Plakophilin 4 controls the spatio-temporal activity of RhoA at adherens junctions to promote cortical actin ring formation and tissue tension
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE255172 | GEO | 2024/06/24
REPOSITORIES: GEO
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Project description:Endothelial barrier integrity is ensured by the stability of the adherens junction (AJ) complexes comprised of VE-cadherin as well as accessory proteins such as β-catenin and p120-catenin. Disruption of the endothelial barrier due to disassembly of AJs results in tissue edema and the influx of inflammatory cells. Using three-dimensional structured illumination microscopy (3D- SIM), we found that the mitochondrial protein Mitofusin-2 (Mfn2) co-localizes at the plasma membrane with VE-cadherin and β-catenin in endothelial cells during homeostasis. Upon inflammatory stimulation, Mfn2 is sulfenylated, the Mfn2/β-catenin complex disassociates from the AJs and translocates into the nucleus where Mfn2 negatively regulates the transcriptional activity of β-catenin. Endothelial-specific deletion of Mfn2 resulted in inflammatory injury, indicating an anti-inflammatory role of Mfn2 in vivo. Our results suggest that Mfn2 acts in a non- canonical manner to suppress the inflammatory response by stabilizing cell-cell adherens junctions and by binding to the transcriptional activator β-catenin.
2023-04-18 | GSE148987 | GEO
Project description:Rho family small GTPases serve as molecular switches in the regulation of diverse cellular functions including actin cytoskeleton remodeling, cell migration, gene transcription, and cell proliferation. Importantly, Rho overexpression is frequently seen in many carcinomas. However, published studies have almost invariably utilized immortal or tumorigenic cell lines to study Rho GTPase functions and there are no studies on the potential of Rho small GTPase to overcome senescence checkpoints and induce preneoplastic transformation of human mammary epithelial cells (hMECs). We found that ectopic expression of wild-type RhoA as well as a constitutively-active RhoA mutant (G14V) in primary hMEC strains led to their immortalization and preneoplastic transformation. Significantly, RhoA-T37A mutant, known to be incapable of interacting with many well known Rho-effectors ,was also capable of immortalizing hMECs.Our results demonstrate that RhoA can induce the preneoplastic transformation of hMECs by altering multiple pathways linked cellular transformation and breast cancer. Through microarray analysis, we want to identify genes and pathways linked to RhoA induced hMECs immortalization. Experiment Overall Design: 4 samples, in triplicate analyses per sample.
2008-10-26 | E-GEOD-12917 | biostudies-arrayexpress
Project description:Background: Negative-pressure wound therapy has become widely available in modern chronic wound cares. Accelerated keratinocyte (HaCaT cell) movements and decreased E-cadherin expressions induced by the applied negative pressure gradient of 125 mmHg (NP) have been reported in previous studies. However, the molecular mechanism for E-cadherin regulations under NP remains unexplored. We highlighted the signal transduction involved in NP-induced E-cadherin regulation for keratinocytes in the study. Results: Microarray results showed that catenin 1 (CTNND1) gene, the gene encoding the p120-catenin (p120ctn) in cell-cell junctions, was significantly (p = 0.0005) upregulated in HaCaT cells under NP for 12 hours in comparison with those at ambient pressure (AP). Cell fractionations and immunoblotting data showed that NP increased p120ctn phosphorylation, and resulted in p120ctn translocation from the plasma membrane to the cytoplasm. Fluorescent stains suggested that NP diminished the co-localization of p120ctn and E-cadherin on the plasma membrane. Similar phenomenon was also observed in the cells with overexpressed p120ctn at NP. Interestingly, overexpression of dN- p120ctn, a deletion mutant of p120ctn without the N-terminal phosphorylation sites, restored the adherens junctions (AJ) at NP. Knockdown of p120ctn with lentiviral small hairpin RNA not only diminished E-cadherin expressions but also accelerated cell movement at AP. Conclusions: Phosphorylation of p120ctn is endowed to respond rapidly to NP and contributes to the AJ disassembly. This NP-induced E-cadherin downregulation can possibly accelerate wound-healing process. Conclusions: Phosphorylation of p120ctn is endowed to respond rapidly to NP and contributes to the AJ disassembly. This NP-induced E-cadherin downregulation can possibly accelerate wound-healing process.
2015-12-31 | GSE70512 | GEO
Project description:Background: Negative-pressure wound therapy has become widely available in modern chronic wound cares. Accelerated keratinocyte (HaCaT cell) movements and decreased E-cadherin expressions induced by the applied negative pressure gradient of 125 mmHg (NP) have been reported in previous studies. However, the molecular mechanism for E-cadherin regulations under NP remains unexplored. We highlighted the signal transduction involved in NP-induced E-cadherin regulation for keratinocytes in the study. Results: Microarray results showed that catenin 1 (CTNND1) gene, the gene encoding the p120-catenin (p120ctn) in cell-cell junctions, was significantly (p = 0.0005) upregulated in HaCaT cells under NP for 12 hours in comparison with those at ambient pressure (AP). Cell fractionations and immunoblotting data showed that NP increased p120ctn phosphorylation, and resulted in p120ctn translocation from the plasma membrane to the cytoplasm. Fluorescent stains suggested that NP diminished the co-localization of p120ctn and E-cadherin on the plasma membrane. Similar phenomenon was also observed in the cells with overexpressed p120ctn at NP. Interestingly, overexpression of dN- p120ctn, a deletion mutant of p120ctn without the N-terminal phosphorylation sites, restored the adherens junctions (AJ) at NP. Knockdown of p120ctn with lentiviral small hairpin RNA not only diminished E-cadherin expressions but also accelerated cell movement at AP. Conclusions: Phosphorylation of p120ctn is endowed to respond rapidly to NP and contributes to the AJ disassembly. This NP-induced E-cadherin downregulation can possibly accelerate wound-healing process. Conclusions: Phosphorylation of p120ctn is endowed to respond rapidly to NP and contributes to the AJ disassembly. This NP-induced E-cadherin downregulation can possibly accelerate wound-healing process. HaCaT cells under negative pressure (NP) gradient of 125 mmHg for 12 hours in comparison with those at ambient pressure (AP) were tested for RNA extraction and hybridization on Affymetrix microarrays. The experiments have been biological replicated three times. The differential expression gene between NP and AP were selected and validated with qPCR method.
2015-12-31 | E-GEOD-70512 | biostudies-arrayexpress
Project description:Prior studies have implicated myosin light chain kinase (MLCK) in the regulation of aqua-porin-2 (AQP2) in the renal collecting duct. To discover signaling targets of MLCK, we deleted the Mylk- gene to obtain MLCK-null mpkCCD cells and carried out comprehensive phosphopro-teomics using the SILAC method for quantification. Only 107 phosphopeptides were changed in abundance by MLCK deletion out of 1743 quantified over multiple replicates (29 decreased and 78 increased). One of the decreased phosphopeptides corresponded to the canonical target site in myosin regulatory light chain (MLC). Network analysis indicated that targeted phosphopro-teins clustered into distinct structural/functional groups: “acto-myosin,” “signaling,” “nuclear envelope,” “gene transcription,” “mRNA processing,” “energy metabolism,” “intermediate fila-ments,” “adherens junctions” and “tight junctions.” There was significant overlap between the derived MLCK signaling network and a previously determined PKA signaling network. Phalloidin labeling revealed that MLCK deletion inhibited the normal effect of vasopressin to depolymer-ize F-actin. Immunocytochemistry and electron microscopy demonstrated a defect in pro-cessing of early endosomes to late endosomes. In contrast, surface biotinylation studies showed no effect of MLCK deletion on AQP2 endocytosis. We conclude that MLCK is part of a multi-component signaling pathway that includes much more than simple regulation of conven-tional non-muscle myosins through MLC phosphorylation. Furthermore, vasopressin signaling in collecting duct cells involves both MLCK-dependent signaling and PKA-dependent signaling, which display significant overlap. Mapping MLCK targets revealed potential roles in both nu-cleus and cytoplasm. The latter includes proteins that regulate both actin polymerization and AQP2-endosomal processing from early to late endosomes.
2020-03-04 | PXD014985 | Pride
Project description:Rho family small GTPases serve as molecular switches in the regulation of diverse cellular functions including actin cytoskeleton remodeling, cell migration, gene transcription, and cell proliferation. Importantly, Rho overexpression is frequently seen in many carcinomas. However, published studies have almost invariably utilized immortal or tumorigenic cell lines to study Rho GTPase functions and there are no studies on the potential of Rho small GTPase to overcome senescence checkpoints and induce preneoplastic transformation of human mammary epithelial cells (hMECs). We found that ectopic expression of wild-type RhoA as well as a constitutively-active RhoA mutant (G14V) in primary hMEC strains led to their immortalization and preneoplastic transformation. Significantly, RhoA-T37A mutant, known to be incapable of interacting with many well known Rho-effectors ,was also capable of immortalizing hMECs.Our results demonstrate that RhoA can induce the preneoplastic transformation of hMECs by altering multiple pathways linked cellular transformation and breast cancer. Through microarray analysis, we want to identify genes and pathways linked to RhoA induced hMECs immortalization.
2008-09-26 | GSE12917 | GEO
Project description:Background: Cancer metastasis is dependent on cell migration. Several mechanisms, including epithelial-to-mesenchymal transition (EMT) and actin fiber formation, could be involved in cancer cell migration. As a downstream effector of the Hippo signaling pathway, transcriptional coactivator with PDZbinding motif (TAZ) is recognized as a key mediator of the metastatic ability of breast cancer cells. We aimed to examine whether TAZ affects the migration of breast cancer cells through the regulation of EMT or actin cytoskeleton. Methods: MCF-7 and MDA-MB-231 cells were treated with siRNA to attenuate TAZ abundance. Transwell migration assay and scratch wound healing assay were performed to study the effects of TAZ knockdown on cancer cell migration. Fluorescence microscopy was conducted to examine the vinculin and phalloidin. Semiquantitative immunoblotting and quantitative real-time PCR were performed to study the expression of small GTPases and kinases. Changes in the expression of genes associated with cell migration were examined through next-generation sequencing. Results: TAZ-siRNA treatment reduced TAZ abundance in MCF-7 and MDA-MB- 231 breast cancer cells, which was associated with a significant decrease in cell migration. TAZ knockdown increased the expression of fibronectin, but it did not exhibit the typical pattern of EMT progression. TGF-b treatment in MDA-MB-231 cells resulted in a reduction in TAZ and an increase in fibronectin levels. However, it paradoxically promoted cell migration, suggesting that EMT is unlikely to be involved in the decreased migration of breast cancer cells in response to TAZ suppression. RhoA, a small Rho GTPase protein, was significantly reduced in response to TAZ knockdown. This caused a decrease in the expression of the Rho-dependent downstream pathway, i.e., LIM kinase 1 (LIMK1), phosphorylated LIMK1/2, and phosphorylated cofilin, leading to actin depolymerization. Furthermore, myosin light chain kinase (MLCK) and phosphorylated MLC2 were significantly decreased in MDA-MB-231 cells with TAZ knockdown, inhibiting the assembly of stress fibers and focal adhesions. Conclusion: TAZ knockdown inhibits the migration of breast cancer cells by regulating the intracellular actin cytoskeletal organization. This is achieved, in part, by reducing the abundance of RhoA and Rho-dependent downstream kinase proteins, which results in actin depolymerization and the disassembly of stress fibers and focal adhesions.
2024-04-27 | GSE264547 | GEO
Project description:RHO subfamily of small GTPases comprise highly conserved family members RHOA, RHOB, and RHOC which cycle between GTP-bound 'active' and GDP-bound 'inactive' states. In the active form, RHO proteins interact with a variety of downstream effector proteins, controlling their activity and function. Many of the RHO subfamily effector proteins such as ROCK, PKN, and mDIA, are key regulators of actin cytoskeleton and cell motility. To identify novel effector proteins for RHOA,we carried out a GST-pulldown from heavy or light SILAC labelled HeLa cells using GST tagged GTP-bound RHOA, or GST alone control, as bait. Pulldowns were performed in duplicates with switched labellings. Specific interactors were destinguished from the background on the basis of SILAC Heavy to Light ratios between GST-RHOA and GST alone pulldowns.
2016-11-01 | PXD004934 | Pride
Project description:FoxM1 activates genes that regulate S-G2-M cell-cycle progression and, when overexpressed, is associated with poor clinical outcome in multiple cancers. Here we identify FoxM1 as a tumor suppressor in mice that, through its N-terminal domain, binds to and inhibits Ect2 to limit the activity of RhoA GTPase and its effector mDia1, a catalyst of cortical actin nucleation. FoxM1 insufficiency impedes centrosome movement through excessive cortical actin polymerization, thereby causing the formation of non-perpendicular mitotic spindles that missegregate chromosomes and drive tumorigenesis in mice. Importantly, low FOXM1 expression correlates with RhoA GTPase hyperactivity in multiple human cancer types, indicating that suppression of the newly discovered Ect2-RhoA-mDia1 oncogenic axis by FoxM1 is clinically relevant. Furthermore, by dissecting the domain requirements through which FoxM1 inhibits Ect2 GEF activity, we provide mechanistic insight for the development of pharmacological approaches that target protumorigenic RhoA activity.
2020-07-09 | GSE130410 | GEO
Project description:Rho-kinase signaling and YAP signaling are related to aortic dissection (AD) formation. However, as important biomechanical signaling pathways, their relationships with aortic smooth muscle cell (AoSMC) mechanics have not been investigated in AD formation. This study aims to explore the correlation between RhoA/ROCK1 and YAP, as well as their relationship with intrinsic AoSMC stiffness during AD formation. The expression of RhoA/ROCK1 and YAP as well as F-actin polymerization were analyzed in AoSMCs isolated from normal and AD human aortas. The intrinsic cell stiffness of normal and AD AoSMCs was measured using atomic force microscopy (AFM). The correlations among RhoA/ROCK1, YAP, and intrinsic AoSMC stiffness were explored by manipulating the activity of RhoA and ROCK1, and YAP expression. Finally, the role of RhoA/ROCK1/YAP/F-actin and AoSMC stiffness during AD formation was studied in pharmaceutically induced AD mouse models.Compared to normal human AoSMCs, the expression of RhoA and ROCK1 was downregulated, while the phosphorylation of YAP was increased in AD human AoSMCs, coupled with impaired F-actin polymerization and decreased intrinsic cell stiffness. Pharmaceutical inhibition of RhoA or ROCK1 activities and depletion of YAP all led to impaired F-actin polymerization and decreased intrinsic AoSMC stiffness. Moreover, abnormal collagen deposition and impaired cell-ECM interactions were found when RhoA/ROCK1/YAP/F-actin signaling was inhibited in normal human AoSMCs. We further analyzed the normal human AoSMC treated by Y27632 or not using RNA sequencing to investigate the impact of RhoA/ROCK1/YAP/F-actin on AoSMCs. GO analysis showed that differentially expressed genes (DEGs) related to cAMP-mediated signaling, cytoskeleton organization, cell-matrix adhesion, and extracellular matrix (ECM) organization were affected when ROCK1 activity was inhibited by Y27632 in normal AoSMCs. KEGG analysis showed differences in PI3K-Akt signaling, focal adhesion, MAPK, actin cytoskeleton, and ECM-receptor interaction. Consistently, cAMP, actin cytoskeleton organization, and ECM structural constituents were all downregulated in AoSMCs treated with Y27632 according to GSEA. We also analyzed the downregulated genes in AoSMCs treated with Y27632. Results demonstrated that the downregulated genes were mainly related to the cell-ECM unit, PI3K, MAPK, focal adhesion, and cAMP signaling pathways.
2024-03-01 | GSE247088 | GEO