Epithelial junctions and Rho family GTPases: the zonular signalosome

Citi, Sandra; Guerrera, Diego; Spadaro, Domenica; Shah, Jimit

doi:10.4161/21541248.2014.973760

Cited by 159 publications

(156 citation statements)

References 183 publications

(164 reference statements)

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“…38 Indeed, our results provide evidence that cingulin is a scaffold protein for GEF-H1 and p114RhoGEF in endothelial cells because junctional labeling for these GEFs was lost in CGN −/− tissues. The emerging roles of GEF-H1 and p114RhoGEF in regulating endothelial barrier function [20][21][22] support the idea of a mechanism based on the regulation of Rho GTPases.…”

Section: Discussionmentioning

confidence: 70%

Evidence That Cingulin Regulates Endothelial Barrier Function In Vitro and In Vivo

Schossleitner

Rauscher

Gröger

et al. 2016

ATVB

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Objective-Cingulin is a cytoplasmic component of tight junctions. Although modulation of cingulin levels in cultured epithelial model systems has no significant effect on barrier function, evidence from cingulin knockout mice suggests that cingulin may be involved in the regulation of the behavior of epithelial or endothelial cells. Here, we investigate the role of cingulin in the barrier function of endothelial cells. Approach and Results-We show that cingulin is expressed in human endothelial cells of the skin, brain, and lung in vivo and in vitro. Endothelial cingulin colocalizes and coimmunoprecipitates with the tight junction proteins zonula occludens-1 and guanine nucleotide exchange factor-H1. Cingulin overexpression in human umbilical vein endothelial cell induces tight junction formation, increases transendothelial electric resistance, and strengthens barrier function for low and high molecular weight tracers. In contrast, cultured endothelial cells lacking cingulin are more permeable for low molecular weight tracers. In cingulin knockout mice, neurons of the area postrema and Purkinje cells show an increased uptake of small molecular weight tracers indicating decreased barrier function at these sites. The expression of cingulin in endothelial cells has been poorly characterized because early studies showed a low abundance of cingulin in endothelial cells when compared with epithelia. 18,19 However, the recently characterized role of GEF-H1 in regulating endothelial permeability 20,21 raises the possibility that cingulin is a key regulator of endothelial barrier function. Conclusions-WeHere, we studied the expression and molecular environment of cingulin in different types of endothelial cells. Furthermore, we characterized the effects of exogenous cingulin expression or deletion of the cingulin head domain on the expression of claudin-5 and endothelial barrier function and analyzed barrier function in cingulin-deficient mice. The results indicate that expression levels of cingulin contribute to regulating endothelial barrier function. Materials and MethodsMaterials and Methods are available in the online-only Data Supplement. Results Cingulin Is Localized at Human Endothelial TJ In SituWe analyzed the expression of cingulin in different vascular beds by immunohistochemistry. Endothelial cells of large and small-sized veins and arteries in human skin, lung, and brain tissues stained positive with anticingulin antibodies ( Figure 1A). By immunofluorescence, cingulin labeling was detected in close proximity of VE-cadherin labeling with a Pearson correlation coefficient of 0.11, but was colocalizing with ZO-1 labeling resulting in a Pearson correlation coefficient of 0.31 ( Figure 1B), supporting the notion that cingulin is associated with TJ of endothelial cells. 22 Analysis of mRNA expression levels of cingulin relative to VE-cadherin in different tissues and vessels showed that cingulin expression was detectable in the brain, the vena cava, and the aorta, whereas no expression was detected in muscle an...

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Section: Discussionmentioning

confidence: 70%

Evidence That Cingulin Regulates Endothelial Barrier Function In Vitro and In Vivo

Schossleitner

Rauscher

Gröger

et al. 2016

ATVB

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“…For example, thrombin stimulation of vascular ECs causes barrier disruption, but it simultaneously triggers auto-recovery mechanisms by activating Rap1-Rac1-dependent down-regulation of Rho signaling, stimulation of peripheral cytoskeletal dynamics, and resealing of intercellular gaps (43). Other mechanisms involve activation of the negative regulator of RhoA, p190RhoGAP, at cell junctions and focal adhesions (44,45), or cell junction-restricted activation of Rac1-specific GEF Trio in epithelial monolayers (23). The abundance of negative feedback of Rho regulation mechanisms in vascular ECs, including the GEF-H1-cingulin axis, emphasizes a critical role for small GTPase activity switch as a part of biphasic vascular endothelial permeability response to a variety of vasoactive stimuli, which ensures dynamic regulation of EC barrier in vivo.…”

Section: Discussionmentioning

confidence: 99%

“…Cingulin is a protein localized in the cytoplasmic compartment of the TJ in epithelial and endothelial cells and is involved in TJ reassembly (23). The cingulin forms a parallel homodimer of two 140-kDa subunits, each comprising a globular Head domain, a coiled-coil "rod," and a small globular tail (24).…”

mentioning

confidence: 99%

Role of Cingulin in Agonist-induced Vascular Endothelial Permeability

Tian

Gawlak

Tian

et al. 2016

Journal of Biological Chemistry

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Agonist-induced activation of Rho GTPase signaling leads to endothelial cell (EC) permeability and may culminate in pulmonary edema, a devastating complication of acute lung injury. Cingulin is an adaptor protein first discovered in epithelium and is involved in the organization of the tight junctions. This study investigated the role of cingulin in control of agonist-induced lung EC permeability via interaction with RhoA-specific activator GEF-H1. The siRNA-induced cingulin knockdown augmented thrombin-induced EC permeability monitored by measurements of transendothelial electrical resistance and endothelial cell permeability for macromolecules. Increased thrombin-induced permeability in ECs with depleted cingulin was associated with increased activation of GEF-H1 and RhoA detected in pulldown activation assays. Increased GEF-H1 association with cingulin was essential for down-regulation of thrombin-induced RhoA barrier disruptive signaling. Using cingulin-truncated mutants, we determined that GEF-H1 interaction with the rod ؉ tail domain of cingulin was required for inactivation of GEF-H1 and endothelial cell barrier preservation. The results demonstrate the role for association of GEF-H1 with cingulin as the mechanism of RhoA pathway inactivation and rescue of EC barrier after agonist challenge.

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“…In case of epithelial junctions, the term "zonular signalosome" has been introduced to summarize the complex consisting of zonular proteins and different RhoGEFs and RhoGAPs that assure the anchoring of the junction as well as its contacts with the cytoskeleton. 37 More direct data are available in neural studies. Synaptogenesis of hippocampal neurons was shown to depend both on the RacGEF Tiam1 and on the RacGAP Bcr.…”

Section: Are Gaps Lonely Players?mentioning

confidence: 99%

The neglected terminators: Rho family GAPs in neutrophils

Csépányi-Kömi

Pásztor

Bartos

et al. 2018

Eur J Clin Investigation

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Background: GTPase-activating proteins (GAPs) accelerate the rate of hydrolysis of GTP bound to small GTPases, thereby limiting the prevalence and concentration of the active, GTP-bound form of these proteins. The large number of potential GAPs acting on members of the Rho family of small GTPases raises the question of specificity or redundancy. Results: In this review, we summarize experimental data obtained on the role of Rho family GAPs in neutrophils, highlight cases where more than one GAP is involved in a physiological function and show examples that GAPs can be involved not only in termination but also in initiation of cellular processes. We demonstrate that the expression-level regulation of GAPs may also occur in shortliving cells such as neutrophils. Finally, we provide insight into the existence and structure of molecular complexes in which Rho family GAPs are involved. Conclusion: GAPs play more complex and varied roles than being simple terminators of cellular processes. K E Y W O R D SGTPase activating proteins, Rho-family small GTPases, neutrophils

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Epithelial junctions and Rho family GTPases: the zonular signalosome

Cited by 159 publications

References 183 publications

Evidence That Cingulin Regulates Endothelial Barrier Function In Vitro and In Vivo

Evidence That Cingulin Regulates Endothelial Barrier Function In Vitro and In Vivo

Role of Cingulin in Agonist-induced Vascular Endothelial Permeability

The neglected terminators: Rho family GAPs in neutrophils

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