The RhoA Activator GEF-H1/Lfc Is a Transforming Growth Factor-β Target Gene and Effector That Regulates α-Smooth Muscle Actin Expression and Cell Migration

Tsapara, Anna; Luthert, Philip J.; Greenwood, John; Hill, Caroline S.; Matter, Karl; Balda, María S.

doi:10.1091/mbc.e09-07-0567

Cited by 89 publications

(89 citation statements)

References 68 publications

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“…Third, we showed that cell motility induced by RASSF1A depletion could be efficiently inhibited by GEFs activating RhoB, while dominant negative RhoBN19 mutant or siRhoB were able to increase cell motility. Noteworthy, in our settings, overexpressing RhoB-GEF, GEF-H1, restrained RASSF1A-induced cell migration, whereas previous studies had assigned a promigratory role to GEF-H1 (29,40). Conversely, GEF-H1 depletion (Fig.…”

Section: Discussionmentioning

confidence: 43%

RASSF1A Suppresses the Invasion and Metastatic Potential of Human Non–Small Cell Lung Cancer Cells by Inhibiting YAP Activation through the GEF-H1/RhoB Pathway

et al. 2016

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Inactivation of the tumor suppressor gene RASSF1A by promoter hypermethylation represents a key event underlying the initiation and progression of lung cancer. RASSF1A inactivation is also associated with poor prognosis and may promote metastatic spread. In this study, we investigated how RASSF1A inactivation conferred invasive phenotypes to human bronchial cells. RNAi-mediated silencing of RASSF1A induced epithelialto-mesenchymal transition (EMT), fomenting a motile and invasive cellular phenotype in vitro and increased metastatic prowess in vivo. Mechanistic investigations revealed that RASSF1A blocked tumor growth by stimulating cofilin/PP2A-mediated dephosphorylation of the guanine nucleotide exchange factor GEF-H1, thereby stimulating its ability to activate the antimetastatic small GTPase RhoB. Furthermore, RASSF1A reduced nuclear accumulation of the Hippo pathway transcriptional cofactor Yes-associated protein (YAP), which was reinforced by RhoB activation. Collectively, our results indicated that RASSF1 acts to restrict EMT and invasion by indirectly controlling YAP nuclear shuttling and activation through a RhoB-regulated cytoskeletal remodeling process, with potential implications to delay the progression of RASSF1-hypermethylated lung tumors. Cancer Res; 76(6);

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Section: Discussionmentioning

confidence: 43%

RASSF1A Suppresses the Invasion and Metastatic Potential of Human Non–Small Cell Lung Cancer Cells by Inhibiting YAP Activation through the GEF-H1/RhoB Pathway

et al. 2016

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“…The latter effect involves induction of cyclin D1, mediated by RhoA, and requires the Y-box transcription factor ZONAB. Recently, GEF-H1 was also identified as a key regulator of smooth muscle expression and fibrotic processes in retinal pigment epithelium (73). Interestingly, GEF-H1 is also a target of the proliferative MEK/ERK pathway (13,31).…”

Section: Discussionmentioning

confidence: 99%

The Epidermal Growth Factor Receptor Mediates Tumor Necrosis Factor-α-induced Activation of the ERK/GEF-H1/RhoA Pathway in Tubular Epithelium

Kakiashvili¹,

Dan²,

Vandermeer

et al. 2011

Journal of Biological Chemistry

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Tumor necrosis factor (TNF)-␣ induces cytoskeleton and intercellular junction remodeling in tubular epithelial cells; the underlying mechanisms, however, are incompletely explored. We have previously shown that ERK-mediated stimulation of the RhoA GDP/GTP exchange factor GEF-H1/Lfc is critical for TNF-␣-induced RhoA stimulation. Here we investigated the upstream mechanisms of ERK/GEF-H1 activation. Surprisingly, TNF-␣-induced ERK and RhoA stimulation in tubular cells were prevented by epidermal growth factor receptor (EGFR) inhibition or silencing. TNF-␣ also enhanced phosphorylation of the EGFR. EGF treatment mimicked the effects of TNF-␣, as it elicited potent, ERK-dependent GEF-H1 and RhoA activation. Moreover, EGF-induced RhoA activation was prevented by GEF-H1 silencing, indicating that GEF-H1 is a key downstream effector of the EGFR. The TNF-␣-elicited EGFR, ERK, and RhoA stimulation were mediated by the TNF-␣ convertase enzyme (TACE) that can release EGFR ligands. Further, EGFR transactivation also required the tyrosine kinase Src, as Src inhibition prevented TNF-␣-induced activation of the EGFR/ERK/ GEF-H1/RhoA pathway. Importantly, a bromodeoxyuridine (BrdU) incorporation assay and electric cell substrate impedance-sensing (ECIS) measurements revealed that TNF-␣ stimulated cell growth in an EGFR-dependent manner. In contrast, TNF-␣-induced NFB activation was not prevented by EGFR or Src inhibition, suggesting that TNF-␣ exerts both EGFR-dependent and -independent effects. In summary, in the present study we show that the TNF-␣-induced activation of the ERK/GEF-H1/RhoA pathway in tubular cells is mediated through Src-and TACE-dependent EGFR activation. Such a mechanism could couple inflammatory and proliferative stimuli and, thus, may play a key role in the regulation of wound healing and fibrogenesis.

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“…As Xlfc-MO has no effect on tissue stiffness and does not perturb Xenopus development, it is unlikely that Xlfc regulates the stiffness changes observed in the Xenopus embryo . RhoGEF H1/Lfc is involved in regulating cell contractility during mitosis (Bakal et al, 2005), spine formation during dendrite formation (Ryan et al, 2005) and is a gene target of TGF signaling (Tsapara et al, 2010). Much work remains to identify these roles, whether they require reduced microtubule mass or other triggering mechanisms, using both in vitro and in vivo systems.…”

Section: Molecular Contribution Of the Cytoskeleton To Embryonic Tissmentioning

confidence: 99%

Macroscopic stiffening of embryonic tissues via microtubules, RhoGEF and the assembly of contractile bundles of actomyosin

et al. 2010

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SUMMARYDuring morphogenesis, forces generated by cells are coordinated and channeled by the viscoelastic properties of the embryo. Microtubules and F-actin are considered to be two of the most important structural elements within living cells accounting for both force production and mechanical stiffness. In this paper, we investigate the contribution of microtubules to the stiffness of converging and extending dorsal tissues in Xenopus laevis embryos using cell biological, biophysical and embryological techniques. Surprisingly, we discovered that depolymerizing microtubules stiffens embryonic tissues by three-to fourfold. We attribute tissue stiffening to Xlfc, a previously identified RhoGEF, which binds microtubules and regulates the actomyosin cytoskeleton. Combining drug treatments and Xlfc activation and knockdown lead us to the conclusion that mechanical properties of tissues such as viscoelasticity can be regulated through RhoGTPase pathways and rule out a direct contribution of microtubules to tissue stiffness in the frog embryo. We can rescue nocodazole-induced stiffening with drugs that reduce actomyosin contractility and can partially rescue morphogenetic defects that affect stiffened embryos. We support these conclusions with a multi-scale analysis of cytoskeletal dynamics, tissue-scale traction and measurements of tissue stiffness to separate the role of microtubules from RhoGEF activation. These findings suggest a re-evaluation of the effects of nocodazole and increased focus on the role of Rho family GTPases as regulators of the mechanical properties of cells and their mechanical interactions with surrounding tissues. , 2000). Disruption of microtubules can also increase cellular tension (Danowski, 1989;Dennerll et al., 1988; Kolodney and Elson, 1995;Stamenovic et al., 2002b;Wang et al., 2001) by activating actomyosin contraction; but it is unknown whether activation of actomyosin in the absence of microtubules is achieved through mechanical interactions or via signaling pathways (Birukova et al., 2004;Chang et al., 2008; Kolodney and Elson, 1995;Verin et al., 2001). Microtubules can signal to actomyosin through Rho family GTPases. RhoGTPases are key elements in the regulation of the actomyosin cytoskeleton in both cultured cells and during morphogenesis (Hall, 2005;Settleman, 2001). The Rho family members are well known to control cellular processes such as actin assembly, as well as the organization of myosin II-mediated contractility into lamellipodia and filopodia to guide cell migration and cell contractility. RhoGTPases can also regulate processes such as assembly of ECM (Dzamba et al., 2009) and the bulk elasticity of tissues through control of cortical actomyosin contractility and cell traction forces (Paszek et al., 2005). Thus, disrupting microtubules with drugs such as nocodazole may have inadvertently been testing not the role of microtubules but the role of RhoGTPases in development.In this paper, we first investigate the contribution of microtubules to tissue stiffness and how mic...

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The RhoA Activator GEF-H1/Lfc Is a Transforming Growth Factor-β Target Gene and Effector That Regulates α-Smooth Muscle Actin Expression and Cell Migration

Cited by 89 publications

References 68 publications

RASSF1A Suppresses the Invasion and Metastatic Potential of Human Non–Small Cell Lung Cancer Cells by Inhibiting YAP Activation through the GEF-H1/RhoB Pathway

RASSF1A Suppresses the Invasion and Metastatic Potential of Human Non–Small Cell Lung Cancer Cells by Inhibiting YAP Activation through the GEF-H1/RhoB Pathway

The Epidermal Growth Factor Receptor Mediates Tumor Necrosis Factor-α-induced Activation of the ERK/GEF-H1/RhoA Pathway in Tubular Epithelium

Macroscopic stiffening of embryonic tissues via microtubules, RhoGEF and the assembly of contractile bundles of actomyosin

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