1
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Nyberg KG, Navales FG, Keles E, Nguyen JQ, Hertz LM, Carthew RW. Robust and heritable knockdown of gene expression using a self-cleaving ribozyme in Drosophila. Genetics 2024; 227:iyae067. [PMID: 38701221 PMCID: PMC11304983 DOI: 10.1093/genetics/iyae067] [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: 01/19/2024] [Revised: 04/11/2024] [Accepted: 04/20/2024] [Indexed: 05/05/2024] Open
Abstract
The current toolkit for genetic manipulation in the model animal Drosophila melanogaster is extensive and versatile but not without its limitations. Here, we report a powerful and heritable method to knockdown gene expression in D. melanogaster using the self-cleaving N79 hammerhead ribozyme, a modification of a naturally occurring ribozyme found in the parasite Schistosoma mansoni. A 111-bp ribozyme cassette, consisting of the N79 ribozyme surrounded by insulating spacer sequences, was inserted into 4 independent long noncoding RNA genes as well as the male-specific splice variant of doublesex using scarless CRISPR/Cas9-mediated genome editing. Ribozyme-induced RNA cleavage resulted in robust destruction of 3' fragments typically exceeding 90%. Single molecule RNA fluorescence in situ hybridization results suggest that cleavage and destruction can even occur for nascent transcribing RNAs. Knockdown was highly specific to the targeted RNA, with no adverse effects observed in neighboring genes or the other splice variants. To control for potential effects produced by the simple insertion of 111 nucleotides into genes, we tested multiple catalytically inactive ribozyme variants and found that a variant with scrambled N79 sequence best recapitulated natural RNA levels. Thus, self-cleaving ribozymes offer a novel approach for powerful gene knockdown in Drosophila, with potential applications for the study of noncoding RNAs, nuclear-localized RNAs, and specific splice variants of protein-coding genes.
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Affiliation(s)
- Kevin G Nyberg
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208, USA
| | - Fritz Gerald Navales
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208, USA
| | - Eren Keles
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208, USA
| | - Joseph Q Nguyen
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208, USA
| | - Laura M Hertz
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208, USA
| | - Richard W Carthew
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208, USA
- NSF-Simons National Institute for Theory and Mathematics in Biology, Evanston, IL 60208, USA
- NSF-Simons Center for Quantitative Biology, Evanston, IL 60208, USA
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2
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Izadi M, Wolf D, Seemann E, Ori A, Schwintzer L, Steiniger F, Kessels MM, Qualmann B. Membrane shapers from two distinct superfamilies cooperate in the development of neuronal morphology. J Cell Biol 2023; 222:e202211032. [PMID: 37318382 PMCID: PMC10274853 DOI: 10.1083/jcb.202211032] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Revised: 03/27/2023] [Accepted: 05/15/2023] [Indexed: 06/16/2023] Open
Abstract
Membrane-shaping proteins are driving forces behind establishment of proper cell morphology and function. Yet, their reported structural and in vitro properties are noticeably inconsistent with many physiological membrane topology requirements. We demonstrate that dendritic arborization of neurons is powered by physically coordinated shaping mechanisms elicited by members of two distinct classes of membrane shapers: the F-BAR protein syndapin I and the N-Ank superfamily protein ankycorbin. Strikingly, membrane-tubulating activities by syndapin I, which would be detrimental during dendritic branching, were suppressed by ankycorbin. Ankycorbin's integration into syndapin I-decorated membrane surfaces instead promoted curvatures and topologies reflecting those observed physiologically. In line with the functional importance of this mechanism, ankycorbin- and syndapin I-mediated functions in dendritic arborization mutually depend on each other and on a surprisingly specific interface mediating complex formation of the two membrane shapers. These striking results uncovered cooperative and interdependent functions of members of two fundamentally different membrane shaper superfamilies as a previously unknown, pivotal principle in neuronal shape development.
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Affiliation(s)
- Maryam Izadi
- Institute of Biochemistry I, Jena University Hospital—Friedrich Schiller University Jena, Jena, Germany
| | - David Wolf
- Institute of Biochemistry I, Jena University Hospital—Friedrich Schiller University Jena, Jena, Germany
| | - Eric Seemann
- Institute of Biochemistry I, Jena University Hospital—Friedrich Schiller University Jena, Jena, Germany
| | - Alessandro Ori
- Leibniz Institute on Aging—Fritz Lipmann Institute, Jena, Germany
| | - Lukas Schwintzer
- Institute of Biochemistry I, Jena University Hospital—Friedrich Schiller University Jena, Jena, Germany
| | - Frank Steiniger
- Electron Microscopy Center, Jena University Hospital—Friedrich Schiller University Jena, Jena, Germany
| | - Michael Manfred Kessels
- Institute of Biochemistry I, Jena University Hospital—Friedrich Schiller University Jena, Jena, Germany
| | - Britta Qualmann
- Institute of Biochemistry I, Jena University Hospital—Friedrich Schiller University Jena, Jena, Germany
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3
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De Belly H, Paluch EK, Chalut KJ. Interplay between mechanics and signalling in regulating cell fate. Nat Rev Mol Cell Biol 2022; 23:465-480. [PMID: 35365816 DOI: 10.1038/s41580-022-00472-z] [Citation(s) in RCA: 65] [Impact Index Per Article: 32.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/04/2022] [Indexed: 12/11/2022]
Abstract
Mechanical signalling affects multiple biological processes during development and in adult organisms, including cell fate transitions, cell migration, morphogenesis and immune responses. Here, we review recent insights into the mechanisms and functions of two main routes of mechanical signalling: outside-in mechanical signalling, such as mechanosensing of substrate properties or shear stresses; and mechanical signalling regulated by the physical properties of the cell surface itself. We discuss examples of how these two classes of mechanical signalling regulate stem cell function, as well as developmental processes in vivo. We also discuss how cell surface mechanics affects intracellular signalling and, in turn, how intracellular signalling controls cell surface mechanics, generating feedback into the regulation of mechanosensing. The cooperation between mechanosensing, intracellular signalling and cell surface mechanics has a profound impact on biological processes. We discuss here our understanding of how these three elements interact to regulate stem cell fate and development.
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Affiliation(s)
- Henry De Belly
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, UK
- Cardiovascular Research Institute, University of California San Francisco, San Francisco, CA, USA
- Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, CA, USA
| | - Ewa K Paluch
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, UK.
| | - Kevin J Chalut
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, UK.
- Wellcome/MRC Cambridge Stem Cell Institute, University of Cambridge, Cambridge, UK.
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4
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Francis D, Ghazanfar S, Havula E, Krycer JR, Strbenac D, Senior A, Minard AY, Geddes T, Nelson ME, Weiss F, Stöckli J, Yang JYH, James DE. Genome-wide analysis in Drosophila reveals diet-by-gene interactions and uncovers diet-responsive genes. G3-GENES GENOMES GENETICS 2021; 11:6287063. [PMID: 34568906 PMCID: PMC8496270 DOI: 10.1093/g3journal/jkab171] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/11/2021] [Accepted: 05/08/2021] [Indexed: 11/26/2022]
Abstract
Genetic and environmental factors play a major role in metabolic health. However, they do not act in isolation, as a change in an environmental factor such as diet may exert different effects based on an individual’s genotype. Here, we sought to understand how such gene–diet interactions influenced nutrient storage and utilization, a major determinant of metabolic disease. We subjected 178 inbred strains from the Drosophila genetic reference panel (DGRP) to diets varying in sugar, fat, and protein. We assessed starvation resistance, a holistic phenotype of nutrient storage and utilization that can be robustly measured. Diet influenced the starvation resistance of most strains, but the effect varied markedly between strains such that some displayed better survival on a high carbohydrate diet (HCD) compared to a high-fat diet while others had opposing responses, illustrating a considerable gene × diet interaction. This demonstrates that genetics plays a major role in diet responses. Furthermore, heritability analysis revealed that the greatest genetic variability arose from diets either high in sugar or high in protein. To uncover the genetic variants that contribute to the heterogeneity in starvation resistance, we mapped 566 diet-responsive SNPs in 293 genes, 174 of which have human orthologs. Using whole-body knockdown, we identified two genes that were required for glucose tolerance, storage, and utilization. Strikingly, flies in which the expression of one of these genes, CG4607 a putative homolog of a mammalian glucose transporter, was reduced at the whole-body level, displayed lethality on a HCD. This study provides evidence that there is a strong interplay between diet and genetics in governing survival in response to starvation, a surrogate measure of nutrient storage efficiency and obesity. It is likely that a similar principle applies to higher organisms thus supporting the case for nutrigenomics as an important health strategy.
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Affiliation(s)
- Deanne Francis
- Charles Perkins Centre, The University of Sydney, Sydney, NSW 2006, Australia.,School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW, 2006, Australia
| | - Shila Ghazanfar
- Charles Perkins Centre, The University of Sydney, Sydney, NSW 2006, Australia.,School of Mathematics and Statistics, The University of Sydney, Sydney, NSW 2006, Australia
| | - Essi Havula
- Charles Perkins Centre, The University of Sydney, Sydney, NSW 2006, Australia.,School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW, 2006, Australia
| | - James R Krycer
- Charles Perkins Centre, The University of Sydney, Sydney, NSW 2006, Australia.,School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW, 2006, Australia
| | - Dario Strbenac
- Charles Perkins Centre, The University of Sydney, Sydney, NSW 2006, Australia.,School of Mathematics and Statistics, The University of Sydney, Sydney, NSW 2006, Australia
| | - Alistair Senior
- Charles Perkins Centre, The University of Sydney, Sydney, NSW 2006, Australia.,School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW, 2006, Australia
| | - Annabel Y Minard
- Charles Perkins Centre, The University of Sydney, Sydney, NSW 2006, Australia.,School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW, 2006, Australia
| | - Thomas Geddes
- Charles Perkins Centre, The University of Sydney, Sydney, NSW 2006, Australia.,School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW, 2006, Australia
| | - Marin E Nelson
- Charles Perkins Centre, The University of Sydney, Sydney, NSW 2006, Australia.,School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW, 2006, Australia
| | - Fiona Weiss
- Charles Perkins Centre, The University of Sydney, Sydney, NSW 2006, Australia.,School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW, 2006, Australia
| | - Jacqueline Stöckli
- Charles Perkins Centre, The University of Sydney, Sydney, NSW 2006, Australia.,School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW, 2006, Australia
| | - Jean Y H Yang
- Charles Perkins Centre, The University of Sydney, Sydney, NSW 2006, Australia.,School of Mathematics and Statistics, The University of Sydney, Sydney, NSW 2006, Australia
| | - David E James
- Charles Perkins Centre, The University of Sydney, Sydney, NSW 2006, Australia.,School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW, 2006, Australia.,School of Medical Sciences, The University of Sydney, Sydney, NSW 2006, Australia
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5
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Hertenstein H, McMullen E, Weiler A, Volkenhoff A, Becker HM, Schirmeier S. Starvation-induced regulation of carbohydrate transport at the blood-brain barrier is TGF-β-signaling dependent. eLife 2021; 10:e62503. [PMID: 34032568 PMCID: PMC8149124 DOI: 10.7554/elife.62503] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Accepted: 04/13/2021] [Indexed: 12/15/2022] Open
Abstract
During hunger or malnutrition, animals prioritize alimentation of the brain over other organs to ensure its function and, thus, their survival. This protection, also-called brain sparing, is described from Drosophila to humans. However, little is known about the molecular mechanisms adapting carbohydrate transport. Here, we used Drosophila genetics to unravel the mechanisms operating at the blood-brain barrier (BBB) under nutrient restriction. During starvation, expression of the carbohydrate transporter Tret1-1 is increased to provide more efficient carbohydrate uptake. Two mechanisms are responsible for this increase. Similar to the regulation of mammalian GLUT4, Rab-dependent intracellular shuttling is needed for Tret1-1 integration into the plasma membrane; even though Tret1-1 regulation is independent of insulin signaling. In addition, starvation induces transcriptional upregulation that is controlled by TGF-β signaling. Considering TGF-β-dependent regulation of the glucose transporter GLUT1 in murine chondrocytes, our study reveals an evolutionarily conserved regulatory paradigm adapting the expression of sugar transporters at the BBB.
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Affiliation(s)
- Helen Hertenstein
- Department of Biology, Institute of Zoology, Technische Universität DresdenDresdenGermany
| | - Ellen McMullen
- Institut für Neuro- und Verhaltensbiologie, WWU MünsterMünsterGermany
| | - Astrid Weiler
- Department of Biology, Institute of Zoology, Technische Universität DresdenDresdenGermany
| | - Anne Volkenhoff
- Department of Biology, Institute of Zoology, Technische Universität DresdenDresdenGermany
| | - Holger M Becker
- Department of Biology, Institute of Zoology, Technische Universität DresdenDresdenGermany
- Division of General Zoology, Department of Biology, University of KaiserslauternKaiserslauternGermany
| | - Stefanie Schirmeier
- Department of Biology, Institute of Zoology, Technische Universität DresdenDresdenGermany
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6
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Reduced Mrp2 surface availability as PI3Kγ-mediated hepatocytic dysfunction reflecting a hallmark of cholestasis in sepsis. Sci Rep 2020; 10:13110. [PMID: 32753644 PMCID: PMC7403153 DOI: 10.1038/s41598-020-69901-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Accepted: 06/30/2020] [Indexed: 12/14/2022] Open
Abstract
Sepsis-associated liver dysfunction manifesting as cholestasis is common during multiple organ failure. Three hepatocytic dysfunctions are considered as major hallmarks of cholestasis in sepsis: impairments of microvilli covering canalicular membranes, disruptions of tight junctions sealing bile-collecting canaliculae and disruptions of Mrp2-mediated hepatobiliary transport. PI3Kγ loss-of-function was suggested as beneficial in early sepsis. Yet, the PI3Kγ-regulated cellular processes in hepatocytes remained largely unclear. We analysed all three sepsis hallmarks for responsiveness to massive PI3K/Akt signalling and PI3Kγ loss-of-function, respectively. Surprisingly, neither microvilli nor tight junctions were strongly modulated, as shown by electron microscopical studies of mouse liver samples. Instead, quantitative electron microscopy proved that solely Mrp2 surface availability, i.e. the third hallmark, responded strongly to PI3K/Akt signalling. Mrp2 plasma membrane levels were massively reduced upon PI3K/Akt signalling. Importantly, Mrp2 levels at the plasma membrane of PI3Kγ KO hepatocytes remained unaffected upon PI3K/Akt signalling stimulation. The effect explicitly relied on PI3Kγ's enzymatic ability, as shown by PI3Kγ kinase-dead mice. Keeping the surface availability of the biliary transporter Mrp2 therefore is a cell biological process that may underlie the observation that PI3Kγ loss-of-function protects from hepatic excretory dysfunction during early sepsis and Mrp2 should thus take center stage in pharmacological interventions.
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7
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The role of membrane-shaping BAR domain proteins in caveolar invagination: from mechanistic insights to pathophysiological consequences. Biochem Soc Trans 2020; 48:137-146. [DOI: 10.1042/bst20190377] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Revised: 01/28/2020] [Accepted: 02/04/2020] [Indexed: 01/25/2023]
Abstract
The formation of caveolae, bulb-shaped plasma membrane invaginations, requires the coordinated action of distinct lipid-interacting and -shaping proteins. The interdependence of caveolar structure and function has evoked substantial scientific interest given the association of human diseases with caveolar dysfunction. Model systems deficient of core components of caveolae, caveolins or cavins, did not allow for an explicit attribution of observed functional defects to the requirement of caveolar invagination as they lack both invaginated caveolae and caveolin proteins. Knockdown studies in cultured cells and recent knockout studies in mice identified an additional family of membrane-shaping proteins crucial for caveolar formation, syndapins (PACSINs) — BAR domain superfamily proteins characterized by crescent-shaped membrane binding interfaces recognizing and inducing distinct curved membrane topologies. Importantly, syndapin loss-of-function resulted exclusively in impairment of caveolar invagination without a reduction in caveolin or cavin at the plasma membrane, thereby allowing the specific role of the caveolar invagination to be unveiled. Muscle cells of syndapin III KO mice showed severe reductions of caveolae reminiscent of human caveolinopathies and were more vulnerable to membrane damage upon changes in membrane tensions. Consistent with the lack of syndapin III-dependent invaginated caveolae providing mechanoprotection by releasing membrane reservoirs through caveolar flattening, physical exercise of syndapin III KO mice resulted in pathological defects reminiscent of the clinical symptoms of human myopathies associated with caveolin 3 mutation suggesting that the ability of muscular caveolae to respond to mechanical forces is a key physiological process.
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8
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Seemann E, Kessels MM, Qualmann B. Freeze-Fracture Replica Immunolabeling of Cryopreserved Membrane Compartments, Cultured Cells and Tissues. Methods Mol Biol 2020; 2169:11-25. [PMID: 32548815 DOI: 10.1007/978-1-0716-0732-9_2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Membrane topology information and views of membrane-embedded protein complexes promote our understanding of membrane organization and cell biological function involving membrane compartments. Freeze-fracturing of biological membranes offers both stunning views onto integral membrane proteins and perpendicular views over wide areas of the membrane at electron microscopical resolution. This information is directly assessable for 3D analyses and quantitative analyses of the distribution of components within the membrane if it were possible to specifically detect the components of interest in the membranes. Freeze-fracture replica immunolabeling (FRIL) achieves just that. In addition, FRIL preserves antigens in their genuine cellular context free of artifacts of chemical fixation, as FRIL uses chemically unfixed cellular samples that are rapidly cryofixed. In principle, the method is not limited to integral proteins spanning the membrane. Theoretically, all membrane components should be addressable as long as they are antigenic, embedded into at least one membrane leaflet, and accessible for immunolabeling from either the intracellular or the extracellular side. Consistently, integral proteins spanning both leaflets and only partially inserted membrane proteins have been successfully identified and studied for their molecular organization and distribution in the membrane and/or in relationship to specialized membrane domains. Here we describe the freeze-fracturing of both cultured cells and tissues and the sample preparations that allowed for a successful immunogold-labeling of caveolin1 and caveolin3 or even for double-immunolabelings of caveolins with members of the syndapin family of membrane-associating and -shaping BAR domain proteins as well as with cavin 1. For this purpose samples are cryopreserved, fractured, and replicated. We also describe how the obtained stabilized membrane fractures are then cleaned to remove all loosely attached material and immunogold labeled to finally be viewed by transmission electron microscopy.
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Affiliation(s)
- Eric Seemann
- Institute for Biochemistry I, Jena University Hospital - Friedrich Schiller University Jena, Jena, Germany
| | - Michael M Kessels
- Institute for Biochemistry I, Jena University Hospital - Friedrich Schiller University Jena, Jena, Germany.
| | - Britta Qualmann
- Institute for Biochemistry I, Jena University Hospital - Friedrich Schiller University Jena, Jena, Germany.
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9
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Wolf D, Hofbrucker-MacKenzie SA, Izadi M, Seemann E, Steiniger F, Schwintzer L, Koch D, Kessels MM, Qualmann B. Ankyrin repeat-containing N-Ank proteins shape cellular membranes. Nat Cell Biol 2019; 21:1191-1205. [PMID: 31548610 DOI: 10.1038/s41556-019-0381-7] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Accepted: 07/25/2019] [Indexed: 01/02/2023]
Abstract
Cells of multicellular organisms need to adopt specific morphologies. However, the molecular mechanisms bringing about membrane topology changes are far from understood-mainly because knowledge of membrane-shaping proteins that can promote local membrane curvatures is still limited. Our analyses unveiled that several members of a large, previously unrecognised protein family, which we termed N-Ank proteins, use a combination of their ankyrin repeat array and an amino (N)-terminal amphipathic helix to bind and shape membranes. Consistently, functional analyses revealed that the N-Ank protein ankycorbin (NORPEG/RAI14), which was exemplarily characterised further, plays an important, ankyrin repeat-based and N-terminal amphipathic helix-dependent role in early morphogenesis of neurons. This function furthermore required coiled coil-mediated self-assembly and manifested as ankycorbin nanodomains marked by protrusive membrane topologies. In summary, here, we unveil a class of powerful membrane shapers and thereby assign mechanistic and cell biological functions to the N-Ank protein superfamily.
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Affiliation(s)
- David Wolf
- Institute of Biochemistry I, Jena University Hospital, Friedrich Schiller University Jena, Jena, Germany
| | | | - Maryam Izadi
- Institute of Biochemistry I, Jena University Hospital, Friedrich Schiller University Jena, Jena, Germany
| | - Eric Seemann
- Institute of Biochemistry I, Jena University Hospital, Friedrich Schiller University Jena, Jena, Germany
| | - Frank Steiniger
- Electron Microscopy Centre, Jena University Hospital, Friedrich Schiller University Jena, Jena, Germany
| | - Lukas Schwintzer
- Institute of Biochemistry I, Jena University Hospital, Friedrich Schiller University Jena, Jena, Germany
| | - Dennis Koch
- Institute of Biochemistry I, Jena University Hospital, Friedrich Schiller University Jena, Jena, Germany
| | - Michael Manfred Kessels
- Institute of Biochemistry I, Jena University Hospital, Friedrich Schiller University Jena, Jena, Germany.
| | - Britta Qualmann
- Institute of Biochemistry I, Jena University Hospital, Friedrich Schiller University Jena, Jena, Germany.
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10
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Malinova TS, Huveneers S. Sensing of Cytoskeletal Forces by Asymmetric Adherens Junctions. Trends Cell Biol 2018; 28:328-341. [DOI: 10.1016/j.tcb.2017.11.002] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Revised: 11/09/2017] [Accepted: 11/10/2017] [Indexed: 12/13/2022]
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11
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Seemann E, Sun M, Krueger S, Tröger J, Hou W, Haag N, Schüler S, Westermann M, Huebner CA, Romeike B, Kessels MM, Qualmann B. Deciphering caveolar functions by syndapin III KO-mediated impairment of caveolar invagination. eLife 2017; 6. [PMID: 29202928 PMCID: PMC5716666 DOI: 10.7554/elife.29854] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Accepted: 11/14/2017] [Indexed: 12/11/2022] Open
Abstract
Several human diseases are associated with a lack of caveolae. Yet, the functions of caveolae and the molecular mechanisms critical for shaping them still are debated. We show that muscle cells of syndapin III KO mice show severe reductions of caveolae reminiscent of human caveolinopathies. Yet, different from other mouse models, the levels of the plasma membrane-associated caveolar coat proteins caveolin3 and cavin1 were both not reduced upon syndapin III KO. This allowed for dissecting bona fide caveolar functions from those supported by mere caveolin presence and also demonstrated that neither caveolin3 nor caveolin3 and cavin1 are sufficient to form caveolae. The membrane-shaping protein syndapin III is crucial for caveolar invagination and KO rendered the cells sensitive to membrane tensions. Consistent with this physiological role of caveolae in counterpoising membrane tensions, syndapin III KO skeletal muscles showed pathological parameters upon physical exercise that are also found in CAVEOLIN3 mutation-associated muscle diseases.
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Affiliation(s)
- Eric Seemann
- Institute for Biochemistry I, Jena University Hospital - Friedrich Schiller University Jena, Jena, Germany
| | - Minxuan Sun
- Institute for Biochemistry I, Jena University Hospital - Friedrich Schiller University Jena, Jena, Germany
| | - Sarah Krueger
- Institute for Biochemistry I, Jena University Hospital - Friedrich Schiller University Jena, Jena, Germany
| | - Jessica Tröger
- Institute for Biochemistry I, Jena University Hospital - Friedrich Schiller University Jena, Jena, Germany
| | - Wenya Hou
- Institute for Biochemistry I, Jena University Hospital - Friedrich Schiller University Jena, Jena, Germany
| | - Natja Haag
- Institute for Biochemistry I, Jena University Hospital - Friedrich Schiller University Jena, Jena, Germany
| | - Susann Schüler
- Institute for Biochemistry I, Jena University Hospital - Friedrich Schiller University Jena, Jena, Germany
| | - Martin Westermann
- Electron Microscopy Center, Jena University Hospital - Friedrich Schiller University Jena, Jena, Germany
| | - Christian A Huebner
- Institute for Human Genetics, Jena University Hospital - Friedrich Schiller University Jena, Jena, Germany
| | - Bernd Romeike
- Institute of Pathology, Division of Neuropathology, Jena University Hospital - Friedrich Schiller University Jena, Jena, Germany
| | - Michael M Kessels
- Institute for Biochemistry I, Jena University Hospital - Friedrich Schiller University Jena, Jena, Germany
| | - Britta Qualmann
- Institute for Biochemistry I, Jena University Hospital - Friedrich Schiller University Jena, Jena, Germany
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12
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Brüser L, Bogdan S. Adherens Junctions on the Move-Membrane Trafficking of E-Cadherin. Cold Spring Harb Perspect Biol 2017; 9:cshperspect.a029140. [PMID: 28096264 DOI: 10.1101/cshperspect.a029140] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Cadherin-based adherens junctions are conserved structures that mediate epithelial cell-cell adhesion in invertebrates and vertebrates. Despite their pivotal function in epithelial integrity, adherens junctions show a remarkable plasticity that is a prerequisite for tissue architecture and morphogenesis. Epithelial cadherin (E-cadherin) is continuously turned over and undergoes cycles of endocytosis, sorting and recycling back to the plasma membrane. Mammalian cell culture and genetically tractable model systems such as Drosophila have revealed conserved, but also distinct, mechanisms in the regulation of E-cadherin membrane trafficking. Here, we discuss our current knowledge about molecules and mechanisms controlling endocytosis, sorting and recycling of E-cadherin during junctional remodeling.
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Affiliation(s)
- Lena Brüser
- Institut für Neurobiologie, Universität Münster, Badestraße 9, 48149 Münster, Germany
| | - Sven Bogdan
- Institut für Neurobiologie, Universität Münster, Badestraße 9, 48149 Münster, Germany.,Institut für Physiologie und Pathophysiologie, Abteilung Molekulare Zellphysiologie, Phillips-Universität Marburg, Emil-Mannkopff-Straße 2, 35037 Marburg, Germany
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13
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Salzer U, Kostan J, Djinović-Carugo K. Deciphering the BAR code of membrane modulators. Cell Mol Life Sci 2017; 74:2413-2438. [PMID: 28243699 PMCID: PMC5487894 DOI: 10.1007/s00018-017-2478-0] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Revised: 01/25/2017] [Accepted: 01/27/2017] [Indexed: 01/06/2023]
Abstract
The BAR domain is the eponymous domain of the “BAR-domain protein superfamily”, a large and diverse set of mostly multi-domain proteins that play eminent roles at the membrane cytoskeleton interface. BAR domain homodimers are the functional units that peripherally associate with lipid membranes and are involved in membrane sculpting activities. Differences in their intrinsic curvatures and lipid-binding properties account for a large variety in membrane modulating properties. Membrane activities of BAR domains are further modified and regulated by intramolecular or inter-subunit domains, by intermolecular protein interactions, and by posttranslational modifications. Rather than providing detailed cell biological information on single members of this superfamily, this review focuses on biochemical, biophysical, and structural aspects and on recent findings that paradigmatically promote our understanding of processes driven and modulated by BAR domains.
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Affiliation(s)
- Ulrich Salzer
- Max F. Perutz Laboratories, Department of Medical Biochemistry, Medical University of Vienna, Dr. Bohr-Gasse 9, 1030, Vienna, Austria
| | - Julius Kostan
- Max F. Perutz Laboratories, Department of Structural and Computational Biology, University of Vienna, Campus Vienna Biocenter 5, 1030, Vienna, Austria
| | - Kristina Djinović-Carugo
- Max F. Perutz Laboratories, Department of Structural and Computational Biology, University of Vienna, Campus Vienna Biocenter 5, 1030, Vienna, Austria.
- Department of Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Večna pot 119, 1000, Ljubljana, Slovenia.
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14
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Abstract
BAR domain proteins can regulate ‘membrane reservoirs’ that provide surface area and buffer membrane tension. Syndapin is an F-BAR and SH3 domain containing protein involved in cytoskeletal remodelling and endocytosis. The Syndapin F-BAR domain is uniquely versatile compared to others in the family and can bend phospholipid membranes into tubules of various diameters and directly bind actin. The Syndapin SH3 domain can also interact with actin remodelling proteins and modulate cytoskeletal contractility. Pseudocleavage furrow extension in the syncytial division cycles of Drosophila embryos requires the homeostatic control of conserved processes that control plasma membrane tension and actin contractility. We find that Syndapin plays an important role in promoting pseudocleavage furrow extension. We propose a model involving roles for Syndapin in membrane dynamics and direct or indirect effect on the cytoskeleton to explain how it affects pseudocleavage furrow growth, independent of its role in endocytosis.
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Affiliation(s)
- Aparna Sherlekar
- Biology, Indian Institute of Science Education and Research, Pune, India
| | - Richa Rikhy
- Biology, Indian Institute of Science Education and Research, Pune, India
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15
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Dorland YL, Malinova TS, van Stalborch AMD, Grieve AG, van Geemen D, Jansen NS, de Kreuk BJ, Nawaz K, Kole J, Geerts D, Musters RJP, de Rooij J, Hordijk PL, Huveneers S. The F-BAR protein pacsin2 inhibits asymmetric VE-cadherin internalization from tensile adherens junctions. Nat Commun 2016; 7:12210. [PMID: 27417273 PMCID: PMC4947187 DOI: 10.1038/ncomms12210] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Accepted: 06/10/2016] [Indexed: 12/14/2022] Open
Abstract
Vascular homoeostasis, development and disease critically depend on the regulation of endothelial cell-cell junctions. Here we uncover a new role for the F-BAR protein pacsin2 in the control of VE-cadherin-based endothelial adhesion. Pacsin2 concentrates at focal adherens junctions (FAJs) that are experiencing unbalanced actomyosin-based pulling. FAJs move in response to differences in local cytoskeletal geometry and pacsin2 is recruited consistently to the trailing end of fast-moving FAJs via a mechanism that requires an intact F-BAR domain. Photoconversion, photobleaching, immunofluorescence and super-resolution microscopy reveal polarized dynamics, and organization of junctional proteins between the front of FAJs and their trailing ends. Interestingly, pacsin2 recruitment inhibits internalization of the VE-cadherin complex from FAJ trailing ends and is important for endothelial monolayer integrity. Together, these findings reveal a novel junction protective mechanism during polarized trafficking of VE-cadherin, which supports barrier maintenance within dynamic endothelial tissue.
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Affiliation(s)
- Yvonne L Dorland
- Department of Molecular Cell Biology, Sanquin Research and Landsteiner Laboratory, University of Amsterdam, Amsterdam 1066 CX, The Netherlands
| | - Tsveta S Malinova
- Department of Medical Biochemistry, Academic Medical Center, University of Amsterdam, Amsterdam 1105 AZ, The Netherlands
| | - Anne-Marieke D van Stalborch
- Department of Molecular Cell Biology, Sanquin Research and Landsteiner Laboratory, University of Amsterdam, Amsterdam 1066 CX, The Netherlands
| | - Adam G Grieve
- Hubrecht Institute and University Medical Center Utrecht, Utrecht 3584 CT, The Netherlands
| | - Daphne van Geemen
- Department of Molecular Cell Biology, Sanquin Research and Landsteiner Laboratory, University of Amsterdam, Amsterdam 1066 CX, The Netherlands
| | - Nicolette S Jansen
- Department of Molecular Cell Biology, Sanquin Research and Landsteiner Laboratory, University of Amsterdam, Amsterdam 1066 CX, The Netherlands
| | - Bart-Jan de Kreuk
- Department of Medicine, University of California, San Diego, California 92093, USA
| | - Kalim Nawaz
- Department of Molecular Cell Biology, Sanquin Research and Landsteiner Laboratory, University of Amsterdam, Amsterdam 1066 CX, The Netherlands
| | - Jeroen Kole
- Department of Physiology, VU University Medical Center, Amsterdam 1081 HV, The Netherlands
| | - Dirk Geerts
- Department of Pediatric Oncology/Hematology, Erasmus University Medical Center, Rotterdam 3015 GE, The Netherlands
| | - René J P Musters
- Department of Physiology, VU University Medical Center, Amsterdam 1081 HV, The Netherlands
| | - Johan de Rooij
- Department of Molecular Cancer Research, Center for Molecular Medicine, University Medical Center Utrecht, Utrecht 3584 CG, The Netherlands
| | - Peter L Hordijk
- Department of Physiology, VU University Medical Center, Amsterdam 1081 HV, The Netherlands
| | - Stephan Huveneers
- Department of Molecular Cell Biology, Sanquin Research and Landsteiner Laboratory, University of Amsterdam, Amsterdam 1066 CX, The Netherlands.,Department of Medical Biochemistry, Academic Medical Center, University of Amsterdam, Amsterdam 1105 AZ, The Netherlands
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16
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Brinkmann K, Winterhoff M, Önel SF, Schultz J, Faix J, Bogdan S. WHAMY is a novel actin polymerase promoting myoblast fusion, macrophage cell motility and sensory organ development in Drosophila. J Cell Sci 2015; 129:604-20. [PMID: 26675239 DOI: 10.1242/jcs.179325] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Accepted: 12/09/2015] [Indexed: 01/06/2023] Open
Abstract
Wiskott-Aldrich syndrome proteins (WASPs) are nucleation-promoting factors (NPF) that differentially control the Arp2/3 complex. In Drosophila, three different family members, SCAR (also known as WAVE), WASP and WASH (also known as CG13176), have been analyzed so far. Here, we characterized WHAMY, the fourth Drosophila WASP family member. whamy originated from a wasp gene duplication and underwent a sub-neofunctionalization. Unlike WASP, we found that WHAMY specifically interacted with activated Rac1 through its two CRIB domains, which were sufficient for targeting WHAMY to lamellipodial and filopodial tips. Biochemical analyses showed that WHAMY promoted exceptionally fast actin filament elongation, although it did not activate the Arp2/3 complex. Loss- and gain-of-function studies revealed an important function of WHAMY in membrane protrusions and cell migration in macrophages. Genetic data further implied synergistic functions between WHAMY and WASP during morphogenesis. Double mutants were late-embryonic lethal and showed severe defects in myoblast fusion. Trans-heterozygous mutant animals showed strongly increased defects in sensory cell fate specification. Thus, WHAMY is a novel actin polymerase with an initial partitioning of ancestral WASP functions in development and subsequent acquisition of a new function in cell motility during evolution.
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Affiliation(s)
- Klaus Brinkmann
- Institut für Neurobiologie, Universität Münster, Badestr. 9, Münster 48149, Germany
| | - Moritz Winterhoff
- Institut für Biophysikalische Chemie, Medizinische Hochschule Hannover, Carl-Neuberg Strasse 1, Hannover 30625, Germany
| | - Susanne-Filiz Önel
- Fachbereich Biologie, Entwicklungsbiologie, Philipps-Universität Marburg, Karl-von-Frisch Str. 8, Marburg 35043, Germany
| | - Jörg Schultz
- Center for Computational and Theoretical Biology, Campus Nord and Bioinformatik, Biozentrum, Am Hubland, Universität Würzburg, Würzburg 97074, Germany
| | - Jan Faix
- Institut für Biophysikalische Chemie, Medizinische Hochschule Hannover, Carl-Neuberg Strasse 1, Hannover 30625, Germany
| | - Sven Bogdan
- Institut für Neurobiologie, Universität Münster, Badestr. 9, Münster 48149, Germany
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17
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Seebach J, Taha AA, Lenk J, Lindemann N, Jiang X, Brinkmann K, Bogdan S, Schnittler HJ. The CellBorderTracker, a novel tool to quantitatively analyze spatiotemporal endothelial junction dynamics at the subcellular level. Histochem Cell Biol 2015; 144:517-32. [PMID: 26275669 DOI: 10.1007/s00418-015-1357-8] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/11/2015] [Indexed: 11/28/2022]
Abstract
Endothelial junctions are dynamic structures organized by multi-protein complexes that control monolayer integrity, homeostasis, inflammation, cell migration and angiogenesis. Newly developed methods for both the genetic manipulation of endothelium and microscopy permit time-lapse recordings of fluorescent proteins over long periods of time. Quantitative data analyses require automated methods. We developed a software package, the CellBorderTracker, allowing quantitative analysis of fluorescent-tagged cell junction protein dynamics in time-lapse sequences. The CellBorderTracker consists of the CellBorderExtractor that segments cells and identifies cell boundaries and mapping tools for data extraction. The tool is illustrated by analyzing fluorescent-tagged VE-cadherin the backbone of adherence junctions in endothelium. VE-cadherin displays high dynamics that is forced by junction-associated intermittent lamellipodia (JAIL) that are actin driven and WASP/ARP2/3 complex controlled. The manual segmentation and the automatic one agree to 90 %, a value that indicates high reliability. Based on segmentations, different maps were generated allowing more detailed data extraction. This includes the quantification of protein distribution pattern, the generation of regions of interest, junction displacements, cell shape changes, migration velocities and the visualization of junction dynamics over many hours. Furthermore, we demonstrate an advanced kymograph, the J-kymograph that steadily follows irregular cell junction dynamics in time-lapse sequences for individual junctions at the subcellular level. By using the CellBorderTracker, we demonstrate that VE-cadherin dynamics is quickly arrested upon thrombin stimulation, a phenomenon that was largely due to transient inhibition of JAIL and display a very heterogeneous subcellular and divers VE-cadherin dynamics during intercellular gap formation and resealing.
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Affiliation(s)
- Jochen Seebach
- Institute of Anatomy and Vascular Biology, Westfälische Wilhelms-Universität Münster, Vesaliusweg 2-4, 48149, Münster, Germany.
| | - Abdallah Abu Taha
- Institute of Anatomy and Vascular Biology, Westfälische Wilhelms-Universität Münster, Vesaliusweg 2-4, 48149, Münster, Germany
| | - Janine Lenk
- Faculty of Medicine Carl Gustav Carus, Fetscherstrasse 74, 01307, Dresden, Germany
| | - Nico Lindemann
- Institute of Anatomy and Vascular Biology, Westfälische Wilhelms-Universität Münster, Vesaliusweg 2-4, 48149, Münster, Germany
| | - Xiaoyi Jiang
- Department of Computer Science, Westfälische Wilhelms-Universität Münster, Münster, Germany
| | - Klaus Brinkmann
- Institute for Neurobiology, Westfälische Wilhelms-Universität Münster, Münster, Germany
| | - Sven Bogdan
- Institute for Neurobiology, Westfälische Wilhelms-Universität Münster, Münster, Germany
| | - Hans-Joachim Schnittler
- Institute of Anatomy and Vascular Biology, Westfälische Wilhelms-Universität Münster, Vesaliusweg 2-4, 48149, Münster, Germany.
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18
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Kovacevic I, Müller M, Kojonazarov B, Ehrke A, Randriamboavonjy V, Kohlstedt K, Hindemith T, Schermuly RT, Fleming I, Hoffmeister M, Oess S. The F-BAR Protein NOSTRIN Dictates the Localization of the Muscarinic M3 Receptor and Regulates Cardiovascular Function. Circ Res 2015; 117:460-9. [DOI: 10.1161/circresaha.115.306187] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2015] [Accepted: 07/10/2015] [Indexed: 12/16/2022]
Abstract
Rationale:
Endothelial dysfunction is an early event in cardiovascular disease and characterized by reduced production of nitric oxide (NO). The F-BAR protein NO synthase traffic inducer (NOSTRIN) is an interaction partner of endothelial NO synthase and modulates its subcellular localization, but the role of NOSTRIN in pathophysiology in vivo is unclear.
Objective:
We analyzed the consequences of deleting the
NOSTRIN
gene in endothelial cells on NO production and cardiovascular function in vivo using NOSTRIN knockout mice.
Methods and Results:
The levels of NO and cGMP were significantly reduced in mice with endothelial cell–specific deletion of the
NOSTRIN
gene resulting in diastolic heart dysfunction. In addition, systemic blood pressure was increased, and myograph measurements indicated an impaired acetylcholine-induced relaxation of isolated aortic rings and resistance arteries. We found that the muscarinic acetylcholine receptor subtype M3 (M3R) interacted directly with NOSTRIN, and the latter was necessary for correct localization of the M3R at the plasma membrane in murine aorta. In the absence of NOSTRIN, the acetylcholine-induced increase in intracellular Ca
2+
in primary endothelial cells was abolished. Moreover, the activating phosphorylation and Golgi translocation of endothelial NO synthase in response to the M3R agonist carbachol were diminished.
Conclusions:
NOSTRIN is crucial for the localization and function of the M3R and NO production. The loss of NOSTRIN in mice leads to endothelial dysfunction, increased blood pressure, and diastolic heart failure.
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Affiliation(s)
- Igor Kovacevic
- From the Institute for Biochemistry II, Goethe-University Frankfurt Medical School, Frankfurt/Main, Germany (I.K., M.M., A.E., T.H., M.H., S.O.); Universities of Giessen and Marburg Lung Center, Member of the German Center for Lung Research, Giessen, Germany (B.K., R.T.S.); and Institute for Vascular Signalling, Goethe-University Frankfurt, Frankfurt/Main, Germany (V.R., K.K., I.F.)
| | - Miriam Müller
- From the Institute for Biochemistry II, Goethe-University Frankfurt Medical School, Frankfurt/Main, Germany (I.K., M.M., A.E., T.H., M.H., S.O.); Universities of Giessen and Marburg Lung Center, Member of the German Center for Lung Research, Giessen, Germany (B.K., R.T.S.); and Institute for Vascular Signalling, Goethe-University Frankfurt, Frankfurt/Main, Germany (V.R., K.K., I.F.)
| | - Baktybek Kojonazarov
- From the Institute for Biochemistry II, Goethe-University Frankfurt Medical School, Frankfurt/Main, Germany (I.K., M.M., A.E., T.H., M.H., S.O.); Universities of Giessen and Marburg Lung Center, Member of the German Center for Lung Research, Giessen, Germany (B.K., R.T.S.); and Institute for Vascular Signalling, Goethe-University Frankfurt, Frankfurt/Main, Germany (V.R., K.K., I.F.)
| | - Alexander Ehrke
- From the Institute for Biochemistry II, Goethe-University Frankfurt Medical School, Frankfurt/Main, Germany (I.K., M.M., A.E., T.H., M.H., S.O.); Universities of Giessen and Marburg Lung Center, Member of the German Center for Lung Research, Giessen, Germany (B.K., R.T.S.); and Institute for Vascular Signalling, Goethe-University Frankfurt, Frankfurt/Main, Germany (V.R., K.K., I.F.)
| | - Voahanginirina Randriamboavonjy
- From the Institute for Biochemistry II, Goethe-University Frankfurt Medical School, Frankfurt/Main, Germany (I.K., M.M., A.E., T.H., M.H., S.O.); Universities of Giessen and Marburg Lung Center, Member of the German Center for Lung Research, Giessen, Germany (B.K., R.T.S.); and Institute for Vascular Signalling, Goethe-University Frankfurt, Frankfurt/Main, Germany (V.R., K.K., I.F.)
| | - Karin Kohlstedt
- From the Institute for Biochemistry II, Goethe-University Frankfurt Medical School, Frankfurt/Main, Germany (I.K., M.M., A.E., T.H., M.H., S.O.); Universities of Giessen and Marburg Lung Center, Member of the German Center for Lung Research, Giessen, Germany (B.K., R.T.S.); and Institute for Vascular Signalling, Goethe-University Frankfurt, Frankfurt/Main, Germany (V.R., K.K., I.F.)
| | - Tanja Hindemith
- From the Institute for Biochemistry II, Goethe-University Frankfurt Medical School, Frankfurt/Main, Germany (I.K., M.M., A.E., T.H., M.H., S.O.); Universities of Giessen and Marburg Lung Center, Member of the German Center for Lung Research, Giessen, Germany (B.K., R.T.S.); and Institute for Vascular Signalling, Goethe-University Frankfurt, Frankfurt/Main, Germany (V.R., K.K., I.F.)
| | - Ralph Theo Schermuly
- From the Institute for Biochemistry II, Goethe-University Frankfurt Medical School, Frankfurt/Main, Germany (I.K., M.M., A.E., T.H., M.H., S.O.); Universities of Giessen and Marburg Lung Center, Member of the German Center for Lung Research, Giessen, Germany (B.K., R.T.S.); and Institute for Vascular Signalling, Goethe-University Frankfurt, Frankfurt/Main, Germany (V.R., K.K., I.F.)
| | - Ingrid Fleming
- From the Institute for Biochemistry II, Goethe-University Frankfurt Medical School, Frankfurt/Main, Germany (I.K., M.M., A.E., T.H., M.H., S.O.); Universities of Giessen and Marburg Lung Center, Member of the German Center for Lung Research, Giessen, Germany (B.K., R.T.S.); and Institute for Vascular Signalling, Goethe-University Frankfurt, Frankfurt/Main, Germany (V.R., K.K., I.F.)
| | - Meike Hoffmeister
- From the Institute for Biochemistry II, Goethe-University Frankfurt Medical School, Frankfurt/Main, Germany (I.K., M.M., A.E., T.H., M.H., S.O.); Universities of Giessen and Marburg Lung Center, Member of the German Center for Lung Research, Giessen, Germany (B.K., R.T.S.); and Institute for Vascular Signalling, Goethe-University Frankfurt, Frankfurt/Main, Germany (V.R., K.K., I.F.)
| | - Stefanie Oess
- From the Institute for Biochemistry II, Goethe-University Frankfurt Medical School, Frankfurt/Main, Germany (I.K., M.M., A.E., T.H., M.H., S.O.); Universities of Giessen and Marburg Lung Center, Member of the German Center for Lung Research, Giessen, Germany (B.K., R.T.S.); and Institute for Vascular Signalling, Goethe-University Frankfurt, Frankfurt/Main, Germany (V.R., K.K., I.F.)
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19
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Van Itallie CM, Tietgens AJ, Krystofiak E, Kachar B, Anderson JM. A complex of ZO-1 and the BAR-domain protein TOCA-1 regulates actin assembly at the tight junction. Mol Biol Cell 2015; 26:2769-87. [PMID: 26063734 PMCID: PMC4571337 DOI: 10.1091/mbc.e15-04-0232] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Accepted: 06/05/2015] [Indexed: 02/06/2023] Open
Abstract
An alternative splice in TOCA-1 targets it to tight junctions. KO of TOCA-1 results in increased flux and decreased tight junction membrane dynamics. Ultrastructural analysis shows actin accumulation at the adherens junction. Identification of the ZO-1/TOCA-1 complex provides insights into tight junction barrier dependence on the dynamic nature of cell–cell contacts and junctional actin. Assembly and sealing of the tight junction barrier are critically dependent on the perijunctional actin cytoskeleton, yet little is known about physical and functional links between barrier-forming proteins and actin. Here we identify a novel functional complex of the junction scaffolding protein ZO-1 and the F-BAR–domain protein TOCA-1. Using MDCK epithelial cells, we show that an alternative splice of TOCA-1 adds a PDZ-binding motif, which binds ZO-1, targeting TOCA-1 to barrier contacts. This isoform of TOCA-1 recruits the actin nucleation–promoting factor N-WASP to tight junctions. CRISPR-Cas9–mediated knockout of TOCA-1 results in increased paracellular flux and delayed recovery in a calcium switch assay. Knockout of TOCA-1 does not alter FRAP kinetics of GFP ZO-1 or occludin, but longer term (12 h) time-lapse microscopy reveals strikingly decreased tight junction membrane contact dynamics in knockout cells compared with controls. Reexpression of TOCA-1 with, but not without, the PDZ-binding motif rescues both altered flux and membrane contact dynamics. Ultrastructural analysis shows actin accumulation at the adherens junction in TOCA-1–knockout cells but unaltered freeze-fracture fibril morphology. Identification of the ZO-1/TOCA-1 complex provides novel insights into the underappreciated dependence of the barrier on the dynamic nature of cell-to-cell contacts and perijunctional actin.
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Affiliation(s)
- Christina M Van Itallie
- Laboratory of Tight Junction Structure and Function, National Heart, Lung, and Blood Institute, Bethesda, MD 20892
| | - Amber Jean Tietgens
- Laboratory of Tight Junction Structure and Function, National Heart, Lung, and Blood Institute, Bethesda, MD 20892
| | - Evan Krystofiak
- Laboratory of Cell Structure and Dynamics, National Institute of Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD 20892
| | - Bechara Kachar
- Laboratory of Cell Structure and Dynamics, National Institute of Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD 20892
| | - James M Anderson
- Laboratory of Tight Junction Structure and Function, National Heart, Lung, and Blood Institute, Bethesda, MD 20892
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