scholarly journals Cell–Cell Adhesion and Myosin Activity Regulate Cortical Actin Assembly in Mammary Gland Epithelium on Concaved Surface

Cells ◽  
2019 ◽  
Vol 8 (8) ◽  
pp. 813
Author(s):  
Wei-Hung Jung ◽  
Khalid Elawad ◽  
Sung Hoon Kang ◽  
Yun Chen

It has been demonstrated that geometry can affect cell behaviors. Though curvature-sensitive proteins at the nanoscale are studied, it is unclear how cells sense curvature at the cellular and multicellular levels. To characterize and determine the mechanisms of curvature-dependent cell behaviors, we grow cells on open channels of the 60-µm radius. We found that cortical F-actin is 1.2-fold more enriched in epithelial cells grown on the curved surface compared to the flat control. We observed that myosin activity is required to promote cortical F-actin formation. Furthermore, cell–cell contact was shown to be indispensable for curvature-dependent cortical actin assembly. Our results indicate that the actomyosin network coupled with adherens junctions is involved in curvature-sensing at the multi-cellular level.

2019 ◽  
Vol 116 (3) ◽  
pp. 375a
Author(s):  
Wei-Hung Jung ◽  
Khalid Elawad ◽  
Sung Hoon Kang ◽  
Yun Chen

2014 ◽  
Vol 207 (5) ◽  
pp. 577-587 ◽  
Author(s):  
Christopher P. Toret ◽  
Caitlin Collins ◽  
W. James Nelson

Cell–cell contact formation is a dynamic process requiring the coordination of cadherin-based cell–cell adhesion and integrin-based cell migration. A genome-wide RNA interference screen for proteins required specifically for cadherin-dependent cell–cell adhesion identified an Elmo–Dock complex. This was unexpected as Elmo–Dock complexes act downstream of integrin signaling as Rac guanine-nucleotide exchange factors. In this paper, we show that Elmo2 recruits Dock1 to initial cell–cell contacts in Madin–Darby canine kidney cells. At cell–cell contacts, both Elmo2 and Dock1 are essential for the rapid recruitment and spreading of E-cadherin, actin reorganization, localized Rac and Rho GTPase activities, and the development of strong cell–cell adhesion. Upon completion of cell–cell adhesion, Elmo2 and Dock1 no longer localize to cell–cell contacts and are not required subsequently for the maintenance of cell–cell adhesion. These studies show that Elmo–Dock complexes are involved in both integrin- and cadherin-based adhesions, which may help to coordinate the transition of cells from migration to strong cell–cell adhesion.


2015 ◽  
Vol 209 (3) ◽  
pp. 367-376 ◽  
Author(s):  
Katharina Grikscheit ◽  
Tanja Frank ◽  
Ying Wang ◽  
Robert Grosse

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.


2004 ◽  
Vol 15 (3) ◽  
pp. 1172-1184 ◽  
Author(s):  
Takahiko Hara ◽  
Hiroshi Ishida ◽  
Razi Raziuddin ◽  
Stephan Dorkhom ◽  
Keiju Kamijo ◽  
...  

Dynamic rearrangements of cell-cell adhesion underlie a diverse range of physiological processes, but their precise molecular mechanisms are still obscure. Thus, identification of novel players that are involved in cell-cell adhesion would be important. We isolated a human kelch-related protein, Kelch-like ECT2 interacting protein (KLEIP), which contains the broad-complex, tramtrack, bric-a-brac (BTB)/poxvirus, zinc finger (POZ) motif and six-tandem kelch repeats. KLEIP interacted with F-actin and was concentrated at cell-cell contact sites of Madin-Darby canine kidney cells, where it colocalized with F-actin. Interestingly, this localization took place transiently during the induction of cell-cell contact and was not seen at mature junctions. KLEIP recruitment and actin assembly were induced around E-cadherin–coated beads placed on cell surfaces. The actin depolymerizing agent cytochalasin B inhibited this KLEIP recruitment around E-cadherin–coated beads. Moreover, constitutively active Rac1 enhanced the recruitment of KLEIP as well as F-actin to the adhesion sites. These observations strongly suggest that KLEIP is localized on actin filaments at the contact sites. We also found that N-terminal half of KLEIP, which lacks the actin-binding site and contains the sufficient sequence for the localization at the cell-cell contact sites, inhibited constitutively active Rac1-induced actin assembly at the contact sites. We propose that KLEIP is involved in Rac1-induced actin organization during cell-cell contact in Madin-Darby canine kidney cells.


1990 ◽  
Vol 110 (5) ◽  
pp. 1745-1756 ◽  
Author(s):  
R L Heimark ◽  
M Degner ◽  
S M Schwartz

Confluent cultures of aortic endothelial cells contain two different cell-cell adhesion mechanisms distinguished by their requirement for calcium during trypsinization and adhesion. A hybridoma clone was isolated producing a monoclonal antibody Ec6C10, which inhibits Ca2(+)-dependent adhesion of endothelial cells. There was no inhibition of Ca2(+)-independent adhesion of endothelial cells and only a minor effect on Ca2(+)-dependent adhesion of smooth muscle cells. Immunoblotting analysis shows that the antibody Ec6C10 recognizes a protein in endothelial but not epithelial cells with an apparent molecular weight of 135,000 in reducing conditions and 130,000 in non-reducing conditions. Monoclonal antibody Ec6C10 reacts with an antigen at the cell surface as shown by indirect immunofluorescence of confluent endothelial cells in a junctional pattern outlining the cobblestone morphology of the monolayer. Removal of extracellular calcium increased the susceptibility of the antigen recognized by antibody Ec6C10 to proteolysis by trypsin. The role of the Ca2(+)-dependent cell adhesion molecule in organization of the dense peripheral microfilament band in confluent endothelial cells was examined by adjusting the level of extracellular calcium to modulate cell-cell contact. Addition of the monoclonal antibody Ec6C10 at the time of the calcium switch inhibited the extent of formation of the peripheral F-actin band. These results suggest an association between cell-cell contact and the peripheral F-actin band potentially through the Ca2(+)-dependent CAM.


2017 ◽  
Vol 114 (29) ◽  
pp. E5835-E5844 ◽  
Author(s):  
Caitlin Collins ◽  
Aleksandra K. Denisin ◽  
Beth L. Pruitt ◽  
W. James Nelson

Mechanical cues are sensed and transduced by cell adhesion complexes to regulate diverse cell behaviors. Extracellular matrix (ECM) rigidity sensing by integrin adhesions has been well studied, but rigidity sensing by cadherins during cell adhesion is largely unexplored. Using mechanically tunable polyacrylamide (PA) gels functionalized with the extracellular domain of E-cadherin (Ecad-Fc), we showed that E-cadherin–dependent epithelial cell adhesion was sensitive to changes in PA gel elastic modulus that produced striking differences in cell morphology, actin organization, and membrane dynamics. Traction force microscopy (TFM) revealed that cells produced the greatest tractions at the cell periphery, where distinct types of actin-based membrane protrusions formed. Cells responded to substrate rigidity by reorganizing the distribution and size of high-traction-stress regions at the cell periphery. Differences in adhesion and protrusion dynamics were mediated by balancing the activities of specific signaling molecules. Cell adhesion to a 30-kPa Ecad-Fc PA gel required Cdc42- and formin-dependent filopodia formation, whereas adhesion to a 60-kPa Ecad-Fc PA gel induced Arp2/3-dependent lamellipodial protrusions. A quantitative 3D cell–cell adhesion assay and live cell imaging of cell–cell contact formation revealed that inhibition of Cdc42, formin, and Arp2/3 activities blocked the initiation, but not the maintenance of established cell–cell adhesions. These results indicate that the same signaling molecules activated by E-cadherin rigidity sensing on PA gels contribute to actin organization and membrane dynamics during cell–cell adhesion. We hypothesize that a transition in the stiffness of E-cadherin homotypic interactions regulates actin and membrane dynamics during initial stages of cell–cell adhesion.


2015 ◽  
Vol 210 (7) ◽  
pp. 1065-1074 ◽  
Author(s):  
Julie M. Bianchini ◽  
Khameeka N. Kitt ◽  
Martijn Gloerich ◽  
Sabine Pokutta ◽  
William I. Weis ◽  
...  

As part of the E-cadherin–β-catenin–αE-catenin complex (CCC), mammalian αE-catenin binds F-actin weakly in the absence of force, whereas cytosolic αE-catenin forms a homodimer that interacts more strongly with F-actin. It has been concluded that cytosolic αE-catenin homodimer is not important for intercellular adhesion because E-cadherin/αE-catenin chimeras thought to mimic the CCC are sufficient to induce cell–cell adhesion. We show that, unlike αE-catenin in the CCC, these chimeras homodimerize, bind F-actin strongly, and inhibit the Arp2/3 complex, all of which are properties of the αE-catenin homodimer. To more accurately mimic the junctional CCC, we designed a constitutively monomeric chimera, and show that E-cadherin–dependent cell adhesion is weaker in cells expressing this chimera compared with cells in which αE-catenin homodimers are present. Our results demonstrate that E-cadherin/αE-catenin chimeras used previously do not mimic αE-catenin in the native CCC, and imply that both CCC-bound monomer and cytosolic homodimer αE-catenin are required for strong cell–cell adhesion.


1996 ◽  
Vol 109 (5) ◽  
pp. 1009-1016
Author(s):  
S. Funamoto ◽  
H. Ochiai

The gp64 protein of Polysphondylium pallidum has been shown to mediate EDTA-stable cell-cell adhesion. To explore the functional role of gp64, we made an antisense RNA expression construct designed to prevent the gene expression of gp64; the construct was introduced into P. pallidum cells and the transformants were characterised. The antisense RNA-expressing clone L3mc2 which had just been harvested at the growth phase tended to re-form in aggregates smaller in size than did the parental cells in either the presence or absence of 10 mM EDTA. In contrast, 6.5-hour starved L3mc2 cells remained considerably dissociated from each other after 5 minutes gyrating, although aggregation gradually increased by 50% during a further 55 minutes gyrating in the presence of 10 mM EDTA. Correspondingly, L3mc2 lacked specifically the cell-cell adhesion protein, gp64. We therefore conclude that the gp64 protein is involved in forming the EDTA-resistant cell-cell contact. In spite of the absence of gp64, L3mc2 exhibited normal developmental processes, a fact which demonstrates that another cell-cell adhesion system exists in the development of Polysphondylium. This is the first report in which an antisense RNA technique was successfully applied to Polysphondylium.


1998 ◽  
Vol 111 (8) ◽  
pp. 1071-1080 ◽  
Author(s):  
S.M. Reuver ◽  
C.C. Garner

Members of the SAP family of synapse-associated proteins have recently emerged as central players in the molecular organization of synapses. In this study, we have examined the mechanism that localizes one member, SAP97, to sites of cell-cell contact. Utilizing epithelial CACO-2 cells and fibroblast L-cells as model systems, we demonstrate that SAP97 is associated with the submembranous cortical cytoskeleton at cell-cell adhesion sites. Furthermore, we show that its localization into this structure is triggered by E-cadherin. Although SAP97 can be found in an E-cadherin/catenin adhesion complex, this interaction seems to be mediated by the attachment of SAP97 to the cortical cytoskeleton. Our results are consistent with a model in which SAP97 is recruited to sites of cell-cell contact via an E-cadherin induced assembly of the cortical cytoskeleton.


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