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Advances in Experimental Medicine and... 2020The cell cycle is a sophisticated space-time regulated mechanism where a wide variety of protein modules and complexes associate functioning in a concerted manner to... (Review)
Review
The cell cycle is a sophisticated space-time regulated mechanism where a wide variety of protein modules and complexes associate functioning in a concerted manner to regulate and transfer the genetic material to daughter cells. CCT (chaperonin containing TCP-1, also known as TRiC) is a molecular machine that forms a high molecular weight complex (1000 KDa). CCT is emerging as a key molecule during mitosis due to its essential role in the folding of many important proteins involved in cell division (Cdh1, Plk1, p27, Cdc20, PP2a regulatory subunits, tubulin or actin) suggesting its involvement in uncontrolled proliferation. The assembly is formed by eight different subunits called CCTα, β, γ, δ, ε, ζ, η and θ in mammals corresponding to CCT1-8 in yeast. CCT/TRiC is organized in a unique intra- and inter-ring arrangement. The chaperonin monomers share a common domain structure including an equatorial domain, which contains all the inter-ring contacts, most of the intra-ring contacts and the ATP binding site, whose binding and hydrolysis triggers the conformational changes that take place during the functional cycle. All chaperonins display an open substrate-receptive conformation, where the unfolded protein is recognized and trapped, and a closed conformation where the substrate is isolated from the bulk of the intracellular environment. In this chapter we discuss the complex set of intra- and inter-ring allosteric signals during chaperonin function.
Topics: Allosteric Regulation; Animals; Cell Proliferation; Chaperonin Containing TCP-1; Humans; Mitosis; Protein Folding; Protein Subunits
PubMed: 32297209
DOI: 10.1007/978-3-030-40204-4_2 -
Cellular & Molecular Immunology May 2022Neutrophil extracellular traps (NETs) can capture and kill viruses, such as influenza viruses, human immunodeficiency virus (HIV), and respiratory syncytial virus (RSV),...
Neutrophil extracellular traps (NETs) can capture and kill viruses, such as influenza viruses, human immunodeficiency virus (HIV), and respiratory syncytial virus (RSV), thus contributing to host defense. Contrary to our expectation, we show here that the histones released by NETosis enhance the infectivity of SARS-CoV-2, as found by using live SARS-CoV-2 and two pseudovirus systems as well as a mouse model. The histone H3 or H4 selectively binds to subunit 2 of the spike (S) protein, as shown by a biochemical binding assay, surface plasmon resonance and binding energy calculation as well as the construction of a mutant S protein by replacing four acidic amino acids. Sialic acid on the host cell surface is the key molecule to which histones bridge subunit 2 of the S protein. Moreover, histones enhance cell-cell fusion. Finally, treatment with an inhibitor of NETosis, histone H3 or H4, or sialic acid notably affected the levels of sgRNA copies and the number of apoptotic cells in a mouse model. These findings suggest that SARS-CoV-2 could hijack histones from neutrophil NETosis to promote its host cell attachment and entry process and may be important in exploring pathogenesis and possible strategies to develop new effective therapies for COVID-19.
Topics: Animals; COVID-19; Histones; Mice; N-Acetylneuraminic Acid; Protein Subunits; SARS-CoV-2; Spike Glycoprotein, Coronavirus; Virus Internalization
PubMed: 35273357
DOI: 10.1038/s41423-022-00845-6 -
Open Biology Jun 2021Herpes simplex virus type 1 (HSV-1) is one of the nine herpesviruses that infect humans. HSV-1 encodes seven proteins to replicate its genome in the hijacked human cell.... (Review)
Review
Herpes simplex virus type 1 (HSV-1) is one of the nine herpesviruses that infect humans. HSV-1 encodes seven proteins to replicate its genome in the hijacked human cell. Among these are the herpes virus DNA helicase and primase that are essential components of its replication machinery. In the HSV-1 replisome, the helicase-primase complex is composed of three components including UL5 (helicase), UL52 (primase) and UL8 (non-catalytic subunit). UL5 and UL52 subunits are functionally interdependent, and the UL8 component is required for the coordination of UL5 and UL52 activities proceeding in opposite directions with respect to the viral replication fork. Anti-viral compounds currently under development target the functions of UL5 and UL52. Here, we review the structural and functional properties of the UL5/UL8/UL52 complex and highlight the gaps in knowledge to be filled to facilitate molecular characterization of the structure and function of the helicase-primase complex for development of alternative anti-viral treatments.
Topics: Animals; Antiviral Agents; DNA Helicases; DNA Primase; Drug Development; Herpes Simplex; Herpesvirus 1, Human; Humans; Models, Molecular; Multienzyme Complexes; Protein Binding; Protein Interaction Domains and Motifs; Protein Subunits; Structure-Activity Relationship; Virus Replication
PubMed: 34102080
DOI: 10.1098/rsob.210011 -
International Journal of Molecular... Jul 2023Protein phosphatase 2A (PP2A) is a strongly conserved and major protein phosphatase in all eukaryotes. The canonical PP2A complex consists of a catalytic (C),... (Review)
Review
Protein phosphatase 2A (PP2A) is a strongly conserved and major protein phosphatase in all eukaryotes. The canonical PP2A complex consists of a catalytic (C), scaffolding (A), and regulatory (B) subunit. Plants have three groups of evolutionary distinct B subunits: B55, B' (B56), and B''. Here, the Arabidopsis B' group is reviewed and compared with other eukaryotes. Members of the B'α/B'β clade are especially important for chromatid cohesion, and dephosphorylation of transcription factors that mediate brassinosteroid (BR) signaling in the nucleus. Other B' subunits interact with proteins at the cell membrane to dampen BR signaling or harness immune responses. The transition from vegetative to reproductive phase is influenced differentially by distinct B' subunits; B'α and B'β being of little importance, whereas others (B'γ, B'ζ, B'η, B'θ, B'κ) promote transition to flowering. Interestingly, the latter B' subunits have three motifs in a conserved manner, i.e., two docking sites for protein phosphatase 1 (PP1), and a POLO consensus phosphorylation site between these motifs. This supports the view that a conserved PP1-PP2A dephosphorelay is important in a variety of signaling contexts throughout eukaryotes. A profound understanding of these regulators may help in designing future crops and understand environmental issues.
Topics: Arabidopsis; Arabidopsis Proteins; Phosphorylation; Physiological Phenomena; Protein Phosphatase 2; Protein Subunits; Transcription Factors
PubMed: 37569631
DOI: 10.3390/ijms241512255 -
Hypertension (Dallas, Tex. : 1979) Jun 2023Vascular smooth muscle cell (VSMC) contractility is critical for blood pressure regulation and vascular homeostasis. Identifying the key molecule that maintains VSMC...
Activin Receptor-Like Kinase 3 Directly Couples Gαq (Guanine Nucleotide-Binding Protein Subunit αq)/ Gαq (Guanine Nucleotide-Binding Protein Subunit α11) to Regulate Vascular Contractility.
BACKGROUND
Vascular smooth muscle cell (VSMC) contractility is critical for blood pressure regulation and vascular homeostasis. Identifying the key molecule that maintains VSMC contractility may provide a novel therapeutic target for vascular remodeling. ALK3 (activin receptor-like kinase 3) is a serine/threonine kinase receptor, and deletion of ALK3 causes embryonic lethality. However, little is known about the role of ALK3 in postnatal arterial function and homeostasis.
METHODS
We conducted in vivo studies in a tamoxifen-induced postnatal VSMC-specific ALK3 deletion mice suitable for analysis of blood pressure and vascular contractility. Additionally, the role of ALK3 on VSMC was determined using Western blot, collagen-based contraction assay and traction force microscopy. Furthermore, interactome analysis were performed to identify the ALK3-associated proteins and bioluminescence resonance energy transfer assay was used to characterize Gαq activation.
RESULTS
ALK3 deficiency in VSMC led to spontaneous hypotension and impaired response to angiotensin II in mice. In vivo and in vitro data revealed that ALK3 deficiency impaired contraction force generation by VSMCs, repressed the expression of contractile proteins, and inhibited the phosphorylation of myosin light chain. Mechanistically, Smad1/5/8 signaling mediated the ALK3-modulated contractile protein expressions but not myosin light chain phosphorylation. Furthermore, interactome analysis revealed that ALK3 directly interacted with and activated Gαq (guanine nucleotide-binding protein subunit αq)/Gα11 (guanine nucleotide-binding protein subunit α11), thereby stimulating myosin light chain phosphorylation and VSMC contraction.
CONCLUSIONS
Our study revealed that in addition to canonical Smad1/5/8 signaling, ALK3 modulates VSMC contractility through direct interaction with Gαq/Gα11, and therefore, might serve as a potential target for modulating aortic wall homeostasis.
Topics: Mice; Animals; Protein Subunits; Muscle, Smooth, Vascular; Bone Morphogenetic Protein Receptors, Type I; Blood Pressure; GTP-Binding Proteins; Myocytes, Smooth Muscle; Guanine Nucleotides; Cells, Cultured
PubMed: 36999441
DOI: 10.1161/HYPERTENSIONAHA.122.20654 -
High G protein subunit beta 4 protein level is correlated to poor prognosis of urothelial carcinoma.Medical Molecular Morphology Dec 2021Data mining on a public domain detected eight potential transcripts which were upregulated in advanced UBUCs, suggesting that they may take part in UC development or/and...
Data mining on a public domain detected eight potential transcripts which were upregulated in advanced UBUCs, suggesting that they may take part in UC development or/and progression. Retrospectively, immunohistochemistry along with H-score recording was carried out to evaluate the GNB4 protein levels on tissues from UC patients. Correlations between GNB4 H-score and imperative clinicopathological factors, as well as the implication of GNB4 protein level on disease-specific and metastasis-free survivals were assessed. In UTUCs (n = 340) and UBUCs (n = 295), 170 (50.0%) and 148 (50.0%) cases, respectively, were identified to be of high GNB4 expression. The GNB4 protein levels were correlated to numerous clinicopathological features and patients' survivals. Upregulation of the GNB4 protein was significantly associated with primary tumor, nodal metastasis, histological grade, vascular invasion and mitotic rate. High GNB4 protein levels independently and significantly predicted poor disease-specific and metastasis-free in UTUC and UBUC, respectively. Ingenuity pathway analysis furthermore showed that multiple signaling pathways were enriched including 'Communication between Innate and Adaptive Immune Cells' and 'NFκB Signaling'. Our findings demonstrated that the upregulation of the GNB4 protein is an independent unfavorable prognosticator in UC. High GNB4 gene expression plays an important role in UC progression.
Topics: Carcinoma, Transitional Cell; GTP-Binding Protein beta Subunits; Humans; Immunohistochemistry; Protein Subunits; Retrospective Studies; Urinary Bladder Neoplasms
PubMed: 34398348
DOI: 10.1007/s00795-021-00301-w -
Structure (London, England : 1993) Jun 2024Group I chaperonins are dual heptamer protein complexes that play significant roles in protein homeostasis. The structure and function of the Escherichia coli chaperonin...
Group I chaperonins are dual heptamer protein complexes that play significant roles in protein homeostasis. The structure and function of the Escherichia coli chaperonin are well characterized. However, the dynamic properties of chaperonins, such as large ATPase-dependent conformational changes by binding of lid-like co-chaperonin GroES, have made structural analyses challenging, and our understanding of these changes during the turnover of chaperonin complex formation is limited. In this study, we used single-particle cryogenic electron microscopy to investigate the structures of GroES-bound chaperonin complexes from the thermophilic hydrogen-oxidizing bacteria Hydrogenophilus thermoluteolus and Hydrogenobacter thermophilus in the presence of ATP and AMP-PNP. We captured the structure of an intermediate state chaperonin complex, designated as an asymmetric football-shaped complex, and performed analyses to decipher the dynamic structural variations. Our structural analyses of inter- and intra-subunit communications revealed a unique mechanism of complex formation through the binding of a second GroES to a bullet-shaped complex.
Topics: Cryoelectron Microscopy; Models, Molecular; Adenosine Triphosphate; Protein Binding; Chaperonin 10; Bacterial Proteins; Adenylyl Imidodiphosphate; Protein Conformation; Hydrogenophilaceae; Protein Subunits
PubMed: 38492570
DOI: 10.1016/j.str.2024.02.012 -
Proceedings of the National Academy of... Aug 2023Cells of vertebrate and invertebrate organisms express proteins specialized in membrane channel-based cell-cell communication that are absent in unicellular organisms....
Cells of vertebrate and invertebrate organisms express proteins specialized in membrane channel-based cell-cell communication that are absent in unicellular organisms. We recently described the prediction of some members of the large-pore channel family in kinetoplastids, consisting of proteins called unnexins, which share several structural features with innexin and pannexin proteins. Here, we demonstrated that the unnexin1 protein (Unx1) is delivered to the cell membrane, displaying a topology consisting of four transmembrane domains with C and N termini on the cytoplasmic side and form large-pore channels that are permeable to small molecules. Low extracellular Ca/Mg levels or extracellular alkalinization, but not mechanical stretching, increases channel activity. The Unx1 channel mediates the influx of Ca and does not form intercellular dye coupling between HeLa Unx1 transfected cells. Unx1 channel function was further evidenced by its ability to mediate ionic currents when expressed in oocytes. Downregulation of Unx1 mRNA with morpholine contains invasion. Phylogenetic analysis revealed the presence of Unx1 homologs in other protozoan parasites, suggesting a conserved function for these channel parasites in other protists. Our data demonstrate that Unx1 forms large-pore membrane channels, which may serve as a diffusional pathway for ions and small molecules that are likely to be metabolic substrates or waste products, and signaling autocrine and paracrine molecules that could be involved in cell invasion. As morpholinos-induced downregulation of Unx1 reduces the infectivity of trypomastigotes, the Unx1 channels might be an attractive target for developing trypanocide drugs.
Topics: Protein Subunits; Phylogeny; Cell Membrane; Cytoplasm; Morpholinos
PubMed: 37487087
DOI: 10.1073/pnas.2307898120 -
Sub-cellular Biochemistry 2022Neural communication and modulation are complex processes. Ionotropic glutamate receptors (iGluRs) significantly contribute to mediating the fast-excitatory branch of... (Review)
Review
Neural communication and modulation are complex processes. Ionotropic glutamate receptors (iGluRs) significantly contribute to mediating the fast-excitatory branch of neurotransmission in the mammalian brain. Kainate receptors (KARs), a subfamily of the iGluRs, act as modulators of the neuronal circuitry by playing important roles at both the post- and presynaptic sites of specific neurons. The functional tetrameric receptors are formed by two different gene families, low agonist affinity (GluK1-GluK3) and high agonist affinity (GluK4-GluK5) subunits. These receptors garnered attention in the past three decades, and since then, much work has been done to understand their localization, interactome, physiological functions, and regulation. Cloning of the receptor subunits (GluK1-GluK5) in the early 1990s led to recombinant expression of kainate receptors in heterologous systems. This facilitated understanding of the functional differences between subunit combinations, splice variants, trafficking, and drug discovery. Structural studies of individual domains and recent full-length homomeric and heteromeric kainate receptors have revealed unique functional mechanisms, which have answered several long-standing questions in the field of kainate receptor biology. In this chapter, we review the current understanding of kainate receptors and associated disorders.
Topics: Animals; Mammals; Mutation; Protein Subunits; Receptors, Kainic Acid
PubMed: 36151381
DOI: 10.1007/978-3-031-00793-4_10 -
Frontiers in Immunology 2022Under the background of the severe human health and world economic burden caused by COVID-19, the attenuation of vaccine protection efficacy, and the prevalence and...
Under the background of the severe human health and world economic burden caused by COVID-19, the attenuation of vaccine protection efficacy, and the prevalence and immune escape of emerging variants of concern (VOCs), the third dose of booster immunization has been put on the agenda. Systems biology approaches can help us gain new perspectives on the characterization of immune responses and the identification of factors underlying vaccine-induced immune efficacy. We analyzed the antibody signature and transcriptional responses of participants vaccinated with COVID-19 inactivated vaccine and protein subunit vaccine as a third booster dose. The results from the antibody indicated that the third booster dose was effective, and that heterologous vaccination with the protein subunit vaccine as a booster dose induced stronger humoral immune responses than the homologous vaccination with inactivated vaccine, and might be more effective against VOCs. In transcriptomic analysis, protein subunit vaccine induced more differentially expressed genes that were significantly associated with many important innate immune pathways. Both the homologous and heterologous boosters could increase the effectiveness against COVID-19, and compared with the inactivated vaccine, the protein subunit vaccine, mediated a stronger humoral immune response and had a more significant correlation with the innate immune function module, which provided certain data support for the third booster immunization strategy.
Topics: Humans; Immunity, Humoral; Transcriptome; Protein Subunits; Immunization, Secondary; COVID-19; Vaccines, Inactivated; Vaccines, Subunit
PubMed: 36341453
DOI: 10.3389/fimmu.2022.1027180