - Guilherme D Brand
- Laboratório de Síntese e Análise de Biomoléculas - LSAB, Instituto de Química, Universidade de Brasília, Brazil
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Chioccioli Altadonna G, Montalbano A, Iorio J, Becchetti A, Arcangeli A, Duranti C. The Interaction between hERG1 and β1 Integrins Modulates hERG1 Current in Different Pathological Cell Models. MEMBRANES 2022; 12:1162. [PMID: 36422154 PMCID: PMC9698864 DOI: 10.3390/membranes12111162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/08/2022] [Revised: 11/13/2022] [Accepted: 11/16/2022] [Indexed: 06/16/2023]
Abstract
Ion channels are implicated in various diseases, including cancer, in which they modulate different aspects of cancer progression. In particular, potassium channels are often aberrantly expressed in cancers, a major example being provided by hERG1. The latter is generally complexed with β1 integrin in tumour cells, and such a molecular complex represents a new druggable hub. The present study focuses on the characterization of the functional consequences of the interaction between hERG1 and β1 integrins on different substrates over time. To this purpose, we studied the interplay alteration on the plasma membrane through patch clamp techniques in a cellular model consisting of human embryonic kidney (HEK) cells stably transfected with hERG1 and in a cancer cell model consisting of SH-SY5Y neuroblastoma cells, endogenously expressing the channel. Cells were seeded on different substrates known to stimulate β1 integrins, such as fibronectin (FN) for HEK-hERG1 and laminin (LMN) for SH-SY5Y. In HEK cells stably overexpressing hERG1, we observed a hERG1 current density increase accompanied by Vrest hyperpolarization after cell seeding onto FN. Notably, a similar behaviour was shown by SH-SY5Y neuroblastoma cells plated onto LMN. Interestingly, we did not observe this phenomenon when plating the cells on substrates such as Bovine Serum Albumin (BSA) or Polylysine (PL), thus suggesting a crucial involvement of ECM proteins as well as of β1 integrin activation.
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Affiliation(s)
| | - Alberto Montalbano
- Department of Experimental and Clinical Medicine, University of Firenze, Viale G.B. Morgagni 50, 50134 Firenze, Italy
| | - Jessica Iorio
- Department of Experimental and Clinical Medicine, University of Firenze, Viale G.B. Morgagni 50, 50134 Firenze, Italy
| | - Andrea Becchetti
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, Piazza della Scienza 2, 20126 Milano, Italy
| | - Annarosa Arcangeli
- Department of Experimental and Clinical Medicine, University of Firenze, Viale G.B. Morgagni 50, 50134 Firenze, Italy
| | - Claudia Duranti
- Department of Experimental and Clinical Medicine, University of Firenze, Viale G.B. Morgagni 50, 50134 Firenze, Italy
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4
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de Coene Y, Jooken S, Deschaume O, Van Steenbergen V, Vanden Berghe P, Van den Haute C, Baekelandt V, Callewaert G, Van Cleuvenbergen S, Verbiest T, Bartic C, Clays K. Label-Free Imaging of Membrane Potentials by Intramembrane Field Modulation, Assessed by Second Harmonic Generation Microscopy. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2022; 18:e2200205. [PMID: 35355419 DOI: 10.1002/smll.202200205] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Revised: 03/03/2022] [Indexed: 06/14/2023]
Abstract
Optical interrogation of cellular electrical activity has proven itself essential for understanding cellular function and communication in complex networks. Voltage-sensitive dyes are important tools for assessing excitability but these highly lipophilic sensors may affect cellular function. Label-free techniques offer a major advantage as they eliminate the need for these external probes. In this work, it is shown that endogenous second-harmonic generation (SHG) from live cells is highly sensitive to changes in transmembrane potential (TMP). Simultaneous electrophysiological control of a living human embryonic kidney (HEK293T) cell, through a whole-cell voltage-clamp reveals a linear relation between the SHG intensity and membrane voltage. The results suggest that due to the high ionic strengths and fast optical response of biofluids, membrane hydration is not the main contributor to the observed field sensitivity. A conceptual framework is further provided that indicates that the SHG voltage sensitivity reflects the electric field within the biological asymmetric lipid bilayer owing to a nonzero χeff(2) tensor. Changing the TMP without surface modifications such as electrolyte screening offers high optical sensitivity to membrane voltage (≈40% per 100 mV), indicating the power of SHG for label-free read-out. These results hold promise for the design of a non-invasive label-free read-out tool for electrogenic cells.
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Affiliation(s)
- Yovan de Coene
- Laboratory of Molecular Imaging and Photonics, Department of Chemistry, KU Leuven, Celestijnenlaan 200D, Leuven, 3001, Belgium
| | - Stijn Jooken
- Laboratory of Soft Matter and Biophysics, Department of Physics and Astronomy, KU Leuven, Celestijnenlaan 200D, Leuven, 3001, Belgium
| | - Olivier Deschaume
- Laboratory of Soft Matter and Biophysics, Department of Physics and Astronomy, KU Leuven, Celestijnenlaan 200D, Leuven, 3001, Belgium
| | - Valérie Van Steenbergen
- Laboratory for Enteric NeuroScience (LENS), TAGRID, Department of Chronic Diseases Metabolism and Ageing, Ku Leuven, ON I Herestraat 49, Leuven, 3000, Belgium
| | - Pieter Vanden Berghe
- Laboratory for Enteric NeuroScience (LENS), TAGRID, Department of Chronic Diseases Metabolism and Ageing, Ku Leuven, ON I Herestraat 49, Leuven, 3000, Belgium
| | - Chris Van den Haute
- Laboratory for Neurobiology and Gene Therapy, Department of Neurosciences, Ku Leuven, RK-Herestraat 49, Leuven, 3000, Belgium
| | - Veerle Baekelandt
- Laboratory for Neurobiology and Gene Therapy, Department of Neurosciences, Ku Leuven, RK-Herestraat 49, Leuven, 3000, Belgium
| | - Geert Callewaert
- Department of Cellular and Molecular Medicine, Ku Leuven, KULAK Kortrijk Campus, Etienne Sabbelaan 53, Kortrijk, 8500, Belgium
| | - Stijn Van Cleuvenbergen
- Laboratory of Molecular Imaging and Photonics, Department of Chemistry, KU Leuven, Celestijnenlaan 200D, Leuven, 3001, Belgium
| | - Thierry Verbiest
- Laboratory of Molecular Imaging and Photonics, Department of Chemistry, KU Leuven, Celestijnenlaan 200D, Leuven, 3001, Belgium
| | - Carmen Bartic
- Laboratory of Soft Matter and Biophysics, Department of Physics and Astronomy, KU Leuven, Celestijnenlaan 200D, Leuven, 3001, Belgium
| | - Koen Clays
- Laboratory of Molecular Imaging and Photonics, Department of Chemistry, KU Leuven, Celestijnenlaan 200D, Leuven, 3001, Belgium
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5
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Daria VR, Castañares ML, Bachor HA. Spatio-temporal parameters for optical probing of neuronal activity. Biophys Rev 2021; 13:13-33. [PMID: 33747244 PMCID: PMC7930150 DOI: 10.1007/s12551-021-00780-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2020] [Accepted: 01/01/2021] [Indexed: 12/28/2022] Open
Abstract
The challenge to understand the complex neuronal circuit functions in the mammalian brain has brought about a revolution in light-based neurotechnologies and optogenetic tools. However, while recent seminal works have shown excellent insights on the processing of basic functions such as sensory perception, memory, and navigation, understanding more complex brain functions is still unattainable with current technologies. We are just scratching the surface, both literally and figuratively. Yet, the path towards fully understanding the brain is not totally uncertain. Recent rapid technological advancements have allowed us to analyze the processing of signals within dendritic arborizations of single neurons and within neuronal circuits. Understanding the circuit dynamics in the brain requires a good appreciation of the spatial and temporal properties of neuronal activity. Here, we assess the spatio-temporal parameters of neuronal responses and match them with suitable light-based neurotechnologies as well as photochemical and optogenetic tools. We focus on the spatial range that includes dendrites and certain brain regions (e.g., cortex and hippocampus) that constitute neuronal circuits. We also review some temporal characteristics of some proteins and ion channels responsible for certain neuronal functions. With the aid of the photochemical and optogenetic markers, we can use light to visualize the circuit dynamics of a functioning brain. The challenge to understand how the brain works continue to excite scientists as research questions begin to link macroscopic and microscopic units of brain circuits.
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Affiliation(s)
- Vincent R. Daria
- Research School of Physics, The Australian National University, Canberra, Australia
- John Curtin School of Medical Research, The Australian National University, Canberra, Australia
| | | | - Hans-A. Bachor
- Research School of Physics, The Australian National University, Canberra, Australia
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6
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Eisenberg S, Haimov E, Walpole GFW, Plumb J, Kozlov MM, Grinstein S. Mapping the electrostatic profiles of cellular membranes. Mol Biol Cell 2020; 32:301-310. [PMID: 33263429 PMCID: PMC8098824 DOI: 10.1091/mbc.e19-08-0436] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Anionic phospholipids can confer a net negative charge on biological membranes. This surface charge generates an electric field that serves to recruit extrinsic cationic proteins, can alter the disposition of transmembrane proteins and causes the local accumulation of soluble counterions, altering the local pH and the concentration of physiologically important ions such as calcium. Because the phospholipid compositions of the different organellar membranes vary, their surface charges are similarly expected to diverge. Yet, despite the important functional implications, remarkably little is known about the electrostatic properties of the individual organellar membranes. We therefore designed and implemented approaches to estimate the surface charges of the cytosolic membranes of various organelles in situ in intact cells. Our data indicate that the inner leaflet of the plasma membrane is most negative, with a surface potential of approximately –35 mV, followed by the Golgi complex > lysosomes > mitochondria ≈ peroxisomes > endoplasmic reticulum, in decreasing order.
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Affiliation(s)
- Sharon Eisenberg
- Program in Cell Biology, Hospital for Sick Children, 686 Bay Street, Toronto, ON, Canada M5G 0A4
| | - Ehud Haimov
- Department of Physiology and Pharmacology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 6997801, Israel.,Raymond and Beverly Sackler School of Physics and Astronomy, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Glenn F W Walpole
- Program in Cell Biology, Hospital for Sick Children, 686 Bay Street, Toronto, ON, Canada M5G 0A4.,Department of Biochemistry, University of Toronto, Toronto, ON, Canada M5S 1A8
| | - Jonathan Plumb
- Program in Cell Biology, Hospital for Sick Children, 686 Bay Street, Toronto, ON, Canada M5G 0A4
| | - Michael M Kozlov
- Department of Physiology and Pharmacology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Sergio Grinstein
- Program in Cell Biology, Hospital for Sick Children, 686 Bay Street, Toronto, ON, Canada M5G 0A4.,Department of Biochemistry, University of Toronto, Toronto, ON, Canada M5S 1A8.,Keenan Research Centre of the Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, ON, Canada M5C 1N8
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7
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Muzio MD, Millan-Solsona R, Borrell JH, Fumagalli L, Gomila G. Cholesterol Effect on the Specific Capacitance of Submicrometric DOPC Bilayer Patches Measured by in-Liquid Scanning Dielectric Microscopy. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:12963-12972. [PMID: 33084346 DOI: 10.1021/acs.langmuir.0c02251] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The specific capacitance of biological membranes is a key physical parameter in bioelectricity that also provides valuable physicochemical information on composition, phase, or hydration properties. Cholesterol is known to modulate the physicochemical properties of biomembranes, but its effect on the specific capacitance has not been fully established yet. Here we use the high spatial resolution capabilities of in-liquid scanning dielectric microscopy in force detection mode to directly demonstrate that DOPC bilayer patches at 50% cholesterol concentration show a strong reduction of their specific capacitance with respect to pure DOPC bilayer patches. The reduction observed (∼35%) cannot be explained by the small increase in bilayer thickness (∼16%). We suggest that the reduction of the specific capacitance might be due to the dehydration of the polar head groups caused by the insertion of cholesterol molecules in the bilayer. The results reported confirm the potential of in-liquid SDM to study the electrical and physicochemical properties of lipid bilayers at very small scales (down to ∼200 nm here), with implications in fields such as biophysics, bioelectricity, biochemistry, and biosensing.
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Affiliation(s)
- Martina Di Muzio
- Nanoscale Bioelectrical Characterization, Institut de Bioenginyeria de Catalunya, The Barcelona Institute of Science and Technology, 08028 Barcelona, Spain
| | - Ruben Millan-Solsona
- Nanoscale Bioelectrical Characterization, Institut de Bioenginyeria de Catalunya, The Barcelona Institute of Science and Technology, 08028 Barcelona, Spain
| | | | | | - Gabriel Gomila
- Nanoscale Bioelectrical Characterization, Institut de Bioenginyeria de Catalunya, The Barcelona Institute of Science and Technology, 08028 Barcelona, Spain
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8
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The Role of Membrane Surface Charge in Phagocytosis. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1246:43-54. [DOI: 10.1007/978-3-030-40406-2_3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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9
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Enforced expression of phosphatidylinositol 4-phosphate 5-kinase homolog alters PtdIns(4,5)P 2 distribution and the localization of small G-proteins. Sci Rep 2019; 9:14789. [PMID: 31616009 PMCID: PMC6794296 DOI: 10.1038/s41598-019-51272-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Accepted: 09/20/2019] [Indexed: 02/02/2023] Open
Abstract
The generation of phosphatidylinositol 4,5-bisphosphate (PtdIns(4,5)P2) by phosphatidylinositol 4-phosphate 5-kinases (PIP5Ks) is essential for many functions including control of the cytoskeleton, signal transduction, and endocytosis. Due to its presence in the plasma membrane and anionic charge, PtdIns(4,5)P2, together with phosphatidylserine, provide the inner leaflet of the plasma membrane with a negative surface charge. This negative charge helps to define the identity of the plasma membrane, as it serves to recruit or regulate a multitude of peripheral and membrane proteins that contain polybasic domains or patches. Here, we determine that the phosphatidylinositol 4-phosphate 5-kinase homolog (PIPKH) alters the subcellular distribution of PtdIns(4,5)P2 by re-localizing the three PIP5Ks to endomembranes. We find a redistribution of the PIP5K family members to endomembrane structures upon PIPKH overexpression that is accompanied by accumulation of PtdIns(4,5)P2 and phosphatidylinositol 3,4,5-trisphosphate (PtdIns(3,4,5)P3). PIP5Ks are targeted to membranes in part due to electrostatic interactions; however, the interaction between PIPKH and PIP5K is maintained following hydrolysis of PtdIns(4,5)P2. Expression of PIPKH did not impair bulk endocytosis as monitored by FM4-64 uptake but did result in clustering of FM4-64 positive endosomes. Finally, we demonstrate that accumulation of polyphosphoinositides increases the negative surface charge of endosomes and in turn, leads to relocalization of surface charge probes as well as the polycationic proteins K-Ras and Rac1.
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10
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Kay JG, Fairn GD. Distribution, dynamics and functional roles of phosphatidylserine within the cell. Cell Commun Signal 2019; 17:126. [PMID: 31615534 PMCID: PMC6792266 DOI: 10.1186/s12964-019-0438-z] [Citation(s) in RCA: 72] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Accepted: 09/10/2019] [Indexed: 12/19/2022] Open
Abstract
Phosphatidylserine (PtdSer), an essential constituent of eukaryotic membranes, is the most abundant anionic phospholipid in the eukaryotic cell accounting for up to 10% of the total cellular lipid. Much of what is known about PtdSer is the role exofacial PtdSer plays in apoptosis and blood clotting. However, PtdSer is generally not externally exposed in healthy cells and plays a vital role in several intracellular signaling pathways, though relatively little is known about the precise subcellular localization, transmembrane topology and intracellular dynamics of PtdSer within the cell. The recent development of new, genetically-encoded probes able to detect phosphatidylserine is leading to a more in-depth understanding of the biology of this phospholipid. This review aims to give an overview of recent developments in our understanding of the role of PtdSer in intracellular signaling events derived from the use of these recently developed methods of phosphatidylserine detection.
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Affiliation(s)
- Jason G Kay
- Department of Oral Biology, School of Dental Medicine, University at Buffalo, Buffalo, NY, 14214, USA.
| | - Gregory D Fairn
- Keenan Research Centre for Biomedical Science, St. Michael's Hospital, Toronto, ON, M5B 1W8, Canada. .,Department of Surgery, University of Toronto, Toronto, ON, M5S 1A8, Canada. .,Department of Biochemistry, University of Toronto, Toronto, ON, M5S 1A8, Canada.
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11
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Tuszynski J, Tilli TM, Levin M. Ion Channel and Neurotransmitter Modulators as Electroceutical Approaches to the Control of Cancer. Curr Pharm Des 2019; 23:4827-4841. [PMID: 28554310 PMCID: PMC6340161 DOI: 10.2174/1381612823666170530105837] [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: 04/13/2017] [Revised: 05/17/2017] [Accepted: 05/23/2017] [Indexed: 11/22/2022]
Abstract
The activities of individual cells must be tightly coordinated in order to build and maintain complex 3-dimensional body structures during embryogenesis and regeneration. Thus, one way to view cancer is within systems biology as a network disorder affecting the ability of cells to properly interact with a morphodynamic field of instructive signals that keeps proliferation and migration orchestrated toward the anatomical needs of the host or-ganism. One layer of this set of instructive microenvironmental cues is bioelectrical. Voltage gradients among all somatic cells (not just excitable nerve and muscle) control cell behavior, and the ionic coupling of cells into networks via electrochemical synapses allows them to implement tissue-level patterning decisions. These gradients have been increasingly impli-cated in the induction and suppression of tumorigenesis and metastasis, in the emerging links between developmental bioelectricity to the cancer problem. Consistent with the well-known role of neurotransmitter molecules in transducing electrical activity to downstream cascades in the brain, serotonergic signaling has likewise been implicated in cancer. Here, we review these recent data and propose new approaches for manipulating bioelectric and neurotransmitter pathways in cancer biology based on a bioelectric view of cancer. To sup-port this methodology, we present new data on the effects of the SSRI Prozac and its analog (ZINC ID = ZINC06811610) on survival of both cancer (MCF7) and normal (MCF10A) breast cells exposed to these compounds. We found an IC50 concentration (25 μM for Pro-zac and 100 μM for the Prozac analog) at which these compounds inhibited tumor cell sur-vival and proliferation. Additionally, at these concentrations, we did not observe alterations in a non-tumoral cell line. This constitutes a proof-of-concept demonstration for our hy-pothesis that the use of both existing and novel drugs as electroceuticals could serve as an alternative to highly toxic chemotherapy strategies replacing or augmenting them with less toxic alternatives. We believe this new approach forms an exciting roadmap for future bio-medical advances.
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Affiliation(s)
- Jack Tuszynski
- Department of Oncology, Faculty of Medicine & Dentistry, University of Alberta, Edmonton, Alberta. Canada
| | - Tatiana M Tilli
- Laboratory of Biological System Modeling, National Institute for Science and Technology on Innovation in Neglected Diseases (INCT/IDN), Center for Technological Development in Health (CDTS), Oswaldo Cruz Foundation (Fiocruz), Rio de Janeiro. Brazil
| | - Michael Levin
- Biology Department, and Allen Discovery Center, Tufts University, Medford, MA, 02155. United States
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Abstract
Modern stem cell research has mainly focused on protein expression and transcriptional networks. However, transmembrane voltage gradients generated by ion channels and transporters have demonstrated to be powerful regulators of cellular processes. These physiological cues exert influence on cell behaviors ranging from differentiation and proliferation to migration and polarity. Bioelectric signaling is a fundamental element of living systems and an untapped reservoir for new discoveries. Dissecting these mechanisms will allow for novel methods of controlling cell fate and open up new opportunities in biomedicine. This review focuses on the role of ion channels and the resting membrane potential in the proliferation and differentiation of skeletal muscle progenitor cells. In addition, findings relevant to this topic are presented and potential implications for tissue engineering and regenerative medicine are discussed.
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Affiliation(s)
- Colin Fennelly
- Department of Neuroscience, Novartis Institutes for BioMedical Research, Inc., Cambridge, Massachusetts
| | - Shay Soker
- Wake Forest Institute for Regenerative Medicine, Winston-Salem, North Carolina
- Wake Forest School of Medicine, Winston-Salem, North Carolina
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13
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Cauvi DM, Hawisher D, Dores-Silva PR, Lizardo RE, De Maio A. Macrophage reprogramming by negatively charged membrane phospholipids controls infection. FASEB J 2019; 33:2995-3009. [PMID: 30325674 PMCID: PMC6338646 DOI: 10.1096/fj.201801579r] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Accepted: 09/24/2018] [Indexed: 12/14/2022]
Abstract
Extracellular vesicles (ECVs) are heterogeneous membrane-enclosed structures containing proteins, nucleic acids, and lipids that participate in intercellular communication by transferring their contents to recipient cells. Although most of the attention has been directed at the biologic effect of proteins and microRNA, the contribution of phospholipids present in ECVs on cellular activation has not been extensively addressed. We investigated the biologic effect of phosphatidylserine (PS) and phosphatidylcholine (PC), 2 phospholipids highly abundant in ECVs. A transcriptomic analysis revealed that ∼4700 genes were specifically modified by exposing peritoneal macrophages to PS or PC liposomes in vivo. Among them, the expression of several chemokines and cytokines was highly upregulated by PS liposome treatment, translating into a massive neutrophil infiltration of the peritoneum capable of neutralizing a septic polymicrobial insult. Both the l and d stereoisomers of PS induced the same response, suggesting that the effect was related to the negative charge of the phospholipid head. We concluded that an increase in the internal negative charge of the cell triggers a signaling cascade activating an innate immune response capable of controlling infection.-Cauvi, D. M., Hawisher, D., Dores-Silva, P. R., Lizardo, R. E., De Maio, A. Macrophage reprogramming by negatively charged membrane phospholipids controls infection.
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Affiliation(s)
- David M. Cauvi
- Department of Surgery, School of Medicine, University of California San Diego, La Jolla, California, USA; and
| | - Dennis Hawisher
- Department of Surgery, School of Medicine, University of California San Diego, La Jolla, California, USA; and
| | - Paulo R. Dores-Silva
- Department of Surgery, School of Medicine, University of California San Diego, La Jolla, California, USA; and
| | - Radhames E. Lizardo
- Department of Surgery, Naval Medical Center San Diego, San Diego, California, USA
| | - Antonio De Maio
- Department of Surgery, School of Medicine, University of California San Diego, La Jolla, California, USA; and
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14
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Baluška F, Miller, Jr WB. Senomic view of the cell: Senome versus Genome. Commun Integr Biol 2018; 11:1-9. [PMID: 30214674 PMCID: PMC6132427 DOI: 10.1080/19420889.2018.1489184] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Accepted: 06/11/2018] [Indexed: 12/25/2022] Open
Abstract
In the legacy of Thomas Henry Huxley, and his 'epigenetic' philosophy of biology, cells are proposed to represent a trinity of three memory-storing media: Senome, Epigenome, and Genome that together comprise a cell-wide informational architecture. Our current preferential focus on the Genome needs to be complemented by a similar focus on the Epigenome and a here proposed Senome, representing the sum of all the sensory experiences of the cognitive cell and its sensing apparatus. Only then will biology be in a position to embrace the whole complexity of the eukaryotic cell, understanding its true nature which allows the communicative assembly of cells in the form of sentient multicellular organisms.
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15
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Infectious Bursal Disease Virus Hijacks Endosomal Membranes as the Scaffolding Structure for Viral Replication. J Virol 2018. [PMID: 29540593 DOI: 10.1128/jvi.01964-17] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Birnaviruses are unconventional members of the group of double-stranded RNA (dsRNA) viruses that are characterized by the lack of a transcriptionally active inner core. Instead, the birnaviral particles organize their genome in ribonucleoprotein complexes (RNPs) composed by dsRNA segments, the dsRNA-binding VP3 protein, and the virally encoded RNA-dependent RNA polymerase (RdRp). This and other structural features suggest that birnaviruses may follow a completely different replication program from that followed by members of the Reoviridae family, supporting the hypothesis that birnaviruses are the evolutionary link between single-stranded positive RNA (+ssRNA) and dsRNA viruses. Here we demonstrate that infectious bursal disease virus (IBDV), a prototypical member of the Birnaviridae family, hijacks endosomal membranes of infected cells through the interaction of a viral protein, VP3, with the phospholipids on the cytosolic leaflet of these compartments for replication. Employing a mutagenesis approach, we demonstrated that VP3 domain PATCH 2 (P2) mediates the association of VP3 with the endosomal membranes. To determine the role of VP3 P2 in the context of the virus replication cycle, we used avian cells stably overexpressing VP3 P2 for IBDV infection. Importantly, the intra- and extracellular virus yields, as well as the intracellular levels of VP2 viral capsid protein, were significantly diminished in cells stably overexpressing VP3 P2. Together, our results indicate that the association of VP3 with endosomes has a relevant role in the IBDV replication cycle. This report provides direct experimental evidence for membranous compartments such as endosomes being required by a dsRNA virus for its replication. The results also support the previously proposed role of birnaviruses as an evolutionary link between +ssRNA and dsRNA viruses.IMPORTANCE Infectious bursal disease (IBD; also called Gumboro disease) is an acute, highly contagious immunosuppressive disease that affects young chickens and spreads worldwide. The etiological agent of IBD is infectious bursal disease virus (IBDV). This virus destroys the central immune organ (bursa of Fabricius), resulting in immunosuppression and reduced responses of chickens to vaccines, which increase their susceptibility to other pathogens. IBDV is a member of Birnaviridae family, which comprises unconventional members of dsRNA viruses, whose replication strategy has been scarcely studied. In this report we show that IBDV hijacks the endosomes of the infected cells for establishing viral replication complexes via the association of the ribonucleoprotein complex component VP3 with the phospholipids in the cytosolic leaflet of endosomal membranes. We show that this interaction is mediated by the VP3 PATCH 2 domain and demonstrate its relevant role in the context of viral infection.
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16
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McLaughlin KA, Levin M. Bioelectric signaling in regeneration: Mechanisms of ionic controls of growth and form. Dev Biol 2018; 433:177-189. [PMID: 29291972 PMCID: PMC5753428 DOI: 10.1016/j.ydbio.2017.08.032] [Citation(s) in RCA: 132] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Revised: 08/23/2017] [Accepted: 08/28/2017] [Indexed: 12/11/2022]
Abstract
The ability to control pattern formation is critical for the both the embryonic development of complex structures as well as for the regeneration/repair of damaged or missing tissues and organs. In addition to chemical gradients and gene regulatory networks, endogenous ion flows are key regulators of cell behavior. Not only do bioelectric cues provide information needed for the initial development of structures, they also enable the robust restoration of normal pattern after injury. In order to expand our basic understanding of morphogenetic processes responsible for the repair of complex anatomy, we need to identify the roles of endogenous voltage gradients, ion flows, and electric fields. In complement to the current focus on molecular genetics, decoding the information transduced by bioelectric cues enhances our knowledge of the dynamic control of growth and pattern formation. Recent advances in science and technology place us in an exciting time to elucidate the interplay between molecular-genetic inputs and important biophysical cues that direct the creation of tissues and organs. Moving forward, these new insights enable additional approaches to direct cell behavior and may result in profound advances in augmentation of regenerative capacity.
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Affiliation(s)
- Kelly A McLaughlin
- Allen Discovery Center, Department of Biology, Tufts University, 200 Boston Ave., Suite 4700, Medford, MA 02155, United States.
| | - Michael Levin
- Allen Discovery Center, Department of Biology, Tufts University, 200 Boston Ave., Suite 4700, Medford, MA 02155, United States
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17
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Michaeli L, Gottfried I, Bykhovskaia M, Ashery U. Phosphatidylinositol (4, 5)-bisphosphate targets double C2 domain protein B to the plasma membrane. Traffic 2017; 18:825-839. [PMID: 28941037 DOI: 10.1111/tra.12528] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Revised: 09/18/2017] [Accepted: 09/18/2017] [Indexed: 01/05/2023]
Abstract
Double C2 domain protein B (DOC2B) is a high-affinity Ca2+ sensor that translocates from the cytosol to the plasma membrane (PM) and promotes vesicle priming and fusion. However, the molecular mechanism underlying its translocation and targeting to the PM in living cells is not completely understood. DOC2B interacts in vitro with the PM components phosphatidylserine, phosphatidylinositol (4, 5)-bisphosphate [PI(4, 5)P2 ] and target SNAREs (t-SNAREs). Here, we show that PI(4, 5)P2 hydrolysis at the PM of living cells abolishes DOC2B translocation, whereas manipulations of t-SNAREs and other phosphoinositides have no effect. Moreover, we were able to redirect DOC2B to intracellular membranes by synthesizing PI(4, 5)P2 in those membranes. Molecular dynamics simulations and mutagenesis in the calcium and PI(4, 5)P2 -binding sites strengthened our findings, demonstrating that both calcium and PI(4, 5)P2 are required for the DOC2B-PM association and revealing multiple PI(4, 5)P2 -C2B interactions. In addition, we show that DOC2B translocation to the PM is ATP-independent and occurs in a diffusion-like manner. Our data suggest that the Ca2+ -triggered translocation of DOC2B is diffusion-driven and aimed at PI(4, 5)P2 -containing membranes.
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Affiliation(s)
- Lirin Michaeli
- Department of Neurobiology, Faculty of Life Sciences, Tel-Aviv University, Tel Aviv, Israel
| | - Irit Gottfried
- Department of Neurobiology, Faculty of Life Sciences, Tel-Aviv University, Tel Aviv, Israel
| | | | - Uri Ashery
- Department of Neurobiology, Faculty of Life Sciences, Tel-Aviv University, Tel Aviv, Israel.,Sagol School of Neuroscience, Tel-Aviv University, Tel Aviv, Israel
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18
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Ye H. Kinematic difference between a biological cell and an artificial vesicle in a strong DC electric field – a “shell” membrane model study. BMC BIOPHYSICS 2017. [DOI: 10.1186/s13628-017-0038-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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19
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Levin M, Pezzulo G, Finkelstein JM. Endogenous Bioelectric Signaling Networks: Exploiting Voltage Gradients for Control of Growth and Form. Annu Rev Biomed Eng 2017; 19:353-387. [PMID: 28633567 PMCID: PMC10478168 DOI: 10.1146/annurev-bioeng-071114-040647] [Citation(s) in RCA: 142] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Living systems exhibit remarkable abilities to self-assemble, regenerate, and remodel complex shapes. How cellular networks construct and repair specific anatomical outcomes is an open question at the heart of the next-generation science of bioengineering. Developmental bioelectricity is an exciting emerging discipline that exploits endogenous bioelectric signaling among many cell types to regulate pattern formation. We provide a brief overview of this field, review recent data in which bioelectricity is used to control patterning in a range of model systems, and describe the molecular tools being used to probe the role of bioelectrics in the dynamic control of complex anatomy. We suggest that quantitative strategies recently developed to infer semantic content and information processing from ionic activity in the brain might provide important clues to cracking the bioelectric code. Gaining control of the mechanisms by which large-scale shape is regulated in vivo will drive transformative advances in bioengineering, regenerative medicine, and synthetic morphology, and could be used to therapeutically address birth defects, traumatic injury, and cancer.
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Affiliation(s)
- Michael Levin
- Biology Department, Tufts University, Medford, Massachusetts 02155-4243;
- Allen Discovery Center, Tufts University, Medford, Massachusetts 02155;
| | - Giovanni Pezzulo
- Institute of Cognitive Sciences and Technologies, National Research Council, Rome 00185, Italy;
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20
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Haupt A, Minc N. Gradients of phosphatidylserine contribute to plasma membrane charge localization and cell polarity in fission yeast. Mol Biol Cell 2016; 28:210-220. [PMID: 27852900 PMCID: PMC5221626 DOI: 10.1091/mbc.e16-06-0353] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Revised: 11/07/2016] [Accepted: 11/08/2016] [Indexed: 12/19/2022] Open
Abstract
Surface charges at the inner leaflet of the plasma membrane may contribute to regulate the surface recruitment of key signaling factors. Phosphatidylserine (PS) is an abundant charged lipid that may regulate charge distribution in different cell types. Here we characterize the subcellular distribution and function of PS in the rod-shaped, polarized fission yeast. We find that PS preferably accumulates at cell tips and defines a gradient of negative charges along the cell surface. This polarization depends on actin-mediated endocytosis and contributes to the subcellular partitioning of charged polarity-regulating Rho GTPases like Rho1 or Cdc42 in a protein charge-dependent manner. Cells depleted of PS have altered cell dimensions and fail to properly regulate growth from the second end, suggesting a role for PS and membrane charge in polarized cell growth.
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Affiliation(s)
- Armin Haupt
- Institut Jacques Monod, 75205 Paris Cedex 13, France
| | - Nicolas Minc
- Institut Jacques Monod, 75205 Paris Cedex 13, France
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21
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Ross CL. The use of electric, magnetic, and electromagnetic field for directed cell migration and adhesion in regenerative medicine. Biotechnol Prog 2016; 33:5-16. [PMID: 27797153 DOI: 10.1002/btpr.2371] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Revised: 10/10/2016] [Indexed: 01/01/2023]
Abstract
Directed cell migration and adhesion is essential to embryonic development, tissue formation and wound healing. For decades it has been reported that electric field (EF), magnetic field (MF) and electromagnetic field (EMF) can play important roles in determining cell differentiation, migration, adhesion, and evenwound healing. Combinations of these techniques have revealed new and exciting explanations for how cells move and adhere to surfaces; how the migration of multiple cells are coordinated and regulated; how cellsinteract with neighboring cells, and also to changes in their microenvironment. In some cells, speed and direction are voltage dependent. Data suggests that the use of EF, MF and EMF could advance techniques in regenerative medicine, tissue engineering and wound healing. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 33:5-16, 2017.
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Affiliation(s)
- Christina L Ross
- The Wake Forest Institute for Regenerative Medicine, Wake Forest Center for Integrative Medicine, Medical Center Blvd, Winston-Salem, NC
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22
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Sustained Depolarization of the Resting Membrane Potential Regulates Muscle Progenitor Cell Growth and Maintains Stem Cell Properties In Vitro. Stem Cell Rev Rep 2016; 12:634-644. [DOI: 10.1007/s12015-016-9687-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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23
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The Epithelial Sodium Channel and the Processes of Wound Healing. BIOMED RESEARCH INTERNATIONAL 2016; 2016:5675047. [PMID: 27493961 PMCID: PMC4963570 DOI: 10.1155/2016/5675047] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Accepted: 06/15/2016] [Indexed: 12/19/2022]
Abstract
The epithelial sodium channel (ENaC) mediates passive sodium transport across the apical membranes of sodium absorbing epithelia, like the distal nephron, the intestine, and the lung airways. Additionally, the channel has been involved in the transduction of mechanical stimuli, such as hydrostatic pressure, membrane stretch, and shear stress from fluid flow. Thus, in vascular endothelium, it participates in the control of the vascular tone via its activity both as a sodium channel and as a shear stress transducer. Rather recently, ENaC has been shown to participate in the processes of wound healing, a role that may also involve its activities as sodium transporter and as mechanotransducer. Its presence as the sole channel mediating sodium transport in many tissues and the diversity of its functions probably underlie the complexity of its regulation. This brief review describes some aspects of ENaC regulation, comments on evidence about ENaC participation in wound healing, and suggests possible regulatory mechanisms involved in this participation.
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24
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Scholkmann F. Long range physical cell-to-cell signalling via mitochondria inside membrane nanotubes: a hypothesis. Theor Biol Med Model 2016; 13:16. [PMID: 27267202 PMCID: PMC4896004 DOI: 10.1186/s12976-016-0042-5] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Accepted: 05/27/2016] [Indexed: 02/07/2023] Open
Abstract
Coordinated interaction of single cells by cell-to-cell communication (signalling) enables complex behaviour necessary for the functioning of multicellular organisms. A quite newly discovered cell-to-cell signalling mechanism relies on nanotubular cell-co-cell connections, termed "membrane nanotubes" (MNTs). The present paper presents the hypothesis that mitochondria inside MNTs can form a connected structure (mitochondrial network) which enables the exchange of energy and signals between cells. It is proposed that two modes of energy and signal transmission may occur: electrical/electrochemical and electromagnetic (optical). Experimental work supporting the hypothesis is reviewed, and suggestions for future research regarding the discussed topic are given.
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Affiliation(s)
- Felix Scholkmann
- Biomedical Optics Research Laboratory, Department of Neonatology, University Hospital Zurich, University of Zurich, Frauenklinikstr. 10, 8091, Zurich, Switzerland.
- Research Office for Complex Physical and Biological Systems (ROCoS), Mutschellenstr. 179, 8038, Zurich, Switzerland.
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25
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Biomechanics of cell membrane under low-frequency time-varying magnetic field: a shell model. Med Biol Eng Comput 2016; 54:1871-1881. [DOI: 10.1007/s11517-016-1478-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Accepted: 02/25/2016] [Indexed: 11/27/2022]
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26
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Shi Y, Acerson MJ, Shuford KL, Shaw BF. Voltage-Induced Misfolding of Zinc-Replete ALS Mutant Superoxide Dismutase-1. ACS Chem Neurosci 2015. [PMID: 26207449 DOI: 10.1021/acschemneuro.5b00146] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The monomerization of Cu, Zn superoxide dismutase (SOD1) is an early step along pathways of misfolding linked to amyotrophic lateral sclerosis (ALS). Monomerization requires the reversal of two post-translational modifications that are thermodynamically favorable: (i) dissociation of active-site metal ions and (ii) reduction of intramolecular disulfide bonds. This study found, using amide hydrogen/deuterium (H/D) exchange, capillary electrophoresis, and lysine-acetyl protein charge ladders, that ALS-linked A4V SOD1 rapidly monomerizes and partially unfolds in an external electric field (of physiological strength), without loss of metal ions, exposure to disulfide-reducing agents, or Joule heating. Voltage-induced monomerization was not observed for metal-free A4V SOD1, metal-free WT SOD1, or metal-loaded WT SOD1. Computational modeling suggested a mechanism for this counterintuitive effect: subunit macrodipoles of dimeric SOD1 are antiparallel and amplified 2-fold by metal coordination, which increases torque at the dimer interface as subunits rotate to align with the electric field.
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Affiliation(s)
- Yunhua Shi
- Department
of Chemistry and
Biochemistry, Baylor University, Waco, Texas 76706, United States
| | - Mark J. Acerson
- Department
of Chemistry and
Biochemistry, Baylor University, Waco, Texas 76706, United States
| | - Kevin L. Shuford
- Department
of Chemistry and
Biochemistry, Baylor University, Waco, Texas 76706, United States
| | - Bryan F. Shaw
- Department
of Chemistry and
Biochemistry, Baylor University, Waco, Texas 76706, United States
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27
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Levin M. Molecular bioelectricity: how endogenous voltage potentials control cell behavior and instruct pattern regulation in vivo. Mol Biol Cell 2015; 25:3835-50. [PMID: 25425556 PMCID: PMC4244194 DOI: 10.1091/mbc.e13-12-0708] [Citation(s) in RCA: 221] [Impact Index Per Article: 24.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
In addition to biochemical gradients and transcriptional networks, cell behavior is regulated by endogenous bioelectrical cues originating in the activity of ion channels and pumps, operating in a wide variety of cell types. Instructive signals mediated by changes in resting potential control proliferation, differentiation, cell shape, and apoptosis of stem, progenitor, and somatic cells. Of importance, however, cells are regulated not only by their own Vmem but also by the Vmem of their neighbors, forming networks via electrical synapses known as gap junctions. Spatiotemporal changes in Vmem distribution among nonneural somatic tissues regulate pattern formation and serve as signals that trigger limb regeneration, induce eye formation, set polarity of whole-body anatomical axes, and orchestrate craniofacial patterning. New tools for tracking and functionally altering Vmem gradients in vivo have identified novel roles for bioelectrical signaling and revealed the molecular pathways by which Vmem changes are transduced into cascades of downstream gene expression. Because channels and gap junctions are gated posttranslationally, bioelectrical networks have their own characteristic dynamics that do not reduce to molecular profiling of channel expression (although they couple functionally to transcriptional networks). The recent data provide an exciting opportunity to crack the bioelectric code, and learn to program cellular activity at the level of organs, not only cell types. The understanding of how patterning information is encoded in bioelectrical networks, which may require concepts from computational neuroscience, will have transformative implications for embryogenesis, regeneration, cancer, and synthetic bioengineering.
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Affiliation(s)
- Michael Levin
- Biology Department, Center for Regenerative and Developmental Biology, Tufts University, Medford, MA 02155-4243
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28
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Host Cell Plasma Membrane Phosphatidylserine Regulates the Assembly and Budding of Ebola Virus. J Virol 2015; 89:9440-53. [PMID: 26136573 DOI: 10.1128/jvi.01087-15] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2015] [Accepted: 06/29/2015] [Indexed: 01/25/2023] Open
Abstract
UNLABELLED Lipid-enveloped viruses replicate and bud from the host cell where they acquire their lipid coat. Ebola virus, which buds from the plasma membrane of the host cell, causes viral hemorrhagic fever and has a high fatality rate. To date, little has been known about how budding and egress of Ebola virus are mediated at the plasma membrane. We have found that the lipid phosphatidylserine (PS) regulates the assembly of Ebola virus matrix protein VP40. VP40 binds PS-containing membranes with nanomolar affinity, and binding of PS regulates VP40 localization and oligomerization on the plasma membrane inner leaflet. Further, alteration of PS levels in mammalian cells inhibits assembly and egress of VP40. Notably, interactions of VP40 with the plasma membrane induced exposure of PS on the outer leaflet of the plasma membrane at sites of egress, whereas PS is typically found only on the inner leaflet. Taking the data together, we present a model accounting for the role of plasma membrane PS in assembly of Ebola virus-like particles. IMPORTANCE The lipid-enveloped Ebola virus causes severe infection with a high mortality rate and currently lacks FDA-approved therapeutics or vaccines. Ebola virus harbors just seven genes in its genome, and there is a critical requirement for acquisition of its lipid envelope from the plasma membrane of the human cell that it infects during the replication process. There is, however, a dearth of information available on the required contents of this envelope for egress and subsequent attachment and entry. Here we demonstrate that plasma membrane phosphatidylserine is critical for Ebola virus budding from the host cell plasma membrane. This report, to our knowledge, is the first to highlight the role of lipids in human cell membranes in the Ebola virus replication cycle and draws a clear link between selective binding and transport of a lipid across the membrane of the human cell and use of that lipid for subsequent viral entry.
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29
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Ye H, Curcuru A. Vesicle biomechanics in a time-varying magnetic field. BMC BIOPHYSICS 2015; 8:2. [PMID: 25649322 PMCID: PMC4306248 DOI: 10.1186/s13628-014-0016-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Accepted: 12/08/2014] [Indexed: 11/29/2022]
Abstract
Background Cells exhibit distortion when exposed to a strong electric field, suggesting that the field imposes control over cellular biomechanics. Closed pure lipid bilayer membranes (vesicles) have been widely used for the experimental and theoretical studies of cellular biomechanics under this electrodeformation. An alternative method used to generate an electric field is by electromagnetic induction with a time-varying magnetic field. References reporting the magnetic control of cellular mechanics have recently emerged. However, theoretical analysis of the cellular mechanics under a time-varying magnetic field is inadequate. We developed an analytical theory to investigate the biomechanics of a modeled vesicle under a time-varying magnetic field. Following previous publications and to simplify the calculation, this model treated the inner and suspending media as lossy dielectrics, the membrane thickness set at zero, and the electric resistance of the membrane assumed to be negligible. This work provided the first analytical solutions for the surface charges, electric field, radial pressure, overall translational forces, and rotational torques introduced on a vesicle by the time-varying magnetic field. Frequency responses of these measures were analyzed, particularly the frequency used clinically by transcranial magnetic stimulation (TMS). Results The induced surface charges interacted with the electric field to produce a biomechanical impact upon the vesicle. The distribution of the induced surface charges depended on the orientation of the coil and field frequency. The densities of these charges were trivial at low frequency ranges, but significant at high frequency ranges. The direction of the radial force on the vesicle was dependent on the conductivity ratio between the vesicle and the medium. At relatively low frequencies (<200 KHz), including the frequency used in TMS, the computed radial pressure and translational forces on the vesicle were both negligible. Conclusions This work provides an analytical framework and insight into factors affecting cellular biomechanics under a time-varying magnetic field. Biological effects of clinical TMS are not likely to occur via alteration of the biomechanics of brain cells.
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Affiliation(s)
- Hui Ye
- Department of Biology, Loyola University Chicago, 1032 W. Sheridan Rd, Chicago, IL 60660 USA
| | - Austen Curcuru
- Departments of Physics, Loyola University Chicago, 1032 W. Sheridan Rd, Chicago, IL 60660 USA
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30
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Levin M. Endogenous bioelectrical networks store non-genetic patterning information during development and regeneration. J Physiol 2015; 592:2295-305. [PMID: 24882814 DOI: 10.1113/jphysiol.2014.271940] [Citation(s) in RCA: 137] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Pattern formation, as occurs during embryogenesis or regeneration, is the crucial link between genotype and the functions upon which selection operates. Even cancer and aging can be seen as challenges to the continuous physiological processes that orchestrate individual cell activities toward the anatomical needs of an organism. Thus, the origin and maintenance of complex biological shape is a fundamental question for cell, developmental, and evolutionary biology, as well as for biomedicine. It has long been recognized that slow bioelectrical gradients can control cell behaviors and morphogenesis. Here, I review recent molecular data that implicate endogenous spatio-temporal patterns of resting potentials among non-excitable cells as instructive cues in embryogenesis, regeneration, and cancer. Functional data have implicated gradients of resting potential in processes such as limb regeneration, eye induction, craniofacial patterning, and head-tail polarity, as well as in metastatic transformation and tumorigenesis. The genome is tightly linked to bioelectric signaling, via ion channel proteins that shape the gradients, downstream genes whose transcription is regulated by voltage, and transduction machinery that converts changes in bioelectric state to second-messenger cascades. However, the data clearly indicate that bioelectric signaling is an autonomous layer of control not reducible to a biochemical or genetic account of cell state. The real-time dynamics of bioelectric communication among cells are not fully captured by transcriptomic or proteomic analyses, and the necessary-and-sufficient triggers for specific changes in growth and form can be physiological states, while the underlying gene loci are free to diverge. The next steps in this exciting new field include the development of novel conceptual tools for understanding the anatomical semantics encoded in non-neural bioelectrical networks, and of improved biophysical tools for reading and writing electrical state information into somatic tissues. Cracking the bioelectric code will have transformative implications for developmental biology, regenerative medicine, and synthetic bioengineering.
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Affiliation(s)
- Michael Levin
- Biology Department, Center for Regenerative and Developmental Biology, Tufts University, Medford, MA, USA
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31
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Huston RL. Using the Electromagnetics of Cancer’s Centrosome Clusters to Attract Therapeutic Nanoparticles. ACTA ACUST UNITED AC 2015. [DOI: 10.4236/abb.2015.63017] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Khitrin A, Khitrin K, Model M. A model for membrane potential and intracellular ion distribution. Chem Phys Lipids 2014; 184:76-81. [DOI: 10.1016/j.chemphyslip.2014.10.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2014] [Revised: 10/27/2014] [Accepted: 10/31/2014] [Indexed: 10/24/2022]
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Mustard J, Levin M. Bioelectrical Mechanisms for Programming Growth and Form: Taming Physiological Networks for Soft Body Robotics. Soft Robot 2014. [DOI: 10.1089/soro.2014.0011] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Affiliation(s)
- Jessica Mustard
- Department of Biology and Center for Regenerative and Developmental Biology, Tufts University, Medford, Massachusetts
| | - Michael Levin
- Department of Biology and Center for Regenerative and Developmental Biology, Tufts University, Medford, Massachusetts
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Theillet FX, Binolfi A, Frembgen-Kesner T, Hingorani K, Sarkar M, Kyne C, Li C, Crowley PB, Gierasch L, Pielak GJ, Elcock AH, Gershenson A, Selenko P. Physicochemical properties of cells and their effects on intrinsically disordered proteins (IDPs). Chem Rev 2014; 114:6661-714. [PMID: 24901537 PMCID: PMC4095937 DOI: 10.1021/cr400695p] [Citation(s) in RCA: 338] [Impact Index Per Article: 33.8] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2013] [Indexed: 02/07/2023]
Affiliation(s)
- Francois-Xavier Theillet
- Department
of NMR-supported Structural Biology, In-cell NMR Laboratory, Leibniz Institute of Molecular Pharmacology (FMP Berlin), Robert-Roessle Strasse 10, 13125 Berlin, Germany
| | - Andres Binolfi
- Department
of NMR-supported Structural Biology, In-cell NMR Laboratory, Leibniz Institute of Molecular Pharmacology (FMP Berlin), Robert-Roessle Strasse 10, 13125 Berlin, Germany
| | - Tamara Frembgen-Kesner
- Department
of Biochemistry, University of Iowa, Bowen Science Building, 51 Newton
Road, Iowa City, Iowa 52242, United States
| | - Karan Hingorani
- Departments
of Biochemistry & Molecular Biology and Chemistry, Program in
Molecular & Cellular Biology, University
of Massachusetts, Amherst, 240 Thatcher Way, Amherst, Massachusetts 01003, United States
| | - Mohona Sarkar
- Department
of Chemistry, Department of Biochemistry and Biophysics and Lineberger
Comprehensive Cancer Center, University
of North Carolina, Chapel Hill, Chapel Hill, North Carolina 27599-3290, United States
| | - Ciara Kyne
- School
of Chemistry, National University of Ireland,
Galway, University Road, Galway, Ireland
| | - Conggang Li
- Key Laboratory
of Magnetic Resonance in Biological Systems, State Key Laboratory
of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Center
for Magnetic Resonance, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan, 430071, P.R. China
| | - Peter B. Crowley
- School
of Chemistry, National University of Ireland,
Galway, University Road, Galway, Ireland
| | - Lila Gierasch
- Departments
of Biochemistry & Molecular Biology and Chemistry, Program in
Molecular & Cellular Biology, University
of Massachusetts, Amherst, 240 Thatcher Way, Amherst, Massachusetts 01003, United States
| | - Gary J. Pielak
- Department
of Chemistry, Department of Biochemistry and Biophysics and Lineberger
Comprehensive Cancer Center, University
of North Carolina, Chapel Hill, Chapel Hill, North Carolina 27599-3290, United States
| | - Adrian H. Elcock
- Department
of Biochemistry, University of Iowa, Bowen Science Building, 51 Newton
Road, Iowa City, Iowa 52242, United States
| | - Anne Gershenson
- Departments
of Biochemistry & Molecular Biology and Chemistry, Program in
Molecular & Cellular Biology, University
of Massachusetts, Amherst, 240 Thatcher Way, Amherst, Massachusetts 01003, United States
| | - Philipp Selenko
- Department
of NMR-supported Structural Biology, In-cell NMR Laboratory, Leibniz Institute of Molecular Pharmacology (FMP Berlin), Robert-Roessle Strasse 10, 13125 Berlin, Germany
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Stahelin RV, Scott JL, Frick CT. Cellular and molecular interactions of phosphoinositides and peripheral proteins. Chem Phys Lipids 2014; 182:3-18. [PMID: 24556335 DOI: 10.1016/j.chemphyslip.2014.02.002] [Citation(s) in RCA: 82] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2014] [Revised: 02/05/2014] [Accepted: 02/05/2014] [Indexed: 12/23/2022]
Abstract
Anionic lipids act as signals for the recruitment of proteins containing cationic clusters to biological membranes. A family of anionic lipids known as the phosphoinositides (PIPs) are low in abundance, yet play a critical role in recruitment of peripheral proteins to the membrane interface. PIPs are mono-, bis-, or trisphosphorylated derivatives of phosphatidylinositol (PI) yielding seven species with different structure and anionic charge. The differential spatial distribution and temporal appearance of PIPs is key to their role in communicating information to target proteins. Selective recognition of PIPs came into play with the discovery that the substrate of protein kinase C termed pleckstrin possessed the first PIP binding region termed the pleckstrin homology (PH) domain. Since the discovery of the PH domain, more than ten PIP binding domains have been identified including PH, ENTH, FYVE, PX, and C2 domains. Representative examples of each of these domains have been thoroughly characterized to understand how they coordinate PIP headgroups in membranes, translocate to specific membrane docking sites in the cell, and function to regulate the activity of their full-length proteins. In addition, a number of novel mechanisms of PIP-mediated membrane association have emerged, such as coincidence detection-specificity for two distinct lipid headgroups. Other PIP-binding domains may also harbor selectivity for a membrane physical property such as charge or membrane curvature. This review summarizes the current understanding of the cellular distribution of PIPs and their molecular interaction with peripheral proteins.
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Affiliation(s)
- Robert V Stahelin
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine-South Bend, South Bend, IN 46617, United States; Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556, United States; Mike and Josie Harper Cancer Research Institute, University of Notre Dame, Notre Dame, IN 46556, United States.
| | - Jordan L Scott
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556, United States; Mike and Josie Harper Cancer Research Institute, University of Notre Dame, Notre Dame, IN 46556, United States
| | - Cary T Frick
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556, United States
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Alfsen A, Tatischeff I. The Lipid Bilayer of Biological Vesicles: A Liquid-Crystalline Material as Nanovehicles of Information. ACTA ACUST UNITED AC 2014. [DOI: 10.4236/jbnb.2014.52013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Stock C, Ludwig FT, Hanley PJ, Schwab A. Roles of ion transport in control of cell motility. Compr Physiol 2013; 3:59-119. [PMID: 23720281 DOI: 10.1002/cphy.c110056] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Cell motility is an essential feature of life. It is essential for reproduction, propagation, embryonic development, and healing processes such as wound closure and a successful immune defense. If out of control, cell motility can become life-threatening as, for example, in metastasis or autoimmune diseases. Regardless of whether ciliary/flagellar or amoeboid movement, controlled motility always requires a concerted action of ion channels and transporters, cytoskeletal elements, and signaling cascades. Ion transport across the plasma membrane contributes to cell motility by affecting the membrane potential and voltage-sensitive ion channels, by inducing local volume changes with the help of aquaporins and by modulating cytosolic Ca(2+) and H(+) concentrations. Voltage-sensitive ion channels serve as voltage detectors in electric fields thus enabling galvanotaxis; local swelling facilitates the outgrowth of protrusions at the leading edge while local shrinkage accompanies the retraction of the cell rear; the cytosolic Ca(2+) concentration exerts its main effect on cytoskeletal dynamics via motor proteins such as myosin or dynein; and both, the intracellular and the extracellular H(+) concentration modulate cell migration and adhesion by tuning the activity of enzymes and signaling molecules in the cytosol as well as the activation state of adhesion molecules at the cell surface. In addition to the actual process of ion transport, both, channels and transporters contribute to cell migration by being part of focal adhesion complexes and/or physically interacting with components of the cytoskeleton. The present article provides an overview of how the numerous ion-transport mechanisms contribute to the various modes of cell motility.
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Affiliation(s)
- Christian Stock
- Institute of Physiology II, University of Münster, Münster, Germany.
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Andreev VP. Cytoplasmic electric fields and electroosmosis: possible solution for the paradoxes of the intracellular transport of biomolecules. PLoS One 2013; 8:e61884. [PMID: 23613967 PMCID: PMC3627925 DOI: 10.1371/journal.pone.0061884] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2012] [Accepted: 03/16/2013] [Indexed: 12/02/2022] Open
Abstract
The objective of the paper is to show that electroosmotic flow might play an important role in the intracellular transport of biomolecules. The paper presents two mathematical models describing the role of electroosmosis in the transport of the negatively charged messenger proteins to the negatively charged nucleus and in the recovery of the fluorescence after photobleaching. The parameters of the models were derived from the extensive review of the literature data. Computer simulations were performed within the COMSOL 4.2a software environment. The first model demonstrated that the presence of electroosmosis might intensify the flux of messenger proteins to the nucleus and allow the efficient transport of the negatively charged phosphorylated messenger proteins against the electrostatic repulsion of the negatively charged nucleus. The second model revealed that the presence of the electroosmotic flow made the time of fluorescence recovery dependent on the position of the bleaching spot relative to cellular membrane. The magnitude of the electroosmotic flow effect was shown to be quite substantial, i.e. increasing the flux of the messengers onto the nucleus up to 4-fold relative to pure diffusion and resulting in the up to 3-fold change in the values of fluorescence recovery time, and therefore the apparent diffusion coefficient determined from the fluorescence recovery after photobleaching experiments. Based on the results of the modeling and on the universal nature of the electroosmotic flow, the potential wider implications of electroosmotic flow in the intracellular and extracellular biological processes are discussed. Both models are available for download at ModelDB.
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Affiliation(s)
- Victor P Andreev
- Department of Psychiatry and Behavioral Sciences, University of Miami Miller School of Medicine, Miami, Florida, United States of America.
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Adams DS, Levin M. Endogenous voltage gradients as mediators of cell-cell communication: strategies for investigating bioelectrical signals during pattern formation. Cell Tissue Res 2013; 352:95-122. [PMID: 22350846 PMCID: PMC3869965 DOI: 10.1007/s00441-012-1329-4] [Citation(s) in RCA: 116] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2011] [Accepted: 01/12/2012] [Indexed: 01/07/2023]
Abstract
Alongside the well-known chemical modes of cell-cell communication, we find an important and powerful system of bioelectrical signaling: changes in the resting voltage potential (Vmem) of the plasma membrane driven by ion channels, pumps and gap junctions. Slow Vmem changes in all cells serve as a highly conserved, information-bearing pathway that regulates cell proliferation, migration and differentiation. In embryonic and regenerative pattern formation and in the disorganization of neoplasia, bioelectrical cues serve as mediators of large-scale anatomical polarity, organ identity and positional information. Recent developments have resulted in tools that enable a high-resolution analysis of these biophysical signals and their linkage with upstream and downstream canonical genetic pathways. Here, we provide an overview for the study of bioelectric signaling, focusing on state-of-the-art approaches that use molecular physiology and developmental genetics to probe the roles of bioelectric events functionally. We highlight the logic, strategies and well-developed technologies that any group of researchers can employ to identify and dissect ionic signaling components in their own work and thus to help crack the bioelectric code. The dissection of bioelectric events as instructive signals enabling the orchestration of cell behaviors into large-scale coherent patterning programs will enrich on-going work in diverse areas of biology, as biophysical factors become incorporated into our systems-level understanding of cell interactions.
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Affiliation(s)
- Dany S Adams
- Department of Biology, and Center for Regenerative and Developmental Biology, Tufts University, 200 Boston Ave, Medford, MA 02155, USA
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Schwab A, Fabian A, Hanley PJ, Stock C. Role of ion channels and transporters in cell migration. Physiol Rev 2013; 92:1865-913. [PMID: 23073633 DOI: 10.1152/physrev.00018.2011] [Citation(s) in RCA: 315] [Impact Index Per Article: 28.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Cell motility is central to tissue homeostasis in health and disease, and there is hardly any cell in the body that is not motile at a given point in its life cycle. Important physiological processes intimately related to the ability of the respective cells to migrate include embryogenesis, immune defense, angiogenesis, and wound healing. On the other side, migration is associated with life-threatening pathologies such as tumor metastases and atherosclerosis. Research from the last ≈ 15 years revealed that ion channels and transporters are indispensable components of the cellular migration apparatus. After presenting general principles by which transport proteins affect cell migration, we will discuss systematically the role of channels and transporters involved in cell migration.
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Tseng AS, Levin M. Transducing bioelectric signals into epigenetic pathways during tadpole tail regeneration. Anat Rec (Hoboken) 2012; 295:1541-51. [PMID: 22933452 DOI: 10.1002/ar.22495] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2011] [Revised: 04/12/2012] [Accepted: 04/12/2012] [Indexed: 11/12/2022]
Abstract
One important component of the cell-cell communication that occurs during regenerative patterning is bioelectrical signaling. In particular, the regeneration of the tail in Xenopus laevis tadpoles both requires, and can be initiated at non-regenerative stages by, specific regulation of bioelectrical signaling (alteration in resting membrane potential and a subsequent change in sodium content of blastemal cells). Although standing gradients of transmembrane voltage and ion concentration can provide positional guidance and other morphogenetic cues, these biophysical parameters must be transduced into transcriptional responses within cells. A number of mechanisms have been described for linking slow voltage changes to gene expression, but recent data on the importance of epigenetic regulation for regeneration suggest a novel hypothesis: that sodium/butyrate transporters link ion flows to influx of small molecules needed to modify chromatin state. Here, we briefly review the data on bioelectricity in tadpole tail regeneration, present a technique for convenient alteration of transmembrane potential in vivo that does not require transgenes, show augmentation of regeneration in vivo by manipulation of voltage, and present new data in the Xenopus tail consistent with the hypothesis that the monocarboxlyate transporter SLC5A8 may link regeneration-relevant epigenetic modification with upstream changes in ion content.
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Affiliation(s)
- Ai-Sun Tseng
- Center for Regenerative and Developmental Biology and Department of Biology, Tufts University, Medford, Massachusetts, USA
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Quantifying interactions of β-synuclein and γ-synuclein with model membranes. J Mol Biol 2012; 423:528-39. [PMID: 22922472 DOI: 10.1016/j.jmb.2012.08.008] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2012] [Revised: 08/14/2012] [Accepted: 08/15/2012] [Indexed: 11/21/2022]
Abstract
The synucleins are a family of proteins involved in numerous neurodegenerative pathologies [α-synuclein and β-synuclein (βS)], as well as in various types of cancers [γ-synuclein (γS)]. While the connection between α-synuclein and Parkinson's disease is well established, recent evidence links point mutants of βS to dementia with Lewy bodies. Overexpression of γS has been associated with enhanced metastasis and cancer drug resistance. Despite their prevalence in such a variety of diseases, the native functions of the synucleins remain unclear. They have a lipid-binding motif in their N-terminal region, which suggests interactions with biological membranes in vivo. In this study, we used fluorescence correlation spectroscopy to monitor the binding properties of βS and γS to model membranes and to determine the free energy of the interactions. Our results show that the interactions are most strongly affected by the presence of both anionic lipids and bilayer curvature, while membrane fluidity plays a very minor role. Quantifying the lipid-binding properties of βS and γS provides additional insights into the underlying factors governing the protein-membrane interactions. Such insights not only are relevant to the native functions of these proteins but also highlight their contributions to pathological conditions that are either mediated or characterized by perturbations of these interactions.
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The plasma membrane potential and the organization of the actin cytoskeleton of epithelial cells. Int J Cell Biol 2012; 2012:121424. [PMID: 22315611 PMCID: PMC3272338 DOI: 10.1155/2012/121424] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2011] [Accepted: 10/08/2011] [Indexed: 12/22/2022] Open
Abstract
The establishment and maintenance of the polarized epithelial phenotype require a characteristic organization of the cytoskeletal components. There are many cellular effectors involved in the regulation of the cytoskeleton of epithelial cells. Recently, modifications in the plasma membrane potential (PMP) have been suggested to participate in the modulation of the cytoskeletal organization of epithelia. Here, we review evidence showing that changes in the PMP of diverse epithelial cells promote characteristic modifications in the cytoskeletal organization, with a focus on the actin cytoskeleton. The molecular paths mediating these effects may include voltage-sensitive integral membrane proteins and/or peripheral proteins sensitive to surface potentials. The voltage dependence of the cytoskeletal organization seems to have implications in several physiological processes, including epithelial wound healing and apoptosis.
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Levin M, Stevenson CG. Regulation of cell behavior and tissue patterning by bioelectrical signals: challenges and opportunities for biomedical engineering. Annu Rev Biomed Eng 2012; 14:295-323. [PMID: 22809139 PMCID: PMC10472538 DOI: 10.1146/annurev-bioeng-071811-150114] [Citation(s) in RCA: 129] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Achieving control over cell behavior and pattern formation requires molecular-level understanding of regulatory mechanisms. Alongside transcriptional networks and biochemical gradients, there functions an important system of cellular communication and control: transmembrane voltage gradients (V(mem)). Bioelectrical signals encoded in spatiotemporal changes of V(mem) control cell proliferation, migration, and differentiation. Moreover, endogenous bioelectrical gradients serve as instructive cues mediating anatomical polarity and other organ-level aspects of morphogenesis. In the past decade, significant advances in molecular physiology have enabled the development of new genetic and biophysical tools for the investigation and functional manipulation of bioelectric cues. Recent data implicate V(mem) as a crucial epigenetic regulator of patterning events in embryogenesis, regeneration, and cancer. We review new conceptual and methodological developments in this fascinating field. Bioelectricity offers a novel way of quantitatively understanding regulation of growth and form in vivo, and it reveals tractable, powerful control points that will enable truly transformative applications in bioengineering, regenerative medicine, and synthetic biology.
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Affiliation(s)
- Michael Levin
- Department of Biology, Center for Regenerative and Developmental Biology, Tufts University, Medford, Massachusetts 02155, USA.
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Abstract
All cells complete cell division by the process of cytokinesis. At the end of mitosis, eukaryotic cells accurately mark the site of division between the replicated genetic material and assemble a contractile ring comprised of myosin II, actin filaments and other proteins, which is attached to the plasma membrane. The myosin-actin interaction drives constriction of the contractile ring, forming a cleavage furrow (the so-called 'purse-string' model of cytokinesis). After furrowing is completed, the cells remain attached by a thin cytoplasmic bridge, filled with two anti-parallel arrays of microtubules with their plus-ends interdigitating in the midbody region. The cell then assembles the abscission machinery required for cleavage of the intercellular bridge, and so forms two genetically identical daughter cells. We now know much of the molecular detail of cytokinesis, including a list of potential genes/proteins involved, analysis of the function of some of these proteins, and the temporal order of their arrival at the cleavage site. Such studies reveal that membrane trafficking and/or remodelling appears to play crucial roles in both furrowing and abscission. In the present review, we assess studies of vesicular trafficking during cytokinesis, discuss the role of the lipid components of the plasma membrane and endosomes and their role in cytokinesis, and describe some novel molecules implicated in cytokinesis. The present review covers experiments performed mainly on tissue culture cells. We will end by considering how this mechanistic insight may be related to cytokinesis in other systems, and how other forms of cytokinesis may utilize similar aspects of the same machinery.
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Becchetti A. Ion channels and transporters in cancer. 1. Ion channels and cell proliferation in cancer. Am J Physiol Cell Physiol 2011; 301:C255-65. [DOI: 10.1152/ajpcell.00047.2011] [Citation(s) in RCA: 134] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Progress through the cell mitotic cycle requires precise timing of the intrinsic molecular steps and tight coordination with the environmental signals that maintain a cell into the proper physiological context. Because of their great functional flexibility, ion channels coordinate the upstream and downstream signals that converge on the cell cycle machinery. Both voltage- and ligand-gated channels have been implicated in the control of different cell cycle checkpoints in normal as well as neoplastic cells. Ion channels mediate the calcium signals that punctuate the mitotic process, the cell volume oscillations typical of cycling cells, and the exocytosis of autocrine or angiogenetic factors. Other functions of ion channels in proliferation are still matter of debate. These may or may not depend on ion transport, as the channel proteins can form macromolecular complexes with growth factor and cell adhesion receptors. Direct conformational coupling with the cytoplasmic regulatory proteins is also possible. Derangement or relaxed control of the above processes can promote neoplasia. Specific types of ion channels have turned out to participate in the different stages of the tumor progression, in which cell heterogeneity is increased by the selection of malignant cell clones expressing the ion channel types that better support unrestrained growth. However, a comprehensive mechanistic picture of the functional relations between ion channels and cell proliferation is yet not available, partly because of the considerable experimental challenges offered by studying these processes in living mammalian cells. No doubt, such studies will constitute one of the most fruitful research fields for the next generation of cell physiologists.
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Affiliation(s)
- Andrea Becchetti
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, Milano, Italy
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Callies C, Fels J, Liashkovich I, Kliche K, Jeggle P, Kusche-Vihrog K, Oberleithner H. Membrane potential depolarization decreases the stiffness of vascular endothelial cells. J Cell Sci 2011; 124:1936-42. [PMID: 21558418 DOI: 10.1242/jcs.084657] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The stiffness of vascular endothelial cells is crucial to mechanically withstand blood flow and, at the same time, to control deformation-dependent nitric oxide release. However, the regulation of mechanical stiffness is not yet understood. There is evidence that a possible regulator is the electrical plasma membrane potential difference. Using a novel technique that combines fluorescence-based membrane potential recordings with atomic force microscopy (AFM)-based stiffness measurements, the present study shows that membrane depolarization is associated with a decrease in the stiffness of endothelial cells. Three different depolarization protocols were applied, all of which led to a similar and significant decrease in cell stiffness, independently of changes in cell volume. Moreover, experiments using the actin-destabilizing agent cytochalasin D indicated that depolarization acts by affecting the cortical actin cytoskeleton. A model is proposed whereby a change of the electrical field across the plasma membrane is directly sensed by the submembranous actin network, regulating the actin polymerization:depolymerization ratio and thus cell stiffness. This depolarization-induced decrease in the stiffness of endothelial cells could play a role in flow-mediated nitric-oxide-dependent vasodilation.
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Affiliation(s)
- Chiara Callies
- Institute of Physiology II, University of Münster, Robert-Koch-Str. 27b, 48149 Münster, Germany.
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Abstract
In the last decades, imaging membrane potential has become a fruitful approach to study neural circuits, especially in invertebrate preparations with large, resilient neurons. At the same time, particularly in mammalian preparations, voltage imaging methods suffer from poor signal to noise and secondary side effects, and they fall short of providing single-cell resolution when imaging of the activity of neuronal populations. As an introduction to these techniques, we briefly review different voltage imaging methods (including organic fluorophores, SHG chromophores, genetic indicators, hybrid, nanoparticles, and intrinsic approaches) and illustrate some of their applications to neuronal biophysics and mammalian circuit analysis. We discuss their mechanisms of voltage sensitivity, from reorientation, electrochromic, or electro-optical phenomena to interaction among chromophores or membrane scattering, and highlight their advantages and shortcomings, commenting on the outlook for development of novel voltage imaging methods.
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Affiliation(s)
- Darcy S Peterka
- Department of Biological Sciences, Columbia University, New York, New York 10027, USA.
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Blackiston D, Adams DS, Lemire JM, Lobikin M, Levin M. Transmembrane potential of GlyCl-expressing instructor cells induces a neoplastic-like conversion of melanocytes via a serotonergic pathway. Dis Model Mech 2011; 4:67-85. [PMID: 20959630 PMCID: PMC3008964 DOI: 10.1242/dmm.005561] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2010] [Accepted: 08/23/2010] [Indexed: 12/14/2022] Open
Abstract
Understanding the mechanisms that coordinate stem cell behavior within the host is a high priority for developmental biology, regenerative medicine and oncology. Endogenous ion currents and voltage gradients function alongside biochemical cues during pattern formation and tumor suppression, but it is not known whether bioelectrical signals are involved in the control of stem cell progeny in vivo. We studied Xenopus laevis neural crest, an embryonic stem cell population that gives rise to many cell types, including melanocytes, and contributes to the morphogenesis of the face, heart and other complex structures. To investigate how depolarization of transmembrane potential of cells in the neural crest's environment influences its function in vivo, we manipulated the activity of the native glycine receptor chloride channel (GlyCl). Molecular-genetic depolarization of a sparse, widely distributed set of GlyCl-expressing cells non-cell-autonomously induces a neoplastic-like phenotype in melanocytes: they overproliferate, acquire an arborized cell shape and migrate inappropriately, colonizing numerous tissues in a metalloprotease-dependent fashion. A similar effect was observed in human melanocytes in culture. Depolarization of GlyCl-expressing cells induces these drastic changes in melanocyte behavior via a serotonin-transporter-dependent increase of extracellular serotonin (5-HT). These data reveal GlyCl as a molecular marker of a sparse and heretofore unknown cell population with the ability to specifically instruct neural crest derivatives, suggest transmembrane potential as a tractable signaling modality by which somatic cells can control stem cell behavior at considerable distance, identify a new biophysical aspect of the environment that confers a neoplastic-like phenotype upon stem cell progeny, reveal a pre-neural role for serotonin and its transporter, and suggest a novel strategy for manipulating stem cell behavior.
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Affiliation(s)
- Douglas Blackiston
- Center for Regenerative and Developmental Biology, and Biology Department, 200 Boston Avenue, Suite 4600, Tufts University, Medford, MA 02155, USA
- Department of Regenerative and Developmental Biology, Forsyth Institute, Boston, MA 02115, USA
| | - Dany S. Adams
- Center for Regenerative and Developmental Biology, and Biology Department, 200 Boston Avenue, Suite 4600, Tufts University, Medford, MA 02155, USA
| | - Joan M. Lemire
- Center for Regenerative and Developmental Biology, and Biology Department, 200 Boston Avenue, Suite 4600, Tufts University, Medford, MA 02155, USA
| | - Maria Lobikin
- Center for Regenerative and Developmental Biology, and Biology Department, 200 Boston Avenue, Suite 4600, Tufts University, Medford, MA 02155, USA
| | - Michael Levin
- Center for Regenerative and Developmental Biology, and Biology Department, 200 Boston Avenue, Suite 4600, Tufts University, Medford, MA 02155, USA
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50
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Matzke AJM, Weiger TM, Matzke M. Ion channels at the nucleus: electrophysiology meets the genome. MOLECULAR PLANT 2010; 3:642-52. [PMID: 20410254 PMCID: PMC2910552 DOI: 10.1093/mp/ssq013] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2010] [Accepted: 03/12/2010] [Indexed: 05/21/2023]
Abstract
The nuclear envelope is increasingly viewed from an electrophysiological perspective by researchers interested in signal transduction pathways that influence gene transcription and other processes in the nucleus. Here, we describe evidence for ion channels and transporters in the nuclear membranes and for possible ion gating by the nuclear pores. We argue that a systems-level understanding of cellular regulation is likely to require the assimilation of nuclear electrophysiology into molecular and biochemical signaling pathways.
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Affiliation(s)
- Antonius J M Matzke
- Gregor Mendel Institute of Molecular Plant Biology, Austrian Academy of Sciences, Dr. Bohr-Gasse 3, A-1030 Vienna, Austria.
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