scholarly journals The Hippo pathway transcriptional co-activator YAP is involved in head regeneration and bud development in Hydra

2021 ◽  
Author(s):  
Manu Krishnan Unni ◽  
Puli Chandramouli Reddy ◽  
Sanjeev Galande
Keyword(s):  
Target Genes ◽  
Hippo Pathway ◽  
Early Response ◽  
Immunofluorescence Assay ◽  
The Body ◽  
Hippo Signaling ◽  
Fate Specification ◽  
The Hippo Pathway ◽  
Body Column ◽  
Head Regeneration

The Hippo signaling pathway has been shown to be involved in the regulation of cellular identity, cell/tissue size maintenance and mechanotransduction. The Hippo pathway consists of a kinase cascade which determines the nucleo-cytoplasmic localization of YAP in the cell. YAP is the effector protein in the Hippo pathway which acts as a transcriptional cofactor for TEAD. Phosphorylation of YAP upon activation of the Hippo pathway prevents it from entering the nucleus and hence abrogates its function in transcription of target genes. In Cnidaria, the information on the regulatory roles of the Hippo pathway is virtually lacking. Here, we report for the first time the existence of a complete set of Hippo pathway core components in Hydra. By studying their phylogeny and domain organization, we report evolutionary conservation of the components of the Hippo pathway. Protein modelling suggested conservation of YAP-TEAD interaction in Hydra. We also characterized the expression pattern of the homologs of yap, hippo, mob and sav in Hydra using whole mount RNA in situ hybridization and report their possible role in stem cell maintenance. Immunofluorescence assay revealed that Hvul_YAP expressing cells occur in clusters in the body column and are excluded in the terminally differentiated regions. The YAP expressing cells are recruited early during head regeneration and budding implicating the Hippo pathway in early response to injury or establishment of oral fate. These cells exhibit a non-clustered existence at the site of regeneration and budding, indicating the involvement of a new population of YAP expressing cells during oral fate specification. Collectively, we posit that the Hippo pathway is an important signaling system in Hydra, its components are ubiquitously expressed in the Hydra body column, and may play crucial role in Hydra oral fate specification.

scholarly journals Identification of Components of the Hippo Pathway in Hydra and Potential Role of YAP in Cell Division and Differentiation

2021 ◽  
Vol 12 ◽  
Author(s):  
Manu Unni ◽  
Puli Chandramouli Reddy ◽  
Mrinmoy Pal ◽  
Irit Sagi ◽  
Sanjeev Galande
Keyword(s):  
Target Genes ◽  
Hippo Pathway ◽  
Critical Role ◽  
Immunofluorescence Assay ◽  
The Body ◽  
Hippo Signaling ◽  
Proliferating Cells ◽  
The Hippo Pathway ◽  
Body Column

The Hippo signaling pathway has been shown to be involved in regulating cellular identity, cell/tissue size maintenance and mechanotransduction. The Hippo pathway consists of a kinase cascade which determines the nucleo-cytoplasmic localization of YAP in the cell. YAP is the effector protein in the Hippo pathway, which acts as a transcriptional cofactor for TEAD. Phosphorylation of YAP upon activation of the Hippo pathway prevents it from entering the nucleus and abrogates its function in the transcription of the target genes. In Cnidaria, the information on the regulatory roles of the Hippo pathway is virtually lacking. Here, we report the existence of a complete set of Hippo pathway core components in Hydra for the first time. By studying their phylogeny and domain organization, we report evolutionary conservation of the components of the Hippo pathway. Protein modelling suggested the conservation of YAP-TEAD interaction in Hydra. Further, we characterized the expression pattern of the homologs of yap, hippo, mob and sav in Hydra using whole-mount RNA in situ hybridization and report their possible role in stem cell maintenance. Immunofluorescence assay revealed that Hvul_YAP expressing cells occur in clusters in the body column and are excluded in the terminally differentiated regions. Actively proliferating cells marked by Ki67 exhibit YAP colocalization in their nuclei. Strikingly, a subset of these colocalized cells is actively recruited to the newly developing bud. Disruption of the YAP-TEAD interaction increased the budding rate indicating a critical role of YAP in regulating cell proliferation in Hydra. Collectively, we posit that the Hippo pathway is an essential signaling system in Hydra; its components are ubiquitously expressed in the Hydra body column and play a crucial role in Hydra tissue homeostasis.

scholarly journals Hippo and rassf1a Pathways: A Growing Affair

2012 ◽  
Vol 2012 ◽  
pp. 1-12 ◽  
Author(s):  
Francesca Fausti ◽  
Silvia Di Agostino ◽  
Andrea Sacconi ◽  
Sabrina Strano ◽  
Giovanni Blandino
Keyword(s):  
Developmental Biology ◽  
Tissue Regeneration ◽  
Target Genes ◽  
Hippo Pathway ◽  
Hippo Signaling ◽  
Transcriptional Coactivator ◽  
Pathway Activity ◽  
Kinase Cascade ◽  
The Hippo Pathway ◽  
The Impact

First discovered in Drosophila, the Hippo pathway regulates the size and shape of organ development. Its discovery and study have helped to address longstanding questions in developmental biology. Central to this pathway is a kinase cascade leading from the tumor suppressor Hippo (Mst1 and Mst2 in mammals) to the Yki protein (YAP and TAZ in mammals), a transcriptional coactivator of target genes involved in cell proliferation, survival, and apoptosis. A dysfunction of the Hippo pathway activity is frequently detected in human cancers. Recent studies have highlighted that the Hippo pathway may play an important role in tissue homoeostasis through the regulation of stem cells, cell differentiation, and tissue regeneration. Recently, the impact of RASSF proteins on Hippo signaling potentiating its proapoptotic activity has been addressed, thus, providing further evidence for Hippo's key role in mammalian tumorigenesis as well as other important diseases.

scholarly journals Usp10 Modulates the Hippo Pathway by Deubiquitinating and Stabilizing the Transcriptional Coactivator Yorkie

2019 ◽  
Vol 20 (23) ◽  
pp. 6013
Author(s):  
Yang Gao ◽  
Xiaoting Zhang ◽  
Lijuan Xiao ◽  
Chaojun Zhai ◽  
Tao Yi ◽  
...  
Keyword(s):  
Target Genes ◽  
Hippo Pathway ◽  
Size Control ◽  
Deubiquitinating Enzyme ◽  
Hippo Signaling ◽  
Evolutionarily Conserved ◽  
Specific Protease ◽  
Wing Discs ◽  
The Hippo Pathway

The Hippo signaling pathway is an evolutionarily conserved regulator that plays important roles in organ size control, homeostasis, and tumorigenesis. As the key effector of the Hippo pathway, Yorkie (Yki) binds to transcription factor Scalloped (Sd) and promotes the expression of target genes, leading to cell proliferation and inhibition of apoptosis. Thus, it is of great significance to understand the regulatory mechanism for Yki protein turnover. Here, we provide evidence that the deubiquitinating enzyme ubiquitin-specific protease 10 (Usp10) binds Yki to counteract Yki ubiquitination and stabilize Yki protein in Drosophila S2 cells. The results in Drosophila wing discs indicate that silence of Usp10 decreases the transcription of target genes of the Hippo pathway by reducing Yki protein. In vivo functional analysis ulteriorly showed that Usp10 upregulates the Yki activity in Drosophila eyes. These findings uncover Usp10 as a novel Hippo pathway modulator and provide a new insight into the regulation of Yki protein stability and activity.

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.

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 POSH regulates Hippo signaling through ubiquitin-mediated expanded degradation

2018 ◽  
Vol 115 (9) ◽  
pp. 2150-2155 ◽  
Author(s):  
Xianjue Ma ◽  
Xiaowei Guo ◽  
Helena E. Richardson ◽  
Tian Xu ◽  
Lei Xue
Keyword(s):  
Target Genes ◽  
Hippo Pathway ◽  
Physiological Role ◽  
Cell Renewal ◽  
Hippo Signaling ◽  
Hippo Signaling Pathway ◽  
Stem Cell Renewal ◽  
The Hippo Pathway ◽  
Precise Molecular Mechanism

The Hippo signaling pathway is a master regulator of organ growth, tissue homeostasis, and tumorigenesis. The activity of the Hippo pathway is controlled by various upstream components, including Expanded (Ex), but the precise molecular mechanism of how Ex is regulated remains poorly understood. Here we identify Plenty of SH3s (POSH), an E3 ubiquitin ligase, as a key component of Hippo signaling in Drosophila. POSH overexpression synergizes with loss of Kibra to induce overgrowth and up-regulation of Hippo pathway target genes. Furthermore, knockdown of POSH impedes dextran sulfate sodium-induced Yorkie-dependent intestinal stem cell renewal, suggesting a physiological role of POSH in modulating Hippo signaling. Mechanistically, POSH binds to the C-terminal of Ex and is essential for the Crumbs-induced ubiquitination and degradation of Ex. Our findings establish POSH as a crucial regulator that integrates the signal from the cell surface to negatively regulate Ex-mediated Hippo activation in Drosophila.

scholarly journals The ZO-1 protein Polychaetoid as an upstream regulator of the Hippo pathway in Drosophila

PLoS Genetics ◽  
2021 ◽  
Vol 17 (11) ◽  
pp. e1009894
Author(s):  
Qingliang Sang ◽  
Gang Wang ◽  
David B. Morton ◽  
Hui Wu ◽  
Baotong Xie
Keyword(s):  
Hippo Pathway ◽  
Hippo Signaling ◽  
Fate Specification ◽  
Upstream Regulator ◽  
Neuronal Fate ◽  
Zonula Occludens ◽  
Pathway Activation ◽  
Core Components ◽  
The Hippo Pathway ◽  
Neuronal Fate Specification

The generation of a diversity of photoreceptor (PR) subtypes with different spectral sensitivities is essential for color vision in animals. In the Drosophila eye, the Hippo pathway has been implicated in blue- and green-sensitive PR subtype fate specification. Specifically, Hippo pathway activation promotes green-sensitive PR fate at the expense of blue-sensitive PRs. Here, using a sensitized triple heterozygote-based genetic screening approach, we report the identification of the single Drosophila zonula occludens-1 (ZO-1) protein Polychaetoid (Pyd) as a new regulator of the Hippo pathway during the blue- and green-sensitive PR subtype binary fate choice. We demonstrate that Pyd acts upstream of the core components and the upstream regulator Pez in the Hippo pathway. Furthermore, We found that Pyd represses the activity of Su(dx), a E3 ligase that negatively regulates Pez and can physically interact with Pyd, during PR subtype fate specification. Together, our results identify a new mechanism underlying the Hippo signaling pathway in post-mitotic neuronal fate specification.

scholarly journals Increasing kinase domain proximity promotes MST2 autophosphorylation during Hippo signaling

2020 ◽  
Vol 295 (47) ◽  
pp. 16166-16179
Author(s):  
Thao Tran ◽  
Jaba Mitra ◽  
Taekjip Ha ◽  
Jennifer M. Kavran
Keyword(s):  
Single Molecule ◽  
Hippo Pathway ◽  
Signal Propagation ◽  
Kinase Domain ◽  
Specific Protein ◽  
Hippo Signaling ◽  
Membrane Recruitment ◽  
Chemically Induced Dimerization ◽  
The Hippo Pathway

The Hippo pathway plays an important role in developmental biology, mediating organ size by controlling cell proliferation through the activity of a core kinase cassette. Multiple upstream events activate the pathway, but how each controls this core kinase cassette is not fully understood. Activation of the core kinase cassette begins with phosphorylation of the kinase MST1/2 (also known as STK3/4). Here, using a combination of in vitro biochemistry and cell-based assays, including chemically induced dimerization and single-molecule pulldown, we revealed that increasing the proximity of adjacent kinase domains, rather than formation of a specific protein assembly, is sufficient to trigger autophosphorylation. We validate this mechanism in cells and demonstrate that multiple events associated with the active pathway, including SARAH domain–mediated homodimerization, membrane recruitment, and complex formation with the effector protein SAV1, each increase the kinase domain proximity and autophosphorylation of MST2. Together, our results reveal that multiple and distinct upstream signals each utilize the same common molecular mechanism to stimulate MST2 autophosphorylation. This mechanism is likely conserved among MST2 homologs. Our work also highlights potential differences in Hippo signal propagation between each activating event owing to differences in the dynamics and regulation of each protein ensemble that triggers MST2 autophosphorylation and possible redundancy in activation.

scholarly journals NPHP4, a cilia-associated protein, negatively regulates the Hippo pathway

2011 ◽  
Vol 193 (4) ◽  
pp. 633-642 ◽  
Author(s):  
Sandra Habbig ◽  
Malte P. Bartram ◽  
Roman U. Müller ◽  
Ricarda Schwarz ◽  
Nikolaos Andriopoulos ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Cellular Proliferation ◽  
Nuclear Translocation ◽  
Hippo Pathway ◽  
Negative Regulator ◽  
Hippo Signaling ◽  
Transcriptional Coactivator ◽  
Hippo Signaling Pathway ◽  
The Hippo Pathway ◽  
Potent Negative Regulator

The conserved Hippo signaling pathway regulates organ size in Drosophila melanogaster and mammals and has an essential role in tumor suppression and the control of cell proliferation. Recent studies identified activators of Hippo signaling, but antagonists of the pathway have remained largely elusive. In this paper, we show that NPHP4, a known cilia-associated protein that is mutated in the severe degenerative renal disease nephronophthisis, acts as a potent negative regulator of mammalian Hippo signaling. NPHP4 directly interacted with the kinase Lats1 and inhibited Lats1-mediated phosphorylation of the Yes-associated protein (YAP) and TAZ (transcriptional coactivator with PDZ-binding domain), leading to derepression of these protooncogenic transcriptional regulators. Moreover, NPHP4 induced release from 14-3-3 binding and nuclear translocation of YAP and TAZ, promoting TEA domain (TEAD)/TAZ/YAP-dependent transcriptional activity. Consistent with these data, knockdown of NPHP4 negatively affected cellular proliferation and TEAD/TAZ activity, essentially phenocopying loss of TAZ function. These data identify NPHP4 as a negative regulator of the Hippo pathway and suggest that NPHP4 regulates cell proliferation through its effects on Hippo signaling.

scholarly journals The Hippo Pathway: A Master Regulatory Network Important in Cancer

Cells ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1416
Author(s):  
Qiuping Liu ◽  
Xiaomeng Liu ◽  
Guanbin Song
Keyword(s):  
Metabolic Regulation ◽  
Human Cancer ◽  
Hippo Pathway ◽  
Tumor Development ◽  
Biological Significance ◽  
Cancer Development ◽  
Hippo Signaling ◽  
Complex Regulation ◽  
And Function ◽  
The Hippo Pathway

The Hippo pathway is pervasively activated and has been well recognized to play critical roles in human cancer. The deregulation of Hippo signaling involved in cancer development, progression, and resistance to cancer treatment have been confirmed in several human cancers. Its biological significance and deregulation in cancer have drawn increasing interest in the past few years. A fundamental understanding of the complexity of the Hippo pathway in cancer is crucial for improving future clinical interventions and therapy for cancers. In this review, we try to clarify the complex regulation and function of the Hippo signaling network in cancer development, including its role in signal transduction, metabolic regulation, and tumor development, as well as tumor therapies targeting the Hippo pathway.

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