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Nicolas WJ, Shiriaeva A, Martynowycz MW, Grey AC, Ruma Y, Donaldson PJ, Gonen T. Structure of the lens MP20 mediated adhesive junction. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.13.594022. [PMID: 38798449 PMCID: PMC11118347 DOI: 10.1101/2024.05.13.594022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2024]
Abstract
Human lens fiber membrane intrinsic protein MP20 is the second most abundant membrane protein of the human eye lens. Despite decades of effort its structure and function remained elusive. Here, we determined the MicroED structure of full-length human MP20 in lipidic-cubic phase to a resolution of 3.5 Å. MP20 forms tetramers each of which contain 4 transmembrane α-helices that are packed against one another forming a helical bundle. Both the N- and C- termini of MP20 are cytoplasmic. We found that each MP20 tetramer formed adhesive interactions with an opposing tetramer in a head-to-head fashion. These interactions were mediated by the extracellular loops of the protein. The dimensions of the MP20 adhesive junctions are consistent with the 11 nm thin lens junctions. Investigation of MP20 localization in human lenses indicated that in young fiber cells MP20 was stored intracellularly in vesicles and upon fiber cell maturation MP20 inserted into the plasma membrane and restricted the extracellular space. Together these results suggest that MP20 forms lens thin junctions in vivo confirming its role as a structural protein in the human eye lens, essential for its optical transparency.
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Affiliation(s)
- William J. Nicolas
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, CA 90095
- Howard Hughes Medical Institute, University of California, Los Angeles, CA 90095
| | - Anna Shiriaeva
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, CA 90095
| | - Michael W. Martynowycz
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, CA 90095
| | - Angus C Grey
- Department of Physiology, School of Medical Sciences, University of Auckland, Auckland, NZ
| | - Yasmeen Ruma
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, CA 90095
- Howard Hughes Medical Institute, University of California, Los Angeles, CA 90095
| | - Paul J Donaldson
- Department of Physiology, School of Medical Sciences, University of Auckland, Auckland, NZ
| | - Tamir Gonen
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, CA 90095
- Howard Hughes Medical Institute, University of California, Los Angeles, CA 90095
- Department of Physiology, David Geffen School of Medicine, University of California, Los Angeles, CA 90095
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2
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Pashkova N, Peterson TA, Ptak CP, Winistorfer SC, Ahern CA, Shy ME, Piper RC. PMP22 associates with MPZ via their transmembrane domains and disrupting this interaction causes a loss-of-function phenotype similar to hereditary neuropathy associated with liability to pressure palsies (HNPP). BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.24.573255. [PMID: 38187781 PMCID: PMC10769442 DOI: 10.1101/2023.12.24.573255] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2024]
Abstract
PMP22 and MPZ are major myelin proteins in the peripheral nervous system. MPZ is a single pass integral membrane protein with an extracellular immunoglobulin (Ig)-like domain and works as an adhesion protein to hold myelin wraps together across the intraperiod line. Loss of MPZ causes severe demyelinating Charcot-Marie-Tooth (CMT) peripheral neuropathy. PMP22 is an integral membrane tetraspan protein belonging to the Claudin superfamily. Homozygous loss of PMP22 also leads to severe demyelinating neuropathy, and duplication of wildtype PMP22 causes the most common form of CMT, CMT1A. Yet the molecular functions provided by PMP22 and how its alteration causes CMT are unknown. Here we find that these abundant myelin proteins form a strong and specific complex. Mutagenesis and domain swapping experiments reveal that these proteins interact through interfaces within their transmembrane domains. We also find that the PMP22 A67T patient variant that causes an HNPP (Hereditary neuropathy with pressure palsies) phenotype, reflecting a heterozygous loss-of-function, maps to this interface. The PMP22 A67T variant results in the specific loss of MPZ association with PMP22 without affecting PMP22 localization to the plasma membrane or its interactions with other proteins. These data define the molecular basis for the MPZ∼PMP22 interaction and indicate that the MPZ∼PMP22 complex fulfills an important function in myelinating cells.
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3
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Quesnelle DC, Huang C, Boudreau JR, Lam A, Paw J, Bendena WG, Chin-Sang ID. C. elegans vab-6 encodes a KIF3A kinesin and functions cell non-autonomously to regulate epidermal morphogenesis. Dev Biol 2023; 497:33-41. [PMID: 36893881 DOI: 10.1016/j.ydbio.2023.02.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Revised: 02/01/2023] [Accepted: 02/27/2023] [Indexed: 03/09/2023]
Abstract
Cells undergo strict regulation to develop their shape in a process called morphogenesis. Caenorhabditis elegans with mutations in the variable abnormal (vab) class of genes have been shown to display epidermal and neuronal morphological defects. While several vab genes have been well-characterized, the function of the vab-6 gene remains unknown. Here, we show that vab-6 is synonymous with a subunit of the kinesin-II heterotrimeric motor complex called klp-20/Kif3a, a motor well-understood to be involved in developing sensory cilia in the nervous system. We show that certain klp-20 alleles cause animals to develop a bumpy body phenotype that is variable but most severe in mutants containing single amino-acid substitutions in the catalytic head-domain sites of the protein. Surprisingly, animals carrying a klp-20 null allele do not show the bumpy epidermal phenotype suggesting genetic redundancy and only when mutant versions of the KLP-20 protein are present, the epidermal phenotype is observed. The bumpy epidermal phenotype was not observed in other kinesin-2 mutants, suggesting that KLP-20 is functioning independently from its role in intraflagellar transport (IFT) during ciliogenesis. Interestingly, despite having such a prominent epidermal phenotype, KLP-20 is not expressed in the epidermis, strongly suggesting a cell non-autonomous role in which it regulates epidermal morphogenesis.
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Affiliation(s)
| | - Cindy Huang
- Department of Biology, Queen's University, Kingston, ON, Canada
| | | | - Annie Lam
- Department of Biology, Queen's University, Kingston, ON, Canada
| | - Jadine Paw
- Department of Biology, Queen's University, Kingston, ON, Canada
| | | | - Ian D Chin-Sang
- Department of Biology, Queen's University, Kingston, ON, Canada.
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4
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Wu LJ, Li F, Song Y, Zhang ZF, Fan YL, Liu TX. Proteome Analysis of Male Accessory Gland Secretions in the Diamondback Moth, Plutella xylostella (Lepidoptera: Plutellidae). INSECTS 2023; 14:132. [PMID: 36835702 PMCID: PMC9960318 DOI: 10.3390/insects14020132] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/04/2022] [Revised: 01/21/2023] [Accepted: 01/24/2023] [Indexed: 06/18/2023]
Abstract
In insects, male accessory gland proteins (ACPs) are important reproductive proteins secreted by male accessory glands (MAGs) of the internal male reproductive system. During mating, ACPs are transferred along with sperms inside female bodies and have a significant impact on the post-mating physiology changes of the females. Under sexual selection pressures, the ACPs exhibit remarkably rapid and divergent evolution and vary from species to species. The diamondback moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae), is a major insect pest of cruciferous vegetables worldwide. Mating has a profound impact on the females' behavior and physiology in this species. It is still unclear what the ACPs are in this species. In this study, two different proteomic methods were used to identify ACPs in P. xylostella. The proteins of MAGs were compared immediately before and after mating by using a tandem mass tags (TMT) quantitative proteomic analysis. The proteomes of copulatory bursas (CB) in mated females shortly after mating were also analyzed by the shotgun LC-MS/MS technique. In total, we identified 123 putative secreted ACPs. Comparing P. xylostella with other four insect ACPs, trypsins were the only ACPs detected in all insect species. We also identified some new insect ACPs, including proteins with chitin binding Peritrophin-A domain, PMP-22/ EMP/ MP20/ Claudin tight junction domain-containing protein, netrin-1, type II inositol 1,4,5-trisphosphate 5-phosphatase, two spaetzles, allatostatin-CC, and cuticular protein. This is the first time that ACPs have been identified and analyzed in P. xylostella. Our results have provided an important list of putative secreted ACPs, and have set the stage for further exploration of the functions of these putative proteins in P. xylostella reproduction.
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Affiliation(s)
- Li-Juan Wu
- State Key Laboratory for Crop Stress Biology in Arid Areas, College of Plant Protection, Northwest A&F University, Xianyang 712100, China
- Key Laboratory of Integrated Pest Management on Crops in Northwestern Loess Plateau, Ministry of Agriculture and Rural Affairs P. R. China, College of Plant Protection, Northwest A&F University, Xianyang 712100, China
| | - Fan Li
- State Key Laboratory for Crop Stress Biology in Arid Areas, College of Plant Protection, Northwest A&F University, Xianyang 712100, China
- Institute of Agricultural Sciences of Suqian, Jiangsu Academy of Agricultural Sciences, Suqian 223800, China
| | - Yue Song
- State Key Laboratory for Crop Stress Biology in Arid Areas, College of Plant Protection, Northwest A&F University, Xianyang 712100, China
- Key Laboratory of Integrated Pest Management on Crops in Northwestern Loess Plateau, Ministry of Agriculture and Rural Affairs P. R. China, College of Plant Protection, Northwest A&F University, Xianyang 712100, China
| | - Zhan-Feng Zhang
- State Key Laboratory for Crop Stress Biology in Arid Areas, College of Plant Protection, Northwest A&F University, Xianyang 712100, China
- Key Laboratory of Integrated Pest Management on Crops in Northwestern Loess Plateau, Ministry of Agriculture and Rural Affairs P. R. China, College of Plant Protection, Northwest A&F University, Xianyang 712100, China
| | - Yong-Liang Fan
- State Key Laboratory for Crop Stress Biology in Arid Areas, College of Plant Protection, Northwest A&F University, Xianyang 712100, China
- Key Laboratory of Integrated Pest Management on Crops in Northwestern Loess Plateau, Ministry of Agriculture and Rural Affairs P. R. China, College of Plant Protection, Northwest A&F University, Xianyang 712100, China
| | - Tong-Xian Liu
- State Key Laboratory for Crop Stress Biology in Arid Areas, College of Plant Protection, Northwest A&F University, Xianyang 712100, China
- Key Laboratory of Integrated Pest Management on Crops in Northwestern Loess Plateau, Ministry of Agriculture and Rural Affairs P. R. China, College of Plant Protection, Northwest A&F University, Xianyang 712100, China
- Institute of Entomology, Guizhou University, Guiyang 550025, China
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Hegsted A, Votra S, Christophe AM, Yingling CV, Sundaramurthy S, Pruyne D. Functional importance of an inverted formin C-terminal tail at morphologically dynamic epithelial junctions. Cytoskeleton (Hoboken) 2019; 76:322-336. [PMID: 31215743 DOI: 10.1002/cm.21547] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 05/30/2019] [Accepted: 06/09/2019] [Indexed: 11/10/2022]
Abstract
Epithelial cell-cell junctions have dual roles of accommodating morphological changes in an epithelium, while maintaining cohesion during those changes. An abundance of junction proteins has been identified, but many details on how intercellular junctions respond to morphological changes remain unclear. In Caenorhabditis elegans, the spermatheca is an epithelial sac that repeatedly dilates and constricts to allow ovulation. It is thought that the junctions between spermatheca epithelial cells undergo reversible partial unzipping to allow rapid dilation. Previously, we found that EXC-6, a C. elegans protein homolog of the human disease-associated formin INF2, is expressed in the spermatheca and promotes oocyte entry. We show here that EXC-6 localizes toward the apical aspect of the spermatheca epithelial junctions, and that the EXC-6-labeled junction domains "unzip" and dramatically flatten with oocyte entry into the spermatheca. We demonstrate that the C-terminal tail of EXC-6 is necessary and sufficient for junction localization. Moreover, expression of the tail alone worsens ovulation defects, suggesting this region not only mediates EXC-6 localization, but also interacts with other components important for junction remodeling.
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Affiliation(s)
- Anna Hegsted
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, Syracuse, New York
| | - SarahBeth Votra
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, Syracuse, New York
| | - Amylisa M Christophe
- Department of Clinical Laboratory Sciences, SUNY Upstate Medical University, Syracuse, New York
| | - Curtis V Yingling
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, Syracuse, New York
| | - Sumana Sundaramurthy
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, Syracuse, New York
| | - David Pruyne
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, Syracuse, New York
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6
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Regulation of Actin Dynamics in the C. elegans Somatic Gonad. J Dev Biol 2019; 7:jdb7010006. [PMID: 30897735 PMCID: PMC6473838 DOI: 10.3390/jdb7010006] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2019] [Revised: 03/13/2019] [Accepted: 03/15/2019] [Indexed: 11/25/2022] Open
Abstract
The reproductive system of the hermaphroditic nematode C. elegans consists of a series of contractile cell types—including the gonadal sheath cells, the spermathecal cells and the spermatheca–uterine valve—that contract in a coordinated manner to regulate oocyte entry and exit of the fertilized embryo into the uterus. Contraction is driven by acto-myosin contraction and relies on the development and maintenance of specialized acto-myosin networks in each cell type. Study of this system has revealed insights into the regulation of acto-myosin network assembly and contractility in vivo.
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7
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Tikiyani V, Li L, Sharma P, Liu H, Hu Z, Babu K. Wnt Secretion Is Regulated by the Tetraspan Protein HIC-1 through Its Interaction with Neurabin/NAB-1. Cell Rep 2018; 25:1856-1871.e6. [PMID: 30428353 PMCID: PMC6258899 DOI: 10.1016/j.celrep.2018.10.053] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Revised: 08/25/2018] [Accepted: 10/11/2018] [Indexed: 12/22/2022] Open
Abstract
The aberrant regulation of Wnt secretion is implicated in various neurological diseases. However, the mechanisms of Wnt release are still largely unknown. Here we describe the role of a C. elegans tetraspan protein, HIC-1, in maintaining normal Wnt release. We show that HIC-1 is expressed in cholinergic synapses and that mutants in hic-1 show increased levels of the acetylcholine receptor AChR/ACR-16. Our results suggest that HIC-1 maintains normal AChR/ACR-16 levels by regulating normal Wnt release from presynaptic neurons, as hic-1 mutants show an increase in secreted Wnt from cholinergic neurons. We further show that HIC-1 affects Wnt secretion by modulating the actin cytoskeleton through its interaction with the actin-binding protein NAB-1. In summary, we describe a protein, HIC-1, that functions as a neuromodulator by affecting postsynaptic AChR/ACR-16 levels by regulating presynaptic Wnt release from cholinergic motor neurons.
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Affiliation(s)
- Vina Tikiyani
- Indian Institute of Science Education and Research (IISER) Mohali, Knowledge City, Sector 81, SAS Nagar, Manauli PO 140306, Punjab, India
| | - Lei Li
- Queensland Brain Institute, Clem Jones Centre for Ageing Dementia Research (CJCADR), University of Queensland, Upland Road 79, St. Lucia, QLD 4072, Australia
| | - Pallavi Sharma
- Indian Institute of Science Education and Research (IISER) Mohali, Knowledge City, Sector 81, SAS Nagar, Manauli PO 140306, Punjab, India
| | - Haowen Liu
- Queensland Brain Institute, Clem Jones Centre for Ageing Dementia Research (CJCADR), University of Queensland, Upland Road 79, St. Lucia, QLD 4072, Australia
| | - Zhitao Hu
- Queensland Brain Institute, Clem Jones Centre for Ageing Dementia Research (CJCADR), University of Queensland, Upland Road 79, St. Lucia, QLD 4072, Australia
| | - Kavita Babu
- Indian Institute of Science Education and Research (IISER) Mohali, Knowledge City, Sector 81, SAS Nagar, Manauli PO 140306, Punjab, India.
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8
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Curto MÁ, Moro S, Yanguas F, Gutiérrez-González C, Valdivieso MH. The ancient claudin Dni2 facilitates yeast cell fusion by compartmentalizing Dni1 into a membrane subdomain. Cell Mol Life Sci 2018; 75:1687-1706. [PMID: 29134248 PMCID: PMC11105288 DOI: 10.1007/s00018-017-2709-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Revised: 10/10/2017] [Accepted: 11/03/2017] [Indexed: 12/20/2022]
Abstract
Dni1 and Dni2 facilitate cell fusion during mating. Here, we show that these proteins are interdependent for their localization in a plasma membrane subdomain, which we have termed the mating fusion domain. Dni1 compartmentation in the domain is required for cell fusion. The contribution of actin, sterol-dependent membrane organization, and Dni2 to this compartmentation was analysed, and the results showed that Dni2 plays the most relevant role in the process. In turn, the Dni2 exit from the endoplasmic reticulum depends on Dni1. These proteins share the presence of a cysteine motif in their first extracellular loop related to the claudin GLWxxC(8-10 aa)C signature motif. Structure-function analyses show that mutating each Dni1 conserved cysteine has mild effects, and that only simultaneous elimination of several cysteines leads to a mating defect. On the contrary, eliminating each single cysteine and the C-terminal tail in Dni2 abrogates Dni1 compartmentation and cell fusion. Sequence alignments show that claudin trans-membrane helixes bear small-XXX-small motifs at conserved positions. The fourth Dni2 trans-membrane helix tends to form homo-oligomers in Escherichia plasma membrane, and two concatenated small-XXX-small motifs are required for efficient oligomerization and for Dni2 export from the yeast endoplasmic reticulum. Together, our results strongly suggest that Dni2 is an ancient claudin that blocks Dni1 diffusion from the intercellular region where two plasma membranes are in close proximity, and that this function is required for Dni1 to facilitate cell fusion.
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Affiliation(s)
- M-Ángeles Curto
- Departamento de Microbiología y Genética, Universidad de Salamanca, Calle Zacarías González 2, Lab P1.1, Edificio IBFG, 37007, Salamanca, Spain
- Instituto de Biología Funcional y Genómica (IBFG), Consejo Superior de Investigaciones Científicas (CSIC), Calle Zacarías González 2, 37007, Salamanca, Spain
| | - Sandra Moro
- Departamento de Microbiología y Genética, Universidad de Salamanca, Calle Zacarías González 2, Lab P1.1, Edificio IBFG, 37007, Salamanca, Spain
- Instituto de Biología Funcional y Genómica (IBFG), Consejo Superior de Investigaciones Científicas (CSIC), Calle Zacarías González 2, 37007, Salamanca, Spain
| | - Francisco Yanguas
- Departamento de Microbiología y Genética, Universidad de Salamanca, Calle Zacarías González 2, Lab P1.1, Edificio IBFG, 37007, Salamanca, Spain
- Instituto de Biología Funcional y Genómica (IBFG), Consejo Superior de Investigaciones Científicas (CSIC), Calle Zacarías González 2, 37007, Salamanca, Spain
| | - Carmen Gutiérrez-González
- Instituto de Biología Funcional y Genómica (IBFG), Consejo Superior de Investigaciones Científicas (CSIC), Calle Zacarías González 2, 37007, Salamanca, Spain
| | - M-Henar Valdivieso
- Departamento de Microbiología y Genética, Universidad de Salamanca, Calle Zacarías González 2, Lab P1.1, Edificio IBFG, 37007, Salamanca, Spain.
- Instituto de Biología Funcional y Genómica (IBFG), Consejo Superior de Investigaciones Científicas (CSIC), Calle Zacarías González 2, 37007, Salamanca, Spain.
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9
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Sasidharan S, Borinskaya S, Patel F, Bernadskaya Y, Mandalapu S, Agapito M, Soto MC. WAVE regulates Cadherin junction assembly and turnover during epithelial polarization. Dev Biol 2017; 434:133-148. [PMID: 29223862 DOI: 10.1016/j.ydbio.2017.12.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Revised: 11/17/2017] [Accepted: 12/01/2017] [Indexed: 02/07/2023]
Abstract
Actin is an integral component of epithelial apical junctions, yet the interactions of branched actin regulators with apical junction components are still not clear. Biochemical data have shown that α-catenin inhibits Arp2/3-dependent branched actin. These results suggested that branched actin is only needed at earliest stages of apical junction development. We use live imaging in developing C. elegans embryos to test models for how WAVE-induced branched actin collaborates with other apical junction proteins during the essential process of junction formation and maturation. We uncover both early and late essential roles for WAVE in apical junction formation. Early, as the C. elegans intestinal epithelium becomes polarized, we find that WAVE components become enriched concurrently with the Cadherin components and before the DLG-1 apical accumulation. Live imaging of F-actin accumulation in polarizing intestine supports that the Cadherin complex components and branched actin regulators work together for apical actin enrichment. Later in junction development, the apical accumulation of WAVE and Cadherin components is shown to be interdependent: Cadherin complex loss alters WAVE accumulation, and WAVE complex loss increases Cadherin accumulation. To determine why Cadherin levels rise when WVE-1 is depleted, we use FRAP to analyze Cadherin dynamics and find that loss of WAVE as well as of the trafficking protein EHD-1/RME-1 increases Cadherin dynamics. EM studies in adults depleted of branched actin regulators support that WVE-1 maintains established junctions, presumably through its trafficking effect on Cadherin. Thus we propose a developmental model for junction formation where branched actin regulators are tightly interconnected with Cadherin junctions through their previously unappreciated role in Cadherin transport.
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Affiliation(s)
- Shashikala Sasidharan
- Department of Pathology and Laboratory Medicine, Rutgers - Robert Wood Johnson Medical School, 675 Hoes Lane, Piscataway, NJ 08854, USA
| | - Sofya Borinskaya
- Department of Pathology and Laboratory Medicine, Rutgers - Robert Wood Johnson Medical School, 675 Hoes Lane, Piscataway, NJ 08854, USA
| | - Falshruti Patel
- Department of Pathology and Laboratory Medicine, Rutgers - Robert Wood Johnson Medical School, 675 Hoes Lane, Piscataway, NJ 08854, USA
| | - Yelena Bernadskaya
- Department of Pathology and Laboratory Medicine, Rutgers - Robert Wood Johnson Medical School, 675 Hoes Lane, Piscataway, NJ 08854, USA
| | - Sailaja Mandalapu
- Department of Pathology and Laboratory Medicine, Rutgers - Robert Wood Johnson Medical School, 675 Hoes Lane, Piscataway, NJ 08854, USA
| | - Maria Agapito
- Department of Pathology and Laboratory Medicine, Rutgers - Robert Wood Johnson Medical School, 675 Hoes Lane, Piscataway, NJ 08854, USA
| | - Martha C Soto
- Department of Pathology and Laboratory Medicine, Rutgers - Robert Wood Johnson Medical School, 675 Hoes Lane, Piscataway, NJ 08854, USA.
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10
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Abstract
The claudin family of tetraspan transmembrane proteins is essential for tight junction formation and regulation of paracellular transport between epithelial cells. Claudins also play a role in apical-basal cell polarity, cell adhesion and link the tight junction to the actin cytoskeleton to exert effects on cell shape. The function of claudins in paracellular transport has been extensively studied through loss-of-function and gain-of-function studies in cell lines and in animal models, however, their role in morphogenesis has been less appreciated. In this review, we will highlight the importance of claudins during morphogenesis by specifically focusing on their critical functions in generating epithelial tubes, lumens, and tubular networks during organ formation.
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Affiliation(s)
- Amanda I Baumholtz
- a Department of Human Genetics , McGill University , Montréal , Québec , Canada.,b The Research Institute of the McGill University Health Centre , Montréal , Québec , Canada
| | - Indra R Gupta
- a Department of Human Genetics , McGill University , Montréal , Québec , Canada.,b The Research Institute of the McGill University Health Centre , Montréal , Québec , Canada.,c Department of Pediatrics , McGill University , Montréal , Québec , Canada
| | - Aimee K Ryan
- a Department of Human Genetics , McGill University , Montréal , Québec , Canada.,b The Research Institute of the McGill University Health Centre , Montréal , Québec , Canada.,c Department of Pediatrics , McGill University , Montréal , Québec , Canada
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11
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Suzuki H, Tani K, Fujiyoshi Y. Crystal structures of claudins: insights into their intermolecular interactions. Ann N Y Acad Sci 2017; 1397:25-34. [PMID: 28605828 DOI: 10.1111/nyas.13371] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Revised: 04/06/2017] [Accepted: 04/10/2017] [Indexed: 12/14/2022]
Abstract
Claudins are four-transmembrane proteins that constitute the backbone of tight junction strands via self-polymerization in the apicolateral membranes of epithelial cells. Together with their cell-cell adhesion function, claudin proteins form the paracellular barrier and/or channels through epithelial cell sheets whose permeability is primarily dependent on the claudin subtype. Recently determined crystal structures of several claudins revealed the unique claudin fold of four transmembrane helices in a left-handed helical bundle with an extracellular β-sheet domain. Here, we focus on the structural basis of the intermolecular interactions between claudin molecules and between the Clostridium perfringens enterotoxin and its receptor claudins.
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Affiliation(s)
- Hiroshi Suzuki
- Cellular and Structural Physiology Institute (CeSPI), Nagoya University, Chikusa, Nagoya, Japan
| | - Kazutoshi Tani
- Cellular and Structural Physiology Institute (CeSPI), Nagoya University, Chikusa, Nagoya, Japan
| | - Yoshinori Fujiyoshi
- Cellular and Structural Physiology Institute (CeSPI), Nagoya University, Chikusa, Nagoya, Japan.,Department of Basic Medical Science, Graduate School of Pharmaceutical Science, Nagoya University, Chikusa, Nagoya, Japan
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12
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Sidik SM, Huet D, Ganesan SM, Huynh MH, Wang T, Nasamu AS, Thiru P, Saeij JPJ, Carruthers VB, Niles JC, Lourido S. A Genome-wide CRISPR Screen in Toxoplasma Identifies Essential Apicomplexan Genes. Cell 2016; 166:1423-1435.e12. [PMID: 27594426 PMCID: PMC5017925 DOI: 10.1016/j.cell.2016.08.019] [Citation(s) in RCA: 511] [Impact Index Per Article: 63.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Revised: 07/25/2016] [Accepted: 08/05/2016] [Indexed: 12/11/2022]
Abstract
Apicomplexan parasites are leading causes of human and livestock diseases such as malaria and toxoplasmosis, yet most of their genes remain uncharacterized. Here, we present the first genome-wide genetic screen of an apicomplexan. We adapted CRISPR/Cas9 to assess the contribution of each gene from the parasite Toxoplasma gondii during infection of human fibroblasts. Our analysis defines ∼200 previously uncharacterized, fitness-conferring genes unique to the phylum, from which 16 were investigated, revealing essential functions during infection of human cells. Secondary screens identify as an invasion factor the claudin-like apicomplexan microneme protein (CLAMP), which resembles mammalian tight-junction proteins and localizes to secretory organelles, making it critical to the initiation of infection. CLAMP is present throughout sequenced apicomplexan genomes and is essential during the asexual stages of the malaria parasite Plasmodium falciparum. These results provide broad-based functional information on T. gondii genes and will facilitate future approaches to expand the horizon of antiparasitic interventions.
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Affiliation(s)
- Saima M Sidik
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA
| | - Diego Huet
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA
| | - Suresh M Ganesan
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - My-Hang Huynh
- Department of Microbiology and Immunology, University of Michigan School of Medicine, Ann Arbor, MI 48109, USA
| | - Tim Wang
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA; Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139 USA; Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Armiyaw S Nasamu
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Prathapan Thiru
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA
| | - Jeroen P J Saeij
- Department of Pathology, Microbiology and Immunology, University of California, Davis, Davis, CA 95616, USA
| | - Vern B Carruthers
- Department of Microbiology and Immunology, University of Michigan School of Medicine, Ann Arbor, MI 48109, USA
| | - Jacquin C Niles
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Sebastian Lourido
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA.
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13
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Structure of the voltage-gated calcium channel Ca(v)1.1 at 3.6 Å resolution. Nature 2016; 537:191-196. [PMID: 27580036 DOI: 10.1038/nature19321] [Citation(s) in RCA: 314] [Impact Index Per Article: 39.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2016] [Accepted: 07/15/2016] [Indexed: 12/12/2022]
Abstract
The voltage-gated calcium (Cav) channels convert membrane electrical signals to intracellular Ca2+-mediated events. Among the ten subtypes of Cav channel in mammals, Cav1.1 is specified for the excitation-contraction coupling of skeletal muscles. Here we present the cryo-electron microscopy structure of the rabbit Cav1.1 complex at a nominal resolution of 3.6 Å. The inner gate of the ion-conducting α1-subunit is closed and all four voltage-sensing domains adopt an 'up' conformation, suggesting a potentially inactivated state. The extended extracellular loops of the pore domain, which are stabilized by multiple disulfide bonds, form a windowed dome above the selectivity filter. One side of the dome provides the docking site for the α2δ-1-subunit, while the other side may attract cations through its negative surface potential. The intracellular I-II and III-IV linker helices interact with the β1a-subunit and the carboxy-terminal domain of α1, respectively. Classification of the particles yielded two additional reconstructions that reveal pronounced displacement of β1a and adjacent elements in α1. The atomic model of the Cav1.1 complex establishes a foundation for mechanistic understanding of excitation-contraction coupling and provides a three-dimensional template for molecular interpretations of the functions and disease mechanisms of Cav and Nav channels.
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14
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Dong Y, Simske JS. Vertebrate Claudin/PMP22/EMP22/MP20 family protein TMEM47 regulates epithelial cell junction maturation and morphogenesis. Dev Dyn 2016; 245:653-66. [PMID: 26990309 DOI: 10.1002/dvdy.24404] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2015] [Revised: 02/18/2016] [Accepted: 02/24/2016] [Indexed: 01/22/2023] Open
Abstract
BACKGROUND TMEM47 is the vertebrate orthologue of C. elegans VAB-9, a tetraspan adherens junction protein in the PMP22/EMP/Claudin family of proteins. VAB-9 regulates cell morphology and adhesion in C. elegans and TMEM47 is expressed during kidney development and regulates the activity of Fyn. The conserved functions of VAB-9 and TMEM47 are not well understood. RESULTS expression of TMEM47 in C. elegans functionally rescues vab-9 mutations. Unlike Claudins, expression of TMEM47 in L fibroblasts does not generate tight junction strands; instead, membrane localization requires E-cadherin expression. Temporally, TMEM47 localizes at cell junctions first with E-cadherin before ZO-1 colocalization and in polarized epithelia, TMEM47 colocalizes with adherens junction proteins. By immunoprecipitation, TMEM47 associates with classical adherens junction proteins, but also with tight junction proteins Par6B and aPKCλ. Over-expression of TMEM47 in MDCK cells decreases apical surface area, increases activated myosin light chain at cell-cell contacts, disrupts cell polarity and morphology, delays cell junction reassembly following calcium switch, and selectively interferes with tight junction assembly. Reduced TMEM47 expression results in opposite phenotypes. CONCLUSIONS TMEM47 regulates the localization of a subset of tight junction proteins, associated actomyosin structures, cell morphology, and participates in developmental transitions from adherens to tight junctions. Developmental Dynamics 245:653-666, 2016. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Yi Dong
- Rammelkamp Center for Education and Research, MetroHealth Medical Center, Cleveland, Ohio
| | - Jeffrey S Simske
- Rammelkamp Center for Education and Research, MetroHealth Medical Center, Cleveland, Ohio
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15
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Wu J, Yan Z, Li Z, Yan C, Lu S, Dong M, Yan N. Structure of the voltage-gated calcium channel Cav1.1 complex. Science 2016; 350:aad2395. [PMID: 26680202 DOI: 10.1126/science.aad2395] [Citation(s) in RCA: 230] [Impact Index Per Article: 28.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The voltage-gated calcium channel Ca(v)1.1 is engaged in the excitation-contraction coupling of skeletal muscles. The Ca(v)1.1 complex consists of the pore-forming subunit α1 and auxiliary subunits α2δ, β, and γ. We report the structure of the rabbit Ca(v)1.1 complex determined by single-particle cryo-electron microscopy. The four homologous repeats of the α1 subunit are arranged clockwise in the extracellular view. The γ subunit, whose structure resembles claudins, interacts with the voltage-sensing domain of repeat IV (VSD(IV)), whereas the cytosolic β subunit is located adjacent to VSD(II) of α1. The α2 subunit interacts with the extracellular loops of repeats I to III through its VWA and Cache1 domains. The structure reveals the architecture of a prototypical eukaryotic Ca(v) channel and provides a framework for understanding the function and disease mechanisms of Ca(v) and Na(v) channels.
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Affiliation(s)
- Jianping Wu
- State Key Laboratory of Membrane Biology, Tsinghua University, Beijing 100084, China. Tsinghua-Peking Joint Center for Life Sciences, Tsinghua University, Beijing 100084, China. Center for Structural Biology, School of Life Sciences and School of Medicine, Tsinghua University, Beijing 100084, China
| | - Zhen Yan
- State Key Laboratory of Membrane Biology, Tsinghua University, Beijing 100084, China. Tsinghua-Peking Joint Center for Life Sciences, Tsinghua University, Beijing 100084, China. Center for Structural Biology, School of Life Sciences and School of Medicine, Tsinghua University, Beijing 100084, China
| | - Zhangqiang Li
- State Key Laboratory of Membrane Biology, Tsinghua University, Beijing 100084, China. Tsinghua-Peking Joint Center for Life Sciences, Tsinghua University, Beijing 100084, China. Center for Structural Biology, School of Life Sciences and School of Medicine, Tsinghua University, Beijing 100084, China
| | - Chuangye Yan
- State Key Laboratory of Membrane Biology, Tsinghua University, Beijing 100084, China. Tsinghua-Peking Joint Center for Life Sciences, Tsinghua University, Beijing 100084, China. Center for Structural Biology, School of Life Sciences and School of Medicine, Tsinghua University, Beijing 100084, China
| | - Shan Lu
- National Institute of Biological Sciences, Beijing 102206, China
| | - Mengqiu Dong
- National Institute of Biological Sciences, Beijing 102206, China
| | - Nieng Yan
- State Key Laboratory of Membrane Biology, Tsinghua University, Beijing 100084, China. Tsinghua-Peking Joint Center for Life Sciences, Tsinghua University, Beijing 100084, China. Center for Structural Biology, School of Life Sciences and School of Medicine, Tsinghua University, Beijing 100084, China.
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16
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Deligiannaki M, Casper AL, Jung C, Gaul U. Pasiflora proteins are novel core components of the septate junction. Development 2015; 142:3046-57. [PMID: 26329602 PMCID: PMC4582180 DOI: 10.1242/dev.119412] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Epithelial sheets play essential roles as selective barriers insulating the body from the environment and establishing distinct chemical compartments within it. In invertebrate epithelia, septate junctions (SJs) consist of large multi-protein complexes that localize at the apicolateral membrane and mediate barrier function. Here, we report the identification of two novel SJ components, Pasiflora1 and Pasiflora2, through a genome-wide glial RNAi screen in Drosophila. Pasiflora mutants show permeable blood-brain and tracheal barriers, overelongated tracheal tubes and mislocalization of SJ proteins. Consistent with the observed phenotypes, the genes are co-expressed in embryonic epithelia and glia and are required cell-autonomously to exert their function. Pasiflora1 and Pasiflora2 belong to a previously uncharacterized family of tetraspan membrane proteins conserved across the protostome-deuterostome divide. Both proteins localize at SJs and their apicolateral membrane accumulation depends on other complex components. In fluorescence recovery after photobleaching experiments we demonstrate that pasiflora proteins are core SJ components as they are required for complex formation and exhibit restricted mobility within the membrane of wild-type epithelial cells, but rapid diffusion in cells with disrupted SJs. Taken together, our results show that Pasiflora1 and Pasiflora2 are novel integral components of the SJ and implicate a new family of tetraspan proteins in the function of these ancient and crucial cell junctions.
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Affiliation(s)
- Myrto Deligiannaki
- Gene Center, Department of Biochemistry, Center of Protein Science CIPSM, Ludwigs-Maximilians University, Feodor-Lynen-Str. 25, Munich 81377, Germany
| | - Abbie L Casper
- Gene Center, Department of Biochemistry, Center of Protein Science CIPSM, Ludwigs-Maximilians University, Feodor-Lynen-Str. 25, Munich 81377, Germany
| | - Christophe Jung
- Gene Center, Department of Biochemistry, Center of Protein Science CIPSM, Ludwigs-Maximilians University, Feodor-Lynen-Str. 25, Munich 81377, Germany
| | - Ulrike Gaul
- Gene Center, Department of Biochemistry, Center of Protein Science CIPSM, Ludwigs-Maximilians University, Feodor-Lynen-Str. 25, Munich 81377, Germany
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17
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Abstract
The establishment and maintenance of epithelial cell-cell junctions is crucially important to regulate adhesion, apico-basal polarity and motility of epithelial cells, and ultimately controls the architecture and physiology of epithelial organs. Junctions are supported, shaped and regulated by cytoskeletal filaments, whose dynamic organization and contractility are finely tuned by GTPases of the Rho family, primarily RhoA, Rac1 and Cdc42. Recent research has identified new molecular mechanisms underlying the cross-talk between these GTPases and epithelial junctions. Here we briefly summarize the current knowledge about the organization, molecular evolution and cytoskeletal anchoring of cell-cell junctions, and we comment on the most recent advances in the characterization of the interactions between Rho GTPases and junctional proteins, and their consequences with regards to junction assembly and regulation of cell behavior in vertebrate model systems. The concept of “zonular signalosome” is proposed, which highlights the close functional relationship between proteins of zonular junctions (zonulae occludentes and adhaerentes) and the control of cytoskeletal organization and signaling through Rho GTPases, transcription factors, and their effectors.
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Key Words
- AJ, adherens junction
- AMOT, angiomotin
- AMPK, Adenosine Monophosphate-Activated Protein Kinase
- APC, adenomatous poliposis coli
- CD2AP, CD2-associated protein
- CGN, cingulin
- CGNL1, paracingulin
- Cdc42
- Cdc42, cell division cycle 42
- DLC, deleted in liver cancer
- Dbl, diffuse B-cell lymphoma
- EPLIN, epithelial protein lost in neoplasm
- ERK, extracellular regulated kinase
- FERM, four.point.one, ezrin, radixin, moesin
- FGD5, FYVE, RhoGEF and PH domain containing 5
- GAP, GTPase activating protein
- GEF, guanine nucleotide exchange factor
- GST, glutathione -S- transferase; JAM = junctional adhesion molecule
- MCF-7, Michigan Cancer Foundation - 7
- MDCK, Madin Darby Canine Kidney
- MKLP1, mitotic kinesin-like protein-1
- MRCK, myotonic dystrophy-related Cdc42-binding kinase
- MgcRacGAP, male germ cell racGAP
- PA, puncta adhaerentia
- PAK, p21-activated kinase; PATJ, Pals1 associated tight junction protein
- PCNA, proliferating cell nuclear antigen
- PDZ, Post synaptic density protein (PSD95), Drosophila, disc large tumour suppressor (DlgA), and zonula occludens-1
- PLEKHA7, pleckstrin homology domain containing, family A member 7
- RICH-1, RhoGAP interacting with CIP4 homologues
- ROCK, Rho-associated protein kinase
- Rac
- Rho
- SH3BP1, (SH3 domain 490 binding protein-1)
- TJ, tight junction
- Tbx-3, T-box-3
- Tiam, Tumor invasion and metastasis
- WASP, Wiskott-Aldrich Syndrome Protein
- WAVE, WASP family Verprolin-homologous protein
- ZA, zonula adhaerens
- ZO, zonula occludens
- ZONAB, (ZO-1)–associated nucleic acid binding protein.
- cytoseleton
- epithelium
- junctions
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Affiliation(s)
- Sandra Citi
- a Department of Cell Biology ; University of Geneva ; Geneva , Switzerland
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Capaldo CT, Nusrat A. Claudin switching: Physiological plasticity of the Tight Junction. Semin Cell Dev Biol 2015; 42:22-9. [PMID: 25957515 DOI: 10.1016/j.semcdb.2015.04.003] [Citation(s) in RCA: 69] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Revised: 04/15/2015] [Accepted: 04/16/2015] [Indexed: 01/22/2023]
Abstract
Tight Junctions (TJs) are multi-molecular complexes in epithelial tissues that regulate paracellular permeability. Within the TJ complex, claudins proteins span the paracellular space to form a seal between adjacent cells. This seal allows regulated passage of ions, fluids, and solutes, contingent upon the complement of claudins expressed. With as many as 27 claudins in the human genome, the TJ seal is complex indeed. This review focuses on changes in claudin expression within the epithelial cells of the gastrointestinal tract, where claudin differentiation results in several physiologically distinct TJs within the lifetime of the cell. We also review mechanistic studies revealing that TJs are highly dynamic, with the potential to undergo molecular remodeling while structurally intact. Therefore, physiologic Tight Junction plasticity involves both the adaptability of claudin expression and gene specific retention in the TJ; a process we term claudin switching.
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Affiliation(s)
- Christopher T Capaldo
- Epithelial Pathobiology and Mucosal Inflammation Research Unit, Department of Pathology and Laboratory Medicine, Emory University, Atlanta, GA 30322, United States
| | - Asma Nusrat
- Epithelial Pathobiology and Mucosal Inflammation Research Unit, Department of Pathology and Laboratory Medicine, Emory University, Atlanta, GA 30322, United States; Department of Pathology, University of Michigan, Ann Arbor, MI 48109, United States.
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Moran Y, Zakon HH. The evolution of the four subunits of voltage-gated calcium channels: ancient roots, increasing complexity, and multiple losses. Genome Biol Evol 2014; 6:2210-7. [PMID: 25146647 PMCID: PMC4202318 DOI: 10.1093/gbe/evu177] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
The alpha subunits of voltage-gated calcium channels (Cavs) are large transmembrane proteins responsible for crucial physiological processes in excitable cells. They are assisted by three auxiliary subunits that can modulate their electrical behavior. Little is known about the evolution and roles of the various subunits of Cavs in nonbilaterian animals and in nonanimal lineages. For this reason, we mapped the phyletic distribution of the four channel subunits and reconstructed their phylogeny. Although alpha subunits have deep evolutionary roots as ancient as the split between plants and opistokonths, beta subunits appeared in the last common ancestor of animals and their close-relatives choanoflagellates, gamma subunits are a bilaterian novelty and alpha2/delta subunits appeared in the lineage of Placozoa, Cnidaria, and Bilateria. We note that gene losses were extremely common in the evolution of Cavs, with noticeable losses in multiple clades of subfamilies and also of whole Cav families. As in vertebrates, but not protostomes, Cav channel genes duplicated in Cnidaria. We characterized by in situ hybridization the tissue distribution of alpha subunits in the sea anemone Nematostella vectensis, a nonbilaterian animal possessing all three Cav subfamilies common to Bilateria. We find that some of the alpha subunit subtypes exhibit distinct spatiotemporal expression patterns. Further, all six sea anemone alpha subunit subtypes are conserved in stony corals, which separated from anemones 500 MA. This unexpected conservation together with the expression patterns strongly supports the notion that these subtypes carry unique functional roles.
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Affiliation(s)
- Yehu Moran
- Department of Ecology, Evolution and Behavior, Alexander Silberman Institute of Life Sciences, Faculty of Science, Hebrew University of Jerusalem, Israel
| | - Harold H Zakon
- Department of Integrative Biology and Center for Computational Biology and Bioinformatics, University of Texas, Austin Department of Neuroscience, University of Texas at Austin Josephine Bay Paul Center for Molecular Biology and Evolution, Marine Biological Laboratory, Woods Hole, Massachusetts
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20
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Abstract
Since the discovery of Claudins more than a decade ago, much has been learned about their structure-function relationships. Claudins are tetraspan membrane proteins responsible for the formation of tight junctions. In this capacity, Claudins form a tissue-specific selective permeability barrier that is critical for the function of the tissue. Claudins are developmentally regulated and expressed in a tissue- and cell-specific manner; chronic changes in their expression are associated with various disease states. The studies that have been put together in this Special Issue provide updates on both current knowledge as well as some of the unanswered questions and challenges in the field.
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Affiliation(s)
- Kursad Turksen
- Regenerative Medicine Program; Sprott Centre for Stem Cell Research; Ottawa Hospital Research Institute; Ottawa, ON Canada
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