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A novel GSK3β inhibitor ameliorates tau aggregation and neuroinflammation in Alzheimer's disease.

In Alzheimer's disease, increased GSK3β activity drives tau phosphorylation and directly or indirectly triggers neuroinflammation, neuronal damage and cognitive decline. We previously developed a novel GSK3β inhibitor, ZLWH-60, which demonstrated inhibitory activity with an IC50 of 11.5 nM. Here, we comprehensively evaluated the therapeutic potential of ZLWH-60 in suppressing tau pathology and neuroinflammation using multiple chemically-induced AD models. Our results demonstrate that ZLWH-60 could reduce the phosphorylation of multiple tau epitopes by inhibiting the activity of GSK3β, thereby …

Recycling of ribosomes at stop codons drives the rate of translation and the transition from proliferation to RESt.

Translation is made of initiation, elongation, and termination. The role of termination in relaying extracellular outputs to the translation machinery is unknown. We show, in mice, that the controlled recycling of ribosomes post-termination is a major checkpoint that integrates mitogenic signals and antiviral responses. In detail, the recycling of ribosomes at stop codons, maximal translation, and cellular proliferation strictly depend on eIF6 phosphorylation, both in vitro and in vivo. Lack of eIF6 phosphorylation, as observed during viral infection or prolonged starving, causes accumulation …

Characterization of the Signaling Pathways Activated by KCl-Induced RTK Stimulation in Guinea Pig Airways.

We found that, in guinea pig airway smooth muscle, the pharmacological inhibition of RTKs significantly decreased the contraction induced by 20 mM KCl. We observed that MEK pharmacological inhibitors diminished the contraction induced by 20 mM KCl, but not that induced by 60 mM. On the other hand, ERK inhibitors also altered the contraction generated by 20 mM KCl. When a ROCK inhibitor was tested, we found that it significantly inhibited the KCl-induced contraction. These results were complemented with Western blot experiments, and a decrease in ERK phosphorylation was noticed when the RTKs we…

Diet-metabolism-transcription axis modulates the sensitivity to CDK4/6 inhibitors through RB1 in prostate cancer.

A high-fat diet (HFD) promotes tumor progression and therapeutic resistance, but its mechanistic role in prostate cancer (PCa) remains unclear. In this study, we show that an HFD not only accelerates PCa progression but also significantly reduces sensitivity to CDK4/6 inhibitors. Mechanistically, an HFD activates CDK4, inducing RB1 phosphorylation and facilitating E2F1 release. Meanwhile, phosphorylation of RB1 at the S249/T252 site enhances its interaction with ETS1 and suppresses ETS1's transcriptional activity. Treatment with CDK4/6 inhibitors induces dephosphorylation at this site, relievi…

IGFBP6 orchestrates antiinfective immune collapse in murine sepsis via prohibitin-2-mediated immunosuppression.

The persistent challenge of sepsis-related mortality underscores the necessity for deeper insights. Our multicenter, cross-age cohort study identified insulin-like growth factor binding protein 6 (IGFBP6) as a critical regulator in sepsis diagnosis, prognosis, and mortality risk evaluation. Mechanistically, IGFBP6 engages in IGF-independent binding to prohibitin2 (PHB2) on epithelial cells, driving PHB2 tyrosine phosphorylation during sepsis. This process disrupts STAT1 phosphorylation, nuclear translocation, and its recruitment to the CCL2 promoter, ultimately impairing CCL2 transcription and…

Decoding spliceosome inhibition: Isobaric tag-based proteomic profiling of pladienolide B treated human cell lines.

Pladienolide B (Pla-B) is a potent splicing modulator that has shown promise in cancer treatment, but its cellular effects remain incompletely understood. We investigated the dose-associated effect of Pla-B on human cell lines using isobaric tag-based quantitative proteomics and phosphoproteomics techniques. We quantified over 10,000 proteins and 19,000 phosphorylation events in SH-SY5Y cells, revealing dose-associated changes in protein abundance and phosphorylation status. Low Pla-B concentrations induced significant alterations in nuclear proteins, specifically those involved in transcripti…

GRK2 kinases in the primary cilium initiate SMOOTHENED-PKA signaling in the Hedgehog cascade.

During Hedgehog (Hh) signal transduction in development and disease, the atypical G protein-coupled receptor (GPCR) SMOOTHENED (SMO) communicates with GLI transcription factors by binding the protein kinase A catalytic subunit (PKA-C) and physically blocking its enzymatic activity. Here, we show that GPCR kinase 2 (GRK2) orchestrates this process during endogenous mouse and zebrafish Hh pathway activation in the primary cilium. Upon SMO activation, GRK2 rapidly relocalizes from the ciliary base to the shaft, triggering SMO phosphorylation and PKA-C interaction. Reconstitution studies reveal th…

The expression of keratan sulfate in malignant melanoma enhances the adhesion and invasion activity of melanoma cells.

Mammals express a wide variety of glycans that include N-glycans, O-glycans, proteoglycans, glycolipids, etc. Glycan expression can modulate the cellular functions, and hence is strongly involved in the onset and progression of numerous diseases. Here, we report the relevance of the ectopic expression of keratan sulfate (KS) glycan chains in human malignant melanomas. Using a human melanoma cell line, we found that the KS enhanced the invasiveness of the cells but caused no change in the growth rate of the cells. The phosphorylation of paxillin, a focal adhesion-associated adaptor protein, was…

Mammalian D-cysteine: A novel regulator of neural progenitor cell proliferation Mammalian D-cysteine: A novel regulator of neural progenitor cell proliferation Endogenous D-cysteine, the stereoisomer with rapid spontaneous in vitro racemization rate, has major neural roles.

D-amino acids are being recognized as functionally important molecules in mammals. We recently identified endogenous D-cysteine in mammalian brain. D-cysteine is present in neonatal brain in substantial amounts (mM) and decreases with postnatal development. D-cysteine binds to MARCKS and a host of proteins implicated in cell division and neurodevelopmental disorders. D-cysteine decreases phosphorylation of MARCKS in neural progenitor cells (NPCs) affecting its translocation. D-cysteine controls NPC proliferation by inhibiting AKT signaling. Exogenous D-cysteine inhibits AKT phosphorylation at …

PPM1D suppresses p53-dependent transactivation and cell death by inhibiting the Integrated Stress Response.

The p53 transcription factor is a master regulator of cellular stress responses inhibited by repressors such as MDM2 and the phosphatase PPM1D. Activation of p53 with pharmacological inhibitors of its repressors is being tested in clinical trials for cancer therapy, but efficacy has been limited by poor induction of tumor cell death. We demonstrate that dual inhibition of MDM2 and PPM1D induces apoptosis in multiple cancer cell types via amplification of the p53 transcriptional program through the eIF2α-ATF4 pathway. PPM1D inhibition induces phosphorylation of eIF2α, ATF4 accumulation, and ATF…

Biased M1-muscarinic-receptor-mutant mice inform the design of next-generation drugs.

Cholinesterase inhibitors, the current frontline symptomatic treatment for Alzheimer's disease (AD), are associated with low efficacy and adverse effects. M1 muscarinic acetylcholine receptors (M1 mAChRs) represent a potential alternate therapeutic target; however, drug discovery programs focused on this G protein-coupled receptor (GPCR) have failed, largely due to cholinergic adverse responses. Employing novel chemogenetic and phosphorylation-deficient, G protein-biased, mouse models, paired with a toolbox of probe molecules, we establish previously unappreciated pharmacologically targetable …

Vascular permeability in retinopathy is regulated by VEGFR2 Y949 signaling to VE-cadherin.

Edema stemming from leaky blood vessels is common in eye diseases such as age-related macular degeneration and diabetic retinopathy. Whereas … rating regulation of permeability from angiogenesis. Strikingly, vascular endothelial (VE)-cadherin phosphorylation at the Y685, but not Y658, residue is reduced when VEGFR2 pY949 signaling is impaired. These findings support a mechanism whereby VE-cadherin Y685 phosphorylation is selectively associated with excessive vascular leakage. Therapeutically, targeting …

Phosphoproteomics of Acute Cell Stressors Targeting Exercise Signaling Networks Reveal Drug Interactions Regulating Protein Secretion.

Exercise engages signaling networks to control the release of circulating factors beneficial to health. However, the nature of these networks remains undefined. Using high-throughput phosphoproteomics, we quantify 20,249 phosphorylation sites in skeletal muscle-like myotube cells and monitor their responses to a panel of cell stressors targeting aspects of exercise signaling in vivo. Integrating these in-depth phosphoproteomes with the phosphoproteome of acute aerobic exercise in human skeletal muscle suggests that co-administration of β-adrenergic and calcium agonists would activate complemen…

Protein phosphatase 1 regulates huntingtin exon 1 aggregation and toxicity.

Huntington's disease is neurodegenerative disorder caused by a polyglutamine expansion in the N-terminal region of the huntingtin protein (N17). Here, we analysed the relative contribution of each phosphorylatable residue in the N17 region (T3, S13 and S16) towards huntingtin exon 1 (HTTex1) oligomerization, aggregation and toxicity in human cells and Drosophila neurons. We used bimolecular fluorescence complementation to show that expression of single phosphomimic mutations completely abolished HTTex1 aggregation in human cells. In Drosophila, mimicking phosphorylation at T3 decreased HTTex1 …

Genetic defects in PI3Kδ affect B-cell differentiation and maturation leading to hypogammaglobulineamia and recurrent infections.

BACKGROUND: Mutations in PIK3CD and PIK3R1 cause activated PI3K-δ syndrome (APDS) by dysregulation of the PI3K-AKT pathway. METHODS: We studied precursor and peripheral B-cell differentiation and apoptosis via flowcytometry. Furthermore, we performed AKT-phosphorylation assays and somatic hypermutations (SHM) and class switch recombination (CSR) analysis. RESULTS: We identified 13 patients of whom 3 had new mutations in PIK3CD or PIK3R1. Patients had low total B-cell numbers with increased frequencies of transitional B cells and plasmablasts, while the precursor B-cell compartment in bone ma…

PKM2 dephosphorylation by Cdc25A promotes the Warburg effect and tumorigenesis.

Many types of human tumour cells overexpress the dual-specificity phosphatase Cdc25A. Cdc25A dephosphorylates cyclin-dependent kinase and regulates the cell cycle, but other substrates of Cdc25A and their relevant cellular functions have yet to be identified. We demonstrate here that EGFR activation results in c-Src-mediated Cdc25A phosphorylation at Y59, which interacts with nuclear pyruvate kinase M2 (PKM2). Cdc25A dephosphorylates PKM2 at S37, and promotes PKM2-dependent β-catenin transactivation and c-Myc-upregulated expression of the glycolytic genes GLUT1, PKM2 and LDHA, and of CDC25A; t…

Dicer functions as an antiviral system against human adenoviruses via cleavage of adenovirus-encoded noncoding RNA.

In various organisms, including nematodes and plants, RNA interference (RNAi) is a defense system against virus infection; however, it is unclear whether RNAi functions as an antivirus system in mammalian cells. Rather, a number of DNA viruses, including herpesviruses, utilize post-transcriptional silencing systems for their survival. Here we show that Dicer efficiently suppresses the replication of adenovirus (Ad) via cleavage of Ad-encoding small RNAs (VA-RNAs), which efficiently promote Ad replication via the inhibition of eIF2α phosphorylation, to viral microRNAs (mivaRNAs). The Dicer knoc…

Mechanism of action of a WWTR1(TAZ)-CAMTA1 fusion oncoprotein.

The WWTR1 (protein is known as TAZ)-CAMTA1 (WC) fusion gene defines epithelioid hemangioendothelioma, a malignant vascular cancer. TAZ (transcriptional coactivator with PDZ binding motif) is a transcriptional coactivator and end effector of the Hippo tumor suppressor pathway. It is inhibited by phosphorylation by the Hippo kinases LATS1 and LATS2. Such phosphorylation causes cytoplasmic localization, 14-3-3 protein binding and the phorphorylation of a terminal phosphodegron promotes ubiquitin-dependent degradation (the phosphorylation of the different motifs has several effects). CAMTA1 is a p…

Вирус лихорадки Рифт-Вэлли NS сдерживает транскрипцию хостинга независимо от деградации белковой киназы PKR, зависящей от DSRNA.

Вирус лихорадки Рифт-Вэлли (RVFV) кодирует один из основных факторов вирулентности — протеин NS. NS подавляет общую транскрипцию, включая интерферон (IFN)-β mRNA синтез, и поощряет деградацию зависимости от белковой киназы (PKR) dsRNA. Мы создали новый мутант RVFV (rMP12-NSSR173A), конкретно не выполняющий функции по содействию деградации PKR. rMP12-NSSR173A вызывает раннюю фосфорилизацию eIF2α в результате активации PKR, сохраняя при этом функцию, направленную на сдерживание общей транскрипции, включая ингибицию генов IFN-β. MP-12 NS, но не R173A NS связывает Wt PKR. R173A NS образовали нитев

Совпадение в аннотации оригинала
Rift Valley fever virus (RVFV) encodes one major virulence factor, the NSs protein. NSs suppresses host general transcription, including int … pecifically lacking the function to promote PKR degradation. rMP12-NSsR173A infection induces early phosphorylation of eIF2α through PKR activation, while retaining the function to inhibit host general transcription including IFN-β gene inhibition. MP-12 NSs but not R173A NSs binds to wt PKR. R173A NSs formed filamentous structure in nucleus in a mosaic pattern, …

Agrin downregulation induced by nerve injury contributes to neuropathic pain.

The elusiveness of neuropathic pain mechanisms is a major impediment in developing effective clinical treatments. Here we show that peripher … essed allodynia and hyperalgesia. Allodynia suppression was a consequence of serine residue 896/897 phosphorylation of NMDA receptor NR1 subunits in the GABA interneurons of the dorsal horn. Agrin silencing by small interference RNA, administered with either AAV-Ag50 vector or SCP1, blocked allodynia suppression, agrin upregulation, and NR1 phosphorylation. In co …