The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Yoshimi Takai - One of the best experts on this subject based on the ideXlab platform.
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novel role of nectin implication in the co localization of jam a and claudin 1 at the same Cell Cell Adhesion membrane domain
Genes to Cells, 2008Co-Authors: Kaori Kuramitsu, Wataru Ikeda, Naoya Inoue, Yoshiyuki Tamaru, Yoshimi TakaiAbstract:Tight junctions (TJs) are formed at the apical side of adherens junctions (AJs) in epithelial Cells. Major Cell Adhesion molecules (CAMs) at TJs are JAM and claudin, whereas major CAMs at AJs are nectin and cadherin. We previously showed that nectin initially forms Cell–Cell Adhesion and then recruits cadherin to the nectin-based Cell–Cell Adhesion sites to form AJs, followed by the recruitment of JAM and claudin to the apical side of AJs to form TJs. We investigated the roles of nectin in the formation of TJs by expressing various combinations of CAMs in L fibroblasts with no TJs or AJs. Co-expression of one of the AJ CAMs and one of the TJ CAMs formed two separate Cell–Cell Adhesion membrane domains (CAMDs). Co-expression of nectin-3 and E-cadherin formed the same CAMD, but co-expression of JAM-A and claudin-1 did not form the same CAMD. Co-expression of JAM-A and claudin-1 with nectin-3, but not E-cadherin, made them form the same CAMD, which was separated from the nectin-based CAMD. Nectin-3 required afadin, a nectin- and F-actin-binding protein, for this ability. In conclusion, nectin plays a novel role in the co-localization of JAM and claudin at the same CAMD.
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involvement of nectin in inactivation of integrin αvβ3 after the establishment of Cell Cell Adhesion
Journal of Biological Chemistry, 2008Co-Authors: Yasuhisa Sakamoto, Hisakazu Ogita, Hitomi Komura, Yoshimi TakaiAbstract:Abstract Integrin plays an essential role in the formation of Cell-matrix junctions and is also involved in the fundamental Cellular functions. In the process of the formation of Cell-Cell junctions, an immunoglobulin-like Cell-Cell Adhesion molecule nectin initially trans-interacts together and promotes the formation of adherens junctions (AJs) cooperatively with another Cell-Cell Adhesion molecule cadherin. The activation of integrin αvβ3 is critically necessary for this nectin-induced formation of AJs. However, after the establishment of AJs, integrin αvβ3 becomes inactive and retains the association with nectin at AJs. The molecular mechanism of this dynamic regulation of integrin αvβ3 during the formation of AJs remains unclear. We found here that the expression of phosphatidylinositol-phosphate kinase type Iγ90 (PIPKIγ90), which is involved in the regulation of integrin activation, in Madin-Darby canine kidney Cells, preferentially reversed the inactivation of integrin αvβ3 at Cell-Cell Adhesion sites and partially disrupted E-cadherin-based AJs. The activation of PIPKIγ is correlated with its phosphorylation state. The tyrosine phosphatase protein-tyrosine phosphatase μ (PTPμ) effectively dephosphorylated PIPKIγ and thus canceled the PIPKIγ-dependent activation of integrin αvβ3 by blocking the interaction of integrin αvβ3 with talin. Moreover, PTPμ associated with nectin, and its phosphatase activity was enhanced by the trans-interaction of nectin, leading to the decrease in PIPKIγ90 phosphorylation. Therefore, the trans-interaction of nectin essentially functions in the inactivation of integrin at AJs through the PTPμ-induced inactivation of PIPKIγ.
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common signaling pathway is used by the trans interaction of necl 5 tage4 pvr cd155 and nectin and of nectin and nectin during the formation of Cell Cell Adhesion
Cancer Science, 2005Co-Authors: Tatsuhiro Sato, Kenji Irie, Takako Ooshio, Ryoko Okamoto, Naoyuki Fujita, Yoshimi TakaiAbstract:Nectin is a Ca2+-independent Ig-like Cell–Cell Adhesion molecule that forms homo- and hetero-trans-dimers (trans-interaction). Nectin first forms Cell–Cell Adhesions and then recruits cadherin to the nectin-based Cell–Cell Adhesion sites to form AJ cooperatively with cadherin. In addition, the trans-interaction of nectin and nectin induces the activation of Cdc42 and Rac small G proteins, which enhances the formation of AJ. The activation of Cdc42 and Rac by the trans-interaction of nectin and nectin is mediated by c-Src, another small G protein, Rap1, a Cdc42-GEF, FRG, and a Rac-GEF, Vav2. Necl-5/Tage4/PVR/CD155 is another Ca2+-independent Ig-like molecule, which does not homophilically trans-interact, but heterophilically trans-interacts with nectin-3, one member of the nectin family. We show here that the trans-interaction of Necl-5 and nectin-3 bidirectionally induces the activation of Cdc42 and Rac. Similarly to the activation of Cdc42 and Rac by the trans-interaction of nectin and nectin, the trans-interaction of Necl-5 and nectin-3 first recruits and activates c-Src at the Necl-5/nectin-3-based Cell–Cell contact sites. c-Src then phosphorylates FRG and Vav2, and the tyrosine-phosphorylated FRG and Vav2 are recruited to the Necl-5/nectin-3-based Cell–Cell contact sites. The trans-interaction of Necl-5 and nectin-3 also activates Rap1 through C3G, a Rap-GEF, and this activation of Rap1 is required for the activation of Cdc42 and Rac. These results indicate that the trans-interactions of Necl-5 and nectin-3 and of nectin and nectin induce the activation of Cdc42 and Rac through the common signaling molecules c-Src, Rap1, FRG, and Vav2. (Cancer Sci 2005; 96: 578 –589)
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nectin like molecule 1 tsll1 syncam3 a neural tissue specific immunoglobulin like Cell Cell Adhesion molecule localizing at non junctional contact sites of presynaptic nerve terminals axons and glia Cell processes
Journal of Cell Science, 2005Co-Authors: Shigeki Kakunaga, Wataru Ikeda, Shinsuke Itoh, Toshihisa Ohtsuka, Akira Mizoguchi, Maki Deguchitawarada, Yoshimi TakaiAbstract:Nectins are Ca2+-independent immunoglobulin-like Cell-Cell Adhesion molecules and comprise a family of four members. At the mossy fiber terminals of hippocampus, nectin-1 and nectin-3 localize at the presynaptic and postsynaptic sides of synaptic junctions, respectively, and their trans-interactions play a role in formation of synapses in cooperation with N-cadherin. Nectins are associated with the actin cytoskeleton through afadin, a nectin- and actin-filament-binding protein. Five nectin-like molecules (Necls) which have domain structures similar to those of nectins have been identified and here we characterize Necl-1/TSLL1/SynCAM3, from now on referred to as Necl-1. Tissue distribution analysis showed that Necl-1 was specifically expressed in the neural tissue. Immunofluorescence and immunoelectron microscopy revealed that Necl-1 localized at the contact sites among axons, their terminals, and glia Cell processes that cooperatively formed synapses, axon bundles and myelinated axons. Necl-1 showed Ca2+-independent homophilic Cell-Cell Adhesion activity. It furthermore showed Ca2+-independent heterophilic Cell-Cell Adhesion activity with Necl-2/IGSF4/RA175/SgIGSF/TSLC1/SynCAM1 from now on referred to as Necl-2, nectin-1 and nectin-3, but not with Necl-5 or nectin-2. The C-terminal cytoplasmic region of Necl-1 did not bind afadin but bound membrane-associated guanylate kinase subfamily members that contain the L27 domain, including Dlg3, Pals2 and CASK. These results indicate that Necl-1 is a neural-tissue-specific Ca2+-independent immunoglobulin-like Cell-Cell Adhesion molecule which potentially has membrane-associated guanylate kinase subfamily member-binding activity and localizes at the non-junctional Cell-Cell contact sites.
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involvement of lmo7 in the association of two Cell Cell Adhesion molecules nectin and e cadherin through afadin and α actinin in epithelial Cells
Journal of Biological Chemistry, 2004Co-Authors: Takako Ooshio, Kenji Irie, Koji Morimoto, Atsunori Fukuhara, Toshio Imai, Yoshimi TakaiAbstract:Abstract Nectins are Ca2+-independent immunoglobulin-like Cell-Cell Adhesion molecules that are involved in formation of cadherin-based adherens junctions (AJs). The nectin-based Cell-Cell Adhesion induces activation of Cdc42 and Rac small G proteins, which eventually enhances the formation of AJs through reorganization of the actin cytoskeleton. Although evidence has accumulated that nectins recruit cadherins to the nectin-based Cell-Cell Adhesion sites through their cytoplasm-associated proteins, afadin and catenins, it is not fully understood how nectins are physically associated with cadherins. Here we identified a rat counterpart of the human LIM domain only 7 (LMO7) as an afadin- and α-actinin-binding protein. Rat LMO7 has two splice variants, LMO7a and LMO7b, consisting of 1,729 and 1,395 amino acids, respectively. LMO7 has calponin homology, PDZ, and LIM domains. Western blotting revealed that LMO7 was expressed ubiquitously in various rat tissues. Immunofluorescence and immunoelectron microscopy revealed that LMO7 localized at Cell-Cell AJs, where afadin localized, in epithelial Cells of rat gallbladder. In addition, LMO7 localized at the cytoplasmic faces of apical membranes in the same epithelial Cells. We furthermore revealed that LMO7 bound α-actinin, an actin filament-bundling protein, which bound to α-catenin. Immunoprecipitation analysis revealed that LMO7 was associated with both the nectin-afadin and E-cadherin-catenin systems. LMO7 was assembled at the Cell-Cell Adhesion sites after both the nectin-afadin and E-cadherin-catenin systems had been assembled. These results indicate that LMO7 is an afadin- and α-actinin-binding protein that connects the nectin-afadin and E-cadherin-catenin systems through α-actinin.
James W Nelson - One of the best experts on this subject based on the ideXlab platform.
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adenomatous polyposis coli regulates endothelial Cell migration independent of roles in β catenin signaling and Cell Cell Adhesion
Molecular Biology of the Cell, 2010Co-Authors: Elizabeth S Harris, James W NelsonAbstract:Adenomatous polyposis coli (APC), a tumor suppressor commonly mutated in cancer, is a cytoskeletal organizer for Cell migration and a scaffold for GSK3β/CKI-mediated phosphorylation and degradation of the Wnt effector β-catenin. It remains unclear whether these different APC functions are coupled, or independently regulated and localized. In primary endothelial Cells, we show that GSK3β/CKI-phosphorylated APC localizes to microtubule-dependent clusters at the tips of membrane extensions. Loss of GSK3β/CKI-phosphorylated APC from these clusters correlates with a decrease in Cell migration. GSK3β/CKI-phosphorylated APC and β-catenin at clusters is degraded rapidly by the proteasome, but inhibition of GSK3β/CKI does not increase β-catenin–mediated transcription. GSK3β/CKI-phosphorylated and -nonphosphorylated APC also localize along adherens junctions, which requires actin and Cell–Cell Adhesion. Significantly, inhibition of Cell–Cell Adhesion results in loss of lateral membrane APC and a concomitant increase in GSK3β/CKI-phosphorylated APC in clusters. These results uncouple different APC functions and show that GSK3β/CKI phosphorylation regulates APC clusters and Cell migration independently of Cell–Cell Adhesion and β-catenin transcriptional activity.
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localized zones of rho and rac activities drive initiation and expansion of epithelial Cell Cell Adhesion
Journal of Cell Biology, 2007Co-Authors: Soichiro Yamada, James W NelsonAbstract:Spatiotemporal coordination of Cell–Cell Adhesion involving lamellipodial interactions, cadherin engagement, and the lateral expansion of the contact is poorly understood. Using high-resolution live-Cell imaging, biosensors, and small molecule inhibitors, we investigate how Rac1 and RhoA regulate actin dynamics during de novo contact formation between pairs of epithelial Cells. Active Rac1, the Arp2/3 complex, and lamellipodia are initially localized to de novo contacts but rapidly diminish as E-cadherin accumulates; further rounds of activation and down-regulation of Rac1 and Arp2/3 occur at the contacting membrane periphery, and this cycle repeats as a restricted membrane zone that moves outward with the expanding contact. The cortical bundle of actin filaments dissolves beneath the expanding contacts, leaving actin bundles at the contact edges. RhoA and actomyosin contractility are activated at the contact edges and are required to drive expansion and completion of Cell–Cell Adhesion. We show that zones of Rac1 and lamellipodia activity and of RhoA and actomyosin contractility are restricted to the periphery of contacting membranes and together drive initiation, expansion, and completion of Cell–Cell Adhesion.
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spatio temporal regulation of rac1 localization and lamellipodia dynamics during epithelial Cell Cell Adhesion
Developmental Cell, 2002Co-Authors: Jason S Ehrlich, Marc D.h. Hansen, James W NelsonAbstract:Cadherin-dependent epithelial Cell-Cell Adhesion is thought to be regulated by Rho family small GTPases and PI 3-kinase, but the mechanisms involved are poorly understood. Using time-lapse microscopy and quantitative image analysis, we show that Cell-Cell contact in MDCK epithelial Cells coincides with a spatio-temporal reorganization of plasma membrane Rac1 and lamellipodia from noncontacting to contacting surfaces. Within contacts, Rac1 and lamellipodia transiently concentrate at newest sites, but decrease at older, stabilized sites. Significantly, Rac1 mutants alter kinetics of Cell-Cell Adhesion and strengthening, but not the eventual generation of Cell-Cell contacts. Products of PI 3-kinase activity also accumulate dynamically at contacts, but are not essential for either initiation or development of Cell-Cell Adhesion. These results define a role for Rac1 in regulating the rates of initiation and strengthening of Cell-Cell Adhesion.
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mechanisms of epithelial Cell Cell Adhesion and Cell compaction revealed by high resolution tracking of e cadherin green fluorescent protein
Journal of Cell Biology, 1998Co-Authors: Cynthia L Adams, Yihtai Chen, Stephen J Smith, James W NelsonAbstract:Cadherin-mediated Adhesion initiates Cell reorganization into tissues, but the mechanisms and dynamics of such Adhesion are poorly understood. Using time-lapse imaging and photobleach recovery analyses of a fully functional E-cadherin/GFP fusion protein, we define three sequential stages in Cell–Cell Adhesion and provide evidence for mechanisms involving E-cadherin and the actin cytoskeleton in transitions between these stages. In the first stage, membrane contacts between two Cells initiate coalescence of a highly mobile, diffuse pool of Cell surface E-cadherin into immobile punctate aggregates along contacting membranes. These E-cadherin aggregates are spatially coincident with membrane attachment sites for actin filaments branching off from circumferential actin cables that circumscribe each Cell. In the second stage, circumferential actin cables near Cell–Cell contact sites separate, and the resulting two ends of the cable swing outwards to the perimeter of the contact. Concomitantly, subsets of E-cadherin puncta are also swept to the margins of the contact where they coalesce into large E-cadherin plaques. This reorganization results in the formation of a circumferential actin cable that circumscribes both Cells, and is embedded into each E-cadherin plaque at the contact margin. At this stage, the two Cells achieve maximum contact, a process referred to as compaction. These changes in E-cadherin and actin distributions are repeated when additional single Cells adhere to large groups of Cells. The third stage of Adhesion occurs as additional Cells are added to groups of >3 Cells; circumferential actin cables linked to E-cadherin plaques on adjacent Cells appear to constrict in a purse-string action, resulting in the further coalescence of individual plaques into the vertices of multiCell contacts. The reorganization of E-cadherin and actin results in the condensation of Cells into colonies. We propose a model to explain how, through strengthening and compaction, E-cadherin and actin cables coordinate to remodel initial Cell–Cell contacts to the final condensation of Cells into colonies.
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mechanisms of epithelial Cell Cell Adhesion and Cell compaction revealed by high resolution tracking of e cadherin green fluorescent protein
Journal of Cell Biology, 1998Co-Authors: Cynthia L Adams, Yihtai Chen, Stephen J Smith, James W NelsonAbstract:Cadherin-mediated Adhesion initiates Cell reorganization into tissues, but the mechanisms and dynamics of such Adhesion are poorly understood. Using time-lapse imaging and photobleach recovery analyses of a fully functional E-cadherin/GFP fusion protein, we define three sequential stages in Cell–Cell Adhesion and provide evidence for mechanisms involving E-cadherin and the actin cytoskeleton in transitions between these stages. In the first stage, membrane contacts between two Cells initiate coalescence of a highly mobile, diffuse pool of Cell surface E-cadherin into immobile punctate aggregates along contacting membranes. These E-cadherin aggregates are spatially coincident with membrane attachment sites for actin filaments branching off from circumferential actin cables that circumscribe each Cell. In the second stage, circumferential actin cables near Cell–Cell contact sites separate, and the resulting two ends of the cable swing outwards to the perimeter of the contact. Concomitantly, subsets of E-cadherin puncta are also swept to the margins of the contact where they coalesce into large E-cadherin plaques. This reorganization results in the formation of a circumferential actin cable that circumscribes both Cells, and is embedded into each E-cadherin plaque at the contact margin. At this stage, the two Cells achieve maximum contact, a process referred to as compaction. These changes in E-cadherin and actin distributions are repeated when additional single Cells adhere to large groups of Cells. The third stage of Adhesion occurs as additional Cells are added to groups of >3 Cells; circumferential actin cables linked to E-cadherin plaques on adjacent Cells appear to constrict in a purse-string action, resulting in the further coalescence of individual plaques into the vertices of multiCell contacts. The reorganization of E-cadherin and actin results in the condensation of Cells into colonies. We propose a model to explain how, through strengthening and compaction, E-cadherin and actin cables coordinate to remodel initial Cell–Cell contacts to the final condensation of Cells into colonies.
Masatoshi Takeichi - One of the best experts on this subject based on the ideXlab platform.
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dynamic behavior of the cadherin based Cell Cell Adhesion system during drosophila gastrulation
Developmental Biology, 1998Co-Authors: Shoichiro Tsukita, Masatoshi TakeichiAbstract:During Drosophila gastrulation, morphogenesis occurs as a series of Cell shape changes and Cell movements which probably involve adhesive interactions between Cells. In the present study, we examined the dynamic aspects of cadherin-based Cell-Cell Adhesion in the morphogenetic events to assess its contribution to morphogenesis. DE- and DN-cadherin show complementary expression patterns in the presumptive ectoderm and mesoderm at the mRNA level. We found that switching of cadherin expression from the DE- to the DN-type in the mesodermal germ layer occurred downstream of the mesoderm-determination genes twist and snail. However, examination of their protein expression patterns showed that considerable amounts of DE-cadherin remained on the surfaces of mesodermal Cells during invagination, while DN-cadherin did not appear on the Cell surfaces at this stage. Further immunocytochemical analysis of the localizations of DE-cadherin and its associated proteins Armadillo (beta-catenin) and Dalpha-catenin revealed dynamic changes in their distributions which were accompanied by changes in Cell morphology in the neuroectoderm and mesoderm. Simultaneously, adherens junctions (AJs), based on the cadherin-catenin system, were shown to change their location, size, and morphology. These dynamic aspects of cadherin-based Cell-Cell Adhesion appeared to be associated with the following: (1) initial establishment of the blastoderm epithelium, (2) acquisition of Cell motility in the neuroectoderm, (3) Cell sheet folding, and (4) epithelial to mesenchymal conversion of the mesoderm. These observations suggest that the behavior of the DE-cadherin-catenin Adhesion system may be regulated in a stepwise manner during gastrulation to perform successive Cell-morphology conversions. Moreover, the processes responsible for loss of epithelial Cell polarity and elimination of preexisting DE-cadherin-based epithelial junctions during early mesodermal morphogenesis are discussed.
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a drosophila homolog of cadherin associated with armadillo and essential for embryonic Cell Cell Adhesion
Developmental Biology, 1994Co-Authors: Hiroki Oda, Tadashi Uemura, Yoshito Harada, Youichi Iwai, Masatoshi TakeichiAbstract:We have identified a Drosophila homolog of vertebrate classic cadherins. A monoclonal antibody to Drosophila α-catenin (Dα-catenin) copurifies a 150-kDa glycoprotein (gp150) along with the α-catenin. To further characterize this protein, we generated monoclonal antibodies to gp150 and isolated its cDNAs using the antibodies. Predicted sequences of the encoded product revealed that it is a transmembrane protein with similarity to vertebrate classic cadherins, and so we designated this molecule DE-cadherin. The extraCellular domain has six cadherin-specific repeats, although the first repeat seems to be cleaved off upon maturation, and the cytoplasmic domain shows significant identity to that of vertebrate classic cadherins. DE-cadherin is distinguishable from its vertebrate counterparts by a large insertion with local sequence similarity to Fat, laminin A chain, Slit, and neurexin I at the proximal region of the extraCellular domain. Despite such differences, DE-cadherin is functionally similar to vertebrate classic cadherins. For example, it is associated with α-catenin and β-catenin (Armadillo), and protected from trypsin digestion only in the presence of Ca2+, as is the case for many of classic cadherins. Transfection of S2 Cells with the D E-cadherin cDNA enhances their Ca2+ -dependent Cell aggregation. Antibodies to this molecule inhibited aggregation of not only the transfectants but also early embryonic Cells, DE-cadherin is concentrated at the apical poles of epithelial Cell-Cell junctions. All these results suggest that DE-cadherin is a homolog of vertebrate classic cadherins and that the vertebrate and invertebrate share common mechanisms for regulation of Cell-Cell Adhesion.
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cadherin mediated Cell Cell Adhesion is perturbed by v src tyrosine phosphorylation in metastatic fibroblasts
Journal of Cell Biology, 1992Co-Authors: N Matsuyoshi, Shoichiro Tsukita, M Hamaguchi, S Taniguchi, Akira Nagafuchi, Masatoshi TakeichiAbstract:Rat 3Y1 Cells acquire metastatic potential when transformed with v-src, and this potential is enhanced by double transformation with v-src and v-fos (Taniguchi, S., T. Kawano, T. Mitsudomi, G. Kimura, and T. Baba. 1986. Jpn. J. Cancer Res. 77:1193-1197). We compared the activity of cadherin Cell Adhesion molecules of normal 3Y1 Cells with that of v-src transformed (SR3Y1) and v-src and v-fos double transformed (fosSR3Y1) 3Y1 Cells. These Cells expressed similar amounts of P-cadherin, and showed similar rates of cadherin-mediated aggregation under suspended conditions. However, the aggregates or colonies of these Cells were morphologically distinct. Normal 3Y1 Cells formed compacted aggregates in which Cells are firmly connected with each other, whereas the transformed Cells were more loosely associated, and could freely migrate out of the colonies. Overexpression of exogenous E-cadherin in these transformed Cells had no significant effect on their adhesive properties. We then found that herbimycin A, a tyrosine kinase inhibitor, induced tighter Cell-Cell associations in the aggregates of the transformed Cells. In contrast, vanadate, a tyrosine phosphatase inhibitor, inhibited the cadherin-mediated aggregation of SR3Y1 and fosSR3Y1 Cells but had little effect on that of normal 3Y1 Cells. These results suggest that v-src-mediated tyrosine phosphorylation perturbs cadherin function directly or indirectly, and the inhibition of tyrosine phosphorylation restores cadherin action to the normal state. We next studied tyrosine phosphorylation on cadherins and the cadherin-associated proteins, catenins. While similar amounts of catenins were expressed in all of these Cells, the 98-kD catenin was strongly tyrosine phosphorylated only in SR3Y1 and fosSR3Y1 Cells. Cadherins were also weakly tyrosine phosphorylated only in the transformed Cells. The tyrosine phosphorylation of these proteins was enhanced by vanadate, and inhibited by herbimycin A. Thus, the tyrosine phosphorylation of the cadherin-catenin system itself might affect its function, causing instable Cell-Cell Adhesion.
Peter L Hordijk - One of the best experts on this subject based on the ideXlab platform.
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proline rich tyrosine kinase 2 pyk2 mediates vascular endothelial cadherin based Cell Cell Adhesion by regulating β catenin tyrosine phosphorylation
Journal of Biological Chemistry, 2005Co-Authors: Jaap D Van Buul, Eloise C Anthony, Mar Fernandezborja, Keith Burridge, Peter L HordijkAbstract:Abstract Vascular endothelial-cadherin (VE-cadherin) controls endothelial Cell-Cell Adhesion and preserves endothelial integrity. In order to maintain endothelial barrier function, VE-cadherin function is tightly regulated through mechanisms that involve protein phosphorylation and cytoskeletal dynamics. Here, we show that loss of VE-cadherin function results in interCellular gap formation and a drop in electrical resistance of monolayers of primary human endothelial Cells. Detailed analysis revealed that loss of endothelial Cell-Cell Adhesion, induced by VE-cadherin-blocking antibodies, is preceded by and dependent on a rapid activation of Rac1 and increased production of reactive oxygen species. Moreover, VE-cadherin-associated β-catenin is tyrosine-phosphorylated upon loss of Cell-Cell contact. Finally, the redox-sensitive proline-rich tyrosine kinase 2 (Pyk2) is activated and recruited to Cell-Cell junctions following the loss of VE-cadherin homotypic Adhesion. Conversely, the inhibition of Pyk2 activity in endothelial Cells by the expression of CRNK (CADTK/CAKβ-related non-kinase), an N-terminal deletion mutant that acts in a dominant negative fashion, not only abolishes the increase in β-catenin tyrosine phosphorylation but also prevents the loss of endothelial Cell-Cell contact. These results implicate Pyk2 in the reduced Cell-Cell Adhesion induced by the Rac-mediated production of ROS through the tyrosine phosphorylation of β-catenin. This signaling is initiated upon loss of VE-cadherin function and is important for our insight in the modulation of endothelial integrity.
Shoichiro Tsukita - One of the best experts on this subject based on the ideXlab platform.
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dynamic behavior of the cadherin based Cell Cell Adhesion system during drosophila gastrulation
Developmental Biology, 1998Co-Authors: Shoichiro Tsukita, Masatoshi TakeichiAbstract:During Drosophila gastrulation, morphogenesis occurs as a series of Cell shape changes and Cell movements which probably involve adhesive interactions between Cells. In the present study, we examined the dynamic aspects of cadherin-based Cell-Cell Adhesion in the morphogenetic events to assess its contribution to morphogenesis. DE- and DN-cadherin show complementary expression patterns in the presumptive ectoderm and mesoderm at the mRNA level. We found that switching of cadherin expression from the DE- to the DN-type in the mesodermal germ layer occurred downstream of the mesoderm-determination genes twist and snail. However, examination of their protein expression patterns showed that considerable amounts of DE-cadherin remained on the surfaces of mesodermal Cells during invagination, while DN-cadherin did not appear on the Cell surfaces at this stage. Further immunocytochemical analysis of the localizations of DE-cadherin and its associated proteins Armadillo (beta-catenin) and Dalpha-catenin revealed dynamic changes in their distributions which were accompanied by changes in Cell morphology in the neuroectoderm and mesoderm. Simultaneously, adherens junctions (AJs), based on the cadherin-catenin system, were shown to change their location, size, and morphology. These dynamic aspects of cadherin-based Cell-Cell Adhesion appeared to be associated with the following: (1) initial establishment of the blastoderm epithelium, (2) acquisition of Cell motility in the neuroectoderm, (3) Cell sheet folding, and (4) epithelial to mesenchymal conversion of the mesoderm. These observations suggest that the behavior of the DE-cadherin-catenin Adhesion system may be regulated in a stepwise manner during gastrulation to perform successive Cell-morphology conversions. Moreover, the processes responsible for loss of epithelial Cell polarity and elimination of preexisting DE-cadherin-based epithelial junctions during early mesodermal morphogenesis are discussed.
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translocation of activated rho from the cytoplasm to membrane ruffling area Cell Cell Adhesion sites and cleavage furrows
Oncogene, 1995Co-Authors: Kenji Takaishi, Takuya Sasaki, Shoichiro Tsukita, Takeshi Kameyama, Yoshimi TakaiAbstract:Rho small GTP-binding protein regulates various Cell functions, such as formation of stress fibers and focal Adhesions, Cell motility, membrane ruffling, cytokinesis and smooth muscle contraction in mammalian Cells and bud formation in the yeast Saccharomyces cerevisiae. As to the functioning sites of Rho in Saccharomyces cerevisiae, we have recently shown that RHO1 protein, a homologue of mammalian RhoA, is concentrated to the growth region of the Cells where cortical actin patches are clustered. However, in mammalian Cells, the functioning sites of Rho have not yet been studied. In the present study, MDCK Cell lines stably expressing myc-tagged RhoA (myc-RhoA) were prepared and localization of myc-RhoA was first immunohistochemically examined using an anti-myc antibody. In the resting Cells, almost all of myc-RhoA was observed in the cytosol. When the Cells were stimulated with phorbol ester or hepatocyte growth factor, membrane rufflings were induced and myc-RhoA was translocated to the membrane ruffling area. Moreover, myc-RhoA was translocated from the cytosol to the Cell-Cell Adhesion sites when the Cells were transferred from a low to normal Ca2+ medium. RhoA was also concentrated to the cleavage furrows during cytokinesis in Swiss 3T3 Cells. Translocation of myc-RhoA to the membrane ruffling area was inhibited by prior microinjection into the Cells of Rho GDI, a negative regulator of Rho which inhibits activation of Rho, or of C3, an exoenzyme of Clostridium botulinum which ADP-ribosylates Rho and inhibits its functions, indicating that both activation and functioning of Rho are essential for the translocation of Rho. The ERM (Ezrin, Radixin, Moesin) family members were colocalized with RhoA at all of these sites. However, RhoA was not apparently observed at the focal Adhesion plaque where vinculin was localized. These results suggest that at least one of the functioning sites of Rho is the ERM family-controlled actin filament/plasma membrane association sites.
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cadherin mediated Cell Cell Adhesion is perturbed by v src tyrosine phosphorylation in metastatic fibroblasts
Journal of Cell Biology, 1992Co-Authors: N Matsuyoshi, Shoichiro Tsukita, M Hamaguchi, S Taniguchi, Akira Nagafuchi, Masatoshi TakeichiAbstract:Rat 3Y1 Cells acquire metastatic potential when transformed with v-src, and this potential is enhanced by double transformation with v-src and v-fos (Taniguchi, S., T. Kawano, T. Mitsudomi, G. Kimura, and T. Baba. 1986. Jpn. J. Cancer Res. 77:1193-1197). We compared the activity of cadherin Cell Adhesion molecules of normal 3Y1 Cells with that of v-src transformed (SR3Y1) and v-src and v-fos double transformed (fosSR3Y1) 3Y1 Cells. These Cells expressed similar amounts of P-cadherin, and showed similar rates of cadherin-mediated aggregation under suspended conditions. However, the aggregates or colonies of these Cells were morphologically distinct. Normal 3Y1 Cells formed compacted aggregates in which Cells are firmly connected with each other, whereas the transformed Cells were more loosely associated, and could freely migrate out of the colonies. Overexpression of exogenous E-cadherin in these transformed Cells had no significant effect on their adhesive properties. We then found that herbimycin A, a tyrosine kinase inhibitor, induced tighter Cell-Cell associations in the aggregates of the transformed Cells. In contrast, vanadate, a tyrosine phosphatase inhibitor, inhibited the cadherin-mediated aggregation of SR3Y1 and fosSR3Y1 Cells but had little effect on that of normal 3Y1 Cells. These results suggest that v-src-mediated tyrosine phosphorylation perturbs cadherin function directly or indirectly, and the inhibition of tyrosine phosphorylation restores cadherin action to the normal state. We next studied tyrosine phosphorylation on cadherins and the cadherin-associated proteins, catenins. While similar amounts of catenins were expressed in all of these Cells, the 98-kD catenin was strongly tyrosine phosphorylated only in SR3Y1 and fosSR3Y1 Cells. Cadherins were also weakly tyrosine phosphorylated only in the transformed Cells. The tyrosine phosphorylation of these proteins was enhanced by vanadate, and inhibited by herbimycin A. Thus, the tyrosine phosphorylation of the cadherin-catenin system itself might affect its function, causing instable Cell-Cell Adhesion.