1
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Kimmich MJ, Sundaramurthy S, Geary MA, Lesanpezeshki L, Yingling CV, Vanapalli SA, Littlefield RS, Pruyne D. FHOD-1/profilin-mediated actin assembly protects sarcomeres against contraction-induced deformation in C. elegans. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.29.582848. [PMID: 38559004 PMCID: PMC10979920 DOI: 10.1101/2024.02.29.582848] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
Formin HOmology Domain 2-containing (FHOD) proteins are a subfamily of actin-organizing formins important for striated muscle development in many animals. We showed previously that absence of the sole FHOD protein, FHOD-1, from C. elegans results in thin body-wall muscles with misshapen dense bodies that serve as sarcomere Z-lines. We demonstrate here that actin polymerization by FHOD-1 is required for its function in muscle development, and that FHOD-1 cooperates with profilin PFN-3 for dense body morphogenesis, and profilins PFN-2 and PFN-3 to promote body-wall muscle growth. We further demonstrate dense bodies in fhod-1 and pfn-3 mutants are less stable than in wild type animals, having a higher proportion of dynamic protein, and becoming distorted by prolonged muscle contraction. We also observe accumulation of actin depolymerization factor/cofilin homolog UNC-60B in body-wall muscle of these mutants. Such accumulations may indicate targeted disassembly of thin filaments dislodged from unstable dense bodies, and may account for the abnormally slow growth and reduced strength of body-wall muscle in fhod-1 mutants. Overall, these results show the importance of FHOD protein-mediated actin assembly to forming stable sarcomere Z-lines, and identify profilin as a new contributor to FHOD activity in striated muscle development.
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Affiliation(s)
- Michael J. Kimmich
- Department of Cell and Developmental Biology, State University of New York Upstate Medical University, Syracuse, NY 13210
| | - Sumana Sundaramurthy
- Department of Cell and Developmental Biology, State University of New York Upstate Medical University, Syracuse, NY 13210
| | - Meaghan A. Geary
- Department of Cell and Developmental Biology, State University of New York Upstate Medical University, Syracuse, NY 13210
| | - Leila Lesanpezeshki
- Department of Chemical Engineering, Texas Tech University, Lubbock, TX 79409
| | - Curtis V. Yingling
- Department of Cell and Developmental Biology, State University of New York Upstate Medical University, Syracuse, NY 13210
| | - Siva A. Vanapalli
- Department of Chemical Engineering, Texas Tech University, Lubbock, TX 79409
| | | | - David Pruyne
- Department of Cell and Developmental Biology, State University of New York Upstate Medical University, Syracuse, NY 13210
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2
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Sakai Y, Shimizu T, Tsunekawa M, Hisamoto N, Matsumoto K. Rhotekin regulates axon regeneration through the talin-Vinculin-Vinexin axis in Caenorhabditis elegans. PLoS Genet 2023; 19:e1011089. [PMID: 38150455 PMCID: PMC10752531 DOI: 10.1371/journal.pgen.1011089] [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: 09/25/2023] [Accepted: 12/04/2023] [Indexed: 12/29/2023] Open
Abstract
Axon regeneration requires actomyosin interaction, which generates contractile force and pulls the regenerating axon forward. In Caenorhabditis elegans, TLN-1/talin promotes axon regeneration through multiple down-stream events. One is the activation of the PAT-3/integrin-RHO-1/RhoA GTPase-LET-502/ROCK (Rho-associated coiled-coil kinase)-regulatory non-muscle myosin light-chain (MLC) phosphorylation signaling pathway, which is dependent on the MLC scaffolding protein ALP-1/ALP-Enigma. The other is mediated by the F-actin-binding protein DEB-1/vinculin and is independent of the MLC phosphorylation pathway. In this study, we identified the svh-7/rtkn-1 gene, encoding a homolog of the RhoA-binding protein Rhotekin, as a regulator of axon regeneration in motor neurons. However, we found that RTKN-1 does not function in the RhoA-ROCK-MLC phosphorylation pathway in the regulation of axon regeneration. We show that RTKN-1 interacts with ALP-1 and the vinculin-binding protein SORB-1/vinexin, and that SORB-1 acts with DEB-1 to promote axon regeneration. Thus, RTKN-1 links the DEB-1-SORB-1 complex to ALP-1 and physically connects phosphorylated MLC on ALP-1 to the actin cytoskeleton. These results suggest that TLN-1 signaling pathways coordinate MLC phosphorylation and recruitment of phosphorylated MLC to the actin cytoskeleton during axon regeneration.
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Affiliation(s)
- Yoshiki Sakai
- Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya, Japan
| | - Tatsuhiro Shimizu
- Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya, Japan
| | - Mayuka Tsunekawa
- Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya, Japan
| | - Naoki Hisamoto
- Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya, Japan
| | - Kunihiro Matsumoto
- Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya, Japan
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3
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Serre JM, Slabodnick MM, Goldstein B, Hardin J. SRGP-1/srGAP and AFD-1/afadin stabilize HMP-1/⍺-catenin at rosettes to seal internalization sites following gastrulation in C. elegans. PLoS Genet 2023; 19:e1010507. [PMID: 36867663 PMCID: PMC10016700 DOI: 10.1371/journal.pgen.1010507] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Revised: 03/15/2023] [Accepted: 02/13/2023] [Indexed: 03/04/2023] Open
Abstract
A hallmark of gastrulation is the establishment of germ layers by internalization of cells initially on the exterior. In C. elegans the end of gastrulation is marked by the closure of the ventral cleft, a structure formed as cells internalize during gastrulation, and the subsequent rearrangement of adjacent neuroblasts that remain on the surface. We found that a nonsense allele of srgp-1/srGAP leads to 10-15% cleft closure failure. Deletion of the SRGP-1/srGAP C-terminal domain led to a comparable rate of cleft closure failure, whereas deletion of the N-terminal F-BAR region resulted in milder defects. Loss of the SRGP-1/srGAP C-terminus or F-BAR domain results in defects in rosette formation and defective clustering of HMP-1/⍺-catenin in surface cells during cleft closure. A mutant form of HMP-1/⍺-catenin with an open M domain can suppress cleft closure defects in srgp-1 mutant backgrounds, suggesting that this mutation acts as a gain-of-function allele. Since SRGP-1 binding to HMP-1/⍺-catenin is not favored in this case, we sought another HMP-1 interactor that might be recruited when HMP-1/⍺-catenin is constitutively open. A good candidate is AFD-1/afadin, which genetically interacts with cadherin-based adhesion later during embryonic elongation. AFD-1/afadin is prominently expressed at the vertex of neuroblast rosettes in wildtype, and depletion of AFD-1/afadin increases cleft closure defects in srgp-1/srGAP and hmp-1R551/554A/⍺-catenin backgrounds. We propose that SRGP-1/srGAP promotes nascent junction formation in rosettes; as junctions mature and sustain higher levels of tension, the M domain of HMP-1/⍺-catenin opens, allowing maturing junctions to transition from recruitment of SRGP-1/srGAP to AFD-1/afadin. Our work identifies new roles for ⍺-catenin interactors during a process crucial to metazoan development.
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Affiliation(s)
- Joel M. Serre
- Program in Genetics University of Wisconsin-Madison, Wisconsin, United States of America
| | - Mark M. Slabodnick
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
- Department of Biology, Knox University, Galesburg, Illinois, United States of America
| | - Bob Goldstein
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Jeff Hardin
- Program in Genetics University of Wisconsin-Madison, Wisconsin, United States of America
- Department of Integrative Biology, University of Wisconsin-Madison, Wisconsin, United States of America
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4
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Biswas R, Banerjee A, Lembo S, Zhao Z, Lakshmanan V, Lim R, Le S, Nakasaki M, Kutyavin V, Wright G, Palakodeti D, Ross RS, Jamora C, Vasioukhin V, Jie Y, Raghavan S. Mechanical instability of adherens junctions overrides intrinsic quiescence of hair follicle stem cells. Dev Cell 2021; 56:761-780.e7. [PMID: 33725480 DOI: 10.1016/j.devcel.2021.02.020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Revised: 11/24/2020] [Accepted: 02/18/2021] [Indexed: 12/13/2022]
Abstract
Vinculin, a mechanotransducer associated with both adherens junctions (AJs) and focal adhesions (FAs), plays a central role in force transmission through cell-cell and cell-substratum contacts. We generated the conditional knockout (cKO) of vinculin in murine skin that results in the loss of bulge stem cell (BuSC) quiescence and promotes continual cycling of the hair follicles. Surprisingly, we find that the AJs in vinculin cKO cells are mechanically weak and impaired in force generation despite increased junctional expression of E-cadherin and α-catenin. Mechanistically, we demonstrate that vinculin functions by keeping α-catenin in a stretched/open conformation, which in turn regulates the retention of YAP1, another potent mechanotransducer and regulator of cell proliferation, at the AJs. Altogether, our data provide mechanistic insights into the hitherto-unexplored regulatory link between the mechanical stability of cell junctions and contact-inhibition-mediated maintenance of BuSC quiescence.
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Affiliation(s)
- Ritusree Biswas
- Institute for Stem Cell Science and Regenerative Medicine (inStem), GKVK Campus, Bangalore 560065, India; SASTRA University, Thanjavur, Tamil Nadu 613401, India
| | - Avinanda Banerjee
- Institute for Stem Cell Science and Regenerative Medicine (inStem), GKVK Campus, Bangalore 560065, India; Skin Research Institute of Singapore (A∗STAR), Singapore 138648, Singapore
| | - Sergio Lembo
- Institute for Stem Cell Science and Regenerative Medicine (inStem), GKVK Campus, Bangalore 560065, India
| | - Zhihai Zhao
- Department of Physics, National University of Singapore, Singapore 117542, Singapore
| | - Vairavan Lakshmanan
- Institute for Stem Cell Science and Regenerative Medicine (inStem), GKVK Campus, Bangalore 560065, India; SASTRA University, Thanjavur, Tamil Nadu 613401, India
| | - Ryan Lim
- Skin Research Institute of Singapore (A∗STAR), Singapore 138648, Singapore
| | - Shimin Le
- Department of Physics, National University of Singapore, Singapore 117542, Singapore
| | | | | | - Graham Wright
- A∗STAR Microscopy Platform, Skin Research Institute of Singapore (A∗STAR), Singapore 138648, Singapore
| | - Dasaradhi Palakodeti
- Institute for Stem Cell Science and Regenerative Medicine (inStem), GKVK Campus, Bangalore 560065, India
| | - Robert S Ross
- University of California, San Diego, La Jolla, CA 92093, USA
| | - Colin Jamora
- Institute for Stem Cell Science and Regenerative Medicine (inStem), GKVK Campus, Bangalore 560065, India
| | | | - Yan Jie
- Department of Physics, National University of Singapore, Singapore 117542, Singapore; Mechanobiology Institute, National University of Singapore, Singapore 117411, Singapore
| | - Srikala Raghavan
- Institute for Stem Cell Science and Regenerative Medicine (inStem), GKVK Campus, Bangalore 560065, India; Skin Research Institute of Singapore (A∗STAR), Singapore 138648, Singapore.
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5
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Game of Tissues: How the Epidermis Thrones C. elegans Shape. J Dev Biol 2020; 8:jdb8010007. [PMID: 32182901 PMCID: PMC7151205 DOI: 10.3390/jdb8010007] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Revised: 03/05/2020] [Accepted: 03/06/2020] [Indexed: 12/14/2022] Open
Abstract
The versatility of epithelial cell structure is universally exploited by organisms in multiple contexts. Epithelial cells can establish diverse polarized axes within their tridimensional structure which enables them to flexibly communicate with their neighbors in a 360° range. Hence, these cells are central to multicellularity, and participate in diverse biological processes such as organismal development, growth or immune response and their misfunction ultimately impacts disease. During the development of an organism, the first task epidermal cells must complete is the formation of a continuous sheet, which initiates its own morphogenic process. In this review, we will focus on the C. elegans embryonic epithelial morphogenesis. We will describe how its formation, maturation, and spatial arrangements set the final shape of the nematode C. elegans. Special importance will be given to the tissue-tissue interactions, regulatory tissue-tissue feedback mechanisms and the players orchestrating the process.
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6
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Ono K, Qin Z, Johnsen RC, Baillie DL, Ono S. Kettin, the large actin-binding protein with multiple immunoglobulin domains, is essential for sarcomeric actin assembly and larval development in Caenorhabditis elegans. FEBS J 2019; 287:659-670. [PMID: 31411810 DOI: 10.1111/febs.15039] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Revised: 07/29/2019] [Accepted: 08/12/2019] [Indexed: 12/30/2022]
Abstract
Among many essential genes in the nematode Caenorhabditis elegans, let-330 is located on the left arm of chromosome V and was identified as the largest target of a mutagen in this region. However, let-330 gene has not been characterized at the molecular level. Here, we report that two sequenced let-330 alleles are nonsense mutations of ketn-1, a previously characterized gene encoding kettin. Kettin is a large actin-binding protein of 472 kDa with 31 immunoglobulin domains and is expressed in muscle cells in C. elegans. let-330/ketn-1 mutants are homozygous lethal at the first larval stage with mild defects in body elongation. These mutants have severe defects in sarcomeric actin and myosin assembly in striated muscle. However, α-actinin and vinculin, which are components of the dense bodies anchoring actin to the membranes, were not significantly disorganized by let-330/ketn-1 mutation. Kettin localizes to embryonic myofibrils before α-actinin is expressed, and α-actinin deficiency does not affect kettin localization in larval muscle. Depletion of vinculin minimally affects kettin localization but significantly reduces colocalization of actin with kettin in embryonic muscle cells. These results indicate that kettin is an essential protein for sarcomeric assembly of actin filaments in muscle cells.
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Affiliation(s)
- Kanako Ono
- Department of Pathology, Emory University, Atlanta, GA, USA.,Department of Cell Biology, Emory University, Atlanta, GA, USA.,Winship Cancer Institute, Emory University, Atlanta, GA, USA
| | - Zhaozhao Qin
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, Canada
| | - Robert C Johnsen
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, Canada
| | - David L Baillie
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, Canada
| | - Shoichiro Ono
- Department of Pathology, Emory University, Atlanta, GA, USA.,Department of Cell Biology, Emory University, Atlanta, GA, USA.,Winship Cancer Institute, Emory University, Atlanta, GA, USA
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7
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Shao X, Lucas B, Strauch J, Hardin J. The adhesion modulation domain of Caenorhabditis elegans α-catenin regulates actin binding during morphogenesis. Mol Biol Cell 2019; 30:2115-2123. [PMID: 31188702 PMCID: PMC6743470 DOI: 10.1091/mbc.e19-01-0018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Maintaining tissue integrity during epidermal morphogenesis depends on α-catenin, which connects the cadherin complex to F-actin. We show that the adhesion modulation domain (AMD) of Caenorhabditis elegans HMP-1/α-catenin regulates its F-actin–binding activity and organization of junctional–proximal actin in vivo. Deleting the AMD increases F-actin binding in vitro and leads to excess actin recruitment to adherens junctions in vivo. Reducing actin binding through a compensatory mutation in the C-terminus leads to improved function. Based on the effects of phosphomimetic and nonphosphorylatable mutations, phosphorylation of S509, within the AMD, may regulate F-actin binding. Taken together, these data establish a novel role for the AMD in regulating the actin-binding ability of an α-catenin and its proper function during epithelial morphogenesis.
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Affiliation(s)
- Xiangqiang Shao
- Program in Genetics, University of Wisconsin-Madison, Madison, WI 53706
| | - Bethany Lucas
- Department of Biology, Regis University, Denver, CO 80221
| | - Jared Strauch
- Department of Integrative Biology, University of Wisconsin-Madison, Madison, WI 53706
| | - Jeff Hardin
- Program in Genetics, University of Wisconsin-Madison, Madison, WI 53706.,Department of Integrative Biology, University of Wisconsin-Madison, Madison, WI 53706
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8
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Rohožková J, Hůlková L, Fukalová J, Flachs P, Hozák P. Pairing of homologous chromosomes in C. elegans meiosis requires DEB-1 - an orthologue of mammalian vinculin. Nucleus 2019; 10:93-115. [PMID: 31068058 PMCID: PMC6527391 DOI: 10.1080/19491034.2019.1602337] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
During meiosis, homologous chromosomes undergo a dramatic movement in order to correctly align. This is a critical meiotic event but the molecular properties of this 'chromosomal dance' still remainunclear. We identified DEB-1 - an orthologue of mammalian vinculin - as a new component of the mechanistic modules responsible for attaching the chromosomes to the nuclear envelope as apart of the LINC complex. In early meiotic nuclei of C. elegans, DEB-1 is localized to the nuclear periphery and alongside the synaptonemal complex of paired homologues. Upon DEB-1 depletion, chromosomes attached to SUN-1 foci remain highly motile until late pachytene. Although the initiation of homologue pairing started normally, irregularities in the formation of the synaptonemal complex occur, and these results in meiotic defects such as increased number of univalents at diakinesis and high embryonic lethality. Our data identify DEB-1 as a new player regulating chromosome dynamics and pairing during meiotic prophase I.
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Affiliation(s)
- Jana Rohožková
- a Department of Epigenetics of the Cell Nucleus , Institute of Molecular Genetics AS CR, v.v.i. division BIOCEV , Vestec , Czech Republic
| | - Lenka Hůlková
- a Department of Epigenetics of the Cell Nucleus , Institute of Molecular Genetics AS CR, v.v.i. division BIOCEV , Vestec , Czech Republic
| | - Jana Fukalová
- b Department of Biology of the Cell Nucleus , Institute of Molecular Genetics AS CR, v.v.i. , Prague , Czech Republic
| | - Petr Flachs
- a Department of Epigenetics of the Cell Nucleus , Institute of Molecular Genetics AS CR, v.v.i. division BIOCEV , Vestec , Czech Republic
| | - Pavel Hozák
- a Department of Epigenetics of the Cell Nucleus , Institute of Molecular Genetics AS CR, v.v.i. division BIOCEV , Vestec , Czech Republic.,b Department of Biology of the Cell Nucleus , Institute of Molecular Genetics AS CR, v.v.i. , Prague , Czech Republic.,c Microscopy centre , Institute of Molecular Genetics AS CR, v.v.i. , Prague , Czech Republic
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9
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Pinheiro D, Bellaïche Y. Mechanical Force-Driven Adherens Junction Remodeling and Epithelial Dynamics. Dev Cell 2019; 47:3-19. [PMID: 30300588 DOI: 10.1016/j.devcel.2018.09.014] [Citation(s) in RCA: 111] [Impact Index Per Article: 22.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Revised: 09/02/2018] [Accepted: 09/12/2018] [Indexed: 12/11/2022]
Abstract
During epithelial tissue development, repair, and homeostasis, adherens junctions (AJs) ensure intercellular adhesion and tissue integrity while allowing for cell and tissue dynamics. Mechanical forces play critical roles in AJs' composition and dynamics. Recent findings highlight that beyond a well-established role in reinforcing cell-cell adhesion, AJ mechanosensitivity promotes junctional remodeling and polarization, thereby regulating critical processes such as cell intercalation, division, and collective migration. Here, we provide an integrated view of mechanosensing mechanisms that regulate cell-cell contact composition, geometry, and integrity under tension and highlight pivotal roles for mechanosensitive AJ remodeling in preserving epithelial integrity and sustaining tissue dynamics.
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Affiliation(s)
- Diana Pinheiro
- Institut Curie, PSL Research University, CNRS UMR 3215, INSERM U934, 75248 Paris Cedex 05, France; Sorbonne Universités, UPMC Univ Paris 06, CNRS, CNRS UMR 3215, INSERM U934, 75005 Paris, France
| | - Yohanns Bellaïche
- Institut Curie, PSL Research University, CNRS UMR 3215, INSERM U934, 75248 Paris Cedex 05, France; Sorbonne Universités, UPMC Univ Paris 06, CNRS, CNRS UMR 3215, INSERM U934, 75005 Paris, France.
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10
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Miller PW, Pokutta S, Mitchell JM, Chodaparambil JV, Clarke DN, Nelson WJ, Weis WI, Nichols SA. Analysis of a vinculin homolog in a sponge (phylum Porifera) reveals that vertebrate-like cell adhesions emerged early in animal evolution. J Biol Chem 2018; 293:11674-11686. [PMID: 29880641 PMCID: PMC6066325 DOI: 10.1074/jbc.ra117.001325] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Revised: 05/21/2018] [Indexed: 01/27/2023] Open
Abstract
The evolution of cell-adhesion mechanisms in animals facilitated the assembly of organized multicellular tissues. Studies in traditional animal models have revealed two predominant adhesion structures, the adherens junction (AJ) and focal adhesions (FAs), which are involved in the attachment of neighboring cells to each other and to the secreted extracellular matrix (ECM), respectively. The AJ (containing cadherins and catenins) and FAs (comprising integrins, talin, and paxillin) differ in protein composition, but both junctions contain the actin-binding protein vinculin. The near ubiquity of these structures in animals suggests that AJ and FAs evolved early, possibly coincident with multicellularity. However, a challenge to this perspective is that previous studies of sponges-a divergent animal lineage-indicate that their tissues are organized primarily by an alternative, sponge-specific cell-adhesion mechanism called "aggregation factor." In this study, we examined the structure, biochemical properties, and tissue localization of a vinculin ortholog in the sponge Oscarella pearsei (Op). Our results indicate that Op vinculin localizes to both cell-cell and cell-ECM contacts and has biochemical and structural properties similar to those of vertebrate vinculin. We propose that Op vinculin played a role in cell adhesion and tissue organization in the last common ancestor of sponges and other animals. These findings provide compelling evidence that sponge tissues are indeed organized like epithelia in other animals and support the notion that AJ- and FA-like structures extend to the earliest periods of animal evolution.
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Affiliation(s)
| | - Sabine Pokutta
- From the Departments of Molecular and Cellular Physiology and
- Structural Biology, School of Medicine and
| | - Jennyfer M Mitchell
- the Department of Biological Sciences, University of Denver, Denver, Colorado 80208
| | - Jayanth V Chodaparambil
- From the Departments of Molecular and Cellular Physiology and
- Structural Biology, School of Medicine and
| | - D Nathaniel Clarke
- the Department of Biology, Stanford University, Stanford, California 94305 and
| | - W James Nelson
- From the Departments of Molecular and Cellular Physiology and
- the Department of Biology, Stanford University, Stanford, California 94305 and
| | - William I Weis
- From the Departments of Molecular and Cellular Physiology and
- Structural Biology, School of Medicine and
| | - Scott A Nichols
- the Department of Biological Sciences, University of Denver, Denver, Colorado 80208
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11
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Loveless T, Qadota H, Benian GM, Hardin J. Caenorhabditis elegans SORB-1 localizes to integrin adhesion sites and is required for organization of sarcomeres and mitochondria in myocytes. Mol Biol Cell 2017; 28:3621-3633. [PMID: 28978740 PMCID: PMC5706990 DOI: 10.1091/mbc.e16-06-0455] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Revised: 09/18/2017] [Accepted: 09/25/2017] [Indexed: 01/07/2023] Open
Abstract
We have identified and characterized sorb-1, the only sorbin and SH3 domain-containing protein family member in Caenorhabditis elegans SORB-1 is strongly localized to integrin adhesion complexes in larvae and adults, including adhesion plaques and dense bodies (Z-disks) of striated muscles and attachment plaques of smooth muscles. SORB-1 is recruited to the actin-binding, membrane-distal regions of dense bodies via its C-terminal SH3 domains in an ATN-1(α-actinin)- and ALP-1(ALP/Enigma)-dependent manner, where it contributes to the organization of sarcomeres. SORB-1 is also found in other tissues known to be under mechanical stress, including stress fibers in migratory distal tip cells and the proximal gonad sheath, where it becomes enriched in response to tissue distention. We provide evidence for a novel role for sorbin family proteins: SORB-1 is required for normal positioning of the mitochondrial network in muscle cells. Finally, we demonstrate that SORB-1 interacts directly with two other dense body components, DEB-1(vinculin) and ZYX-1(zyxin). This work establishes SORB-1 as a bona fide sorbin family protein-one of the late additions to the dense body complex and a conserved regulator of body wall muscle sarcomere organization and organelle positioning.
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Affiliation(s)
- Timothy Loveless
- Program in Cellular and Molecular Biology, University of Wisconsin-Madison, Madison, WI 53706
| | - Hiroshi Qadota
- Department of Pathology, Emory University, Atlanta, GA 30322
| | - Guy M Benian
- Department of Pathology, Emory University, Atlanta, GA 30322
| | - Jeff Hardin
- Program in Cellular and Molecular Biology, University of Wisconsin-Madison, Madison, WI 53706
- Department of Integrative Biology, University of Wisconsin-Madison, Madison, WI 53706
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12
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Hu X, Margadant FM, Yao M, Sheetz MP. Molecular stretching modulates mechanosensing pathways. Protein Sci 2017; 26:1337-1351. [PMID: 28474792 DOI: 10.1002/pro.3188] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Revised: 04/26/2017] [Accepted: 04/27/2017] [Indexed: 01/21/2023]
Abstract
For individual cells in tissues to create the diverse forms of biological organisms, it is necessary that they must reliably sense and generate the correct forces over the correct distances and directions. There is considerable evidence that the mechanical aspects of the cellular microenvironment provide critical physical parameters to be sensed. How proteins sense forces and cellular geometry to create the correct morphology is not understood in detail but protein unfolding appears to be a major component in force and displacement sensing. Thus, the crystallographic structure of a protein domain provides only a starting point to then analyze what will be the effects of physiological forces through domain unfolding or catch-bond formation. In this review, we will discuss the recent studies of cytoskeletal and adhesion proteins that describe protein domain dynamics. Forces applied to proteins can activate or inhibit enzymes, increase or decrease protein-protein interactions, activate or inhibit protein substrates, induce catch bonds and regulate interactions with membranes or nucleic acids. Further, the dynamics of stretch-relaxation can average forces or movements to reliably regulate morphogenic movements. In the few cases where single molecule mechanics are studied under physiological conditions such as titin and talin, there are rapid cycles of stretch-relaxation that produce mechanosensing signals. Fortunately, the development of new single molecule and super-resolution imaging methods enable the analysis of single molecule mechanics in physiologically relevant conditions. Thus, we feel that stereotypical changes in cell and tissue shape involve mechanosensing that can be analyzed at the nanometer level to determine the molecular mechanisms involved.
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Affiliation(s)
- Xian Hu
- Mechanobiology Institute, National University of Singapore, Singapore, 117411.,Department of Biosciences, University of Oslo, Oslo, 0316, Norway
| | | | - Mingxi Yao
- Mechanobiology Institute, National University of Singapore, Singapore, 117411
| | - Michael Patrick Sheetz
- Mechanobiology Institute, National University of Singapore, Singapore, 117411.,Department of Biological Sciences, University of Columbia, New York, 10027
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13
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Kang H, Bang I, Jin KS, Lee B, Lee J, Shao X, Heier JA, Kwiatkowski AV, Nelson WJ, Hardin J, Weis WI, Choi HJ. Structural and functional characterization of Caenorhabditis elegans α-catenin reveals constitutive binding to β-catenin and F-actin. J Biol Chem 2017; 292:7077-7086. [PMID: 28298447 PMCID: PMC5409474 DOI: 10.1074/jbc.m116.769778] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Revised: 03/08/2017] [Indexed: 11/06/2022] Open
Abstract
Intercellular epithelial junctions formed by classical cadherins, β-catenin, and the actin-binding protein α-catenin link the actin cytoskeletons of adjacent cells into a structural continuum. These assemblies transmit forces through the tissue and respond to intracellular and extracellular signals. However, the mechanisms of junctional assembly and regulation are poorly understood. Studies of cadherin-catenin assembly in a number of metazoans have revealed both similarities and unexpected differences in the biochemical properties of the cadherin·catenin complex that likely reflect the developmental and environmental requirements of different tissues and organisms. Here, we report the structural and biochemical characterization of HMP-1, the Caenorhabditis elegans α-catenin homolog, and compare it with mammalian α-catenin. HMP-1 shares overall similarity in structure and actin-binding properties, but displayed differences in conformational flexibility and allosteric regulation from mammalian α-catenin. HMP-1 bound filamentous actin with an affinity in the single micromolar range, even when complexed with the β-catenin homolog HMP-2 or when present in a complex of HMP-2 and the cadherin homolog HMR-1, indicating that HMP-1 binding to F-actin is not allosterically regulated by the HMP-2·HMR-1 complex. The middle (i.e. M) domain of HMP-1 appeared to be less conformationally flexible than mammalian α-catenin, which may underlie the dampened effect of HMP-2 binding on HMP-1 actin-binding activity compared with that of the mammalian homolog. In conclusion, our data indicate that HMP-1 constitutively binds β-catenin and F-actin, and although the overall structure and function of HMP-1 and related α-catenins are similar, the vertebrate proteins appear to be under more complex conformational regulation.
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Affiliation(s)
- Hyunook Kang
- From the School of Biological Sciences, Seoul National University, Seoul 08826, South Korea
| | - Injin Bang
- From the School of Biological Sciences, Seoul National University, Seoul 08826, South Korea
| | - Kyeong Sik Jin
- the Pohang Accelerator Laboratory, Pohang, Gyeongbuk 37673, South Korea
| | - Boyun Lee
- the Department of Biophysics and Chemical Biology and
| | - Junho Lee
- From the School of Biological Sciences, Seoul National University, Seoul 08826, South Korea
- the Department of Biophysics and Chemical Biology and
- the Institute of Molecular Biology and Genetics, Seoul National University, Seoul 08826, South Korea
| | - Xiangqiang Shao
- the Department of Zoology and Program in Genetics, University of Wisconsin, Madison, Wisconsin 53706
| | - Jonathon A Heier
- the Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261, and
| | - Adam V Kwiatkowski
- the Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261, and
| | - W James Nelson
- the Departments of Biology
- Molecular and Cellular Physiology, and
| | - Jeff Hardin
- the Department of Zoology and Program in Genetics, University of Wisconsin, Madison, Wisconsin 53706
| | - William I Weis
- Molecular and Cellular Physiology, and
- Structural Biology, Stanford University School of Medicine, Stanford, California 94305
| | - Hee-Jung Choi
- From the School of Biological Sciences, Seoul National University, Seoul 08826, South Korea,
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14
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Balachandran RS, Heighington CS, Starostina NG, Anderson JW, Owen DL, Vasudevan S, Kipreos ET. The ubiquitin ligase CRL2ZYG11 targets cyclin B1 for degradation in a conserved pathway that facilitates mitotic slippage. J Cell Biol 2016; 215:151-166. [PMID: 27810909 PMCID: PMC5084644 DOI: 10.1083/jcb.201601083] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Accepted: 09/22/2016] [Indexed: 12/18/2022] Open
Abstract
Cells arrested in mitosis by inactivation of the APC/C complex sometimes manage to exit mitosis in a process called mitotic slippage, which helps cancer cells circumvent chemotherapy drugs. Balachandran et al. show that mitotic slippage occurs as a result of targeting of cyclin B1 for degradation by the ligase CRL2ZYG11. The anaphase-promoting complex/cyclosome (APC/C) ubiquitin ligase is known to target the degradation of cyclin B1, which is crucial for mitotic progression in animal cells. In this study, we show that the ubiquitin ligase CRL2ZYG-11 redundantly targets the degradation of cyclin B1 in Caenorhabditis elegans and human cells. In C. elegans, both CRL2ZYG-11 and APC/C are required for proper progression through meiotic divisions. In human cells, inactivation of CRL2ZYG11A/B has minimal effects on mitotic progression when APC/C is active. However, when APC/C is inactivated or cyclin B1 is overexpressed, CRL2ZYG11A/B-mediated degradation of cyclin B1 is required for normal progression through metaphase. Mitotic cells arrested by the spindle assembly checkpoint, which inactivates APC/C, often exit mitosis in a process termed “mitotic slippage,” which generates tetraploid cells and limits the effectiveness of antimitotic chemotherapy drugs. We show that ZYG11A/B subunit knockdown, or broad cullin–RING ubiquitin ligase inactivation with the small molecule MLN4924, inhibits mitotic slippage in human cells, suggesting the potential for antimitotic combination therapy.
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Affiliation(s)
| | | | | | - James W Anderson
- Department of Cellular Biology, University of Georgia, Athens, GA 30602
| | - David L Owen
- Department of Cellular Biology, University of Georgia, Athens, GA 30602
| | | | - Edward T Kipreos
- Department of Cellular Biology, University of Georgia, Athens, GA 30602
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15
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Goldmann WH. Role of vinculin in cellular mechanotransduction. Cell Biol Int 2016; 40:241-56. [DOI: 10.1002/cbin.10563] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Accepted: 11/14/2015] [Indexed: 12/17/2022]
Affiliation(s)
- Wolfgang H. Goldmann
- Department of Biophysics; Friedrich-Alexander-University of Erlangen-Nuremberg; Erlangen Germany
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16
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Luck AN, Anderson KG, McClung CM, VerBerkmoes NC, Foster JM, Michalski ML, Slatko BE. Tissue-specific transcriptomics and proteomics of a filarial nematode and its Wolbachia endosymbiont. BMC Genomics 2015; 16:920. [PMID: 26559510 PMCID: PMC4642636 DOI: 10.1186/s12864-015-2083-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2015] [Accepted: 10/15/2015] [Indexed: 11/12/2022] Open
Abstract
Background Filarial nematodes cause debilitating human diseases. While treatable, recent evidence suggests drug resistance is developing, necessitating the development of novel targets and new treatment options. Although transcriptomic and proteomic studies around the nematode life cycle have greatly enhanced our knowledge, whole organism approaches have not provided spatial resolution of gene expression, which can be gained by examining individual tissues. Generally, due to their small size, tissue dissection of human-infecting filarial nematodes remains extremely challenging. However, canine heartworm disease is caused by a closely related and much larger filarial nematode, Dirofilaria immitis. As with many other filarial nematodes, D. immitis contains Wolbachia, an obligate bacterial endosymbiont present in the hypodermis and developing oocytes within the uterus. Here, we describe the first concurrent tissue-specific transcriptomic and proteomic profiling of a filarial nematode (D. immitis) and its Wolbachia (wDi) in order to better understand tissue functions and identify tissue-specific antigens that may be used for the development of new diagnostic and therapeutic tools. Methods Adult D. immitis worms were dissected into female body wall (FBW), female uterus (FU), female intestine (FI), female head (FH), male body wall (MBW), male testis (MT), male intestine (MI), male head (MH) and 10.1186/s12864-015-2083-2 male spicule (MS) and used to prepare transcriptomic and proteomic libraries. Results Transcriptomic and proteomic analysis of several D. immitis tissues identified many biological functions enriched within certain tissues. Hierarchical clustering of the D. immitis tissue transcriptomes, along with the recently published whole-worm adult male and female D. immitis transcriptomes, revealed that the whole-worm transcriptome is typically dominated by transcripts originating from reproductive tissue. The uterus appeared to have the most variable transcriptome, possibly due to age. Although many functions are shared between the reproductive tissues, the most significant differences in gene expression were observed between the uterus and testis. Interestingly, wDi gene expression in the male and female body wall is fairly similar, yet slightly different to that of Wolbachia gene expression in the uterus. Proteomic methods verified 32 % of the predicted D. immitis proteome, including over 700 hypothetical proteins of D. immitis. Of note, hypothetical proteins were among some of the most abundant Wolbachia proteins identified, which may fulfill some important yet still uncharacterized biological function. Conclusions The spatial resolution gained from this parallel transcriptomic and proteomic analysis adds to our understanding of filarial biology and serves as a resource with which to develop future therapeutic strategies against filarial nematodes and their Wolbachia endosymbionts. Electronic supplementary material The online version of this article (doi:10.1186/s12864-015-2083-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Ashley N Luck
- Genome Biology Division, New England Biolabs, Inc., 240 County Road, Ipswich, MA, 01938, USA
| | - Kathryn G Anderson
- Department of Biology and Microbiology, University of Wisconsin Oshkosh, Oshkosh, WI, 54901, USA
| | - Colleen M McClung
- Chemical Biology Division, New England Biolabs, Inc., 240 County Road, Ipswich, MA, 01938, USA
| | - Nathan C VerBerkmoes
- Chemical Biology Division, New England Biolabs, Inc., 240 County Road, Ipswich, MA, 01938, USA
| | - Jeremy M Foster
- Genome Biology Division, New England Biolabs, Inc., 240 County Road, Ipswich, MA, 01938, USA
| | - Michelle L Michalski
- Department of Biology and Microbiology, University of Wisconsin Oshkosh, Oshkosh, WI, 54901, USA
| | - Barton E Slatko
- Genome Biology Division, New England Biolabs, Inc., 240 County Road, Ipswich, MA, 01938, USA.
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17
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Ono S. Regulation of structure and function of sarcomeric actin filaments in striated muscle of the nematode Caenorhabditis elegans. Anat Rec (Hoboken) 2015; 297:1548-59. [PMID: 25125169 DOI: 10.1002/ar.22965] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2014] [Revised: 02/26/2014] [Accepted: 02/26/2014] [Indexed: 02/01/2023]
Abstract
The nematode Caenorhabditis elegans has been used as a valuable system to study structure and function of striated muscle. The body wall muscle of C. elegans is obliquely striated muscle with highly organized sarcomeric assembly of actin, myosin, and other accessory proteins. Genetic and molecular biological studies in C. elegans have identified a number of genes encoding structural and regulatory components for the muscle contractile apparatuses, and many of them have counterparts in mammalian cardiac and skeletal muscles or striated muscles in other invertebrates. Applicability of genetics, cell biology, and biochemistry has made C. elegans an excellent system to study mechanisms of muscle contractility and assembly and maintenance of myofibrils. This review focuses on the regulatory mechanisms of structure and function of actin filaments in the C. elegans body wall muscle. Sarcomeric actin filaments in C. elegans muscle are associated with the troponin-tropomyosin system that regulates the actin-myosin interaction. Proteins that bind to the side and ends of actin filaments support ordered assembly of thin filaments. Furthermore, regulators of actin dynamics play important roles in initial assembly, growth, and maintenance of sarcomeres. The knowledge acquired in C. elegans can serve as bases to understand the basic mechanisms of muscle structure and function.
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Affiliation(s)
- Shoichiro Ono
- Department of Pathology, Emory University, Atlanta, Georgia; Department of Cell Biology, Emory University, Atlanta, Georgia
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18
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Matsunaga Y, Qadota H, Furukawa M, Choe HH, Benian GM. Twitchin kinase interacts with MAPKAP kinase 2 in Caenorhabditis elegans striated muscle. Mol Biol Cell 2015; 26:2096-111. [PMID: 25851606 PMCID: PMC4472019 DOI: 10.1091/mbc.e14-05-1009] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2014] [Accepted: 04/01/2015] [Indexed: 01/13/2023] Open
Abstract
Titin-like giant polypeptides of muscle have protein kinase domains near their C-termini. These kinases are autoinhibited by portions of their own sequences. A putative activator for Caenorhabditis elegans twitchin kinase, MAK-1 (MAPKAP kinase 2), is expressed in nematode striated muscle, partially colocalizes with twitchin in sarcomeres, and binds to and phosphorylates twitchin kinase in vitro. In Caenorhabditis elegans, twitchin is a giant polypeptide located in muscle A-bands. The protein kinase of twitchin is autoinhibited by 45 residues upstream (NL) and 60 residues downstream (CRD) of the kinase catalytic core. Molecular dynamics simulation on a twitchin fragment revealed that the NL is released by pulling force. However, it is unclear how the CRD is removed. To identify proteins that may remove the CRD, we performed a yeast two-hybrid screen using twitchin kinase as bait. One interactor is MAK-1, C. elegans orthologue of MAPKAP kinase 2. MAPKAP kinase 2 is phosphorylated and activated by p38 MAP kinase. We demonstrate that the CRD of twitchin is important for binding to MAK-1. mak-1 is expressed in nematode body wall muscle, and antibodies to MAK-1 localize between and around Z-disk analogues and to the edge of A-bands. Whereas unc-22 mutants are completely resistant, mak-1 mutants are partially resistant to nicotine. MAK-1 can phosphorylate twitchin NL-Kin-CRD in vitro. Genetic data suggest the involvement of two other mak-1 paralogues and two orthologues of p38 MAP kinase. These results suggest that MAK-1 is an activator of twitchin kinase and that the p38 MAP kinase pathway may be involved in the regulation of twitchin.
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Affiliation(s)
- Yohei Matsunaga
- Department of Pathology, Emory University, Atlanta, GA 30322
| | - Hiroshi Qadota
- Department of Pathology, Emory University, Atlanta, GA 30322
| | - Miho Furukawa
- Department of Pathology, Emory University, Atlanta, GA 30322
| | | | - Guy M Benian
- Department of Pathology, Emory University, Atlanta, GA 30322
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19
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Klapholz B, Herbert SL, Wellmann J, Johnson R, Parsons M, Brown NH. Alternative mechanisms for talin to mediate integrin function. Curr Biol 2015; 25:847-57. [PMID: 25754646 PMCID: PMC4386027 DOI: 10.1016/j.cub.2015.01.043] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Revised: 01/19/2015] [Accepted: 01/19/2015] [Indexed: 02/06/2023]
Abstract
Cell-matrix adhesion is essential for building animals, promoting tissue cohesion, and enabling cells to migrate and resist mechanical force. Talin is an intracellular protein that is critical for linking integrin extracellular-matrix receptors to the actin cytoskeleton. A key question raised by structure-function studies is whether talin, which is critical for all integrin-mediated adhesion, acts in the same way in every context. We show that distinct combinations of talin domains are required for each of three different integrin functions during Drosophila development. The partial function of some mutant talins requires vinculin, indicating that recruitment of vinculin allows talin to duplicate its own activities. The different requirements are best explained by alternative mechanisms of talin function, with talin using one or both of its integrin-binding sites. We confirmed these alternatives by showing that the proximity between the second integrin-binding site and integrins differs, suggesting that talin adopts different orientations relative to integrins. Finally, we show that vinculin and actomyosin activity help change talin’s orientation. These findings demonstrate that the mechanism of talin function differs in each developmental context examined. The different arrangements of the talin molecule relative to integrins suggest that talin is able to sense different force vectors, either parallel or perpendicular to the membrane. This provides a paradigm for proteins whose apparent uniform function is in fact achieved by a variety of distinct mechanisms involving different molecular architectures. Integrin function requires distinct sets of talin domains in three different tissues Vinculin helps talin retain function when domains are removed Talin IBS2 is separated from integrins in muscle but not wing adhesion sites Vinculin and actomyosin contribute to separating IBS2 from integrins
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Affiliation(s)
- Benjamin Klapholz
- The Gurdon Institute and Department of Physiology, Development and Neuroscience, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK
| | - Samantha L Herbert
- The Gurdon Institute and Department of Physiology, Development and Neuroscience, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK
| | - Jutta Wellmann
- The Gurdon Institute and Department of Physiology, Development and Neuroscience, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK
| | - Robert Johnson
- The Gurdon Institute and Department of Physiology, Development and Neuroscience, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK
| | - Maddy Parsons
- Randall Division of Cell and Molecular Biophysics, King's College London, London SE1 1UL, UK
| | - Nicholas H Brown
- The Gurdon Institute and Department of Physiology, Development and Neuroscience, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK.
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20
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de la Cruz IP, Ma L, Horvitz HR. The Caenorhabditis elegans iodotyrosine deiodinase ortholog SUP-18 functions through a conserved channel SC-box to regulate the muscle two-pore domain potassium channel SUP-9. PLoS Genet 2014; 10:e1004175. [PMID: 24586202 PMCID: PMC3930498 DOI: 10.1371/journal.pgen.1004175] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2013] [Accepted: 12/28/2013] [Indexed: 02/04/2023] Open
Abstract
Loss-of-function mutations in the Caenorhabditis elegans gene sup-18 suppress the defects in muscle contraction conferred by a gain-of-function mutation in SUP-10, a presumptive regulatory subunit of the SUP-9 two-pore domain K+ channel associated with muscle membranes. We cloned sup-18 and found that it encodes the C. elegans ortholog of mammalian iodotyrosine deiodinase (IYD), an NADH oxidase/flavin reductase that functions in iodine recycling and is important for the biosynthesis of thyroid hormones that regulate metabolism. The FMN-binding site of mammalian IYD is conserved in SUP-18, which appears to require catalytic activity to function. Genetic analyses suggest that SUP-10 can function with SUP-18 to activate SUP-9 through a pathway that is independent of the presumptive SUP-9 regulatory subunit UNC-93. We identified a novel evolutionarily conserved serine-cysteine-rich region in the C-terminal cytoplasmic domain of SUP-9 required for its specific activation by SUP-10 and SUP-18 but not by UNC-93. Since two-pore domain K+ channels regulate the resting membrane potentials of numerous cell types, we suggest that the SUP-18 IYD regulates the activity of the SUP-9 channel using NADH as a coenzyme and thus couples the metabolic state of muscle cells to muscle membrane excitability. Iodotyrosine deiodinase (IYD) controls the recycling of iodide in the biogenesis of thyroid hormones that regulate metabolism. Defects in IYD result in congenital hypothyroidism, a multisystem disorder that can lead to growth failure and severe mental retardation. We identified the gene sup-18 of the nematode Caenorhabditis elegans as a regulator of the SUP-9/UNC-93/SUP-10 two-pore domain potassium channel complex and showed that SUP-18 is an ortholog of IYD, a member of the NADH oxidase/flavin reductase family. SUP-18 IYD is required for the activation of the channel complex by a gain-of-function mutation of the SUP-10 protein. SUP-9 channel activation by SUP-18 requires a conserved serine-cysteine-rich region in the C-terminus of SUP-9 and is independent of the function of the conserved multi-transmembrane protein UNC-93. We propose that SUP-18 uses NADH as a coenzyme to activate the SUP-9 channel in response to the activity of SUP-10 and the metabolic state of muscle cells.
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Affiliation(s)
- Ignacio Perez de la Cruz
- Howard Hughes Medical Institute, Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Long Ma
- State Key Laboratory of Medical Genetics, School of Life Sciences, Central South University, Changsha, Hunan, China
| | - H. Robert Horvitz
- Howard Hughes Medical Institute, Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
- * E-mail:
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21
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Cram EJ. Mechanotransduction in C. elegans morphogenesis and tissue function. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2014; 126:281-316. [PMID: 25081623 DOI: 10.1016/b978-0-12-394624-9.00012-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Mechanobiology is an emerging field that investigates how living cells sense and respond to their physical surroundings. Recent interest in the field has been sparked by the finding that stem cells differentiate along different lineages based on the stiffness of the cell surroundings (Engler et al., 2006), and that metastatic behavior of cancer cells is strongly influenced by the mechanical properties of the surrounding tissue (Kumar and Weaver, 2009). Many questions remain about how cells convert mechanical information, such as viscosity, stiffness of the substrate, or stretch state of the cells, into the biochemical signals that control tissue function. Caenorhabditis elegans researchers are making significant contributions to the understanding of mechanotransduction in vivo. This review summarizes recent insights into the role of mechanical forces in morphogenesis and tissue function. Examples of mechanical regulation across length scales, from the single-celled zygote, to the intercellular coordination that enables cohesive tissue function, to the mechanical influences between tissues, are considered. The power of the C. elegans system as a gene discovery and in vivo quantitative bioimaging platform is enabling an important discoveries in this exciting field.
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Affiliation(s)
- Erin J Cram
- Department of Biology, Northeastern University, Boston, Massachusetts, USA
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22
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Goldmann WH, Auernheimer V, Thievessen I, Fabry B. Vinculin, cell mechanics and tumour cell invasion. Cell Biol Int 2013; 37:397-405. [PMID: 23494917 DOI: 10.1002/cbin.10064] [Citation(s) in RCA: 70] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2012] [Accepted: 01/20/2013] [Indexed: 01/13/2023]
Abstract
The focal adhesion protein, vinculin, is important for transmitting mechanical forces and orchestrating mechanical signalling events. Deregulation of vinculin results in altered cell adhesion, contractility, motility and growth, all of which are important processes in cancer metastasis. This review summarises recent reports on the role of vinculin in cellular force generation and signalling, and discusses implications for a role of vinculin in promoting cancer cell migration in 3D environments.
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Affiliation(s)
- Wolfgang H Goldmann
- Center for Medical Physics and Technology, Biophysics Group, Friedrich-Alexander-University of Erlangen-Nuremberg, Germany.
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23
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Lecroisey C, Brouilly N, Qadota H, Mariol MC, Rochette NC, Martin E, Benian GM, Ségalat L, Mounier N, Gieseler K. ZYX-1, the unique zyxin protein of Caenorhabditis elegans, is involved in dystrophin-dependent muscle degeneration. Mol Biol Cell 2013; 24:1232-49. [PMID: 23427270 PMCID: PMC3623643 DOI: 10.1091/mbc.e12-09-0679] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
In vertebrates, zyxin is a LIM-domain protein belonging to a family composed of seven members. We show that the nematode Caenorhabditis elegans has a unique zyxin-like protein, ZYX-1, which is the orthologue of the vertebrate zyxin subfamily composed of zyxin, migfilin, TRIP6, and LPP. The ZYX-1 protein is expressed in the striated body-wall muscles and localizes at dense bodies/Z-discs and M-lines, as well as in the nucleus. In yeast two-hybrid assays ZYX-1 interacts with several known dense body and M-line proteins, including DEB-1 (vinculin) and ATN-1 (α-actinin). ZYX-1 is mainly localized in the middle region of the dense body/Z-disk, overlapping the apical and basal regions containing, respectively, ATN-1 and DEB-1. The localization and dynamics of ZYX-1 at dense bodies depend on the presence of ATN-1. Fluorescence recovery after photobleaching experiments revealed a high mobility of the ZYX-1 protein within muscle cells, in particular at dense bodies and M-lines, indicating a peripheral and dynamic association of ZYX-1 at these muscle adhesion structures. A portion of the ZYX-1 protein shuttles from the cytoplasm into the nucleus, suggesting a role for ZYX-1 in signal transduction. We provide evidence that the zyx-1 gene encodes two different isoforms, ZYX-1a and ZYX-1b, which exhibit different roles in dystrophin-dependent muscle degeneration occurring in a C. elegans model of Duchenne muscular dystrophy.
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24
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Miller PW, Clarke DN, Weis WI, Lowe CJ, Nelson WJ. The evolutionary origin of epithelial cell-cell adhesion mechanisms. CURRENT TOPICS IN MEMBRANES 2013; 72:267-311. [PMID: 24210433 PMCID: PMC4118598 DOI: 10.1016/b978-0-12-417027-8.00008-8] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
A simple epithelium forms a barrier between the outside and the inside of an organism, and is the first organized multicellular tissue found in evolution. We examine the relationship between the evolution of epithelia and specialized cell-cell adhesion proteins comprising the classical cadherin/β-catenin/α-catenin complex (CCC). A review of the divergent functional properties of the CCC in metazoans and non-metazoans, and an updated phylogenetic coverage of the CCC using recent genomic data reveal: (1) The core CCC likely originated before the last common ancestor of unikonts and their closest bikont sister taxa. (2) Formation of the CCC may have constrained sequence evolution of the classical cadherin cytoplasmic domain and β-catenin in metazoa. (3) The α-catenin-binding domain in β-catenin appears to be the favored mutation site for disrupting β-catenin function in the CCC. (4) The ancestral function of the α/β-catenin heterodimer appears to be an actin-binding module. In some metazoan groups, more complex functions of α-catenin were gained by sequence divergence in the non-actin-binding (N-, M-) domains. (5) Allosteric regulation of α-catenin may have evolved for more complex regulation of the actin cytoskeleton.
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Affiliation(s)
- Phillip W. Miller
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305
| | | | - William I. Weis
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305
| | | | - W. James Nelson
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305
- Department of Biology, Stanford University, Stanford, CA 94305
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25
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Cadherins and their partners in the nematode worm Caenorhabditis elegans. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2013; 116:239-62. [PMID: 23481198 DOI: 10.1016/b978-0-12-394311-8.00011-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The extreme simplicity of Caenorhabditis elegans makes it an ideal system to study the basic principles of cadherin function at the level of single cells within the physiologically relevant context of a developing animal. The genetic tractability of C. elegans also means that components of cadherin complexes can be identified through genetic modifier screens, allowing a comprehensive in vivo characterization of the macromolecular assemblies involved in cadherin function during tissue formation and maintenance in C. elegans. This work shows that a single cadherin system, the classical cadherin-catenin complex, is essential for diverse morphogenetic events during embryogenesis through its interactions with a range of mostly conserved proteins that act to modulate its function. The role of other members of the cadherin family in C. elegans, including members of the Fat-like, Flamingo/CELSR and calsyntenin families is less well characterized, but they have clear roles in neuronal development and function.
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Maiden SL, Harrison N, Keegan J, Cain B, Lynch AM, Pettitt J, Hardin J. Specific conserved C-terminal amino acids of Caenorhabditis elegans HMP-1/α-catenin modulate F-actin binding independently of vinculin. J Biol Chem 2012; 288:5694-706. [PMID: 23271732 DOI: 10.1074/jbc.m112.438093] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Stable intercellular adhesions formed through the cadherin-catenin complex are important determinants of proper tissue architecture and help maintain tissue integrity during morphogenetic movements in developing embryos. A key regulator of this stability is α-catenin, which connects the cadherin-catenin complex to the actin cytoskeleton. Although the C-terminal F-actin-binding domain of α-catenin has been shown to be crucial for its function, a more detailed in vivo analysis of discrete regions and residues required for actin binding has not been performed. Using Caenorhabditis elegans as a model system, we have characterized mutations in hmp-1/α-catenin that identify HMP-1 residues 687-742 and 826-927, as well as amino acid 802, as critical to the localization of junctional proximal actin during epidermal morphogenesis. We also find that the S823F transition in a hypomorphic allele, hmp-1(fe4), decreases actin binding in vitro. Using hmp-1(fe4) animals in a mutagenesis screen, we were then able to identify 11 intragenic suppressors of hmp-1(fe4) that revert actin binding to wild-type levels. Using homology modeling, we show that these amino acids are positioned at key conserved sites within predicted α-helices in the C terminus. Through the use of transgenic animals, we also demonstrate that HMP-1 residues 315-494, which correspond to a putative mechanotransduction domain that binds vinculin in vertebrate αE-catenin, are not required during epidermal morphogenesis but may aid efficient recruitment of HMP-1 to the junction. Our studies are the first to identify key conserved amino acids in the C terminus of α-catenin that modulate F-actin binding in living embryos of a simple metazoan.
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Affiliation(s)
- Stephanie L Maiden
- Department of Zoology, University of Wisconsin, Madison, Wisconsin 53706, USA
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Genetic interactions between UNC-17/VAChT and a novel transmembrane protein in Caenorhabditis elegans. Genetics 2012; 192:1315-25. [PMID: 23051648 DOI: 10.1534/genetics.112.145771] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The unc-17 gene encodes the vesicular acetylcholine transporter (VAChT) in Caenorhabditis elegans. unc-17 reduction-of-function mutants are small, slow growing, and uncoordinated. Several independent unc-17 alleles are associated with a glycine-to-arginine substitution (G347R), which introduces a positive charge in the ninth transmembrane domain (TMD) of UNC-17. To identify proteins that interact with UNC-17/VAChT, we screened for mutations that suppress the uncoordinated phenotype of UNC-17(G347R) mutants. We identified several dominant allele-specific suppressors, including mutations in the sup-1 locus. The sup-1 gene encodes a single-pass transmembrane protein that is expressed in a subset of neurons and in body muscles. Two independent suppressor alleles of sup-1 are associated with a glycine-to-glutamic acid substitution (G84E), resulting in a negative charge in the SUP-1 TMD. A sup-1 null mutant has no obvious deficits in cholinergic neurotransmission and does not suppress unc-17 mutant phenotypes. Bimolecular fluorescence complementation (BiFC) analysis demonstrated close association of SUP-1 and UNC-17 in synapse-rich regions of the cholinergic nervous system, including the nerve ring and dorsal nerve cords. These observations suggest that UNC-17 and SUP-1 are in close proximity at synapses. We propose that electrostatic interactions between the UNC-17(G347R) and SUP-1(G84E) TMDs alter the conformation of the mutant UNC-17 protein, thereby restoring UNC-17 function; this is similar to the interaction between UNC-17/VAChT and synaptobrevin.
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Mi-Mi L, Votra S, Kemphues K, Bretscher A, Pruyne D. Z-line formins promote contractile lattice growth and maintenance in striated muscles of C. elegans. ACTA ACUST UNITED AC 2012; 198:87-102. [PMID: 22753896 PMCID: PMC3392944 DOI: 10.1083/jcb.201202053] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Muscle contraction depends on interactions between actin and myosin filaments organized into sarcomeres, but the mechanism by which actin filaments incorporate into sarcomeres remains unclear. We have found that, during larval development in Caenorhabditis elegans, two members of the actin-assembling formin family, CYK-1 and FHOD-1, are present in striated body wall muscles near or on sarcomere Z lines, where barbed ends of actin filaments are anchored. Depletion of either formin during this period stunted growth of the striated contractile lattice, whereas their simultaneous reduction profoundly diminished lattice size and number of striations per muscle cell. CYK-1 persisted at Z lines in adulthood, and its near complete depletion from adults triggered phenotypes ranging from partial loss of Z line-associated filamentous actin to collapse of the contractile lattice. These results are, to our knowledge, the first genetic evidence implicating sarcomere-associated formins in the in vivo organization of the muscle cytoskeleton.
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Affiliation(s)
- Lei Mi-Mi
- Department of Cell and Developmental Biology, State University of NY Upstate Medical University, Syracuse, NY 13210, USA
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Kukday SS, Manandhar SP, Ludley MC, Burriss ME, Alper BJ, Schmidt WK. Cell-permeable, small-molecule activators of the insulin-degrading enzyme. ACTA ACUST UNITED AC 2012; 17:1348-61. [PMID: 22740246 DOI: 10.1177/1087057112451921] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The insulin-degrading enzyme (IDE) cleaves numerous small peptides, including biologically active hormones and disease-related peptides. The propensity of IDE to degrade neurotoxic Aβ peptides marks IDE as a potential therapeutic target for Alzheimer disease. Using a synthetic reporter based on the yeast a-factor mating pheromone precursor, which is cleaved by multiple IDE orthologs, we identified seven small molecules that stimulate rat IDE activity in vitro. Half-maximal activation of IDE by the compounds is observed in vitro in the range of 43 to 198 µM. All compounds decrease the K(m) of IDE. Four compounds activate IDE in the presence of the competing substrate insulin, which disproportionately inhibits IDE activity. Two compounds stimulate rat IDE activity in a cell-based assay, indicating that they are cell permeable. The compounds demonstrate specificity for rat IDE since they do not enhance the activities of IDE orthologs, including human IDE, and they appear specific for a-factor-based reporters since they do not enhance rat IDE-mediated cleavage of Aβ-based reporters. Our results suggest that IDE activators function in the context of specific enzyme-substrate pairs, indicating that the choice of substrate must be considered in addition to target validation in IDE activator screens.
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Liu Q, Jones TI, Bachmann RA, Meghpara M, Rogowski L, Williams BD, Jones PL. C. elegans PAT-9 is a nuclear zinc finger protein critical for the assembly of muscle attachments. Cell Biosci 2012; 2:18. [PMID: 22616817 PMCID: PMC3419604 DOI: 10.1186/2045-3701-2-18] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2012] [Accepted: 05/22/2012] [Indexed: 11/28/2022] Open
Abstract
Background Caenorhabditis elegans sarcomeres have been studied extensively utilizing both forward and reverse genetic techniques to provide insight into muscle development and the mechanisms behind muscle contraction. A previous genetic screen investigating early muscle development produced 13 independent mutant genes exhibiting a Pat (paralyzed and arrested elongation at the two-fold length of embryonic development) muscle phenotype. This study reports the identification and characterization of one of those genes, pat-9. Results Positional cloning, reverse genetics, and plasmid rescue experiments were used to identify the predicted C. elegans gene T27B1.2 (recently named ztf-19) as the pat-9 gene. Analysis of pat-9 showed it is expressed early in development and within body wall muscle lineages, consistent with a role in muscle development and producing a Pat phenotype. However, unlike most of the other known Pat gene family members, which encode structural components of muscle attachment sites, PAT-9 is an exclusively nuclear protein. Analysis of the predicted PAT-9 amino acid sequence identified one putative nuclear localization domain and three C2H2 zinc finger domains. Both immunocytochemistry and PAT-9::GFP fusion expression confirm that PAT-9 is primarily a nuclear protein and chromatin immunoprecipitation (ChIP) experiments showed that PAT-9 is present on certain gene promoters. Conclusions We have shown that the T27B1.2 gene is pat-9. Considering the Pat-9 mutant phenotype shows severely disrupted muscle attachment sites despite PAT-9 being a nuclear zinc finger protein and not a structural component of muscle attachment sites, we propose that PAT-9 likely functions in the regulation of gene expression for some necessary structural or regulatory component(s) of the muscle attachment sites.
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Affiliation(s)
- Qian Liu
- Department of Cell and Developmental Biology, University of Illinois at Urbana-Champaign, 601 S, Goodwin Ave, B107 Chemical and Life Sciences Laboratory, Urbana, IL, 61801, USA.
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Abstract
Cadherin-based intercellular adhesions are important determinants of proper tissue architecture. These adhesions must be both stable and dynamic to maintain tissue integrity as cells undergo morphogenetic movements during development. The role of α-catenin in this process has been vigorously debated due to conflicting in vitro and in vivo evidence regarding its molecular mechanism of action. Recent data supports the classical view that α-catenin facilitates actin attachments at adherens junctions, but also suggests that α-catenin may act as a force transducer, and may have additional roles in the cytoplasm. These multiple functions for α-catenin converge on the regulation of adhesion and may help to explain its stable yet dynamic nature.
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Affiliation(s)
- Stephanie L Maiden
- Molecular and Cellular Pharmacology Program and Department of Zoology, University of Wisconsin-Madison, Madison, WI 53706, USA
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Warner A, Qadota H, Benian GM, Vogl AW, Moerman DG. The Caenorhabditis elegans paxillin orthologue, PXL-1, is required for pharyngeal muscle contraction and for viability. Mol Biol Cell 2011; 22:2551-63. [PMID: 21633109 PMCID: PMC3135480 DOI: 10.1091/mbc.e10-12-0941] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Caenorhabditis elegans pxl-1 is the orthologue of vertebrate paxillin and is expressed in body wall and pharyngeal muscle. In body wall muscle PXL-1 localizes to dense bodies, M-lines, and adhesion plaques, and in pharyngeal muscle PXL-1 localizes to podosome-like actin attachment complexes. PXL-1 is required in the pharynx for muscle contraction and viability. We have identified the gene C28H8.6 (pxl-1) as the Caenorhabditis elegans orthologue of vertebrate paxillin. PXL-1 contains the four C-terminal LIM domains conserved in paxillin across all species and three of the five LD motifs found in the N-terminal half of most paxillins. In body wall muscle, PXL-1 antibodies and a full-length green fluorescent protein translational fusion localize to adhesion sites in the sarcomere, the functional repeat unit in muscle responsible for contraction. PXL-1 also localizes to ring-shaped structures near the sarcolemma in pharyngeal muscle corresponding to podosome-like sites of actin attachment. Our analysis of a loss-of-function allele of pxl-1, ok1483, shows that loss of paxillin leads to early larval arrested animals with paralyzed pharyngeal muscles and eventual lethality, presumably due to an inability to feed. We rescued the mutant phenotype by expressing paxillin solely in the pharynx and found that these animals survived and are essentially wild type in movement and body wall muscle structure. This indicates a differential requirement for paxillin in these two types of muscle. In pharyngeal muscle it is essential for contraction, whereas in body wall muscle it is dispensable for filament assembly, sarcomere stability, and ultimately movement.
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Affiliation(s)
- Adam Warner
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada
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Moulder GL, Cremona GH, Duerr J, Stirman JN, Fields SD, Martin W, Qadota H, Benian GM, Lu H, Barstead RJ. α-actinin is required for the proper assembly of Z-disk/focal-adhesion-like structures and for efficient locomotion in Caenorhabditis elegans. J Mol Biol 2010; 403:516-28. [PMID: 20850453 PMCID: PMC3440862 DOI: 10.1016/j.jmb.2010.08.055] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2010] [Revised: 08/10/2010] [Accepted: 08/30/2010] [Indexed: 11/22/2022]
Abstract
The actin binding protein α-actinin is a major component of focal adhesions found in vertebrate cells and of focal-adhesion-like structures found in the body wall muscle of the nematode Caenorhabditis elegans. To study its in vivo function in this genetic model system, we isolated a strain carrying a deletion of the single C. elegans α-actinin gene. We assessed the cytological organization of other C. elegans focal adhesion proteins and the ultrastructure of the mutant. The mutant does not have normal dense bodies, as observed by electron microscopy; however, these dense-body-like structures still contain the focal adhesion proteins integrin, talin, and vinculin, as observed by immunofluorescence microscopy. Actin is found in normal-appearing I-bands, but with abnormal accumulations near muscle cell membranes. Although swimming in water appeared grossly normal, use of automated methods for tracking the locomotion of individual worms revealed a defect in bending. We propose that the reduced motility of α-actinin null is due to abnormal dense bodies that are less able to transmit the forces generated by actin/myosin interactions.
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Affiliation(s)
- Gary L. Moulder
- Department of Molecular and Cell Biology, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma 73104
| | - Gina H. Cremona
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0100
| | - Janet Duerr
- Department of Molecular and Cell Biology, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma 73104
| | - Jeffrey N. Stirman
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0100
| | - Stephen D. Fields
- Department of Molecular and Cell Biology, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma 73104
| | - Wendy Martin
- Department of Molecular and Cell Biology, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma 73104
| | - Hiroshi Qadota
- Department of Pathology, Emory University, Atlanta, Georgia 30322
| | - Guy M. Benian
- Department of Pathology, Emory University, Atlanta, Georgia 30322
| | - Hang Lu
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0100
| | - Robert J. Barstead
- Department of Molecular and Cell Biology, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma 73104
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Abraham LS, Oh HJ, Sancar F, Richmond JE, Kim H. An alpha-catulin homologue controls neuromuscular function through localization of the dystrophin complex and BK channels in Caenorhabditis elegans. PLoS Genet 2010; 6. [PMID: 20865173 PMCID: PMC2928805 DOI: 10.1371/journal.pgen.1001077] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2010] [Accepted: 07/21/2010] [Indexed: 11/25/2022] Open
Abstract
The large conductance, voltage- and calcium-dependent potassium (BK) channel serves as a major negative feedback regulator of calcium-mediated physiological processes and has been implicated in muscle dysfunction and neurological disorders. In addition to membrane depolarization, activation of the BK channel requires a rise in cytosolic calcium. Localization of the BK channel near calcium channels is therefore critical for its function. In a genetic screen designed to isolate novel regulators of the Caenorhabditis elegans BK channel, SLO-1, we identified ctn-1, which encodes an α-catulin homologue with homology to the cytoskeletal proteins α-catenin and vinculin. ctn-1 mutants resemble slo-1 loss-of-function mutants, as well as mutants with a compromised dystrophin complex. We determined that CTN-1 uses two distinct mechanisms to localize SLO-1 in muscles and neurons. In muscles, CTN-1 utilizes the dystrophin complex to localize SLO-1 channels near L-type calcium channels. In neurons, CTN-1 is involved in localizing SLO-1 to a specific domain independent of the dystrophin complex. Our results demonstrate that CTN-1 ensures the localization of SLO-1 within calcium nanodomains, thereby playing a crucial role in muscles and neurons. Calcium ions are essential for many physiological processes, including neurosecretion and neuronal and muscle excitation. Paradoxically, abnormal accumulation of calcium ions is associated with cell death and has been documented as an early event in muscle and neural degenerative diseases. One mechanism to avoid detrimental calcium accumulation is to link the calcium increase with activation of calcium-dependent potassium ion channels, thereby reducing cell excitability and preventing further calcium influx. This negative feedback requires these potassium channels to be localized in close proximity to sites of calcium entry. In a Caenorhabditis elegans genetic screen, we identified α-catulin, known as a cytoskeletal regulatory protein in mammals, important for the localization of calcium-dependent potassium channels in both muscles and neurons. In muscle, α-catulin controls the localization of the dystrophin complex, a multimeric protein complex implicated in muscular dystrophy. The dystrophin complex in turn tethers the calcium-dependent potassium channels near calcium channels. In neurons, the α-catulin-mediated localization of the potassium channels is independent of the dystrophin complex. Lack of α-catulin results in mislocalization of the potassium channels, and in turn causes defects in neuromuscular function. Our results support the idea that cytoskeletal proteins function as anchor molecules that localize ion channels to specific cellular domains.
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Affiliation(s)
- Linu S. Abraham
- Department of Cell Biology and Anatomy, The Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, Illinois, United States of America
| | - Hyun J. Oh
- Department of Cell Biology and Anatomy, The Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, Illinois, United States of America
| | - Feyza Sancar
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, Illinois, United States of America
| | - Janet E. Richmond
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, Illinois, United States of America
| | - Hongkyun Kim
- Department of Cell Biology and Anatomy, The Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, Illinois, United States of America
- * E-mail:
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α-Catulin CTN-1 is required for BK channel subcellular localization in C. elegans body-wall muscle cells. EMBO J 2010; 29:3184-95. [PMID: 20700105 DOI: 10.1038/emboj.2010.194] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2010] [Accepted: 07/20/2010] [Indexed: 11/09/2022] Open
Abstract
The BK channel, a voltage- and Ca(2+)-gated large-conductance potassium channel with many important functions, is often localized at specific subcellular domains. Although proper subcellular localization is likely a prerequisite for the channel to perform its physiological functions, little is known about the molecular basis of localization. Here, we show that CTN-1, a homologue of mammalian α-catulin, is required for subcellular localization of SLO-1, the Caenorhabditis elegans BK channel α-subunit, in body-wall muscle cells. CTN-1 was identified in a genetic screen for mutants that suppressed a lethargic phenotype caused by expressing a gain-of-function (gf) isoform of SLO-1. In body-wall muscle cells, CTN-1 coclusters with SLO-1 at regions of dense bodies, which are Z-disk analogs of mammalian skeletal muscle. In ctn-1 loss-of-function (lf) mutants, SLO-1 was mislocalized in body-wall muscle but its transcription and protein level were unchanged. Targeted rescue of ctn-1(lf) in muscle was sufficient to reinstate the lethargic phenotype in slo-1(gf);ctn-1(lf). These results suggest that CTN-1 plays an important role in BK channel function by mediating channel subcellular localization.
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Carisey A, Ballestrem C. Vinculin, an adapter protein in control of cell adhesion signalling. Eur J Cell Biol 2010; 90:157-63. [PMID: 20655620 PMCID: PMC3526775 DOI: 10.1016/j.ejcb.2010.06.007] [Citation(s) in RCA: 204] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2010] [Revised: 06/21/2010] [Accepted: 06/23/2010] [Indexed: 01/09/2023] Open
Abstract
Vinculin, discovered in 1979 (Geiger, 1979), is an adapter protein with binding sites for more than 15 proteins. Biochemical and structural analyses have contributed to detailed knowledge about potential binding partners and the understanding of how their binding may be regulated. Despite all this information the molecular basis of how vinculin acts in cells and controls a wide variety of signals remains elusive. This review aims to highlight recent discoveries with an emphasis on how vinculin is involved in the coordination of a network of signals.
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Affiliation(s)
- Alex Carisey
- Wellcome Trust Centre for Cell-Matrix Research, Faculty of Life Sciences, University of Manchester, Manchester, M13 9PT, UK
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Molecular structure of sarcomere-to-membrane attachment at M-Lines in C. elegans muscle. J Biomed Biotechnol 2010; 2010:864749. [PMID: 20414365 PMCID: PMC2857872 DOI: 10.1155/2010/864749] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2009] [Accepted: 01/30/2010] [Indexed: 01/09/2023] Open
Abstract
C. elegans is an excellent model for studying nonmuscle cell focal adhesions and the analogous muscle cell attachment structures. In the major striated muscle of this nematode, all of the M-lines and the Z-disk analogs (dense bodies) are attached to the muscle cell membrane and underlying extracellular matrix. Accumulating at these sites are many proteins associated with integrin. We have found that nematode M-lines contain a set of protein complexes that link integrin-associated proteins to myosin thick filaments. We have also obtained evidence for intriguing additional functions for these muscle cell attachment proteins.
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Hunter JW, Mullen GP, McManus JR, Heatherly JM, Duke A, Rand JB. Neuroligin-deficient mutants of C. elegans have sensory processing deficits and are hypersensitive to oxidative stress and mercury toxicity. Dis Model Mech 2010; 3:366-76. [PMID: 20083577 DOI: 10.1242/dmm.003442] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Neuroligins are postsynaptic cell adhesion proteins that bind specifically to presynaptic membrane proteins called neurexins. Mutations in human neuroligin genes are associated with autism spectrum disorders in some families. The nematode Caenorhabditis elegans has a single neuroligin gene (nlg-1), and approximately a sixth of C. elegans neurons, including some sensory neurons, interneurons and a subset of cholinergic motor neurons, express a neuroligin transcriptional reporter. Neuroligin-deficient mutants of C. elegans are viable, and they do not appear deficient in any major motor functions. However, neuroligin mutants are defective in a subset of sensory behaviors and sensory processing, and are hypersensitive to oxidative stress and mercury compounds; the behavioral deficits are strikingly similar to traits frequently associated with autism spectrum disorders. Our results suggest a possible link between genetic defects in synapse formation or function, and sensitivity to environmental factors in the development of autism spectrum disorders.
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Affiliation(s)
- Jerrod W Hunter
- Genetic Models of Disease Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA
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39
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The Role of Vinculin in the Regulation of the Mechanical Properties of Cells. Cell Biochem Biophys 2009; 53:115-26. [DOI: 10.1007/s12013-009-9047-6] [Citation(s) in RCA: 98] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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40
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Caenorhabditis elegans galectins LEC-1–LEC-11: Structural features and sugar-binding properties. Biochim Biophys Acta Gen Subj 2008; 1780:1131-42. [DOI: 10.1016/j.bbagen.2008.07.003] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2008] [Revised: 06/28/2008] [Accepted: 07/07/2008] [Indexed: 11/21/2022]
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Woo WM, Berry E, Hudson ML, Swale RE, Goncharov A, Chisholm AD. The C. elegans F-spondin family protein SPON-1 maintains cell adhesion in neural and non-neural tissues. Development 2008; 135:2747-2756. [PMID: 18614580 DOI: 10.1242/dev.015289] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The F-spondin family of extracellular matrix proteins has been implicated in axon outgrowth, fasciculation and neuronal cell migration, as well as in the differentiation and proliferation of non-neuronal cells. In screens for mutants defective in C. elegans embryonic morphogenesis, we identified SPON-1, the only C. elegans member of the spondin family. SPON-1 is synthesized in body muscles and localizes to integrin-containing structures on body muscles and to other basement membranes. SPON-1 maintains strong attachments of muscles to epidermis; in the absence of SPON-1, muscles progressively detach from the epidermis, causing defective epidermal elongation. In animals with reduced integrin function, SPON-1 becomes dose dependent, suggesting that SPON-1 and integrins function in concert to promote the attachment of muscles to the basement membrane. Although spon-1 mutants display largely normal neurite outgrowth, spon-1 synergizes with outgrowth defective mutants, revealing a cryptic role for SPON-1 in axon extension. In motoneurons, SPON-1 acts in axon guidance and fasciculation, whereas in interneurons SPON-1 maintains process position. Our results show that a spondin maintains cell-matrix adhesion in multiple tissues.
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Affiliation(s)
- Wei-Meng Woo
- Department of Molecular, Cell, and Developmental Biology, Sinsheimer Laboratories, University of California, Santa Cruz, CA 95064
| | - Emily Berry
- Department of Molecular, Cell, and Developmental Biology, Sinsheimer Laboratories, University of California, Santa Cruz, CA 95064.,Division of Biological Sciences, University of California San Diego, La Jolla, CA 92093
| | - Martin L Hudson
- Department of Molecular, Cell, and Developmental Biology, Sinsheimer Laboratories, University of California, Santa Cruz, CA 95064
| | - Ryann E Swale
- Department of Molecular, Cell, and Developmental Biology, Sinsheimer Laboratories, University of California, Santa Cruz, CA 95064
| | - Alexandr Goncharov
- Division of Biological Sciences, University of California San Diego, La Jolla, CA 92093.,Howard Hughes Medical Institute
| | - Andrew D Chisholm
- Division of Biological Sciences, University of California San Diego, La Jolla, CA 92093
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Caenorhabditis elegans genes required for the engulfment of apoptotic corpses function in the cytotoxic cell deaths induced by mutations in lin-24 and lin-33. Genetics 2008; 179:403-17. [PMID: 18458102 DOI: 10.1534/genetics.108.087221] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Two types of cell death have been studied extensively in Caenorhabditis elegans, programmed cell death and necrosis. We describe a novel type of cell death that occurs in animals containing mutations in either of two genes, lin-24 and lin-33. Gain-of-function mutations in lin-24 and lin-33 cause the inappropriate deaths of many of the Pn.p hypodermal blast cells and prevent the surviving Pn.p cells from expressing their normal developmental fates. The abnormal Pn.p cells in lin-24 and lin-33 mutant animals are morphologically distinct from the dying cells characteristic of C. elegans programmed cell deaths and necrotic cell deaths. lin-24 encodes a protein with homology to bacterial toxins. lin-33 encodes a novel protein. The cytotoxicity caused by mutation of either gene requires the function of the other. An evolutionarily conserved set of genes required for the efficient engulfment and removal of both apoptotic and necrotic cell corpses is required for the full cell-killing effect of mutant lin-24 and lin-33 genes, suggesting that engulfment promotes these cytotoxic cell deaths.
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Ono K, Yu R, Ono S. Structural components of the nonstriated contractile apparatuses in the Caenorhabditis elegans gonadal myoepithelial sheath and their essential roles for ovulation. Dev Dyn 2007; 236:1093-105. [PMID: 17326220 PMCID: PMC1994093 DOI: 10.1002/dvdy.21091] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Ovulation in the nematode Caenorhabditis elegans is regulated by complex signal transduction pathways and cell-cell interactions. Myoepithelial sheath cells of the proximal ovary are smooth muscle-like cells that provide contractile forces to push a mature oocyte into the spermatheca for fertilization. Although several genes that regulate sheath contraction have been characterized, basic components of the contractile apparatuses of the myoepithelial sheath have not been extensively studied. We identified major structural proteins of the contractile apparatuses of the myoepithelial sheath and characterized their nonstriated arrangement. Of interest, integrin and perlecan were found only at the dense bodies, whereas they localized to both dense bodies and M-lines in the striated body wall muscle. RNA interference of most of the myofibrillar components impaired ovulation in a soma-specific manner. Our results provide basic information that helps understanding the mechanism of sheath contraction during ovulation and establishing a new model to study morphogenesis of nonstriated muscle.
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Affiliation(s)
| | | | - Shoichiro Ono
- Correspondence to: Shoichiro Ono, Department of Pathology, Emory University, 615 Michael Street, Whitehead Research Building, Room 105N, Atlanta, GA 30322. E-mail:
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Mullen GP, Mathews EA, Vu MH, Hunter JW, Frisby DL, Duke A, Grundahl K, Osborne JD, Crowell JA, Rand JB. Choline transport and de novo choline synthesis support acetylcholine biosynthesis in Caenorhabditis elegans cholinergic neurons. Genetics 2007; 177:195-204. [PMID: 17603106 PMCID: PMC2013710 DOI: 10.1534/genetics.107.074120] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The cho-1 gene in Caenorhabditis elegans encodes a high-affinity plasma-membrane choline transporter believed to be rate limiting for acetylcholine (ACh) synthesis in cholinergic nerve terminals. We found that CHO-1 is expressed in most, but not all cholinergic neurons in C. elegans. cho-1 null mutants are viable and exhibit mild deficits in cholinergic behavior; they are slightly resistant to the acetylcholinesterase inhibitor aldicarb, and they exhibit reduced swimming rates in liquid. cho-1 mutants also fail to sustain swimming behavior; over a 33-min time course, cho-1 mutants slow down or stop swimming, whereas wild-type animals sustain the initial rate of swimming over the duration of the experiment. A functional CHO-1GFP fusion protein rescues these cho-1 mutant phenotypes and is enriched at cholinergic synapses. Although cho-1 mutants clearly exhibit defects in cholinergic behaviors, the loss of cho-1 function has surprisingly mild effects on cholinergic neurotransmission. However, reducing endogenous choline synthesis strongly enhances the phenotype of cho-1 mutants, giving rise to a synthetic uncoordinated phenotype. Our results indicate that both choline transport and de novo synthesis provide choline for ACh synthesis in C. elegans cholinergic neurons.
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Affiliation(s)
- Gregory P Mullen
- Program in Molecular, Cell and Developmental Biology, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma 73104, USA
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Norman KR, Cordes S, Qadota H, Rahmani P, Moerman DG. UNC-97/PINCH is involved in the assembly of integrin cell adhesion complexes in Caenorhabditis elegans body wall muscle. Dev Biol 2007; 309:45-55. [PMID: 17662976 DOI: 10.1016/j.ydbio.2007.06.014] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2007] [Revised: 06/15/2007] [Accepted: 06/18/2007] [Indexed: 01/29/2023]
Abstract
UNC-97/PINCH is an evolutionarily conserved protein that contains five LIM domains and is located at cell-extracellular matrix attachment sites known as cell adhesion complexes. To understand the role of UNC-97/PINCH in cell adhesion, we undertook a combined genetic and cell biological approach to identify the steps required to assemble cell adhesion complexes in Caenorhabditis elegans. First, we have generated a complete loss of function mutation in the unc-97 coding region. unc-97 null mutants arrest development during embryogenesis and reveal that the myofilament lattice and its attachment structures, which include PAT-4/ILK (integrin-linked kinase) and integrin fail to assemble into properly organized arrays. Although in the absence of UNC-97/PINCH, PAT-4/ILK and integrin fail to organize normally, they are capable of colocalizing together at the muscle cell membrane. Alternatively, in integrin and pat-4 mutants, UNC-97/PINCH fails to localize to the muscle cell membrane and instead is found diffusely throughout the muscle cell cytoplasm. In agreement with mammalian studies, we show that LIM domain 1 of UNC-97/PINCH is required for its interaction with PAT-4/ILK in yeast two-hybrid assays. Additionally, we find, by LIM domain deletion analysis, that LIM1 is required for the localization of UNC-97/PINCH to cell adhesion complexes. Our results provide evidence that UNC-97/PINCH is required for the development of C. elegans and is required for the formation of integrin based adhesion structures.
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Affiliation(s)
- Kenneth R Norman
- Department of Zoology, University of British Columbia, 6270 University Boulevard, Vancouver, BC, Canada V6T 1Z4
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Lecroisey C, Ségalat L, Gieseler K. The C. elegans dense body: anchoring and signaling structure of the muscle. J Muscle Res Cell Motil 2007; 28:79-87. [PMID: 17492481 DOI: 10.1007/s10974-007-9104-y] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2007] [Accepted: 03/26/2007] [Indexed: 10/23/2022]
Abstract
During evolution, both the architecture and the cellular physiology of muscles have been remarkably maintained. Striated muscles of invertebrates, although less complex, strongly resemble vertebrate skeletal muscles. In particular, the basic contractile unit called the sarcomere is almost identical between vertebrates and invertebrates. In vertebrate muscles, sarcomeric actin filaments are anchored to attachment points called Z-disks, which are linked to the extra-cellular matrix (ECM) by a muscle specific focal adhesion site called the costamere. In this review, we focus on the dense body of the animal model Caenorhabditis elegans. The C. elegans dense body is a structure that performs two in one roles at the same time, that of the Z-disk and of the costamere. The dense body is anchored in the muscle membrane and provides rigidity to the muscle by mechanically linking actin filaments to the ECM. In the last few years, it has become increasingly evident that, in addition to its structural role, the dense body also performs a signaling function in muscle cells. In this paper, we review recent advances in the understanding of the C. elegans dense body composition and function.
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Burt EC, Towers PR, Sattelle DB. Caenorhabditis elegans in the study of SMN-interacting proteins: a role for SMI-1, an orthologue of human Gemin2 and the identification of novel components of the SMN complex. INVERTEBRATE NEUROSCIENCE 2006; 6:145-59. [PMID: 16964508 DOI: 10.1007/s10158-006-0027-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2006] [Accepted: 07/07/2006] [Indexed: 01/23/2023]
Abstract
Spinal muscular atrophy is a common neuromuscular disorder caused by mutations in the survival motor neuron (SMN) gene. In mammals, SMN is tightly associated with Gemin2. To gain further insight into the functions of SMN and Gemin2, we have cloned and sequenced smi-1 (Survival of Motor neuron-Interacting protein 1), a C. elegans homologue of the human Gemin2 gene. We show that the SMI-1 expression pattern and RNA interference phenotype show considerable overlap with that previously reported for SMN-1. Finally, we demonstrate that the SMN-1 and SMI-1 proteins directly interact. Having demonstrated the utility of the C. elegans genetic model for investigating genes encoding SMN-interacting proteins, we have undertaken a yeast two-hybrid screen of a C. elegans cDNA library to identify novel proteins that interact with SMN-1. We show the direct interaction of SMN-1 with nine novel proteins, several of which may be involved in RNA metabolism.
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Affiliation(s)
- Emma C Burt
- Centre for Haematology, Bart's and The London, Queen Mary's School of Medicine, Institute of Cell and Molecular Science, 4 Newark Street, London, E1 2AT, UK
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Polet D, Lambrechts A, Ono K, Mah A, Peelman F, Vandekerckhove J, Baillie DL, Ampe C, Ono S. Caenorhabditis elegans expresses three functional profilins in a tissue-specific manner. ACTA ACUST UNITED AC 2006; 63:14-28. [PMID: 16317718 PMCID: PMC2575421 DOI: 10.1002/cm.20102] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Profilins are actin binding proteins, which also interact with polyphosphoinositides and proline-rich ligands. On the basis of the genome sequence, three diverse profilin homologues (PFN) are predicted to exist in Caenorhabditis elegans. We show that all three isoforms PFN-1, PFN-2, and PFN-3 are expressed in vivo and biochemical studies indicate they bind actin and influence actin dynamics in a similar manner. In addition, they bind poly(L-proline) and phosphatidylinositol 4,5-bisphosphate micelles. PFN-1 is essential whereas PFN-2 and PFN-3 are nonessential. Immunostainings revealed different expression patterns for the profilin isoforms. In embryos, PFN-1 localizes in the cytoplasm and to the cell-cell contacts at the early stages, and in the nerve ring during later stages. During late embryogenesis, expression of PFN-3 was specifically detected in body wall muscle cells. In adult worms, PFN-1 is expressed in the neurons, the vulva, and the somatic gonad, PFN-2 in the intestinal wall, the spermatheca, and the pharynx, and PFN-3 localizes in a striking dot-like fashion in body wall muscle. Thus the model organism Caenorhabditis elegans expresses three profilin isoforms and is the first invertebrate animal with tissue-specific profilin expression.
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Affiliation(s)
- D. Polet
- Department of Biochemistry, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium
- Department of Medical Protein Chemistry (VIB09), Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium
| | - A. Lambrechts
- Department of Biochemistry, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium
- Department of Medical Protein Chemistry (VIB09), Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium
| | - K. Ono
- Department of Pathology, Emory University, Atlanta, Georgia
| | - A. Mah
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia, Canada V5A 1S6
| | - F. Peelman
- Department of Biochemistry, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium
- Department of Medical Protein Chemistry (VIB09), Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium
| | - J. Vandekerckhove
- Department of Biochemistry, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium
- Department of Medical Protein Chemistry (VIB09), Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium
| | - D. L. Baillie
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia, Canada V5A 1S6
| | - C. Ampe
- Department of Biochemistry, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium
- Department of Medical Protein Chemistry (VIB09), Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium
- Correspondence to: C. Ampe, Department of Biochemistry, Faculty of Medicine and Health Sciences, Ghent University, A. Baertsoenkaai 3, B-9000 Ghent, Belgium. E-mail:
| | - S. Ono
- Department of Pathology, Emory University, Atlanta, Georgia
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McKeown CR, Han HF, Beckerle MC. Molecular characterization of the Caenorhabditis elegans ALP/Enigma gene alp-1. Dev Dyn 2006; 235:530-8. [PMID: 16278882 PMCID: PMC4301592 DOI: 10.1002/dvdy.20633] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Members of the ALP/Enigma family of PDZ-LIM proteins play a role in cytoskeletal anchorage and mutations in at least one member of this family are associated with human cardiomyopathy. Here, we describe the analysis of the Caenorhabditis elegans alp-1 gene. alp-1 is predicted to encode the entire nematode ALP/Enigma protein family, consisting of one ALP-related protein with a single LIM domain and three Enigma-like proteins containing four LIM domains. We demonstrate that the ALP-1 proteins are expressed in muscle cells, where they localize to actin anchorage and muscle attachment sites. We show that the PDZ domain of the ALP-1 proteins is sufficient to target the protein to the dense bodies, which are important actin anchorage sites in C. elegans body wall muscle. We demonstrate that the C. elegans ALP/Enigma proteins are also localized to cell-cell junctions and to both epithelial and muscle cell nuclei. These findings suggest new roles for the ALP/Enigma protein family that may lead to the understanding of their involvement in cardiomyopathy.
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Affiliation(s)
- Caroline R. McKeown
- Huntsman Cancer Institute, Department of Biology, University of Utah, Salt Lake City, Utah
| | - Hsiao-Fen Han
- Huntsman Cancer Institute, Department of Oncological Sciences, University of Utah, Salt Lake City, Utah
| | - Mary C. Beckerle
- Huntsman Cancer Institute, Department of Biology, University of Utah, Salt Lake City, Utah
- Huntsman Cancer Institute, Department of Oncological Sciences, University of Utah, Salt Lake City, Utah
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Hikita T, Qadota H, Tsuboi D, Taya S, Moerman DG, Kaibuchi K. Identification of a novel Cdc42 GEF that is localized to the PAT-3-mediated adhesive structure. Biochem Biophys Res Commun 2005; 335:139-45. [PMID: 16055082 DOI: 10.1016/j.bbrc.2005.07.068] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2005] [Accepted: 07/13/2005] [Indexed: 10/25/2022]
Abstract
In the model organism Caenorhabditis elegans, UNC-112 is colocalized with PAT-3/beta-integrin and is a critical protein in the formation of PAT-3-mediated adhesive structure in body-wall muscle cells. However, the signaling pathway downstream of PAT-3/UNC-112 is largely unknown. To clarify the signaling pathway from PAT-3/UNC-112 to the actin cytoskeleton, we searched for and identified a novel Dbl homology/pleckstrin homology (DH/PH) domain containing protein, UIG-1 (UNC-112-interacting guanine nucleotide exchange factor-1). UIG-1 was colocalized with UNC-112 at dense bodies in body-wall muscle cells. UIG-1 showed CDC-42-specific GEF activity in vitro and induced filopodia formation in NIH 3T3 cells. Depletion of CDC-42 or PAT-3 in the developmental stage, by RNAi, prevented the formation of continuous actin filament in body-wall muscle cells. Taken together, these results suggest that UIG-1 links a PAT-3/UNC-112 complex to the CDC-42 signaling pathway during muscle formation.
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Affiliation(s)
- Takao Hikita
- Department of Cell Pharmacology, Graduate School of Medicine, Nagoya University, 65 Tsurumai, Showa-ku, Nagoya, Aichi 466-8550, Japan
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