scholarly journals The Hippo effector Yorkie activates transcription by interacting with a histone methyltransferase complex through Ncoa6

eLife ◽  
2014 ◽  
Vol 3 ◽  
Author(s):  
Yun Qing ◽  
Feng Yin ◽  
Wei Wang ◽  
Yonggang Zheng ◽  
Pengfei Guo ◽  
...  
Keyword(s):  
Transcriptional Activation ◽  
Target Gene ◽  
Target Genes ◽  
Chromatin Modification ◽  
Growth Control ◽  
Tissue Growth ◽  
Hippo Signaling ◽  
Nuclear Receptor Coactivator ◽  
Potential Link ◽  
A Subunit

The Hippo signaling pathway regulates tissue growth in Drosophila through the transcriptional coactivator Yorkie (Yki). How Yki activates target gene transcription is poorly understood. Here, we identify Nuclear receptor coactivator 6 (Ncoa6), a subunit of the Trithorax-related (Trr) histone H3 lysine 4 (H3K4) methyltransferase complex, as a Yki-binding protein. Like Yki, Ncoa6 and Trr are functionally required for Hippo-mediated growth control and target gene expression. Strikingly, artificial tethering of Ncoa6 to Sd is sufficient to promote tissue growth and Yki target expression even in the absence of Yki, underscoring the importance of Yki-mediated recruitment of Ncoa6 in transcriptional activation. Consistent with the established role for the Trr complex in histone methylation, we show that Yki, Ncoa6, and Trr are required for normal H3K4 methylation at Hippo target genes. These findings shed light on Yki-mediated transcriptional regulation and uncover a potential link between chromatin modification and tissue growth.

scholarly journals The miRNA bantam regulates growth and tumorigenesis by repressing the cell cycle regulator tribbles

2019 ◽  
Vol 2 (4) ◽  
pp. e201900381 ◽  
Author(s):  
Stephan U Gerlach ◽  
Moritz Sander ◽  
Shilin Song ◽  
Héctor Herranz
Keyword(s):  
Cell Cycle ◽  
Cell Proliferation ◽  
Target Genes ◽  
Hippo Pathway ◽  
Growth Control ◽  
Tissue Growth ◽  
Tumor Formation ◽  
Hippo Signaling ◽  
Cell Cycle Regulators ◽  
The Hippo Pathway

One of the fundamental issues in biology is understanding how organ size is controlled. Tissue growth has to be carefully regulated to generate well-functioning organs, and defects in growth control can result in tumor formation. The Hippo signaling pathway is a universal growth regulator and has been implicated in cancer. In Drosophila, the Hippo pathway acts through the miRNA bantam to regulate cell proliferation and apoptosis. Even though the bantam targets regulating apoptosis have been determined, the target genes controlling proliferation have not been identified thus far. In this study, we identify the gene tribbles as a direct bantam target gene. Tribbles limits cell proliferation by suppressing G2/M transition. We show that tribbles regulation by bantam is central in controlling tissue growth and tumorigenesis. We expand our study to other cell cycle regulators and show that deregulated G2/M transition can collaborate with oncogene activation driving tumor formation.

scholarly journals Quantitative relationships between SMAD dynamics and target gene activation kinetics in single live cells

2018 ◽  
Author(s):  
Onur Tidin ◽  
Elias T. Friman ◽  
Felix Naef ◽  
David M. Suter
Keyword(s):  
Transcriptional Activation ◽  
Target Gene ◽  
Target Genes ◽  
Nuclear Translocation ◽  
Gene Activation ◽  
Transcriptional Response ◽  
Tissue Growth ◽  
Live Cells ◽  
High Temporal Resolution ◽  
Transcriptional Responses

AbstractThe transduction of extracellular signals through signaling pathways that culminate in a transcriptional response is central to many biological processes. However, quantitative relationships between activities of signaling pathway components and transcriptional output of target genes remain poorly explored. Here we developed a dual bioluminescence imaging strategy allowing simultaneous monitoring of nuclear translocation of the SMAD4 and SMAD2 transcriptional activators upon TGF-β stimulation, and the transcriptional response of the endogenous connective tissue growth factor (ctgf) gene. Using cell lines allowing to vary exogenous SMAD4/2 expression levels, we performed quantitative measurements of the temporal profiles of SMAD4/2 translocation and ctgf transcription kinetics in hundreds of individual cells at high temporal resolution. We found that while nuclear translocation efficiency had little impact on initial ctgf transcriptional activation, high total cellular SMAD4 but not SMAD2 levels increased the probability of cells to exhibit a sustained ctgf transcriptional response. The approach we present here allows time-resolved single cell quantification of transcription factor dynamics and transcriptional responses and thereby sheds light on the quantitative relationship between SMADs and target gene responses.

scholarly journals Transcriptional Inhibitors Identified in a 160,000-Compound Small-Molecule DUX4 Viability Screen

2016 ◽  
Vol 21 (7) ◽  
pp. 680-688 ◽  
Author(s):  
Si Ho Choi ◽  
Darko Bosnakovski ◽  
Jessica M. Strasser ◽  
Erik A. Toso ◽  
Michael A. Walters ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Muscular Dystrophy ◽  
Transcriptional Activation ◽  
Target Gene ◽  
Target Genes ◽  
Facioscapulohumeral Muscular Dystrophy ◽  
Oxidative Stress Pathway ◽  
Nonspecific Effects ◽  
Stress Pathway ◽  
Mouse Myoblast

Facioscapulohumeral muscular dystrophy is a genetically dominant, currently untreatable muscular dystrophy. It is caused by mutations that enable expression of the normally silent DUX4 gene, which encodes a pathogenic transcription factor. A screen based on Tet-on DUX4-induced mouse myoblast death previously uncovered compounds from a 44,000-compound library that protect against DUX4 toxicity. Many of those compounds acted downstream of DUX4 in an oxidative stress pathway. Here, we extend this screen to an additional 160,000 compounds and, using greater stringency, identify a new set of DUX4-protective compounds. From 640 hits, we performed secondary screens, repurchased 46 of the most desirable, confirmed activity, and tested each for activity against other cell death–inducing insults. The majority of these compounds also protected against oxidative stress. Of the 100 repurchased compounds identified through both screens, only SHC40, 75, and 98 inhibited DUX4 target genes, but they also inhibited dox-mediated DUX4 expression. Using a target gene readout on the 640-compound hit set, we discovered three overlooked compounds, SHC351, 540, and 572, that inhibit DUX4 target gene upregulation without nonspecific effects on the Tet-on system. These novel inhibitors of DUX4 transcriptional activity may thus act on pathways or cofactors needed by DUX4 for transcriptional activation in these cells.

scholarly journals Human ortholog of Drosophila Melted impedes SMAD2 release from TGF-β receptor I to inhibit TGF-β signaling

2015 ◽  
Vol 112 (23) ◽  
pp. E3000-E3009 ◽  
Author(s):  
Premalatha Shathasivam ◽  
Alexandra Kollara ◽  
Maurice J. Ringuette ◽  
Carl Virtanen ◽  
Jeffrey L. Wrana ◽  
...  
Keyword(s):  
Target Genes ◽  
Tissue Growth ◽  
Nuclear Accumulation ◽  
Ovarian Cancer Cells ◽  
Hippo Signaling ◽  
Ph Domain ◽  
Mouse Development ◽  
Transcriptional Responses ◽  
Β Receptor ◽  
The Impact

Drosophila melted encodes a pleckstrin homology (PH) domain-containing protein that enables normal tissue growth, metabolism, and photoreceptor differentiation by modulating Forkhead box O (FOXO), target of rapamycin, and Hippo signaling pathways. Ventricular zone expressed PH domain-containing 1 (VEPH1) is the mammalian ortholog of melted, and although it exhibits tissue-restricted expression during mouse development and is potentially amplified in several human cancers, little is known of its function. Here we explore the impact of VEPH1 expression in ovarian cancer cells by gene-expression profiling. In cells with elevated VEPH1 expression, transcriptional programs associated with metabolism and FOXO and Hippo signaling were affected, analogous to what has been reported for Melted. We also observed altered regulation of multiple transforming growth factor-β (TGF-β) target genes. Global profiling revealed that elevated VEPH1 expression suppressed TGF-β–induced transcriptional responses. This inhibitory effect was verified on selected TGF-β target genes and by reporter gene assays in multiple cell lines. We further demonstrated that VEPH1 interacts with TGF-β receptor I (TβRI) and inhibits nuclear accumulation of activated Sma- and Mad-related protein 2 (SMAD2). We identified two TβRI-interacting regions (TIRs) with opposing effects on TGF-β signaling. TIR1, located at the N terminus, inhibits canonical TGF-β signaling and promotes SMAD2 retention at TβRI, similar to full-length VEPH1. In contrast, TIR2, located at the C-terminal region encompassing the PH domain, decreases SMAD2 retention at TβRI and enhances TGF-β signaling. Our studies indicate that VEPH1 inhibits TGF-β signaling by impeding the release of activated SMAD2 from TβRI and may modulate TGF-β signaling during development and cancer initiation or progression.

scholarly journals Peroxisome Proliferator-Activated Receptor γ Target Gene Encoding a Novel Angiopoietin-Related Protein Associated with Adipose Differentiation

2000 ◽  
Vol 20 (14) ◽  
pp. 5343-5349 ◽  
Author(s):  
J. Cliff Yoon ◽  
Troy W. Chickering ◽  
Evan D. Rosen ◽  
Barry Dussault ◽  
Yubin Qin ◽  
...  
Keyword(s):  
Transcriptional Activation ◽  
Time Course ◽  
Target Gene ◽  
Target Genes ◽  
Peroxisome Proliferator ◽  
Peroxisome Proliferator Activated Receptor ◽  
Isolation And Characterization ◽  
Adipose Differentiation ◽  
Novel Target

ABSTRACT The nuclear receptor peroxisome proliferator-activated receptor γ regulates adipose differentiation and systemic insulin signaling via ligand-dependent transcriptional activation of target genes. However, the identities of the biologically relevant target genes are largely unknown. Here we describe the isolation and characterization of a novel target gene induced by PPARγ ligands, termed PGAR (for PPARγ angiopoietin related), which encodes a novel member of the angiopoietin family of secreted proteins. The transcriptional induction of PGAR follows a rapid time course typical of immediate-early genes and occurs in the absence of protein synthesis. The expression of PGAR is predominantly localized to adipose tissues and placenta and is consistently elevated in genetic models of obesity. Hormone-dependent adipocyte differentiation coincides with a dramatic early induction of the PGAR transcript. Alterations in nutrition and leptin administration are found to modulate the PGAR expression in vivo. Taken together, these data suggest a possible role for PGAR in the regulation of systemic lipid metabolism or glucose homeostasis.

scholarly journals Phase separation of TAZ compartmentalizes the transcription machinery to promote gene expression

2019 ◽  
Author(s):  
Tiantian Wu ◽  
Yi Lu ◽  
Orit Gutman ◽  
Huasong Lu ◽  
Qiang Zhou ◽  
...  
Keyword(s):  
Gene Expression ◽  
Phase Separation ◽  
Transcriptional Activation ◽  
Target Gene ◽  
Coiled Coil ◽  
Separation Mechanism ◽  
Hippo Signaling ◽  
Transcriptional Responses ◽  
Coiled Coil Domain

AbstractTAZ promotes cell proliferation, development, and tumorigenesis by regulating target gene transcription. However, how TAZ orchestrates the transcriptional responses remains poorly defined. Here we demonstrate that TAZ forms nuclear condensates via liquid-liquid phase separation to compartmentalize its DNA binding co-factor TEAD4, the transcription co-activators BRD4 and MED1 and the transcription elongation factor CDK9 for activation of gene expression. TAZ, but not its paralog YAP, forms phase-separated droplets in vitro and liquid-like nuclear condensates in vivo, and this ability is negatively regulated by Hippo signaling via LATS-mediated phosphorylation and mediated by the coiled-coil domain. Deletion of the TAZ coiled-coil domain or substitution with the YAP coiled-coil domain does not affect the interaction of TAZ with its partners, but prevents its phase separation and more importantly, its ability to induce target gene expression. Thus, our study identifies a novel mechanism for the transcriptional activation by TAZ and demonstrates for the first time that pathway-specific transcription factors also engage the phase separation mechanism for efficient transcription activation.

scholarly journals Poly(rC)-Binding Protein 2 Regulates Hippo Signaling To Control Growth in Breast Epithelial Cells

2016 ◽  
Vol 36 (16) ◽  
pp. 2121-2131 ◽  
Author(s):  
Fengmin Li ◽  
Kimberly Z. Bullough ◽  
Ajay A. Vashisht ◽  
James A. Wohlschlegel ◽  
Caroline C. Philpott
Keyword(s):  
Epithelial Cells ◽  
Target Genes ◽  
Hippo Pathway ◽  
Control Cell ◽  
Tissue Growth ◽  
Hippo Signaling ◽  
Breast Epithelial Cells ◽  
Mouse Tissues ◽  
Kinase Cascade ◽  
Breast Epithelial

Poly(rC)-binding proteins (PCBPs) are multifunctional adapters that mediate interactions between nucleic acids, iron cofactors, and other proteins, affecting the fates and activities of the components of these interactions. Here, we show that PCBP2 forms a complex with the Hippo pathway components Salvador (Sav1), Mst1, Mst2, and Lats1 in human cells and mouse tissues. Hippo is a kinase cascade that functions to phosphorylate and inactivate the transcriptional coactivators YAP and TAZ, which control cell growth and proliferation. PCBP2 specifically interacts with the scaffold protein Sav1 and prevents proteolytic cleavage of the Mst1 kinase, resulting in increased signaling through Hippo and suppressed activity of YAP and TAZ. Human breast epithelial cells lacking PCBP2 exhibit impaired proteasomal degradation of TAZ. They accumulate TAZ in both the nucleus and the cytosol, increase expression of YAP and TAZ connective tissue growth factor (CTGF) and Cyr61 target genes, and exhibit anchorage-independent growth. Thus, PCBP2 can function as a component of the Hippo complex, enhancing signaling, suppressing activity of YAP and TAZ, and altering the growth characteristics of cells.

scholarly journals GAC63, a GRIP1-Dependent Nuclear Receptor Coactivator

2005 ◽  
Vol 25 (14) ◽  
pp. 5965-5972 ◽  
Author(s):  
Yong-Heng Chen ◽  
Jeong Hoon Kim ◽  
Michael R. Stallcup
Keyword(s):  
Estrogen Receptor ◽  
Protein Interactions ◽  
Transcriptional Activation ◽  
Target Genes ◽  
Gene Promoter ◽  
Dependent Manner ◽  
Protein Protein Interactions ◽  
Promoter Regions ◽  
Nuclear Receptor Coactivator ◽  
Binding Domains

ABSTRACT Nuclear receptors (NRs) regulate target gene transcription through the recruitment of multiple coactivator complexes to the promoter regions of target genes. One important coactivator complex includes a p160 coactivator (GRIP1, SRC-1, or ACTR) and its downstream coactivators (e.g., p300, CARM1, CoCoA, and Fli-I), which contribute to transcriptional activation by protein acetylation, protein methylation, and protein-protein interactions. In this study, we identified a novel NR coactivator, GAC63, which binds to the N-terminal region of p160 coactivators as well as the ligand binding domains of some NRs. GAC63 enhanced transcriptional activation by NRs in a hormone-dependent and GRIP1-dependent manner in transient transfection assays and cooperated synergistically and selectively with other NR coactivators, including GRIP1 and CARM1, to enhance estrogen receptor function. Endogenous GAC63 was recruited to the estrogen-responsive pS2 gene promoter of MCF-7 cells in response to the hormone. Reduction of the endogenous GAC63 level by small interfering RNA inhibited transcriptional activation by the hormone-activated estrogen receptor. Thus, GAC63 is a physiologically relevant part of the p160 coactivator signaling pathway that mediates transcriptional activation by NRs.

scholarly journals Liver X Receptor Ligands Suppress Ubiquitination and Degradation of LXRα by Displacing BARD1/BRCA1

2009 ◽  
Vol 23 (4) ◽  
pp. 466-474 ◽  
Author(s):  
Kang Ho Kim ◽  
Jeong Min Yoon ◽  
A Hyun Choi ◽  
Woo Sik Kim ◽  
Gha Young Lee ◽  
...  
Keyword(s):  
Transcriptional Activation ◽  
Target Gene ◽  
Target Genes ◽  
Cancer Susceptibility ◽  
Liver X Receptor ◽  
Lipid Homeostasis ◽  
Gene Promoters ◽  
Receptor Ligands ◽  
Ubiquitin E3 Ligase ◽  
Ligand Free

Abstract Liver X receptor (LXR) is a ligand-activated transcription factor that plays important roles in cholesterol and lipid homeostasis. However, ligand-induced posttranslational modification of LXR is largely unknown. Here, we show that ligand-free LXRα is rapidly degraded by ubiquitination. Without ligand, LXRα interacts with an ubiquitin E3-ligase protein complex containing breast and ovarian cancer susceptibility 1 (BRCA1)-associated RING domain 1 (BARD1). Interestingly, LXR ligand represses ubiquitination and degradation of LXRα, and the interaction between LXRα and BARD1 is inhibited by LXR ligand. Consistently, T0901317, a synthetic LXR ligand, increased the level of LXRα protein in liver. Moreover, overexpression of BARD1/BRCA1 promoted the ubiquitination of LXRα and reduced the recruitment of LXRα to the target gene promoters, whereas BARD1 knockdown reversed such effects. Taken together, these data suggest that LXR ligand prevents LXRα from ubiquitination and degradation by detaching BARD1/BRCA1, which might be critical for the early step of transcriptional activation of ligand-stimulated LXRα through a stable binding of LXRα to the promoters of target genes.

scholarly journals The Hippo pathway component Wwc2 is a key regulator of embryonic development and angiogenesis in mice

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Anke Hermann ◽  
Guangming Wu ◽  
Pavel I. Nedvetsky ◽  
Viktoria C. Brücher ◽  
Charlotte Egbring ◽  
...  
Keyword(s):  
Embryonic Development ◽  
Cell Fate ◽  
Target Genes ◽  
Hippo Pathway ◽  
Growth Control ◽  
Binding Motif ◽  
Hippo Signaling ◽  
Large Tumor ◽  
Organ Growth ◽  
The Hippo Pathway

AbstractThe WW-and-C2-domain-containing (WWC) protein family is involved in the regulation of cell differentiation, cell proliferation, and organ growth control. As upstream components of the Hippo signaling pathway, WWC proteins activate the Large tumor suppressor (LATS) kinase that in turn phosphorylates Yes-associated protein (YAP) and its paralog Transcriptional coactivator-with-PDZ-binding motif (TAZ) preventing their nuclear import and transcriptional activity. Inhibition of WWC expression leads to downregulation of the Hippo pathway, increased expression of YAP/TAZ target genes and enhanced organ growth. In mice, a ubiquitous Wwc1 knockout (KO) induces a mild neurological phenotype with no impact on embryogenesis or organ growth. In contrast, we could show here that ubiquitous deletion of Wwc2 in mice leads to early embryonic lethality. Wwc2 KO embryos display growth retardation, a disturbed placenta development, impaired vascularization, and finally embryonic death. A whole-transcriptome analysis of embryos lacking Wwc2 revealed a massive deregulation of gene expression with impact on cell fate determination, cell metabolism, and angiogenesis. Consequently, a perinatal, endothelial-specific Wwc2 KO in mice led to disturbed vessel formation and vascular hypersprouting in the retina. In summary, our data elucidate a novel role for Wwc2 as a key regulator in early embryonic development and sprouting angiogenesis in mice.

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