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Liang Z, Dondorp DC, Chatzigeorgiou M. The ion channel Anoctamin 10/TMEM16K coordinates organ morphogenesis across scales in the urochordate notochord. PLoS Biol 2024; 22:e3002762. [PMID: 39173068 PMCID: PMC11341064 DOI: 10.1371/journal.pbio.3002762] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2023] [Accepted: 07/20/2024] [Indexed: 08/24/2024] Open
Abstract
During embryonic development, tissues and organs are gradually shaped into their functional morphologies through a series of spatiotemporally tightly orchestrated cell behaviors. A highly conserved organ shape across metazoans is the epithelial tube. Tube morphogenesis is a complex multistep process of carefully choreographed cell behaviors such as convergent extension, cell elongation, and lumen formation. The identity of the signaling molecules that coordinate these intricate morphogenetic steps remains elusive. The notochord is an essential tubular organ present in the embryonic midline region of all members of the chordate phylum. Here, using genome editing, pharmacology and quantitative imaging in the early chordate Ciona intestinalis we show that Ano10/Tmem16k, a member of the evolutionarily ancient family of transmembrane proteins called Anoctamin/TMEM16 is essential for convergent extension, lumen expansion, and connection during notochord morphogenesis. We find that Ano10/Tmem16k works in concert with the plasma membrane (PM) localized Na+/Ca2+ exchanger (NCX) and the endoplasmic reticulum (ER) residing SERCA, RyR, and IP3R proteins to establish developmental stage specific Ca2+ signaling molecular modules that regulate notochord morphogenesis and Ca2+ dynamics. In addition, we find that the highly conserved Ca2+ sensors calmodulin (CaM) and Ca2+/calmodulin-dependent protein kinase (CaMK) show an Ano10/Tmem16k-dependent subcellular localization. Their pharmacological inhibition leads to convergent extension, tubulogenesis defects, and deranged Ca2+ dynamics, suggesting that Ano10/Tmem16k is involved in both the "encoding" and "decoding" of developmental Ca2+ signals. Furthermore, Ano10/Tmem16k mediates cytoskeletal reorganization during notochord morphogenesis, likely by altering the localization of 2 important cytoskeletal regulators, the small GTPase Ras homolog family member A (RhoA) and the actin binding protein Cofilin. Finally, we use electrophysiological recordings and a scramblase assay in tissue culture to demonstrate that Ano10/Tmem16k likely acts as an ion channel but not as a phospholipid scramblase. Our results establish Ano10/Tmem16k as a novel player in the prevertebrate molecular toolkit that controls organ morphogenesis across scales.
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Affiliation(s)
- Zonglai Liang
- Michael Sars Centre, University of Bergen, Bergen, Norway
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2
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Kofman K, Levin M. Bioelectric pharmacology of cancer: A systematic review of ion channel drugs affecting the cancer phenotype. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2024; 191:25-39. [PMID: 38971325 DOI: 10.1016/j.pbiomolbio.2024.07.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2024] [Revised: 05/21/2024] [Accepted: 07/04/2024] [Indexed: 07/08/2024]
Abstract
Cancer is a pernicious and pressing medical problem; moreover, it is a failure of multicellular morphogenesis that sheds much light on evolutionary developmental biology. Numerous classes of pharmacological agents have been considered as cancer therapeutics and evaluated as potential carcinogenic agents; however, these are spread throughout the primary literature. Here, we briefly review recent work on ion channel drugs as promising anti-cancer treatments and present a systematic review of the known cancer-relevant effects of 109 drugs targeting ion channels. The roles of ion channels in cancer are consistent with the importance of bioelectrical parameters in cell regulation and with the functions of bioelectric signaling in morphogenetic signals that act as cancer suppressors. We find that compounds that are well-known for having targets in the nervous system, such as voltage-gated ion channels, ligand-gated ion channels, proton pumps, and gap junctions are especially relevant to cancer. Our review suggests further opportunities for the repurposing of numerous promising candidates in the field of cancer electroceuticals.
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Affiliation(s)
- Karina Kofman
- Faculty of Dentistry, University of Toronto, Toronto, Canada
| | - Michael Levin
- Allen Discovery Center at Tufts University, USA; Wyss Institute for Biologically Inspired Engineering at Harvard University, USA.
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3
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Li Y, Piermarini PM. Effects of dietary calcium (Ca 2+) and blood feeding on the immunochemical expression of the plasma membrane Ca 2+-ATPase (PMCA) in Malpighian tubules of adult female mosquitoes (Aedes aegypti). Comp Biochem Physiol A Mol Integr Physiol 2024; 292:111623. [PMID: 38458419 DOI: 10.1016/j.cbpa.2024.111623] [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: 01/05/2024] [Revised: 03/01/2024] [Accepted: 03/05/2024] [Indexed: 03/10/2024]
Abstract
Insect Malpighian tubules contribute to Ca2+ homeostasis via Ca2+ storage in intracellular compartments, Ca2+ secretion into the tubule lumen, and Ca2+ reabsorption into the hemolymph. A plasma membrane Ca2+-ATPase (PMCA) is hypothesized to be a Ca2+-transporter involved in renal Ca2+ transport of insects, however few studies have investigated its immunochemical expression in Malpighian tubules. Here we characterized the abundance and localization of PMCA-like immunoreactivity in Malpighian tubules of adult female mosquitoes Aedes aegypti using an antibody against Drosophila melanogaster PMCA. Western blotting revealed expression of a relatively abundant 109 kDa isoform and a relatively sparse 115 kDa isoform. Feeding mosquitoes 10% sucrose with 50 mM CaCl2 for 7 days did not affect PMCA immunoreactivity. However, at 24, 48, and 96 h post-blood feeding (PBF), the relative abundance of the 109 kDa isoform decreased while that of the 115 kDa isoform increased. Immunolabeling of Malpighian tubules revealed PMCA-like immunoreactivity in both principal and stellate cells; principal cell labeling was intracellular, whereas stellate cell labeling was along the basal membrane. Blood feeding enhanced immunolabeling of PMCA in stellate cells but weakened that in principal cells. Moreover, a unique apicolateral pattern of PMCA-like immunolabeling occurred in principal cells of the proximal segment at 24 h PBF, suggesting potential trafficking to septate junctions. Our results suggest PMCA isoforms are differentially expressed and localized in mosquito Malpighian tubules where they contribute to redistributing tubule Ca2+ during blood meal processing.
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Affiliation(s)
- Yuan Li
- Department of Entomology, The Ohio State University, Wooster, OH 44691, United States of America
| | - Peter M Piermarini
- Department of Entomology, The Ohio State University, Wooster, OH 44691, United States of America.
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4
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Herbertz M, Lohr J, Lohr C, Dobler S. Knockdown of Na,K-ATPase β-subunits in Oncopeltus fasciatus induces molting problems and alterations in tracheal morphology. INSECT SCIENCE 2023; 30:375-397. [PMID: 36102008 DOI: 10.1111/1744-7917.13117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Revised: 08/17/2022] [Accepted: 08/22/2022] [Indexed: 06/15/2023]
Abstract
The ubiquitously expressed transmembrane enzyme Na,K-ATPase (NKA) is vital in maintaining functionality of cells. The association of α- and β-subunits is believed to be essential for forming a functional enzyme. In the large milkweed bug Oncopeltus fasciatus four α1-paralogs and four β-subunits exist that can associate into NKA complexes. This diversity raises the question of possible tissue-specific distribution and function. While the α1-subunits are known to modulate cardenolide-resistance and ion-transport efficiency, the functional importance of the β-subunits needed further investigation. We here characterize all four different β-subunits at the cellular, tissue, and whole organismal scales. A knockdown of different β-subunits heavily interferes with molting success resulting in strongly hampered phenotypes. The failure of ecdysis might be related to disrupted septate junction (SJ) formation, also reflected in β2-suppression-induced alteration in tracheal morphology. Our data further suggest the existence of isolated β-subunits forming homomeric or β-heteromeric complexes. This possible standalone and structure-specific distribution of the β-subunits predicts further, yet unknown pump-independent functions. The different effects caused by β knockdowns highlight the importance of the various β-subunits to fulfill tissue-specific requirements.
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Affiliation(s)
- Marlena Herbertz
- Division of Molecular Evolutionary Biology, Department of Biology, Institute of Cell and Systems Biology of Animals, Universität Hamburg, Hamburg, 20146, Germany
| | - Jennifer Lohr
- Division of Molecular Evolutionary Biology, Department of Biology, Institute of Cell and Systems Biology of Animals, Universität Hamburg, Hamburg, 20146, Germany
| | - Christian Lohr
- Division of Neurophysiology, Department of Biology, Institute of Cell and Systems Biology of Animals, Universität Hamburg, Hamburg, 20146, Germany
| | - Susanne Dobler
- Division of Molecular Evolutionary Biology, Department of Biology, Institute of Cell and Systems Biology of Animals, Universität Hamburg, Hamburg, 20146, Germany
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5
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Jonusaite S, Oulhen N, Izumi Y, Furuse M, Yamamoto T, Sakamoto N, Wessel G, Heyland A. Identification of the genes encoding candidate septate junction components expressed during early development of the sea urchin, Strongylocentrotus purpuratus, and evidence of a role for Mesh in the formation of the gut barrier. Dev Biol 2023; 495:21-34. [PMID: 36587799 DOI: 10.1016/j.ydbio.2022.12.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 12/20/2022] [Accepted: 12/22/2022] [Indexed: 12/30/2022]
Abstract
Septate junctions (SJs) evolved as cell-cell junctions that regulate the paracellular barrier and integrity of epithelia in invertebrates. Multiple morphological variants of SJs exist specific to different epithelia and/or phyla but the biological significance of varied SJ morphology is unclear because the knowledge of the SJ associated proteins and their functions in non-insect invertebrates remains largely unknown. Here we report cell-specific expression of nine candidate SJ genes in the early life stages of the sea urchin Strongylocentrotus purpuratus. By use of in situ RNA hybridization and single cell RNA-seq we found that the expression of selected genes encoding putatively SJ associated transmembrane and cytoplasmic scaffold molecules was dynamically regulated during epithelial development in the embryos and larvae with different epithelia expressing different cohorts of SJ genes. We focused a functional analysis on SpMesh, a homolog of the Drosophila smooth SJ component Mesh, which was highly enriched in the endodermal epithelium of the mid- and hindgut. Functional perturbation of SpMesh by both CRISPR/Cas9 mutagenesis and vivo morpholino-mediated knockdown shows that loss of SpMesh does not disrupt the formation of the gut epithelium during gastrulation. However, loss of SpMesh resulted in a severely reduced gut-paracellular barrier as quantitated by increased permeability to 3-5 kDa FITC-dextran. Together, these studies provide a first look at the molecular SJ physiology during the development of a marine organism and suggest a shared role for Mesh-homologous proteins in forming an intestinal barrier in invertebrates. Results have implications for consideration of the traits underlying species-specific sensitivity of marine larvae to climate driven ocean change.
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Affiliation(s)
- Sima Jonusaite
- Department of Integrative Biology, University of Guelph, Guelph, ON N1G 2W1, Canada.
| | - Nathalie Oulhen
- Department of Molecular and Cell Biology and Biochemistry, Brown University, Providence, RI, 02912, United States
| | - Yasushi Izumi
- Division of Cell Structure, National Institute for Physiological Sciences, Okazaki, 444-8787, Japan
| | - Mikio Furuse
- Division of Cell Structure, National Institute for Physiological Sciences, Okazaki, 444-8787, Japan; Nagoya University Graduate School of Medicine, Aichi, 464-8601, Japan
| | - Takashi Yamamoto
- Division of Integrated Sciences for Life, Graduate School of Integrated Sciences for Life, Hiroshima University, Hiroshima, 739-8526, Japan
| | - Naoaki Sakamoto
- Division of Integrated Sciences for Life, Graduate School of Integrated Sciences for Life, Hiroshima University, Hiroshima, 739-8526, Japan
| | - Gary Wessel
- Department of Molecular and Cell Biology and Biochemistry, Brown University, Providence, RI, 02912, United States
| | - Andreas Heyland
- Department of Integrative Biology, University of Guelph, Guelph, ON N1G 2W1, Canada
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Levic DS, Bagnat M. Polarized transport of membrane and secreted proteins during lumen morphogenesis. Semin Cell Dev Biol 2023; 133:65-73. [PMID: 35307284 PMCID: PMC9481742 DOI: 10.1016/j.semcdb.2022.03.016] [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: 12/03/2021] [Revised: 03/09/2022] [Accepted: 03/12/2022] [Indexed: 10/18/2022]
Abstract
A ubiquitous feature of animal development is the formation of fluid-filled cavities or lumina, which transport gases and fluids across tissues and organs. Among different species, lumina vary drastically in size, scale, and complexity. However, all lumen formation processes share key morphogenetic principles that underly their development. Fundamentally, a lumen simply consists of epithelial cells that encapsulate a continuous internal space, and a common way of building a lumen is via opening and enlarging by filling it with fluid and/or macromolecules. Here, we discuss how polarized targeting of membrane and secreted proteins regulates lumen formation, mainly focusing on ion transporters in vertebrate model systems. We also discuss mechanistic differences observed among invertebrates and vertebrates and describe how the unique properties of the Na+/K+-ATPase and junctional proteins can promote polarization of immature epithelia to build lumina de novo in developing organs.
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Affiliation(s)
- Daniel S Levic
- Department of Cell Biology, Duke University, Durham, NC 27710, USA.
| | - Michel Bagnat
- Department of Cell Biology, Duke University, Durham, NC 27710, USA.
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7
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Martinez NP, Pinch M, Kandel Y, Hansen IA. Knockdown of the Sodium/Potassium ATPase Subunit Beta 2 Reduces Egg Production in the Dengue Vector, Aedes aegypti. INSECTS 2023; 14:50. [PMID: 36661978 PMCID: PMC9862990 DOI: 10.3390/insects14010050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Revised: 12/26/2022] [Accepted: 12/31/2022] [Indexed: 06/17/2023]
Abstract
The Na+/K+ ATPase (NKA) is present in the cellular membrane of most eukaryotic cells. It utilizes energy released by ATP hydrolysis to pump sodium ions out of the cell and potassium ions into the cell, which establishes and controls ion gradients. Functional NKA pumps consist of three subunits, alpha, beta, and FXYD. The alpha subunit serves as the catalytic subunit while the beta and FXYD subunits regulate the proper folding and localization, and ion affinity of the alpha subunit, respectively. Here we demonstrate that knockdown of NKA beta subunit 2 mRNA (nkaβ2) reduces fecundity in female Ae. aegypti. We determined the expression pattern of nkaβ2 in several adult mosquito organs using qRT-PCR. We performed RNAi-mediated knockdown of nkaβ2 and assayed for lethality, and effects on female fecundity. Tissue expression levels of nkaβ2 mRNA were highest in the ovaries with the fat body, midgut and thorax having similar expression levels, while Malpighian tubules had significantly lower expression. Survival curves recorded post dsRNA injection showed a non-significant decrease in survival of nkaβ2 dsRNA-injected mosquitoes compared to GFP dsRNA-injected mosquitoes. We observed a significant reduction in the number of eggs laid by nkaβ2 dsRNA-injected mosquitoes compared to control mosquitoes. These results, coupled with the tissue expression profile of nkaβ2, indicate that this subunit plays a role in normal female Ae. aegypti fecundity. Additional research needs to be conducted to determine the exact role played by NKAβ2 in mosquito post-blood meal nutrient sensing, transport, yolk precursor protein (YPP) synthesis and yolk deposition.
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Affiliation(s)
- Nathan P. Martinez
- Department of Biology, New Mexico State University, Las Cruces, NM 88003, USA
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8
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Herbertz M, Harder S, Schlüter H, Lohr C, Dobler S. Na,K-ATPase α1 and β-subunits show distinct localizations in the nervous tissue of the large milkweed bug. Cell Tissue Res 2022; 388:503-519. [PMID: 35332371 PMCID: PMC9110512 DOI: 10.1007/s00441-022-03580-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Accepted: 01/11/2022] [Indexed: 11/28/2022]
Abstract
The Na,K-ATPase (NKA) is an essential ion transporter and signaling molecule in all animal tissues and believed to consist at least one α and one ß-subunit to form a functional enzyme. In the large milkweed bug, Oncopeltus fasciatus, adaptation to dietary cardiac glycosides (CGs), which can fatally block the NKA, has resulted in gene duplications leading to four α1-subunits. These differ in sensitivity to CGs, but resistance trades off against ion pumping activity, thus influencing the α1-subunits’ suitability for specific tissues. Besides, O. fasciatus possesses four different ß-subunits that can alter the NKA's kinetics and should play an essential role in the formation of cellular junctions. Proteomic analyses revealed the distribution and composition of α1/ß-complexes in the nervous tissue of O. fasciatus. The highly CG-resistant, but less active α1B and the highly active, but less resistant α1C predominated in the nervous tissue and co-occurred with ß2 and ß3, partly forming larger complexes than just heterodimers. Immunohistochemical analyses provided a fine scale resolution of the subunits’ distribution in different morphological structures of the nervous tissue. This may suggest that α1 as well as ß-subunits occur in isolation without the other subunit, which contradicts the present understanding that the two types of subunits have to associate to form functional complexes. An isolated occurrence was especially prominent for ß3 and βx, the enigmatic fourth and N-terminally largely truncated ß-subunit. We hypothesize that dimerization of these ß-subunits plays a role in cell–cell contacts.
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Affiliation(s)
- Marlena Herbertz
- Institute of Cell and Systems Biology of Animals, Molecular Evolutionary Biology, Universität Hamburg, 20146, Hamburg, Germany.
| | - Sönke Harder
- Institute of Clinical Chemistry and Laboratory Medicine, University Medical Center Hamburg-Eppendorf, 20246, Hamburg, Germany
| | - Hartmut Schlüter
- Institute of Clinical Chemistry and Laboratory Medicine, University Medical Center Hamburg-Eppendorf, 20246, Hamburg, Germany
| | - Christian Lohr
- Institute of Cell and Systems Biology of Animals, Neurophysiology, Universität Hamburg, 20146, Hamburg, Germany
| | - Susanne Dobler
- Institute of Cell and Systems Biology of Animals, Molecular Evolutionary Biology, Universität Hamburg, 20146, Hamburg, Germany
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9
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Huang M, Wang X, Banerjee M, Mukherji ST, Kutz LC, Zhao A, Sepanski M, Fan CM, Zhu GZ, Tian J, Wang DZ, Zhu H, Xie ZJ, Pierre SV, Cai L. Regulation of Myogenesis by a Na/K-ATPase α1 Caveolin-Binding Motif. Stem Cells 2022; 40:133-148. [PMID: 35257186 PMCID: PMC8943859 DOI: 10.1093/stmcls/sxab012] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Accepted: 09/25/2021] [Indexed: 01/12/2024]
Abstract
The N-terminal caveolin-binding motif (CBM) in Na/K-ATPase (NKA) α1 subunit is essential for cell signaling and somitogenesis in animals. To further investigate the molecular mechanism, we have generated CBM mutant human-induced pluripotent stem cells (iPSCs) through CRISPR/Cas9 genome editing and examined their ability to differentiate into skeletal muscle (Skm) cells. Compared with the parental wild-type human iPSCs, the CBM mutant cells lost their ability of Skm differentiation, which was evidenced by the absence of spontaneous cell contraction, marker gene expression, and subcellular myofiber banding structures in the final differentiated induced Skm cells. Another NKA functional mutant, A420P, which lacks NKA/Src signaling function, did not produce a similar defect. Indeed, A420P mutant iPSCs retained intact pluripotency and ability of Skm differentiation. Mechanistically, the myogenic transcription factor MYOD was greatly suppressed by the CBM mutation. Overexpression of a mouse Myod cDNA through lentiviral delivery restored the CBM mutant cells' ability to differentiate into Skm. Upstream of MYOD, Wnt signaling was demonstrated from the TOPFlash assay to have a similar inhibition. This effect on Wnt activity was further confirmed functionally by defective induction of the presomitic mesoderm marker genes BRACHYURY (T) and MESOGENIN1 (MSGN1) by Wnt3a ligand or the GSK3 inhibitor/Wnt pathway activator CHIR. Further investigation through immunofluorescence imaging and cell fractionation revealed a shifted membrane localization of β-catenin in CBM mutant iPSCs, revealing a novel molecular component of NKA-Wnt regulation. This study sheds light on a genetic regulation of myogenesis through the CBM of NKA and control of Wnt/β-catenin signaling.
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Affiliation(s)
- Minqi Huang
- Marshall Institute for Interdisciplinary Research (MIIR) at Marshall University, Huntington, WV 25703, USA
| | - Xiaoliang Wang
- Marshall Institute for Interdisciplinary Research (MIIR) at Marshall University, Huntington, WV 25703, USA
- Joan C. Edwards School of Medicine at Marshall University, Huntington, WV 25703, USA
| | - Moumita Banerjee
- Marshall Institute for Interdisciplinary Research (MIIR) at Marshall University, Huntington, WV 25703, USA
| | - Shreya T Mukherji
- Marshall Institute for Interdisciplinary Research (MIIR) at Marshall University, Huntington, WV 25703, USA
| | - Laura C Kutz
- Marshall Institute for Interdisciplinary Research (MIIR) at Marshall University, Huntington, WV 25703, USA
| | - Aijie Zhao
- Marshall Institute for Interdisciplinary Research (MIIR) at Marshall University, Huntington, WV 25703, USA
| | - Michael Sepanski
- Department of Embryology, Carnegie Institution for Science, 3520 San Martin Drive, Baltimore, MD 21218, USA
| | - Chen-Ming Fan
- Department of Embryology, Carnegie Institution for Science, 3520 San Martin Drive, Baltimore, MD 21218, USA
| | - Guo-Zhang Zhu
- Department of Biological Sciences, Marshall University, Huntington, WV 25703, USA
| | - Jiang Tian
- Marshall Institute for Interdisciplinary Research (MIIR) at Marshall University, Huntington, WV 25703, USA
- Joan C. Edwards School of Medicine at Marshall University, Huntington, WV 25703, USA
| | - Da-Zhi Wang
- University of South Florida Health Heart Institute, Morsani College of Medicine, University of South Florida, 560 Channelside Drive, Tampa, FL 33602, USA
| | - Hua Zhu
- Department of Surgery, The Ohio State University, 396 Biomedical Research Tower, 460 W. 12th Avenue, Columbus, OH 43210, USA
| | - Zi-Jian Xie
- Marshall Institute for Interdisciplinary Research (MIIR) at Marshall University, Huntington, WV 25703, USA
| | - Sandrine V Pierre
- Marshall Institute for Interdisciplinary Research (MIIR) at Marshall University, Huntington, WV 25703, USA
| | - Liquan Cai
- Marshall Institute for Interdisciplinary Research (MIIR) at Marshall University, Huntington, WV 25703, USA
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Ng HWY, Ogbeta JA, Clapcote SJ. Genetically altered animal models for ATP1A3-related disorders. Dis Model Mech 2021; 14:272403. [PMID: 34612482 PMCID: PMC8503543 DOI: 10.1242/dmm.048938] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Within the past 20 years, particularly with the advent of exome sequencing technologies, autosomal dominant and de novo mutations in the gene encoding the neurone-specific α3 subunit of the Na+,K+-ATPase (NKA α3) pump, ATP1A3, have been identified as the cause of a phenotypic continuum of rare neurological disorders. These allelic disorders of ATP1A3 include (in approximate order of severity/disability and onset in childhood development): polymicrogyria; alternating hemiplegia of childhood; cerebellar ataxia, areflexia, pes cavus, optic atrophy and sensorineural hearing loss syndrome; relapsing encephalopathy with cerebellar ataxia; and rapid-onset dystonia-parkinsonism. Some patients present intermediate, atypical or combined phenotypes. As these disorders are currently difficult to treat, there is an unmet need for more effective therapies. The molecular mechanisms through which mutations in ATP1A3 result in a broad range of neurological symptoms are poorly understood. However, in vivo comparative studies using genetically altered model organisms can provide insight into the biological consequences of the disease-causing mutations in NKA α3. Herein, we review the existing mouse, zebrafish, Drosophila and Caenorhabditis elegans models used to study ATP1A3-related disorders, and discuss their potential contribution towards the understanding of disease mechanisms and development of novel therapeutics.
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Affiliation(s)
- Hannah W Y Ng
- School of Biomedical Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Jennifer A Ogbeta
- School of Biomedical Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Steven J Clapcote
- School of Biomedical Sciences, University of Leeds, Leeds LS2 9JT, UK.,European Network for Research on Alternating Hemiplegia (ENRAH), 1120 Vienna, Austria
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11
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Rice C, De O, Alhadyian H, Hall S, Ward RE. Expanding the Junction: New Insights into Non-Occluding Roles for Septate Junction Proteins during Development. J Dev Biol 2021; 9:11. [PMID: 33801162 PMCID: PMC8006247 DOI: 10.3390/jdb9010011] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 03/15/2021] [Accepted: 03/17/2021] [Indexed: 12/17/2022] Open
Abstract
The septate junction (SJ) provides an occluding function for epithelial tissues in invertebrate organisms. This ability to seal the paracellular route between cells allows internal tissues to create unique compartments for organ function and endows the epidermis with a barrier function to restrict the passage of pathogens. Over the past twenty-five years, numerous investigators have identified more than 30 proteins that are required for the formation or maintenance of the SJs in Drosophila melanogaster, and have determined many of the steps involved in the biogenesis of the junction. Along the way, it has become clear that SJ proteins are also required for a number of developmental events that occur throughout the life of the organism. Many of these developmental events occur prior to the formation of the occluding junction, suggesting that SJ proteins possess non-occluding functions. In this review, we will describe the composition of SJs, taking note of which proteins are core components of the junction versus resident or accessory proteins, and the steps involved in the biogenesis of the junction. We will then elaborate on the functions that core SJ proteins likely play outside of their role in forming the occluding junction and describe studies that provide some cell biological perspectives that are beginning to provide mechanistic understanding of how these proteins function in developmental contexts.
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Affiliation(s)
- Clinton Rice
- Department of Molecular Biosciences, University of Kansas, Lawrence, KS 66045, USA; (C.R.); (H.A.)
| | - Oindrila De
- Department of Biology, Case Western Reserve University, Cleveland, OH 44106, USA;
| | - Haifa Alhadyian
- Department of Molecular Biosciences, University of Kansas, Lawrence, KS 66045, USA; (C.R.); (H.A.)
| | | | - Robert E. Ward
- Department of Biology, Case Western Reserve University, Cleveland, OH 44106, USA;
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12
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Moyes CD, Dastjerdi SH, Robertson RM. Measuring enzyme activities in crude homogenates: Na +/K +-ATPase as a case study in optimizing assays. Comp Biochem Physiol B Biochem Mol Biol 2021; 255:110577. [PMID: 33609808 DOI: 10.1016/j.cbpb.2021.110577] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 01/06/2021] [Accepted: 02/08/2021] [Indexed: 12/28/2022]
Abstract
In this review of assays of Na+/K+-ATPase (NKA), we explore the choices made by researchers assaying the enzyme to investigate its role in physiological regulation. We survey NKA structure and function in the context of how it is typically assayed, and how technical choices influence what can be said about the enzyme. In comparing different methods for extraction and assay of NKA, we identified a series of common pitfalls that compromise the veracity of results. We include experimental work to directly demonstrate how choices in detergents, salts and substrates influence NKA activities measured in crude homogenates. Our review of assay approaches integrates what is known from enzymology, biomedical physiology, cell biology and evolutionary biology, offering a more robust method for assaying the enzyme in meaningful ways, identifying caveats and future directions to explore its structure and function. The goal is to provide the sort of background on the enzyme that should be considered in exploring the function of the enzyme in comparative physiology.
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13
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Rouka E, Gourgoulianni N, Lüpold S, Hatzoglou C, Gourgoulianis K, Blanckenhorn WU, Zarogiannis SG. The Drosophila septate junctions beyond barrier function: Review of the literature, prediction of human orthologs of the SJ-related proteins and identification of protein domain families. Acta Physiol (Oxf) 2021; 231:e13527. [PMID: 32603029 DOI: 10.1111/apha.13527] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Revised: 06/20/2020] [Accepted: 06/22/2020] [Indexed: 12/20/2022]
Abstract
The involvement of Septate Junctions (SJs) in critical cellular functions that extend beyond their role as diffusion barriers in the epithelia and the nervous system has made the fruit fly an ideal model for the study of human diseases associated with impaired Tight Junction (TJ) function. In this study, we summarized current knowledge of the Drosophila melanogaster SJ-related proteins, focusing on their unconventional functions. Additionally, we sought to identify human orthologs of the corresponding genes as well as protein domain families. The systematic literature search was performed in PubMed and Scopus databases using relevant key terms. Orthologs were predicted using the DIOPT tool and aligned protein regions were determined from the Pfam database. 3-D models of the smooth SJ proteins were built on the Phyre2 and DMPFold protein structure prediction servers. A total of 30 proteins were identified as relatives to the SJ cellular structure. Key roles of these proteins, mainly in the regulation of morphogenetic events and cellular signalling, were highlighted. The investigation of protein domain families revealed that the SJ-related proteins contain conserved domains that are required not only for cell-cell interactions and cell polarity but also for cellular signalling and immunity. DIOPT analysis of orthologs identified novel human genes as putative functional homologs of the fruit fly SJ genes. A gap in our knowledge was identified regarding the domains that occur in the proteins encoded by eight SJ-associated genes. Future investigation of these domains is needed to provide functional information.
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Affiliation(s)
- Erasmia Rouka
- Department of Physiology Faculty of Medicine School of Health Sciences University of ThessalyBIOPOLIS Larissa Greece
| | - Natalia Gourgoulianni
- Department of Evolutionary Biology and Environmental Studies University of Zurich Zurich Switzerland
| | - Stefan Lüpold
- Department of Evolutionary Biology and Environmental Studies University of Zurich Zurich Switzerland
| | - Chrissi Hatzoglou
- Department of Physiology Faculty of Medicine School of Health Sciences University of ThessalyBIOPOLIS Larissa Greece
- Department of Respiratory Medicine Faculty of Medicine School of Health Sciences University of ThessalyBIOPOLIS Larissa Greece
| | - Konstantinos Gourgoulianis
- Department of Respiratory Medicine Faculty of Medicine School of Health Sciences University of ThessalyBIOPOLIS Larissa Greece
| | - Wolf U. Blanckenhorn
- Department of Evolutionary Biology and Environmental Studies University of Zurich Zurich Switzerland
| | - Sotirios G. Zarogiannis
- Department of Physiology Faculty of Medicine School of Health Sciences University of ThessalyBIOPOLIS Larissa Greece
- Department of Respiratory Medicine Faculty of Medicine School of Health Sciences University of ThessalyBIOPOLIS Larissa Greece
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14
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Yang R, Li E, Kwon YJ, Mani M, Beitel GJ. QuBiT: a quantitative tool for analyzing epithelial tubes reveals unexpected patterns of organization in the Drosophila trachea. Development 2019; 146:dev.172759. [PMID: 30967427 DOI: 10.1242/dev.172759] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Accepted: 04/03/2019] [Indexed: 01/26/2023]
Abstract
Biological tubes are essential for animal survival, and their functions are dependent on tube shape. Analyzing the contributions of cell shape and organization to the morphogenesis of small tubes has been hampered by the limitations of existing programs in quantifying cell geometry on highly curved tubular surfaces and calculating tube-specific parameters. We therefore developed QuBiT (Quantitative Tool for Biological Tubes) and used it to analyze morphogenesis of the embryonic Drosophila trachea (airway). In the main tube, we find previously unknown anterior-to-posterior (A-P) gradients of cell apical orientation and aspect ratio, and periodicity in the organization of apical cell surfaces. Inferred cell intercalation during development dampens an A-P gradient of the number of cells per cross-section of the tube, but does not change the patterns of cell connectivity. Computationally 'unrolling' the apical surface of wild-type trachea and the hindgut reveals previously unrecognized spatial patterns of the apical marker Uninflatable and a non-redundant role for the Na+/K+ ATPase in apical marker organization. These unexpected findings demonstrate the importance of a computational tool for analyzing small diameter biological tubes.
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Affiliation(s)
- Ran Yang
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208, USA
| | - Eric Li
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208, USA
| | - Yong-Jae Kwon
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208, USA
| | - Madhav Mani
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208, USA.,Department of Engineering Sciences and Applied Mathematics, Northwestern University, Evanston, IL 60208, USA.,NSF-Simons Center for Quantitative Biology, Northwestern University, Evanston, IL 60208, USA
| | - Greg J Beitel
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208, USA
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15
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Sheeja CC, Thushara VV, Divya L. Caste-Specific Expression of Na +/K +-ATPase in the Asian Weaver Ant, Oecophylla smaragdina (Fabricius, 1775). NEOTROPICAL ENTOMOLOGY 2018; 47:763-768. [PMID: 29572631 DOI: 10.1007/s13744-018-0598-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Accepted: 02/08/2018] [Indexed: 06/08/2023]
Abstract
Social insect colonies adopt different levels of survival strategies and exhibit well-defined reproductive division of labour. Oecophylla smaragdina (Fabricius, 1775) has physiological and behavioral adaptations that enable them to forage at extreme environmental conditions and are lethal to most other insects. Ion homeostasis is the key process in an organism's survival mechanism. Among ion pumps, the ATP-dependent sodium-potassium ion pump is essential for maintaining the Na+ and K+ ionic balance and is well known as the primary consumer of energy. Oecophylla smaragdina plays pivotal role as a model among social insects for understanding ion homeostasis at the organization level of the castes. We have evaluated the expression and activity of Na+/K+-ATPase among various castes of O. smaragdina (worker subcastes, queen and male). Real-time PCR and immunoblotting analyses revealed the differential expression of Na+/K+-ATPase in the castes. Significantly higher expression of Na+/K+-ATPase mRNA and protein were observed in the minor workers, queen, major workers and males respectively. These results suggest that in the weaver ant colony, the castes might have variously adapted and evolved with a well-developed ion transport mechanism which allows them to perform allocated tasks within the nest and could be a key to their adaptive benefits towards division of labour.
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Affiliation(s)
- C C Sheeja
- Dept of Animal Science, School of Biological Sciences, Central Univ of Kerala, RSTC Padanakad, Kasaragod, Kerala, 671314, India
| | - V V Thushara
- Dept of Animal Science, School of Biological Sciences, Central Univ of Kerala, RSTC Padanakad, Kasaragod, Kerala, 671314, India
| | - L Divya
- Dept of Animal Science, School of Biological Sciences, Central Univ of Kerala, RSTC Padanakad, Kasaragod, Kerala, 671314, India.
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16
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Zhou D, Fu H, Xiao L, Mo H, Zhuo H, Tian X, Lin L, Xing J, Liu Y. Fibroblast-Specific β-Catenin Signaling Dictates the Outcome of AKI. J Am Soc Nephrol 2018; 29:1257-1271. [PMID: 29343518 DOI: 10.1681/asn.2017080903] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2017] [Accepted: 12/18/2017] [Indexed: 01/10/2023] Open
Abstract
AKI is a devastating condition with high morbidity and mortality. The pathologic features of AKI are characterized by tubular injury, inflammation, and vascular impairment. Whether fibroblasts in the renal interstitium have a role in the pathogenesis of AKI is unknown. In this study, we investigated the role of fibroblast-specific β-catenin signaling in dictating the outcome of AKI, using conditional knockout mice in which β-catenin was specifically ablated in fibroblasts (Gli1-β-cat-/-). After ischemia-reperfusion injury (IRI), Gli1-β-cat-/- mice had lower serum creatinine levels and less morphologic injury than Gli1-β-cat+/+ littermate controls. Moreover, we detected fewer apoptotic cells, as well as decreased cytochrome C release; reduced expression of Bax, FasL, and p53; and increased phosphorylation of Akt, in the Gli1-β-cat-/- kidneys. Gli1-β-cat-/- kidneys also exhibited upregulated expression of proliferating cell nuclear antigen and Ki-67, which are markers of cell proliferation. Furthermore, Gli1-β-cat-/- kidneys displayed suppressed NF-κB signaling and cytokine expression and reduced infiltration of inflammatory cells. Notably, loss of β-catenin in fibroblasts induced renal expression of hepatocyte growth factor (HGF) and augmented the tyrosine phosphorylation of c-met receptor after IRI. In vitro, treatment with Wnt ligands or ectopic expression of active β-catenin inhibited HGF mRNA and protein expression and repressed HGF promoter activity. Collectively, these results suggest that fibroblast-specific β-catenin signaling can control tubular injury and repair in AKI by modulating HGF expression. Our studies uncover a previously unrecognized role for interstitial fibroblasts in the pathogenesis of AKI.
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Affiliation(s)
| | - Haiyan Fu
- State Key Laboratory of Organ Failure Research, National Clinical Research Center of Kidney Disease, Division of Nephrology, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Liangxiang Xiao
- State Key Laboratory of Organ Failure Research, National Clinical Research Center of Kidney Disease, Division of Nephrology, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | | | | | - Xiaojun Tian
- Computational and Systems Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania; and
| | - Lin Lin
- Departments of Pathology and
| | - Jianhua Xing
- Computational and Systems Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania; and
| | - Youhua Liu
- Departments of Pathology and .,State Key Laboratory of Organ Failure Research, National Clinical Research Center of Kidney Disease, Division of Nephrology, Nanfang Hospital, Southern Medical University, Guangzhou, China
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17
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Gene silencing reveals multiple functions of Na +/K +-ATPase in the salmon louse (Lepeophtheirus salmonis). Exp Parasitol 2018; 185:79-91. [PMID: 29339143 DOI: 10.1016/j.exppara.2018.01.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Revised: 10/23/2017] [Accepted: 01/03/2018] [Indexed: 11/20/2022]
Abstract
Na+/K+-ATPase has a key function in a variety of physiological processes including membrane excitability, osmoregulation, regulation of cell volume, and transport of nutrients. While knowledge about Na+/K+-ATPase function in osmoregulation in crustaceans is extensive, the role of this enzyme in other physiological and developmental processes is scarce. Here, we report characterization, transcriptional distribution and likely functions of the newly identified L. salmonis Na+/K+-ATPase (LsalNa+/K+-ATPase) α subunit in various developmental stages. The complete mRNA sequence was identified, with 3003 bp open reading frame encoding a putative protein of 1001 amino acids. Putative protein sequence of LsalNa+/K+-ATPase revealed all typical features of Na+/K+-ATPase and demonstrated high sequence identity to other invertebrate and vertebrate species. Quantitative RT-PCR analysis revealed higher LsalNa+/K+-ATPase transcript level in free-living stages in comparison to parasitic stages. In situ hybridization analysis of copepodids and adult lice revealed LsalNa+/K+-ATPase transcript localization in a wide variety of tissues such as nervous system, intestine, reproductive system, and subcuticular and glandular tissue. RNAi mediated knock-down of LsalNa+/K+-ATPase caused locomotion impairment, and affected reproduction and feeding. Morphological analysis of dsRNA treated animals revealed muscle degeneration in larval stages, severe changes in the oocyte formation and maturation in females and abnormalities in tegmental glands. Thus, the study represents an important foundation for further functional investigation and identification of physiological pathways in which Na+/K+-ATPase is directly or indirectly involved.
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18
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Lohr JN, Meinzer F, Dalla S, Romey-Glüsing R, Dobler S. The function and evolutionary significance of a triplicated Na,K-ATPase gene in a toxin-specialized insect. BMC Evol Biol 2017; 17:256. [PMID: 29246105 PMCID: PMC5732401 DOI: 10.1186/s12862-017-1097-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Accepted: 11/27/2017] [Indexed: 01/27/2023] Open
Abstract
Background The Na,K-ATPase is a vital animal cell-membrane protein that maintains the cell’s resting potential, among other functions. Cardenolides, a group of potent plant toxins, bind to and inhibit this pump. The gene encoding the α-subunit of the pump has undergone duplication events in some insect species known to feed on plants containing cardenolides. Here we test the function of these duplicated gene copies in the cardenolide-adapted milkweed bug, Oncopeltus fasciatus, which has three known copies of the gene: α1A, α1B and α1C. Results Using RT-qPCR analyses we demonstrate that the α1C is highly expressed in neural tissue, where the pump is generally thought to be most important for neuron excitability. With the use of in vivo RNAi in adult bugs we found that α1C knockdowns suffered high mortality, where as α1A and α1B did not, supporting that α1C is most important for effective ion pumping. Next we show a role for α1A and α1B in the handling of cardenolides: expression results find that both copies are primarily expressed in the Malpighian tubules, the primary insect organ responsible for excretion, and when we injected either α1A or α1B knockdowns with cardenolides this proved fatal (whereas not in controls). Conclusions These results show that the Na,K-ATPα gene-copies have taken on diverse functions. Having multiple copies of this gene appears to have allowed the newly arisen duplicates to specialize on resistance to cardenolides, whereas the ancestral copy of the pump remains comparatively sensitive, but acts as a more efficient ion carrier. Interestingly both the α1A and α1B were required for cardenolide handling, suggesting that these two copies have separate and vital functions. Gene duplications of the Na,K-ATPase thus represent an excellent example of subfunctionalization in response to a new environmental challenge. Electronic supplementary material The online version of this article (10.1186/s12862-017-1097-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Jennifer N Lohr
- Universität Hamburg, Biozentrum Grindel, Zoologisches Institut, Martin-Luther-King Pl. 3, 20146, Hamburg, Germany. .,Department of Genetics, Evolution and Environment, Institute of Healthy Ageing, University College London, WC1E 6BT, London, UK.
| | - Fee Meinzer
- Universität Hamburg, Biozentrum Grindel, Zoologisches Institut, Martin-Luther-King Pl. 3, 20146, Hamburg, Germany
| | - Safaa Dalla
- Universität Hamburg, Biozentrum Grindel, Zoologisches Institut, Martin-Luther-King Pl. 3, 20146, Hamburg, Germany
| | - Renja Romey-Glüsing
- Universität Hamburg, Biozentrum Grindel, Zoologisches Institut, Martin-Luther-King Pl. 3, 20146, Hamburg, Germany
| | - Susanne Dobler
- Universität Hamburg, Biozentrum Grindel, Zoologisches Institut, Martin-Luther-King Pl. 3, 20146, Hamburg, Germany
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19
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Dalla S, Baum M, Dobler S. Substitutions in the cardenolide binding site and interaction of subunits affect kinetics besides cardenolide sensitivity of insect Na,K-ATPase. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2017; 89:43-50. [PMID: 28866054 DOI: 10.1016/j.ibmb.2017.08.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Revised: 08/20/2017] [Accepted: 08/29/2017] [Indexed: 06/07/2023]
Abstract
Substitutions within the cardenolide target site of several insects' Na,K-ATPase α-subunits may confer resistance against toxic cardenolides. However, to which extent these substitutions alter the Na,K-ATPase's kinetic properties and how they interact with different β-subunits is not clear. The cardenolide-adapted milkweed bug Oncopeltus fasciatus possesses three paralogs of the α-subunit (A, B, and C) that differ in number and identity of resistance-conferring substitutions. We introduced these substitutions into the α-subunit of Drosophila melanogaster and combined them with the β-subunits Nrv2.2 and Nrv3. The substitutions Q111T-N122H-F786N-T797A (A-copy mimic) and Q111T-N122H-F786N (B-copy mimic) mediated high insensitivity to ouabain, yet they drastically lowered ATPase activity. Remarkably, the identity of the β-subunit was decisive and all α-subunits were less active when combined with Nrv3 than when combined with Nrv2.2. Both the substitutions and the co-expressed β-subunit strongly affected the enyzme's affinity for Na+ and K+. Na+ affinity was considerably higher for all enzymes expressed with nrv3 while expression with nrv2.2 mostly increased K+ affinity. Our results provide the first evidence that resistance against cardenolides comes at the cost of significantly altered kinetic properties of the Na,K-ATPase. The β-subunit can strongly modulate these properties but cannot fully compensate for the effect of the substitutions.
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Affiliation(s)
- Safaa Dalla
- Institute of Zoology, Universität Hamburg, Martin-Luther-King Pl. 3, 20146 Hamburg, Germany
| | - Michael Baum
- Institute of Zoology, Universität Hamburg, Martin-Luther-King Pl. 3, 20146 Hamburg, Germany
| | - Susanne Dobler
- Institute of Zoology, Universität Hamburg, Martin-Luther-King Pl. 3, 20146 Hamburg, Germany.
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20
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Petschenka G, Wagschal V, von Tschirnhaus M, Donath A, Dobler S. Convergently Evolved Toxic Secondary Metabolites in Plants Drive the Parallel Molecular Evolution of Insect Resistance. Am Nat 2017; 190:S29-S43. [DOI: 10.1086/691711] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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21
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Demirsoy S, Martin S, Motamedi S, van Veen S, Holemans T, Van den Haute C, Jordanova A, Baekelandt V, Vangheluwe P, Agostinis P. ATP13A2/PARK9 regulates endo-/lysosomal cargo sorting and proteostasis through a novel PI(3, 5)P2-mediated scaffolding function. Hum Mol Genet 2017; 26:1656-1669. [PMID: 28334751 DOI: 10.1093/hmg/ddx070] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Accepted: 02/20/2017] [Indexed: 12/20/2022] Open
Abstract
ATP13A2 (also called PARK9), is a transmembrane endo-/lysosomal-associated P5 type transport ATPase. Loss-of-function mutations in ATP13A2 result in the Kufor-Rakeb Syndrome (KRS), a form of autosomal Parkinson's disease (PD). In spite of a growing interest in ATP13A2, very little is known about its physiological role in stressed cells. Recent studies suggest that the N-terminal domain of ATP13A2 may hold key regulatory functions, but their nature remains incompletely understood. To this end, we generated a set of melanoma and neuroblastoma cell lines stably overexpressing wild-type (WT), catalytically inactive (D508N) and N-terminal mutants, or shRNA against ATP13A2. We found that under proteotoxic stress conditions, evoked by the proteasome inhibitor Bortezomib, endo-/lysosomal associated full-length ATP13A2 WT, catalytically-inactive or N-terminal fragment mutants, reduced the intracellular accumulation of ubiquitin-conjugated (Ub) proteins, independent of autophagic degradation. In contrast, ATP13A2 silencing increased the intracellular accumulation of Ub-proteins, a pattern also observed in patient-derived fibroblasts harbouring ATP13A2 loss-of function mutations. In treated cells, ATP13A2 evoked endocytic vesicle relocation and increased cargo export through nanovesicles. Expression of an ATP13A2 mutant abrogating PI(3,5)P2 binding or chemical inhibition of the PI(3,5)P2-generating enzyme PIKfyve, compromised vesicular trafficking/nanovesicles export and rescued intracellular accumulation of Ub-proteins in response to proteasomal inhibition. Hence, our study unravels a novel activity-independent scaffolding role of ATP13A2 in trafficking/export of intracellular cargo in response to proteotoxic stress.
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Affiliation(s)
- S Demirsoy
- Laboratory for Cell Death Research and Therapy, Department of Cellular and Molecular Medicine, University of Leuven (KU Leuven)
| | - S Martin
- Laboratory of Cellular Transport Systems, Department of Cellular and Molecular Medicine, University of Leuven (KU Leuven), Campus Gasthuisberg, O&N1, Herestraat 49, Box 802, B-3000 Leuven, Belgium
| | - S Motamedi
- Laboratory for Cell Death Research and Therapy, Department of Cellular and Molecular Medicine, University of Leuven (KU Leuven)
| | - S van Veen
- Laboratory of Cellular Transport Systems, Department of Cellular and Molecular Medicine, University of Leuven (KU Leuven), Campus Gasthuisberg, O&N1, Herestraat 49, Box 802, B-3000 Leuven, Belgium
| | - T Holemans
- Laboratory of Cellular Transport Systems, Department of Cellular and Molecular Medicine, University of Leuven (KU Leuven), Campus Gasthuisberg, O&N1, Herestraat 49, Box 802, B-3000 Leuven, Belgium
| | - C Van den Haute
- Research Group for Neurobiology and Gene Therapy, Department of Neurosciences, University of Leuven (KU Leuven), B3000 Leuven, Belgium
| | - A Jordanova
- Molecular Neurogenomics Group, VIB Center for Molecular Neurology, University of Antwerp, 2610 Antwerpen, Belgium
- Molecular Medicine Center, Department of Medical Chemistry and Biochemistry, Medical University-Sofia, 1431 Sofia, Bulgaria
| | - V Baekelandt
- Research Group for Neurobiology and Gene Therapy, Department of Neurosciences, University of Leuven (KU Leuven), B3000 Leuven, Belgium
| | - P Vangheluwe
- Laboratory of Cellular Transport Systems, Department of Cellular and Molecular Medicine, University of Leuven (KU Leuven), Campus Gasthuisberg, O&N1, Herestraat 49, Box 802, B-3000 Leuven, Belgium
| | - P Agostinis
- Laboratory for Cell Death Research and Therapy, Department of Cellular and Molecular Medicine, University of Leuven (KU Leuven)
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22
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Harmansa S, Alborelli I, Bieli D, Caussinus E, Affolter M. A nanobody-based toolset to investigate the role of protein localization and dispersal in Drosophila. eLife 2017; 6. [PMID: 28395731 PMCID: PMC5388529 DOI: 10.7554/elife.22549] [Citation(s) in RCA: 76] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2016] [Accepted: 03/14/2017] [Indexed: 12/26/2022] Open
Abstract
The role of protein localization along the apical-basal axis of polarized cells is difficult to investigate in vivo, partially due to lack of suitable tools. Here, we present the GrabFP system, a collection of four nanobody-based GFP-traps that localize to defined positions along the apical-basal axis. We show that the localization preference of the GrabFP traps can impose a novel localization on GFP-tagged target proteins and results in their controlled mislocalization. These new tools were used to mislocalize transmembrane and cytoplasmic GFP fusion proteins in the Drosophila wing disc epithelium and to investigate the effect of protein mislocalization. Furthermore, we used the GrabFP system as a tool to study the extracellular dispersal of the Decapentaplegic (Dpp) protein and show that the Dpp gradient forming in the lateral plane of the Drosophila wing disc epithelium is essential for patterning of the wing imaginal disc.
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Affiliation(s)
- Stefan Harmansa
- Growth and Development, Biozentrum, University of Basel, Basel, Switzerland
| | - Ilaria Alborelli
- Growth and Development, Biozentrum, University of Basel, Basel, Switzerland
| | - Dimitri Bieli
- Growth and Development, Biozentrum, University of Basel, Basel, Switzerland
| | - Emmanuel Caussinus
- Growth and Development, Biozentrum, University of Basel, Basel, Switzerland.,Institute of Molecular Life Sciences, University of Zurich, Zurich, Switzerland
| | - Markus Affolter
- Growth and Development, Biozentrum, University of Basel, Basel, Switzerland
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23
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Dalla S, Dobler S. Gene duplications circumvent trade-offs in enzyme function: Insect adaptation to toxic host plants. Evolution 2016; 70:2767-2777. [DOI: 10.1111/evo.13077] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Revised: 09/26/2016] [Accepted: 09/26/2016] [Indexed: 01/20/2023]
Affiliation(s)
- Safaa Dalla
- Molecular Evolutionary Biology, Zoological Institute, Biocenter Grindel; University of Hamburg; 20146 Hamburg Germany
| | - Susanne Dobler
- Molecular Evolutionary Biology, Zoological Institute, Biocenter Grindel; University of Hamburg; 20146 Hamburg Germany
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24
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Harden N, Wang SJH, Krieger C. Making the connection – shared molecular machinery and evolutionary links underlie the formation and plasticity of occluding junctions and synapses. J Cell Sci 2016; 129:3067-76. [DOI: 10.1242/jcs.186627] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
ABSTRACT
The pleated septate junction (pSJ), an ancient structure for cell–cell contact in invertebrate epithelia, has protein components that are found in three more-recent junctional structures, the neuronal synapse, the paranodal region of the myelinated axon and the vertebrate epithelial tight junction. These more-recent structures appear to have evolved through alterations of the ancestral septate junction. During its formation in the developing animal, the pSJ exhibits plasticity, although the final structure is extremely robust. Similar to the immature pSJ, the synapse and tight junctions both exhibit plasticity, and we consider evidence that this plasticity comes at least in part from the interaction of members of the immunoglobulin cell adhesion molecule superfamily with highly regulated membrane-associated guanylate kinases. This plasticity regulation probably arose in order to modulate the ancestral pSJ and is maintained in the derived structures; we suggest that it would be beneficial when studying plasticity of one of these structures to consider the literature on the others. Finally, looking beyond the junctions, we highlight parallels between epithelial and synaptic membranes, which both show a polarized distribution of many of the same proteins – evidence that determinants of apicobasal polarity in epithelia also participate in patterning of the synapse.
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Affiliation(s)
- Nicholas Harden
- Simon Fraser University, Department of Molecular Biology and Biochemistry, Burnaby, British Columbia V5A 1S6, Canada
| | - Simon Ji Hau Wang
- Simon Fraser University, Department of Molecular Biology and Biochemistry, Burnaby, British Columbia V5A 1S6, Canada
- Simon Fraser University, Department of Biomedical Physiology and Kinesiology, Burnaby, British Columbia V5A 1S6, Canada
| | - Charles Krieger
- Simon Fraser University, Department of Biomedical Physiology and Kinesiology, Burnaby, British Columbia V5A 1S6, Canada
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25
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Hatzold J, Beleggia F, Herzig H, Altmüller J, Nürnberg P, Bloch W, Wollnik B, Hammerschmidt M. Tumor suppression in basal keratinocytes via dual non-cell-autonomous functions of a Na,K-ATPase beta subunit. eLife 2016; 5. [PMID: 27240166 PMCID: PMC4973367 DOI: 10.7554/elife.14277] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Accepted: 05/28/2016] [Indexed: 01/11/2023] Open
Abstract
The molecular pathways underlying tumor suppression are incompletely understood. Here, we identify cooperative non-cell-autonomous functions of a single gene that together provide a novel mechanism of tumor suppression in basal keratinocytes of zebrafish embryos. A loss-of-function mutation in atp1b1a, encoding the beta subunit of a Na,K-ATPase pump, causes edema and epidermal malignancy. Strikingly, basal cell carcinogenesis only occurs when Atp1b1a function is compromised in both the overlying periderm (resulting in compromised epithelial polarity and adhesiveness) and in kidney and heart (resulting in hypotonic stress). Blockade of the ensuing PI3K-AKT-mTORC1-NFκB-MMP9 pathway activation in basal cells, as well as systemic isotonicity, prevents malignant transformation. Our results identify hypotonic stress as a (previously unrecognized) contributor to tumor development and establish a novel paradigm of tumor suppression.
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Affiliation(s)
- Julia Hatzold
- Institute for Zoology, Developmental Biology Unit, University of Cologne, Cologne, Germany.,Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany
| | - Filippo Beleggia
- Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany.,Institute of Human Genetics, University Hospital Cologne, Cologne, Germany.,Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases, University of Cologne, Cologne, Germany
| | - Hannah Herzig
- Institute of Cardiology and Sports Medicine, German Sport University Cologne, Cologne, Germany
| | - Janine Altmüller
- Institute of Human Genetics, University Hospital Cologne, Cologne, Germany.,Cologne Center for Genomics, University of Cologne, Cologne, Germany
| | - Peter Nürnberg
- Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany.,Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases, University of Cologne, Cologne, Germany.,Cologne Center for Genomics, University of Cologne, Cologne, Germany
| | - Wilhelm Bloch
- Institute of Cardiology and Sports Medicine, German Sport University Cologne, Cologne, Germany
| | - Bernd Wollnik
- Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany.,Institute of Human Genetics, University Hospital Cologne, Cologne, Germany.,Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases, University of Cologne, Cologne, Germany.,Institute of Human Genetics, University Medical Center Göttingen, Göttingen, Germany
| | - Matthias Hammerschmidt
- Institute for Zoology, Developmental Biology Unit, University of Cologne, Cologne, Germany.,Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany.,Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases, University of Cologne, Cologne, Germany
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β1-Na(+),K(+)-ATPase gene therapy upregulates tight junctions to rescue lipopolysaccharide-induced acute lung injury. Gene Ther 2016; 23:489-99. [PMID: 26910760 DOI: 10.1038/gt.2016.19] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Revised: 01/08/2016] [Accepted: 01/19/2016] [Indexed: 01/05/2023]
Abstract
Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) are associated with diverse disorders and characterized by disruption of the alveolar-capillary barrier, leakage of edema fluid into the lung, and substantial inflammation leading to acute respiratory failure. Gene therapy is a potentially powerful approach to treat ALI/ARDS through repair of alveolar epithelial function. Herein, we show that delivery of a plasmid expressing β1-subunit of the Na(+),K(+)-ATPase (β1-Na(+),K(+)-ATPase) alone or in combination with epithelial sodium channel (ENaC) α1-subunit using electroporation not only protected from subsequent lipopolysaccharide (LPS)-mediated lung injury, but also treated injured lungs. However, transfer of α1-subunit of ENaC (α1-ENaC) alone only provided protection benefit rather than treatment benefit although alveolar fluid clearance had been remarkably enhanced. Gene transfer of β1-Na(+),K(+)-ATPase, but not α1-ENaC, not only enhanced expression of tight junction protein zona occludins-1 (ZO-1) and occludin both in cultured cells and in mouse lungs, but also reduced pre-existing increase of lung permeability in vivo. These results demonstrate that gene transfer of β1-Na(+),K(+)-ATPase upregulates tight junction formation and therefore treats lungs with existing injury, whereas delivery of α1-ENaC only maintains pre-existing tight junction but not for generation. This indicates that the restoration of epithelial/endothelial barrier function may provide better treatment of ALI/ARDS.
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27
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Thabet R, Rouault JD, Ayadi H, Leignel V. Structural analysis of the α subunit of Na(+)/K(+) ATPase genes in invertebrates. Comp Biochem Physiol B Biochem Mol Biol 2016; 196-197:11-18. [PMID: 26812300 DOI: 10.1016/j.cbpb.2016.01.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2015] [Revised: 01/20/2016] [Accepted: 01/21/2016] [Indexed: 01/18/2023]
Abstract
The Na(+)/K(+) ATPase is a ubiquitous pump coordinating the transport of Na(+) and K(+) across the membrane of cells and its role is fundamental to cellular functions. It is heteromer in eukaryotes including two or three subunits (α, β and γ which is specific to the vertebrates). The catalytic functions of the enzyme have been attributed to the α subunit. Several complete α protein sequences are available, but only few gene structures were characterized. We identified the genomic sequences coding the α-subunit of the Na(+)/K(+) ATPase, from the whole-genome shotgun contigs (WGS), NCBI Genomes (chromosome), Genomic Survey Sequences (GSS) and High Throughput Genomic Sequences (HTGS) databases across distinct phyla. One copy of the α subunit gene was found in Annelida, Arthropoda, Cnidaria, Echinodermata, Hemichordata, Mollusca, Placozoa, Porifera, Platyhelminthes, Urochordata, but the nematodes seem to possess 2 to 4 copies. The number of introns varied from 0 (Platyhelminthes) to 26 (Porifera); and their localization and length are also highly variable. Molecular phylogenies (Maximum Likelihood and Maximum Parsimony methods) showed some clusters constituted by (Chordata/(Echinodermata/Hemichordata)) or (Plathelminthes/(Annelida/Mollusca)) and a basal position for Porifera. These structural analyses increase our knowledge about the evolutionary events of the α subunit genes in the invertebrates.
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Affiliation(s)
- Rahma Thabet
- University of Sfax, Laboratory of Biodiversity and Aquatic Ecosystems UR/11ES72, Ecology and Planktonology, Department of Life Sciences, Road Soukra Km 3.5, BP1171, 3000, Sfax, Tunisia
| | - J-D Rouault
- Laboratoire Evolution, Genomes et Speciation, UPR9034, CNRS, 91198 Gif-sur-Yvette, France
| | - Habib Ayadi
- University of Sfax, Laboratory of Biodiversity and Aquatic Ecosystems UR/11ES72, Ecology and Planktonology, Department of Life Sciences, Road Soukra Km 3.5, BP1171, 3000, Sfax, Tunisia
| | - Vincent Leignel
- Université du Maine, Laboratoire Mer Molecule Sante EA 2160 FR-CNRS 3473 IUML, 72085 Le Mans, France.
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28
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Occluding junctions of invertebrate epithelia. J Comp Physiol B 2015; 186:17-43. [DOI: 10.1007/s00360-015-0937-1] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Revised: 09/12/2015] [Accepted: 09/22/2015] [Indexed: 01/30/2023]
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29
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Damulewicz M, Loboda A, Bukowska-Strakova K, Jozkowicz A, Dulak J, Pyza E. Clock and clock-controlled genes are differently expressed in the retina, lamina and in selected cells of the visual system of Drosophila melanogaster. Front Cell Neurosci 2015; 9:353. [PMID: 26441524 PMCID: PMC4569741 DOI: 10.3389/fncel.2015.00353] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2015] [Accepted: 08/24/2015] [Indexed: 11/13/2022] Open
Abstract
The retina and the first optic neuropil (lamina) of Drosophila show circadian rhythms in various processes. To learn about the regulation of circadian rhythms in the retina and lamina and in two cell types, glial and the lamina L2 interneurons, we examined expression of the following clock genes; per, tim, clk, and cry and clock-controlled genes (ccgs); Atpα, nrv2, brp, Pdfr. We found that the expression of gene studied is specific for the retina and lamina. The rhythms of per and tim expression in the retina and glial cells are similar to that observed in the whole head and in clock neurons, while they differ in the lamina and L2 cells. In both the retina and lamina, CRY seems to be a repressor of clk expression. In L2 interneurons per expression is not cyclic indicating the other function of PER in those cells than in the circadian molecular clock. In contrast to per and tim, the pattern of clk and cry expression is similar in both the retina and lamina. The retina holds the autonomous oscillators but the expression of cry and ccgs, Atpα and nrv2, is also regulated by inputs from the pacemaker transmitted by PDF and ITP neuropeptides.
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Affiliation(s)
- Milena Damulewicz
- Department of Cell Biology and Imaging, Institute of Zoology, Faculty of Biology and Earth Sciences, Jagiellonian University Krakow, Poland
| | - Agnieszka Loboda
- Department of Medical Biotechnology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University Krakow, Poland
| | - Karolina Bukowska-Strakova
- Department of Medical Biotechnology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University Krakow, Poland ; Department of Clinical Immunology and Transplantology, Polish-American Institute of Pediatrics, Medical College, Jagiellonian University Krakow, Poland
| | - Alicja Jozkowicz
- Department of Medical Biotechnology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University Krakow, Poland
| | - Jozef Dulak
- Department of Medical Biotechnology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University Krakow, Poland
| | - Elzbieta Pyza
- Department of Cell Biology and Imaging, Institute of Zoology, Faculty of Biology and Earth Sciences, Jagiellonian University Krakow, Poland
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30
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Levin M. Molecular bioelectricity: how endogenous voltage potentials control cell behavior and instruct pattern regulation in vivo. Mol Biol Cell 2015; 25:3835-50. [PMID: 25425556 PMCID: PMC4244194 DOI: 10.1091/mbc.e13-12-0708] [Citation(s) in RCA: 221] [Impact Index Per Article: 24.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
In addition to biochemical gradients and transcriptional networks, cell behavior is regulated by endogenous bioelectrical cues originating in the activity of ion channels and pumps, operating in a wide variety of cell types. Instructive signals mediated by changes in resting potential control proliferation, differentiation, cell shape, and apoptosis of stem, progenitor, and somatic cells. Of importance, however, cells are regulated not only by their own Vmem but also by the Vmem of their neighbors, forming networks via electrical synapses known as gap junctions. Spatiotemporal changes in Vmem distribution among nonneural somatic tissues regulate pattern formation and serve as signals that trigger limb regeneration, induce eye formation, set polarity of whole-body anatomical axes, and orchestrate craniofacial patterning. New tools for tracking and functionally altering Vmem gradients in vivo have identified novel roles for bioelectrical signaling and revealed the molecular pathways by which Vmem changes are transduced into cascades of downstream gene expression. Because channels and gap junctions are gated posttranslationally, bioelectrical networks have their own characteristic dynamics that do not reduce to molecular profiling of channel expression (although they couple functionally to transcriptional networks). The recent data provide an exciting opportunity to crack the bioelectric code, and learn to program cellular activity at the level of organs, not only cell types. The understanding of how patterning information is encoded in bioelectrical networks, which may require concepts from computational neuroscience, will have transformative implications for embryogenesis, regeneration, cancer, and synthetic bioengineering.
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Affiliation(s)
- Michael Levin
- Biology Department, Center for Regenerative and Developmental Biology, Tufts University, Medford, MA 02155-4243
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31
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Dong B, Hayashi S. Shaping of biological tubes by mechanical interaction of cell and extracellular matrix. Curr Opin Genet Dev 2015; 32:129-34. [DOI: 10.1016/j.gde.2015.02.009] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2014] [Revised: 02/14/2015] [Accepted: 02/21/2015] [Indexed: 01/19/2023]
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32
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Rossier BC, Baker ME, Studer RA. Epithelial sodium transport and its control by aldosterone: the story of our internal environment revisited. Physiol Rev 2015; 95:297-340. [PMID: 25540145 DOI: 10.1152/physrev.00011.2014] [Citation(s) in RCA: 155] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Transcription and translation require a high concentration of potassium across the entire tree of life. The conservation of a high intracellular potassium was an absolute requirement for the evolution of life on Earth. This was achieved by the interplay of P- and V-ATPases that can set up electrochemical gradients across the cell membrane, an energetically costly process requiring the synthesis of ATP by F-ATPases. In animals, the control of an extracellular compartment was achieved by the emergence of multicellular organisms able to produce tight epithelial barriers creating a stable extracellular milieu. Finally, the adaptation to a terrestrian environment was achieved by the evolution of distinct regulatory pathways allowing salt and water conservation. In this review we emphasize the critical and dual role of Na(+)-K(+)-ATPase in the control of the ionic composition of the extracellular fluid and the renin-angiotensin-aldosterone system (RAAS) in salt and water conservation in vertebrates. The action of aldosterone on transepithelial sodium transport by activation of the epithelial sodium channel (ENaC) at the apical membrane and that of Na(+)-K(+)-ATPase at the basolateral membrane may have evolved in lungfish before the emergence of tetrapods. Finally, we discuss the implication of RAAS in the origin of the present pandemia of hypertension and its associated cardiovascular diseases.
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Affiliation(s)
- Bernard C Rossier
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland; Division of Nephrology-Hypertension, University of California San Diego, La Jolla, California; and Institute of Structural and Molecular Biology, Division of Biosciences, University College London, London, United Kingdom
| | - Michael E Baker
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland; Division of Nephrology-Hypertension, University of California San Diego, La Jolla, California; and Institute of Structural and Molecular Biology, Division of Biosciences, University College London, London, United Kingdom
| | - Romain A Studer
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland; Division of Nephrology-Hypertension, University of California San Diego, La Jolla, California; and Institute of Structural and Molecular Biology, Division of Biosciences, University College London, London, United Kingdom
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33
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Limmer S, Weiler A, Volkenhoff A, Babatz F, Klämbt C. The Drosophila blood-brain barrier: development and function of a glial endothelium. Front Neurosci 2014; 8:365. [PMID: 25452710 PMCID: PMC4231875 DOI: 10.3389/fnins.2014.00365] [Citation(s) in RCA: 138] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2014] [Accepted: 10/23/2014] [Indexed: 01/01/2023] Open
Abstract
The efficacy of neuronal function requires a well-balanced extracellular ion homeostasis and a steady supply with nutrients and metabolites. Therefore, all organisms equipped with a complex nervous system developed a so-called blood-brain barrier, protecting it from an uncontrolled entry of solutes, metabolites or pathogens. In higher vertebrates, this diffusion barrier is established by polarized endothelial cells that form extensive tight junctions, whereas in lower vertebrates and invertebrates the blood-brain barrier is exclusively formed by glial cells. Here, we review the development and function of the glial blood-brain barrier of Drosophila melanogaster. In the Drosophila nervous system, at least seven morphologically distinct glial cell classes can be distinguished. Two of these glial classes form the blood-brain barrier. Perineurial glial cells participate in nutrient uptake and establish a first diffusion barrier. The subperineurial glial (SPG) cells form septate junctions, which block paracellular diffusion and thus seal the nervous system from the hemolymph. We summarize the molecular basis of septate junction formation and address the different transport systems expressed by the blood-brain barrier forming glial cells.
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Affiliation(s)
- Stefanie Limmer
- Institut für Neuro- und Verhaltensbiologie, Universität Münster Münster, Germany
| | - Astrid Weiler
- Institut für Neuro- und Verhaltensbiologie, Universität Münster Münster, Germany
| | - Anne Volkenhoff
- Institut für Neuro- und Verhaltensbiologie, Universität Münster Münster, Germany
| | - Felix Babatz
- Institut für Neuro- und Verhaltensbiologie, Universität Münster Münster, Germany
| | - Christian Klämbt
- Institut für Neuro- und Verhaltensbiologie, Universität Münster Münster, Germany
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34
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Ganot P, Zoccola D, Tambutté E, Voolstra CR, Aranda M, Allemand D, Tambutté S. Structural molecular components of septate junctions in cnidarians point to the origin of epithelial junctions in eukaryotes. Mol Biol Evol 2014; 32:44-62. [PMID: 25246700 DOI: 10.1093/molbev/msu265] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Septate junctions (SJs) insure barrier properties and control paracellular diffusion of solutes across epithelia in invertebrates. However, the origin and evolution of their molecular constituents in Metazoa have not been firmly established. Here, we investigated the genomes of early branching metazoan representatives to reconstruct the phylogeny of the molecular components of SJs. Although Claudins and SJ cytoplasmic adaptor components appeared successively throughout metazoan evolution, the structural components of SJs arose at the time of Placozoa/Cnidaria/Bilateria radiation. We also show that in the scleractinian coral Stylophora pistillata, the structural SJ component Neurexin IV colocalizes with the cortical actin network at the apical border of the cells, at the place of SJs. We propose a model for SJ components in Cnidaria. Moreover, our study reveals an unanticipated diversity of SJ structural component variants in cnidarians. This diversity correlates with gene-specific expression in calcifying and noncalcifying tissues, suggesting specific paracellular pathways across the cell layers of these diploblastic animals.
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Affiliation(s)
- Philippe Ganot
- Marine Biology Department, Centre Scientifique de Monaco, Quai Antoine Premier, Monaco
| | - Didier Zoccola
- Marine Biology Department, Centre Scientifique de Monaco, Quai Antoine Premier, Monaco
| | - Eric Tambutté
- Marine Biology Department, Centre Scientifique de Monaco, Quai Antoine Premier, Monaco
| | - Christian R Voolstra
- Red Sea Research Center, King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
| | - Manuel Aranda
- Red Sea Research Center, King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
| | - Denis Allemand
- Marine Biology Department, Centre Scientifique de Monaco, Quai Antoine Premier, Monaco
| | - Sylvie Tambutté
- Marine Biology Department, Centre Scientifique de Monaco, Quai Antoine Premier, Monaco
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35
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Izumi Y, Furuse M. Molecular organization and function of invertebrate occluding junctions. Semin Cell Dev Biol 2014; 36:186-93. [PMID: 25239398 DOI: 10.1016/j.semcdb.2014.09.009] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2014] [Revised: 08/25/2014] [Accepted: 09/01/2014] [Indexed: 12/31/2022]
Abstract
Septate junctions (SJs) are specialized intercellular junctions that function as permeability barriers to restrict the free diffusion of solutes through the paracellular routes in invertebrate epithelia. SJs are subdivided into several morphological types that vary among different animal phyla. In several phyla, different types of SJ have been described in different epithelia within an individual. Arthropods have two types of SJs: pleated SJs (pSJs) and smooth SJs (sSJs), found in ectodermally and endodermally derived epithelia, respectively. Several lines of Drosophila research have identified and characterized a large number of pSJ-associated proteins. Two sSJ-specific proteins have been recently reported. Molecular dissection of SJs in Drosophila and animals in other phyla will lead to a better understanding of the functional differences among SJ types and of evolutionary aspects of these permeability barriers.
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Affiliation(s)
- Yasushi Izumi
- Division of Cell Biology, Department of Physiology and Cell Biology, Graduate School of Medicine, Kobe University, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan.
| | - Mikio Furuse
- Division of Cell Biology, Department of Physiology and Cell Biology, Graduate School of Medicine, Kobe University, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan; Division of Cerebral Structure, National Institute for Physiological Sciences, Okazaki, Aichi 444-8787, Japan
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36
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Loss of Na(+)/K(+)-ATPase in Drosophila photoreceptors leads to blindness and age-dependent neurodegeneration. Exp Neurol 2014; 261:791-801. [PMID: 25205229 DOI: 10.1016/j.expneurol.2014.08.025] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2014] [Revised: 08/19/2014] [Accepted: 08/22/2014] [Indexed: 11/20/2022]
Abstract
The activity of Na(+)/K(+)-ATPase establishes transmembrane ion gradients and is essential to cell function and survival. Either dysregulation or deficiency of neuronal Na(+)/K(+)-ATPase has been implicated in the pathogenesis of many neurodegenerative disorders such as Alzheimer's disease, Parkinson's disease and rapid-onset dystonia Parkinsonism. However, genetic evidence that directly links neuronal Na(+)/K(+)-ATPase deficiency to in vivo neurodegeneration has been lacking. In this study, we use Drosophila photoreceptors to investigate the cell-autonomous effects of neuronal Na(+)/K(+) ATPase. Loss of ATPα, an α subunit of Na(+)/K(+)-ATPase, in photoreceptors through UAS/Gal4-mediated RNAi eliminated the light-triggered depolarization of the photoreceptors, rendering the fly virtually blind in behavioral assays. Intracellular recordings indicated that ATPα knockdown photoreceptors were already depolarized in the dark, which was due to a loss of intracellular K(+). Importantly, ATPα knockdown resulted in the degeneration of photoreceptors in older flies. This degeneration was independent of light and showed characteristics of apoptotic/hybrid cell death as observed via electron microscopy analysis. Loss of Nrv3, a Na(+)/K(+)-ATPase β subunit, partially reproduced the signaling and degenerative defects observed in ATPα knockdown flies. Thus, the loss of Na(+)/K(+)-ATPase not only eradicates visual function but also causes age-dependent degeneration in photoreceptors, confirming the link between neuronal Na(+)/K(+) ATPase deficiency and in vivo neurodegeneration. This work also establishes Drosophila photoreceptors as a genetic model for studying the cell-autonomous mechanisms underlying neuronal Na(+)/K(+) ATPase deficiency-mediated neurodegeneration.
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37
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Bätz T, Förster D, Luschnig S. The transmembrane protein Macroglobulin complement-related is essential for septate junction formation and epithelial barrier function in Drosophila. Development 2014; 141:899-908. [PMID: 24496626 DOI: 10.1242/dev.102160] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Occluding cell-cell junctions in epithelia form physical barriers that separate different membrane domains, restrict paracellular diffusion and prevent pathogens from spreading across tissues. In invertebrates, these functions are provided by septate junctions (SJs), the functional equivalent of vertebrate tight junctions. How the diverse functions of SJs are integrated and modulated in a multiprotein complex is not clear, and many SJ components are still unknown. Here we report the identification of Macroglobulin complement-related (Mcr), a member of the conserved α-2-macroglobulin (α2M) complement protein family, as a novel SJ-associated protein in Drosophila. Whereas α2M complement proteins are generally known as secreted factors that bind to surfaces of pathogens and target them for phagocytic uptake, Mcr represents an unusual α2M protein with a predicted transmembrane domain. We show that Mcr protein localizes to lateral membranes of epithelial cells, where its distribution overlaps with SJs. Several SJ components are required for the correct localization of Mcr. Conversely, Mcr is required in a cell-autonomous fashion for the correct membrane localization of SJ components, indicating that membrane-bound rather than secreted Mcr isoforms are involved in SJ formation. Finally, we show that loss of Mcr function leads to morphological, ultrastructural and epithelial barrier defects resembling mutants lacking SJ components. Our results, along with previous findings on the role of Mcr in phagocytosis, suggest that Mcr plays dual roles in epithelial barrier formation and innate immunity. Thus, Mcr represents a novel paradigm for investigating functional links between occluding junction formation and pathogen defense mechanisms.
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Affiliation(s)
- Tilmann Bätz
- Institute of Molecular Life Sciences and PhD Program in Molecular Life Sciences, University of Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland
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38
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Chan SH, Leu WJ, Hsu LC, Chang HS, Hwang TL, Chen IS, Chen CS, Guh JH. Reevesioside F induces potent and efficient anti-proliferative and apoptotic activities through Na⁺/K⁺-ATPase α3 subunit-involved mitochondrial stress and amplification of caspase cascades. Biochem Pharmacol 2013; 86:1564-75. [PMID: 24099795 DOI: 10.1016/j.bcp.2013.09.021] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2013] [Revised: 09/26/2013] [Accepted: 09/27/2013] [Indexed: 11/28/2022]
Abstract
Reevesioside F, isolated from Reevesia formosana, induced anti-proliferative activity that was highly correlated with the expression of Na⁺/K⁺-ATPase α₃ subunit in several cell lines, including human leukemia HL-60 and Jurkat cells, and some other cell lines. Knockdown of α₃ subunit significantly inhibited cell apoptosis suggesting a crucial role of the α₃ subunit. Reevesioside F induced a rapid down-regulation of survivin protein, followed by release of cytochrome c from mitochondria and loss of mitochondrial membrane potential (ΔΨm). Further examination demonstrated the mitochondrial damage in leukemic cells through Mcl-1 down-regulation, Noxa up-regulation and an increase of the formation of truncated Bid, tBim and a 23-kDa cleaved Bcl-2 fragment. Furthermore, reevesioside F induced an increase of mitochondria-associated acetyl α-tubulin that may also contribute to apoptosis. The caspase cascade was profoundly activated by reevesioside F. Notably, the specific caspase-3 inhibitor z-DEVD-fmk significantly blunted reevesioside F-induced loss of ΔΨm and apoptosis, suggesting that caspase-3 activation may further amplify mitochondrial damage and apoptotic signaling cascade. In spite of being a cardiac glycoside, reevesioside F did not increase the intracellular Ca²⁺ levels. Moreover, CGP-37157 which blocked Na⁺/Ca²⁺ exchanger on plasma membrane and mitochondria did not modify reevesioside F-mediated effect. In summary, the data suggest that reevesioside F induces apoptosis through the down-regulation of survivin and Mcl-1, and the formation of pro-apoptotic fragments from Bcl-2 family members. The loss of ΔΨm and mitochondrial damage are responsible for the activation of caspases. Moreover, the amplification of caspase-3-mediated signaling pathway contributes largely to the execution of apoptosis in leukemic cells.
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Affiliation(s)
- She-Hung Chan
- School of Pharmacy, National Taiwan University, No.1, Sect. 1, Jen-Ai Rd, Taipei 100, Taiwan
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Doğanli C, Oxvig C, Lykke-Hartmann K. Zebrafish as a novel model to assess Na+/K(+)-ATPase-related neurological disorders. Neurosci Biobehav Rev 2013; 37:2774-87. [PMID: 24091024 DOI: 10.1016/j.neubiorev.2013.09.013] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2013] [Revised: 08/08/2013] [Accepted: 09/23/2013] [Indexed: 11/26/2022]
Abstract
Modeling neurological disorders using zebrafish increases rapidly as this model system allows easy access to all developmental stages and imaging of pathological processes. A surprising degree of functional conservation has been demonstrated between human genes implicated in neurodegenerative diseases and their zebrafish orthologues. Zebrafish offers rapid high throughput screening of therapeutic compounds and live imaging of pathogenic mechanisms in vivo. Several recent zebrafish studies functionally assessed the role of the sodium-potassium pump (Na(+)/K(+)-ATPase). The Na(+)/K(+)-ATPase maintains the electrochemical gradients across the plasma membrane, essential for e.g. signaling, secondary active transport, glutamate re-uptake and neuron excitability in animal cells. Na(+)/K(+)-ATPase mutations are associated with neurological disorders, where mutations in the Na(+)/K(+)-ATPase α2 and α3 isoforms cause Familial hemiplegic migraine type 2 (FHM2) and Rapid-onset dystonia-parkinsonism (RDP)/Alternating hemiplegic childhood (AHC), respectively. In zebrafish, knock-down of Na(+)/K(+)-ATPase isoforms included skeletal and heart muscle defects, impaired embryonic motility, depolarized Rohon-beard neurons and abrupt brain ventricle development. In this review, we discuss zebrafish as a model to assess Na(+)/K(+)-ATPase isoform functions. Furthermore, studies investigating proteomic changes in both α2- and α3-isoform deficient embryos and their potential connections to the Na(+)/K(+)-ATPase functions will be discussed.
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Affiliation(s)
- Canan Doğanli
- Centre for Membrane Pumps in Cells and Disease-PUMPKIN, Danish National Research Foundation, Copenhagen, Denmark; Aarhus University, Department of Biomedicine, Ole Worms Allé 3, Building 1171, DK-8000 Aarhus, Denmark; Aarhus University, Department of Molecular Biology and Genetics, Gustav Wieds Vej 10, Building 3135, DK-8000 Aarhus, Denmark
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40
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Anion translocation through an Slc26 transporter mediates lumen expansion during tubulogenesis. Proc Natl Acad Sci U S A 2013; 110:14972-7. [PMID: 23980138 DOI: 10.1073/pnas.1220884110] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Lumen formation is a critical event in biological tube formation, yet its molecular mechanisms remain poorly understood. Specifically, how lumen expansion is coordinated with other processes of tubulogenesis is not well known, and the role of membrane transporters in tubulogenesis during development has not been adequately addressed. Here we identify a solute carrier 26 (Slc26) family protein as an essential regulator of tubulogenesis using the notochord of the invertebrate chordate Ciona intestinalis as a model. Ci-Slc26aα is indispensable for lumen formation and expansion, but not for apical/luminal membrane formation and lumen connection. Ci-Slc26aα acts as an anion transporter, mediating the electrogenic exchange of sulfate or oxalate for chloride or bicarbonate and electroneutral chloride:bicarbonate exchange. Mutant rescue assays show that this transport activity is essential for Ci-Slc26aα's in vivo function. Our work reveals the consequences and relationships of several key processes in lumen formation, and establishes an in vivo assay for studying the molecular basis of the transport properties of SLC26 family transporters and their related diseases.
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Górska-Andrzejak J. Glia-related circadian plasticity in the visual system of Diptera. Front Physiol 2013; 4:36. [PMID: 23986707 PMCID: PMC3750947 DOI: 10.3389/fphys.2013.00036] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2012] [Accepted: 02/13/2013] [Indexed: 11/28/2022] Open
Abstract
The circadian changes in morphology of the first visual neuropil or lamina of Diptera represent an example of the neuronal plasticity controlled by the circadian clock (circadian plasticity). It is observed in terminals of the compound eye photoreceptor cells, the peripheral oscillators expressing the clock genes. However, it has been found also in their postsynaptic partners, the L1 and L2 monopolar cells, in which the activity of the clock genes have not yet been detected. The circadian input that the L1 and L2 receive seems to originate not only from the retina photoreceptors and from the circadian pacemaker neurons located in the brain, but also from the glial cells that express the clock genes and thus contain circadian oscillators. This paper summarizes the morphological and biochemical rhythms in glia of the optic lobe, shows how they contribute to circadian plasticity, and discusses how glial clocks may modulate circadian rhythms in the lamina.
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Affiliation(s)
- Jolanta Górska-Andrzejak
- Department of Cell Biology and Imaging, Institute of Zoology, Jagiellonian University Kraków, Poland
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42
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Adams DS, Levin M. Endogenous voltage gradients as mediators of cell-cell communication: strategies for investigating bioelectrical signals during pattern formation. Cell Tissue Res 2013; 352:95-122. [PMID: 22350846 PMCID: PMC3869965 DOI: 10.1007/s00441-012-1329-4] [Citation(s) in RCA: 116] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2011] [Accepted: 01/12/2012] [Indexed: 01/07/2023]
Abstract
Alongside the well-known chemical modes of cell-cell communication, we find an important and powerful system of bioelectrical signaling: changes in the resting voltage potential (Vmem) of the plasma membrane driven by ion channels, pumps and gap junctions. Slow Vmem changes in all cells serve as a highly conserved, information-bearing pathway that regulates cell proliferation, migration and differentiation. In embryonic and regenerative pattern formation and in the disorganization of neoplasia, bioelectrical cues serve as mediators of large-scale anatomical polarity, organ identity and positional information. Recent developments have resulted in tools that enable a high-resolution analysis of these biophysical signals and their linkage with upstream and downstream canonical genetic pathways. Here, we provide an overview for the study of bioelectric signaling, focusing on state-of-the-art approaches that use molecular physiology and developmental genetics to probe the roles of bioelectric events functionally. We highlight the logic, strategies and well-developed technologies that any group of researchers can employ to identify and dissect ionic signaling components in their own work and thus to help crack the bioelectric code. The dissection of bioelectric events as instructive signals enabling the orchestration of cell behaviors into large-scale coherent patterning programs will enrich on-going work in diverse areas of biology, as biophysical factors become incorporated into our systems-level understanding of cell interactions.
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Affiliation(s)
- Dany S Adams
- Department of Biology, and Center for Regenerative and Developmental Biology, Tufts University, 200 Boston Ave, Medford, MA 02155, USA
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43
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Irles P, Silva-Torres FA, Piulachs MD. RNAi reveals the key role of Nervana 1 in cockroach oogenesis and embryo development. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2013; 43:178-188. [PMID: 23262289 DOI: 10.1016/j.ibmb.2012.12.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2012] [Revised: 12/07/2012] [Accepted: 12/11/2012] [Indexed: 06/01/2023]
Abstract
Na(+), K(+)-ATPases is a heterodimer protein consisting of α- and β-subunits that control the ion transport through cell membranes. In insects the β-subunit of the Na(+), K(+)-ATPase, known as Nervana, was characterized as a nervous system-specific glycoprotein antigen from adult Drosophila melanogaster heads. Nervana is expressed ubiquitously in all insect tissues, and in epithelial cells appeared located in a basolateral position as part of the septate junctions. Herein we study two Nervana isoforms from Blattella germanica, a cockroach species with panoistic ovaries. The sequencing and the phylogenetic analysis results suggest that these two isoforms are orthologs of D. melanogaster Nervana 1 and Nervana 2, respectively. Nervana 1 is highly expressed in the ovary of B. germanica, and depleting its expression results in changes in oocyte shape that do not impair oviposition. However, the resulting embryos show different defects and never hatch. These findings highlight the importance of this type of membrane pump in insect oogenesis as well as in embryo development, and its possible regulation by juvenile hormone.
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Affiliation(s)
- Paula Irles
- Institut de Biologia Evolutiva (Universitat Pompeu Fabra-CSIC), Passeig Marítim de la Barceloneta, 37, 08003 Barcelona, Spain.
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Cell-type-specific roles of Na+/K+ ATPase subunits in Drosophila auditory mechanosensation. Proc Natl Acad Sci U S A 2012; 110:181-6. [PMID: 23248276 DOI: 10.1073/pnas.1208866110] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Ion homeostasis is a fundamental cellular process particularly important in excitable cell activities such as hearing. It relies on the Na(+)/K(+) ATPase (also referred to as the Na pump), which is composed of a catalytic α subunit and a β subunit required for its transport to the plasma membrane and for regulating its activity. We show that α and β subunits are expressed in Johnston's organ (JO), the Drosophila auditory organ. We knocked down expression of α subunits (ATPα and α-like) and β subunits (nrv1, nrv2, and nrv3) individually in JO with UAS/Gal4-mediated RNAi. ATPα shows elevated expression in the ablumenal membrane of scolopale cells, which enwrap JO neuronal dendrites in endolymph-like compartments. Knocking down ATPα, but not α-like, in the entire JO or only in scolopale cells using specific drivers, resulted in complete deafness. Among β subunits, nrv2 is expressed in scolopale cells and nrv3 in JO neurons. Knocking down nrv2 in scolopale cells blocked Nrv2 expression, reduced ATPα expression in the scolopale cells, and caused almost complete deafness. Furthermore, knockdown of either nrv2 or ATPα specifically in scolopale cells causes abnormal, electron-dense material accumulation in the scolopale space. Similarly, nrv3 functions in JO but not in scolopale cells, suggesting neuron specificity that parallels nrv2 scolopale cell-specific support of the catalytic ATPα. Our studies provide an amenable model to investigate generation of endolymph-like extracellular compartments.
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Marden JH, Fescemyer HW, Schilder RJ, Doerfler WR, Vera JC, Wheat CW. GENETIC VARIATION IN HIF SIGNALING UNDERLIES QUANTITATIVE VARIATION IN PHYSIOLOGICAL AND LIFE-HISTORY TRAITS WITHIN LOWLAND BUTTERFLY POPULATIONS. Evolution 2012; 67:1105-15. [DOI: 10.1111/evo.12004] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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Jaspers MHJ, Nolde K, Behr M, Joo SH, Plessmann U, Nikolov M, Urlaub H, Schuh R. The claudin Megatrachea protein complex. J Biol Chem 2012; 287:36756-65. [PMID: 22930751 DOI: 10.1074/jbc.m112.399410] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Claudins are integral transmembrane components of the tight junctions forming trans-epithelial barriers in many organs, such as the nervous system, lung, and epidermis. In Drosophila three claudins have been identified that are required for forming the tight junctions analogous structure, the septate junctions (SJs). The lack of claudins results in a disruption of SJ integrity leading to a breakdown of the trans-epithelial barrier and to disturbed epithelial morphogenesis. However, little is known about claudin partners for transport mechanisms and membrane organization. Here we present a comprehensive analysis of the claudin proteome in Drosophila by combining biochemical and physiological approaches. Using specific antibodies against the claudin Megatrachea for immunoprecipitation and mass spectrometry, we identified 142 proteins associated with Megatrachea in embryos. The Megatrachea interacting proteins were analyzed in vivo by tissue-specific knockdown of the corresponding genes using RNA interference. We identified known and novel putative SJ components, such as the gene product of CG3921. Furthermore, our data suggest that the control of secretion processes specific to SJs and dependent on Sec61p may involve Megatrachea interaction with Sec61 subunits. Also, our findings suggest that clathrin-coated vesicles may regulate Megatrachea turnover at the plasma membrane similar to human claudins. As claudins are conserved both in structure and function, our findings offer novel candidate proteins involved in the claudin interactome of vertebrates and invertebrates.
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Affiliation(s)
- Martin H J Jaspers
- Research Group Molecular Organogenesis, Max Planck Institute for Biophysical Chemistry, Am Fassberg, 37077 Göttingen, Germany
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Chang JT, Lowery LA, Sive H. Multiple roles for the Na,K-ATPase subunits, Atp1a1 and Fxyd1, during brain ventricle development. Dev Biol 2012; 368:312-22. [PMID: 22683378 DOI: 10.1016/j.ydbio.2012.05.034] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2011] [Revised: 05/29/2012] [Accepted: 05/29/2012] [Indexed: 01/26/2023]
Abstract
Formation of the vertebrate brain ventricles requires both production of cerebrospinal fluid (CSF), and its retention in the ventricles. The Na,K-ATPase is required for brain ventricle development, and we show here that this protein complex impacts three associated processes. The first requires both the alpha subunit (Atp1a1) and the regulatory subunit, Fxyd1, and leads to formation of a cohesive neuroepithelium, with continuous apical junctions. The second process leads to modulation of neuroepithelial permeability, and requires Atp1a1, which increases permeability with partial loss of function and decreases it with overexpression. In contrast, fxyd1 overexpression does not alter neuroepithelial permeability, suggesting that its activity is limited to neuroepithelium formation. RhoA regulates both neuroepithelium formation and permeability, downstream of the Na,K-ATPase. A third process, likely to be CSF production, is RhoA-independent, requiring Atp1a1, but not Fxyd1. Consistent with a role for Na,K-ATPase pump function, the inhibitor ouabain prevents neuroepithelium formation, while intracellular Na(+) increases after Atp1a1 and Fxyd1 loss of function. These data include the first reported role for Fxyd1 in the developing brain, and indicate that the Na,K-ATPase regulates three aspects of brain ventricle development essential for normal function: formation of a cohesive neuroepithelium, restriction of neuroepithelial permeability, and production of CSF.
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Affiliation(s)
- Jessica T Chang
- Whitehead Institute for Biomedical Research, Nine Cambridge Center, Cambridge, MA 02142, United States
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Drosophila Src regulates anisotropic apical surface growth to control epithelial tube size. Nat Cell Biol 2012; 14:518-25. [PMID: 22446737 PMCID: PMC3343215 DOI: 10.1038/ncb2467] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2011] [Accepted: 02/22/2012] [Indexed: 11/08/2022]
Abstract
Networks of epithelial and endothelial tubes are essential for the function of organs such as the lung, kidney and vascular system. The sizes and shapes of these tubes are highly regulated to match their individual functions. Defects in tube size can cause debilitating diseases such as polycystic kidney disease and ischaemia. It is therefore critical to understand how tube dimensions are regulated. Here we identify the tyrosine kinase Src as an instructive regulator of epithelial-tube length in the Drosophila tracheal system. Loss-of-function Src42 mutations shorten tracheal tubes, whereas Src42 overexpression elongates them. Surprisingly, Src42 acts distinctly from known tube-size pathways and regulates both the amount of apical surface growth and, with the conserved formin dDaam, the direction of growth. Quantitative three-dimensional image analysis reveals that Src42- and dDaam-mutant tracheal cells expand more in the circumferential than the axial dimension, resulting in tubes that are shorter in length-but larger in diameter-than wild-type tubes. Thus, Src42 and dDaam control tube dimensions by regulating the direction of anisotropic growth, a mechanism that has not previously been described.
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Wang S, Samakovlis C. Grainy head and its target genes in epithelial morphogenesis and wound healing. Curr Top Dev Biol 2012; 98:35-63. [PMID: 22305158 DOI: 10.1016/b978-0-12-386499-4.00002-1] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The Grainy head (Grh) family of transcription factors is characterized by a unique DNA-binding domain that binds to a conserved consensus sequence. Nematodes and flies have a single grh gene, whereas mice and humans have evolved three genes encoding Grainy head-like (Grhl) factors. We review the biological function of Grh in different animals and the mechanisms modulating its activity. grh and grhl genes play a remarkably conserved role in epithelial organ development and extracellular barrier repair after tissue damage. Recent studies in flies and vertebrates suggest that Grh factors may be primary determinants of cell adhesion and epithelial tissue formation. Grh proteins can dimerize and act as activators or repressors in different developmental contexts. In flies, tissue-specific, alternative splicing generates different Grh isoforms with different DNA-binding specificities and functions. Grh activity is also modulated by receptor tyrosine kinases: it is phosphorylated by extracellular signal regulated kinase, and this phosphorylation is selectively required for epidermal barrier repair. Two mechanisms have been proposed to explain the repressive function of Grh on target gene transcription. First, Grh can target the Polycomb silencing complex to specific response elements. Second, it can directly compete for DNA binding with transcriptional activators. Understanding the molecular mechanisms of gene regulation by Grh factors is likely to elucidate phylogenetically conserved mechanisms of epithelial cell morphogenesis and regeneration upon tissue damage.
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Affiliation(s)
- Shenqiu Wang
- Department of Developmental Biology, Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
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50
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Yanagihashi Y, Usui T, Izumi Y, Yonemura S, Sumida M, Tsukita S, Uemura T, Furuse M. A novel smooth septate junction-associated membrane protein, Snakeskin, is required for intestinal barrier function in Drosophila. J Cell Sci 2012; 125:1980-90. [DOI: 10.1242/jcs.096800] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Septate junctions (SJs) are the membrane specializations observed between epithelial cells in invertebrates. SJs play a crucial role in epithelial barrier function by restricting free diffusion of solutes through the intercellular space. In arthropod species, two morphologically different types of SJs have been described: pleated septate junctions (pSJs) and smooth septate junctions (sSJs), which are specific to ectodermal and endodermal epithelia, respectively. In contrast to the recent understanding of pSJ-related proteins, the molecular constituents of sSJs are mostly unknown. Here we report a novel sSJ-specific membrane protein, designated ‘Snakeskin’ (Ssk). Ssk is highly concentrated in sSJs in the Drosophila midgut and Malpighian tubules. Lack of Ssk expression is embryonically lethal in Drosophila and results in defective sSJ formation accompanied by abnormal morphology of midgut epithelial cells. We also show that the barrier function of the midgut to a fluorescent tracer is impaired in Ssk-knockdown larvae. These results suggest that Ssk is required for the intestinal barrier function in Drosophila.
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