1
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Tsai FC, Guérin G, Pernier J, Bassereau P. Actin-membrane linkers: Insights from synthetic reconstituted systems. Eur J Cell Biol 2024; 103:151402. [PMID: 38461706 DOI: 10.1016/j.ejcb.2024.151402] [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: 12/03/2023] [Revised: 02/10/2024] [Accepted: 02/28/2024] [Indexed: 03/12/2024] Open
Abstract
At the cell surface, the actin cytoskeleton and the plasma membrane interact reciprocally in a variety of processes related to the remodeling of the cell surface. The actin cytoskeleton has been known to modulate membrane organization and reshape the membrane. To this end, actin-membrane linking molecules play a major role in regulating actin assembly and spatially direct the interaction between the actin cytoskeleton and the membrane. While studies in cells have provided a wealth of knowledge on the molecular composition and interactions of the actin-membrane interface, the complex molecular interactions make it challenging to elucidate the precise actions of the actin-membrane linkers at the interface. Synthetic reconstituted systems, consisting of model membranes and purified proteins, have been a powerful approach to elucidate how actin-membrane linkers direct actin assembly to drive membrane shape changes. In this review, we will focus only on several actin-membrane linkers that have been studied by using reconstitution systems. We will discuss the design principles of these reconstitution systems and how they have contributed to the understanding of the cellular functions of actin-membrane linkers. Finally, we will provide a perspective on future research directions in understanding the intricate actin-membrane interaction.
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Affiliation(s)
- Feng-Ching Tsai
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR168, Physics of Cells and Cancer, Paris 75005, France.
| | - Gwendal Guérin
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR168, Physics of Cells and Cancer, Paris 75005, France
| | - Julien Pernier
- Tumor Cell Dynamics Unit, Inserm U1279, Gustave Roussy Institute, Université Paris-Saclay, Villejuif 94800, France
| | - Patricia Bassereau
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR168, Physics of Cells and Cancer, Paris 75005, France.
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2
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Shi B, Matsui T, Qian S, Weiss TM, Nicholl ID, Callaway DJE, Bu Z. An ensemble of cadherin-catenin-vinculin complex employs vinculin as the major F-actin binding mode. Biophys J 2023; 122:2456-2474. [PMID: 37147801 PMCID: PMC10323030 DOI: 10.1016/j.bpj.2023.04.026] [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: 10/18/2022] [Revised: 02/14/2023] [Accepted: 04/27/2023] [Indexed: 05/07/2023] Open
Abstract
The cell-cell adhesion cadherin-catenin complexes recruit vinculin to the adherens junction (AJ) to modulate the mechanical couplings between neighboring cells. However, it is unclear how vinculin influences the AJ structure and function. Here, we identified two patches of salt bridges that lock vinculin in the head-tail autoinhibited conformation and reconstituted the full-length vinculin activation mimetics bound to the cadherin-catenin complex. The cadherin-catenin-vinculin complex contains multiple disordered linkers and is highly dynamic, which poses a challenge for structural studies. We determined the ensemble conformation of this complex using small-angle x-ray and selective deuteration/contrast variation small-angle neutron scattering. In the complex, both α-catenin and vinculin adopt an ensemble of flexible conformations, but vinculin has fully open conformations with the vinculin head and actin-binding tail domains well separated from each other. F-actin binding experiments show that the cadherin-catenin-vinculin complex binds and bundles F-actin. However, when the vinculin actin-binding domain is removed from the complex, only a minor fraction of the complex binds to F-actin. The results show that the dynamic cadherin-catenin-vinculin complex employs vinculin as the primary F-actin binding mode to strengthen AJ-cytoskeleton interactions.
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Affiliation(s)
- Bright Shi
- Department of Chemistry and Biochemistry, City College of New York, City University of New York (CUNY), New York; PhD Programs in Chemistry and Biochemistry, CUNY Graduate Center, New York
| | - Tsutomu Matsui
- Stanford Synchrotron Radiation Light Source, Menlo Park, California
| | - Shuo Qian
- Second Target Station Project, Oak Ridge National Laboratory, Oak Ridge, Tennessee
| | - Thomas M Weiss
- Stanford Synchrotron Radiation Light Source, Menlo Park, California
| | - Iain D Nicholl
- Department of Biomedical Science and Physiology, Faculty of Science and Engineering, University of Wolverhampton, Wolverhampton, United Kingdom
| | - David J E Callaway
- Department of Chemistry and Biochemistry, City College of New York, City University of New York (CUNY), New York.
| | - Zimei Bu
- Department of Chemistry and Biochemistry, City College of New York, City University of New York (CUNY), New York; PhD Programs in Chemistry and Biochemistry, CUNY Graduate Center, New York.
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3
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Senju Y, Hibino E. Moesin-ezrin-radixin-like protein merlin: Its conserved and distinct functions from those of ERM proteins. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2023; 1865:184076. [PMID: 36302494 DOI: 10.1016/j.bbamem.2022.184076] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Revised: 10/13/2022] [Accepted: 10/18/2022] [Indexed: 11/06/2022]
Affiliation(s)
- Yosuke Senju
- Research Institute for Interdisciplinary Science (RIIS), Okayama University, Okayama, Japan.
| | - Emi Hibino
- Graduate School of Pharmaceutical Sciences, Nagoya University, Aichi, Japan
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4
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Korkmazhan E, Dunn AR. The membrane-actin linker ezrin acts as a sliding anchor. SCIENCE ADVANCES 2022; 8:eabo2779. [PMID: 35930643 PMCID: PMC9355349 DOI: 10.1126/sciadv.abo2779] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Protein linkages to filamentous (F)-actin provide the cell membrane with mechanical stability and support intricate membrane architectures. However, the actin cytoskeleton is highly dynamic and undergoes rapid changes in shape during cell motility and other processes. The molecular mechanisms that generate a mechanically robust yet fluid connection between the membrane and actin cytoskeleton remain poorly understood. Here, we adapted a single-molecule optical trap assay to examine how the prototypical membrane-actin linker ezrin acts to anchor F-actin to the cell membrane. We find that ezrin forms a complex that slides along F-actin over micrometer distances while resisting detachment by forces oriented perpendicular to the filament axis. The ubiquity of ezrin and analogous proteins suggests that sliding anchors such as ezrin may constitute an important but overlooked element in the construction of the actin cytoskeleton.
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Affiliation(s)
- Elgin Korkmazhan
- Department of Chemical Engineering, Stanford University, Stanford, CA 94305 USA
- Graduate Program in Biophysics, Stanford University, Stanford, CA 94305 USA
| | - Alexander R. Dunn
- Department of Chemical Engineering, Stanford University, Stanford, CA 94305 USA
- Corresponding author.
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5
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Distel JS, Flores RMO, Bienvenu A, Aguilera MO, Bonazzi M, Berón W. Ezrin and CD44 participate in the internalization process of
Coxiella burnetii
into non‐phagocytic cells. Biol Cell 2022; 114:237-253. [DOI: 10.1111/boc.202100096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Revised: 07/11/2022] [Accepted: 07/15/2022] [Indexed: 11/30/2022]
Affiliation(s)
- Jesús S. Distel
- Instituto de Histología y Embriología Facultad de Ciencias Médicas Universidad Nacional de Cuyo ‐ CONICET Mendoza 5500 Argentina
| | - Rodolfo M. Ortiz Flores
- Instituto de Histología y Embriología Facultad de Ciencias Médicas Universidad Nacional de Cuyo ‐ CONICET Mendoza 5500 Argentina
- Cátedra de Microbiología Parasitología e Inmunología Facultad de Odontología Universidad Nacional de Cuyo Mendoza Argentina
| | - Arthur Bienvenu
- Institut de Recherche en Infectiologie de Montpellier (IRIM) UMR 9004 CNRS Université de Montpellier Montpellier France
| | - Milton O. Aguilera
- Instituto de Histología y Embriología Facultad de Ciencias Médicas Universidad Nacional de Cuyo ‐ CONICET Mendoza 5500 Argentina
- Cátedra de Microbiología Parasitología e Inmunología Facultad de Odontología Universidad Nacional de Cuyo Mendoza Argentina
| | - Matteo Bonazzi
- Institut de Recherche en Infectiologie de Montpellier (IRIM) UMR 9004 CNRS Université de Montpellier Montpellier France
| | - Walter Berón
- Instituto de Histología y Embriología Facultad de Ciencias Médicas Universidad Nacional de Cuyo ‐ CONICET Mendoza 5500 Argentina
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6
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A biophysical perspective of the regulatory mechanisms of ezrin/radixin/moesin proteins. Biophys Rev 2022; 14:199-208. [PMID: 35340609 PMCID: PMC8921360 DOI: 10.1007/s12551-021-00928-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Accepted: 12/14/2021] [Indexed: 02/08/2023] Open
Abstract
Many signal transductions resulting from ligand-receptor interactions occur at the cell surface. These signaling pathways play essential roles in cell polarization, membrane morphogenesis, and the modulation of membrane tension at the cell surface. However, due to the large number of membrane-binding proteins, including actin-membrane linkers, and transmembrane proteins present at the cell surface, the molecular mechanisms underlying the regulation at the cell surface are yet unclear. Here, we describe the molecular functions of one of the key players at the cell surface, ezrin/radixin/moesin (ERM) proteins from a biophysical point of view. We focus our discussion on biophysical properties of ERM proteins revealed by using biophysical tools in live cells and in vitro reconstitution systems. We first describe the structural properties of ERM proteins and then discuss the interactions of ERM proteins with PI(4,5)P2 and the actin cytoskeleton. These properties of ERM proteins revealed by using biophysical approaches have led to a better understanding of their physiological functions in cells and tissues. Supplementary Information The online version contains supplementary material available at 10.1007/s12551-021-00928-0.
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7
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Jeong J, Shin JH, Li W, Hong JY, Lim J, Hwang JY, Chung JJ, Yan Q, Liu Y, Choi J, Wysolmerski J. MAL2 mediates the formation of stable HER2 signaling complexes within lipid raft-rich membrane protrusions in breast cancer cells. Cell Rep 2021; 37:110160. [PMID: 34965434 PMCID: PMC8762588 DOI: 10.1016/j.celrep.2021.110160] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 08/16/2021] [Accepted: 12/02/2021] [Indexed: 12/18/2022] Open
Abstract
The lipid raft-resident protein, MAL2, has been implicated as contributing to the pathogenesis of several malignancies, including breast cancer, but the underlying mechanism for its effects on tumorigenesis is unknown. Here, we show that MAL2-mediated lipid raft formation leads to HER2 plasma membrane retention and enhanced HER2 signaling in breast cancer cells. We demonstrate physical interactions between HER2 and MAL2 in lipid rafts using proximity ligation assays. Super-resolution structured illumination microscopy imaging displays the structural organization of the HER2/Ezrin/NHERF1/PMCA2 protein complex. Formation of this protein complex maintains low intracellular calcium concentrations in the vicinity of the plasma membrane. HER2/MAL2 protein interactions in lipid rafts are enhanced in trastuzumab-resistant breast cancer cells. Our findings suggest that MAL2 is crucial for lipid raft formation, HER2 signaling, and HER2 membrane stability in breast cancer cells, suggesting MAL2 as a potential therapeutic target. Jeong et al. show that the formation of MAL2-mediated lipid raft-rich membrane protrusions is crucial for HER2 signaling in breast cancer cells. MAL2 is required for the formation of HER2/Ezrin/NHERF1/PMCA2 protein complexes. Formation of these protein complexes leads to a low calcium environment in the plasma membrane
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8
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Zhu M, Cornwall-Scoones J, Wang P, Handford CE, Na J, Thomson M, Zernicka-Goetz M. Developmental clock and mechanism of de novo polarization of the mouse embryo. Science 2021; 370:370/6522/eabd2703. [PMID: 33303584 DOI: 10.1126/science.abd2703] [Citation(s) in RCA: 48] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Accepted: 10/14/2020] [Indexed: 12/31/2022]
Abstract
Embryo polarization is critical for mouse development; however, neither the regulatory clock nor the molecular trigger that it activates is known. Here, we show that the embryo polarization clock reflects the onset of zygotic genome activation, and we identify three factors required to trigger polarization. Advancing the timing of transcription factor AP-2 gamma (Tfap2c) and TEA domain transcription factor 4 (Tead4) expression in the presence of activated Ras homolog family member A (RhoA) induces precocious polarization as well as subsequent cell fate specification and morphogenesis. Tfap2c and Tead4 induce expression of actin regulators that control the recruitment of apical proteins on the membrane, whereas RhoA regulates their lateral mobility, allowing the emergence of the apical domain. Thus, Tfap2c, Tead4, and RhoA are regulators for the onset of polarization and cell fate segregation in the mouse.
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Affiliation(s)
- Meng Zhu
- Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge CB2 3DY, UK
| | - Jake Cornwall-Scoones
- Division of Biology and Biological Engineering, California Institute of Technology (Caltech), Pasadena, CA 91125, USA
| | - Peizhe Wang
- Centre for Stem Cell Biology and Regenerative Medicine, School of Medicine, Tsinghua University, Beijing 100084, China
| | - Charlotte E Handford
- Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge CB2 3DY, UK.,Centre for Trophoblast Research, University of Cambridge, Cambridge CB2 3EG, UK
| | - Jie Na
- Centre for Stem Cell Biology and Regenerative Medicine, School of Medicine, Tsinghua University, Beijing 100084, China
| | - Matt Thomson
- Division of Biology and Biological Engineering, California Institute of Technology (Caltech), Pasadena, CA 91125, USA
| | - Magdalena Zernicka-Goetz
- Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge CB2 3DY, UK. .,Division of Biology and Biological Engineering, California Institute of Technology (Caltech), Pasadena, CA 91125, USA.,Centre for Trophoblast Research, University of Cambridge, Cambridge CB2 3EG, UK
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9
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Review of PIP2 in Cellular Signaling, Functions and Diseases. Int J Mol Sci 2020; 21:ijms21218342. [PMID: 33172190 PMCID: PMC7664428 DOI: 10.3390/ijms21218342] [Citation(s) in RCA: 66] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Revised: 10/30/2020] [Accepted: 11/03/2020] [Indexed: 12/27/2022] Open
Abstract
Phosphoinositides play a crucial role in regulating many cellular functions, such as actin dynamics, signaling, intracellular trafficking, membrane dynamics, and cell-matrix adhesion. Central to this process is phosphatidylinositol bisphosphate (PIP2). The levels of PIP2 in the membrane are rapidly altered by the activity of phosphoinositide-directed kinases and phosphatases, and it binds to dozens of different intracellular proteins. Despite the vast literature dedicated to understanding the regulation of PIP2 in cells over past 30 years, much remains to be learned about its cellular functions. In this review, we focus on past and recent exciting results on different molecular mechanisms that regulate cellular functions by binding of specific proteins to PIP2 or by stabilizing phosphoinositide pools in different cellular compartments. Moreover, this review summarizes recent findings that implicate dysregulation of PIP2 in many diseases.
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10
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Abstract
Actin is a conserved cytoskeletal protein with essential functions. Here, we review the state-of-the-art reagents, tools and methods used to probe actin biology and functions in zebrafish embryo and larvae. We also discuss specific cell types and tissues where the study of actin in zebrafish has provided new insights into its functions.
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11
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Schroer CFE, Baldauf L, van Buren L, Wassenaar TA, Melo MN, Koenderink GH, Marrink SJ. Charge-dependent interactions of monomeric and filamentous actin with lipid bilayers. Proc Natl Acad Sci U S A 2020; 117:5861-5872. [PMID: 32123101 PMCID: PMC7084070 DOI: 10.1073/pnas.1914884117] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The cytoskeletal protein actin polymerizes into filaments that are essential for the mechanical stability of mammalian cells. In vitro experiments showed that direct interactions between actin filaments and lipid bilayers are possible and that the net charge of the bilayer as well as the presence of divalent ions in the buffer play an important role. In vivo, colocalization of actin filaments and divalent ions are suppressed, and cells rely on linker proteins to connect the plasma membrane to the actin network. Little is known, however, about why this is the case and what microscopic interactions are important. A deeper understanding is highly beneficial, first, to obtain understanding in the biological design of cells and, second, as a possible basis for the building of artificial cortices for the stabilization of synthetic cells. Here, we report the results of coarse-grained molecular dynamics simulations of monomeric and filamentous actin in the vicinity of differently charged lipid bilayers. We observe that charges on the lipid head groups strongly determine the ability of actin to adsorb to the bilayer. The inclusion of divalent ions leads to a reversal of the binding affinity. Our in silico results are validated experimentally by reconstitution assays with actin on lipid bilayer membranes and provide a molecular-level understanding of the actin-membrane interaction.
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Affiliation(s)
- Carsten F E Schroer
- Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, 9747 AG, Groningen, The Netherlands
- Zernike Institute for Advanced Materials, University of Groningen, 9747 AG, Groningen, The Netherlands
| | - Lucia Baldauf
- Department of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology, 2629 HZ Delft, The Netherlands
- Living Matter Department, AMOLF, 1098 XG Amsterdam, The Netherlands
| | - Lennard van Buren
- Department of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology, 2629 HZ Delft, The Netherlands
- Living Matter Department, AMOLF, 1098 XG Amsterdam, The Netherlands
| | - Tsjerk A Wassenaar
- Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, 9747 AG, Groningen, The Netherlands
- Zernike Institute for Advanced Materials, University of Groningen, 9747 AG, Groningen, The Netherlands
| | - Manuel N Melo
- Instituto de Tecnologia Química e Biológica, New University of Lisbon, 2780-157, Oeiras, Portugal
| | - Gijsje H Koenderink
- Department of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology, 2629 HZ Delft, The Netherlands;
- Living Matter Department, AMOLF, 1098 XG Amsterdam, The Netherlands
| | - Siewert J Marrink
- Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, 9747 AG, Groningen, The Netherlands;
- Zernike Institute for Advanced Materials, University of Groningen, 9747 AG, Groningen, The Netherlands
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12
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Prince DJ, Jessen JR. Dorsal convergence of gastrula cells requires Vangl2 and an adhesion protein-dependent change in protrusive activity. Development 2019; 146:dev.182188. [PMID: 31719041 DOI: 10.1242/dev.182188] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Accepted: 10/29/2019] [Indexed: 01/23/2023]
Abstract
Lateral zebrafish hypoblast cells initiate dorsal convergence near mid-gastrulation and exhibit non-polarized morphologies, limited cell-cell contact and indirect migration trajectories. By late gastrulation, mesodermal cells become packed as they engage in planar cell polarity (PCP)-dependent movement. Here, we aimed to understand this transition in cell behavior by examining the relationship between protrusion dynamics and establishment of PCP and directed migration. We found that wild-type cells undergo a reduction in bleb protrusions near late gastrulation accompanied by a VANGL planar cell polarity protein 2 (Vangl2)-regulated increase in filopodia number and polarization. Manipulation of blebs is sufficient to interfere with PCP and directed migration. We show that Vangl2, fibronectin and cadherin 2 function to suppress blebbing. Vangl2 maintains ezrin b (Ezrb) protein levels and higher Ezrb activation rescues defective mediolateral cell alignment and migration paths in vangl2 mutant embryos. Transplantation experiments show that loss of vangl2 disrupts protrusion formation cell-autonomously while fibronectin acts non-autonomously. We propose that dorsal convergence requires the coordinated action of Vangl2, Ezrb and cell-adhesion proteins to inhibit blebs and promote polarized actin-rich protrusive activity and PCP.
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Affiliation(s)
- Dianna J Prince
- Department of Biology, Middle Tennessee State University, Murfreesboro, TN 37132, USA
| | - Jason R Jessen
- Department of Biology, Middle Tennessee State University, Murfreesboro, TN 37132, USA
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13
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Bhattacharya S, Stanley CB, Heller WT, Friedman PA, Bu Z. Dynamic structure of the full-length scaffolding protein NHERF1 influences signaling complex assembly. J Biol Chem 2019; 294:11297-11310. [PMID: 31171716 PMCID: PMC6643037 DOI: 10.1074/jbc.ra119.008218] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Revised: 06/05/2019] [Indexed: 01/14/2023] Open
Abstract
The Na+/H+ exchange regulatory cofactor 1 (NHERF1) protein modulates the assembly and intracellular trafficking of several transmembrane G protein-coupled receptors (GPCRs) and ion transport proteins with the membrane-cytoskeleton adapter protein ezrin. Here, we applied solution NMR and small-angle neutron scattering (SANS) to structurally characterize full-length NHERF1 and disease-associated variants that are implicated in impaired phosphate homeostasis. Using NMR, we mapped the modular architecture of NHERF1, which is composed of two structurally-independent PDZ domains that are connected by a flexible, disordered linker. We observed that the ultra-long and disordered C-terminal tail of NHERF1 has a type 1 PDZ-binding motif that interacts weakly with the proximal, second PDZ domain to form a dynamically autoinhibited structure. Using ensemble-optimized analysis of SANS data, we extracted the molecular size distribution of structures from the extensive conformational space sampled by the flexible chain. Our results revealed that NHERF1 is a diffuse ensemble of variable PDZ domain configurations and a disordered C-terminal tail. The joint NMR/SANS data analyses of three disease variants (L110V, R153Q, and E225K) revealed significant differences in the local PDZ domain structures and in the global conformations compared with the WT protein. Furthermore, we show that the substitutions affect the affinity and kinetics of NHERF1 binding to ezrin and to a C-terminal peptide from G protein-coupled receptor kinase 6A (GRK6A). These findings provide important insight into the modulation of the intrinsic flexibility of NHERF1 by disease-associated point mutations that alter the dynamic assembly of signaling complexes.
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Affiliation(s)
| | - Christopher B Stanley
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830
| | - William T Heller
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830
| | - Peter A Friedman
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, Pennsylvania 15261
| | - Zimei Bu
- Department of Chemistry and Biochemistry, City College of New York, New York, New York 10031
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14
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Molecular Dynamics of the Association of L-Selectin and FERM Regulated by PIP2. Biophys J 2019; 114:1858-1868. [PMID: 29694864 DOI: 10.1016/j.bpj.2018.02.034] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Revised: 02/05/2018] [Accepted: 02/20/2018] [Indexed: 11/22/2022] Open
Abstract
Phosphatidylinositol 4,5-bisphosphate (PIP2) acts as a signaling lipid, mediating membrane trafficking and recruitment of proteins to membranes. A key example is the PIP2-dependent regulation of the adhesion of L-selectin to the cytoskeleton adaptors of the N-terminal subdomain of ezrin-radixin-moesin (FERM). The molecular details of the mediating behavior of multivalent anionic PIP2 lipids in this process, however, remain unclear. Here, we use coarse-grained molecular dynamics simulation to explore the mechanistic details of PIP2 in the transformation, translocation, and association of the FERM/L-selectin complex. We compare membranes of different compositions and find that anionic phospholipids are necessary for both FERM and the cytoplasmic domain of L-selectin to absorb on the membrane surface. The subsequent formation of the FERM/L-selectin complex is strongly favored by the presence of PIP2, which clusters around both proteins and triggers a conformational transition in the cytoplasmic domain of L-selectin. We are able to quantify the effect of PIP2 on the association free energy of the complex by means of a potential of mean force. We conclude that PIP2 behaves as an adhesive agent to enhance the stability of the FERM/L-selectin complex and identify key residues involved. The molecular information revealed in this study highlights the specific role of membrane lipids such as PIP2 in protein translocation and potential signaling.
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15
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Yin LM, Duan TT, Ulloa L, Yang YQ. Ezrin Orchestrates Signal Transduction in Airway Cells. Rev Physiol Biochem Pharmacol 2019; 174:1-23. [PMID: 28702704 DOI: 10.1007/112_2017_4] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Ezrin is a critical structural protein that organizes receptor complexes and orchestrates their signal transduction. In this study, we review the ezrin-meditated regulation of critical receptor complexes, including the epidermal growth factor receptor (EGFR), CD44, vascular cell adhesion molecule (VCAM), and the deleted in colorectal cancer (DCC) receptor. We also analyze the ezrin-meditated regulation of critical pathways associated with asthma, such as the RhoA, Rho-associated protein kinase (ROCK), and protein kinase A (cAMP/PKA) pathways. Mounting evidence suggests that ezrin plays a role in controlling airway cell function and potentially contributes to respiratory diseases. Ezrin can participate in asthma pathogenesis by affecting bronchial epithelium repair, T lymphocyte regulation, and the contraction of the airway smooth muscle cells. These studies provide new insights for the design of novel therapeutic strategies for asthma treatment.
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Affiliation(s)
- Lei-Miao Yin
- Laboratory of Molecular Biology, Shanghai Research Institute of Acupuncture and Meridian, Yue Yang Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, 200030, China
| | - Ting-Ting Duan
- Laboratory of Molecular Biology, Shanghai Research Institute of Acupuncture and Meridian, Yue Yang Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, 200030, China
| | - Luis Ulloa
- Laboratory of Molecular Biology, Shanghai Research Institute of Acupuncture and Meridian, Yue Yang Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, 200030, China. .,Department of Surgery, Center of Immunology and Inflammation, Rutgers-New Jersey Medical School, Rutgers University, Newark, NJ, 07101, USA.
| | - Yong-Qing Yang
- Laboratory of Molecular Biology, Shanghai Research Institute of Acupuncture and Meridian, Yue Yang Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, 200030, China.
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16
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Michie KA, Bermeister A, Robertson NO, Goodchild SC, Curmi PMG. Two Sides of the Coin: Ezrin/Radixin/Moesin and Merlin Control Membrane Structure and Contact Inhibition. Int J Mol Sci 2019; 20:ijms20081996. [PMID: 31018575 PMCID: PMC6515277 DOI: 10.3390/ijms20081996] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 04/16/2019] [Accepted: 04/19/2019] [Indexed: 12/21/2022] Open
Abstract
The merlin-ERM (ezrin, radixin, moesin) family of proteins plays a central role in linking the cellular membranes to the cortical actin cytoskeleton. Merlin regulates contact inhibition and is an integral part of cell–cell junctions, while ERM proteins, ezrin, radixin and moesin, assist in the formation and maintenance of specialized plasma membrane structures and membrane vesicle structures. These two protein families share a common evolutionary history, having arisen and separated via gene duplication near the origin of metazoa. During approximately 0.5 billion years of evolution, the merlin and ERM family proteins have maintained both sequence and structural conservation to an extraordinary level. Comparing crystal structures of merlin-ERM proteins and their complexes, a picture emerges of the merlin-ERM proteins acting as switchable interaction hubs, assembling protein complexes on cellular membranes and linking them to the actin cytoskeleton. Given the high level of structural conservation between the merlin and ERM family proteins we speculate that they may function together.
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Affiliation(s)
- Katharine A Michie
- School of Physics, University of New South Wales, Sydney 2052, Australia.
| | - Adam Bermeister
- School of Physics, University of New South Wales, Sydney 2052, Australia.
| | - Neil O Robertson
- School of Physics, University of New South Wales, Sydney 2052, Australia.
| | - Sophia C Goodchild
- Department of Molecular Sciences, Macquarie University, Sydney 2109, Australia.
| | - Paul M G Curmi
- School of Physics, University of New South Wales, Sydney 2052, Australia.
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17
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Pemberton JG, Balla T. Polyphosphoinositide-Binding Domains: Insights from Peripheral Membrane and Lipid-Transfer Proteins. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1111:77-137. [PMID: 30483964 DOI: 10.1007/5584_2018_288] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Within eukaryotic cells, biochemical reactions need to be organized on the surface of membrane compartments that use distinct lipid constituents to dynamically modulate the functions of integral proteins or influence the selective recruitment of peripheral membrane effectors. As a result of these complex interactions, a variety of human pathologies can be traced back to improper communication between proteins and membrane surfaces; either due to mutations that directly alter protein structure or as a result of changes in membrane lipid composition. Among the known structural lipids found in cellular membranes, phosphatidylinositol (PtdIns) is unique in that it also serves as the membrane-anchored precursor of low-abundance regulatory lipids, the polyphosphoinositides (PPIn), which have restricted distributions within specific subcellular compartments. The ability of PPIn lipids to function as signaling platforms relies on both non-specific electrostatic interactions and the selective stereospecific recognition of PPIn headgroups by specialized protein folds. In this chapter, we will attempt to summarize the structural diversity of modular PPIn-interacting domains that facilitate the reversible recruitment and conformational regulation of peripheral membrane proteins. Outside of protein folds capable of capturing PPIn headgroups at the membrane interface, recent studies detailing the selective binding and bilayer extraction of PPIn species by unique functional domains within specific families of lipid-transfer proteins will also be highlighted. Overall, this overview will help to outline the fundamental physiochemical mechanisms that facilitate localized interactions between PPIn lipids and the wide-variety of PPIn-binding proteins that are essential for the coordinate regulation of cellular metabolism and membrane dynamics.
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Affiliation(s)
- Joshua G Pemberton
- Section on Molecular Signal Transduction, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Tamas Balla
- Section on Molecular Signal Transduction, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA.
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18
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Tsai FC, Bertin A, Bousquet H, Manzi J, Senju Y, Tsai MC, Picas L, Miserey-Lenkei S, Lappalainen P, Lemichez E, Coudrier E, Bassereau P. Ezrin enrichment on curved membranes requires a specific conformation or interaction with a curvature-sensitive partner. eLife 2018; 7:37262. [PMID: 30234483 PMCID: PMC6167055 DOI: 10.7554/elife.37262] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Accepted: 09/14/2018] [Indexed: 01/12/2023] Open
Abstract
One challenge in cell biology is to decipher the biophysical mechanisms governing protein enrichment on curved membranes and the resulting membrane deformation. The ERM protein ezrin is abundant and associated with cellular membranes that are flat, positively or negatively curved. Using in vitro and cell biology approaches, we assess mechanisms of ezrin’s enrichment on curved membranes. We evidence that wild-type ezrin (ezrinWT) and its phosphomimetic mutant T567D (ezrinTD) do not deform membranes but self-assemble anti-parallelly, zipping adjacent membranes. EzrinTD’s specific conformation reduces intermolecular interactions, allows binding to actin filaments, which reduces membrane tethering, and promotes ezrin binding to positively-curved membranes. While neither ezrinTD nor ezrinWT senses negative curvature alone, we demonstrate that interacting with curvature-sensing I-BAR-domain proteins facilitates ezrin enrichment in negatively-curved membrane protrusions. Overall, our work demonstrates that ezrin can tether membranes, or be targeted to curved membranes, depending on conformations and interactions with actin and curvature-sensing binding partners.
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Affiliation(s)
- Feng-Ching Tsai
- Laboratoire Physico Chimie Curie, Institut Curie, PSL Research University, CNRS UMR168, Paris, France.,Sorbonne Université, Paris, France
| | - Aurelie Bertin
- Laboratoire Physico Chimie Curie, Institut Curie, PSL Research University, CNRS UMR168, Paris, France.,Sorbonne Université, Paris, France
| | - Hugo Bousquet
- Sorbonne Université, Paris, France.,Compartimentation et dynamique cellulaire, Institut Curie, PSL Research University, CNRS UMR144, Paris, France
| | - John Manzi
- Laboratoire Physico Chimie Curie, Institut Curie, PSL Research University, CNRS UMR168, Paris, France.,Sorbonne Université, Paris, France
| | - Yosuke Senju
- Program in Cell and Molecular Biology, Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Meng-Chen Tsai
- Université Côte d'Azur, CNRS, Institut de Pharmacologie Moléculaire et Cellulaire, Valbonne, France.,Département de Microbiologie, Unité des Toxines Bactériennes, Université Paris Descartes, Institut Pasteur, Paris, France
| | - Laura Picas
- Institut de Recherche en Infectiologie de Montpellier (IRIM), CNRS UMR 9004, Montpellier, France
| | - Stephanie Miserey-Lenkei
- Sorbonne Université, Paris, France.,Compartimentation et dynamique cellulaire, Institut Curie, PSL Research University, CNRS UMR144, Paris, France
| | - Pekka Lappalainen
- Program in Cell and Molecular Biology, Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Emmanuel Lemichez
- Département de Microbiologie, Unité des Toxines Bactériennes, Université Paris Descartes, Institut Pasteur, Paris, France
| | - Evelyne Coudrier
- Sorbonne Université, Paris, France.,Compartimentation et dynamique cellulaire, Institut Curie, PSL Research University, CNRS UMR144, Paris, France
| | - Patricia Bassereau
- Laboratoire Physico Chimie Curie, Institut Curie, PSL Research University, CNRS UMR168, Paris, France.,Sorbonne Université, Paris, France
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19
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Nicholl ID, Matsui T, Weiss TM, Stanley CB, Heller WT, Martel A, Farago B, Callaway DJE, Bu Z. α-Catenin Structure and Nanoscale Dynamics in Solution and in Complex with F-Actin. Biophys J 2018; 115:642-654. [PMID: 30037495 DOI: 10.1016/j.bpj.2018.07.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Revised: 06/17/2018] [Accepted: 07/05/2018] [Indexed: 12/26/2022] Open
Abstract
As a core component of the adherens junction, α-catenin stabilizes the cadherin/catenin complexes to the actin cytoskeleton for the mechanical coupling of cell-cell adhesion. α-catenin also modulates actin dynamics, cell polarity, and cell-migration functions that are independent of the adherens junction. We have determined the solution structures of the α-catenin monomer and dimer using in-line size-exclusion chromatography small-angle X-ray scattering, as well as the structure of α-catenin dimer in complex to F-actin filament using selective deuteration and contrast-matching small angle neutron scattering. We further present the first observation, to our knowledge, of the nanoscale dynamics of α-catenin by neutron spin-echo spectroscopy, which explicitly reveals the mobile regions of α-catenin that are crucial for binding to F-actin. In solution, the α-catenin monomer is more expanded than either protomer shown in the crystal structure dimer, with the vinculin-binding M fragment and the actin-binding domain being able to adopt different configurations. The α-catenin dimer in solution is also significantly more expanded than the dimer crystal structure, with fewer interdomain and intersubunit contacts than the crystal structure. When in complex to F-actin, the α-catenin dimer has an even more open and extended conformation than in solution, with the actin-binding domain further separated from the main body of the dimer. The α-catenin-assembled F-actin bundle develops into an ordered filament packing arrangement at increasing α-catenin/F-actin molar ratios. Together, the structural and dynamic studies reveal that α-catenin possesses dynamic molecular conformations that prime this protein to function as a mechanosensor protein.
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Affiliation(s)
- Iain D Nicholl
- Department of Biomedical Science and Physiology, Faculty of Science and Engineering, University of Wolverhampton, Wolverhampton, United Kingdom
| | - Tsutomu Matsui
- Stanford Synchrotron Radiation Light Source, Menlo Park, California
| | - Thomas M Weiss
- Stanford Synchrotron Radiation Light Source, Menlo Park, California
| | | | - William T Heller
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee
| | | | | | - David J E Callaway
- Department of Chemistry and Biochemistry, City College of New York, City University of New York, New York, New York.
| | - Zimei Bu
- Department of Chemistry and Biochemistry, City College of New York, City University of New York, New York, New York.
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20
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Lubart Q, Vitet H, Dalonneau F, Le Roy A, Kowalski M, Lourdin M, Ebel C, Weidenhaupt M, Picart C. Role of Phosphorylation in Moesin Interactions with PIP 2-Containing Biomimetic Membranes. Biophys J 2018; 114:98-112. [PMID: 29320700 PMCID: PMC5912500 DOI: 10.1016/j.bpj.2017.10.041] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Revised: 10/08/2017] [Accepted: 10/17/2017] [Indexed: 12/26/2022] Open
Abstract
Moesin, a protein of the ezrin, radixin, and moesin family, which links the plasma membrane to the cytoskeleton, is involved in multiple physiological and pathological processes, including viral budding and infection. Its interaction with the plasma membrane occurs via a key phosphoinositide, the phosphatidyl(4,5)inositol-bisphosphate (PIP2), and phosphorylation of residue T558, which has been shown to contribute, in cellulo, to a conformationally open protein. We study the impact of a double phosphomimetic mutation of moesin (T235D, T558D), which mimics the phosphorylation state of the protein, on protein/PIP2/microtubule interactions. Analytical ultracentrifugation in the micromolar range showed moesin in the monomer and dimer forms, with wild-type (WT) moesin containing a slightly larger fraction (∼30%) of dimers than DD moesin (10-20%). Only DD moesin was responsive to PIP2 in its micellar form. Quantitative cosedimentation assays using large unilamellar vesicles and quartz crystal microbalance on supported lipid bilayers containing PIP2 reveal a specific cooperative interaction for DD moesin with an ability to bind two PIP2 molecules simultaneously, whereas WT moesin was able to bind only one. In addition, DD moesin could subsequently interact with microtubules, whereas WT moesin was unable to do so. Altogether, our results point to an important role of these two phosphorylation sites in the opening of moesin: since DD moesin is intrinsically in a more open conformation than WT moesin, this intermolecular interaction is reinforced by its binding to PIP2. We also highlight important differences between moesin and ezrin, which appear to be finely regulated and to exhibit distinct molecular behaviors.
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Affiliation(s)
- Quentin Lubart
- CNRS UMR 5628 (LMGP), University Grenoble Alpes, CEA, CNRS, Grenoble, France; Institut National Polytechnique de Grenoble, University Grenoble Alpes, CEA, CNRS, Grenoble, France
| | - Helene Vitet
- CNRS UMR 5628 (LMGP), University Grenoble Alpes, CEA, CNRS, Grenoble, France; Institut National Polytechnique de Grenoble, University Grenoble Alpes, CEA, CNRS, Grenoble, France
| | - Fabien Dalonneau
- CNRS UMR 5628 (LMGP), University Grenoble Alpes, CEA, CNRS, Grenoble, France; Institut National Polytechnique de Grenoble, University Grenoble Alpes, CEA, CNRS, Grenoble, France
| | - Aline Le Roy
- Institut de Biologie Structurale (IBS), University Grenoble Alpes, CEA, CNRS, Grenoble, France
| | - Mathieu Kowalski
- CNRS UMR 5628 (LMGP), University Grenoble Alpes, CEA, CNRS, Grenoble, France; Institut National Polytechnique de Grenoble, University Grenoble Alpes, CEA, CNRS, Grenoble, France
| | - Morgane Lourdin
- CNRS UMR 5628 (LMGP), University Grenoble Alpes, CEA, CNRS, Grenoble, France; Institut National Polytechnique de Grenoble, University Grenoble Alpes, CEA, CNRS, Grenoble, France
| | - Christine Ebel
- Institut de Biologie Structurale (IBS), University Grenoble Alpes, CEA, CNRS, Grenoble, France
| | - Marianne Weidenhaupt
- CNRS UMR 5628 (LMGP), University Grenoble Alpes, CEA, CNRS, Grenoble, France; Institut National Polytechnique de Grenoble, University Grenoble Alpes, CEA, CNRS, Grenoble, France
| | - Catherine Picart
- CNRS UMR 5628 (LMGP), University Grenoble Alpes, CEA, CNRS, Grenoble, France; Institut National Polytechnique de Grenoble, University Grenoble Alpes, CEA, CNRS, Grenoble, France.
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21
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Shabardina V, Kramer C, Gerdes B, Braunger J, Cordes A, Schäfer J, Mey I, Grill D, Gerke V, Steinem C. Mode of Ezrin-Membrane Interaction as a Function of PIP2 Binding and Pseudophosphorylation. Biophys J 2017; 110:2710-2719. [PMID: 27332129 DOI: 10.1016/j.bpj.2016.05.009] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Revised: 04/14/2016] [Accepted: 05/05/2016] [Indexed: 12/28/2022] Open
Abstract
Ezrin, a protein of the ezrin, radixin, moesin (ERM) family, provides a regulated linkage between the plasma membrane and the cytoskeleton. The hallmark of this linkage is the activation of ezrin by phosphatidylinositol-4,5-bisphosphate (PIP2) binding and a threonine phosphorylation at position 567. To analyze the influence of these activating factors on the organization of ezrin on lipid membranes and the proposed concomitant oligomer-monomer transition, we made use of supported lipid bilayers in conjunction with atomic force microscopy and fluorescence microscopy. Bilayers doped with either PIP2 as the natural receptor lipid of ezrin or a Ni-nitrilotriacetic acid-equipped lipid to bind the proteins via their His6-tags to the lipid membrane were used to bind two different ezrin variants: ezrin wild-type and ezrin T567D mimicking the phosphorylated state. Using a combination of reflectometric interference spectroscopy, atomic force microscopy, and Förster resonance energy transfer experiments, we show that only the ezrin T567D mutant, upon binding to PIP2-containing bilayers, undergoes a remarkable conformational change, which we attribute to an opening of the conformation resulting in monomeric protein on the lipid bilayer.
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Affiliation(s)
- Victoria Shabardina
- Institute of Medical Biochemistry and Center for Molecular Biology of Inflammation, University of Münster, Münster, Germany
| | - Corinna Kramer
- Institute of Organic and Biomolecular Chemistry, University of Göttingen, Göttingen, Germany
| | - Benjamin Gerdes
- Institute of Organic and Biomolecular Chemistry, University of Göttingen, Göttingen, Germany
| | - Julia Braunger
- Institute of Organic and Biomolecular Chemistry, University of Göttingen, Göttingen, Germany
| | - Andrea Cordes
- Institute of Organic and Biomolecular Chemistry, University of Göttingen, Göttingen, Germany
| | - Jonas Schäfer
- Institute of Organic and Biomolecular Chemistry, University of Göttingen, Göttingen, Germany
| | - Ingo Mey
- Institute of Organic and Biomolecular Chemistry, University of Göttingen, Göttingen, Germany
| | - David Grill
- Institute of Medical Biochemistry and Center for Molecular Biology of Inflammation, University of Münster, Münster, Germany
| | - Volker Gerke
- Institute of Medical Biochemistry and Center for Molecular Biology of Inflammation, University of Münster, Münster, Germany.
| | - Claudia Steinem
- Institute of Organic and Biomolecular Chemistry, University of Göttingen, Göttingen, Germany; Göttingen Center for Molecular Biosciences, Göttingen, Germany.
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22
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Callaway DJE, Matsui T, Weiss T, Stingaciu LR, Stanley CB, Heller WT, Bu Z. Controllable Activation of Nanoscale Dynamics in a Disordered Protein Alters Binding Kinetics. J Mol Biol 2017; 429:987-998. [PMID: 28285124 DOI: 10.1016/j.jmb.2017.03.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Revised: 02/04/2017] [Accepted: 03/02/2017] [Indexed: 01/03/2023]
Abstract
The phosphorylation of specific residues in a flexible disordered activation loop yields precise control of signal transduction. One paradigm is the phosphorylation of S339/S340 in the intrinsically disordered tail of the multi-domain scaffolding protein NHERF1, which affects the intracellular localization and trafficking of NHERF1 assembled signaling complexes. Using neutron spin echo spectroscopy (NSE), we show salt-concentration-dependent excitation of nanoscale motion at the tip of the C-terminal tail in the phosphomimic S339D/S340D mutant. The "tip of the whip" that is unleashed is near the S339/S340 phosphorylation site and flanks the hydrophobic Ezrin-binding motif. The kinetic association rate constant of the binding of the S339D/S340D mutant to the FERM domain of Ezrin is sensitive to buffer salt concentration, correlating with the excited nanoscale dynamics. The results suggest that electrostatics modulates the activation of nanoscale dynamics of an intrinsically disordered protein, controlling the binding kinetics of signaling partners. NSE can pinpoint the nanoscale dynamics changes in a highly specific manner.
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Affiliation(s)
- David J E Callaway
- Department of Chemistry and Biochemistry, City College of New York, CUNY, New York, NY 10031, USA.
| | - Tsutomu Matsui
- Stanford Synchrotron Radiation Light Source, Menlo Park, CA 94025, USA
| | - Thomas Weiss
- Stanford Synchrotron Radiation Light Source, Menlo Park, CA 94025, USA
| | - Laura R Stingaciu
- Jülich Centre for Neutron Science JCNS, Forschungszentrum Jülich GmbH, Outstation at SNS, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Christopher B Stanley
- Biology and Soft Matter Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - William T Heller
- Biology and Soft Matter Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Zimei Bu
- Department of Chemistry and Biochemistry, City College of New York, CUNY, New York, NY 10031, USA.
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23
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Structural characterization suggests models for monomeric and dimeric forms of full-length ezrin. Biochem J 2016; 473:2763-82. [DOI: 10.1042/bcj20160541] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Accepted: 06/29/2016] [Indexed: 12/12/2022]
Abstract
Ezrin is a member of the ERM (ezrin–radixin–moesin) family of proteins that have been conserved through metazoan evolution. These proteins have dormant and active forms, where the latter links the actin cytoskeleton to membranes. ERM proteins have three domains: an N-terminal FERM [band Four-point-one (4.1) ERM] domain comprising three subdomains (F1, F2, and F3); a helical domain; and a C-terminal actin-binding domain. In the dormant form, FERM and C-terminal domains form a stable complex. We have determined crystal structures of the active FERM domain and the dormant FERM:C-terminal domain complex of human ezrin. We observe a bistable array of phenylalanine residues in the core of subdomain F3 that is mobile in the active form and locked in the dormant form. As subdomain F3 is pivotal in binding membrane proteins and phospholipids, these transitions may facilitate activation and signaling. Full-length ezrin forms stable monomers and dimers. We used small-angle X-ray scattering to determine the solution structures of these species. As expected, the monomer shows a globular domain with a protruding helical coiled coil. The dimer shows an elongated dumbbell structure that is twice as long as the monomer. By aligning ERM sequences spanning metazoan evolution, we show that the central helical region is conserved, preserving the heptad repeat. Using this, we have built a dimer model where each monomer forms half of an elongated antiparallel coiled coil with domain-swapped FERM:C-terminal domain complexes at each end. The model suggests that ERM dimers may bind to actin in a parallel fashion.
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24
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Abstract
The vertebrate small intestine requires an enormous surface area to effectively absorb nutrients from food. Morphological adaptations required to establish this extensive surface include generation of an extremely long tube and convolution of the absorptive surface of the tube into villi and microvilli. In this Review, we discuss recent findings regarding the morphogenetic and molecular processes required for intestinal tube elongation and surface convolution, examine shared and unique aspects of these processes in different species, relate these processes to known human maladies that compromise absorptive function and highlight important questions for future research.
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Affiliation(s)
- Katherine D Walton
- Cell and Developmental Biology Department, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Andrew M Freddo
- Cell and Developmental Biology Department, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Sha Wang
- Cell and Developmental Biology Department, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Deborah L Gumucio
- Cell and Developmental Biology Department, University of Michigan Medical School, Ann Arbor, MI 48109, USA
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25
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Heberle FA, Myles DAA, Katsaras J. Biomembranes research using thermal and cold neutrons. Chem Phys Lipids 2015; 192:41-50. [PMID: 26241882 DOI: 10.1016/j.chemphyslip.2015.07.020] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2015] [Revised: 07/25/2015] [Accepted: 07/27/2015] [Indexed: 01/26/2023]
Abstract
In 1932 James Chadwick discovered the neutron using a polonium source and a beryllium target (Chadwick, 1932). In a letter to Niels Bohr dated February 24, 1932, Chadwick wrote: "whatever the radiation from Be may be, it has most remarkable properties." Where it concerns hydrogen-rich biological materials, the "most remarkable" property is the neutron's differential sensitivity for hydrogen and its isotope deuterium. Such differential sensitivity is unique to neutron scattering, which unlike X-ray scattering, arises from nuclear forces. Consequently, the coherent neutron scattering length can experience a dramatic change in magnitude and phase as a result of resonance scattering, imparting sensitivity to both light and heavy atoms, and in favorable cases to their isotopic variants. This article describes recent biomembranes research using a variety of neutron scattering techniques.
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Affiliation(s)
- F A Heberle
- Biology and Soft Matter Division, Neutron Sciences Directorate, Oak Ridge, TN, 37831, United States; Joint Institute for Neutron Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, United States
| | - D A A Myles
- Biology and Soft Matter Division, Neutron Sciences Directorate, Oak Ridge, TN, 37831, United States
| | - J Katsaras
- Biology and Soft Matter Division, Neutron Sciences Directorate, Oak Ridge, TN, 37831, United States; Joint Institute for Neutron Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, United States; Department of Physics and Astronomy, University of Tennessee, Knoxville, TN, 37996, United States.
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26
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Curthoys NM, Parent M, Mlodzianoski M, Nelson AJ, Lilieholm J, Butler MB, Valles M, Hess ST. Dances with Membranes: Breakthroughs from Super-resolution Imaging. CURRENT TOPICS IN MEMBRANES 2015; 75:59-123. [PMID: 26015281 PMCID: PMC5584789 DOI: 10.1016/bs.ctm.2015.03.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Biological membrane organization mediates numerous cellular functions and has also been connected with an immense number of human diseases. However, until recently, experimental methodologies have been unable to directly visualize the nanoscale details of biological membranes, particularly in intact living cells. Numerous models explaining membrane organization have been proposed, but testing those models has required indirect methods; the desire to directly image proteins and lipids in living cell membranes is a strong motivation for the advancement of technology. The development of super-resolution microscopy has provided powerful tools for quantification of membrane organization at the level of individual proteins and lipids, and many of these tools are compatible with living cells. Previously inaccessible questions are now being addressed, and the field of membrane biology is developing rapidly. This chapter discusses how the development of super-resolution microscopy has led to fundamental advances in the field of biological membrane organization. We summarize the history and some models explaining how proteins are organized in cell membranes, and give an overview of various super-resolution techniques and methods of quantifying super-resolution data. We discuss the application of super-resolution techniques to membrane biology in general, and also with specific reference to the fields of actin and actin-binding proteins, virus infection, mitochondria, immune cell biology, and phosphoinositide signaling. Finally, we present our hopes and expectations for the future of super-resolution microscopy in the field of membrane biology.
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Affiliation(s)
- Nikki M. Curthoys
- Department of Physics and Astronomy, University of Maine, Orono, ME, USA
| | - Matthew Parent
- Department of Physics and Astronomy, University of Maine, Orono, ME, USA
| | | | - Andrew J. Nelson
- Department of Physics and Astronomy, University of Maine, Orono, ME, USA
| | - Jennifer Lilieholm
- Department of Physics and Astronomy, University of Maine, Orono, ME, USA
| | - Michael B. Butler
- Department of Physics and Astronomy, University of Maine, Orono, ME, USA
| | - Matthew Valles
- Department of Physics and Astronomy, University of Maine, Orono, ME, USA
| | - Samuel T. Hess
- Department of Physics and Astronomy, University of Maine, Orono, ME, USA
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27
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Chen X, Khajeh JA, Ju JH, Gupta YK, Stanley CB, Do C, Heller WT, Aggarwal AK, Callaway DJE, Bu Z. Phosphatidylinositol 4,5-bisphosphate clusters the cell adhesion molecule CD44 and assembles a specific CD44-Ezrin heterocomplex, as revealed by small angle neutron scattering. J Biol Chem 2015; 290:6639-52. [PMID: 25572402 PMCID: PMC4358296 DOI: 10.1074/jbc.m114.589523] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2014] [Revised: 12/30/2014] [Indexed: 01/02/2023] Open
Abstract
The cell adhesion molecule CD44 regulates diverse cellular functions, including cell-cell and cell-matrix interaction, cell motility, migration, differentiation, and growth. In cells, CD44 co-localizes with the membrane-cytoskeleton adapter protein Ezrin that links the CD44 assembled receptor signaling complexes to the cytoskeletal actin network, which organizes the spatial and temporal localization of signaling events. Here we report that the cytoplasmic tail of CD44 (CD44ct) is largely disordered. Upon binding to the signaling lipid phosphatidylinositol 4,5-bisphosphate (PIP2), CD44ct clusters into aggregates. Further, contrary to the generally accepted model, CD44ct does not bind directly to the FERM domain of Ezrin or to the full-length Ezrin but only forms a complex with FERM or with the full-length Ezrin in the presence of PIP2. Using contrast variation small angle neutron scattering, we show that PIP2 mediates the assembly of a specific heterotetramer complex of CD44ct with Ezrin. This study reveals the role of PIP2 in clustering CD44 and in assembling multimeric CD44-Ezrin complexes. We hypothesize that polyvalent electrostatic interactions are responsible for the assembly of CD44 clusters and the multimeric PIP2-CD44-Ezrin complexes.
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Affiliation(s)
- Xiaodong Chen
- From the Department of Chemistry and Biochemistry, City College of New York, New York, New York 10031, the School of Pharmacy, Jiangxi University of Traditional Chinese Medicine, Nanchang, Jiangxi 330004, China
| | - Jahan Ali Khajeh
- From the Department of Chemistry and Biochemistry, City College of New York, New York, New York 10031
| | - Jeong Ho Ju
- From the Department of Chemistry and Biochemistry, City College of New York, New York, New York 10031
| | - Yogesh K Gupta
- the Department of Structural and Chemical Biology, Icahn School of Medicine at Mount Sinai, New York, New York 10029, and
| | - Christopher B Stanley
- the Biology and Soft Matter Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831
| | - Changwoo Do
- the Biology and Soft Matter Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831
| | - William T Heller
- the Biology and Soft Matter Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831
| | - Aneel K Aggarwal
- the Department of Structural and Chemical Biology, Icahn School of Medicine at Mount Sinai, New York, New York 10029, and
| | - David J E Callaway
- From the Department of Chemistry and Biochemistry, City College of New York, New York, New York 10031
| | - Zimei Bu
- From the Department of Chemistry and Biochemistry, City College of New York, New York, New York 10031,
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Lööv C, Nadadhur AG, Hillered L, Clausen F, Erlandsson A. Extracellular ezrin: a novel biomarker for traumatic brain injury. J Neurotrauma 2014; 32:244-51. [PMID: 25087457 DOI: 10.1089/neu.2014.3517] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Traumatic brain injury (TBI) is a heterogeneous disease, and the discovery of diagnostic and prognostic TBI biomarkers is highly desirable in order to individualize patient care. We have previously published a study in which we identified possible TBI biomarkers by mass spectrometry 24 h after injury in a cell culture model. Ezrin-radixin-moesin (ERM) proteins were found abundantly in the medium after trauma, and in the present study we have identified extracellular ezrin as a possible biomarker for brain trauma by analyzing cell culture medium from injured primary neurons and glia and by measuring ezrin in cerebrospinal fluid (CSF) from both rats and humans. Our results show that extracellular ezrin concentration was substantially increased in cell culture medium after injury, but that the intracellular expression of the protein remained stable over time. Controlled cortical impact injured rats showed an increased amount of ezrin in CSF at both day 3 and day 7 after trauma. Moreover, ezrin was present in all ventricular CSF samples from seven humans with severe TBI. In contrast to intracellular ezrin, which is distinctly activated following TBI, extracellular ezrin is nonphosphorylated. This is the first report of extracellular ERM proteins in human and experimental models of TBI, providing a scientific foundation for further assessment of ezrin as a potential biomarker.
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Affiliation(s)
- Camilla Lööv
- 1 Department of Neuroscience, Division of Neurosurgery, Uppsala University Hospital , Uppsala, Sweden
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29
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Ali Khajeh J, Ju JH, Atchiba M, Allaire M, Stanley C, Heller WT, Callaway DJE, Bu Z. Molecular conformation of the full-length tumor suppressor NF2/Merlin--a small-angle neutron scattering study. J Mol Biol 2014; 426:2755-68. [PMID: 24882693 PMCID: PMC4407695 DOI: 10.1016/j.jmb.2014.05.011] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2014] [Revised: 05/11/2014] [Accepted: 05/13/2014] [Indexed: 12/26/2022]
Abstract
The tumor suppressor protein Merlin inhibits cell proliferation upon establishing cell-cell contacts. Because Merlin has high level of sequence similarity to the Ezrin-Radixin-Moesin family of proteins, the structural model of Ezrin-Radixin-Moesin protein autoinhibition and cycling between closed/resting and open/active conformational states is often employed to explain Merlin function. However, recent biochemical studies suggest alternative molecular models of Merlin function. Here, we have determined the low-resolution molecular structure and binding activity of Merlin and a Merlin(S518D) mutant that mimics the inactivating phosphorylation at S518 using small-angle neutron scattering and binding experiments. Small-angle neutron scattering shows that, in solution, both Merlin and Merlin(S518D) adopt a closed conformation, but binding experiments indicate that a significant fraction of either Merlin or Merlin(S518D) is capable of binding to the target protein NHERF1. Upon binding to the phosphatidylinositol 4,5-bisphosphate lipid, the wild-type Merlin adopts a more open conformation than in solution, but Merlin(S518D) remains in a closed conformation. This study supports a rheostat model of Merlin in NHERF1 binding and contributes to resolving a controversy about the molecular conformation and binding activity of Merlin.
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Affiliation(s)
- Jahan Ali Khajeh
- Department of Chemistry, City College of New York and CUNY Graduate Center, NY, USA
| | - Jeong Ho Ju
- Department of Chemistry, City College of New York and CUNY Graduate Center, NY, USA
| | - Moussoubaou Atchiba
- Department of Chemistry, City College of New York and CUNY Graduate Center, NY, USA
| | - Marc Allaire
- Photon Sciences Directorate, Brookhaven National Laboratory, NY, USA
| | | | - William T Heller
- Biology and Soft Matter Division, Oak Ridge National Laboratory, TN, USA
| | - David J E Callaway
- Department of Chemistry, City College of New York and CUNY Graduate Center, NY, USA
| | - Zimei Bu
- Department of Chemistry, City College of New York and CUNY Graduate Center, NY, USA.
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30
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Heller WT, Urban VS, Lynn GW, Weiss KL, O'Neill HM, Pingali SV, Qian S, Littrell KC, Melnichenko YB, Buchanan MV, Selby DL, Wignall GD, Butler PD, Myles DA. The Bio-SANS instrument at the High Flux Isotope Reactor of Oak Ridge National Laboratory. J Appl Crystallogr 2014. [DOI: 10.1107/s1600576714011285] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Small-angle neutron scattering (SANS) is a powerful tool for characterizing complex disordered materials, including biological materials. The Bio-SANS instrument of the High Flux Isotope Reactor of Oak Ridge National Laboratory (ORNL) is a high-flux low-background SANS instrument that is, uniquely among SANS instruments, dedicated to serving the needs of the structural biology and biomaterials communities as an open-access user facility. Here, the technical specifications and performance of the Bio-SANS are presented. Sample environments developed to address the needs of the user program of the instrument are also presented. Further, the isotopic labeling and sample preparation capabilities available in the Bio-Deuteration Laboratory for users of the Bio-SANS and other neutron scattering instruments at ORNL are described. Finally, a brief survey of research performed using the Bio-SANS is presented, which demonstrates the breadth of the research that the instrument's user community engages in.
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31
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Braunger JA, Brückner BR, Nehls S, Pietuch A, Gerke V, Mey I, Janshoff A, Steinem C. Phosphatidylinositol 4,5-bisphosphate alters the number of attachment sites between ezrin and actin filaments: a colloidal probe study. J Biol Chem 2014; 289:9833-43. [PMID: 24500715 DOI: 10.1074/jbc.m113.530659] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Direct linkage between the plasma membrane and the actin cytoskeleton is controlled by the protein ezrin, a member of the ezrin-radixin-moesin protein family. To function as a membrane-cytoskeleton linker, ezrin needs to be activated in a process that involves binding of ezrin to phosphatidylinositol 4,5-bisphosphate (PIP2) and phosphorylation of a conserved threonine residue. Here, we used colloidal probe microscopy to quantitatively analyze the interaction between ezrin and F-actin as a function of these activating factors. We show that the measured individual unbinding forces between ezrin and F-actin are independent of the activating parameters, in the range of approximately 50 piconewtons. However, the cumulative adhesion energy greatly increases in the presence of PIP2 demonstrating that a larger number of bonds between ezrin and F-actin has formed. In contrast, the phosphorylation state, represented by phosphor-mimetic mutants of ezrin, only plays a minor role in the activation process. These results are in line with in vivo experiments demonstrating that an increase in PIP2 concentration recruits more ezrin to the apical plasma membrane of polarized cells and significantly increases the membrane tension serving as a measure of the adhesion sites between the plasma membrane and the F-actin network.
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Affiliation(s)
- Julia A Braunger
- From the Institute of Organic and Biomolecular Chemistry, University of Göttingen, Tammannstrasse 2, 37077 Göttingen, Germany
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32
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Hendus-Altenburger R, Kragelund BB, Pedersen SF. Structural dynamics and regulation of the mammalian SLC9A family of Na⁺/H⁺ exchangers. CURRENT TOPICS IN MEMBRANES 2014; 73:69-148. [PMID: 24745981 DOI: 10.1016/b978-0-12-800223-0.00002-5] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Mammalian Na⁺/H⁺ exchangers of the SLC9A family are widely expressed and involved in numerous essential physiological processes. Their primary function is to mediate the 1:1 exchange of Na⁺ for H⁺ across the membrane in which they reside, and they play central roles in regulation of body, cellular, and organellar pH. Their function is tightly regulated through mechanisms involving interactions with multiple protein and lipid-binding partners, phosphorylations, and other posttranslational modifications. Biochemical and mutational analyses indicate that the SLC9As have a short intracellular N-terminus, 12 transmembrane (TM) helices necessary and sufficient for ion transport, and a C-terminal cytoplasmic tail region with essential regulatory roles. No high-resolution structures of the SLC9As exist; however, models based on crystal structures of the bacterial NhaAs support the 12 TM organization and suggest that TMIV and XI may form a central part of the ion-translocation pathway, whereas pH sensing may involve TMII, TMIX, and several intracellular loops. Similar to most ion transporters studied, SLC9As likely exist as coupled dimers in the membrane, and this appears to be important for the well-studied cooperativity of H⁺ binding. The aim of this work is to summarize and critically discuss the currently available evidence on the structural dynamics, regulation, and binding partner interactions of SLC9As, focusing in particular on the most widely studied isoform, SLC9A1/NHE1. Further, novel bioinformatic and structural analyses are provided that to some extent challenge the existing paradigm on how ions are transported by mammalian SLC9As.
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Affiliation(s)
- Ruth Hendus-Altenburger
- Section for Biomolecular Sciences, Department of Biology, University of Copenhagen, Copenhagen, Denmark; Section for Cell and Developmental Biology, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Birthe B Kragelund
- Section for Biomolecular Sciences, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Stine Falsig Pedersen
- Section for Cell and Developmental Biology, Department of Biology, University of Copenhagen, Copenhagen, Denmark.
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33
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Liu J, Guidry JJ, Worthylake DK. Conserved sequence repeats of IQGAP1 mediate binding to Ezrin. J Proteome Res 2013; 13:1156-66. [PMID: 24294828 DOI: 10.1021/pr400787p] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Mammalian IQGAP proteins all feature multiple ∼50 amino acid sequence repeats near their N-termini, and little is known about the function of these "Repeats". We have expressed and purified the Repeats from human IQGAP1 to identify binding partners. We used mass spectrometry to identify 42 mouse kidney proteins that associate with the IQGAP1 Repeats including the ERM proteins ezrin, radixin, and moesin. ERM proteins have an N-terminal FERM domain (4.1, ezrin, radixin, moesin) through which they bind to protein targets and phosphatidylinositol 4,5-bisphosphate (PIP2) and a C-terminal actin-binding domain and function to link the actin cytoskeleton to distinct locations on the cell cortex. Isothermal titration calorimetry (ITC) reveals that the IQGAP1 Repeats directly bind to the ezrin FERM domain, while no binding is seen for full-length "autoinhibited" ezrin or a version of full-length ezrin intended to mimic the activated protein. ITC also indicates that the ezrin FERM domain binds to the Repeats from IQGAP2 but not the Repeats from IQGAP3. We conclude that IQGAP1 and IQGAP2 are positioned at the cell cortex by ERM proteins. We propose that the IQGAP3 Repeats may likewise bind to FERM domains for signaling purposes.
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Affiliation(s)
- Jing Liu
- Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center , 1901 Perdido Street, New Orleans, Louisiana 70112, United States
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Solinet S, Mahmud K, Stewman SF, Ben El Kadhi K, Decelle B, Talje L, Ma A, Kwok BH, Carreno S. The actin-binding ERM protein Moesin binds to and stabilizes microtubules at the cell cortex. J Cell Biol 2013; 202:251-60. [PMID: 23857773 PMCID: PMC3718980 DOI: 10.1083/jcb.201304052] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2013] [Accepted: 06/07/2013] [Indexed: 01/15/2023] Open
Abstract
Ezrin, Radixin, and Moesin (ERM) proteins play important roles in many cellular processes including cell division. Recent studies have highlighted the implications of their metastatic potential in cancers. ERM's role in these processes is largely attributed to their ability to link actin filaments to the plasma membrane. In this paper, we show that the ERM protein Moesin directly binds to microtubules in vitro and stabilizes microtubules at the cell cortex in vivo. We identified two evolutionarily conserved residues in the FERM (4.1 protein and ERM) domains of ERMs that mediated the association with microtubules. This ERM-microtubule interaction was required for regulating spindle organization in metaphase and cell shape transformation after anaphase onset but was dispensable for bridging actin filaments to the metaphase cortex. These findings provide a molecular framework for understanding the complex functional interplay between the microtubule and actin cytoskeletons mediated by ERM proteins in mitosis and have broad implications in both physiological and pathological processes that require ERMs.
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Affiliation(s)
- Sara Solinet
- Cellular Mechanisms of Morphogenesis during Mitosis and Cell Motility and Chemical Biology of Cell Division, Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Québec H3C 3J7, Canada
| | - Kazi Mahmud
- Cellular Mechanisms of Morphogenesis during Mitosis and Cell Motility and Chemical Biology of Cell Division, Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Québec H3C 3J7, Canada
| | - Shannon F. Stewman
- Department of Bioengineering, The University of Illinois at Chicago, Chicago, IL 60607
| | - Khaled Ben El Kadhi
- Cellular Mechanisms of Morphogenesis during Mitosis and Cell Motility and Chemical Biology of Cell Division, Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Québec H3C 3J7, Canada
| | - Barbara Decelle
- Cellular Mechanisms of Morphogenesis during Mitosis and Cell Motility and Chemical Biology of Cell Division, Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Québec H3C 3J7, Canada
| | - Lama Talje
- Cellular Mechanisms of Morphogenesis during Mitosis and Cell Motility and Chemical Biology of Cell Division, Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Québec H3C 3J7, Canada
| | - Ao Ma
- Department of Bioengineering, The University of Illinois at Chicago, Chicago, IL 60607
| | - Benjamin H. Kwok
- Cellular Mechanisms of Morphogenesis during Mitosis and Cell Motility and Chemical Biology of Cell Division, Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Québec H3C 3J7, Canada
- Département de médecine and Département de Pathologie et de Biologie Cellulaire, Université de Montréal, Montréal, Québec H3C 3J7, Canada
| | - Sébastien Carreno
- Cellular Mechanisms of Morphogenesis during Mitosis and Cell Motility and Chemical Biology of Cell Division, Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Québec H3C 3J7, Canada
- Département de médecine and Département de Pathologie et de Biologie Cellulaire, Université de Montréal, Montréal, Québec H3C 3J7, Canada
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35
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Deng W, Cho S, Li R. FERM domain of moesin desorbs the basic-rich cytoplasmic domain of l-selectin from the anionic membrane surface. J Mol Biol 2013; 425:3549-62. [PMID: 23796515 DOI: 10.1016/j.jmb.2013.06.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2013] [Revised: 06/13/2013] [Accepted: 06/14/2013] [Indexed: 01/08/2023]
Abstract
Moesin and calmodulin (CaM) jointly associate with the cytoplasmic domain of l-selectin in the cell to modulate the function and ectodomain shedding of l-selectin. Using fluorescence spectroscopy, we have examined the association of moesin FERM domain with the recombinant transmembrane and cytoplasmic domains of l-selectin (CLS) reconstituted in model phospholipid liposomes. The dissociation constant of moesin FERM domain to CLS in the phosphatidylcholine liposome is about 300nM. In contrast to disrupting the CaM association with CLS, inclusion of anionic phosphatidylserine lipids in the phosphatidylcholine liposome increased the apparent binding affinity of moesin FERM domain for CLS. Using the environmentally sensitive fluorescent probe attached to the cytoplasmic domain of CLS and the nitroxide quencher attached to the lipid bilayer, we showed that the association of moesin FERM domain induced the desorption of the basic-rich cytoplasmic domain of CLS from the anionic membrane surface, which enabled subsequent association of CaM to the cytoplasmic domain of CLS. These results have elucidated the molecular basis for the moesin/l-selectin/CaM ternary complex and suggested an important role of phospholipids in modulating l-selectin function and shedding.
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Affiliation(s)
- Wei Deng
- Aflac Cancer and Blood Disorders Center, Department of Pediatrics, Emory University School of Medicine, 2015 Uppergate Drive NE, Room 440, Atlanta, GA 30322, USA
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Maniti O, Carvalho K, Picart C. Model membranes to shed light on the biochemical and physical properties of ezrin/radixin/moesin. Biochimie 2013; 95:3-11. [PMID: 23041444 PMCID: PMC4112940 DOI: 10.1016/j.biochi.2012.09.033] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2012] [Accepted: 09/28/2012] [Indexed: 10/27/2022]
Abstract
Ezrin, radixin and moesin (ERM) proteins are now more and more recognized to play a key role in a large number of important physiological processes such as morphogenesis, cancer metastasis and virus infection. Several recent reviews extensively discuss their biological functions [1 -4 ]. In this review, we will first remind the main features of this family of proteins, which are now known as linkers and regulators of the plasma membrane/cytoskeleton linkage. We will then briefly review their implication in pathological processes such as cancer and viral infection. In a second part, we will focus on biochemical and biophysical approaches to study ERM interaction with lipid membranes and conformational change in well-defined environments. In vitro studies using biomimetic lipid membranes, especially large unilamellar vesicles (LUVs), giant unilamellar vesicles (GUVs) and supported lipid bilayers (SLBs) and recombinant proteins help to understand the molecular mechanism of conformational activation of ERM proteins. These tools are aimed to decorticate the different steps of the interaction, to simplify the experiments performed in vivo in much more complex biological environments.
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Affiliation(s)
- Ofélia Maniti
- CNRS UMR 5628 (LMGP), Grenoble Institute of Technology and CNRS, 3 parvis Louis Néel, F-38016 Grenoble Cedex, France
- Institut de Chimie et de Biochimie Moléculaires et Supramoléculaires, UMR 5246, CNRS, Université de Lyon, Université Lyon 1, INSA-Lyon, CPE-Lyon, 43 Bd du 11 Novembre 1918, F-69622 Villeurbanne, France
| | - Kevin Carvalho
- Institut Curie, centre de recherche and CNRS UMR 168, 11 rue Pierre et Marie Curie, Paris, F-75248 cedex 5
| | - Catherine Picart
- CNRS UMR 5628 (LMGP), Grenoble Institute of Technology and CNRS, 3 parvis Louis Néel, F-38016 Grenoble Cedex, France
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Yildirim S, Castano E, Sobol M, Philimonenko VV, Dzijak R, Venit T, Hozák P. Involvement of PIP2 in RNA Polymerase I transcription. J Cell Sci 2013; 126:2730-9. [DOI: 10.1242/jcs.123661] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
RNA polymerase I (Pol I) transcription is essential for the cell cycle, growth, and overall protein synthesis in eukaryotes. We found that phosphatidylinositol 4,5-bisphosphate (PIP2) is a part of the protein complex on the active ribosomal promoter during the transcription. PIP2 makes a complex with Pol I and Pol I transcription factor UBF in the nucleolus. PIP2 depletion reduces Pol I transcription which can be rescued by the addition of exogenous PIP2. In addition, PIP2 also binds directly to the pre-rRNA processing factor, fibrillarin (Fib), and co-localizes with nascent transcripts in the nucleolus. PIP2 binding to UBF and Fib modulates their binding to DNA and RNA, respectively. In conclusion, PIP2 interacts with a subset of Pol I transcription machinery, and promotes Pol I transcription.
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38
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Expression of ezrin in subventricular zone neural stem cells and their progeny in adult and developing mice. Histochem Cell Biol 2012; 139:403-13. [DOI: 10.1007/s00418-012-1048-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/28/2012] [Indexed: 01/13/2023]
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