Can 1000 Reviews Be Wrong? Actin, α-Catenin, and Adherens Junctions

Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
Cell (Impact Factor: 32.24). 01/2006; 123(5):769-72. DOI: 10.1016/j.cell.2005.11.009
Source: PubMed

ABSTRACT Coupling between cell adhesion and the actin cytoskeleton is thought to require a stable link between the cadherin-catenin complex and actin that is mediated by alpha-catenin. In this issue of Cell, the Weis and Nelson groups call this static model into question, showing that alpha-catenin can directly regulate actin dynamics (Drees et al., 2005 and Yamada et al., 2005).

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    • "Not only is the cadherin family member E-cadherin responsible for compaction of the embryo, but it is also a key organizer of adhesion junctions in epithelial tissue [10–12]. Cadherins which are located at the plasma membrane are intracellularly connected to the actin cytoskeleton via special proteins like catenins [13]. Gap junction and cell adhesion proteins are also associated with each other and exhibit a functional cooperation to increase the stability of cell-cell and cell-extracellular matrix structures [14]. "
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    ABSTRACT: The aim of this study was to investigate the effects of experimentally induced diabetes on (a) germ cells, (b) in vitro fertilization (IVF) success rate, and (c) gap junction and cell adhesion molecule gene and protein expressions during the early blastocyst period. Germ cells were obtained from healthy and diabetic rats, analyzed for number, motility, and morphology, and used for IVF. After reaching the early blastocyst stage, the expressions of genes encoding gap junction proteins and cell adhesion molecules were analyzed by quantitative RT-PCR. Histomorphologically and immunohistochemically analyses were also performed. Diabetes significantly affected sperm number and motility and the development of oocytes. Gene expressions of β -catenin and connexin family members and protein expressions of E-cadherin and connexin-43 significantly decreased in groups including germ cells isolated from diabetic rats. Connective tissue growth factor expression increased in groups that included sperm cells isolated from diabetic male rats, whereas mucin-1 expression increased in the group that included oocytes isolated from diabetic female rats paired with sperm cells isolated from healthy male rats. In summary, experimentally induced diabetes was found to influence gap junctions, cell adhesion molecules, and associated proteins which all have important roles in germ cell maturation, fertilization, and development.
    Journal of Diabetes Research 03/2013; 2013:603813. DOI:10.1155/2013/603813 · 2.16 Impact Factor
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    • "These morphogenetic events underlie shape changes and/or movements, mostly dependent on an intact actomyosin cytoskeleton (a network of actin filaments cross-linked with myosin II molecular motors). Actin filaments and myosin II generate tensile forces in individual cells that are transmitted across an entire tissue through adherens junctions (AJs) [1], [2]. During epithelial morphogenesis apical constriction is generated by this type of forces and results in a reduction of the cells' apical domain [3]. "
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    ABSTRACT: Coordination of apical constriction in epithelial sheets is a fundamental process during embryogenesis. Here, we show that DRhoGEF2 is a key regulator of apical pulsation and constriction of amnioserosal cells during Drosophila dorsal closure. Amnioserosal cells mutant for DRhoGEF2 exhibit a consistent decrease in amnioserosa pulsations whereas overexpression of DRhoGEF2 in this tissue leads to an increase in the contraction time of pulsations. We probed the physical properties of the amnioserosa to show that the average tension in DRhoGEF2 mutant cells is lower than wild-type and that overexpression of DRhoGEF2 results in a tissue that is more solid-like than wild-type. We also observe that in the DRhoGEF2 overexpressing cells there is a dramatic increase of apical actomyosin coalescence that can contribute to the generation of more contractile forces, leading to amnioserosal cells with smaller apical surface than wild-type. Conversely, in DRhoGEF2 mutants, the apical actomyosin coalescence is impaired. These results identify DRhoGEF2 as an upstream regulator of the actomyosin contractile machinery that drives amnioserosa cells pulsations and apical constriction.
    PLoS ONE 09/2011; 6(9):e23964. DOI:10.1371/journal.pone.0023964 · 3.23 Impact Factor
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    • "Cell shape is also influenced by the mechanical tension created by the actin cytoskeleton. Adhesive and cortical tensions are not independent but are dynamically regulated through the interaction of E-cadherin and the actin cytoskeleton [9]. In contrast, desmosomes form strong adhesions that are linked to the intermediate filament system and are essential for tissue integrity [10], [11]. "
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    ABSTRACT: Cell shape and tissue architecture are controlled by changes to junctional proteins and the cytoskeleton. How tissues control the dynamics of adhesion and cytoskeletal tension is unclear. We have studied epithelial tissue architecture using 3D culture models and found that adult primary prostate epithelial cells grow into hollow acinus-like spheroids. Importantly, when co-cultured with stroma the epithelia show increased lateral cell adhesions. To investigate this mechanism further we aimed to: identify a cell line model to allow repeatable and robust experiments; determine whether or not epithelial adhesion molecules were affected by stromal culture; and determine which stromal signalling molecules may influence cell adhesion in 3D epithelial cell cultures. The prostate cell line, BPH-1, showed increased lateral cell adhesion in response to stroma, when grown as 3D spheroids. Electron microscopy showed that 9.4% of lateral membranes were within 20 nm of each other and that this increased to 54% in the presence of stroma, after 7 days in culture. Stromal signalling did not influence E-cadherin or desmosome RNA or protein expression, but increased E-cadherin/actin co-localisation on the basolateral membranes, and decreased paracellular permeability. Microarray analysis identified several growth factors and pathways that were differentially expressed in stroma in response to 3D epithelial culture. The upregulated growth factors TGFβ2, CXCL12 and FGF10 were selected for further analysis because of previous associations with morphology. Small molecule inhibition of TGFβ2 signalling but not of CXCL12 and FGF10 signalling led to a decrease in actin and E-cadherin co-localisation and increased paracellular permeability. In 3D culture models, paracrine stromal signals increase epithelial cell adhesion via adhesion/cytoskeleton interactions and TGFβ2-dependent mechanisms may play a key role. These findings indicate a role for stroma in maintaining adult epithelial tissue morphology and integrity.
    PLoS ONE 04/2011; 6(4):e18796. DOI:10.1371/journal.pone.0018796 · 3.23 Impact Factor
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