scholarly journals Quantitative cell polarity imaging defines leader-to-follower transitions during collective migration and the key role of microtubule-dependent adherens junction formation

Development ◽  
2014 ◽  
Vol 141 (6) ◽  
pp. 1282-1291 ◽  
Author(s):  
C. Revenu ◽  
S. Streichan ◽  
E. Dona ◽  
V. Lecaudey ◽  
L. Hufnagel ◽  
...  
Keyword(s):  
Cell Polarity ◽  
Adherens Junction ◽  
Collective Migration ◽  
Junction Formation

scholarly journals DLG-1 Is a MAGUK Similar to SAP97 and Is Required for Adherens Junction Formation

2001 ◽  
Vol 12 (11) ◽  
pp. 3465-3475 ◽  
Author(s):  
Bonnie L. Firestein ◽  
Christopher Rongo
Keyword(s):  
Cell Polarity ◽  
Adherens Junctions ◽  
Adherens Junction ◽  
Cell Junctions ◽  
Permeability Barrier ◽  
Cortical Actin ◽  
Interaction Domain ◽  
Amino Terminal ◽  
Junction Formation ◽  
And Function

Cellular junctions are critical for intercellular communication and for the assembly of cells into tissues. Cell junctions often consist of tight junctions, which form a permeability barrier and prevent the diffusion of lipids and proteins between cell compartments, and adherens junctions, which control the adhesion of cells and link cortical actin filaments to attachment sites on the plasma membrane. Proper tight junction formation and cell polarity require the function of membrane-associated guanylate kinases (MAGUKs) that contain the PDZ protein-protein interaction domain. In contrast, less is known about how adherens junctions are assembled. Here we describe how the PDZ-containing protein DLG-1 is required for the proper formation and function of adherens junctions in Caenorhabditis elegans. DLG-1 is a MAGUK protein that is most similar in sequence to mammalian SAP97, which is found at both synapses of the CNS, as well as at cell junctions of epithelia. DLG-1 is localized to adherens junctions, and DLG-1 localization is mediated by an amino-terminal domain shared with SAP97 but not found in other MAGUK family members. DLG-1 recruits other proteins and signaling molecules to adherens junctions, while embryos that lack DLG-1 fail to recruit the proteins AJM-1 and CPI-1 to adherens junctions. DLG-1 is required for the proper organization of the actin cytoskeleton and for the morphological elongation of embryos. In contrast to other proteins that have been observed to affect adherens junction assembly and function, DLG-1 is not required to maintain cell polarity. Our results suggest a new function for MAGUK proteins distinct from their role in cell polarity.

scholarly journals Cell polarity and adherens junction formation inhibit epithelial Fas cell death receptor signaling

2018 ◽  
Vol 217 (11) ◽  
pp. 3839-3852 ◽  
Author(s):  
Laurent Gagnoux-Palacios ◽  
Hala Awina ◽  
Stéphane Audebert ◽  
Aurélie Rossin ◽  
Magali Mondin ◽  
...  
Keyword(s):  
Cell Death ◽  
Cell Polarity ◽  
Fas Ligand ◽  
Death Receptor ◽  
Adherens Junction ◽  
Cellular Level ◽  
Protection Mechanism ◽  
Junction Formation ◽  
Additional Cell ◽  
E Cadherin

Finely tuned regulation of epithelial cell death maintains tissue integrity and homeostasis. At the cellular level, life and death decisions are controlled by environmental stimuli such as the activation of death receptors. We show that cell polarity and adherens junction formation prevent proapoptotic signals emanating from the Fas death receptor. Fas is sequestered in E-cadherin actin-based adhesion structures that are less able to induce downstream apoptosis signaling. Using a proteomic-based approach, we find that the polarity molecule Dlg1 interacts with the C-terminal PDZ-binding site in Fas and that this interaction decreases formation of the death-inducing complex upon engagement with Fas ligand (FasL), thus acting as an additional cell death protection mechanism. We propose that E-cadherin and Dlg1 inhibit FasL-induced cell death by two complementary but partially independent mechanisms that help to maintain epithelial homeostasis by protecting normal polarized epithelia from apoptosis. When polarity is lost, the Fas–cadherin–Dlg1 antiapoptotic complex is disrupted, and FasL can promote the elimination of compromised nonpolarized cells.

scholarly journals Golgi-associated cPLA2α Regulates Endothelial Cell–Cell Junction Integrity by Controlling the Trafficking of Transmembrane Junction Proteins

2009 ◽  
Vol 20 (19) ◽  
pp. 4225-4234 ◽  
Author(s):  
Elsa Regan-Klapisz ◽  
Vincent Krouwer ◽  
Miriam Langelaar-Makkinje ◽  
Laxman Nallan ◽  
Michael Gelb ◽  
...  
Keyword(s):  
Endothelial Cell ◽  
Intracellular Trafficking ◽  
Adherens Junction ◽  
Cell Junctions ◽  
Cell Junction ◽  
Tight Junction Formation ◽  
Junction Formation ◽  
Junction Proteins ◽  
Cell Cell

In endothelial cells specifically, cPLA2α translocates from the cytoplasm to the Golgi complex in response to cell confluence. Considering the link between confluence and cell–cell junction formation, and the emerging role of cPLA2α in intracellular trafficking, we tested whether Golgi-associated cPLA2α is involved in the trafficking of junction proteins. Here, we show that the redistribution of cPLA2α from the cytoplasm to the Golgi correlates with adherens junction maturation and occurs before tight junction formation. Disruption of adherens junctions using a blocking anti-VE-cadherin antibody reverses the association of cPLA2α with the Golgi. Silencing of cPLA2α and inhibition of cPLA2α enzymatic activity using various inhibitors result in the diminished presence of the transmembrane junction proteins VE-cadherin, occludin, and claudin-5 at cell–cell contacts, and in their accumulation at the Golgi. Altogether, our data support the idea that VE-cadherin triggers the relocation of cPLA2α to the Golgi and that in turn, Golgi-associated cPLA2α regulates the transport of transmembrane junction proteins through or from the Golgi, thereby controlling the integrity of endothelial cell–cell junctions.

scholarly journals Phosphorylation of Rab11-FIP2 regulates polarity in MDCK cells

2012 ◽  
Vol 23 (12) ◽  
pp. 2302-2318 ◽  
Author(s):  
Lynne A. Lapierre ◽  
Kenya M. Avant ◽  
Cathy M. Caldwell ◽  
Asli Oztan ◽  
Gerard Apodaca ◽  
...  
Keyword(s):  
Tight Junctions ◽  
Mdck Cell ◽  
Mdck Cells ◽  
Adherens Junction ◽  
Cellular Polarity ◽  
Interacting Protein ◽  
P120 Catenin ◽  
Myosin Vb ◽  
Darby Canine Kidney

The Rab11 effector Rab11-family interacting protein 2 (Rab11-FIP2) regulates transcytosis through its interactions with Rab11a and myosin Vb. Previous studies implicated Rab11-FIP2 in the establishment of polarity in Madin–Darby canine kidney (MDCK) cells through phosphorylation of Ser-227 by MARK2. Here we examine the dynamic role of Rab11-FIP2 phosphorylation on MDCK cell polarity. Endogenous Rab11-FIP2 phosphorylated on Ser-227 coalesces on vesicular plaques during the reestablishment of polarity after either monolayer wounding or calcium switch. Whereas expression of the nonphosphorylatable Rab11-FIP2(S227A) elicits a loss in lumen formation in MDCK cell cysts grown in Matrigel, the putative pseudophosphorylated Rab11-FIP2(S227E) mutant induces the formation of cysts with multiple lumens. On permeable filters, Rab11-FIP2(S227E)–expressing cells exhibit alterations in the composition of both the adherens and tight junctions. At the adherens junction, p120 catenin and K-cadherin are retained, whereas the majority of the E-cadherin is lost. Although ZO-1 is retained at the tight junction, occludin is lost and the claudin composition is altered. Of interest, the effects of Rab11-FIP2 on cellular polarity did not involve myosin Vb or Rab11a. These results indicate that Ser-227 phosphorylation of Rab11-FIP2 regulates the composition of both adherens and tight junctions and is intimately involved in the regulation of polarity in epithelial cells.

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