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Naturale VF, Pickett MA, Feldman JL. Context matters: Lessons in epithelial polarity from the Caenorhabditis elegans intestine and other tissues. Curr Top Dev Biol 2023; 154:37-71. [PMID: 37100523 DOI: 10.1016/bs.ctdb.2023.02.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/28/2023]
Abstract
Epithelia are tissues with diverse morphologies and functions across metazoans, ranging from vast cell sheets encasing internal organs to internal tubes facilitating nutrient uptake, all of which require establishment of apical-basolateral polarity axes. While all epithelia tend to polarize the same components, how these components are deployed to drive polarization is largely context-dependent and likely shaped by tissue-specific differences in development and ultimate functions of polarizing primordia. The nematode Caenorhabditis elegans (C. elegans) offers exceptional imaging and genetic tools and possesses unique epithelia with well-described origins and roles, making it an excellent model to investigate polarity mechanisms. In this review, we highlight the interplay between epithelial polarization, development, and function by describing symmetry breaking and polarity establishment in a particularly well-characterized epithelium, the C. elegans intestine. We compare intestinal polarization to polarity programs in two other C. elegans epithelia, the pharynx and epidermis, correlating divergent mechanisms with tissue-specific differences in geometry, embryonic environment, and function. Together, we emphasize the importance of investigating polarization mechanisms against the backdrop of tissue-specific contexts, while also underscoring the benefits of cross-tissue comparisons of polarity.
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Affiliation(s)
- Victor F Naturale
- Department of Biology, Stanford University, Stanford, CA, United States
| | - Melissa A Pickett
- Department of Biology, Stanford University, Stanford, CA, United States; Department of Biological Sciences, San José State University, San José, CA, United States
| | - Jessica L Feldman
- Department of Biology, Stanford University, Stanford, CA, United States.
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Roberts S, Delury C, Marsh E. The PDZ protein discs-large (DLG): the 'Jekyll and Hyde' of the epithelial polarity proteins. FEBS J 2012; 279:3549-3558. [PMID: 22846345 DOI: 10.1111/j.1742-4658.2012.08729.x] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2012] [Revised: 07/16/2012] [Accepted: 07/26/2012] [Indexed: 12/25/2022]
Abstract
Discs-large (DLG) is a multi-PDZ domain-containing protein that belongs to the family of molecular scaffolding proteins known as membrane guanylate kinases or MAGUKs. DLG is a component of the Scribble polarity complex and genetic analyses of DLG in Drosophila have identified a role for the protein in several key biological processes including the regulation of apico-basal polarity of epithelial cells, as well as other polarity processes such as asymmetric cell division and cell invasion. Disturbance of DLG function leads to uncontrolled epithelial cell proliferation and neoplastic transformation, thereby defining DLG as a potential tumour suppressor. However, whether mammalian homologues of DLG (DLG1, DLG2, DLG3 and DLG4) also possess tumour suppressor functions is not known. In this minireview, we focus on the biological functions of DLG1 in human epithelial cells and on how the function of this MAGUK relates to its intracellular location. We examine some of the evidence that implies that DLG has both tumour suppressor and, paradoxically, oncogenic functions depending upon the precise cellular context.
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Affiliation(s)
- Sally Roberts
- School of Cancer Sciences, University of Birmingham, UK
| | - Craig Delury
- School of Cancer Sciences, University of Birmingham, UK
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SAX-7/L1CAM and HMR-1/cadherin function redundantly in blastomere compaction and non-muscle myosin accumulation during Caenorhabditis elegans gastrulation. Dev Biol 2010; 344:731-44. [PMID: 20515680 DOI: 10.1016/j.ydbio.2010.05.507] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2010] [Accepted: 05/24/2010] [Indexed: 01/13/2023]
Abstract
Gastrulation is the first major morphogenetic movement in development and requires dynamic regulation of cell adhesion and the cytoskeleton. Caenorhabditis elegans gastrulation begins with the migration of the two endodermal precursors, Ea and Ep, from the surface of the embryo into the interior. Ea/Ep migration provides a relatively simple system to examine the intersection of cell adhesion, cell signaling, and cell movement. Ea/Ep ingression depends on correct cell fate specification and polarization, apical myosin accumulation, and Wnt activated actomyosin contraction that drives apical constriction and ingression (Lee et al., 2006; Nance et al., 2005). Here, we show that Ea/Ep ingression also requires the function of either HMR-1/cadherin or SAX-7/L1CAM. Both cadherin complex components and L1CAM are localized at all sites of cell-cell contact during gastrulation. Either system is sufficient for Ea/Ep ingression, but loss of both together leads to a failure of apical constriction and ingression. Similar results are seen with isolated blastomeres. Ea/Ep are properly specified and appear to display correct apical-basal polarity in sax-7(eq1);hmr-1(RNAi) embryos. Significantly, in sax-7(eq1);hmr-1(RNAi) embryos, Ea and Ep fail to accumulate myosin (NMY-2Colon, two colonsGFP) at their apical surfaces, but in either sax-7(eq1) or hmr-1(RNAi) embryos, apical myosin accumulation is comparable to wild type. Thus, the cadherin and L1CAM adhesion systems are redundantly required for localized myosin accumulation and hence for actomyosin contractility during gastrulation. We also show that sax-7 and hmr-1 function are redundantly required for Wnt-dependent spindle polarization during division of the ABar blastomere, indicating that these cell surface proteins redundantly regulate multiple developmental events in early embryos.
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Carberry K, Wiesenfahrt T, Windoffer R, Bossinger O, Leube RE. Intermediate filaments in Caenorhabditis elegans. ACTA ACUST UNITED AC 2009; 66:852-64. [PMID: 19437512 DOI: 10.1002/cm.20372] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Intermediate filaments (IFs) make up one of the three major fibrous cytoskeletal systems in metazoans. Numerous IF polypeptides are synthesized in cell type-specific combinations suggesting specialized functions. The review concentrates on IFs in the model organism Caenorhabditis elegans which carries great promise to elucidate the still unresolved mechanisms of IF assembly into complex networks and to determine IF function in a living organism. In contrast to Drosophila melanogaster, which lacks cytoplasmic IFs altogether, the nematode genome contains 11 genes coding for cytoplasmic IFs and only a single gene for a nuclear lamin. Its cytoplasmic IFs are expressed in developmentally and spatially defined patterns. As an example we present the case of the intestinal IFs which are abundant in the mechanically resilient endotube, a prominent feature of the C. elegans intestinal terminal web region. This IF-rich structure brings together all three cytoskeletal filaments that are integrated into a coherent entity by the C. elegans apical junction (CeAJ) thereby completely surrounding and stabilizing the intestinal lumen with its characteristic brush border. Concepts on the developmental establishment of the endotube in relation to polarization and its function for maintenance of epithelial integrity are discussed. Furthermore, possible connections of the cytoplasmic cytoskeleton to the nuclear lamin IFs and the importance of these links for nuclear positioning are summarized.
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Affiliation(s)
- Katrin Carberry
- Institute of Molecular and Cellular Anatomy, RWTH Aachen University, 52074 Aachen, Germany
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Lynch AM, Hardin J. The assembly and maintenance of epithelial junctions in C. elegans. Front Biosci (Landmark Ed) 2009; 14:1414-32. [PMID: 19273138 DOI: 10.2741/3316] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The epithelial tissues of the C. elegans embryo provide a "minimalist" system for examining phylogenetically conserved proteins that function in epithelial polarity and cell-cell adhesion in a multicellular organism. In this review, we provide an overview of three major molecular complexes at the apical surface of epithelial cells in the C. elegans embryo: the cadherin-catenin complex, the more basal DLG-1/AJM-1 complex, and the apical membrane domain, which shares similarities with the subapical complex in Drosophila and the PAR/aPKC complex in vertebrates. We discuss how the assembly of these complexes contributes to epithelial polarity and adhesion, proteins that act as effectors and/or regulators of each subdomain, and how these complexes functionally interact during embryonic morphogenesis. Although much remains to be clarified, significant progress has been made in recent years to clarify the role of these protein complexes in epithelial morphogenesis, and suggests that C. elegans will continue to be a fruitful system in which to elucidate functional roles for these proteins in a living embryo.
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Affiliation(s)
- Allison M Lynch
- Program in Genetics, University of Wisconsin-Madison, University of Wisconsin-Madison, Department of Zoology, University of Wisconsin-Madison, USA
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Increased IP3/Ca2+ signaling compensates depletion of LET-413/DLG-1 in C. elegans epithelial junction assembly. Dev Biol 2008; 327:34-47. [PMID: 19109941 DOI: 10.1016/j.ydbio.2008.11.025] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2008] [Revised: 11/18/2008] [Accepted: 11/19/2008] [Indexed: 12/21/2022]
Abstract
The let-413/scribble and dlg-1/discs large genes are key regulators of epithelial cell polarity in C. elegans and other systems but the mechanism how they organize a circumferential junctional belt around the apex of epithelial cells is not well understood. We report here that IP(3)/Ca(2+) signaling is involved in the let-413/dlg-1 pathway for the establishment of epithelial cell polarity during the development in C. elegans. Using RNAi to interfere with let-413 and dlg-1 gene functions during post-embryogenesis, we discovered a requirement for LET-413 and DLG-1 in the polarization of the spermathecal cells. The spermatheca forms an accordion-like organ through which eggs must enter to complete the ovulation process. LET-413- and DLG-1-depleted animals exhibit failure of ovulation. Consistent with this phenotype, the assembly of the apical junction into a continuous belt fails and the PAR-3 protein and microfilaments are no longer localized asymmetrically. All these defects can be suppressed by mutations in IPP-5, an inositol polyphosphate 5-phosphatase and in ITR-1, an inositol triphosphate receptor, which both are supposed to increase the intracellular Ca(2+) level. Analysis of embryogenesis revealed that IP(3)/Ca(2+) signaling is also required during junction assembly in embryonic epithelia.
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Shapiro L, Love J, Colman DR. Adhesion molecules in the nervous system: structural insights into function and diversity. Annu Rev Neurosci 2007; 30:451-74. [PMID: 17600523 DOI: 10.1146/annurev.neuro.29.051605.113034] [Citation(s) in RCA: 149] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The unparalleled complexity of intercellular connections in the nervous system presents requirements for high levels of both specificity and diversity for the proteins that mediate cell adhesion. Here we describe recent advances toward understanding the molecular mechanisms that underlie adhesive binding, specificity, and diversity for several well-characterized families of adhesion molecules in the nervous system. Although many families of adhesion proteins, including cadherins and immunoglobulin superfamily members, are utilized in neural and nonneural contexts, nervous system-specific diversification mechanisms, such as precisely regulated alternative splicing, provide an important means to enable their function in the complex context of the nervous system.
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Affiliation(s)
- Lawrence Shapiro
- Department of Biochemistry and Molecular Biophysics, 2Edward S. Harkness Eye Institute, Columbia University, New York, New York 10032 USA.
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Cereijido M, Contreras RG, Shoshani L, Flores-Benitez D, Larre I. Tight junction and polarity interaction in the transporting epithelial phenotype. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2007; 1778:770-93. [PMID: 18028872 DOI: 10.1016/j.bbamem.2007.09.001] [Citation(s) in RCA: 108] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2007] [Revised: 08/28/2007] [Accepted: 09/03/2007] [Indexed: 12/21/2022]
Abstract
Development of tight junctions and cell polarity in epithelial cells requires a complex cellular machinery to execute an internal program in response to ambient cues. Tight junctions, a product of this machinery, can act as gates of the paracellular pathway, fences that keep the identity of plasma membrane domains, bridges that communicate neighboring cells. The polarization internal program and machinery are conserved in yeast, worms, flies and mammals, and in cell types as different as epithelia, neurons and lymphocytes. Polarization and tight junctions are dynamic features that change during development, in response to physiological and pharmacological challenges and in pathological situations like infection.
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Affiliation(s)
- Marcelino Cereijido
- Department of Physiology, Biophysics and Neurosciences, CINVESTAV, AP 14-740, México D.F. 07000, México.
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de Guzman Strong C, Wertz PW, Wang C, Yang F, Meltzer PS, Andl T, Millar SE, Ho IC, Pai SY, Segre JA. Lipid defect underlies selective skin barrier impairment of an epidermal-specific deletion of Gata-3. ACTA ACUST UNITED AC 2007; 175:661-70. [PMID: 17116754 PMCID: PMC2064601 DOI: 10.1083/jcb.200605057] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Skin lies at the interface between the complex physiology of the body and the external environment. This essential epidermal barrier, composed of cornified proteins encased in lipids, prevents both water loss and entry of infectious or toxic substances. We uncover that the transcription factor GATA-3 is required to establish the epidermal barrier and survive in the ex utero environment. Analysis of Gata-3 mutant transcriptional profiles at three critical developmental stages identifies a specific defect in lipid biosynthesis and a delay in differentiation. Genomic analysis identifies highly conserved GATA-3 binding sites bound in vivo by GATA-3 in the first intron of the lipid acyltransferase gene AGPAT5. Skin from both Gata-3-/- and previously characterized barrier-deficient Kruppel-like factor 4-/- newborns up-regulate antimicrobial peptides, effectors of innate immunity. Comparison of these animal models illustrates how impairment of the skin barrier by two genetically distinct mechanisms leads to innate immune responses, as observed in the common human skin disorders psoriasis and atopic dermatitis.
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Affiliation(s)
- Cristina de Guzman Strong
- National Human Genome Research Institute and 2National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
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McCrea PD, Park JI. Developmental functions of the P120-catenin sub-family. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2006; 1773:17-33. [PMID: 16942809 DOI: 10.1016/j.bbamcr.2006.06.009] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2006] [Revised: 06/21/2006] [Accepted: 06/26/2006] [Indexed: 01/11/2023]
Abstract
For more than a decade, cell, developmental and cancer investigators have brought about a wide interest in the biology of catenin proteins, an attraction being their varied functions within differing cellular compartments. While the diversity of catenin localizations and roles has been intriguing, it has also posed a challenge to the clear interpretation of loss- or gain-of-function developmental phenotypes. The most deeply studied member of the larger catenin family is beta-catenin, whose contributions span areas including cell adhesion and intracellular signaling/ transcriptional control. More recently, attention has been directed towards p120-catenin, which in conjunction with the p120-catenin sub-family members ARVCF- and delta-catenins, are the subjects of this review. Although the requirement for vertebrate versus invertebrate p120-catenin are at variance, vertebrate p120-catenin sub-family members may each inter-link cadherin, cytoskeletal and gene regulatory functions in embryogenesis and disease.
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Affiliation(s)
- Pierre D McCrea
- Department of Biochemistry and Molecular Biology, Program in Genes and Development, University of Texas MD Anderson Cancer Center, University of Texas Graduate School of Biomedical Science, Houston TX 77030, USA.
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Wang X, Kweon J, Larson S, Chen L. A role for the C. elegans L1CAM homologue lad-1/sax-7 in maintaining tissue attachment. Dev Biol 2005; 284:273-91. [PMID: 16023097 DOI: 10.1016/j.ydbio.2005.05.020] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2004] [Revised: 05/05/2005] [Accepted: 05/18/2005] [Indexed: 12/28/2022]
Abstract
The L1 family of cell adhesion molecules (L1CAMs) is important for neural development. Mutations in one of the human L1CAM genes, L1, can result in several neurological syndromes, the symptoms of which are variably penetrant. The physiological cause of these symptoms, collectively termed CRASH, is not clear. Caenorhabditis elegans animals genetically null for the L1CAM homologue LAD-1, exhibit variably penetrant pleiotropic phenotypes that are similar to the CRASH symptoms; thus the C. elegans lad-1 mutant provides an excellent model system to study how disruption of L1 leads to these abnormalities. These phenotypes include uncoordinated movements, variable embryonic lethality, and abnormal neuronal distribution and axon trajectories. Our analysis revealed that many of these phenotypes are likely a result of tissue detachment.
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Affiliation(s)
- Xuelin Wang
- Department of Genetics, Cell Biology, and Development, The Developmental Biology Center, University of Minnesota, 6-160 Jackson Hall, SE Minneapolis, MN 55455, USA
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