scholarly journals p53 Transactivation Domain Mediates Binding and Phase Separation With poly-PR/GR

2021 ◽  
Author(s):  
Sinem Usluer ◽  
Emil Spreitzer ◽  
Benjamin Bourgeois ◽  
Tobias Madl
Keyword(s):  
Phase Separation ◽  
Molecular Mechanisms ◽  
Hydrophobic Interactions ◽  
P53 Protein ◽  
Chromatin Accessibility ◽  
Model Organisms ◽  
Transactivation Domain ◽  
Protein Levels ◽  
C9orf72 Gene

Abstract: The most common genetic cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) is the presence of poly-PR/GR dipeptide repeats which are encoded by the C9orf72 gene. Recently, it was shown that poly-PR/GR alters chromatin accessibility which results in stabilization and enhancement of transcriptional activity of the tumor suppressor p53 in several neurodegenerative disease models. Reduction of p53 protein levels in cell and model organisms protects against neurotoxicity of poly-PR, and partially protects against neurotoxicity of poly-GR. Here, we aimed to study the detailed molecular mechanisms how p53 contributes to poly-PR/GR mediated neurodegeneration. Using a combination of biophysical techniques such as nuclear magnetic resonance (NMR) spectroscopy, fluorescence polarization, turbidity assays and differential interference contrast (DIC) microscopy, we found that p53 physically interacts with poly-PR/GR and triggers liquid-liquid phase separation of p53. We identified p53 transactivation domain 2 (TAD2) as the main binding site for PR25/GR25 and show that binding of poly-PR/GR to p53 is mediated by a network of electrostatic and/or hydrophobic interactions. Our findings might help to understand the mechanistic role of p53 in poly-PR/GR - associated neurodegeneration.

scholarly journals p53 Transactivation Domain Mediates Binding and Phase Separation with Poly-PR/GR

2021 ◽  
Vol 22 (21) ◽  
pp. 11431
Author(s):  
Sinem Usluer ◽  
Emil Spreitzer ◽  
Benjamin Bourgeois ◽  
Tobias Madl
Keyword(s):  
Phase Separation ◽  
Molecular Mechanisms ◽  
Hydrophobic Interactions ◽  
P53 Protein ◽  
Chromatin Accessibility ◽  
Chromosome 9 ◽  
Model Organisms ◽  
Transactivation Domain ◽  
Reading Frame ◽  
Protein Levels

The most common genetic cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) is the presence of poly-PR/GR dipeptide repeats, which are encoded by the chromosome 9 open reading frame 72 (C9orf72) gene. Recently, it was shown that poly-PR/GR alters chromatin accessibility, which results in the stabilization and enhancement of transcriptional activity of the tumor suppressor p53 in several neurodegenerative disease models. A reduction in p53 protein levels protects against poly-PR and partially against poly-GR neurotoxicity in cells. Moreover, in model organisms, a reduction of p53 protein levels protects against neurotoxicity of poly-PR. Here, we aimed to study the detailed molecular mechanisms of how p53 contributes to poly-PR/GR-mediated neurodegeneration. Using a combination of biophysical techniques such as nuclear magnetic resonance (NMR) spectroscopy, fluorescence polarization, turbidity assays, and differential interference contrast (DIC) microscopy, we found that p53 physically interacts with poly-PR/GR and triggers liquid–liquid phase separation of p53. We identified the p53 transactivation domain 2 (TAD2) as the main binding site for PR25/GR25 and showed that binding of poly-PR/GR to p53 is mediated by a network of electrostatic and/or hydrophobic interactions. Our findings might help to understand the mechanistic role of p53 in poly-PR/GR-associated neurodegeneration.

scholarly journals BAG3 contributes to HGF-mediated cell proliferation, migration, and invasion via the Egr1 pathway in gastric cancer

2018 ◽  
Vol 105 (1) ◽  
pp. 63-75
Author(s):  
Jae Chang Lee ◽  
Sung Ae Koh ◽  
Kyung Hee Lee ◽  
Jae-Ryong Kim
Keyword(s):  
Gastric Cancer ◽  
Cell Proliferation ◽  
Cell Invasion ◽  
Molecular Mechanisms ◽  
Migration And Invasion ◽  
Human Gastric Cancer ◽  
Protein Levels ◽  
Dependent Pathway

Introduction: Bcl2-associated athanogene 3 (BAG3) is elevated in several types of cancers. However, the role of BAG3 in progression of gastric cancer is unknown. Therefore, the present study aims to find out the role of BAG3 in hepatocyte growth factor (HGF)–mediated tumor progression and the molecular mechanisms by which HGF regulates BAG3 expression. Methods: BAG3 mRNA and protein were measured using reverse transcription polymerase chain reaction and Western blot in the 2 human gastric cancer cell lines, NUGC3 and MKN28, treated with or without HGF. The effects of BAG3 knockdown on cell proliferation, cell invasion, and apoptosis were analyzed by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, the in vitro 2-chamber invasion assay, and flow cytometry in BAG3 short hairpin RNA (shRNA)–transfected cells and control cells. The signaling pathways involved in BAG3 that are regulated by HGF were analyzed. The chromatin immunoprecipitation assay was used to determine binding of Egr1 to the BAG3 promoter. Results: BAG3 mRNA and protein levels were increased following treatment with HGF. HGF-mediated BAG3 upregulation increased cell proliferation and cell invasion; however, it decreased apoptosis. HGF-mediated BAG3 upregulation is regulated by an ERK and Egr1-dependent pathway. BAG3 may have an important role in HGF-mediated cell proliferation and metastasis in gastric cancer through an ERK and Egr1-dependent pathway. Conclusion: This pathway may provide novel therapeutic targets and provide information for further identification of other targets of therapeutic significance in gastric cancer.

scholarly journals Nox4 Mediates RANKL-induced ER-Phagy and Osteoclastogenesis via Activating ROS/PERK/eIF-2α/ATF4 Pathway

2020 ◽  
Author(s):  
Jing Sun ◽  
wugui chen ◽  
Songtao Li ◽  
Sizhen Yang ◽  
Ying Zhang ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Bone Resorption ◽  
Signaling Pathway ◽  
Molecular Mechanisms ◽  
Nuclear Factor Κb ◽  
Protein Levels ◽  
Unfolded Protein ◽  
Regulatory Effects ◽  
Protein Response

Abstract Background: Receptor activator of nuclear factor-κB ligand (RANKL) has been found to induce osteoclastogenesis and bone resorption. However, the underlying molecular mechanisms remain unclear. Methods: Osteoclastogenesis was evaluated by number of TRAP-positive multinuclear (≥3) osteoclasts, bone resorption pits and expression levels of related genes. Autophagy activity were evaluated by LC3-II/LC3-I ratio, number of autophagic vacuoles and adenovirus-mRFP-GFP-tagged LC3 reporting system; Inhibitor chloroquine (CQ) was used to verified the role of autophagy in RANKL-induced osteoclastogenesis; Via downregulating Nox4 with inhibitor (DPI) and retrovirus-conveyed shRNA, we further explored the importance of Nox4 in RANKL-induced autophagy and osteoclastogenesis, as well as the regulatory effects of Nox4 on nonmitochondrial reactive oxygen species (ROS) and PERK/eIF-2α/ATF4 pathway. Intracellular ROS scavenger (NAC), mitochondrial-targeted antioxidant (MitoTEMPO) and inhibitor of PERK (GSK2606414) were also employed to investigate the role of ROS and PERK/eIF-2α/ATF4 pathway in RANKL-induced autophagy and osteoclastogenesis. Results: RANKL markedly increased autophagy, while CQ treatment caused reduction of RANKL-induced autophagy and osteoclastogenesis. Consistent with the increased autophagy, the protein levels of Nox4 were significantly increased, and Nox4 was selectively localized within the endoplasmic reticulum (ER) after RANKL stimulation. DPI and shRNA efficiently decreased the protein level and (or) activity of Nox4 in the ER and inhibited RANKL-induced autophagy and osteoclastogenesis. Mechanistically, we found that Nox4 regulates RANKL-induced autophagy activation and osteoclastogenesis by stimulating the production of nonmitochondrial ROS. Additionally, Nox4-derived nonmitochondrial ROS dramatically activate PERK/eIF-2α/ATF4, which is a critical unfolded protein response (UPR)-related signaling pathway during ER stress. Blocking the activation of the PERK/eIF-2α/ATF4 signaling pathway either by Nox4 shRNA, ROS antioxidant or PERK inhibitor (GSK2606414) treatment significantly inhibited endoplasmic reticulum autophagy (ER-phagy) during RANKL-induced osteoclastogenesis. Conclusions: Our findings provide new insights into the processes of RANKL-induced osteoclastogenesis and will help the development of new therapeutic strategies for osteoclastogenesis-related diseases.

scholarly journals Histology-dependent prognostic role of pERK and p53 protein levels in early-stage non-small cell lung cancer

Oncotarget ◽  
2018 ◽  
Vol 9 (28) ◽  
pp. 19945-19960 ◽  
Author(s):  
Álvaro Quintanal-Villalonga ◽  
Mariló Mediano ◽  
Irene Ferrer ◽  
Ricardo Meléndez ◽  
Andrés Carranza-Carranza ◽  
...  
Keyword(s):  
Lung Cancer ◽  
Small Cell Lung Cancer ◽  
Cell Lung Cancer ◽  
Early Stage ◽  
P53 Protein ◽  
Small Cell ◽  
Small Cell Lung ◽  
Prognostic Role ◽  
Protein Levels

scholarly journals The Role of Gut Microbiota in Aging and Aging Related Neurodegenerative Disorders: Insights from Drosophila Model

Life ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 855
Author(s):  
Yan Kong ◽  
Liyuan Wang ◽  
Baichun Jiang
Keyword(s):  
Gut Microbiota ◽  
Neurodegenerative Disorders ◽  
Molecular Mechanisms ◽  
Physiological Function ◽  
Time Dependent ◽  
Model Organisms ◽  
Gi Tract ◽  
Drosophila Model ◽  
Increased Susceptibility

Aging is characterized by a time dependent impairment of physiological function and increased susceptibility to death. It is the major risk factor for neurodegeneration. Neurodegenerative disorders including Alzheimer’s disease (AD) and Parkinson’s disease (PD) are the main causes of dementia in the old population. Gut microbiota is a community of microorganisms colonized in the gastrointestinal (GI) tract. The alteration of gut microbiota has been proved to be associated with aging and aging related neurodegeneration. Drosophila is a powerful tool to study microbiota-mediated physiological and pathological functions. Here, we summarize the recent advances using Drosophila as model organisms to clarify the molecular mechanisms and develop a therapeutic method targeting microbiota in aging and aging-related neurodegenerative disorders.

scholarly journals RIPK1-Associated Inborn Errors of Innate Immunity

2021 ◽  
Vol 12 ◽  
Author(s):  
Jiahui Zhang ◽  
Taijie Jin ◽  
Ivona Aksentijevich ◽  
Qing Zhou
Keyword(s):  
Immune Deficiency ◽  
Molecular Mechanisms ◽  
Clinical Manifestations ◽  
Physiological Role ◽  
Model Organisms ◽  
Loss Of Function ◽  
Inborn Errors ◽  
Post Translational Modifications ◽  
Cell Death Signaling

RIPK1 (receptor-interacting serine/threonine-protein kinase 1) is a key molecule for mediating apoptosis, necroptosis, and inflammatory pathways downstream of death receptors (DRs) and pattern recognition receptors (PRRs). RIPK1 functions are regulated by multiple post-translational modifications (PTMs), including ubiquitination, phosphorylation, and the caspase-8-mediated cleavage. Dysregulation of these modifications leads to an immune deficiency or a hyperinflammatory disease in humans. Over the last decades, numerous studies on the RIPK1 function in model organisms have provided insights into the molecular mechanisms of RIPK1 role in the maintenance of immune homeostasis. However, the physiological role of RIPK1 in the regulation of cell survival and cell death signaling in humans remained elusive. Recently, RIPK1 loss-of-function (LoF) mutations and cleavage-deficient mutations have been identified in humans. This review discusses the molecular pathogenesis of RIPK1-deficiency and cleavage-resistant RIPK1 induced autoinflammatory (CRIA) disorders and summarizes the clinical manifestations of respective diseases to help with the identification of new patients.

scholarly journals Micro-RNA 21 inhibition of SMAD7 enhances fibrogenesis via leptin-mediated NADPH oxidase in experimental and human nonalcoholic steatohepatitis

2015 ◽  
Vol 308 (4) ◽  
pp. G298-G312 ◽  
Author(s):  
Diptadip Dattaroy ◽  
Sahar Pourhoseini ◽  
Suvarthi Das ◽  
Firas Alhasson ◽  
Ratanesh Kumar Seth ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Nadph Oxidase ◽  
Nonalcoholic Steatohepatitis ◽  
Molecular Mechanisms ◽  
Transforming Growth Factor ◽  
Micro Rna ◽  
Protein Levels ◽  
Significant Research ◽  
Human Livers

Hepatic fibrosis in nonalcoholic steatohepatitis (NASH) is the common pathophysiological process resulting from chronic liver inflammation and oxidative stress. Although significant research has been carried out on the role of leptin-induced NADPH oxidase in fibrogenesis, the molecular mechanisms that connect the leptin-NADPH oxidase axis in upregulation of transforming growth factor (TGF)-β signaling have been unclear. We aimed to investigate the role of leptin-mediated upregulation of NADPH oxidase and its subsequent induction of micro-RNA 21 (miR21) in fibrogenesis. Human NASH livers and a high-fat (60% kcal) diet-fed chronic mouse model, where hepatotoxin bromodichloromethane was used to induce NASH, were used for this study. To prove the role of the leptin-NADPH oxidase-miR21 axis, mice deficient in genes for leptin, p47phox, and miR21 were used. Results showed that wild-type mice and human livers with NASH had increased oxidative stress, increased p47phox expression, augmented NF-κB activation, and increased miR21 levels. These mice and human livers showed increased TGF-β, SMAD2/3-SMAD4 colocalizations in the nucleus, increased immunoreactivity against Col1α, and α-SMA with a concomitant decrease in protein levels of SMAD7. Mice that were deficient in leptin or p47phox had decreased activated NF-κB and miR21 levels, suggesting the role of leptin and NADPH oxidase in inducing NF-κB-mediated miR21 expression. Further miR21 knockout mice had decreased colocalization events of SMAD2/3-SMAD4 in the nucleus, increased SMAD7 levels, and decreased fibrogenesis. Taken together, the studies show the novel role of leptin-NADPH oxidase induction of miR21 as a key regulator of TGF-β signaling and fibrogenesis in experimental and human NASH.

scholarly journals Longevity: epigenetic and biomolecular aspects

2015 ◽  
Vol 6 (2) ◽  
pp. 105-117 ◽  
Author(s):  
Giusi Taormina ◽  
Mario G. Mirisola
Keyword(s):  
Simple Model ◽  
Molecular Mechanisms ◽  
Model Organisms ◽  
Intermittent Fasting ◽  
Epigenetic Mechanisms ◽  
Long Term Effects ◽  
Dietary Interventions ◽  
Aging Theories

AbstractMany aging theories and their related molecular mechanisms have been proposed. Simple model organisms such as yeasts, worms, fruit flies and others have massively contributed to their clarification, and many genes and pathways have been associated with longevity regulation. Among them, insulin/IGF-1 plays a key and evolutionary conserved role. Interestingly, dietary interventions can modulate this pathway. Calorie restriction (CR), intermittent fasting, and protein and amino acid restriction prolong the lifespan of mammals by IGF-1 regulation. However, some recent findings support the hypothesis that the long-term effects of diet also involve epigenetic mechanisms. In this review, we describe the best characterized aging pathways and highlight the role of epigenetics in diet-mediated longevity.

scholarly journals Twist Modulates Human Trophoblastic Cell Invasion via Regulation of N-Cadherin

Endocrinology ◽  
2012 ◽  
Vol 153 (2) ◽  
pp. 925-936 ◽  
Author(s):  
York Hunt Ng ◽  
Hua Zhu ◽  
Peter C. K. Leung
Keyword(s):  
Cell Invasion ◽  
Small Interfering Rna ◽  
Molecular Mechanisms ◽  
Dependent Manner ◽  
Trophoblastic Cell ◽  
Protein Levels ◽  
Bewo Cells ◽  
Interfering Rna ◽  
Tgf Β1

The invasion of extravillous cytotrophoblasts (EVT) into the underlying maternal tissues and vasculature is a key step in human placentation. The molecular mechanisms involved in the development of the invasive phenotype of EVT include many that were first discovered for their role in cancer cell metastasis. Previous studies have demonstrated that N-cadherin and its regulatory transcription factor Twist play important roles in the onset and progression of cancers, but their roles in human trophoblastic cell invasion is not clear. The goal of the study was to examine the role of Twist and N-cadherin in human trophoblastic cell invasion. Twist and N-cadherin mRNA and protein levels were determined by RT-PCR and Western blotting in human placental tissues, highly invasive EVT, and poorly invasive JEG-3 and BeWo cells. Whether IL-1β and TGF-β1 regulate Twist mRNA and protein levels in the EVT was also examined. A small interfering RNA strategy was employed to determine the role of Twist and N-cadherin in HTR-8/SVneo cell invasion. Matrigel assays were used to assess cell invasion. Twist and N-cadherin were highly expressed in EVT but were poorly expressed in JEG-3 and BeWo cells. IL-1β and TGF-β1 differentially regulated Twist expression in EVT in a time- and concentration-dependent manner. Small interfering RNA specific for Twist decreased N-cadherin and reduced invasion of HTR-8/SVneo cells. Similarly, a reduction in N-cadherin decreased the invasive capacity of HTR-8/SVneo cells. Twist is an upstream regulator of N-cadherin-mediated invasion of human trophoblastic cells.

scholarly journals Hlx homeobox transcription factor negatively regulates interferon-γ production in monokine-activated natural killer cells

Blood ◽  
2006 ◽  
Vol 109 (6) ◽  
pp. 2481-2487 ◽  
Author(s):  
Brian Becknell ◽  
Tiffany L. Hughes ◽  
Aharon G. Freud ◽  
Bradley W. Blaser ◽  
Jianhua Yu ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Nk Cells ◽  
Natural Killer ◽  
Molecular Mechanisms ◽  
Interferon Γ ◽  
Tumor Surveillance ◽  
Protein Levels ◽  
Homeobox Transcription Factor ◽  
Ifn Γ

Abstract Natural killer (NK) cells contribute to host immunity, including tumor surveillance, through the production of interferon gamma (IFN-γ). Although there is some knowledge about molecular mechanisms that induce IFN-γ in NK cells, considerably less is known about the mechanisms that reduce its expression. Here, we investigate the role of the Hlx transcription factor in IFN-γ production by NK cells. Hlx expression is induced in monokine-activated NK cells, but with delayed kinetics compared to IFN-γ. Ectopic Hlx expression decreases IFN-γ synthesis in primary human NK cells and IFN-γ promoter activity in an NK-like cell line. Hlx protein levels inversely correlate with those of STAT4, a requisite factor for optimal IFN-γ transcription. Mechanistically, we provide evidence indicating that Hlx overexpression accelerates dephosphorylation and proteasome-dependent degradation of the active Y693-phosphorylated form of STAT4. Thus, Hlx expression in activated NK cells temporally controls and limits the monokine-induced production of IFN-γ, in part through the targeted depletion of STAT4.

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