scholarly journals Par protein localization during the early development of Mnemiopsis leidyi suggests different modes of epithelial organization in Metazoa

2018 ◽  
Author(s):  
Miguel Salinas-Saavedra ◽  
Mark Q Martindale
Keyword(s):  
Cell Adhesion ◽  
Cell Polarity ◽  
Protein Localization ◽  
Mnemiopsis Leidyi ◽  
Epithelial Tissue ◽  
Par Proteins ◽  
Pcp Signaling ◽  
Specific Mrnas ◽  
Junctional Complexes ◽  
Cell Cell

ABSTRACTIn bilaterians and cnidarians, embryonic and epithelial cell-polarity are regulated by the interactions between Par proteins, Wnt/PCP signaling pathway, and cell-cell adhesion. Par proteins are highly conserved across Metazoa, including ctenophores. But strikingly, ctenophore genomes lack components of the Wnt/PCP pathway and cell-cell adhesion complexes; raising the question if ctenophore cells are polarized by mechanisms involving Par proteins. Here, by using immunohistochemistry and live-cell imaging overexpression of specific mRNAs, we describe for the first time the subcellular localization of selected Par proteins in blastomeres and epithelial cells during the embryogenesis of the ctenophore Mnemiopsis leidyi. We show that these proteins distribute differently compared to what has been described for other animals, even though they segregate in a host-specific fashion when expressed in cnidarian embryos. This differential localization might be related to the emergence of different junctional complexes during metazoan evolution. Data obtained here challenge the ancestry of the apicobasal cell polarity and raise questions about the homology of epithelial tissue across the Metazoa.

scholarly journals Par protein localization during the early development of Mnemiopsis leidyi suggests different modes of epithelial organization in the metazoa

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Miguel Salinas-Saavedra ◽  
Mark Q Martindale
Keyword(s):  
Cell Adhesion ◽  
Live Cell Imaging ◽  
Protein Localization ◽  
Mnemiopsis Leidyi ◽  
Par Proteins ◽  
Pcp Signaling ◽  
Specific Mrnas ◽  
Junctional Complexes ◽  
First Time ◽  
Cell Cell

In bilaterians and cnidarians, epithelial cell-polarity is regulated by the interactions between Par proteins, Wnt/PCP signaling pathway, and cell-cell adhesion. Par proteins are highly conserved across Metazoa, including ctenophores. But strikingly, ctenophore genomes lack components of the Wnt/PCP pathway and cell-cell adhesion complexes raising the question if ctenophore cells are polarized by mechanisms involving Par proteins. Here, by using immunohistochemistry and live-cell imaging of specific mRNAs, we describe for the first time the subcellular localization of selected Par proteins in blastomeres and epithelial cells during the embryogenesis of the ctenophore Mnemiopsis leidyi. We show that these proteins distribute differently compared to what has been described for other animals, even though they segregate in a host-specific fashion when expressed in cnidarian embryos. This differential localization might be related to the emergence of different junctional complexes during metazoan evolution.

scholarly journals Germ layer specific regulation of cell polarity and adhesion gives insight into the evolution of mesoderm

2017 ◽  
Author(s):  
Miguel Salinas-Saavedra ◽  
Amber Q. Rock ◽  
Mark Q Martindale
Keyword(s):  
Cell Adhesion ◽  
Cell Polarity ◽  
Ectopic Expression ◽  
Par Proteins ◽  
Adhesion System ◽  
Transcription Factor Genes ◽  
Epithelial Structure ◽  
Specific Mrnas ◽  
Specific Regulation ◽  
Insight Into

AbstractIn triploblastic animals, Par-proteins regulate cell-polarity and adherens junctions of both ectodermal and endodermal epithelia. But, in embryos of the diploblastic cnidarian Nematostella vectensis, Par-proteins are degraded in all cells in the bifunctional gastrodermal epithelium. Using immunohistochemistry, CRISPR/Cas9 mutagenesis, and overexpression of specific mRNAs, we describe the functional association between Par-proteins, ß-catenin, and snail transcription factor genes in N. vectensis embryos. We demonstrate that the aPKC/Par complex regulates the localization of ß-catenin in the ectoderm by stabilizing its role in cell-adhesion, and that endomesodermal epithelial cells are organized by a different cell-adhesion system than that of overlying ectoderm. We also show that ectopic expression of snail genes, which are expressed in mesodermal derivatives in bilaterians, are sufficient to downregulate Par-proteins and translocate ß-catenin from the junctions to the cytoplasm in ectodermal cells. These data provide molecular insight into the evolution of epithelial structure and distinct mesodermal tissue in metazoan embryos.

scholarly journals CLAMP/Spef1 regulates planar cell polarity signaling and asymmetric microtubule accumulation in the Xenopus ciliated epithelia

2018 ◽  
Vol 217 (5) ◽  
pp. 1633-1641 ◽  
Author(s):  
Sun K. Kim ◽  
Siwei Zhang ◽  
Michael E. Werner ◽  
Eva J. Brotslaw ◽  
Jennifer W. Mitchell ◽  
...  
Keyword(s):  
Cell Division ◽  
Epithelial Cells ◽  
Cell Signaling ◽  
Cell Polarity ◽  
Planar Cell Polarity ◽  
Protein Localization ◽  
Apical Cell ◽  
Cell Cortex ◽  
Pcp Signaling ◽  
Cell Cell

Most epithelial cells polarize along the axis of the tissue, a feature known as planar cell polarity (PCP). The initiation of PCP requires cell–cell signaling via the noncanonical Wnt/PCP pathway. Additionally, changes in the cytoskeleton both facilitate and reflect this polarity. We have identified CLAMP/Spef1 as a novel regulator of PCP signaling. In addition to decorating microtubules (MTs) and the ciliary rootlet, a pool of CLAMP localizes at the apical cell cortex. Depletion of CLAMP leads to the loss of PCP protein asymmetry, defects in cilia polarity, and defects in the angle of cell division. Additionally, depletion of CLAMP leads to a loss of the atypical cadherin-like molecule Celrs2, suggesting that CLAMP facilitates the stabilization of junctional interactions responsible for proper PCP protein localization. Depletion of CLAMP also affects the polarized organization of MTs. We hypothesize that CLAMP facilitates the establishment of cell polarity and promotes the asymmetric accumulation of MTs downstream of the establishment of proper PCP.

(Tissue) P systems with cell polarity

2009 ◽  
Vol 19 (6) ◽  
pp. 1141-1160 ◽  
Author(s):  
DANIELA BESOZZI ◽  
NADIA BUSI ◽  
PAOLO CAZZANIGA ◽  
CLAUDIO FERRETTI ◽  
ALBERTO LEPORATI ◽  
...  
Keyword(s):  
Cell Polarity ◽  
Formal System ◽  
Cell Junctions ◽  
P Systems ◽  
Intestinal Lumen ◽  
Epithelial Tissue ◽  
Specific Cell ◽  
Formal Property ◽  
Intestinal Epithelial ◽  
Cell Cell

We consider the structure of the intestinal epithelial tissue and of cell–cell junctions as the biological model inspiring a new class of P systems. First we define the concept of cell polarity, a formal property derived from epithelial cells, which present morphologically and functionally distinct regions of the plasma membrane. Then we show two preliminary results for this new model of computation: on the theoretical side, we show that P systems with cell polarity are computationally (Turing) complete; on the modelling side, we show that the transepithelial movement of glucose from the intestinal lumen into the blood can be described by such a formal system. Finally, we define tissue P systems with cell polarity, where each cell has fixed connections to the neighbouring cells and to the environment, according to both the cell polarity and specific cell–cell junctions.

scholarly journals Neural Cell Adhesion Molecule (N-CAM) Is Required for Cell Type Segregation and Normal Ultrastructure in Pancreatic Islets

1999 ◽  
Vol 144 (2) ◽  
pp. 325-337 ◽  
Author(s):  
Farzad Esni ◽  
Inge-Bert Täljedal ◽  
Anne-Karina Perl ◽  
Harold Cremer ◽  
Gerhard Christofori ◽  
...  
Keyword(s):  
Cell Adhesion ◽  
Pancreatic Islets ◽  
Cell Polarity ◽  
Adhesion Molecule ◽  
Islet Cell ◽  
Cell Adhesion Molecule ◽  
Cell Junctions ◽  
Cell Type ◽  
Deficient Mice ◽  
Cell Cell

Classical cell dissociation/reaggregation experiments with embryonic tissue and cultured cells have established that cellular cohesiveness, mediated by cell adhesion molecules, is important in determining the organization of cells within tissue and organs. We have employed N-CAM-deficient mice to determine whether N-CAM plays a functional role in the proper segregation of cells during the development of islets of Langerhans. In N-CAM-deficient mice the normal localization of glucagon-producing α cells in the periphery of pancreatic islets is lost, resulting in a more randomized cell distribution. In contrast to the expected reduction of cell–cell adhesion in N-CAM-deficient mice, a significant increase in the clustering of cadherins, F-actin, and cell–cell junctions is observed suggesting enhanced cadherin-mediated adhesion in the absence of proper N-CAM function. These data together with the polarized distribution of islet cell nuclei and Na+/K+-ATPase indicate that islet cell polarity is also affected. Finally, degranulation of β cells suggests that N-CAM is required for normal turnover of insulin-containing secretory granules. Taken together, our results confirm in vivo the hypothesis that a cell adhesion molecule, in this case N-CAM, is required for cell type segregation during organogenesis. Possible mechanisms underlying this phenomenon may include changes in cadherin-mediated adhesion and cell polarity.

scholarly journals Formin-mediated actin polymerization at cell–cell junctions stabilizes E-cadherin and maintains monolayer integrity during wound repair

2016 ◽  
Vol 27 (18) ◽  
pp. 2844-2856 ◽  
Author(s):  
Megha Vaman Rao ◽  
Ronen Zaidel-Bar
Keyword(s):  
Cell Adhesion ◽  
Wound Repair ◽  
Actin Polymerization ◽  
Cell Junctions ◽  
Epithelial Tissue ◽  
Collective Cell Migration ◽  
Epithelial Junctions ◽  
Major Factors ◽  
E Cadherin ◽  
Cell Cell

Cadherin-mediated cell–cell adhesion is required for epithelial tissue integrity in homeostasis, during development, and in tissue repair. E-cadherin stability depends on F-actin, but the mechanisms regulating actin polymerization at cell–cell junctions remain poorly understood. Here we investigated a role for formin-mediated actin polymerization at cell–cell junctions. We identify mDia1 and Fmnl3 as major factors enhancing actin polymerization and stabilizing E-cadherin at epithelial junctions. Fmnl3 localizes to adherens junctions downstream of Src and Cdc42 and its depletion leads to a reduction in F-actin and E-cadherin at junctions and a weakening of cell–cell adhesion. Of importance, Fmnl3 expression is up-regulated and junctional localization increases during collective cell migration. Depletion of Fmnl3 or mDia1 in migrating monolayers results in dissociation of leader cells and impaired wound repair. In summary, our results show that formin activity at epithelial cell–cell junctions is important for adhesion and the maintenance of epithelial cohesion during dynamic processes, such as wound repair.

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