Role of IQGAP1, a Target of the Small GTPases Cdc42 and Rac1, in Regulation of E-Cadherin- Mediated Cell-Cell Adhesion

Rac1, a member of the Ρ family small GTPases, regulates E-cadherin-mediated cell-cell adhesion. However, it remains to be clarified how the localization and activation of Rac1 are regulated at sites of cell-cell contact. Here, using enhanced green fluorescence protein (EGFP)-tagged Rac1, we demonstrate that EGFP-Rac1 is colocalized with E-cadherin at sites of cell-cell contact and translocates to the cytosol during disruption of E-cadherin-mediated cell-cell adhesion by Ca(2+) chelation. Re-establishment of cell-cell adhesion by restoration of Ca(2)(+) caused EGFP-Rac1 to become relocalized, together with E-cadherin, at sites of cell-cell contact. Engagement of E-cadherin to the apical membrane by anti-E-cadherin antibody (ECCD-2) recruited EGFP-Rac1. We also investigated whether E-cadherin-mediated cell-cell adhesion induced Rac1 activation by measuring the amounts of GTP-bound Rac1 based on its specific binding to the Cdc42/Rac1 interactive binding region of p21-activated kinase. The formation of E-cadherin-mediated cell-cell adhesion induced Rac1 activation. This activation was inhibited by treatment of cells with a neutralizing antibody (DECMA-1) against E-cadherin, or with wortmannin, an inhibitor of phosphatidylinositol 3-kinase (PI 3-kinase). IQGAP1, an effector of Rac1, and EGFP-Rac1 behaved in a similar manner during the formation of E-cadherin-mediated cell-cell adhesion. Rac1 activation was also confirmed by measuring the amounts of coimmunoprecipitated Rac1 with IQGAP1 during the establishment of cell-cell adhesion. Taken together, these results suggest that Rac1 is recruited at sites of E-cadherin-mediated cell-cell adhesion and then activated, possibly through PI 3-kinase. http://www/biologists.com/JCS/movies/jcs2094.html

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CD151 regulates epithelial cell–cell adhesion through PKC- and Cdc42-dependent actin cytoskeletal reorganization

The Journal of Cell Biology ◽

10.1083/jcb.200301075 ◽

2003 ◽

Vol 163 (1) ◽

pp. 165-176 ◽

Cited By ~ 90

Author(s):

Masaki Shigeta ◽

Noriko Sanzen ◽

Masayuki Ozawa ◽

Jianguo Gu ◽

Hitoshi Hasegawa ◽

...

Keyword(s):

Cell Adhesion ◽

Epithelial Cell ◽

Cytoskeletal Reorganization ◽

Cortical Actin ◽

A431 Cells ◽

Kinase C ◽

Integrin Α3β1 ◽

E Cadherin ◽

Cell Cell

CD151, a member of the tetraspanin family proteins, tightly associates with integrin α3β1 and localizes at basolateral surfaces of epithelial cells. We found that overexpression of CD151 in A431 cells accelerated intercellular adhesion, whereas treatment of cells with anti-CD151 mAb perturbed the integrity of cortical actin filaments and cell polarity. E-Cadherin puncta formation, indicative of filopodia-based adhesion zipper formation, as well as E-cadherin anchorage to detergent-insoluble cytoskeletal matrix, was enhanced in CD151-overexpressing cells. Levels of GTP-bound Cdc42 and Rac were also elevated in CD151-overexpressing cells, suggesting the role of CD151 in E-cadherin–mediated cell–cell adhesion as a modulator of actin cytoskeletal reorganization. Consistent with this possibility, engagement of CD151 by the substrate-adsorbed anti-CD151 mAb induced prominent Cdc42-dependent filopodial extension, which along with E-cadherin puncta formation, was strongly inhibited by calphostin C, a protein kinase C (PKC) inhibitor. Together, these results indicate that CD151 is involved in epithelial cell–cell adhesion as a modulator of PKC- and Cdc42-dependent actin cytoskeletal reorganization.

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Mouse proximal tubular cell-cell adhesion inhibits apoptosis by a cadherin-dependent mechanism

AJP Renal Physiology ◽

10.1152/ajprenal.2000.278.5.f758 ◽

2000 ◽

Vol 278 (5) ◽

pp. F758-F768 ◽

Cited By ~ 54

Author(s):

Eoin Bergin ◽

Jerrold S. Levine ◽

Jason S. Koh ◽

Wilfred Lieberthal

Keyword(s):

Cell Adhesion ◽

Primary Cultures ◽

Cell Aggregation ◽

Cell Matrix ◽

Proximal Tubular ◽

Cell Matrix Interactions ◽

Suspended Cells ◽

E Cadherin ◽

Cell Cell

Adhesion of epithelial cells to matrix is known to inhibit apoptosis. However, the role of cell-cell adhesion in mediating cell survival remains uncertain. Primary cultures of mouse proximal tubular (MPT) cells were used to examine the role of cell-cell adhesion in promoting survival. When MPT cells were deprived of both cell-matrix and cell-cell adhesion, they died by apoptosis. However, when incubated in agarose-coated culture dishes (to prevent cell-matrix adhesion) and at high cell density (to allow cell-cell interactions), MPT cells adhered to one another and remained viable. Expression of E-cadherin among suspended, aggregating cells increased with time. A His-Ala-Val (HAV)-containing peptide that inhibits homophilic E-cadherin binding prevented cell-cell aggregation and promoted apoptosis of MPT cells in suspension. By contrast, inhibition of potential β1-integrin-mediated interactions between cells in suspension did not prevent either aggregation or survival of suspended cells. Aggregation of cells in suspension activated phosphatidylinositol 3-kinase (PI3K), an event that was markedly reduced by the presence of the HAV peptide. LY-294002, an inhibitor of PI3K, also inhibited survival of suspended cells. In summary, we provide novel evidence that MPT cells, when deprived of normal cell-matrix interactions, can adhere to one another in a cadherin-dependent fashion and remain viable. Survival of aggregated cells depends on activation of PI3K.

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Role of Cadherins in Cancer—A Review

International Journal of Molecular Sciences ◽

10.3390/ijms21207624 ◽

2020 ◽

Vol 21 (20) ◽

pp. 7624

Author(s):

Ilona Kaszak ◽

Olga Witkowska-Piłaszewicz ◽

Zuzanna Niewiadomska ◽

Bożena Dworecka-Kaszak ◽

Felix Ngosa Toka ◽

...

Keyword(s):

Cell Adhesion ◽

Tumor Progression ◽

Signaling Pathways ◽

Rho Gtpases ◽

Epithelial Mesenchymal Transition ◽

Clinical Importance ◽

Mesenchymal Transition ◽

E Cadherin ◽

Cell Cell

Cadherins play an important role in tissue homeostasis, as they are responsible for cell-cell adhesion during embryogenesis, tissue morphogenesis, differentiation and carcinogenesis. Cadherins are inseparably connected with catenins, forming cadherin-catenin complexes, which are crucial for cell-to-cell adherence. Any dysfunction or destabilization of cadherin-catenin complex may result in tumor progression. Epithelial mesenchymal transition (EMT) is a mechanism in which epithelial cadherin (E-cadherin) expression is lost during tumor progression. However, during tumorigenesis, many processes take place, and downregulation of E-cadherin, nuclear β-catenin and p120 catenin (p120) signaling are among the most critical. Additional signaling pathways, such as Receptor tyrosine kinase (RTK), Rho GTPases, phosphoinositide 3-kinase (PI3K) and Hippo affect cadherin cell-cell adhesion and also contribute to tumor progression and metastasis. Many signaling pathways may be activated during tumorigenesis; thus, cadherin-targeting drugs seem to limit the progression of malignant tumor. This review discusses the role of cadherins in selected signaling mechanisms involved in tumor growth. The clinical importance of cadherin will be discussed in cases of human and animal cancers.

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A Novel Role of Nectins in Inhibition of the E-Cadherin–induced Activation of Rac and Formation of Cell-Cell Adherens Junctions

Molecular Biology of the Cell ◽

10.1091/mbc.e03-05-0321 ◽

2004 ◽

Vol 15 (3) ◽

pp. 1077-1088 ◽

Cited By ~ 35

Author(s):

Takashi Hoshino ◽

Kazuya Shimizu ◽

Tomoyuki Honda ◽

Tomomi Kawakatsu ◽

Taihei Fukuyama ◽

...

Keyword(s):

Cell Adhesion ◽

G Protein ◽

Adherens Junctions ◽

Resonance Energy Transfer ◽

Resonance Energy ◽

Inhibitory Effect ◽

Small G Protein ◽

E Cadherin ◽

Cell Cell

Nectins are Ca2+-independent immunoglobulin (Ig)-like cell-cell adhesion molecules. The trans-interactions of nectins recruit cadherins to the nectin-based cell-cell adhesion, resulting in formation of cell-cell adherens junctions (AJs) in epithelial cells and fibroblasts. The trans-interaction of E-cadherin induces activation of Rac small G protein, whereas the trans-interactions of nectins induce activation of not only Rac but also Cdc42 small G protein. We showed by the fluorescent resonance energy transfer (FRET) imaging that the trans-interaction of E-cadherin induced dynamic activation and inactivation of Rac, which led to dynamic formation and retraction of lamellipodia. Moreover, we found here that the nectins, which did not trans-interact with other nectins (non–trans-interacting nectins), inhibited the E-cadherin–induced activation of Rac and reduced the velocity of the formation of the E-cadherin-based cell-cell AJs. The inhibitory effect of non–trans-interacting nectins was suppressed by the activation of Cdc42 induced by the trans-interactions of nectins. These results indicate a novel role of nectins in regulation of the E-cadherin–induced activation of Rac and formation of cell-cell AJs.

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p120 catenin associates with kinesin and facilitates the transport of cadherin–catenin complexes to intercellular junctions

The Journal of Cell Biology ◽

10.1083/jcb.200305137 ◽

2003 ◽

Vol 163 (3) ◽

pp. 547-557 ◽

Cited By ~ 172

Author(s):

Xinyu Chen ◽

Shin-ichiro Kojima ◽

Gary G. Borisy ◽

Kathleen J. Green

Keyword(s):

Cell Adhesion ◽

Cell Surface ◽

Deletion Mutant ◽

Intercellular Junctions ◽

Time Lapse ◽

Small Gtpases ◽

P120 Catenin ◽

Time Lapse Imaging ◽

Cell Cell

p120 catenin (p120) is a component of adherens junctions and has been implicated in regulating cadherin-based cell adhesion as well as the activity of Rho small GTPases, but its exact roles in cell–cell adhesion are unclear. Using time-lapse imaging, we show that p120-GFP associates with vesicles and exhibits unidirectional movements along microtubules. Furthermore, p120 forms a complex with kinesin heavy chain through the p120 NH2-terminal head domain. Overexpression of p120, but not an NH2-terminal deletion mutant deficient in kinesin binding, recruits endogenous kinesin to N-cadherin. Disruption of the interaction between N-cadherin and p120, or the interaction between p120 and kinesin, leads to a delayed accumulation of N-cadherin at cell–cell contacts during calcium-initiated junction reassembly. Our analyses identify a novel role of p120 in promoting cell surface trafficking of cadherins via association and recruitment of kinesin.

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