scholarly journals Regulation of Cell-Cell Adhesion by Abi/Diaphanous Complexes

2009 ◽  
Vol 29 (7) ◽  
pp. 1735-1748 ◽  
Author(s):  
Jae Ryun Ryu ◽  
Asier Echarri ◽  
Ran Li ◽  
Ann Marie Pendergast
Keyword(s):  
Cell Adhesion ◽  
Epithelial Cells ◽  
Driving Force ◽  
Actin Polymerization ◽  
Binding Protein ◽  
Cell Junctions ◽  
Actin Dynamics ◽  
Binding Partner ◽  
Terminal Fragment ◽  
Cell Cell

ABSTRACT Actin polymerization provides the driving force for the formation of cell-cell junctions and is mediated by two types of actin nucleators, Arp2/3 and formins. Proteins required for coordinately linking cadherin-mediated adhesion to Arp2/3-dependent versus formin-dependent nucleation have yet to be defined. Here we show a role for Abi, the Abi-binding partner Nap1, and the Nap1-binding protein Sra1 in the regulation of cadherin-dependent adhesion. We found that Abi, which is known to interact with Wave, leading to activation of the Arp2/3 complex, is also capable of interacting with the Diaphanous (Dia)-related formins in the absence of Wave. Knockdown of Abi, Nap1, Sra1, or Dia markedly inhibited cell-cell junctions, whereas knockdown of Wave or Arp2/3 produced mild and transient phenotypes. Dia and Abi colocalized with β-catenin at cell-cell junctions. Further, Dia and Wave bound to overlapping sites on Abi1, and Wave competed with Dia for Abi1 binding. Notably, an active Dia1 C-terminal fragment that localizes to cell-cell junctions rescued the abnormal junctions induced by depletion of Abi or Nap1 in epithelial cells. These findings uncover a novel link between cadherin-mediated adhesion and the regulation of actin dynamics through the requirement for an Abi/Dia complex for the formation and stability of cell-cell junctions.

scholarly journals Junctional actin assembly is mediated by Formin-like 2 downstream of Rac1

2015 ◽  
Vol 209 (3) ◽  
pp. 367-376 ◽  
Author(s):  
Katharina Grikscheit ◽  
Tanja Frank ◽  
Ying Wang ◽  
Robert Grosse
Keyword(s):  
Cell Adhesion ◽  
Epithelial Cells ◽  
Actin Polymerization ◽  
De Novo ◽  
Early Stage ◽  
Adhesion Formation ◽  
Actin Dynamics ◽  
Cell Contact ◽  
Actin Assembly ◽  
Cell Cell

Epithelial integrity is vitally important, and its deregulation causes early stage cancer. De novo formation of an adherens junction (AJ) between single epithelial cells requires coordinated, spatial actin dynamics, but the mechanisms steering nascent actin polymerization for cell–cell adhesion initiation are not well understood. Here we investigated real-time actin assembly during daughter cell–cell adhesion formation in human breast epithelial cells in 3D environments. We identify formin-like 2 (FMNL2) as being specifically required for actin assembly and turnover at newly formed cell–cell contacts as well as for human epithelial lumen formation. FMNL2 associates with components of the AJ complex involving Rac1 activity and the FMNL2 C terminus. Optogenetic control of Rac1 in living cells rapidly drove FMNL2 to epithelial cell–cell contact zones. Furthermore, Rac1-induced actin assembly and subsequent AJ formation critically depends on FMNL2. These data uncover FMNL2 as a driver for human epithelial AJ formation downstream of Rac1.

scholarly journals Actin protrusions push on E-cadherin to maintain epithelial cell-cell adhesion

2019 ◽  
Author(s):  
John Xiao He Li ◽  
Vivian W. Tang ◽  
William M. Brieher
Keyword(s):  
Cell Adhesion ◽  
Actin Polymerization ◽  
Mdck Cells ◽  
Myosin Ii ◽  
Cell Junctions ◽  
Apical Junctions ◽  
Actin Protrusions ◽  
Adhesive Contacts ◽  
E Cadherin ◽  
Cell Cell

AbstractCadherin mediated cell-cell adhesion is actin dependent, but the precise role of actin in maintaining cell-cell adhesion is not fully understood. Actin polymerization-dependent protrusive activity is required to push distally separated cells close enough together to initiate contact. Whether protrusive activity is required to maintain adhesion in confluent sheets of epithelial cells is not known. By electron microscopy as well as live cell imaging, we have identified a population of protruding actin microspikes that operate continuously near apical junctions of polarized MDCK cells. Live imaging shows that microspikes containing E-cadherin extend into gaps between E-cadherin clusters on neighboring cells while reformation of cadherin clusters across the cell-cell boundary triggers microspike withdrawal. We identify Arp2/3, EVL, and CRMP-1 as three actin assembly factors necessary for microspike formation. Depleting these factors from cells using RNAi results in myosin II-dependent unzipping of cadherin adhesive bonds. Therefore, actin polymerization-dependent protrusive activity operates continuously at cadherin cell-cell junctions to keep them shut and to prevent myosin II-dependent contractility from tearing cadherin adhesive contacts apart.

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.

scholarly journals Comprehensive analysis of formin localization in Xenopus epithelial cells

2019 ◽  
Vol 30 (1) ◽  
pp. 82-95 ◽  
Author(s):  
Tomohito Higashi ◽  
Rachel E. Stephenson ◽  
Ann L. Miller
Keyword(s):  
Epithelial Cells ◽  
Comprehensive Analysis ◽  
Cell Junctions ◽  
Actin Dynamics ◽  
Cell Junction ◽  
Contractile Ring ◽  
Dimerization Domain ◽  
Cellular Processes ◽  
And Function ◽  
Cell Cell

Reorganization of the actin cytoskeleton is crucial for cellular processes, including cytokinesis and cell–cell junction remodeling. Formins are conserved processive actin-polymerizing machines that regulate actin dynamics by nucleating, elongating, and bundling linear actin filaments. Because the formin family is large, with at least 15 members in vertebrates, there have not been any comprehensive studies examining formin localization and function within a common cell type. Here, we characterized the localization of all 15 formins in epithelial cells of Xenopus laevis gastrula-stage embryos. Dia1 and Dia2 localized to tight junctions, while Fhod1 and Fhod3 localized to adherens junctions. Only Dia3 strongly localized at the cytokinetic contractile ring. The Diaphanous inhibitory domain–dimerization domain (DID-DD) region of Dia1 was sufficient for Dia1 localization, and overexpression of a Dia1 DID-DD fragment competitively removed Dia1 and Dia2 from cell–cell junctions. In Dia1 DID-DD–overexpressing cells, Dia1 and Dia2 were mislocalized to the contractile ring, and cells exhibited increased cytokinesis failure. This work provides a comprehensive analysis of the localization of all 15 vertebrate formins in epithelial cells and suggests that misregulated formin localization results in epithelial cytokinesis failure.

scholarly journals Directed Actin Polymerization Is the Driving Force for Epithelial Cell–Cell Adhesion

Cell ◽  
2000 ◽  
Vol 100 (2) ◽  
pp. 209-219 ◽  
Author(s):  
Valeri Vasioukhin ◽  
Christoph Bauer ◽  
Mei Yin ◽  
Elaine Fuchs
Keyword(s):  
Cell Adhesion ◽  
Epithelial Cell ◽  
Driving Force ◽  
Actin Polymerization ◽  
Cell Cell

scholarly journals Actin protrusions push at apical junctions to maintain E-cadherin adhesion

2019 ◽  
Vol 117 (1) ◽  
pp. 432-438 ◽  
Author(s):  
John Xiao He Li ◽  
Vivian W. Tang ◽  
William M. Brieher
Keyword(s):  
Cell Adhesion ◽  
Actin Polymerization ◽  
Mdck Cells ◽  
Myosin Ii ◽  
Cell Junctions ◽  
Apical Junctions ◽  
Actin Protrusions ◽  
Adhesive Contacts ◽  
E Cadherin ◽  
Cell Cell

Cadherin-mediated cell–cell adhesion is actin-dependent, but the precise role of actin in maintaining cell–cell adhesion is not fully understood. Actin polymerization-dependent protrusive activity is required to push distally separated cells close enough to initiate contact. Whether protrusive activity is required to maintain adhesion in confluent sheets of epithelial cells is not known. By electron microscopy as well as live cell imaging, we have identified a population of protruding actin microspikes that operate continuously near apical junctions of polarized Madin-Darby canine kidney (MDCK) cells. Live imaging shows that microspikes containing E-cadherin extend into gaps between E-cadherin clusters on neighboring cells, while reformation of cadherin clusters across the cell–cell boundary correlates with microspike withdrawal. We identify Arp2/3, EVL, and CRMP-1 as 3 actin assembly factors necessary for microspike formation. Depleting these factors from cells using RNA interference (RNAi) results in myosin II-dependent unzipping of cadherin adhesive bonds. Therefore, actin polymerization-dependent protrusive activity operates continuously at cadherin cell–cell junctions to keep them shut and to prevent myosin II-dependent contractility from tearing cadherin adhesive contacts apart.

Microtubule dynamics and Rac-1 signaling independently regulate barrier function in lung epithelial cells

2007 ◽  
Vol 293 (5) ◽  
pp. L1321-L1331 ◽  
Author(s):  
Magdalena J. Lorenowicz ◽  
Mar Fernandez-Borja ◽  
Anne-Marieke D. van Stalborch ◽  
Marian A. J. A. van Sterkenburg ◽  
Pieter S. Hiemstra ◽  
...  
Keyword(s):  
Cell Adhesion ◽  
Epithelial Cells ◽  
Barrier Function ◽  
Lung Epithelial Cells ◽  
Cell Junctions ◽  
Epithelial Barrier ◽  
Cell Contact ◽  
Epithelial Barrier Function ◽  
Lung Epithelial ◽  
Cell Cell

Cadherin-mediated cell-cell adhesion controls the morphology and function of epithelial cells and is a critical component of the pathology of chronic inflammatory disorders. Dynamic interactions between cadherins and the actin cytoskeleton are required for stable cell-cell contact. Besides actin, microtubules also target intercellular, cadherin-based junctions and contribute to their formation and stability. Here, we studied the role of microtubules in conjunction with Rho-like GTPases in the regulation of lung epithelial barrier function using real-time monitoring of transepithelial electrical resistance. Unexpectedly, we found that disruption of microtubules promotes epithelial cell-cell adhesion. This increase in epithelial barrier function is accompanied by the accumulation of β-catenin at cell-cell junctions, as detected by immunofluorescence. Moreover, we found that the increase in cell-cell contact, induced by microtubule depolymerization, requires signaling through a RhoA/Rho kinase pathway. The Rac-1 GTPase counteracts this pathway, because inhibition of Rac-1 signaling rapidly promotes epithelial barrier function, in a microtubule- and RhoA-independent fashion. Together, our data suggest that microtubule-RhoA-mediated signaling and Rac-1 control lung epithelial integrity through counteracting independent pathways.

scholarly journals αE-catenin regulates actin dynamics independently of cadherin-mediated cell–cell adhesion

2010 ◽  
Vol 189 (2) ◽  
pp. 339-352 ◽  
Author(s):  
Jacqueline M. Benjamin ◽  
Adam V. Kwiatkowski ◽  
Changsong Yang ◽  
Farida Korobova ◽  
Sabine Pokutta ◽  
...  
Keyword(s):  
Cell Adhesion ◽  
Actin Polymerization ◽  
Membrane Dynamics ◽  
Actin Dynamics ◽  
Filamentous Actin ◽  
Vitro Binding ◽  
Adhesion Complex ◽  
E Cadherin ◽  
Cell Cell

αE-catenin binds the cell–cell adhesion complex of E-cadherin and β-catenin (β-cat) and regulates filamentous actin (F-actin) dynamics. In vitro, binding of αE-catenin to the E-cadherin–β-cat complex lowers αE-catenin affinity for F-actin, and αE-catenin alone can bind F-actin and inhibit Arp2/3 complex–mediated actin polymerization. In cells, to test whether αE-catenin regulates actin dynamics independently of the cadherin complex, the cytosolic αE-catenin pool was sequestered to mitochondria without affecting overall levels of αE-catenin or the cadherin–catenin complex. Sequestering cytosolic αE-catenin to mitochondria alters lamellipodia architecture and increases membrane dynamics and cell migration without affecting cell–cell adhesion. In contrast, sequestration of cytosolic αE-catenin to the plasma membrane reduces membrane dynamics. These results demonstrate that the cytosolic pool of αE-catenin regulates actin dynamics independently of cell–cell adhesion.

Expression and role of E- and P-cadherin adhesion molecules in embryonic histogenesis. I. Lung epithelial morphogenesis

Development ◽  
1989 ◽  
Vol 105 (2) ◽  
pp. 263-270 ◽  
Author(s):  
Y. Hirai ◽  
A. Nose ◽  
S. Kobayashi ◽  
M. Takeichi
Keyword(s):  
Monoclonal Antibody ◽  
Cell Adhesion ◽  
Epithelial Cells ◽  
Adhesion Molecules ◽  
Lung Epithelial Cells ◽  
Early Developmental Stage ◽  
Subtle Effect ◽  
Lung Epithelial ◽  
Cell Cell

The role of Ca2+-dependent cell-cell adhesion molecules, E- and P-cadherins, in the histogenesis of mouse embryonic lung was studied. All epithelial cells of the lung express both E- and P-cadherin at the early developmental stage. P-cadherin, however, gradually disappears during development, initially from the main bronchi and eventually from all epithelial cells. When a monoclonal antibody to E-cadherin (ECCD-1) was added to monolayer cultures of lung epithelial cells, it induced a partial disruption of their cell-cell adhesion, while a monoclonal antibody to P-cadherin (PCD-1) showed a subtle effect. A mixture of the two antibodies, however, displayed a synergistic effect. We then tested the effect of the antibodies on the morphogenesis of lung primordia using an organ culture system. In control media, the explants formed typical bronchial trees. In the presence of ECCD-1, the explants grew up at the same rate as in the control, but their morphogenesis was affected. The control explants formed round epithelial lobules with an open luminal space at the tips of the bronchial trees, whereas the lobules of explants incubated with ECCD-1 tended to be flat and devoid of the luminal space. PCD-1 showed a similar but very small effect. A mixture of the two antibodies, however, showed a stronger effect: the branching of epithelia was partially suppressed and the arrangement of epithelial cells was distorted in many places. These results suggest that E- and P-cadherin have a synergistic role in the organization of epithelial cells in lung morphogenesis.

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