scholarly journals Interactions of a hemidesmosome component and actinin family members

2001 ◽  
Vol 114 (23) ◽  
pp. 4197-4206
Author(s):  
Annette M. Gonzalez ◽  
Carol Otey ◽  
Magnus Edlund ◽  
Jonathan C. R. Jones
Keyword(s):  
Epithelial Cells ◽  
Family Members ◽  
Adherens Junction ◽  
Cell Contact ◽  
Yeast Two Hybrid ◽  
Ef Hand ◽  
Adherens Junction Proteins ◽  
Two Hybrid ◽  
Junction Proteins ◽  
Cell Cell

Hemidesmosomes are multimeric protein complexes that attach epithelial cells to their underlying matrix and serve as cell surface anchorage sites for the keratin cytoskeleton. Two hemidesmosome components, the α6β4 integrin heterodimer and a human autoantigen termed BP180, are transmembrane proteins that link the extracellular matrix to the keratin network in cells. Here, we report that actinin-4, an actin-bundling protein, is a potential binding partner for BP180. Using yeast two-hybrid, we have mapped the binding site for BP180 to the C-terminal region of actinin-4. This site contains two EF-hand, Ca2+ regulation domains and shares 87% sequence homology with the same region in actinin-1. Consistent with this, BP180 can bind actinin-1 in both the yeast two-hybrid assay and in immunoprecipitation assays. To determine whether the EF-hand domain is a consensus binding sequence for BP180, we tested whether other proteins with this domain bind BP180. None of the proteins tested including calmodulin, with 4 EF-hand domains, and myosin regulatory light chain, with 1 EF-hand domain, interacts with BP180 in yeast two-hybrid system and immunoprecipitation studies, suggesting that the interaction between BP180 and actinin family members is specific. We have compared the distribution of actinin-1 and actinin-4 with that of BP180 in MCF-10A and pp126 cells. Surprisingly, BP180 localizes not only to sites of cell-substratum interaction, but is also present at sites of cell-cell contacts where it co-distributes with both actinin-1 and actinin-4 as well as other adherens junction proteins. In oral tissues, BP180 is present along the basement membrane and at cell-cell contact sites in basal epithelial cells where it co-distributes with adherens junction proteins. Since BP180 antibodies inhibit association of junction proteins at sites of cell-cell contact in oral keratinocytes, these results suggest that BP180 may play a role in establishing cell-cell interactions. We discuss a role for BP180 in crosstalk between cell-matrix and cell-cell junctions.

scholarly journals PLAC-24 Is a Cytoplasmic Dynein-Binding Protein That Is Recruited to Sites of Cell-Cell Contact

2002 ◽  
Vol 13 (5) ◽  
pp. 1722-1734 ◽  
Author(s):  
Sher Karki ◽  
Lee A. Ligon ◽  
Jamison DeSantis ◽  
Mariko Tokito ◽  
Erika L. F. Holzbaur
Keyword(s):  
Epithelial Cells ◽  
Recent Observation ◽  
Polyclonal Antibodies ◽  
Adherens Junction ◽  
Cytoplasmic Dynein ◽  
Cell Contact ◽  
Dynein Intermediate Chain ◽  
Cellular Cytoskeleton ◽  
Cell Cell ◽  
Intermediate Chain

We screened for polypeptides that interact specifically with dynein and identified a novel 24-kDa protein (PLAC-24) that binds directly to dynein intermediate chain (DIC). PLAC-24 is not a dynactin subunit, and the binding of PLAC-24 to the dynein intermediate chain is independent of the association between dynein and dynactin. Immunocytochemistry using PLAC-24–specific polyclonal antibodies revealed a punctate perinuclear distribution of the polypeptide in fibroblasts and isolated epithelial cells. However, as epithelial cells in culture make contact with adjacent cells, PLAC-24 is specifically recruited to the cortex at sites of contact, where the protein colocalizes with components of the adherens junction. Disruption of the cellular cytoskeleton with latrunculin or nocodazole indicates that the localization of PLAC-24 to the cortex is dependent on intact actin filaments but not on microtubules. Overexpression of β-catenin also leads to a loss of PLAC-24 from sites of cell-cell contact. On the basis of these data and the recent observation that cytoplasmic dynein is also localized to sites of cell-cell contact in epithelial cells, we propose that PLAC-24 is part of a multiprotein complex localized to sites of intercellular contact that may function to tether microtubule plus ends to the actin-rich cellular cortex.

2,2′,4,4′,5,5′-Hexachlorobiphenyl (PCB 153) induces degradation of adherens junction proteins and inhibits β-catenin-dependent transcription in liver epithelial cells

Toxicology ◽  
2009 ◽  
Vol 260 (1-3) ◽  
pp. 104-111 ◽  
Author(s):  
P. Šimečková ◽  
J. Vondráček ◽  
J. Procházková ◽  
A. Kozubík ◽  
P. Krčmář ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Adherens Junction ◽  
Liver Epithelial Cells ◽  
Adherens Junction Proteins ◽  
Junction Proteins

scholarly journals Integrin regulation of cell-cell adhesion during epithelial tubule formation

2001 ◽  
Vol 114 (5) ◽  
pp. 941-952 ◽  
Author(s):  
G.K. Ojakian ◽  
D.R. Ratcliffe ◽  
R. Schwimmer
Keyword(s):  
Extracellular Matrix ◽  
Adherens Junction ◽  
Cell Junctions ◽  
Junctional Complex ◽  
Tubule Formation ◽  
Epithelial Remodeling ◽  
Adherens Junction Proteins ◽  
Junction Proteins ◽  
E Cadherin ◽  
Cell Cell

The extracellular matrix plays an important role in regulation of epithelial development and organization. To determine more precisely the function of extracellular matrix in this process, the initial steps in collagen-mediated formation of epithelial tubules were studied using a model cell culture system. Previous studies have demonstrated that incubation of Madin-Darby canine kidney (MDCK) epithelial cells with a collagen gel overlay induces (beta)1 integrin-regulated epithelial remodeling accompanied by extensive cell rearrangements and formation of epithelial tubules. During epithelial remodeling there was extensive disruption of the epithelial junctional complex. Progressive opening of tight junctions was observed over 8 hours using transepithelial resistance measurements and immunofluorescence microscopy demonstrated that tight and adherens junction proteins were dispersed throughout the apical and basolateral membranes. Junction complex disruption allowed the formation of apical cell extensions and subsequent migration of selected cell sheets from the epithelial monolayer. Confocal microscopy demonstrated the presence of adherens junction (E-cadherin, (alpha)-catenin, (beta)-catenin, plakoglobin) and desmosomal (desmoplakin-1/2, plakoglobin) proteins on, and within, cell extensions demonstrating that cell junctions had undergone considerable disassembly. However, groups of cell extensions appeared to be associated by E-cadherin/catenin-mediated interactions. Association of E-cadherin/catenin complexes with the epithelial cytoskeleton was analyzed by differential detergent extraction. SDS-PAGE and immunoblot analysis demonstrated that adherens junction proteins were primarily cytoskeleton-associated in control cells. During integrin-regulated remodeling, there was a progressive reduction in the interaction of adherens junction proteins with the cytoskeleton suggesting that they play an important role in the maintenance of epithelial integrity. Since loss of transepithelial electrical resistance and disruption of junctional complexes were inhibited by an antifunctional integrin antibody, we propose that activation of integrin signaling pathways regulate junctional complex stability, cell-cell interactions and cell migration. These observations provide evidence that integrin-regulated MDCK epithelial tubule formation can serve as a model system for studying rearrangements of epithelial sheets which occur during development.

ralGDS family members interact with the effector loop of ras p21

1994 ◽  
Vol 14 (11) ◽  
pp. 7483-7491
Author(s):  
A Kikuchi ◽  
S D Demo ◽  
Z H Ye ◽  
Y W Chen ◽  
L T Williams
Keyword(s):  
Hybrid System ◽  
Family Members ◽  
Dominant Negative Mutant ◽  
Yeast Two Hybrid ◽  
Amino Acid Homology ◽  
Yeast Two Hybrid System ◽  
Ras P21 ◽  
Two Hybrid ◽  
Interacting Domain

Using a yeast two-hybrid system, we identified a novel protein which interacts with ras p21. This protein shares 69% amino acid homology with ral guanine nucleotide dissociation stimulator (ralGDS), a GDP/GTP exchange protein for ral p24. We designated this protein RGL, for ralGDS-like. Using the yeast two-hybrid system, we found that an effector loop mutant of ras p21 was defective in interacting with the ras p21-interacting domain of RGL, suggesting that this domain binds to ras p21 through the effector loop of ras p21. Since ralGDS contained a region highly homologous with the ras p21-interacting domain of RGL, we examined whether ralGDS could interact with ras p21. In the yeast two-hybrid system, ralGDS failed to interact with an effector loop mutant of ras p21. In insect cells, ralGDS made a complex with v-ras p21 but not with a dominant negative mutant of ras p21. ralGDS interacted with the GTP-bound form of ras p21 but not with the GDP-bound form in vitro. ralGDS inhibited both the GTPase-activating activity of the neurofibromatosis gene product (NF1) for ras p21 and the interaction of Raf with ras p21 in vitro. These results demonstrate that ralGDS specifically interacts with the active form of ras p21 and that ralGDS can compete with NF1 and Raf for binding to the effector loop of ras p21. Therefore, ralGDS family members may be effector proteins of ras p21 or may inhibit interactions between ras p21 and its effectors.

scholarly journals Drosophila p120catenin plays a supporting role in cell adhesion but is not an essential adherens junction component

2003 ◽  
Vol 160 (3) ◽  
pp. 433-449 ◽  
Author(s):  
Steven H. Myster ◽  
Robert Cavallo ◽  
Charles T. Anderson ◽  
Donald T. Fox ◽  
Mark Peifer
Keyword(s):  
Cell Adhesion ◽  
Adherens Junctions ◽  
Adherens Junction ◽  
Null Alleles ◽  
Juxtamembrane Region ◽  
Genes Encoding ◽  
Positive Modulator ◽  
Adherens Junction Proteins ◽  
Junction Structure ◽  
Junction Proteins

Cadherin–catenin complexes, localized to adherens junctions, are essential for cell–cell adhesion. One means of regulating adhesion is through the juxtamembrane domain of the cadherin cytoplasmic tail. This region is the binding site for p120, leading to the hypothesis that p120 is a key regulator of cell adhesion. p120 has also been suggested to regulate the GTPase Rho and to regulate transcription via its binding partner Kaiso. To test these hypothesized functions, we turned to Drosophila, which has only a single p120 family member. It localizes to adherens junctions and binds the juxtamembrane region of DE-cadherin (DE-cad). We generated null alleles of p120 and found that mutants are viable and fertile and have no substantial changes in junction structure or function. However, p120 mutations strongly enhance mutations in the genes encoding DE-cadherin or Armadillo, the β-catenin homologue. Finally, we examined the localization of p120 during embryogenesis. p120 localizes to adherens junctions, but its localization there is less universal than that of core adherens junction proteins. Together, these data suggest that p120 is an important positive modulator of adhesion but that it is not an essential core component of adherens junctions.

Ectopic expression of gastrokine 1 in gastric cancer cells up-regulates tight and adherens junction proteins network

2015 ◽  
Vol 211 (8) ◽  
pp. 577-583 ◽  
Author(s):  
Emilia Rippa ◽  
Filomena Altieri ◽  
Chiara Stella Di Stadio ◽  
Giuseppina Miselli ◽  
Annalisa Lamberti ◽  
...  
Keyword(s):  
Gastric Cancer ◽  
Cancer Cells ◽  
Ectopic Expression ◽  
Adherens Junction ◽  
Gastric Cancer Cells ◽  
Gastrokine 1 ◽  
Adherens Junction Proteins ◽  
Junction Proteins

scholarly journals Regulation of myosin activation during cell–cell contact formation by Par3-Lgl antagonism: entosis without matrix detachment

2012 ◽  
Vol 23 (11) ◽  
pp. 2076-2091 ◽  
Author(s):  
Qingwen Wan ◽  
Jing Liu ◽  
Zhen Zheng ◽  
Huabin Zhu ◽  
Xiaogang Chu ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Molecular Mechanisms ◽  
Myosin Ii ◽  
Coiled Coil ◽  
Host Cells ◽  
Cell Contact ◽  
Contact Formation ◽  
Cell Internalization ◽  
Mammary Gland Epithelial Cells ◽  
Cell Cell

Cell–cell contact formation following cadherin engagement requires actomyosin contraction along the periphery of cell–cell contact. The molecular mechanisms that regulate myosin activation during this process are not clear. In this paper, we show that two polarity proteins, partitioning defective 3 homologue (Par3) and mammalian homologues of Drosophila Lethal (2) Giant Larvae (Lgl1/2), antagonize each other in modulating myosin II activation during cell–cell contact formation in Madin-Darby canine kidney cells. While overexpression of Lgl1/2 or depletion of endogenous Par3 leads to enhanced myosin II activation, knockdown of Lgl1/2 does the opposite. Intriguingly, altering the counteraction between Par3 and Lgl1/2 induces cell–cell internalization during early cell–cell contact formation, which involves active invasion of the lateral cell–cell contact underneath the apical-junctional complexes and requires activation of the Rho–Rho-associated, coiled-coil containing protein kinase (ROCK)–myosin pathway. This is followed by predominantly nonapoptotic cell-in-cell death of the internalized cells and frequent aneuploidy of the host cells. Such effects are reminiscent of entosis, a recently described process observed when mammary gland epithelial cells were cultured in suspension. We propose that entosis could occur without matrix detachment and that overactivation of myosin or unbalanced myosin activation between contacting cells may be the driving force for entosis in epithelial cells.

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