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Viruses Aug 2022Porcine epidemic diarrhea virus (PEDV) has been endemic in most parts of the world since its emergence in the 1970s. It infects the small intestine and intestinal... (Review)
Review
Porcine epidemic diarrhea virus (PEDV) has been endemic in most parts of the world since its emergence in the 1970s. It infects the small intestine and intestinal villous cells, spreads rapidly, and causes infectious intestinal disease characterized by vomiting, diarrhea, and dehydration, leading to high mortality in newborn piglets and causing massive economic losses to the pig industry. The entry of PEDV into cells is mediated by the binding of its spike protein (S protein) to a host cell receptor. Here, we review the structure of PEDV, its strains, and the structure and function of the S protein shared by coronaviruses, and summarize the progress of research on possible host cell receptors since the discovery of PEDV.
Topics: Animals; Coronavirus; Coronavirus Infections; Porcine epidemic diarrhea virus; Spike Glycoprotein, Coronavirus; Swine; Swine Diseases
PubMed: 36016366
DOI: 10.3390/v14081744 -
Genes Jul 2020Ergosterol is an essential component of fungal cell membranes that determines the fluidity, permeability and activity of membrane-associated proteins. Ergosterol... (Review)
Review
Ergosterol is an essential component of fungal cell membranes that determines the fluidity, permeability and activity of membrane-associated proteins. Ergosterol biosynthesis is a complex and highly energy-consuming pathway that involves the participation of many enzymes. Deficiencies in sterol biosynthesis cause pleiotropic defects that limit cellular proliferation and adaptation to stress. Thereby, fungal ergosterol levels are tightly controlled by the bioavailability of particular metabolites (e.g., sterols, oxygen and iron) and environmental conditions. The regulation of ergosterol synthesis is achieved by overlapping mechanisms that include transcriptional expression, feedback inhibition of enzymes and changes in their subcellular localization. In the budding yeast , the sterol regulatory element (SRE)-binding proteins Upc2 and Ecm22, the heme-binding protein Hap1 and the repressor factors Rox1 and Mot3 coordinate ergosterol biosynthesis () gene expression. Here, we summarize the sterol biosynthesis, transport and detoxification systems of , as well as its adaptive response to sterol depletion, low oxygen, hyperosmotic stress and iron deficiency. Because of the large number of genes and the crosstalk between different environmental signals and pathways, many aspects of ergosterol regulation are still unknown. The study of sterol metabolism and its regulation is highly relevant due to its wide applications in antifungal treatments, as well as in food and pharmaceutical industries.
Topics: DNA-Binding Proteins; Drug Resistance, Fungal; Ergosterol; Gene Expression Regulation, Fungal; Promoter Regions, Genetic; Repressor Proteins; Saccharomyces cerevisiae; Saccharomyces cerevisiae Proteins; Sterols; Trans-Activators; Transcription Factors
PubMed: 32679672
DOI: 10.3390/genes11070795 -
Structural basis of ER-associated protein degradation mediated by the Hrd1 ubiquitin ligase complex.Science (New York, N.Y.) Apr 2020Misfolded luminal endoplasmic reticulum (ER) proteins undergo ER-associated degradation (ERAD-L): They are retrotranslocated into the cytosol, polyubiquitinated, and...
Misfolded luminal endoplasmic reticulum (ER) proteins undergo ER-associated degradation (ERAD-L): They are retrotranslocated into the cytosol, polyubiquitinated, and degraded by the proteasome. ERAD-L is mediated by the Hrd1 complex (composed of Hrd1, Hrd3, Der1, Usa1, and Yos9), but the mechanism of retrotranslocation remains mysterious. Here, we report a structure of the active Hrd1 complex, as determined by cryo-electron microscopy analysis of two subcomplexes. Hrd3 and Yos9 jointly create a luminal binding site that recognizes glycosylated substrates. Hrd1 and the rhomboid-like Der1 protein form two "half-channels" with cytosolic and luminal cavities, respectively, and lateral gates facing one another in a thinned membrane region. These structures, along with crosslinking and molecular dynamics simulation results, suggest how a polypeptide loop of an ERAD-L substrate moves through the ER membrane.
Topics: Carrier Proteins; Cryoelectron Microscopy; Endoplasmic Reticulum; Endoplasmic Reticulum-Associated Degradation; Membrane Glycoproteins; Membrane Proteins; Molecular Dynamics Simulation; Multiprotein Complexes; Protein Domains; Protein Folding; Proteolysis; Saccharomyces cerevisiae Proteins; Ubiquitin-Protein Ligases
PubMed: 32327568
DOI: 10.1126/science.aaz2449 -
Nature Apr 2023Structural maintenance of chromosomes (SMC) protein complexes are essential for the spatial organization of chromosomes. Whereas cohesin and condensin organize...
Structural maintenance of chromosomes (SMC) protein complexes are essential for the spatial organization of chromosomes. Whereas cohesin and condensin organize chromosomes by extrusion of DNA loops, the molecular functions of the third eukaryotic SMC complex, Smc5/6, remain largely unknown. Using single-molecule imaging, we show that Smc5/6 forms DNA loops by extrusion. Upon ATP hydrolysis, Smc5/6 reels DNA symmetrically into loops at a force-dependent rate of one kilobase pair per second. Smc5/6 extrudes loops in the form of dimers, whereas monomeric Smc5/6 unidirectionally translocates along DNA. We also find that the subunits Nse5 and Nse6 (Nse5/6) act as negative regulators of loop extrusion. Nse5/6 inhibits loop-extrusion initiation by hindering Smc5/6 dimerization but has no influence on ongoing loop extrusion. Our findings reveal functions of Smc5/6 at the molecular level and establish DNA loop extrusion as a conserved mechanism among eukaryotic SMC complexes.
Topics: Adenosine Triphosphate; Cell Cycle Proteins; Chromosomal Proteins, Non-Histone; Chromosomes, Fungal; DNA, Fungal; Hydrolysis; Multiprotein Complexes; Saccharomyces cerevisiae; Single Molecule Imaging; Cohesins
PubMed: 37076626
DOI: 10.1038/s41586-023-05963-3 -
Frontiers in Immunology 2022Glioma is the most malignant cancer in the brain. As a major vitamin-K-dependent protein in the central nervous system, PROS1 not only plays a vital role in blood...
BACKGROUND
Glioma is the most malignant cancer in the brain. As a major vitamin-K-dependent protein in the central nervous system, PROS1 not only plays a vital role in blood coagulation, and some studies have found that it was associated with tumor immune infiltration. However, the prognostic significance of PROS1 in glioma and the underlying mechanism of PROS1 in shaping the tumor immune microenvironment (TIME) remains unclear.
METHODS
The raw data (including RNA-seq, sgRNA-seq, clinicopathological variables and prognosis, and survival data) were acquired from public databases, including TCGA, GEPIA, CGGA, TIMER, GEO, UALCAN, and CancerSEA. GO enrichment and KEGG pathway analyses were performed using "cluster profiler" package and visualized by the "ggplot2" package. GSEA was conducted using R package "cluster profiler". Tumor immune estimation resource (TIMER) and spearman correlation analysis were applied to evaluate the associations between infiltration levels of immune cells and the expression of PROS1. qRT-PCR and WB were used to assay the expression of PROS1. Wound-healing assay, transwell chambers assays, and CCK-8 assays, were performed to assess migration and proliferation. ROC and KM curves were constructed to determine prognostic significance of PROS1 in glioma.
RESULTS
The level of PROS1 expression was significantly increased in glioma in comparison to normal tissue, which was further certificated by qRT-PCR and WB in LN-229 and U-87MG glioma cells. High expression of PROS1 positively correlated with inflammation, EMT, and invasion identified by CancerSEA, which was also proved by downregulation of PROS1 could suppress cells migration, and proliferation in LN-229 and U-87MG glioma cells. GO and KEGG analysis suggested that PROS1 was involved in disease of immune system and T cell antigen receptor pathway. Immune cell infiltration analysis showed that expression of PROS1 was negatively associated with pDC and NK CD56 bright cells while positively correlated with Macrophages, Neutrophils in glioma. Immune and stromal scores analysis indicated that PROS1 was positively associated with immune score. The high level of PROS1 resulted in an immune suppressive TIME the recruitment of immunosuppressive molecules. In addition, Increased expression of PROS1 was correlated with T-cell exhaustion, M2 polarization, poor Overall-Survival (OS) in glioma. And it was significantly related to tumor histological level, age, primary therapy outcome. The results of our experiment and various bioinformatics approaches validated that PROS1 was a valuable poor prognostic marker.
CONCLUSION
Increased expression of PROS1 was correlated with malignant phenotype and associated with poor prognosis in glioma. Besides, PROS1 could be a possible biomarker and potential immunotherapeutic target through promoting the glioma immunosuppressive microenvironment and inducing tumor-associated macrophages M2 polarization.
Topics: Humans; Tumor Microenvironment; Glioma; Immunosuppression Therapy; Central Nervous System; Immunosuppressive Agents; Protein S
PubMed: 36685506
DOI: 10.3389/fimmu.2022.1052692 -
Best Practice & Research. Clinical... Sep 2022Coronavirus Disease 2019 (COVID-19) has been widely associated with increased thrombotic risk, with many different proposed mechanisms. One such mechanism is acquired... (Review)
Review
Coronavirus Disease 2019 (COVID-19) has been widely associated with increased thrombotic risk, with many different proposed mechanisms. One such mechanism is acquired deficiency of protein S (PS), a plasma protein that regulates coagulation and inflammatory processes, including complement activation and efferocytosis. Acquired PS deficiency is common in patients with severe viral infections and has been reported in multiple studies of COVID-19. This deficiency may be caused by consumption, degradation, or clearance of the protein, by decreased synthesis, or by binding of PS to other plasma proteins, which block its anticoagulant activity. Here, we review the functions of PS, the evidence of acquired PS deficiency in COVID-19 patients, the potential mechanisms of PS deficiency, and the evidence that those mechanisms may be occurring in COVID-19.
Topics: Humans; COVID-19; Protein S; Protein S Deficiency; Thrombosis
PubMed: 36494145
DOI: 10.1016/j.beha.2022.101376 -
Current Opinion in Chemical Biology Dec 2021Protein S-acylation is a prevalent post-translational protein lipidation that is dynamically regulated by 'writer' protein S-acyltransferases and 'eraser' acylprotein... (Review)
Review
Protein S-acylation is a prevalent post-translational protein lipidation that is dynamically regulated by 'writer' protein S-acyltransferases and 'eraser' acylprotein thioesterases. The protein S-acyltransferases comprise 23 aspartate-histidine-histidine-cysteine (DHHC)-containing proteins, which transfer fatty acid acyl groups from acyl-coenzyme A onto protein substrates. DHHC proteins are increasingly recognized as critical regulators of S-acylation-mediated cellular processes and pathology. As our understanding of the importance and breadth of DHHC-mediated biology and pathology expands, so too does the need for chemical inhibitors of this class of proteins. In this review, we discuss the challenges and progress in DHHC inhibitor development, focusing on 2-bromopalmitate, the most commonly used inhibitor in the field, and N-cyanomethyl-N-myracrylamide, a new broad-spectrum DHHC inhibitor. We believe that current and ongoing advances in structure elucidation, mechanistic interrogation, and novel inhibitor design around DHHC proteins will spark innovative strategies to modulate these critical proteins in living systems.
Topics: Acylation; Acyltransferases; Cysteine; Lipoylation; Protein Processing, Post-Translational
PubMed: 34467875
DOI: 10.1016/j.cbpa.2021.07.002 -
Frontiers in Molecular Biosciences 2021Protein S-acylation is the reversible addition of fatty acids to the cysteine residues of target proteins. It regulates multiple aspects of protein function, including... (Review)
Review
Protein S-acylation is the reversible addition of fatty acids to the cysteine residues of target proteins. It regulates multiple aspects of protein function, including the localization to membranes, intracellular trafficking, protein interactions, protein stability, and protein conformation. This process is regulated by palmitoyl acyltransferases that have the conserved amino acid sequence DHHC at their active site. Although they have conserved catalytic cores, DHHC enzymes vary in their protein substrate selection, lipid substrate preference, and regulatory mechanisms. Alterations in DHHC enzyme function are associated with many human diseases, including cancers and neurological conditions. The removal of fatty acids from acylated cysteine residues is catalyzed by acyl protein thioesterases. Notably, S-acylation is now known to be a highly dynamic process, and plays crucial roles in signaling transduction in various cell types. In this review, we will explore the recent findings on protein S-acylation, the enzymatic regulation of this process, and discuss examples of dynamic S-acylation.
PubMed: 33981723
DOI: 10.3389/fmolb.2021.656440