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Chiu PL, Orjuela JD, de Groot BL, Aponte-Santamaría C, Walz T. Structure and dynamics of cholesterol-mediated aquaporin-0 arrays and implications for lipid rafts. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.05.16.540959. [PMID: 37292626 PMCID: PMC10245776 DOI: 10.1101/2023.05.16.540959] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Aquaporin-0 (AQP0) tetramers form square arrays in lens membranes through a yet unknown mechanism, but lens membranes are enriched in sphingomyelin and cholesterol. Here, we determined electron crystallographic structures of AQP0 in sphingomyelin/cholesterol membranes and performed molecular dynamics (MD) simulations to establish that the observed cholesterol positions represent those seen around an isolated AQP0 tetramer and that the AQP0 tetramer largely defines the location and orientation of most of its associated cholesterol molecules. At a high concentration, cholesterol increases the hydrophobic thickness of the annular lipid shell around AQP0 tetramers, which may thus cluster to mitigate the resulting hydrophobic mismatch. Moreover, neighboring AQP0 tetramers sandwich a cholesterol deep in the center of the membrane. MD simulations show that the association of two AQP0 tetramers is necessary to maintain the deep cholesterol in its position and that the deep cholesterol increases the force required to laterally detach two AQP0 tetramers, not only due to protein-protein contacts but also due to increased lipid-protein complementarity. Since each tetramer interacts with four such 'glue' cholesterols, avidity effects may stabilize larger arrays. The principles proposed to drive AQP0 array formation could also underlie protein clustering in lipid rafts.
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2
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Robayo-Amortegui H, Quintero-Altare A, Florez-Navas C, Serna-Palacios I, Súarez-Saavedra A, Buitrago-Bernal R, Casallas-Barrera JO. Fluid dynamics of life: exploring the physiology and importance of water in the critical illness. Front Med (Lausanne) 2024; 11:1368502. [PMID: 38745736 PMCID: PMC11092983 DOI: 10.3389/fmed.2024.1368502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2024] [Accepted: 04/12/2024] [Indexed: 05/16/2024] Open
Abstract
Water acknowledged as a vital component for life and the universal solvent, is crucial for diverse physiological processes in the human body. While essential for survival, the human body lacks the capacity to produce water, emphasizing the need for regular ingestion to maintain a homeostatic environment. The human body, predominantly composed of water, exhibits remarkable biochemical properties, playing a pivotal role in processes such as protein transport, thermoregulation, the cell cycle, and acid–base balance. This review delves into comprehending the molecular characteristics of water and its interactions within the human body. The article offers valuable insights into the intricate relationship between water and critical illness. Through a comprehensive exploration, it seeks to enhance our understanding of water’s pivotal role in sustaining overall human health.
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Affiliation(s)
- Henry Robayo-Amortegui
- Department of Critical Care Medicine, Fundación Clínica Shaio, Bogotá, DC, Colombia
- Department of Medicine, Critical Care Resident, Universidad de La Sabana, Chía Cundinamarca, Colombia
| | - Alejandro Quintero-Altare
- Department of Critical Care Medicine, Fundación Clínica Shaio, Bogotá, DC, Colombia
- Department of Medicine, Critical Care Resident, Universidad de La Sabana, Chía Cundinamarca, Colombia
| | - Catalina Florez-Navas
- Department of Critical Care Medicine, Fundación Clínica Shaio, Bogotá, DC, Colombia
- Department of Medicine, Critical Care Resident, Universidad de La Sabana, Chía Cundinamarca, Colombia
| | - Isacio Serna-Palacios
- Department of Medicine, Critical Care Resident, Universidad de La Sabana, Chía Cundinamarca, Colombia
| | | | - Ricardo Buitrago-Bernal
- Department of Critical Care Medicine, Fundación Clínica Shaio, Bogotá, DC, Colombia
- Exploratorium group, Fundación Clínica Shaio, Bogotá, DC, Colombia
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3
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Bassetto CAZ, Pfeffermann J, Yadav R, Strassgschwandtner S, Glasnov T, Bezanilla F, Pohl P. Photolipid excitation triggers depolarizing optocapacitive currents and action potentials. Nat Commun 2024; 15:1139. [PMID: 38326372 PMCID: PMC10850502 DOI: 10.1038/s41467-024-45403-y] [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: 08/23/2023] [Accepted: 01/22/2024] [Indexed: 02/09/2024] Open
Abstract
Optically-induced changes in membrane capacitance may regulate neuronal activity without requiring genetic modifications. Previously, they mainly relied on sudden temperature jumps due to light absorption by membrane-associated nanomaterials or water. Yet, nanomaterial targeting or the required high infrared light intensities obstruct broad applicability. Now, we propose a very versatile approach: photolipids (azobenzene-containing diacylglycerols) mediate light-triggered cellular de- or hyperpolarization. As planar bilayer experiments show, the respective currents emerge from millisecond-timescale changes in bilayer capacitance. UV light changes photolipid conformation, which awards embedding plasma membranes with increased capacitance and evokes depolarizing currents. They open voltage-gated sodium channels in cells, generating action potentials. Blue light reduces the area per photolipid, decreasing membrane capacitance and eliciting hyperpolarization. If present, mechanosensitive channels respond to the increased mechanical membrane tension, generating large depolarizing currents that elicit action potentials. Membrane self-insertion of administered photolipids and focused illumination allows cell excitation with high spatiotemporal control.
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Affiliation(s)
- Carlos A Z Bassetto
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL, 60637, USA
| | - Juergen Pfeffermann
- Institute of Biophysics, Johannes Kepler University Linz, Gruberstraße 40, 4020, Linz, Austria
| | - Rohit Yadav
- Institute of Biophysics, Johannes Kepler University Linz, Gruberstraße 40, 4020, Linz, Austria
| | | | - Toma Glasnov
- Institute of Chemistry, Karl-Franzens-University, Graz, Austria
| | - Francisco Bezanilla
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL, 60637, USA.
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile.
| | - Peter Pohl
- Institute of Biophysics, Johannes Kepler University Linz, Gruberstraße 40, 4020, Linz, Austria.
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4
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Wang Y, Han X, Deng L, Wang X. Tunneling nanotube-transmitted mechanical signal and its cellular response. Biochem Biophys Res Commun 2024; 693:149368. [PMID: 38091838 DOI: 10.1016/j.bbrc.2023.149368] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Accepted: 12/05/2023] [Indexed: 01/10/2024]
Abstract
Tunneling nanotubes (TNTs) are elastic tubular structures that physically link cells, facilitating the intercellular transfer of organelles, chemical signals, and electrical signals. Despite TNTs serving as a multifunctional pathway for cell-cell communication, the transmission of mechanical signals through TNTs and the response of TNT-connected cells to these forces remain unexplored. In this study, external mechanical forces were applied to induce TNT bending between rat kidney (NRK) cells using micromanipulation. These forces, transmitted via TNTs, induced reduced curvature of the actin cortex and increased membrane tension at the TNT-connected sites. Additionally, TNT bending results in an elevation of intracellular calcium levels in TNT-connected cells, a response attenuated by gadolinium ions, a non-selective mechanosensitive calcium channel blocker. The degree of TNT deflection positively correlated with decreased actin cortex curvature and increased calcium levels. Furthermore, stretching TNT due to the separation of TNT-connected cells resulted in decreased actin cortex curvature and increased intracellular calcium in TNT-connected cells. The levels of these cellular responses depended on the length changes of TNTs. Moreover, TNT connections influence cell migration by regulating cell rotation, which involves the activation of mechanosensitive calcium channels. In conclusion, our study revealed the transmission of mechanical signals through TNTs and the subsequent responses of TNT-connected cells, highlighting a previously unrecognized communication function of TNTs. This research provides valuable insights into the role of TNTs in long-distance intercellular mechanical signaling.
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Affiliation(s)
- Yan Wang
- Institute of Biomedical Engineering and Health Sciences, Changzhou, Jiangsu, China; School of Pharmacy, Changzhou University, Changzhou, Jiangsu, China
| | - Xiaoning Han
- Institute of Biomedical Engineering and Health Sciences, Changzhou, Jiangsu, China; School of Medical and Health Engineering, Changzhou, Jiangsu, China
| | - Linhong Deng
- Institute of Biomedical Engineering and Health Sciences, Changzhou, Jiangsu, China; School of Medical and Health Engineering, Changzhou, Jiangsu, China.
| | - Xiang Wang
- Institute of Biomedical Engineering and Health Sciences, Changzhou, Jiangsu, China; School of Medical and Health Engineering, Changzhou, Jiangsu, China.
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5
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Sanfeliu-Cerdán N, Català-Castro F, Mateos B, Garcia-Cabau C, Ribera M, Ruider I, Porta-de-la-Riva M, Canals-Calderón A, Wieser S, Salvatella X, Krieg M. A MEC-2/stomatin condensate liquid-to-solid phase transition controls neuronal mechanotransduction during touch sensing. Nat Cell Biol 2023; 25:1590-1599. [PMID: 37857834 PMCID: PMC10635833 DOI: 10.1038/s41556-023-01247-0] [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: 07/22/2022] [Accepted: 09/01/2023] [Indexed: 10/21/2023]
Abstract
A growing body of work suggests that the material properties of biomolecular condensates ensuing from liquid-liquid phase separation change with time. How this aging process is controlled and whether the condensates with distinct material properties can have different biological functions is currently unknown. Using Caenorhabditis elegans as a model, we show that MEC-2/stomatin undergoes a rigidity phase transition from fluid-like to solid-like condensates that facilitate transport and mechanotransduction, respectively. This switch is triggered by the interaction between the SH3 domain of UNC-89 (titin/obscurin) and MEC-2. We suggest that this rigidity phase transition has a physiological role in frequency-dependent force transmission in mechanosensitive neurons during body wall touch. Our data demonstrate a function for the liquid and solid phases of MEC-2/stomatin condensates in facilitating transport or mechanotransduction, and a previously unidentified role for titin homologues in neurons.
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Affiliation(s)
- Neus Sanfeliu-Cerdán
- ICFO - Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, Castelldefels (Barcelona), Spain
| | - Frederic Català-Castro
- ICFO - Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, Castelldefels (Barcelona), Spain
| | - Borja Mateos
- Institute for Research in Biomedicine, The Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Carla Garcia-Cabau
- Institute for Research in Biomedicine, The Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Maria Ribera
- Institute for Research in Biomedicine, The Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Iris Ruider
- ICFO - Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, Castelldefels (Barcelona), Spain
| | - Montserrat Porta-de-la-Riva
- ICFO - Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, Castelldefels (Barcelona), Spain
| | - Adrià Canals-Calderón
- Institute for Research in Biomedicine, The Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Stefan Wieser
- ICFO - Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, Castelldefels (Barcelona), Spain
| | - Xavier Salvatella
- Institute for Research in Biomedicine, The Barcelona Institute of Science and Technology, Barcelona, Spain.
- ICREA, Barcelona, Spain.
| | - Michael Krieg
- ICFO - Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, Castelldefels (Barcelona), Spain.
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6
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Bassetto CAZ, Pfeffermann J, Yadav R, Strassgschwandtner S, Glasnov T, Bezanilla F, Pohl P. Photolipid excitation triggers depolarizing optocapacitive currents and action potentials. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.11.552849. [PMID: 37645959 PMCID: PMC10462005 DOI: 10.1101/2023.08.11.552849] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/31/2023]
Abstract
Optically-induced changes in membrane capacitance may regulate neuronal activity without requiring genetic modifications. Previously, they mainly relied on sudden temperature jumps due to light absorption by membrane-associated nanomaterials or water. Yet, nanomaterial targeting or the required high infrared light intensities obstruct broad applicability. Now, we propose a very versatile approach: photolipids (azobenzene-containing diacylglycerols) mediate light-triggered cellular de- or hyperpolarization. As planar bilayer experiments show, the respective currents emerge from millisecond-timescale changes in bilayer capacitance. UV light changes photolipid conformation, which awards embedding plasma membranes with increased capacitance and evokes depolarizing currents. They open voltage-gated sodium channels in cells, generating action potentials. Blue light reduces the area per photolipid, decreasing membrane capacitance and eliciting hyperpolarization. If present, mechanosensitive channels respond to the increased mechanical membrane tension, generating large depolarizing currents that elicit action potentials. Membrane self-insertion of administered photolipids and focused illumination allows cell excitation with high spatiotemporal control.
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Affiliation(s)
- Carlos A. Z. Bassetto
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL 60637, USA
| | - Juergen Pfeffermann
- Institute of Biophysics, Johannes Kepler University Linz, Gruberstraße 40, 4020 Linz, Austria
| | - Rohit Yadav
- Institute of Biophysics, Johannes Kepler University Linz, Gruberstraße 40, 4020 Linz, Austria
| | | | - Toma Glasnov
- Institute of Chemistry, Karl-Franzens-University, Graz, Austria
| | - Francisco Bezanilla
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL 60637, USA
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Peter Pohl
- Institute of Biophysics, Johannes Kepler University Linz, Gruberstraße 40, 4020 Linz, Austria
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7
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Martinac B, Kung C. The force-from-lipid principle and its origin, a ‘ what is true for E. coli is true for the elephant’ refrain. J Neurogenet 2022; 36:44-54. [DOI: 10.1080/01677063.2022.2097674] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Boris Martinac
- Molecular Cardiology and Biophysics Division, Victor Chang Cardiac Research Institute, Sydney, Australia
- School of Clinical Medicine, UNSW Medicine & Health, St Vincent's Healthcare Clinical Campus, Faculty of Medicine and Health, University of New South Wales, Sydney, Australia
| | - Ching Kung
- Laboratory of Molecular Biology and the Department of Genetics, University of Wisconsin–Madison, Madison, WI, USA
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8
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Shrestha A, Kahraman O, Haselwandter CA. Mechanochemical coupling of lipid organization and protein function through membrane thickness deformations. Phys Rev E 2022; 105:054410. [PMID: 35706253 DOI: 10.1103/physreve.105.054410] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Accepted: 05/06/2022] [Indexed: 06/15/2023]
Abstract
Cell membranes are composed of a great variety of protein and lipid species with distinct unperturbed hydrophobic thicknesses. To achieve hydrophobic matching, the lipid bilayer tends to deform around membrane proteins so as to match the protein hydrophobic thickness at bilayer-protein interfaces. Such protein-induced distortions of the lipid bilayer hydrophobic thickness incur a substantial energy cost that depends critically on the bilayer-protein hydrophobic mismatch, while distinct conformational states of membrane proteins often show distinct hydrophobic thicknesses. As a result, hydrophobic interactions between membrane proteins and lipids can yield a rich interplay of lipid-protein organization and transitions in protein conformational state. We combine here the membrane elasticity theory of protein-induced lipid bilayer thickness deformations with the Landau-Ginzburg theory of lipid domain formation to systematically explore the coupling between local lipid organization, lipid and protein hydrophobic thickness, and protein-induced lipid bilayer thickness deformations in membranes with heterogeneous lipid composition. We allow for a purely mechanical coupling of lipid and protein composition through the energetics of protein-induced lipid bilayer thickness deformations as well as a chemical coupling driven by preferential interactions between particular lipid and protein species. We find that the resulting lipid-protein organization can endow membrane proteins with diverse and controlled mechanical environments that, via protein-induced lipid bilayer thickness deformations, can strongly influence protein function. The theoretical approach employed here provides a general framework for the quantitative prediction of how membrane thickness deformations influence the joint organization and function of lipids and proteins in cell membranes.
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Affiliation(s)
- Ahis Shrestha
- Department of Physics and Astronomy and Department of Quantitative and Computational Biology, University of Southern California, Los Angeles, California 90089, USA
| | - Osman Kahraman
- Department of Physics and Astronomy and Department of Quantitative and Computational Biology, University of Southern California, Los Angeles, California 90089, USA
| | - Christoph A Haselwandter
- Department of Physics and Astronomy and Department of Quantitative and Computational Biology, University of Southern California, Los Angeles, California 90089, USA
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9
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Fatty acids as biomodulators of Piezo1 mediated glial mechanosensitivity in Alzheimer's disease. Life Sci 2022; 297:120470. [DOI: 10.1016/j.lfs.2022.120470] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Revised: 12/09/2021] [Accepted: 03/06/2022] [Indexed: 11/18/2022]
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10
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Luo M, Cai G, Ho KKY, Wen K, Tong Z, Deng L, Liu AP. Compression enhances invasive phenotype and matrix degradation of breast Cancer cells via Piezo1 activation. BMC Mol Cell Biol 2022; 23:1. [PMID: 34979904 PMCID: PMC8722159 DOI: 10.1186/s12860-021-00401-6] [Citation(s) in RCA: 35] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Accepted: 12/17/2021] [Indexed: 12/14/2022] Open
Abstract
Background Uncontrolled growth in solid breast cancer generates mechanical compression that may drive the cancer cells into a more invasive phenotype, but little is known about how such compression affects the key events and corresponding regulatory mechanisms associated with invasion of breast cancer cells including cellular behaviors and matrix degradation. Results Here we show that compression enhanced invasion and matrix degradation of breast cancer cells. We also identified Piezo1 as the putative mechanosensitive cellular component that transmitted compression to not only enhance the invasive phenotype, but also induce calcium influx and downstream Src signaling. Furthermore, we demonstrated that Piezo1 was mainly localized in caveolae, and both Piezo1 expression and compression-enhanced invasive phenotype of the breast cancer cells were reduced when caveolar integrity was compromised by either knocking down caveolin1 expression or depleting cholesterol content. Conclusions Taken together, our data indicate that mechanical compression activates Piezo1 channels to mediate enhanced breast cancer cell invasion, which involves both cellular events and matrix degradation. This may be a critical mechanotransduction pathway during breast cancer metastasis, and thus potentially a novel therapeutic target for the disease. Supplementary Information The online version contains supplementary material available at 10.1186/s12860-021-00401-6.
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Affiliation(s)
- Mingzhi Luo
- Institute of Biomedical Engineering and Health Sciences, Changzhou University, Changzhou, Jiangsu, People's Republic of China.,Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI, USA
| | - Grace Cai
- Applied Physics Program, University of Michigan, Ann Arbor, MI, USA
| | - Kenneth K Y Ho
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI, USA.,Present address: Center for Molecular Imaging, Department of Radiology, University of Michigan, Ann Arbor, MI, USA
| | - Kang Wen
- Institute of Biomedical Engineering and Health Sciences, Changzhou University, Changzhou, Jiangsu, People's Republic of China
| | - Zhaowen Tong
- Applied Physics Program, University of Michigan, Ann Arbor, MI, USA
| | - Linhong Deng
- Institute of Biomedical Engineering and Health Sciences, Changzhou University, Changzhou, Jiangsu, People's Republic of China.
| | - Allen P Liu
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI, USA. .,Applied Physics Program, University of Michigan, Ann Arbor, MI, USA. .,Department of Biophysics, University of Michigan, Ann Arbor, MI, USA. .,Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA. .,Cellular and Molecular Biology Program, University of Michigan, Ann Arbor, MI, USA.
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11
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Lakk M, Hoffmann GF, Gorusupudi A, Enyong E, Lin A, Bernstein PS, Toft-Bertelsen T, MacAulay N, Elliott MH, Križaj D. Membrane cholesterol regulates TRPV4 function, cytoskeletal expression, and the cellular response to tension. J Lipid Res 2021; 62:100145. [PMID: 34710431 PMCID: PMC8633027 DOI: 10.1016/j.jlr.2021.100145] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Revised: 10/08/2021] [Accepted: 10/19/2021] [Indexed: 02/06/2023] Open
Abstract
Despite the association of cholesterol with debilitating pressure-related diseases such as glaucoma, heart disease, and diabetes, its role in mechanotransduction is not well understood. We investigated the relationship between mechanical strain, free membrane cholesterol, actin cytoskeleton, and the stretch-activated transient receptor potential vanilloid isoform 4 (TRPV4) channel in human trabecular meshwork (TM) cells. Physiological levels of cyclic stretch resulted in time-dependent decreases in membrane cholesterol/phosphatidylcholine ratio and upregulation of stress fibers. Depleting free membrane cholesterol with m-β-cyclodextrin (MβCD) augmented TRPV4 activation by the agonist GSK1016790A, swelling and strain, with the effects reversed by cholesterol supplementation. MβCD increased membrane expression of TRPV4, caveolin-1, and flotillin. TRPV4 did not colocalize or interact with caveolae or lipid rafts, apart from a truncated ∼75 kDa variant partially precipitated by a caveolin-1 antibody. MβCD induced currents in TRPV4-expressing Xenopus laevis oocytes. Thus, membrane cholesterol regulates trabecular transduction of mechanical information, with TRPV4 channels mainly located outside the cholesterol-enriched membrane domains. Moreover, the biomechanical milieu itself shapes the lipid content of TM membranes. Diet, cholesterol metabolism, and mechanical stress might modulate the conventional outflow pathway and intraocular pressure in glaucoma and diabetes in part by modulating TM mechanosensing.
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Affiliation(s)
- Monika Lakk
- Department of Ophthalmology & Visual Sciences, University of Utah School of Medicine, Salt Lake City, UT, USA
| | - Grace F Hoffmann
- Department of Ophthalmology & Visual Sciences, University of Utah School of Medicine, Salt Lake City, UT, USA
| | - Aruna Gorusupudi
- Department of Ophthalmology & Visual Sciences, University of Utah School of Medicine, Salt Lake City, UT, USA
| | - Eric Enyong
- Dean A. McGee Eye Institute, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Amy Lin
- Department of Ophthalmology & Visual Sciences, University of Utah School of Medicine, Salt Lake City, UT, USA
| | - Paul S Bernstein
- Department of Ophthalmology & Visual Sciences, University of Utah School of Medicine, Salt Lake City, UT, USA
| | | | - Nanna MacAulay
- Department of Neuroscience, University of Copenhagen, Copenhagen, Denmark
| | - Michael H Elliott
- Dean A. McGee Eye Institute, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - David Križaj
- Department of Ophthalmology & Visual Sciences, University of Utah School of Medicine, Salt Lake City, UT, USA; Department of Bioengineering, University of Utah, Salt Lake City, UT, USA; Department of Neurobiology, University of Utah, Salt Lake City, UT, USA.
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12
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Loh D, Reiter RJ. Melatonin: Regulation of Biomolecular Condensates in Neurodegenerative Disorders. Antioxidants (Basel) 2021; 10:1483. [PMID: 34573116 PMCID: PMC8465482 DOI: 10.3390/antiox10091483] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Revised: 09/10/2021] [Accepted: 09/13/2021] [Indexed: 12/12/2022] Open
Abstract
Biomolecular condensates are membraneless organelles (MLOs) that form dynamic, chemically distinct subcellular compartments organizing macromolecules such as proteins, RNA, and DNA in unicellular prokaryotic bacteria and complex eukaryotic cells. Separated from surrounding environments, MLOs in the nucleoplasm, cytoplasm, and mitochondria assemble by liquid-liquid phase separation (LLPS) into transient, non-static, liquid-like droplets that regulate essential molecular functions. LLPS is primarily controlled by post-translational modifications (PTMs) that fine-tune the balance between attractive and repulsive charge states and/or binding motifs of proteins. Aberrant phase separation due to dysregulated membrane lipid rafts and/or PTMs, as well as the absence of adequate hydrotropic small molecules such as ATP, or the presence of specific RNA proteins can cause pathological protein aggregation in neurodegenerative disorders. Melatonin may exert a dominant influence over phase separation in biomolecular condensates by optimizing membrane and MLO interdependent reactions through stabilizing lipid raft domains, reducing line tension, and maintaining negative membrane curvature and fluidity. As a potent antioxidant, melatonin protects cardiolipin and other membrane lipids from peroxidation cascades, supporting protein trafficking, signaling, ion channel activities, and ATPase functionality during condensate coacervation or dissolution. Melatonin may even control condensate LLPS through PTM and balance mRNA- and RNA-binding protein composition by regulating N6-methyladenosine (m6A) modifications. There is currently a lack of pharmaceuticals targeting neurodegenerative disorders via the regulation of phase separation. The potential of melatonin in the modulation of biomolecular condensate in the attenuation of aberrant condensate aggregation in neurodegenerative disorders is discussed in this review.
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Affiliation(s)
- Doris Loh
- Independent Researcher, Marble Falls, TX 78654, USA
| | - Russel J. Reiter
- Department of Cellular and Structural Biology, UT Health Science Center, San Antonio, TX 78229, USA
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13
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Joshi V, Strege PR, Farrugia G, Beyder A. Mechanotransduction in gastrointestinal smooth muscle cells: role of mechanosensitive ion channels. Am J Physiol Gastrointest Liver Physiol 2021; 320:G897-G906. [PMID: 33729004 PMCID: PMC8202201 DOI: 10.1152/ajpgi.00481.2020] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Mechanosensation, the ability to properly sense mechanical stimuli and transduce them into physiologic responses, is an essential determinant of gastrointestinal (GI) function. Abnormalities in this process result in highly prevalent GI functional and motility disorders. In the GI tract, several cell types sense mechanical forces and transduce them into electrical signals, which elicit specific cellular responses. Some mechanosensitive cells like sensory neurons act as specialized mechanosensitive cells that detect forces and transduce signals into tissue-level physiological reactions. Nonspecialized mechanosensitive cells like smooth muscle cells (SMCs) adjust their function in response to forces. Mechanosensitive cells use various mechanoreceptors and mechanotransducers. Mechanoreceptors detect and convert force into electrical and biochemical signals, and mechanotransducers amplify and direct mechanoreceptor responses. Mechanoreceptors and mechanotransducers include ion channels, specialized cytoskeletal proteins, cell junction molecules, and G protein-coupled receptors. SMCs are particularly important due to their role as final effectors for motor function. Myogenic reflex-the ability of smooth muscle to contract in response to stretch rapidly-is a critical smooth muscle function. Such rapid mechanotransduction responses rely on mechano-gated and mechanosensitive ion channels, which alter their ion pores' opening in response to force, allowing fast electrical and Ca2+ responses. Although GI SMCs express a variety of such ion channels, their identities remain unknown. Recent advancements in electrophysiological, genetic, in vivo imaging, and multi-omic technologies broaden our understanding of how SMC mechano-gated and mechanosensitive ion channels regulate GI functions. This review discusses GI SMC mechanosensitivity's current developments with a particular emphasis on mechano-gated and mechanosensitive ion channels.
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Affiliation(s)
- Vikram Joshi
- 1Division of Gastroenterology & Hepatology, Enteric NeuroScience Program (ENSP), Mayo Clinic, Rochester, Minnesota
| | - Peter R. Strege
- 1Division of Gastroenterology & Hepatology, Enteric NeuroScience Program (ENSP), Mayo Clinic, Rochester, Minnesota
| | - Gianrico Farrugia
- 1Division of Gastroenterology & Hepatology, Enteric NeuroScience Program (ENSP), Mayo Clinic, Rochester, Minnesota,2Department of Physiology & Biomedical Engineering, Mayo Clinic, Rochester, Minnesota
| | - Arthur Beyder
- 1Division of Gastroenterology & Hepatology, Enteric NeuroScience Program (ENSP), Mayo Clinic, Rochester, Minnesota,2Department of Physiology & Biomedical Engineering, Mayo Clinic, Rochester, Minnesota
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14
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Effertz T, Moser T, Oliver D. Recent advances in cochlear hair cell nanophysiology: subcellular compartmentalization of electrical signaling in compact sensory cells. Fac Rev 2021; 9:24. [PMID: 33659956 PMCID: PMC7886071 DOI: 10.12703/r/9-24] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
In recent years, genetics, physiology, and structural biology have advanced into the molecular details of the sensory physiology of auditory hair cells. Inner hair cells (IHCs) and outer hair cells (OHCs) mediate two key functions: active amplification and non-linear compression of cochlear vibrations by OHCs and sound encoding by IHCs at their afferent synapses with the spiral ganglion neurons. OHCs and IHCs share some molecular physiology, e.g. mechanotransduction at the apical hair bundles, ribbon-type presynaptic active zones, and ionic conductances in the basolateral membrane. Unique features enabling their specific function include prestin-based electromotility of OHCs and indefatigable transmitter release at the highest known rates by ribbon-type IHC active zones. Despite their compact morphology, the molecular machineries that either generate electrical signals or are driven by these signals are essentially all segregated into local subcellular structures. This review provides a brief account on recent insights into the molecular physiology of cochlear hair cells with a specific focus on organization into membrane domains.
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Affiliation(s)
- Thomas Effertz
- InnerEarLab, Department of Otorhinolaryngology, University Medical Center Göttingen, 37099 Göttingen, Germany
| | - Tobias Moser
- Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, 37099 Göttingen, Germany
- Auditory Neuroscience Group, Max Planck Institute for Experimental Medicine, 37075 Göttingen, Germany
- Synaptic Nanophysiology Group, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany
- Multiscale Bioimaging Cluster of Excellence (MBExC), University of Göttingen, 37075 Göttingen, Germany
| | - Dominik Oliver
- Institute for Physiology and Pathophysiology, Philipps University, Deutschhausstraße 2, 35037 Marburg, Germany
- Center for Mind, Brain and Behavior (CMBB), Universities of Marburg and Giessen, Germany
- DFG Research Training Group, Membrane Plasticity in Tissue Development and Remodelling, GRK 2213, Philipps University, Marburg, Germany
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15
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Yang J, Zhang Y, Qin M, Cheng W, Wang W, Cao Y. Understanding and Regulating Cell-Matrix Interactions Using Hydrogels of Designable Mechanical Properties. J Biomed Nanotechnol 2021; 17:149-168. [PMID: 33785089 DOI: 10.1166/jbn.2021.3026] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Similar to natural tissues, hydrogels contain abundant water, so they are considered as promising biomaterials for studying the influence of the mechanical properties of extracellular matrices (ECM) on various cell functions. In recent years, the growing research on cellular mechanical response has revealed that many cell functions, including cell spreading, migration, tumorigenesis and differentiation, are related to the mechanical properties of ECM. Therefore, how cells sense and respond to the extracellular mechanical environment has gained considerable attention. In these studies, hydrogels are widely used as the in vitro model system. Hydrogels of tunable stiffness, viscoelasticity, degradability, plasticity, and dynamical properties have been engineered to reveal how cells respond to specific mechanical features. In this review, we summarize recent process in this research direction and specifically focus on the influence of the mechanical properties of the ECM on cell functions, how cells sense and respond to the extracellular mechanical environment, and approaches to adjusting the stiffness of hydrogels.
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Affiliation(s)
- Jiapeng Yang
- Key Laboratory of Intelligent Optical Sensing and Integration, National Laboratory of Solid State Microstructure, and Department of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Yu Zhang
- Key Laboratory of Intelligent Optical Sensing and Integration, National Laboratory of Solid State Microstructure, and Department of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Meng Qin
- Key Laboratory of Intelligent Optical Sensing and Integration, National Laboratory of Solid State Microstructure, and Department of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Wei Cheng
- Department of Oral Implantology Nanjing Stomatological Hospital, Medical School of Nanjing University, Nanjing 210008, China
| | - Wei Wang
- Key Laboratory of Intelligent Optical Sensing and Integration, National Laboratory of Solid State Microstructure, and Department of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Yi Cao
- Key Laboratory of Intelligent Optical Sensing and Integration, National Laboratory of Solid State Microstructure, and Department of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
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16
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Shrestha A, Kahraman O, Haselwandter CA. Regulation of membrane proteins through local heterogeneity in lipid bilayer thickness. Phys Rev E 2021; 102:060401. [PMID: 33465991 DOI: 10.1103/physreve.102.060401] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Accepted: 11/06/2020] [Indexed: 11/07/2022]
Abstract
Cell membranes show an intricate organization of lipids and membrane proteins into domains with distinct composition and hydrophobic thickness. Using mechanosensitive ion channels as a model system, we employ the membrane elasticity theory of lipid-protein interactions together with the Landau-Ginzburg theory of lipid domain formation to quantify protein-induced lipid bilayer thickness deformations in lipid bilayers with heterogeneous hydrophobic thickness. We show that protein-induced lipid bilayer thickness deformations yield, without any assumptions about preferential interactions between particular lipid and protein species, organization of lipids and membrane proteins according to their preferred hydrophobic thickness, and couple the conformational states of membrane proteins to the local membrane composition. Our calculations suggest that protein-induced lipid bilayer thickness deformations endow proteins in cell membranes with diverse and controlled mechanical environments that, in turn, allow targeted regulation of membrane proteins.
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Affiliation(s)
- Ahis Shrestha
- Department of Physics & Astronomy and Department of Biological Sciences, University of Southern California, Los Angeles, California 90089, USA
| | - Osman Kahraman
- Department of Physics & Astronomy and Department of Biological Sciences, University of Southern California, Los Angeles, California 90089, USA
| | - Christoph A Haselwandter
- Department of Physics & Astronomy and Department of Biological Sciences, University of Southern California, Los Angeles, California 90089, USA
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17
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Li S, Yan Z. Mechanotransduction Ion Channels in Hearing and Touch. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1349:371-385. [DOI: 10.1007/978-981-16-4254-8_17] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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18
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Discoveries in structure and physiology of mechanically activated ion channels. Nature 2020; 587:567-576. [PMID: 33239794 DOI: 10.1038/s41586-020-2933-1] [Citation(s) in RCA: 259] [Impact Index Per Article: 64.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Accepted: 08/19/2020] [Indexed: 01/24/2023]
Abstract
The ability to sense physical forces is conserved across all organisms. Cells convert mechanical stimuli into electrical or chemical signals via mechanically activated ion channels. In recent years, the identification of new families of mechanosensitive ion channels-such as PIEZO and OSCA/TMEM63 channels-along with surprising insights into well-studied mechanosensitive channels have driven further developments in the mechanotransduction field. Several well-characterized mechanosensory roles such as touch, blood-pressure sensing and hearing are now linked with primary mechanotransducers. Unanticipated roles of mechanical force sensing continue to be uncovered. Furthermore, high-resolution structures representative of nearly every family of mechanically activated channel described so far have underscored their diversity while advancing our understanding of the biophysical mechanisms of pressure sensing. Here we summarize recent discoveries in the physiology and structures of known mechanically activated ion channel families and discuss their implications for understanding the mechanisms of mechanical force sensing.
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19
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Cox CD, Bavi N, Martinac B. Biophysical Principles of Ion-Channel-Mediated Mechanosensory Transduction. Cell Rep 2020; 29:1-12. [PMID: 31577940 DOI: 10.1016/j.celrep.2019.08.075] [Citation(s) in RCA: 113] [Impact Index Per Article: 28.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Revised: 06/09/2019] [Accepted: 08/22/2019] [Indexed: 01/12/2023] Open
Abstract
Recent rapid progress in the field of mechanobiology has been driven by novel emerging tools and methodologies and growing interest from different scientific disciplines. Specific progress has been made toward understanding how cell mechanics is linked to intracellular signaling and the regulation of gene expression in response to a variety of mechanical stimuli. There is a direct link between the mechanoreceptors at the cell surface and intracellular biochemical signaling, which in turn controls downstream effector molecules. Among the mechanoreceptors in the cell membrane, mechanosensitive (MS) ion channels are essential for the ultra-rapid (millisecond) transduction of mechanical stimuli into biologically relevant signals. The three decades of research on mechanosensitive channels resulted in the formulation of two basic principles of mechanosensitive channel gating: force-from-lipids and force-from-filament. In this review, we revisit the biophysical principles that underlie the innate force-sensing ability of mechanosensitive channels as contributors to the force-dependent evolution of life forms.
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Affiliation(s)
- Charles D Cox
- Victor Chang Cardiac Research Institute, Lowy Packer Building, Darlinghurst, NSW 2010, Australia; St. Vincent's Clinical School, University of New South Wales, Darlinghurst, NSW 2010, Australia
| | - Navid Bavi
- Institute for Biophysical Dynamics, University of Chicago, Chicago, IL 60637, USA
| | - Boris Martinac
- Victor Chang Cardiac Research Institute, Lowy Packer Building, Darlinghurst, NSW 2010, Australia; St. Vincent's Clinical School, University of New South Wales, Darlinghurst, NSW 2010, Australia.
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20
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Romero LO, Caires R, Nickolls AR, Chesler AT, Cordero-Morales JF, Vásquez V. A dietary fatty acid counteracts neuronal mechanical sensitization. Nat Commun 2020; 11:2997. [PMID: 32561714 PMCID: PMC7305179 DOI: 10.1038/s41467-020-16816-2] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Accepted: 05/26/2020] [Indexed: 02/06/2023] Open
Abstract
PIEZO2 is the essential transduction channel for touch discrimination, vibration, and proprioception. Mice and humans lacking Piezo2 experience severe mechanosensory and proprioceptive deficits and fail to develop tactile allodynia. Bradykinin, a proalgesic agent released during inflammation, potentiates PIEZO2 activity. Molecules that decrease PIEZO2 function could reduce heightened touch responses during inflammation. Here, we find that the dietary fatty acid margaric acid (MA) decreases PIEZO2 function in a dose-dependent manner. Chimera analyses demonstrate that the PIEZO2 beam is a key region tuning MA-mediated channel inhibition. MA reduces neuronal action potential firing elicited by mechanical stimuli in mice and rat neurons and counteracts PIEZO2 sensitization by bradykinin. Finally, we demonstrate that this saturated fatty acid decreases PIEZO2 currents in touch neurons derived from human induced pluripotent stem cells. Our findings report on a natural product that inhibits PIEZO2 function and counteracts neuronal mechanical sensitization and reveal a key region for channel inhibition.
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Affiliation(s)
- Luis O Romero
- 71S. Manassas St. Department of Physiology, College of Medicine, University of Tennessee Health Science Center, Memphis, TN, 38103, USA
- Integrated Biomedical Sciences Graduate Program, College of Graduate Health Sciences, Memphis, TN, 38103, USA
| | - Rebeca Caires
- 71S. Manassas St. Department of Physiology, College of Medicine, University of Tennessee Health Science Center, Memphis, TN, 38103, USA
| | - Alec R Nickolls
- National Center for Complementary and Integrative Health, National Institutes of Health, Bethesda, MD, 20892, USA
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Alexander T Chesler
- National Center for Complementary and Integrative Health, National Institutes of Health, Bethesda, MD, 20892, USA.
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, 20892, USA.
| | - Julio F Cordero-Morales
- 71S. Manassas St. Department of Physiology, College of Medicine, University of Tennessee Health Science Center, Memphis, TN, 38103, USA.
| | - Valeria Vásquez
- 71S. Manassas St. Department of Physiology, College of Medicine, University of Tennessee Health Science Center, Memphis, TN, 38103, USA.
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21
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Johnson LR, Battle AR, Martinac B. Remembering Mechanosensitivity of NMDA Receptors. Front Cell Neurosci 2019; 13:533. [PMID: 31866826 PMCID: PMC6906178 DOI: 10.3389/fncel.2019.00533] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2019] [Accepted: 11/18/2019] [Indexed: 12/14/2022] Open
Abstract
An increase in post-synaptic Ca2+ conductance through activation of the ionotropic N-methyl-D-aspartate receptor (NMDAR) and concomitant structural changes are essential for the initiation of long-term potentiation (LTP) and memory formation. Memories can be initiated by coincident events, as occurs in classical conditioning, where the NMDAR can act as a molecular coincidence detector. Binding of glutamate and glycine, together with depolarization of the postsynaptic cell membrane to remove the Mg2+ channel pore block, results in NMDAR opening for Ca2+ conductance. Accumulating evidence has implicated both force-from-lipids and protein tethering mechanisms for mechanosensory transduction in NMDAR, which has been demonstrated by both, membrane stretch and application of amphipathic molecules such as arachidonic acid (AA). The contribution of mechanosensitivity to memory formation and consolidation may be to increase activity of the NMDAR leading to facilitated memory formation. In this review we look back at the progress made toward understanding the physiological and pathological role of NMDA receptor channels in mechanobiology of the nervous system and consider these findings in like of their potential functional implications for memory formation. We examine recent studies identifying mechanisms of both NMDAR and other mechanosensitive channels and discuss functional implications including gain control of NMDA opening probability. Mechanobiology is a rapidly growing area of biology with many important implications for understanding form, function and pathology in the nervous system.
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Affiliation(s)
- Luke R Johnson
- Victor Chang Cardiac Research Institute, Darlinghurst, NSW, Australia.,St. Vincent's Clinical School, University of New South Wales, Darlinghurst, NSW, Australia.,Division of Psychology, School of Medicine, University of Tasmania, Launceston, TAS, Australia.,Department of Psychiatry, Center for the Study of Traumatic Stress, Uniformed Services University of the Health Sciences, Bethesda, MD, United States.,School of Biomedical Sciences, Institute of Health and Biomedical Innovation (IHBI), Queensland University of Technology, Brisbane, QLD, Australia
| | - Andrew R Battle
- School of Biomedical Sciences, Institute of Health and Biomedical Innovation (IHBI), Queensland University of Technology, Brisbane, QLD, Australia.,Prince Charles Hospital Northside Clinical Unit, School of Clinical Medicine, The University of Queensland, Brisbane, QLD, Australia.,Translational Research Institute, Woolloongabba, QLD, Australia
| | - Boris Martinac
- Victor Chang Cardiac Research Institute, Darlinghurst, NSW, Australia.,St. Vincent's Clinical School, University of New South Wales, Darlinghurst, NSW, Australia
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22
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Reyes-Pardo H, Sánchez-Herrera DP. Mechanosensitive ion channel inhibitors promote the stiffening of the plasma membrane of mouse sensory neurons. SOFT MATTER 2019; 15:8320-8328. [PMID: 31565715 DOI: 10.1039/c9sm01230c] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The mechanosensitivity of cells depends on the lipid-protein interactions of the plasma membrane. Affectations in the lipid region of the plasma membrane affect the transduction of mechanical forces, and any molecule that modifies the biophysical integrity of the lipid bilayer can alter the mechanical activity of the proteins inside the membrane. To understand whether inhibitors of mechanically activated ion channels affect the mechanical properties of the plasma membrane, we evaluated the rigidity of the membrane of sensory neurons of the DRG of mice using a variant of the scanning ion conductance microscopy method, which allows us to calculate the Young's modulus of individual cells before and after the perfusion of different doses of Gd3+, ruthenium red and GsMTx-4. Our results suggest that these molecules compromise the membrane by increasing the Young's modulus value, which indicates that the membrane becomes more rigid; these compounds act through different mechanisms and by a non-specific manner, each one shows a certain preference for specific cell subpopulations, depending on their cell size and their reactivity to isolectin B4. Our results support the idea that the biophysical properties that result from the interactions that arise in the membranes are part of the mechanotransduction process.
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Affiliation(s)
- Humberto Reyes-Pardo
- Unidad Monterrey, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Apodaca, Nuevo León, Mexico.
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23
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How Caenorhabditis elegans Senses Mechanical Stress, Temperature, and Other Physical Stimuli. Genetics 2019; 212:25-51. [PMID: 31053616 PMCID: PMC6499529 DOI: 10.1534/genetics.118.300241] [Citation(s) in RCA: 67] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Accepted: 03/04/2019] [Indexed: 12/30/2022] Open
Abstract
Caenorhabditis elegans lives in a complex habitat in which they routinely experience large fluctuations in temperature, and encounter physical obstacles that vary in size and composition. Their habitat is shared by other nematodes, by beneficial and harmful bacteria, and nematode-trapping fungi. Not surprisingly, these nematodes can detect and discriminate among diverse environmental cues, and exhibit sensory-evoked behaviors that are readily quantifiable in the laboratory at high resolution. Their ability to perform these behaviors depends on <100 sensory neurons, and this compact sensory nervous system together with powerful molecular genetic tools has allowed individual neuron types to be linked to specific sensory responses. Here, we describe the sensory neurons and molecules that enable C. elegans to sense and respond to physical stimuli. We focus primarily on the pathways that allow sensation of mechanical and thermal stimuli, and briefly consider this animal’s ability to sense magnetic and electrical fields, light, and relative humidity. As the study of sensory transduction is critically dependent upon the techniques for stimulus delivery, we also include a section on appropriate laboratory methods for such studies. This chapter summarizes current knowledge about the sensitivity and response dynamics of individual classes of C. elegans mechano- and thermosensory neurons from in vivo calcium imaging and whole-cell patch-clamp electrophysiology studies. We also describe the roles of conserved molecules and signaling pathways in mediating the remarkably sensitive responses of these nematodes to mechanical and thermal cues. These studies have shown that the protein partners that form mechanotransduction channels are drawn from multiple superfamilies of ion channel proteins, and that signal transduction pathways responsible for temperature sensing in C. elegans share many features with those responsible for phototransduction in vertebrates.
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Mallis RJ, Brazin KN, Duke-Cohan JS, Hwang W, Wang JH, Wagner G, Arthanari H, Lang MJ, Reinherz EL. NMR: an essential structural tool for integrative studies of T cell development, pMHC ligand recognition and TCR mechanobiology. JOURNAL OF BIOMOLECULAR NMR 2019; 73:319-332. [PMID: 30815789 PMCID: PMC6693947 DOI: 10.1007/s10858-019-00234-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2018] [Accepted: 02/06/2019] [Indexed: 05/05/2023]
Abstract
Early studies of T cell structural biology using X-ray crystallography, surface plasmon resonance (SPR) and isothermal titration calorimetry (ITC) focused on a picture of the αβT cell receptor (αβTCR) component domains and their cognate ligands (peptides bound to MHC molecules, i.e. pMHCs) as static interaction partners. Moving forward requires integrating this corpus of data with dynamic technologies such as NMR, molecular dynamics (MD) simulations and real-time single molecule (SM) studies exemplified by optical tweezers (OT). NMR bridges relevant timescales and provides the potential for an all-atom dynamic description of αβTCR components prior to and during interactions with binding partners. SM techniques have opened up vistas in understanding the non-equilibrium nature of T cell signaling through the introduction of force-mediated binding measurements into the paradigm for T cell function. In this regard, bioforces consequent to T-lineage cell motility are now perceived as placing piconewton (pN)-level loads on single receptor-pMHC bonds to impact structural change and αβT-lineage biology, including peptide discrimination, cellular activation, and developmental progression. We discuss herein essential NMR technologies in illuminating the role of ligand binding in the preT cell receptor (preTCR), the αβTCR developmental precursor, and convergence of NMR, SM and MD data in advancing our comprehension of T cell development. More broadly we review the central hypothesis that the αβTCR is a mechanosensor, fostered by breakthrough NMR-based structural insights. Collectively, elucidating dynamic aspects through the integrative use of NMR, SM, and MD shall advance fundamental appreciation of the mechanism of T cell signaling as well as inform translational efforts in αβTCR and chimeric T cell (CAR-T) immunotherapies and T cell vaccinology.
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Affiliation(s)
- Robert J Mallis
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, 02115, USA
- Department of Dermatology, Harvard Medical School, Boston, MA, 02115, USA
- Laboratory of Immunobiology, Dana-Farber Cancer Institute, Boston, MA, 02115, USA
| | - Kristine N Brazin
- Laboratory of Immunobiology, Dana-Farber Cancer Institute, Boston, MA, 02115, USA
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, 02115, USA
- Department of Medicine, Harvard Medical School, Boston, MA, 02115, USA
| | - Jonathan S Duke-Cohan
- Laboratory of Immunobiology, Dana-Farber Cancer Institute, Boston, MA, 02115, USA
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, 02115, USA
- Department of Medicine, Harvard Medical School, Boston, MA, 02115, USA
| | - Wonmuk Hwang
- Department of Biomedical Engineering, Texas A&M University, College Station, TX, 77843, USA
- Department of Materials Science & Engineering, Texas A&M University, College Station, TX, 77843, USA
- School of Computational Sciences, Korea Institute for Advanced Study, Seoul, 02455, Republic of Korea
| | - Jia-Huai Wang
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, 02115, USA
- Laboratory of Immunobiology, Dana-Farber Cancer Institute, Boston, MA, 02115, USA
- Department of Pediatrics, Harvard Medical School, Boston, MA, 02115, USA
| | - Gerhard Wagner
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, 02115, USA
| | - Haribabu Arthanari
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, 02115, USA.
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, 02115, USA.
| | - Matthew J Lang
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, TN, 37235, USA.
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN, 37235, USA.
| | - Ellis L Reinherz
- Laboratory of Immunobiology, Dana-Farber Cancer Institute, Boston, MA, 02115, USA.
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, 02115, USA.
- Department of Medicine, Harvard Medical School, Boston, MA, 02115, USA.
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25
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Losasso V, Hsiao YW, Martelli F, Winn MD, Crain J. Modulation of Antimicrobial Peptide Potency in Stressed Lipid Bilayers. PHYSICAL REVIEW LETTERS 2019; 122:208103. [PMID: 31172786 DOI: 10.1103/physrevlett.122.208103] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Indexed: 06/09/2023]
Abstract
It is shown that the tendency of an archetypal antimicrobial peptide to insert into and perforate a simple lipid bilayer is strongly modulated by tensile stress in the membrane. The results, obtained through molecular dynamics simulations, have been demonstrated with several lipid compositions and appear to be general, although quantitative details differ. The findings imply that the potency of antimicrobial peptides may not be a purely intrinsic chemical property and, instead, depends on the mechanical state of the target membrane.
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Affiliation(s)
- Valeria Losasso
- Daresbury Laboratory, STFC, Daresbury, Warrington, England WA4 4AD, United Kingdom
| | - Ya-Wen Hsiao
- Daresbury Laboratory, STFC, Daresbury, Warrington, England WA4 4AD, United Kingdom
| | - Fausto Martelli
- IBM Research, Hartree Centre, Daresbury, England WA4 4AD, United Kingdom
| | - Martyn D Winn
- Daresbury Laboratory, STFC, Daresbury, Warrington, England WA4 4AD, United Kingdom
| | - Jason Crain
- IBM Research, Hartree Centre, Daresbury, England WA4 4AD, United Kingdom
- Dept. of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, England
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26
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Neuronal stretch reception – Making sense of the mechanosense. Exp Cell Res 2019; 378:104-112. [DOI: 10.1016/j.yexcr.2019.01.028] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Revised: 01/14/2019] [Accepted: 01/17/2019] [Indexed: 02/06/2023]
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27
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Romero LO, Massey AE, Mata-Daboin AD, Sierra-Valdez FJ, Chauhan SC, Cordero-Morales JF, Vásquez V. Dietary fatty acids fine-tune Piezo1 mechanical response. Nat Commun 2019; 10:1200. [PMID: 30867417 PMCID: PMC6416271 DOI: 10.1038/s41467-019-09055-7] [Citation(s) in RCA: 134] [Impact Index Per Article: 26.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Accepted: 02/18/2019] [Indexed: 12/18/2022] Open
Abstract
Mechanosensitive ion channels rely on membrane composition to transduce physical stimuli into electrical signals. The Piezo1 channel mediates mechanoelectrical transduction and regulates crucial physiological processes, including vascular architecture and remodeling, cell migration, and erythrocyte volume. The identity of the membrane components that modulate Piezo1 function remain largely unknown. Using lipid profiling analyses, we here identify dietary fatty acids that tune Piezo1 mechanical response. We find that margaric acid, a saturated fatty acid present in dairy products and fish, inhibits Piezo1 activation and polyunsaturated fatty acids (PUFAs), present in fish oils, modulate channel inactivation. Force measurements reveal that margaric acid increases membrane bending stiffness, whereas PUFAs decrease it. We use fatty acid supplementation to abrogate the phenotype of gain-of-function Piezo1 mutations causing human dehydrated hereditary stomatocytosis. Beyond Piezo1, our findings demonstrate that cell-intrinsic lipid profile and changes in the fatty acid metabolism can dictate the cell's response to mechanical cues.
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Affiliation(s)
- Luis O Romero
- Department of Physiology, College of Medicine, University of Tennessee Health Science Center, 71S. Manassas St., Memphis, TN, 38163, USA
| | - Andrew E Massey
- Department of Pharmaceutical Sciences and Institute of Biomarker and Molecular Therapeutics (IBMT), College of Pharmacy, University of Tennessee Health Science Center, 881 Madison Ave., Memphis, TN, 38163, USA
| | - Alejandro D Mata-Daboin
- Department of Physiology, College of Medicine, University of Tennessee Health Science Center, 71S. Manassas St., Memphis, TN, 38163, USA
| | - Francisco J Sierra-Valdez
- Department of Physiology, College of Medicine, University of Tennessee Health Science Center, 71S. Manassas St., Memphis, TN, 38163, USA
- Centro de Investigación Biomédica, Hospital Zambrano Hellion, TecSalud, Ave. Batallon de San Patricio 112, 66278, San Pedro Garza García, Nuevo León, Mexico
- Tecnólogico de Monterrey, Escuela de Ingeniería y Ciencias, Ave. Eugenio Garza Sada 2501 Sur, 64849, Monterrey, Nuevo León, Mexico
| | - Subhash C Chauhan
- Department of Pharmaceutical Sciences and Institute of Biomarker and Molecular Therapeutics (IBMT), College of Pharmacy, University of Tennessee Health Science Center, 881 Madison Ave., Memphis, TN, 38163, USA
| | - Julio F Cordero-Morales
- Department of Physiology, College of Medicine, University of Tennessee Health Science Center, 71S. Manassas St., Memphis, TN, 38163, USA
| | - Valeria Vásquez
- Department of Physiology, College of Medicine, University of Tennessee Health Science Center, 71S. Manassas St., Memphis, TN, 38163, USA.
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An ATG16L1-dependent pathway promotes plasma membrane repair and limits Listeria monocytogenes cell-to-cell spread. Nat Microbiol 2018; 3:1472-1485. [PMID: 30478389 DOI: 10.1038/s41564-018-0293-5] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2018] [Accepted: 10/12/2018] [Indexed: 12/21/2022]
Abstract
Plasma membrane integrity is essential for the viability of eukaryotic cells. In response to bacterial pore-forming toxins, disrupted regions of the membrane are rapidly repaired. However, the pathways that mediate plasma membrane repair are unclear. Here we show that autophagy-related (ATG) protein ATG16L1 and its binding partners ATG5 and ATG12 are required for plasma membrane repair through a pathway independent of macroautophagy. ATG16L1 is required for lysosome fusion with the plasma membrane and blebbing responses that promote membrane repair. ATG16L1 deficiency causes accumulation of cholesterol in lysosomes that contributes to defective membrane repair. Cell-to-cell spread by Listeria monocytogenes requires membrane damage by the bacterial toxin listeriolysin O, which is restricted by ATG16L1-dependent membrane repair. Cells harbouring the ATG16L1 T300A allele associated with inflammatory bowel disease were also found to accumulate cholesterol and be defective in repair, linking a common inflammatory disease to plasma membrane integrity. Thus, plasma membrane repair could be an important therapeutic target for the treatment of bacterial infections and inflammatory disorders.
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Maneshi MM, Ziegler L, Sachs F, Hua SZ, Gottlieb PA. Enantiomeric Aβ peptides inhibit the fluid shear stress response of PIEZO1. Sci Rep 2018; 8:14267. [PMID: 30250223 PMCID: PMC6155315 DOI: 10.1038/s41598-018-32572-2] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Accepted: 09/06/2018] [Indexed: 01/23/2023] Open
Abstract
Traumatic brain injury (TBI) elevates Abeta (Aβ) peptides in the brain and cerebral spinal fluid. Aβ peptides are amphipathic molecules that can modulate membrane mechanics. Because the mechanosensitive cation channel PIEZO1 is gated by membrane tension and curvature, it prompted us to test the effects of Aβ on PIEZO1. Using precision fluid shear stress as a stimulus, we found that Aβ monomers inhibit PIEZO1 at femtomolar to picomolar concentrations. The Aβ oligomers proved much less potent. The effect of Aβs on Piezo gating did not involve peptide-protein interactions since the D and L enantiomers had similar effects. Incubating a fluorescent derivative of Aβ and a fluorescently tagged PIEZO1, we showed that Aβ can colocalize with PIEZO1, suggesting that they both had an affinity for particular regions of the bilayer. To better understand the PIEZO1 inhibitory effects of Aβ, we examined their effect on wound healing. We observed that over-expression of PIEZO1 in HEK293 cells increased cell migration velocity ~10-fold, and both enantiomeric Aβ peptides and GsMTx4 independently inhibited migration, demonstrating involvement of PIEZO1 in cell motility. As part of the motility study we examined the correlation of PIEZO1 function with tension in the cytoskeleton using a genetically encoded fluorescent stress probe. Aβ peptides increased resting stress in F-actin, and is correlated with Aβ block of PIEZO1-mediated Ca2+ influx. Aβ inhibition of PIEZO1 in the absence of stereospecific peptide-protein interactions shows that Aβ peptides modulate both cell membrane and cytoskeletal mechanics to control PIEZO1-triggered Ca2+ influx.
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Affiliation(s)
- Mohammad M Maneshi
- Department of Physiology and Biophysics, 302 Cary Hall, State University of New York at Buffalo, Buffalo, NY, 14214, USA
- Department of Mechanical and Aerospace Engineering, 340 Jarvis Hall, State University of New York at Buffalo, Buffalo, New York, 14260, USA
- 745 N Fairbanks, Tarry 7-718, Feinberg School of Medicine, Chicago, IL, 60611, USA
| | - Lynn Ziegler
- Department of Physiology and Biophysics, 302 Cary Hall, State University of New York at Buffalo, Buffalo, NY, 14214, USA
| | - Frederick Sachs
- Department of Physiology and Biophysics, 302 Cary Hall, State University of New York at Buffalo, Buffalo, NY, 14214, USA
| | - Susan Z Hua
- Department of Physiology and Biophysics, 302 Cary Hall, State University of New York at Buffalo, Buffalo, NY, 14214, USA
- Department of Mechanical and Aerospace Engineering, 340 Jarvis Hall, State University of New York at Buffalo, Buffalo, New York, 14260, USA
| | - Philip A Gottlieb
- Department of Physiology and Biophysics, 302 Cary Hall, State University of New York at Buffalo, Buffalo, NY, 14214, USA.
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Miller JJ, Aoki K, Moehring F, Murphy CA, O’Hara CL, Tiemeyer M, Stucky CL, Dahms NM. Neuropathic pain in a Fabry disease rat model. JCI Insight 2018; 3:99171. [PMID: 29563343 PMCID: PMC5926911 DOI: 10.1172/jci.insight.99171] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Accepted: 02/07/2018] [Indexed: 02/06/2023] Open
Abstract
Fabry disease, the most common lysosomal storage disease, affects multiple organs and results in a shortened life span. This disease is caused by a deficiency of the lysosomal enzyme α-galactosidase A, which leads to glycosphingolipid accumulation in many cell types. Neuropathic pain is an early and severely debilitating symptom in patients with Fabry disease, but the cellular and molecular mechanisms that cause the pain are unknown. We generated a rat model of Fabry disease, the first nonmouse model to our knowledge. Fabry rats had substantial serum and tissue accumulation of α-galactosyl glycosphingolipids and had pronounced mechanical pain behavior. Additionally, Fabry rat dorsal root ganglia displayed global N-glycan alterations, sensory neurons were laden with inclusions, and sensory neuron somata exhibited prominent sensitization to mechanical force. We found that the cation channel transient receptor potential ankyrin 1 (TRPA1) is sensitized in Fabry rat sensory neurons and that TRPA1 antagonism reversed the behavioral mechanical sensitization. This study points toward TRPA1 as a potentially novel target to treat the pain experienced by patients with Fabry disease.
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Affiliation(s)
- James J. Miller
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - Kazuhiro Aoki
- Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia, USA
| | - Francie Moehring
- Department of Cell Biology, Neurobiology, & Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - Carly A. Murphy
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - Crystal L. O’Hara
- Department of Cell Biology, Neurobiology, & Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - Michael Tiemeyer
- Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia, USA
| | - Cheryl L. Stucky
- Department of Cell Biology, Neurobiology, & Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - Nancy M. Dahms
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
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Ridone P, Grage SL, Patkunarajah A, Battle AR, Ulrich AS, Martinac B. "Force-from-lipids" gating of mechanosensitive channels modulated by PUFAs. J Mech Behav Biomed Mater 2017; 79:158-167. [PMID: 29304430 DOI: 10.1016/j.jmbbm.2017.12.026] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2017] [Revised: 12/20/2017] [Accepted: 12/22/2017] [Indexed: 12/15/2022]
Abstract
The level of fatty acid saturation in phospholipids is a crucial determinant of the biophysical properties of the lipid bilayer. Integral membrane proteins are sensitive to changes of their bilayer environment such that their activities and localization can be profoundly affected. When incorporated into phospholipids of mammalian cells, poly-unsaturated fatty acids (PUFAs) determine the mechanical properties of the bilayer thereby affecting several membrane-associated functions such as endo- and exo-cytosis and ion channel/membrane receptor signalling cascades. In order to understand how membrane tension is propagated through poly-unsaturated bilayers, we characterized the effect of lipid saturation on liposome reconstituted MscS and MscL, the two bacterial mechanosensitive ion channels that have for many years served as models of ion- channel-mediated mechanotransduction. The combination of NMR and patch clamp experiments in this study demonstrate that bilayer thinning is the main responsible factor for the modulation of the MscL threshold of activation while a change in transbilayer pressure profile is indicated as the main factor behind the observed modulation of the MscS kinetics. Together, our data offer a novel insight into how the structural shape differences between the two types of mechanosensitive channels determine their differential modulation by poly-unsaturated phospholipids and thus lay the foundation for future functional studies of eukaryotic ion channels involved in the physiology of mechanosensory transduction processes in mammalian cells. SUMMARY Mechanosensitive channels MscL and MscS are differentially modulated by poly-unsaturated fatty acids in lipid bilayers. MscL becomes sensitized because of increased hydrophobic mismatch while MscS open state is stabilized due to changes in the bilayer lateral pressure profile determined by NMR.
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Affiliation(s)
- Pietro Ridone
- Victor Chang Cardiac Research Institute, Darlinghurst, NSW 2010, Australia
| | - Stephan L Grage
- Institute for Biological Interfaces IBG-2, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Amrutha Patkunarajah
- School of Medical Sciences, University of New South Wales, Kensington, Sydney 2052, Australia
| | - Andrew R Battle
- Translational Research Institute (TRI) and Institute of Health and Biomedical Innovation (IHBI), School of Biomedical Sciences, Queensland University of Technology (QUT), Brisbane, QLD 4000, Australia
| | - Anne S Ulrich
- Institute for Biological Interfaces IBG-2, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Boris Martinac
- Victor Chang Cardiac Research Institute, Darlinghurst, NSW 2010, Australia; St Vincent's Clinical School, University of New South Wales, Darlinghurst, NSW 2010, Australia.
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Solé-Magdalena A, Martínez-Alonso M, Coronado CA, Junquera LM, Cobo J, Vega JA. Molecular basis of dental sensitivity: The odontoblasts are multisensory cells and express multifunctional ion channels. Ann Anat 2017; 215:20-29. [PMID: 28954208 DOI: 10.1016/j.aanat.2017.09.006] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2017] [Revised: 08/22/2017] [Accepted: 09/10/2017] [Indexed: 12/26/2022]
Abstract
Odontoblasts are the dental pulp cells responsible for the formation of dentin. In addition, accumulating data strongly suggest that they can also function as sensory cells that mediate the early steps of mechanical, thermic, and chemical dental sensitivity. This assumption is based on the expression of different families of ion channels involved in various modalities of sensitivity and the release of putative neurotransmitters in response to odontoblast stimulation which are able to act on pulp sensory nerve fibers. This review updates the current knowledge on the expression of transient-potential receptor ion channels and acid-sensing ion channels in odontoblasts, nerve fibers innervating them and trigeminal sensory neurons, as well as in pulp cells. Moreover, the innervation of the odontoblasts and the interrelationship been odontoblasts and nerve fibers mediated by neurotransmitters was also revisited. These data might provide the basis for novel therapeutic approaches for the treatment of dentin sensibility and/or dental pain.
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Affiliation(s)
- A Solé-Magdalena
- Departamento de Morfología y Biología Celular Universidad de Oviedo, Spain
| | - M Martínez-Alonso
- Departamento de Morfología y Biología Celular Universidad de Oviedo, Spain
| | - C A Coronado
- Facultad de Ciencias de la Salud, Universidad Autónoma de Chile, Temuco, Chile
| | - L M Junquera
- Departamento de Especialidades Médico-Quirúrgicas, Universidad de Oviedo, Spain; Servicio de Cirugía Maxilofacial, Hospital Universitario Central de Asturias, Oviedo, Spain
| | - J Cobo
- Departamento de Especialidades Médico-Quirúrgicas, Universidad de Oviedo, Spain; Instituto Asturiano de Odontología, Oviedo, Spain
| | - J A Vega
- Departamento de Morfología y Biología Celular Universidad de Oviedo, Spain; Facultad de Ciencias de la Salud, Universidad Autónoma de Chile, Temuco, Chile.
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Electron cryo-microscopy structure of the mechanotransduction channel NOMPC. Nature 2017; 547:118-122. [PMID: 28658211 DOI: 10.1038/nature22981] [Citation(s) in RCA: 148] [Impact Index Per Article: 21.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Accepted: 05/11/2017] [Indexed: 12/12/2022]
Abstract
Mechanosensory transduction for senses such as proprioception, touch, balance, acceleration, hearing and pain relies on mechanotransduction channels, which convert mechanical stimuli into electrical signals in specialized sensory cells. How force gates mechanotransduction channels is a central question in the field, for which there are two major models. One is the membrane-tension model: force applied to the membrane generates a change in membrane tension that is sufficient to gate the channel, as in the bacterial MscL channel and certain eukaryotic potassium channels. The other is the tether model: force is transmitted via a tether to gate the channel. The transient receptor potential (TRP) channel NOMPC is important for mechanosensation-related behaviours such as locomotion, touch and sound sensation across different species including Caenorhabditis elegans, Drosophila and zebrafish. NOMPC is the founding member of the TRPN subfamily, and is thought to be gated by tethering of its ankyrin repeat domain to microtubules of the cytoskeleton. Thus, a goal of studying NOMPC is to reveal the underlying mechanism of force-induced gating, which could serve as a paradigm of the tether model. NOMPC fulfils all the criteria that apply to mechanotransduction channels and has 29 ankyrin repeats, the largest number among TRP channels. A key question is how the long ankyrin repeat domain is organized as a tether that can trigger channel gating. Here we present a de novo atomic structure of Drosophila NOMPC determined by single-particle electron cryo-microscopy. Structural analysis suggests that the ankyrin repeat domain of NOMPC resembles a helical spring, suggesting its role of linking mechanical displacement of the cytoskeleton to the opening of the channel. The NOMPC architecture underscores the basis of translating mechanical force into an electrical signal within a cell.
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Abstract
Neurons allocated to sense organs respond rapidly to mechanical signals dictating behavioral responses at the organism level. The receptors that transduce these signals, and underlie these senses, are mechanically gated channels. Research on mechanosensation over the past decade, employing in many cases Drosophila as a model, has focused in typifying these receptors and in exploring the different ways, depending on context, in which these mechanosensors are modulated. In this review, we discuss first what we have learned from Drosophila on these mechanisms and we describe the different mechanosensory organs present in the Drosophila larvae and adult. Secondly, we focus on the progress obtained by studying the fly on the characterization of the mechanosensory crosstalk underlying complex behaviors like motor coordination. Finally, turning to a cellular level, we summarize what is known on the mechanical properties and sensing capabilities of neural cells and how they may affect neural physiology and pathology.
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Affiliation(s)
- Katerina Karkali
- Instituto de Biología Molecular de Barcelona, Consejo Superior de Investigaciones Científicas, Parc Cientific de Barcelona, Baldiri Reixac 10, 08028 Barcelona, Spain
| | - Enrique Martin-Blanco
- Instituto de Biología Molecular de Barcelona, Consejo Superior de Investigaciones Científicas, Parc Cientific de Barcelona, Baldiri Reixac 10, 08028 Barcelona, Spain.
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Abstract
Osmosensory neurons are specialized cells activated by increases in blood osmolality to trigger thirst, secretion of the antidiuretic hormone vasopressin, and elevated sympathetic tone during dehydration. In addition to multiple extrinsic factors modulating their activity, osmosensory neurons are intrinsically osmosensitive, as they are activated by increased osmolality in the absence of neighboring cells or synaptic contacts. This intrinsic osmosensitivity is a mechanical process associated with osmolality-induced changes in cell volume. This review summarises recent findings revealing molecular mechanisms underlying the mechanical activation of osmosensory neurons and highlighting important roles of microtubules, actin, and mechanosensitive ion channels in this process.
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36
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Gerth K, Lin F, Menzel W, Krishnamoorthy P, Stenzel I, Heilmann M, Heilmann I. Guilt by Association: A Phenotype-Based View of the Plant Phosphoinositide Network. ANNUAL REVIEW OF PLANT BIOLOGY 2017; 68:349-374. [PMID: 28125287 DOI: 10.1146/annurev-arplant-042916-041022] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Eukaryotic membranes contain small amounts of phospholipids that have regulatory effects on the physiological functions of cells, tissues, and organs. Phosphoinositides (PIs)-the phosphorylated derivatives of phosphatidylinositol-are one example of such regulatory lipids. Although PIs were described in plants decades ago, their contribution to the regulation of physiological processes in plants is not well understood. In the past few years, evidence has emerged that PIs are essential for plant function and development. Recently reported phenotypes associated with the perturbation of different PIs suggest that some subgroups of PIs influence specific processes. Although the molecular targets of PI-dependent regulation in plants are largely unknown, the effects of perturbed PI metabolism can be used to propose regulatory modules that involve particular downstream targets of PI regulation. This review summarizes phenotypes associated with the perturbation of the plant PI network to categorize functions and suggest possible downstream targets of plant PI regulation.
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Affiliation(s)
- Katharina Gerth
- Department of Cellular Biochemistry, Institute of Biochemistry and Biotechnology, Martin Luther University Halle-Wittenberg, 06120 Halle (Saale), Germany; , , , , , ,
| | - Feng Lin
- Department of Cellular Biochemistry, Institute of Biochemistry and Biotechnology, Martin Luther University Halle-Wittenberg, 06120 Halle (Saale), Germany; , , , , , ,
| | - Wilhelm Menzel
- Department of Cellular Biochemistry, Institute of Biochemistry and Biotechnology, Martin Luther University Halle-Wittenberg, 06120 Halle (Saale), Germany; , , , , , ,
| | - Praveen Krishnamoorthy
- Department of Cellular Biochemistry, Institute of Biochemistry and Biotechnology, Martin Luther University Halle-Wittenberg, 06120 Halle (Saale), Germany; , , , , , ,
| | - Irene Stenzel
- Department of Cellular Biochemistry, Institute of Biochemistry and Biotechnology, Martin Luther University Halle-Wittenberg, 06120 Halle (Saale), Germany; , , , , , ,
| | - Mareike Heilmann
- Department of Cellular Biochemistry, Institute of Biochemistry and Biotechnology, Martin Luther University Halle-Wittenberg, 06120 Halle (Saale), Germany; , , , , , ,
| | - Ingo Heilmann
- Department of Cellular Biochemistry, Institute of Biochemistry and Biotechnology, Martin Luther University Halle-Wittenberg, 06120 Halle (Saale), Germany; , , , , , ,
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Dohno C, Makishi S, Nakatani K, Contera S. Amphiphilic DNA tiles for controlled insertion and 2D assembly on fluid lipid membranes: the effect on mechanical properties. NANOSCALE 2017; 9:3051-3058. [PMID: 28186523 DOI: 10.1039/c6nr07084a] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Future lipid membrane-associated DNA nanostructures are expected to find applications ranging from synthetic biology to nanomedicine. Here we have designed and synthesized DNA tiles and modified them with amphiphilic covalent moieties. dod-DEG groups, which consist of a hydrophilic diethylene glycol (DEG) and a hydrophobic dodecyl group, are introduced at the phosphate backbone to create amphiphilic DNA strands which are subsequently introduced into one face of the DNA tiles. In this way the tile becomes able to stably bind to lipid membranes by insertion of the hydrophobic groups inside the bilayer core. The functionalized tiles do not aggregate in solution. Our results show that these amphiphilic DNA tiles can bind and assemble into 2D lattices on both gel and fluid lipid bilayers. The binding of the DNA structures to membranes is dependent on the lipid phase of the membrane, the concentration of Mg2+ cations, the length of the amphiphilic modifications to the DNA as well as on the density of the modifications within the tile. Atomic force microscopy-based force spectroscopy is used to investigate the effect of the inserted DNA tiles on the mechanical properties of the lipid membranes. The results indicate that the insertion of DNA tiles produces an approx. 20% increase of the bilayer breakthrough force.
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Affiliation(s)
- Chikara Dohno
- Department of Regulatory Bioorganic Chemistry, The Institute of Scientific and Industrial Research (ISIR), Osaka University, Osaka, Ibaraki 567-0047, Japan. and PRESTO, Japan Science and Technology Agency, 4-1-8 Honcho Kawaguchi, Saitama 332-0012, Japan
| | - Shingo Makishi
- Department of Regulatory Bioorganic Chemistry, The Institute of Scientific and Industrial Research (ISIR), Osaka University, Osaka, Ibaraki 567-0047, Japan.
| | - Kazuhiko Nakatani
- Department of Regulatory Bioorganic Chemistry, The Institute of Scientific and Industrial Research (ISIR), Osaka University, Osaka, Ibaraki 567-0047, Japan.
| | - Sonia Contera
- Clarendon Laboratory, Physics Department, University of Oxford, Oxford, OX1 3PU, UK.
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40
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Kinetic disruption of lipid rafts is a mechanosensor for phospholipase D. Nat Commun 2016; 7:13873. [PMID: 27976674 PMCID: PMC5171650 DOI: 10.1038/ncomms13873] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Accepted: 11/04/2016] [Indexed: 12/24/2022] Open
Abstract
The sensing of physical force, mechanosensation, underlies two of five human senses—touch and hearing. How transduction of force in a membrane occurs remains unclear. We asked if a biological membrane could employ kinetic energy to transduce a signal absent tension. Here we show that lipid rafts are dynamic compartments that inactivate the signalling enzyme phospholipase D2 (PLD2) by sequestering the enzyme from its substrate. Mechanical disruption of the lipid rafts activates PLD2 by mixing the enzyme with its substrate to produce the signalling lipid phosphatidic acid (PA). We calculate a latency time of <650 μs for PLD activation by mixing. Our results establish a fast, non-tension mechanism for mechanotransduction where disruption of ordered lipids initiates a mechanosensitive signal for cell growth through mechanical mixing.
Mechanosensation by biological membranes can be relayed by mechanical tension to ion channels. Here the authors show that phospholipase D (PLD) is activated by mechanical disruption of lipid rafts which allows PLD to mix with its substrate in the lipid membrane, and propose a kinetic model of force transduction.
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Cox CD, Bavi N, Martinac B. Origin of the Force: The Force-From-Lipids Principle Applied to Piezo Channels. CURRENT TOPICS IN MEMBRANES 2016; 79:59-96. [PMID: 28728824 DOI: 10.1016/bs.ctm.2016.09.001] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Piezo channels are a ubiquitously expressed, principal type of molecular force sensor in eukaryotes. They enable cells to decode a myriad of physical stimuli and are essential components of numerous mechanosensory processes. Central to their physiological role is the ability to change conformation in response to mechanical force. Here we discuss the evolutionary origin of Piezo in relation to other MS channels in addition to the force that gates Piezo channels. In particular, we discuss whether Piezo channels are inherently mechanosensitive in accordance with the force-from-lipid paradigm which has been firmly established for bacterial MS channels and two-pore domain K+ (K2P) channels. We also discuss the evidence supporting a reliance on or direct interaction with structural scaffold proteins of the cytoskeleton and extracellular matrix according to the force-from-filament principle. In doing so, we explain the false dichotomy that these distinctions represent. We also discuss the possible unifying models that shed light on channel mechanosensitivity at the molecular level.
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Affiliation(s)
- C D Cox
- Victor Chang Cardiac Research Institute, Darlinghurst, NSW, Australia; University of New South Wales, Darlinghurst, NSW, Australia
| | - N Bavi
- Victor Chang Cardiac Research Institute, Darlinghurst, NSW, Australia; University of New South Wales, Darlinghurst, NSW, Australia
| | - B Martinac
- Victor Chang Cardiac Research Institute, Darlinghurst, NSW, Australia; University of New South Wales, Darlinghurst, NSW, Australia
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Pathak D, Mallik R. Lipid - Motor Interactions: Soap Opera or Symphony? Curr Opin Cell Biol 2016; 44:79-85. [PMID: 27697416 DOI: 10.1016/j.ceb.2016.09.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Accepted: 09/08/2016] [Indexed: 11/29/2022]
Abstract
Intracellular transport of organelles can be driven by multiple motor proteins that bind to the lipid membrane of the organelle and work as a team. We review present knowledge on how lipids orchestrate the recruitment of motors to a membrane. Looking beyond recruitment, we also discuss how heterogeneity and local mechanical properties of the membrane may influence function of motor-teams. These issues gain importance because phagocytosed pathogens use lipid-centric strategies to manipulate motors and survive in host cells.
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Affiliation(s)
- Divya Pathak
- Department of Biological Sciences, Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400 005, India
| | - Roop Mallik
- Department of Biological Sciences, Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400 005, India.
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Katta S, Krieg M, Goodman MB. Feeling force: physical and physiological principles enabling sensory mechanotransduction. Annu Rev Cell Dev Biol 2016; 31:347-71. [PMID: 26566115 DOI: 10.1146/annurev-cellbio-100913-013426] [Citation(s) in RCA: 108] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Organisms as diverse as microbes, roundworms, insects, and mammals detect and respond to applied force. In animals, this ability depends on ionotropic force receptors, known as mechanoelectrical transduction (MeT) channels, that are expressed by specialized mechanoreceptor cells embedded in diverse tissues and distributed throughout the body. These cells mediate hearing, touch, and proprioception and play a crucial role in regulating organ function. Here, we attempt to integrate knowledge about the architecture of mechanoreceptor cells and their sensory organs with principles of cell mechanics, and we consider how engulfing tissues contribute to mechanical filtering. We address progress in the quest to identify the proteins that form MeT channels and to understand how these channels are gated. For clarity and convenience, we focus on sensory mechanobiology in nematodes, fruit flies, and mice. These themes are emphasized: asymmetric responses to applied forces, which may reflect anisotropy of the structure and mechanics of sensory mechanoreceptor cells, and proteins that function as MeT channels, which appear to have emerged many times through evolution.
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Affiliation(s)
- Samata Katta
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, California 94305;
| | - Michael Krieg
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, California 94305;
| | - Miriam B Goodman
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, California 94305;
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Adaptation Independent Modulation of Auditory Hair Cell Mechanotransduction Channel Open Probability Implicates a Role for the Lipid Bilayer. J Neurosci 2016; 36:2945-56. [PMID: 26961949 DOI: 10.1523/jneurosci.3011-15.2016] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The auditory system is able to detect movement down to atomic dimensions. This sensitivity comes in part from mechanisms associated with gating of hair cell mechanoelectric transduction (MET) channels. MET channels, located at the tops of stereocilia, are poised to detect tension induced by hair bundle deflection. Hair bundle deflection generates a force by pulling on tip-link proteins connecting adjacent stereocilia. The resting open probability (P(open)) of MET channels determines the linearity and sensitivity to mechanical stimulation. Classically, P(open) is regulated by a calcium-sensitive adaptation mechanism in which lowering extracellular calcium or depolarization increases P(open). Recent data demonstrated that the fast component of adaptation is independent of both calcium and voltage, thus requiring an alternative explanation for the sensitivity of P(open) to calcium and voltage. Using rat auditory hair cells, we characterize a mechanism, separate from fast adaptation, whereby divalent ions interacting with the local lipid environment modulate resting P(open). The specificity of this effect for different divalent ions suggests binding sites that are not an EF-hand or calmodulin model. GsMTx4, a lipid-mediated modifier of cationic stretch-activated channels, eliminated the voltage and divalent sensitivity with minimal effects on adaptation. We hypothesize that the dual mechanisms (lipid modulation and adaptation) extend the dynamic range of the system while maintaining adaptation kinetics at their maximal rates.
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45
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Kahraman O, Koch PD, Klug WS, Haselwandter CA. Bilayer-thickness-mediated interactions between integral membrane proteins. Phys Rev E 2016; 93:042410. [PMID: 27176332 DOI: 10.1103/physreve.93.042410] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Indexed: 12/14/2022]
Abstract
Hydrophobic thickness mismatch between integral membrane proteins and the surrounding lipid bilayer can produce lipid bilayer thickness deformations. Experiment and theory have shown that protein-induced lipid bilayer thickness deformations can yield energetically favorable bilayer-mediated interactions between integral membrane proteins, and large-scale organization of integral membrane proteins into protein clusters in cell membranes. Within the continuum elasticity theory of membranes, the energy cost of protein-induced bilayer thickness deformations can be captured by considering compression and expansion of the bilayer hydrophobic core, membrane tension, and bilayer bending, resulting in biharmonic equilibrium equations describing the shape of lipid bilayers for a given set of bilayer-protein boundary conditions. Here we develop a combined analytic and numerical methodology for the solution of the equilibrium elastic equations associated with protein-induced lipid bilayer deformations. Our methodology allows accurate prediction of thickness-mediated protein interactions for arbitrary protein symmetries at arbitrary protein separations and relative orientations. We provide exact analytic solutions for cylindrical integral membrane proteins with constant and varying hydrophobic thickness, and develop perturbative analytic solutions for noncylindrical protein shapes. We complement these analytic solutions, and assess their accuracy, by developing both finite element and finite difference numerical solution schemes. We provide error estimates of our numerical solution schemes and systematically assess their convergence properties. Taken together, the work presented here puts into place an analytic and numerical framework which allows calculation of bilayer-mediated elastic interactions between integral membrane proteins for the complicated protein shapes suggested by structural biology and at the small protein separations most relevant for the crowded membrane environments provided by living cells.
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Affiliation(s)
- Osman Kahraman
- Department of Physics & Astronomy and Molecular and Computational Biology Program, Department of Biological Sciences, University of Southern California, Los Angeles, California 90089, USA
| | - Peter D Koch
- Department of Systems Biology, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - William S Klug
- Department of Mechanical and Aerospace Engineering, University of California, Los Angeles, California 90095, USA
| | - Christoph A Haselwandter
- Department of Physics & Astronomy and Molecular and Computational Biology Program, Department of Biological Sciences, University of Southern California, Los Angeles, California 90089, USA
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Cortical actin and the plasma membrane: inextricably intertwined. Curr Opin Cell Biol 2016; 38:81-9. [PMID: 26986983 DOI: 10.1016/j.ceb.2016.02.021] [Citation(s) in RCA: 74] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Revised: 02/09/2016] [Accepted: 02/25/2016] [Indexed: 11/22/2022]
Abstract
The plasma membrane serves as a barrier, separating the cell from its external environment. Simultaneously it acts as a site for information transduction, entry of nutrients, receptor signaling, and adapts to the shape of the cell. This requires local control of organization at multiple scales in this heterogeneous fluid lipid bilayer with a plethora of proteins and a closely juxtaposed dynamic cortical cytoskeleton. New membrane models highlight the influence of the underlying cortical actin on the diffusion of membrane components. Myosin motors as well as proteins that remodel actin filaments have additionally been implicated in defining the organization of many membrane constituents. Here we provide a perspective of the intimate relationship of the membrane lipid matrix and the underlying cytoskeleton.
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Rai A, Pathak D, Thakur S, Singh S, Dubey AK, Mallik R. Dynein Clusters into Lipid Microdomains on Phagosomes to Drive Rapid Transport toward Lysosomes. Cell 2016; 164:722-34. [PMID: 26853472 PMCID: PMC4752818 DOI: 10.1016/j.cell.2015.12.054] [Citation(s) in RCA: 141] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Revised: 07/26/2015] [Accepted: 12/23/2015] [Indexed: 01/19/2023]
Abstract
Diverse cellular processes are driven by motor proteins that are recruited to and generate force on lipid membranes. Surprisingly little is known about how membranes control the force from motors and how this may impact specific cellular functions. Here, we show that dynein motors physically cluster into microdomains on the membrane of a phagosome as it matures inside cells. Such geometrical reorganization allows many dyneins within a cluster to generate cooperative force on a single microtubule. This results in rapid directed transport of the phagosome toward microtubule minus ends, likely promoting phagolysosome fusion and pathogen degradation. We show that lipophosphoglycan, the major molecule implicated in immune evasion of Leishmania donovani, inhibits phagosome motion by disrupting the clustering and therefore the cooperative force generation of dynein. These findings appear relevant to several pathogens that prevent phagosome-lysosome fusion by targeting lipid microdomains on phagosomes. Dynein clusters into lipid microdomains on the phagosome as it matures Clustering allows many dyneins to simultaneously contact a single microtubule Large cooperative forces can now be generated to transport phagosomes to lysosomes Leishmania lipophosphoglycans disrupt microdomains and inhibit this transport
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Affiliation(s)
- Ashim Rai
- Department of Biological Sciences, Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400005, India
| | - Divya Pathak
- Department of Biological Sciences, Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400005, India
| | - Shreyasi Thakur
- Department of Biological Sciences, Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400005, India
| | - Shampa Singh
- Department of Biological Sciences, Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400005, India
| | - Alok Kumar Dubey
- Department of Biological Sciences, Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400005, India
| | - Roop Mallik
- Department of Biological Sciences, Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400005, India.
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Ankyrin Repeats Convey Force to Gate the NOMPC Mechanotransduction Channel. Cell 2015; 162:1391-403. [PMID: 26359990 DOI: 10.1016/j.cell.2015.08.024] [Citation(s) in RCA: 148] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2015] [Revised: 05/26/2015] [Accepted: 07/13/2015] [Indexed: 12/11/2022]
Abstract
How metazoan mechanotransduction channels sense mechanical stimuli is not well understood. The NOMPC channel in the transient receptor potential (TRP) family, a mechanotransduction channel for Drosophila touch sensation and hearing, contains 29 Ankyrin repeats (ARs) that associate with microtubules. These ARs have been postulated to act as a tether that conveys force to the channel. Here, we report that these N-terminal ARs form a cytoplasmic domain essential for NOMPC mechanogating in vitro, mechanosensitivity of touch receptor neurons in vivo, and touch-induced behaviors of Drosophila larvae. Duplicating the ARs elongates the filaments that tether NOMPC to microtubules in mechanosensory neurons. Moreover, microtubule association is required for NOMPC mechanogating. Importantly, transferring the NOMPC ARs to mechanoinsensitive voltage-gated potassium channels confers mechanosensitivity to the chimeric channels. These experiments strongly support a tether mechanism of mechanogating for the NOMPC channel, providing insights into the basis of mechanosensitivity of mechanotransduction channels.
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49
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Pliotas C, Dahl ACE, Rasmussen T, Mahendran KR, Smith TK, Marius P, Gault J, Banda T, Rasmussen A, Miller S, Robinson CV, Bayley H, Sansom MSP, Booth IR, Naismith JH. The role of lipids in mechanosensation. Nat Struct Mol Biol 2015; 22:991-8. [PMID: 26551077 PMCID: PMC4675090 DOI: 10.1038/nsmb.3120] [Citation(s) in RCA: 129] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Accepted: 10/06/2015] [Indexed: 12/13/2022]
Abstract
The ability of proteins to sense membrane tension is pervasive in biology. A higher-resolution structure of the Escherichia coli small-conductance mechanosensitive channel MscS identifies alkyl chains inside pockets formed by the transmembrane helices (TMs). Purified MscS contains E. coli lipids, and fluorescence quenching demonstrates that phospholipid acyl chains exchange between bilayer and TM pockets. Molecular dynamics and biophysical analyses show that the volume of the pockets and thus the number of lipid acyl chains within them decreases upon channel opening. Phospholipids with one acyl chain per head group (lysolipids) displace normal phospholipids (with two acyl chains) from MscS pockets and trigger channel opening. We propose that the extent of acyl-chain interdigitation in these pockets determines the conformation of MscS. When interdigitation is perturbed by increased membrane tension or by lysolipids, the closed state becomes unstable, and the channel gates.
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Affiliation(s)
- Christos Pliotas
- Biomedical Sciences Research Complex, University of St. Andrews, St. Andrews, UK
| | | | - Tim Rasmussen
- Institute of Medical Sciences, University of Aberdeen, Aberdeen, UK
| | | | - Terry K Smith
- Biomedical Sciences Research Complex, University of St. Andrews, St. Andrews, UK
| | - Phedra Marius
- Biomedical Sciences Research Complex, University of St. Andrews, St. Andrews, UK
| | - Joseph Gault
- Department of Chemistry, University of Oxford, Oxford, UK
| | - Thandiwe Banda
- Institute of Medical Sciences, University of Aberdeen, Aberdeen, UK
| | - Akiko Rasmussen
- Institute of Medical Sciences, University of Aberdeen, Aberdeen, UK
| | - Samantha Miller
- Institute of Medical Sciences, University of Aberdeen, Aberdeen, UK
| | | | - Hagan Bayley
- Department of Chemistry, University of Oxford, Oxford, UK
| | - Mark S P Sansom
- Department of Biochemistry, University of Oxford, Oxford, UK
| | - Ian R Booth
- Institute of Medical Sciences, University of Aberdeen, Aberdeen, UK
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California, USA
| | - James H Naismith
- Biomedical Sciences Research Complex, University of St. Andrews, St. Andrews, UK
- State Key Laboratory of Biotherapy, Sichuan University, Chengdu, China
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50
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Plattner H. Signalling in ciliates: long- and short-range signals and molecular determinants for cellular dynamics. Biol Rev Camb Philos Soc 2015; 92:60-107. [PMID: 26487631 DOI: 10.1111/brv.12218] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2015] [Revised: 07/28/2015] [Accepted: 08/21/2015] [Indexed: 12/30/2022]
Abstract
In ciliates, unicellular representatives of the bikont branch of evolution, inter- and intracellular signalling pathways have been analysed mainly in Paramecium tetraurelia, Paramecium multimicronucleatum and Tetrahymena thermophila and in part also in Euplotes raikovi. Electrophysiology of ciliary activity in Paramecium spp. is a most successful example. Established signalling mechanisms include plasmalemmal ion channels, recently established intracellular Ca2+ -release channels, as well as signalling by cyclic nucleotides and Ca2+ . Ca2+ -binding proteins (calmodulin, centrin) and Ca2+ -activated enzymes (kinases, phosphatases) are involved. Many organelles are endowed with specific molecules cooperating in signalling for intracellular transport and targeted delivery. Among them are recently specified soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs), monomeric GTPases, H+ -ATPase/pump, actin, etc. Little specification is available for some key signal transducers including mechanosensitive Ca2+ -channels, exocyst complexes and Ca2+ -sensor proteins for vesicle-vesicle/membrane interactions. The existence of heterotrimeric G-proteins and of G-protein-coupled receptors is still under considerable debate. Serine/threonine kinases dominate by far over tyrosine kinases (some predicted by phosphoproteomic analyses). Besides short-range signalling, long-range signalling also exists, e.g. as firmly installed microtubular transport rails within epigenetically determined patterns, thus facilitating targeted vesicle delivery. By envisaging widely different phenomena of signalling and subcellular dynamics, it will be shown (i) that important pathways of signalling and cellular dynamics are established already in ciliates, (ii) that some mechanisms diverge from higher eukaryotes and (iii) that considerable uncertainties still exist about some essential aspects of signalling.
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Affiliation(s)
- Helmut Plattner
- Department of Biology, University of Konstanz, PO Box M625, 78457, Konstanz, Germany
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