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Yoon HS, Choi SH, Park JH, Min JY, Hyon JY, Yang Y, Jung S, Kim JY, Kim ND, Lee JH, Han EH, Chi SG, Chung YH. A Novel Protein-Protein Interaction between RSK3 and IκBα and a New Binding Inhibitor That Suppresses Breast Cancer Tumorigenesis. Cancers (Basel) 2021; 13:2973. [PMID: 34198590 DOI: 10.3390/cancers13122973] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 05/14/2021] [Accepted: 05/25/2021] [Indexed: 11/16/2022] Open
Abstract
Multiple cancer-related biological processes are mediated by protein-protein interactions (PPIs). Through interactions with a variety of factors, members of the ribosomal S6 kinase (RSK) family play roles in cell cycle progression and cell proliferation. In particular, RSK3 contributes to cancer viability, but the underlying mechanisms remain unknown. We performed a kinase library screen to find IκBα PPI binding partners and identified RSK3 as a novel IκBα binding partner using a cell-based distribution assay. In addition, we discovered a new PPI inhibitor using mammalian two-hybrid (MTH) analysis. We assessed the antitumor effects of the new inhibitor using cell proliferation and colony formation assays and monitored the rate of cell death by FACS apoptosis assay. IκBα is phosphorylated by the active form of the RSK3 kinase. A small-molecule inhibitor that targets the RSK3/IκBα complex exhibited antitumor activity in breast cancer cells and increased their rate of apoptosis. RSK3 phosphorylation and RSK3/IκBα complex formation might be functionally important in breast tumorigenesis. The RSK3/IκBα-specific binding inhibitor identified in this study represents a lead compound for the development of new anticancer drugs.
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Gniffke EP, Harrington WE, Dambrauskas N, Jiang Y, Trakhimets O, Vigdorovich V, Frenkel L, Sather DN, Smith SEP. Plasma From Recovered COVID-19 Patients Inhibits Spike Protein Binding to ACE2 in a Microsphere-Based Inhibition Assay. J Infect Dis 2020; 222:1965-1973. [PMID: 32798222 PMCID: PMC7454725 DOI: 10.1093/infdis/jiaa508] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Accepted: 08/06/2020] [Indexed: 12/16/2022] Open
Abstract
We present a microsphere-based flow cytometry assay that quantifies the ability of plasma to inhibit the binding of spike protein to angiotensin-converting enzyme 2. Plasma from 22 patients who had recovered from mild coronavirus disease 2019 (COVID-19) and expressed anti–spike protein trimer immunoglobulin G inhibited angiotensin-converting enzyme 2–spike protein binding to a greater degree than controls. The degree of inhibition was correlated with anti–spike protein immunoglobulin G levels, neutralizing titers in a pseudotyped lentiviral assay, and the presence of fever during illness. This inhibition assay may be broadly useful to quantify the functional antibody response of patients recovered from COVID-19 or vaccine recipients in a cell-free assay system.
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Affiliation(s)
- Edward P Gniffke
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, Washington, USA
| | - Whitney E Harrington
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, Washington, USA.,Department of Pediatrics, University of Washington, Seattle, Washington, USA
| | - Nicholas Dambrauskas
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, Washington, USA
| | - Yonghou Jiang
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, Washington, USA
| | - Olesya Trakhimets
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, Washington, USA
| | - Vladimir Vigdorovich
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, Washington, USA
| | - Lisa Frenkel
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, Washington, USA.,Department of Pediatrics, University of Washington, Seattle, Washington, USA
| | - D Noah Sather
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, Washington, USA.,Department of Pediatrics, University of Washington, Seattle, Washington, USA
| | - Stephen E P Smith
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, Washington, USA.,Department of Pediatrics, University of Washington, Seattle, Washington, USA.,Graduate Program in Neuroscience, University of Washington, Seattle, Washington, USA
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Doritchamou J, Teo A, Morrison R, Arora G, Kwan J, Manzella-Lapeira J, Medina-Maldonado S, Langhorne J, Hviid L, Narum DL, Dicko A, Fried M, Duffy PE. Functional Antibodies against Placental Malaria Parasites Are Variant Dependent and Differ by Geographic Region. Infect Immun 2019; 87:e00865-18. [PMID: 30988054 DOI: 10.1128/IAI.00865-18] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Accepted: 04/05/2019] [Indexed: 02/06/2023] Open
Abstract
During pregnancy, Plasmodium falciparum-infected erythrocytes (IE) accumulate in the intervillous spaces of the placenta by binding to chondroitin sulfate A (CSA) and elicit inflammatory responses that are associated with poor pregnancy outcomes. Primigravidae lack immunity to IE that sequester in the placenta and thus are susceptible to placental malaria (PM). Women become resistant to PM over successive pregnancies as antibodies to placental IE are acquired. Here, we assayed plasma collected at delivery from Malian and Tanzanian women of different parities for total antibody levels against recombinant VAR2CSA antigens (FCR3 allele), and for surface reactivity and binding inhibition and opsonizing functional activities against IE using two CSA-binding laboratory isolates (FCR3 and NF54). Overall, antibody reactivity to VAR2CSA recombinant proteins and to CSA-binding IE was higher in multigravidae than in primigravidae. However, plasma from Malian gravid women reacted more strongly with FCR3 whereas Tanzanian plasma preferentially reacted with NF54. Further, acquisition of functional antibodies was variant dependent: binding inhibition of P. falciparum strain NF54 (P < 0.001) but not of the strain FCR3 increased significantly with parity, while only opsonizing activity against FCR3 (P < 0.001) increased significantly with parity. In addition, opsonizing and binding inhibition activities of plasma of multigravidae were significantly correlated in assays of FCR3 (r = 0.4, P = 0.01) but not of NF54 isolates; functional activities did not correlate in plasma from primigravidae. These data suggest that IE surface-expressed epitopes involved in each functional activity differ among P. falciparum strains. Consequently, geographic bias in circulating strains may impact antibody functions. Our study has implications for the development of PM vaccines aiming to achieve broad protection against various parasite strains.
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Müller M, Lauster D, Wildenauer HHK, Herrmann A, Block S. Mobility-Based Quantification of Multivalent Virus-Receptor Interactions: New Insights Into Influenza A Virus Binding Mode. Nano Lett 2019; 19:1875-1882. [PMID: 30719917 DOI: 10.1021/acs.nanolett.8b04969] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Viruses, such as influenza A, typically bind to the plasma membrane of their host by engaging multiple membrane receptors in parallel, thereby forming so-called multivalent interactions that are created by the collective action of multiple weak ligand-receptor bonds. The overall interaction strength can be modulated by changing the number of engaged receptors. This feature is used by viruses to achieve a sufficiently firm attachment to the host's plasma membrane but also allows progeny viruses to leave the plasma membrane after completing the virus replication cycle. Design of strategies to prevent infection, for example, by disturbing these attachment and detachment processes upon application of antivirals, requires quantification of the underlying multivalent interaction in absence and presence of antivirals. This is still an unresolved problem, as there is currently no approach available that allows for determining the valency (i.e., of the number of receptors bound to a particular virus) on the level of single viruses under equilibrium conditions. Herein, we track the motion of single influenza A/X31 viruses (IAVs; interacting with the ganglioside GD1a incorporated in a supported lipid bilayer) using total internal reflection fluorescence microscopy and show that IAV residence time distributions can be deconvoluted from valency effects by taking the IAV mobility into account. The so-derived off-rate distributions, expressed in dependence of an average, apparent valency, show the expected decrease in off-rate with increasing valency but also show an unexpected peak structure, which can be linked to a competition in the opposing functionalities of the two influenza A virus spike proteins, hemagglutinin (HA), and neuraminidase (NA). By application of the antiviral zanamivir that inhibits the activity of NA, we provide direct evidence, how the HA/NA balance modulates this virus-receptor interaction, allowing us to assess the inhibition concentration of zanamivir based on its effect on the multivalent interaction.
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Affiliation(s)
- Matthias Müller
- Department of Chemistry and Biochemistry, Emmy-Noether Group "Bionanointerfaces" , Freie Universität Berlin , Takustrasse 3 , 14195 Berlin , Germany
| | - Daniel Lauster
- Department of Biology, Molecular Biophysics , Humboldt-Universität zu Berlin, IRI Life Sciences , Invalidenstr. 42 , 10115 Berlin , Germany
| | - Helen H K Wildenauer
- Department of Chemistry and Biochemistry, Emmy-Noether Group "Bionanointerfaces" , Freie Universität Berlin , Takustrasse 3 , 14195 Berlin , Germany
| | - Andreas Herrmann
- Department of Biology, Molecular Biophysics , Humboldt-Universität zu Berlin, IRI Life Sciences , Invalidenstr. 42 , 10115 Berlin , Germany
| | - Stephan Block
- Department of Chemistry and Biochemistry, Emmy-Noether Group "Bionanointerfaces" , Freie Universität Berlin , Takustrasse 3 , 14195 Berlin , Germany
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Irani V, Ramsland PA, Guy AJ, Siba PM, Mueller I, Richards JS, Beeson JG. Acquisition of Functional Antibodies That Block the Binding of Erythrocyte-Binding Antigen 175 and Protection Against Plasmodium falciparum Malaria in Children. Clin Infect Dis 2015; 61:1244-52. [PMID: 26136391 DOI: 10.1093/cid/civ525] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Accepted: 05/22/2015] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND The targets and mechanisms of human immunity to malaria are poorly understood, which poses a major barrier to malaria vaccine development. Antibodies play a key role in human immunity and may act by inhibiting receptor-binding functions of key merozoite invasion ligands. Antibodies to the major invasion ligand and vaccine candidate, erythrocyte-binding antigen 175 (EBA-175), have been linked with protection, but how these antibodies function has not been established. METHODS We developed 2 new assays that quantify the ability of antibodies to inhibit binding of EBA-175 to its erythrocyte receptor, glycophorin A, using either native or recombinant EBA-175. Binding-inhibitory antibodies were evaluated in a longitudinal cohort study of Papua New Guinean children and related to risk of malaria, age, infection status, and markers of parasite exposure. RESULTS Binding-inhibition assays (BIAs) were reproducible, and the 2 assays had a high level of agreement. Inhibitory antibodies were common among children, acquired in association with markers of increasing parasite exposure, and high in those children with active infection. Inhibitory antibodies correlated with total immunoglobulin G levels to the EBA-175 binding domain (region II). Importantly, binding-inhibitory antibodies were significantly associated with protection from symptomatic malaria when measured using either BIA. CONCLUSIONS Findings suggest that naturally acquired binding-inhibitory antibodies are an important functional mechanism that contributes to protection against malaria and further supports the potential of EBA-175 as a vaccine candidate. Identifying vaccines and approaches that induce potent binding-inhibitory antibodies may be a valuable strategy in the development of highly efficacious malaria vaccines.
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Affiliation(s)
- Vashti Irani
- Centre for Biomedical Research, Burnet Institute, Melbourne Department of Medicine, University of Melbourne, Parkville Department of Immunology, Monash University, Melbourne
| | - Paul A Ramsland
- Centre for Biomedical Research, Burnet Institute, Melbourne Department of Immunology, Monash University, Melbourne Department of Surgery, Austin Health, University of Melbourne, Heidelberg, Victoria School of Biomedical Sciences, Curtin Health Innovation Research Institute-Biosciences, Curtin University, Perth, Western Australia, Australia
| | - Andrew J Guy
- Centre for Biomedical Research, Burnet Institute, Melbourne Department of Immunology, Monash University, Melbourne
| | - Peter M Siba
- Papua New Guinea Institute of Medical Research, Goroka
| | - Ivo Mueller
- Infection and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia Barcelona Centre for International Health Research, Spain
| | - Jack S Richards
- Centre for Biomedical Research, Burnet Institute, Melbourne Department of Medicine, University of Melbourne, Parkville Department of Microbiology, Monash University, Clayton, Victoria, Australia
| | - James G Beeson
- Centre for Biomedical Research, Burnet Institute, Melbourne Department of Medicine, University of Melbourne, Parkville Department of Microbiology, Monash University, Clayton, Victoria, Australia
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Takai M, Kozai Y, Tsuzuki S, Matsuno Y, Fujioka M, Kamei K, Inagaki H, Eguchi A, Matsumura S, Inoue K, Fushiki T. Unsaturated long-chain fatty acids inhibit the binding of oxidized low-density lipoproteins to a model CD36. Biosci Biotechnol Biochem 2014; 78:238-44. [PMID: 25036676 DOI: 10.1080/09168451.2014.882750] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Transmembrane protein CD36 binds multiple ligands, including oxidized low-density lipoproteins (oxLDLs) and long-chain fatty acids (LCFAs). Our aim was to determine whether LCFAs compete with oxLDLs for binding to CD36. We addressed this issue by examining the inhibitory effect of LCFAs against the binding of Alexa-fluor-labeled oxLDLs (AFL-oxLDL) to a synthetic peptide representing the oxLDL-binding site on CD36 (3S-CD36₁₅₀₋₁₆₈). All of the unsaturated LCFAs tested, inhibited the binding of AFL-oxLDL to 3S-CD36₁₅₀₋₁₆₈, albeit to varying degrees. For instance, the concentrations required for 50% inhibition of binding for oleic, linoleic, and α-linolenic acids were 0.25, 0.97, and 1.2 mM, respectively. None of the saturated LCFAs tested (e.g. stearic acid) exhibited inhibitory effects. These results suggest that at least unsaturated LCFAs can compete with oxLDLs for binding to CD36. The study also provides information on the structural requirements of LCFAs for inhibition of oxLDLs-CD36 binding.
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Affiliation(s)
- Marie Takai
- a Laboratory of Nutrition Chemistry, Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University , Kyoto , Japan
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