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 The Hippo Pathway: Immunity and Cancer

Cancers ◽  
2018 ◽  
Vol 10 (4) ◽  
pp. 94 ◽  
Author(s):  
Zaid Taha ◽  
Helena Janse van Rensburg ◽  
Xiaolong Yang
Keyword(s):  
Immune Response ◽  
Immune Cells ◽  
Mammalian Cells ◽  
Immune Cell ◽  
Hippo Pathway ◽  
Tissue Homeostasis ◽  
Hippo Signaling ◽  
Core Components ◽  
The Hippo Pathway ◽  
Future Work

Since its discovery, the Hippo pathway has emerged as a central signaling network in mammalian cells. Canonical signaling through the Hippo pathway core components (MST1/2, LATS1/2, YAP and TAZ) is important for development and tissue homeostasis while aberrant signaling through the Hippo pathway has been implicated in multiple pathologies, including cancer. Recent studies have uncovered new roles for the Hippo pathway in immunology. In this review, we summarize the mechanisms by which Hippo signaling in pathogen-infected or neoplastic cells affects the activities of immune cells that respond to these threats. We further discuss how Hippo signaling functions as part of an immune response. Finally, we review how immune cell-intrinsic Hippo signaling modulates the development/function of leukocytes and propose directions for future work.

scholarly journals Mutations and Copy Number Abnormalities of Hippo Pathway Components in Human Cancers

2021 ◽  
Vol 9 ◽  
Author(s):  
Zhengjin He ◽  
Ruihan Li ◽  
Hai Jiang
Keyword(s):  
Cell Proliferation ◽  
Cancer Cells ◽  
Copy Number ◽  
Human Cancer ◽  
Hippo Pathway ◽  
Copy Number Variations ◽  
Tissue Homeostasis ◽  
Hippo Signaling ◽  
Core Components ◽  
The Hippo Pathway

The Hippo pathway is highly conserved from Drosophila to mammals. As a key regulator of cell proliferation, the Hippo pathway controls tissue homeostasis and has a major impact on tumorigenesis. The originally defined core components of the Hippo pathway in mammals include STK3/4, LATS1/2, YAP1/TAZ, TEAD, VGLL4, and NF2. However, for most of these genes, mutations and copy number variations are relatively uncommon in human cancer. Several other recently identified upstream and downstream regulators of Hippo signaling, including FAT1, SHANK2, Gq/11, and SWI/SNF complex, are more commonly dysregulated in human cancer at the genomic level. This review will discuss major genomic events in human cancer that enable cancer cells to escape the tumor-suppressive effects of Hippo signaling.

scholarly journals Yorkie-independent negative feedback couples Hippo pathway activation with Kibra degradation

2020 ◽  
Author(s):  
Sherzod A. Tokamov ◽  
Ting Su ◽  
Anne Ullyot ◽  
Richard G. Fehon
Keyword(s):  
Negative Feedback ◽  
Feedback Loop ◽  
Hippo Pathway ◽  
Tissue Growth ◽  
Hippo Signaling ◽  
Hippo Signaling Pathway ◽  
The Core ◽  
Pathway Activation ◽  
The Hippo Pathway ◽  
Transcriptional Output

AbstractThe Hippo signaling pathway regulates tissue growth in many animals. Multiple upstream components are known to promote Hippo pathway activity, but the organization of these different inputs, the degree of crosstalk between them, and whether they are regulated in a distinct manner is not well understood. Kibra activates the Hippo pathway by recruiting the core Hippo kinase cassette to the apical cortex. Here we show that the Hippo pathway downregulates Kibra levels independently of Yorkie-mediated transcriptional output. We find that the Hippo pathway promotes Kibra degradation via SCFSlimb-mediated ubiquitination, that this effect requires the core kinases Hippo and Warts, and that this mechanism functions independently of other upstream Hippo pathway activators including Crumbs and Expanded. Moreover, Kibra degradation appears patterned across tissue. We propose that Kibra degradation by the Hippo pathway serves as a negative feedback loop to tightly control Kibra-mediated Hippo pathway activation and ensure optimally scaled and patterned tissue growth.

scholarly journals Deubiquitinase YOD1 potentiates YAP/TAZ activities through enhancing ITCH stability

2017 ◽  
Vol 114 (18) ◽  
pp. 4691-4696 ◽  
Author(s):  
Youngeun Kim ◽  
Wantae Kim ◽  
Yonghee Song ◽  
Jeong-Rae Kim ◽  
Kyungjoo Cho ◽  
...  
Keyword(s):  
Liver Cancer ◽  
Hippo Pathway ◽  
Hippo Signaling ◽  
Dependent Manner ◽  
Subsequent Increase ◽  
Biological Responses ◽  
Expression Of Genes ◽  
Core Components ◽  
The Stability ◽  
The Hippo Pathway

Hippo signaling controls the expression of genes regulating cell proliferation and survival and organ size. The regulation of core components in the Hippo pathway by phosphorylation has been extensively investigated, but the roles of ubiquitination−deubiquitination processes are largely unknown. To identify deubiquitinase(s) that regulates Hippo signaling, we performed unbiased siRNA screening and found that YOD1 controls biological responses mediated by YAP/TAZ. Mechanistically, YOD1 deubiquitinates ITCH, an E3 ligase of LATS, and enhances the stability of ITCH, which leads to reduced levels of LATS and a subsequent increase in the YAP/TAZ level. Furthermore, we show that the miR-21-mediated regulation of YOD1 is responsible for the cell-density-dependent changes in YAP/TAZ levels. Using a transgenic mouse model, we demonstrate that the inducible expression of YOD1 enhances the proliferation of hepatocytes and leads to hepatomegaly in a YAP/TAZ-activity-dependent manner. Moreover, we find a strong correlation between YOD1 and YAP expression in liver cancer patients. Overall, our data strongly suggest that YOD1 is a regulator of the Hippo pathway and would be a therapeutic target to treat liver cancer.

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 Hippo Pathway in Regulating Drug Resistance of Glioblastoma

2021 ◽  
Vol 22 (24) ◽  
pp. 13431
Author(s):  
Giacomo Casati ◽  
Laura Giunti ◽  
Anna Lisa Iorio ◽  
Arianna Marturano ◽  
Luisa Galli ◽  
...  
Keyword(s):  
Hippo Pathway ◽  
Binding Motif ◽  
Hippo Signaling ◽  
Pathway Activation ◽  
Promising Target ◽  
Kinase Cascade ◽  
Tumor Immunosuppression ◽  
The Central Nervous System ◽  
Immunosuppressive Microenvironment ◽  
The Hippo Pathway

Glioblastoma (GBM) represents the most common and malignant tumor of the Central Nervous System (CNS), affecting both children and adults. GBM is one of the deadliest tumor types and it shows a strong multidrug resistance (MDR) and an immunosuppressive microenvironment which remain a great challenge to therapy. Due to the high recurrence of GBM after treatment, the understanding of the chemoresistance phenomenon and how to stimulate the antitumor immune response in this pathology is crucial. The deregulation of the Hippo pathway is involved in tumor genesis, chemoresistance and immunosuppressive nature of GBM. This pathway is an evolutionarily conserved signaling pathway with a kinase cascade core, which controls the translocation of YAP (Yes-Associated Protein)/TAZ (Transcriptional Co-activator with PDZ-binding Motif) into the nucleus, leading to regulation of organ size and growth. With this review, we want to highlight how chemoresistance and tumor immunosuppression work in GBM and how the Hippo pathway has a key role in them. We linger on the role of the Hippo pathway evaluating the effect of its de-regulation among different human cancers. Moreover, we consider how different pathways are cross-linked with the Hippo signaling in GBM genesis and the hypothetical mechanisms responsible for the Hippo pathway activation in GBM. Furthermore, we describe various drugs targeting the Hippo pathway. In conclusion, all the evidence described largely support a strong involvement of the Hippo pathway in gliomas progression, in the activation of chemoresistance mechanisms and in the development of an immunosuppressive microenvironment. Therefore, this pathway is a promising target for the treatment of high grade gliomas and in particular of GBM.

scholarly journals Spectrin regulates Hippo signaling by modulating cortical actomyosin activity

eLife ◽  
2015 ◽  
Vol 4 ◽  
Author(s):  
Hua Deng ◽  
Wei Wang ◽  
Jianzhong Yu ◽  
Yonggang Zheng ◽  
Yun Qing ◽  
...  
Keyword(s):  
Hippo Pathway ◽  
Myosin Ii ◽  
Tissue Growth ◽  
Hippo Signaling ◽  
Upstream Regulator ◽  
Kinase Cascade ◽  
Cytoskeletal Tension ◽  
Living Tissues ◽  
The Hippo Pathway ◽  
Upstream Regulators

The Hippo pathway controls tissue growth through a core kinase cascade that impinges on the transcription of growth-regulatory genes. Understanding how this pathway is regulated in development remains a major challenge. Recent studies suggested that Hippo signaling can be modulated by cytoskeletal tension through a Rok-myosin II pathway. How cytoskeletal tension is regulated or its relationship to the other known upstream regulators of the Hippo pathway remains poorly defined. In this study, we identify spectrin, a contractile protein at the cytoskeleton-membrane interface, as an upstream regulator of the Hippo signaling pathway. We show that, in contrast to canonical upstream regulators such as Crumbs, Kibra, Expanded, and Merlin, spectrin regulates Hippo signaling in a distinct way by modulating cortical actomyosin activity through non-muscle myosin II. These results uncover an essential mediator of Hippo signaling by cytoskeleton tension, providing a new entry point to dissecting how mechanical signals regulate Hippo signaling in living tissues.

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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