scholarly journals Angiomotin regulates budding and spread of Ebola virus

2020 ◽  
Vol 295 (25) ◽  
pp. 8596-8601
Author(s):  
Ziying Han ◽  
Gordon Ruthel ◽  
Shantoshini Dash ◽  
Corbett T. Berry ◽  
Bruce D. Freedman ◽  
...  
Keyword(s):  
Matrix Protein ◽  
Ebola Virus ◽  
Hippo Pathway ◽  
Adaptor Protein ◽  
Actin Dynamics ◽  
Hippo Signaling ◽  
Dependent Manner ◽  
Host Proteins ◽  
Ww Domain ◽  
Actin Organization

The Ebola virus (EBOV) VP40 matrix protein (eVP40) orchestrates assembly and budding of virions in part by hijacking select WW-domain–bearing host proteins via its PPxY late (L)-domain motif. Angiomotin (Amot) is a multifunctional PPxY-containing adaptor protein that regulates angiogenesis, actin dynamics, and cell migration/motility. Amot also regulates the Hippo signaling pathway via interactions with the WW-domain–containing Hippo effector protein Yes-associated protein (YAP). In this report, we demonstrate that endogenous Amot is crucial for positively regulating egress of eVP40 virus-like particles (VLPs) and for egress and spread of authentic EBOV. Mechanistically, we show that ectopic YAP expression inhibits eVP40 VLP egress and that Amot co-expression rescues budding of eVP40 VLPs in a dose-dependent and PPxY-dependent manner. Moreover, results obtained with confocal and total internal reflection fluorescence microscopy suggested that Amot's role in actin organization and dynamics also contributes to promoting eVP40-mediated egress. In summary, these findings reveal a functional and competitive interplay between virus and host proteins involving the multifunctional PPxY-containing adaptor Amot, which regulates both the Hippo pathway and actin dynamics. We propose that our results have wide-ranging implications for understanding the biology and pathology of EBOV infections.

scholarly journals Viruses go modular

2020 ◽  
Vol 295 (14) ◽  
pp. 4604-4616 ◽  
Author(s):  
Ariel Shepley-McTaggart ◽  
Hao Fan ◽  
Marius Sudol ◽  
Ronald N. Harty
Keyword(s):  
Hippo Pathway ◽  
Host Proteins ◽  
Dna Viruses ◽  
Ww Domain ◽  
Ww Domains ◽  
Host Interactions ◽  
New Class ◽  
Domain Interactions ◽  
Molecular Aspects ◽  
The Hippo Pathway

The WW domain is a modular protein structure that recognizes the proline-rich Pro-Pro-x-Tyr (PPxY) motif contained in specific target proteins. The compact modular nature of the WW domain makes it ideal for mediating interactions between proteins in complex networks and signaling pathways of the cell (e.g. the Hippo pathway). As a result, WW domains play key roles in a plethora of both normal and disease processes. Intriguingly, RNA and DNA viruses have evolved strategies to hijack cellular WW domain–containing proteins and thereby exploit the modular functions of these host proteins for various steps of the virus life cycle, including entry, replication, and egress. In this review, we summarize key findings in this rapidly expanding field, in which new virus-host interactions continue to be identified. Further unraveling of the molecular aspects of these crucial virus-host interactions will continue to enhance our fundamental understanding of the biology and pathogenesis of these viruses. We anticipate that additional insights into these interactions will help support strategies to develop a new class of small-molecule inhibitors of viral PPxY-host WW-domain interactions that could be used as antiviral therapeutics.

Impaired Sphingosine-1-Phosphate Synthesis Induces Preeclampsia by Deactivating Trophoblastic YAP (Yes-Associated Protein) Through S1PR2 (Sphingosine-1-Phosphate Receptor-2)-Induced Actin Polymerizations

Hypertension ◽  
2021 ◽  
Author(s):  
Jiujiang Liao ◽  
Yangxi Zheng ◽  
Mingyu Hu ◽  
Ping Xu ◽  
Li Lin ◽  
...  
Keyword(s):  
Actin Polymerization ◽  
Sphingosine Kinase ◽  
Actin Dynamics ◽  
Extravillous Trophoblast ◽  
Trophoblast Invasion ◽  
Hippo Signaling ◽  
Dependent Manner ◽  
Sphingosine Kinase 1 ◽  
Sphingosine 1 Phosphate

Incomplete spiral artery remodeling, caused by impaired extravillous trophoblast invasion, is a fundamental pathogenic process associated with malplacentation and the development of preeclampsia. Nevertheless, the mechanisms controlling this regulation of trophoblast invasion are largely unknown. We report that sphingosine-1-phosphate synthesis and expression is abundant in healthy trophoblast, whereas in pregnancies complicated by preeclampsia the placentae are associated with reduced sphingosine-1-phosphate and lower SPHK1 (sphingosine kinase 1) expression and activity. In vivo inhibition of sphingosine kinase 1 activity during placentation in pregnant mice led to decreased placental sphingosine-1-phosphate production and defective placentation, resulting in a preeclampsia phenotype. Moreover, sphingosine-1-phosphate increased HTR8/SVneo (immortalized trophoblast cells) cell invasion in a Hippo-signaling–dependent transcriptional coactivator YAP (Yes-associated protein) dependent manner, which is activated by S1PR2 (sphingosine-1-phosphate receptor-2) and downstream RhoA/ROCK induced actin polymerization. Mutation-based YAP-5SA demonstrated that sphingosine-1-phosphate activation of YAP could be either dependent or independent of Hippo signaling. Together, these findings suggest a novel pathogenic pathway of preeclampsia via disrupted sphingosine-1-phosphate metabolism and signaling-induced, interrupted actin dynamics and YAP deactivation; this may lead to potential novel intervention targets for the prevention and management of preeclampsia.

scholarly journals Nerfin-1 represses transcriptional output of Hippo signaling in cell competition

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Pengfei Guo ◽  
Chang-Hyun Lee ◽  
Huiyan Lei ◽  
Yonggang Zheng ◽  
Katiuska Daniela Pulgar Prieto ◽  
...  
Keyword(s):  
Dna Binding ◽  
Hippo Pathway ◽  
Ectopic Expression ◽  
Tissue Growth ◽  
Hippo Signaling ◽  
Dependent Manner ◽  
Cell Competition ◽  
Regulatory Mode ◽  
The Hippo Pathway ◽  
Transcriptional Output

The Hippo tumor suppressor pathway regulates tissue growth in Drosophila by restricting the activity of the transcriptional coactivator Yorkie (Yki), which normally complexes with the TEF/TEAD family DNA-binding transcription factor Scalloped (Sd) to drive the expression of growth-promoting genes. Given its pivotal role as a central hub in mediating the transcriptional output of Hippo signaling, there is great interest in understanding the molecular regulation of the Sd-Yki complex. In this study, we identify Nerfin-1 as a transcriptional repressor that antagonizes the activity of the Sd-Yki complex by binding to the TEA DNA-binding domain of Sd. Consistent with its biochemical function, ectopic expression of Nerfin-1 results in tissue undergrowth in an Sd-dependent manner. Conversely, loss of Nerfin-1 enhances the ability of winner cells to eliminate loser cells in multiple scenarios of cell competition. We further show that INSM1, the mammalian ortholog of Nerfin-1, plays a conserved role in repressing the activity of the TEAD-YAP complex. These findings reveal a novel regulatory mode converging on the transcriptional output of the Hippo pathway that may be exploited for modulating the YAP oncoprotein in cancer and regenerative medicine.

scholarly journals The TEA domain family transcription factor TEAD4 represses murine adipogenesis by recruiting the cofactors VGLL4 and CtBP2 into a transcriptional complex

2018 ◽  
Vol 293 (44) ◽  
pp. 17119-17134 ◽  
Author(s):  
Wenxiang Zhang ◽  
Jinjin Xu ◽  
Jinhui Li ◽  
Tong Guo ◽  
Dan Jiang ◽  
...  
Keyword(s):  
Transcription Factors ◽  
Ternary Complex ◽  
Early Stage ◽  
Hippo Pathway ◽  
Adaptor Protein ◽  
Peroxisome Proliferator ◽  
Hippo Signaling ◽  
Domain Family ◽  
Independent Manner ◽  
Peroxisome Proliferator Activated Receptor

The Hippo signaling pathway is known to play an important role in multiple physiological processes, including adipogenesis. However, whether the downstream components of the Hippo pathway are involved in adipogenesis remains unknown. Here we demonstrate that the TEA domain family (TEAD) transcription factors are essential for adipogenesis in murine 3T3-L1 preadipocytes. Knockdown of TEAD1–4 stimulated adipogenesis and increased the expression of adipocyte markers in these cells. Interestingly, we found that the TEAD4 knockdown–mediated adipogenesis proceeded in a Yes-associated protein (YAP)/TAZ (Wwtr1)–independent manner and that adipogenesis suppression in WT cells involved formation of a ternary complex comprising TEAD4 and the transcriptional cofactors C-terminal binding protein 2 (CtBP2) and vestigial-like family member 4 (VGLL4). VGLL4 acted as an adaptor protein that enhanced the interaction between TEAD4 and CtBP2, and this TEAD4–VGLL4–CtBP2 ternary complex dynamically existed at the early stage of adipogenesis. Finally, we verified that TEAD4 directly targets the promoters of major adipogenesis transcription factors such as peroxisome proliferator–activated receptor γ (PPARγ) and adiponectin, C1Q, and collagen domain–containing (Adipoq) during adipogenesis. These findings reveal critical insights into the role of the TEAD4–VGLL4–CtBP2 transcriptional repressor complex in suppression of adipogenesis in murine preadipocytes.

scholarly journals Ubiquitin Ligase WWP1 Interacts with Ebola Virus VP40 To Regulate Egress

2017 ◽  
Vol 91 (20) ◽  
Author(s):  
Ziying Han ◽  
Cari A. Sagum ◽  
Fumio Takizawa ◽  
Gordon Ruthel ◽  
Corbett T. Berry ◽  
...  
Keyword(s):  
Ubiquitin Ligase ◽  
Mammalian Cells ◽  
Matrix Protein ◽  
Ebola Virus ◽  
E3 Ubiquitin Ligase ◽  
Hemorrhagic Fever ◽  
Efficient Production ◽  
Ww Domain ◽  
Ww Domains ◽  
E3 Ligases

ABSTRACT Ebola virus (EBOV) is a member of the Filoviridae family and the cause of hemorrhagic fever outbreaks. The EBOV VP40 (eVP40) matrix protein is the main driving force for virion assembly and budding. Indeed, expression of eVP40 alone in mammalian cells results in the formation and budding of virus-like particles (VLPs) which mimic the budding process and morphology of authentic, infectious EBOV. To complete the budding process, eVP40 utilizes its PPXY L-domain motif to recruit a specific subset of host proteins containing one or more modular WW domains that then function to facilitate efficient production and release of eVP40 VLPs. In this report, we identified additional host WW-domain interactors by screening for potential interactions between mammalian proteins possessing one or more WW domains and WT or PPXY mutant peptides of eVP40. We identified the HECT family E3 ubiquitin ligase WWP1 and all four of its WW domains as strong interactors with the PPXY motif of eVP40. The eVP40-WWP1 interaction was confirmed by both peptide pulldown and coimmunoprecipitation assays, which also demonstrated that modular WW domain 1 of WWP1 was most critical for binding to eVP40. Importantly, the eVP40-WWP1 interaction was found to be biologically relevant for VLP budding since (i) small interfering RNA (siRNA) knockdown of endogenous WWP1 resulted in inhibition of eVP40 VLP egress, (ii) coexpression of WWP1 and eVP40 resulted in ubiquitination of eVP40 and a subsequent increase in eVP40 VLP egress, and (iii) an enzymatically inactive mutant of WWP1 (C890A) did not ubiquitinate eVP40 or enhance eVP40 VLP egress. Last, our data show that ubiquitination of eVP40 by WWP1 enhances egress of VLPs and concomitantly decreases cellular levels of higher-molecular-weight oligomers of eVP40. In sum, these findings contribute to our fundamental understanding of the functional interplay between host E3 ligases, ubiquitination, and regulation of EBOV VP40-mediated egress. IMPORTANCE Ebola virus (EBOV) is a high-priority, emerging human pathogen that can cause severe outbreaks of hemorrhagic fever with high mortality rates. As there are currently no approved vaccines or treatments for EBOV, a better understanding of the biology and functions of EBOV-host interactions that promote or inhibit viral budding is warranted. Here, we describe a physical and functional interaction between EBOV VP40 (eVP40) and WWP1, a host E3 ubiquitin ligase that ubiquitinates VP40 and regulates VLP egress. This viral PPXY-host WW domain-mediated interaction represents a potential new target for host-oriented inhibitors of EBOV egress.

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 Integration of Cell Attachment, Cytoskeletal Localization, and Signaling by Integrin-linked Kinase (ILK), CH-ILKBP, and the Tumor Suppressor PTEN

2003 ◽  
Vol 14 (12) ◽  
pp. 4813-4825 ◽  
Author(s):  
Sarah Attwell ◽  
Julia Mills ◽  
Armelle Troussard ◽  
Chuanyue Wu ◽  
Shoukat Dedhar
Keyword(s):  
Tumor Suppressor ◽  
Kinase Activity ◽  
Cell Attachment ◽  
Adaptor Protein ◽  
Pi3 Kinase ◽  
Dependent Manner ◽  
New Paradigm ◽  
Genetic Studies ◽  
Actin Organization ◽  
Integrin Linked Kinase

Cell attachment and the assembly of cytoskeletal and signaling complexes downstream of integrins are intimately linked and coordinated. Although many intracellular proteins have been implicated in these processes, a new paradigm is emerging from biochemical and genetic studies that implicates integrin-linked kinase (ILK) and its interacting proteins, such as CH-ILKBP (α-parvin), paxillin, and PINCH in coupling integrins to the actin cytoskeleton and signaling complexes. Genetic studies in Drosophila, Caenorhabditis elegans, and mice point to an essential role of ILK as an adaptor protein in mediating integrin-dependent cell attachment and cytoskeletal organization. Here we demonstrate, using several different approaches, that inhibiting ILK kinase activity, or expression, results in the inhibition of cell attachment, cell migration, F-actin organization, and the specific cytoskeletal localization of CH-ILKBP and paxillin in human cells. We also demonstrate that the kinase activity of ILK is elevated in the cytoskeletal fraction and that the interaction of CH-ILKBP with ILK within the cytoskeleton stimulates ILK activity and downstream signaling to PKB/Akt and GSK-3. Interestingly, the interaction of CH-ILKBP with ILK is regulated by the Pi3 kinase pathway, because inhibition of Pi3 kinase activity by pharmacological inhibitors, or by the tumor suppressor PTEN, inhibits this interaction as well as cell attachment and signaling. These data demonstrate that the kinase and adaptor properties of ILK function together, in a Pi3 kinase–dependent manner, to regulate integrin-mediated cell attachment and signal transduction.

scholarly journals Adhesion to fibronectin regulates Hippo signaling via the FAK–Src–PI3K pathway

2015 ◽  
Vol 210 (3) ◽  
pp. 503-515 ◽  
Author(s):  
Nam-Gyun Kim ◽  
Barry M. Gumbiner
Keyword(s):  
Hippo Pathway ◽  
Growth Factor Receptor ◽  
Pi3k Pathway ◽  
Negative Regulator ◽  
Nuclear Accumulation ◽  
Hippo Signaling ◽  
Dependent Manner ◽  
Large Tumor ◽  
Inhibition Of Proliferation ◽  
The Hippo Pathway

The Hippo pathway is involved in the regulation of contact inhibition of proliferation and responses to various physical and chemical stimuli. Recently, several upstream negative regulators of Hippo signaling, including epidermal growth factor receptor ligands and lysophosphatidic acid, have been identified. We show that fibronectin adhesion stimulation of focal adhesion kinase (FAK)-Src signaling is another upstream negative regulator of the Hippo pathway. Inhibition of FAK or Src in MCF-10A cells plated at low cell density prevented the activation of Yes-associated protein (YAP) in a large tumor suppressor homologue (Lats)–dependent manner. Attachment of serum-starved MCF-10A cells to fibronectin, but not poly-d-lysine or laminin, induced YAP nuclear accumulation via the FAK–Src–phosphatidylinositol 4,5-bisphosphate 3-kinase (PI3K) signaling pathway. Attenuation of FAK, Src, PI3K, or PDK1 activity blocked YAP nuclear accumulation stimulated by adhesion to fibronectin. This negative regulation of the Hippo pathway by fibronectin adhesion signaling can, at least in part, explain the effects of cell spreading on YAP nuclear localization and represents a Lats-dependent component of the response to cell adhesion.

scholarly journals Glucocorticoids induce osteonecrosis of the femoral head through the Hippo signaling pathway

2021 ◽  
Vol 16 (1) ◽  
pp. 1130-1140
Author(s):  
Yugang Li ◽  
Zechuan Xu ◽  
Shan Chang
Keyword(s):  
Femoral Head ◽  
Signaling Pathway ◽  
Adipogenic Differentiation ◽  
Hippo Pathway ◽  
Control Group ◽  
Hippo Signaling ◽  
Dependent Manner ◽  
Alizarin Red ◽  
Hippo Signaling Pathway ◽  
Normal Differentiation

Abstract Osteonecrosis of the femoral head (ONFH) induced by glucocorticoids (GCs) has been considered to be associated with the dysfunction of bone marrow mesenchymal stem cells (BMSCs). Studies have reported that GCs can regulate the normal differentiation of BMSCs. However, the exact mechanism of this regulation remains unclear. In this study, we used methylprednisolone (MPS) to induce BMSCs, and then found that the Hippo signaling pathway was upregulated in a dose-dependent manner compared to that in the control group. In addition, the osteogenic ability of BMSCs was decreased, as evaluated by Alizarin Red S staining analysis and alkaline phosphatase activity assays, accompanied by the downregulated expression of Runx2, osteopontin, and osteocalcin. Additionally, the adipogenic capacity of BMSCs under the MPS conditions was increased, as identified by Oil Red O staining with upregulated triglyceride and PPARγ expression. Moreover, suppression by knockdown of MST1 was found to attenuate the Hippo signaling pathway and adipogenic differentiation, while enhancing osteogenic differentiation. In conclusion, our findings revealed that the Hippo signaling pathway was involved in GC-ONFH by affecting the osteogenic and adipogenic differentiation capacities of BMSCs. Our study could provide a basis for further investigation of the specific function of the Hippo pathway in ONFH.

scholarly journals The Phosphoinositide Phosphatase Sjl2 Is Recruited to Cortical Actin Patches in the Control of Vesicle Formation and Fission during Endocytosis

2005 ◽  
Vol 25 (8) ◽  
pp. 2910-2923 ◽  
Author(s):  
Christopher J. Stefan ◽  
Steven M. Padilla ◽  
Anjon Audhya ◽  
Scott D. Emr
Keyword(s):  
Membrane Trafficking ◽  
Plasma Membranes ◽  
Adaptor Protein ◽  
Actin Dynamics ◽  
Vesicle Formation ◽  
Cortical Actin ◽  
Actin Organization ◽  
Actin Patch ◽  
Sites Of Action ◽  
Mutant Cells

ABSTRACT The Saccharomyces cerevisiae synaptojanin-like proteins (Sjl1, Sjl2, and Sjl3) are phosphoinositide (PI) phosphatases that regulate PI metabolism in the control of actin organization and membrane trafficking. However, the primary sites of action for each of the yeast synaptojanin-like proteins remain unclear. In this study, we show that Sjl2 is localized to cortical actin patches, sites of endocytosis. Cortical recruitment of Sjl2 requires the actin patch component Abp1. Consistent with this, the SH3 domain-containing protein Abp1 physically associates with Sjl2 through its proline-rich domain. Furthermore, abp1Δ mutations confer defects resembling loss of SJL2; sjl1Δ abp1Δ double-mutant cells exhibit invaginated plasma membranes and impaired endocytosis, findings similar to those for sjl1Δ sjl2Δ mutant cells. Thus, Abp1 acts as an adaptor protein in the localization or concentration of Sjl2 during late stages of endocytic vesicle formation. Overexpression of the Hip1-related protein Sla2 delayed the formation of extended plasma membrane invaginations in sjl2 ts cells, indicating that Sla2 may become limiting or misregulated in cells with impaired PI phosphatase activity. Consistent with this, the cortical actin patch protein Sla2 is mislocalized in sjl1Δ sjl2Δ mutant cells. Together, our studies suggest that PI metabolism by the synaptojanin-like proteins coordinately directs actin dynamics and membrane invagination, in part by regulation of Sla2.

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