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Antiviral Research Jun 2024Rift Valley fever virus (RVFV) is an arbovirus in the Phenuiviridae family identified initially by the large 'abortion storms' observed among ruminants; RVFV can also...
Rift Valley fever virus (RVFV) is an arbovirus in the Phenuiviridae family identified initially by the large 'abortion storms' observed among ruminants; RVFV can also infect humans. In humans, there is a wide variation of clinical symptoms ranging from subclinical to mild febrile illness to hepatitis, retinitis, delayed-onset encephalitis, or even hemorrhagic fever. The RVFV is a tri-segmented negative-sense RNA virus consisting of S, M, and L segments. The L segment encodes the RNA-dependent RNA polymerase (RdRp), termed the L protein, which is responsible for both viral mRNA synthesis and genome replication. Phosphorylation of viral RdRps is known to regulate viral replication. This study shows that RVFV L protein is serine phosphorylated and identified Casein Kinase 1 alpha (CK1α) and protein phosphatase 1 alpha (PP1α) as L protein binding partners. Inhibition of CK1 and PP1 through small molecule inhibitor treatment, D4476 and 1E7-03, respectively, caused a change in the phosphorylated status of the L protein. Inhibition of PP1α resulted in increased L protein phosphorylation whereas inhibition of CK1α decreased L protein phosphorylation. It was also found that in RVFV infected cells, PP1α localized to the cytoplasmic compartment. Treatment of RVFV infected cells with CK1 inhibitors reduced virus production in both mammalian and mosquito cells. Lastly, inhibition of either CK1 or PP1 reduced viral genomic RNA levels. These data indicate that L protein is phosphorylated and that CK1 and PP1 play a crucial role in regulating the L protein phosphorylation cycle, which is critical to viral RNA production and viral replication.
Topics: Rift Valley fever virus; Phosphorylation; Virus Replication; Humans; Animals; Protein Phosphatase 1; Genome, Viral; Viral Proteins; Casein Kinase Ialpha; Chlorocebus aethiops; Cell Line; RNA-Dependent RNA Polymerase; Vero Cells; RNA, Viral; Rift Valley Fever
PubMed: 38679165
DOI: 10.1016/j.antiviral.2024.105895 -
Biochemical and Biophysical Research... Jun 2024Megakaryopoiesis and platelet production is a complex process that is underpotential regulation at multiple stages. Many long non-coding RNAs (lncRNAs) are distributed...
Megakaryopoiesis and platelet production is a complex process that is underpotential regulation at multiple stages. Many long non-coding RNAs (lncRNAs) are distributed in hematopoietic stem cells and platelets. lncRNAs may play important roles as key epigenetic regulators in megakaryocyte differentiation and proplatelet formation. lncRNA NORAD can affect cell ploidy by sequestering PUMILIO proteins, although its direct effect on megakaryocyte differentiation and thrombopoiesis is still unknown. In this study, we demonstrate NORAD RNA is highly expressed in the cytoplasm during megakaryocyte differentiation. Interestingly, we identified for the first time that NORAD has a strong inhibitory effect on megakaryocyte differentiation and proplatelet formation from cultured megakaryocytes. DUSP6/ERK1/2 pathway is activated in response to NORAD knockdown during megakaryocytopoiesis, which is achieved by sequestering PUM2 proteins. Finally, compared with the wild-type control mice, NORAD knockout mice show a faster platelet recovery after severe thrombocytopenia induced by 6 Gy total body irradiation. These findings demonstrate lncRNA NORAD has a key role in regulating megakaryocyte differentiation and thrombopoiesis, which provides a promising molecular target for the treatment of platelet-related diseases such as severe thrombocytopenia.
Topics: Animals; Humans; Mice; Blood Platelets; Cell Differentiation; Cells, Cultured; Dual Specificity Phosphatase 6; MAP Kinase Signaling System; Megakaryocytes; Mice, Inbred C57BL; Mice, Knockout; RNA, Long Noncoding; Thrombocytopenia; Thrombopoiesis
PubMed: 38678784
DOI: 10.1016/j.bbrc.2024.150004 -
Cell Reports May 2024Cell cycle control relies on a delicate balance of phosphorylation with CDK1 and phosphatases like PP1 and PP2A-B55. Yet, identifying the primary substrate responsible...
Cell cycle control relies on a delicate balance of phosphorylation with CDK1 and phosphatases like PP1 and PP2A-B55. Yet, identifying the primary substrate responsible for cell cycle oscillations remains a challenge. We uncover the pivotal role of phospho-regulation in the anaphase-promoting complex/cyclosome (APC/C), particularly through the Apc1-loop domain (Apc1-300L), orchestrated by CDK1 and PP2A-B55. Premature activation of PP2A-B55 during mitosis, induced by Greatwall kinase depletion, leads to Apc1-300L dephosphorylation, stalling APC/C activity and delaying Cyclin B degradation. This effect can be counteracted using the B55-specific inhibitor pEnsa or by removing Apc1-300L. We also show Cdc20's dynamic APC/C interaction across cell cycle stages, but dephosphorylation of Apc1-300L specifically inhibits further Cdc20 recruitment. Our study underscores APC/C's central role in cell cycle oscillation, identifying it as a primary substrate regulated by the CDK-PP2A partnership.
Topics: Animals; Anaphase-Promoting Complex-Cyclosome; Apc1 Subunit, Anaphase-Promoting Complex-Cyclosome; CDC2 Protein Kinase; Cdc20 Proteins; Cell Cycle; Mitosis; Phosphorylation; Protein Phosphatase 2; Sf9 Cells; Xenopus
PubMed: 38678563
DOI: 10.1016/j.celrep.2024.114155 -
Animal Reproduction Science Jun 2024The anterior pituitary plays a critical role in the endocrine system, contains gonadotrophs, which regulate reproductive efficiency by secreting follicle-stimulating...
The anterior pituitary plays a critical role in the endocrine system, contains gonadotrophs, which regulate reproductive efficiency by secreting follicle-stimulating hormone (FSH) and luteinizing hormone (LH). PPP2R2A is a serine-threonine phosphatase that regulates reproductive functions in both females and males, its function in pituitary cells remain unclear. Hu sheep is a highly prolific breed, which makes it suitable for studying reproductive mechanisms. In this study, the relative abundances of PPP2R2A mRNA expression were higher in the pituitary of high-prolificacy (HF) Hu sheep compared to those of low-prolificacy (LF) Hu sheep. Additionally, we demonstrated that PPP2R2A promotes pituitary cell proliferation and gonadotropin secretion using the EdU assay and ELISA, respectively. Moreover, it inhibits pituitary cell apoptosis using flow cytometry. Furthermore, PPP2R2A may affect pituitary cell function by regulating the AKT/mTOR signaling pathway. In summary, our findings suggest that PPP2R2A may play a role in regulating pituitary function and influencing the secretion of gonadotropins.
Topics: Animals; Protein Phosphatase 2; Sheep; Pituitary Gland; Female; Cell Proliferation; Gonadotropins; Male; Gene Expression Regulation
PubMed: 38677100
DOI: 10.1016/j.anireprosci.2024.107457 -
International Journal of Molecular... Apr 2024DUSPs, a diverse group of protein phosphatases, play a pivotal role in orchestrating cellular growth and development through intricate signaling pathways. Notably, they...
DUSPs, a diverse group of protein phosphatases, play a pivotal role in orchestrating cellular growth and development through intricate signaling pathways. Notably, they actively participate in the MAPK pathway, which governs crucial aspects of plant physiology, including growth regulation, disease resistance, pest resistance, and stress response. DUSP is a key enzyme, and it is the enzyme that limits the rate of cell metabolism. At present, complete understanding of the DUSP gene family in cotton and its specific roles in resistance to (VW) remains elusive. To address this knowledge gap, we conducted a comprehensive identification and analysis of four key cotton species: , , , and . The results revealed the identification of a total of 120 DUSP genes in the four cotton varieties, which were categorized into six subgroups and randomly distributed at both ends of 26 chromosomes, predominantly localized within the nucleus. Our analysis demonstrated that closely related DUSP genes exhibited similarities in terms of the conserved motif composition and gene structure. A promoter analysis performed on the GhDUSP gene promoter revealed the presence of several cis-acting elements, which are associated with abiotic and biotic stress responses, as well as hormone signaling. A tissue expression pattern analysis demonstrated significant variations in GhDUSP gene expression under different stress conditions, with roots exhibiting the highest levels, followed by stems and leaves. In terms of tissue-specific detection, petals, leaves, stems, stamens, and receptacles exhibited higher expression levels of the GhDUSP gene. The gene expression analysis results for GhDUSPs under stress suggest that DUSP genes may have a crucial role in the cotton response to stress in cotton. Through Virus-Induced Gene Silencing (VIGS) experiments, the silencing of the target gene significantly reduced the resistance efficiency of disease-resistant varieties against (VW). Consequently, we conclude that -mediated bispecific phosphorylated genes may serve as key regulators in the resistance of to (VW). This study presents a comprehensive structure designed to provide an in-depth understanding of the potential biological functions of cotton, providing a strong foundation for further research into molecular breeding and resistance to plant pathogens.
Topics: Disease Resistance; Dual-Specificity Phosphatases; Gene Expression Regulation, Plant; Genome, Plant; Gossypium; Phylogeny; Plant Diseases; Plant Proteins; Verticillium
PubMed: 38674085
DOI: 10.3390/ijms25084500 -
International Journal of Molecular... Apr 2024Organ transplantation is associated with various forms of programmed cell death which can accelerate transplant injury and rejection. Targeting cell death in donor...
Organ transplantation is associated with various forms of programmed cell death which can accelerate transplant injury and rejection. Targeting cell death in donor organs may represent a novel strategy for preventing allograft injury. We have previously demonstrated that necroptosis plays a key role in promoting transplant injury. Recently, we have found that mitochondria function is linked to necroptosis. However, it remains unknown how necroptosis signaling pathways regulate mitochondrial function during necroptosis. In this study, we investigated the receptor-interacting protein kinase 3 (RIPK3) mediated mitochondrial dysfunction and necroptosis. We demonstrate that the calmodulin-dependent protein kinase (CaMK) family members CaMK1, 2, and 4 form a complex with RIPK3 in mouse cardiac endothelial cells, to promote trans-phosphorylation during necroptosis. CaMK1 and 4 directly activated the dynamin-related protein-1 (Drp1), while CaMK2 indirectly activated Drp1 via the phosphoglycerate mutase 5 (PGAM5). The inhibition of CaMKs restored mitochondrial function and effectively prevented endothelial cell death. CaMKs inhibition inhibited activation of CaMKs and Drp1, and cell death and heart tissue injury (n = 6/group, < 0.01) in a murine model of cardiac transplantation. Importantly, the inhibition of CaMKs greatly prolonged heart graft survival (n = 8/group, < 0.01). In conclusion, CaMK family members orchestrate cell death in two different pathways and may be potential therapeutic targets in preventing cell death and transplant injury.
Topics: Animals; Mice; Necroptosis; Graft Rejection; Heart Transplantation; Receptor-Interacting Protein Serine-Threonine Kinases; Dynamins; Mitochondria; Endothelial Cells; Male; Mice, Inbred C57BL; Phosphoprotein Phosphatases; Phosphorylation; Calcium-Calmodulin-Dependent Protein Kinases; Calcium-Calmodulin-Dependent Protein Kinase Type 2; Signal Transduction
PubMed: 38674016
DOI: 10.3390/ijms25084428 -
Chemosphere Jun 2024Microcystin-LR (MC-LR) is a harmful cyanotoxin that inhibits 1 and 2A serine-threonine protein phosphatases. This study examines the influence of MC-LR on chloroplast...
Microcystin-LR (MC-LR) is a harmful cyanotoxin that inhibits 1 and 2A serine-threonine protein phosphatases. This study examines the influence of MC-LR on chloroplast division and the underlying mechanisms and consequences in Arabidopsis. MC-LR increased the frequency of dividing chloroplasts in hypocotyls in a time range of 1-96 h. At short-term exposures to MC-LR, small-sized chloroplasts (longitudinal diameters ≤6 μm) were more sensitive to these stimulatory effects, while both small and large chloroplasts showed stimulations at long-term exposure. After 48 h, the cyanotoxin increased the frequency of small-sized chloroplasts, indicating the stimulation of division. MC-LR inhibited protein phosphatases in whole hypocotyls and isolated chloroplasts, while it did not induce oxidative stress. We show for the first time that total cellular phosphatases play important roles in chloroplast division and that particular chloroplast phosphatases may be involved in these processes. Interestingly, MC-LR has a protective effect on cyanobacterial division during methyl-viologen (MV) treatments in Synechococcus PCC6301. MC-LR production has harmful effects on ecosystems and it may have an ancient cell division regulatory role in stressed cyanobacterial cells, the evolutionary ancestors of chloroplasts. We propose that cytoplasmic (eukaryotic) factors also contribute to the relevant effects of MC-LR in plants.
Topics: Microcystins; Chloroplasts; Marine Toxins; Phosphoprotein Phosphatases; Arabidopsis; Cyanobacteria; Cell Division; Synechococcus
PubMed: 38670509
DOI: 10.1016/j.chemosphere.2024.142125 -
Cells Apr 2024Gaucher disease (GD) is caused by glucocerebrosidase (GCase) enzyme deficiency, leading to glycosylceramide (Gb-1) and glucosylsphingosine (Lyso-Gb-1) accumulation. The...
BACKGROUND
Gaucher disease (GD) is caused by glucocerebrosidase (GCase) enzyme deficiency, leading to glycosylceramide (Gb-1) and glucosylsphingosine (Lyso-Gb-1) accumulation. The pathological hallmark for GD is an accumulation of large macrophages called Gaucher cells (GCs) in the liver, spleen, and bone marrow, which are associated with chronic organ enlargement, bone manifestations, and inflammation. Tartrate-resistant acid phosphatase type 5 (TRAP5 protein, gene) has long been a nonspecific biomarker of macrophage/GCs activation; however, the discovery of two isoforms of TRAP5 has expanded its significance. The discovery of TRAP5's two isoforms revealed that it is more than just a biomarker of macrophage activity. While TRAP5a is highly expressed in macrophages, TRAP5b is secreted by osteoclasts. Recently, we have shown that the elevation of TRAP5b in plasma is associated with osteoporosis in GD. However, the role of TRAP isoforms in GD and how the accumulation of Gb-1 and Lyso-Gb-1 affects TRAP expression is unknown.
METHODS
39 patients with GD were categorized into cohorts based on bone mineral density (BMD). TRAP5a and TRAP5b plasma levels were quantified by ELISA. ACP5 mRNA was estimated using RT-PCR.
RESULTS
An increase in TRAP5b was associated with reduced BMD and correlated with Lyso-Gb-1 and immune activator chemokine ligand 18 (CCL18). In contrast, the elevation of TRAP5a correlated with chitotriosidase activity in GD. Lyso-Gb-1 and plasma seemed to influence the expression of ACP5 in macrophages.
CONCLUSIONS
As an early indicator of BMD alteration, measurement of circulating TRAP5b is a valuable tool for assessing osteopenia-osteoporosis in GD, while TRAP5a serves as a biomarker of macrophage activation in GD. Understanding the distinct expression pattern of TRAP5 isoforms offers valuable insight into both bone disease and the broader implications for immune system activation in GD.
Topics: Gaucher Disease; Humans; Tartrate-Resistant Acid Phosphatase; Protein Isoforms; Female; Male; Middle Aged; Adult; Bone Density; Macrophages; Biomarkers; Isoenzymes
PubMed: 38667330
DOI: 10.3390/cells13080716 -
Cells Apr 2024Variants of mitochondrial DNA (mtDNA) have been identified as risk factors for the development of Parkinson's disease (PD). However, the underlying pathogenetic...
Variants of mitochondrial DNA (mtDNA) have been identified as risk factors for the development of Parkinson's disease (PD). However, the underlying pathogenetic mechanisms remain unclear. Cybrid models carrying various genotypes of mtDNA variants were tested for resistance to PD-simulating MPP treatment. The most resistant line was selected for transcriptome profiling, revealing specific genes potentially influencing the resistant characteristic. We then conducted protein validation and molecular biological studies to validate the related pathways as the influential factor. Cybrids carrying the W3 mtDNA haplogroup demonstrated the most resistance to the MPP treatment. In the transcriptome study, was identified, while further study noted elevated expressions of the coding protein GADD34 across all cybrids. In the study of GADD34-related mitochondrial unfolding protein response (mtUPR), we found that canonical mtUPR, launched by the phosphate eIF2a, is involved in the resistant characteristic of specific mtDNA to MPP treatment. Our study suggests that a lower expression of GADD34 in the late phase of mtUPR may prolong the mtUPR process, thereby benefitting protein homeostasis and facilitating cellular resistance to PD development. We herein demonstrate that GADD34 plays an important role in PD development and should be further investigated as a target for the development of therapies for PD.
Topics: Parkinson Disease; Humans; DNA, Mitochondrial; Haplotypes; Protein Phosphatase 1; Mitochondria; Unfolded Protein Response
PubMed: 38667309
DOI: 10.3390/cells13080694 -
Cells Apr 2024Toll-like receptors (TLRs) induce innate immune responses through activation of intracellular signaling pathways, such as MAP kinase and NF-κB signaling pathways, and...
Toll-like receptors (TLRs) induce innate immune responses through activation of intracellular signaling pathways, such as MAP kinase and NF-κB signaling pathways, and play an important role in host defense against bacterial or viral infections. Meanwhile, excessive activation of TLR signaling leads to a variety of inflammatory disorders, including autoimmune diseases. TLR signaling is therefore strictly controlled to balance optimal immune response and inflammation. However, its balancing mechanisms are not fully understood. In this study, we identified the E3 ubiquitin ligase LINCR/ NEURL3 as a critical regulator of TLR signaling. In LINCR-deficient cells, the sustained activation of JNK and p38 MAPKs induced by the agonists for TLR3, TLR4, and TLR5, was clearly attenuated. Consistent with these observations, TLR-induced production of a series of inflammatory cytokines was significantly attenuated, suggesting that LINCR positively regulates innate immune responses by promoting the activation of JNK and p38. Interestingly, our further mechanistic study identified MAPK phosphatase-1 (MKP1), a negative regulator of MAP kinases, as a ubiquitination target of LINCR. Thus, our results demonstrate that TLRs fine-tune the activation of MAP kinase pathways by balancing LINCR (the positive regulator) and MKP1 (the negative regulator), which may contribute to the induction of optimal immune responses.
Topics: Dual Specificity Phosphatase 1; Toll-Like Receptors; Ubiquitin-Protein Ligases; Animals; Ubiquitination; Humans; Signal Transduction; Mice; Proteolysis; Immunity, Innate; p38 Mitogen-Activated Protein Kinases; HEK293 Cells; Cytokines
PubMed: 38667302
DOI: 10.3390/cells13080687