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Full-Text Articles in Amino Acids, Peptides, and Proteins

Iiv-6 Inhibits Nf-Kappab Responses In Drosophila, Cara C. West, Florentina Rus, Ying Chen, Anni Kleino, Monique Gangloff, Don B. Gammon, Neal S. Silverman Jul 2019

Iiv-6 Inhibits Nf-Kappab Responses In Drosophila, Cara C. West, Florentina Rus, Ying Chen, Anni Kleino, Monique Gangloff, Don B. Gammon, Neal S. Silverman

Neal Silverman

The host immune response and virus-encoded immune evasion proteins pose constant, mutual selective pressure on each other. Virally encoded immune evasion proteins also indicate which host pathways must be inhibited to allow for viral replication. Here, we show that IIV-6 is capable of inhibiting the two Drosophila NF-kappaB signaling pathways, Imd and Toll. Antimicrobial peptide (AMP) gene induction downstream of either pathway is suppressed when cells infected with IIV-6 are also stimulated with Toll or Imd ligands. We find that cleavage of both Imd and Relish, as well as Relish nuclear translocation, three key points in Imd signal transduction, occur …


Control Of Antiviral Innate Immune Response By Protein Geranylgeranylation, Shigao Yang, Zhaozhao Jiang, Katherine A. Fitzgerald, Donghai Wang Jul 2019

Control Of Antiviral Innate Immune Response By Protein Geranylgeranylation, Shigao Yang, Zhaozhao Jiang, Katherine A. Fitzgerald, Donghai Wang

Katherine A. Fitzgerald

The mitochondrial antiviral signaling protein (MAVS) orchestrates host antiviral innate immune response to RNA virus infection. However, how MAVS signaling is controlled to eradicate virus while preventing self-destructive inflammation remains obscure. Here, we show that protein geranylgeranylation, a posttranslational lipid modification of proteins, limits MAVS-mediated immune signaling by targeting Rho family small guanosine triphosphatase Rac1 into the mitochondria-associated endoplasmic reticulum (ER) membranes (MAMs) at the mitochondria-ER junction. Protein geranylgeranylation and subsequent palmitoylation promote Rac1 translocation into MAMs upon viral infection. MAM-localized Rac1 limits MAVS' interaction with E3 ligase Trim31 and hence inhibits MAVS ubiquitination, aggregation, and activation. Rac1 also facilitates …


Vegf/Neuropilin Signaling In Cancer Stem Cells, Arthur M. Mercurio Mar 2019

Vegf/Neuropilin Signaling In Cancer Stem Cells, Arthur M. Mercurio

Arthur M. Mercurio

The function of vascular endothelial growth factor (VEGF) in cancer extends beyond angiogenesis and vascular permeability. Specifically, VEGF-mediated signaling occurs in tumor cells and this signaling contributes to key aspects of tumorigenesis including the self-renewal and survival of cancer stem cells (CSCs). In addition to VEGF receptor tyrosine kinases, the neuropilins (NRPs) are critical for mediating the effects of VEGF on CSCs, primarily because of their ability to impact the function of growth factor receptors and integrins. VEGF/NRP signaling can regulate the expression and function of key molecules that have been implicated in CSC function including Rho family guanosine triphosphatases …


Inhibition Of Triggering Receptor Expressed On Myeloid Cells 1 Ameliorates Inflammation And Macrophage And Neutrophil Activation In Alcoholic Liver Disease In Mice, David Tornai, Istvan Furi, Zu T. Shen, Alexander B. Sigalov, Sahin Coban, Gyongyi Szabo Mar 2019

Inhibition Of Triggering Receptor Expressed On Myeloid Cells 1 Ameliorates Inflammation And Macrophage And Neutrophil Activation In Alcoholic Liver Disease In Mice, David Tornai, Istvan Furi, Zu T. Shen, Alexander B. Sigalov, Sahin Coban, Gyongyi Szabo

Gyongyi Szabo

Alcoholic liver disease (ALD) is characterized by macrophage and neutrophil leukocyte recruitment and activation in the liver. Damage- and pathogen-associated molecular patterns contribute to a self-perpetuating proinflammatory state in ALD. Triggering receptor expressed on myeloid cells 1 (TREM-1) is a surface receptor that amplifies inflammation induced by toll-like receptors (TLRs) and is expressed on neutrophils and monocytes/macrophages. We hypothesized that TREM-1 signaling contributes to proinflammatory pathway activation in ALD. Using an in vivo ALD model in mice, we tested the effects of ligand-independent TREM-1 inhibitory peptides that were formulated into human high-density lipoprotein (HDL)-mimicking complexes GF9-HDL and GA/E31-HDL. As revealed …


A Novel Human Radixin Peptide Inhibits Hepatitis C Virus Infection At The Level Of Cell Entry, Terence Bukong, Karen Kodys, Gyongyi Szabo Jun 2015

A Novel Human Radixin Peptide Inhibits Hepatitis C Virus Infection At The Level Of Cell Entry, Terence Bukong, Karen Kodys, Gyongyi Szabo

Gyongyi Szabo

Hepatitis C virus infection of hepatocytes is a multistep process involving the interaction between viral and host cell molecules. Recently, we identified ezrin-moesin-radixin proteins and spleen tyrosine kinase (SYK) as important host therapeutic targets for HCV treatment development. Previously, an ezrin hinge region peptide (Hep1) has been shown to exert anti-HCV properties in vivo, though its mechanism of action remains limited. In search of potential novel inhibitors of HCV infection and their functional mechanism we analyzed the anti-HCV properties of different human derived radixin peptides. Sixteen different radixin peptides were derived, synthesized and tested. Real-time quantitative PCR, cell toxicity assay, …


Detection Of Igg4-Specific Autoantibodies In Rheumatoid Arthritis Serum Samples, Azra Borogovac, Youmna Lahoud, Janice Weaver, Sheldon M. Cooper, Mercedes Rincon, Jonathan Kay, Ellen M. Gravallese May 2015

Detection Of Igg4-Specific Autoantibodies In Rheumatoid Arthritis Serum Samples, Azra Borogovac, Youmna Lahoud, Janice Weaver, Sheldon M. Cooper, Mercedes Rincon, Jonathan Kay, Ellen M. Gravallese

Ellen M. Gravallese

Background: Rheumatoid arthritis (RA) is a chronic multi-system autoimmune disease characterized by inflammatory synovitis. Autoantibodies such as rheumatoid factor (RF) and anti-citrullinated protein antibodies (ACPA) have been implicated in the pathogenesis of RA, and are currently important criteria for diagnosis within the 2010 American College of Rheumatology (ACR)/European League Against Rheumatism (EULAR) classification criteria.1 Yet, many patients diagnosed with RA do not have measurable circulating ACPA or RF which may result in delayed diagnosis and treatment. After IgG1, IgG4 is the second most predominant isotype among ACPA and RF; however it is not detected in currently available diagnostic assays. Recent …


Detection Of Igg4-Specific Autoantibodies In Rheumatoid Arthritis Serum Samples, Azra Borogovac, Youmna Lahoud, Janice Weaver, Sheldon M. Cooper, Mercedes Rincon, Jonathan Kay, Ellen M. Gravallese May 2015

Detection Of Igg4-Specific Autoantibodies In Rheumatoid Arthritis Serum Samples, Azra Borogovac, Youmna Lahoud, Janice Weaver, Sheldon M. Cooper, Mercedes Rincon, Jonathan Kay, Ellen M. Gravallese

Jonathan Kay

Background: Rheumatoid arthritis (RA) is a chronic multi-system autoimmune disease characterized by inflammatory synovitis. Autoantibodies such as rheumatoid factor (RF) and anti-citrullinated protein antibodies (ACPA) have been implicated in the pathogenesis of RA, and are currently important criteria for diagnosis within the 2010 American College of Rheumatology (ACR)/European League Against Rheumatism (EULAR) classification criteria.1 Yet, many patients diagnosed with RA do not have measurable circulating ACPA or RF which may result in delayed diagnosis and treatment. After IgG1, IgG4 is the second most predominant isotype among ACPA and RF; however it is not detected in currently available diagnostic assays. Recent …


Nonenzymatic Glycosylation Of Erythrocyte Membrane Proteins. Relevance To Diabetes, J A. Miller, Ellen M. Gravallese, H F. Bunn Apr 2015

Nonenzymatic Glycosylation Of Erythrocyte Membrane Proteins. Relevance To Diabetes, J A. Miller, Ellen M. Gravallese, H F. Bunn

Ellen M. Gravallese

Nonenzymatic glycosylation of proteins of the erythrocyte membrane was determined by incubating erythrocyte ghosts with [3H]borohydride. The incorporation of tritium into protein provides a reliable assay of ketoamine linkages. The membrane proteins from 18 patients with diabetes incorporated twice as much radioactivity as membrane proteins from normal erythrocytes. After acid hydrolysis, amino acid analysis showed that the majority of radioactivity was localized to glucosyllysine. Autoradiograms showed that all of the major proteins of the erythrocyte membrane, separated by electrophoresis on sodium dodecyl sulfate gels, contained ketoamine linkages. No protein bands in either normal or diabetic erythrocytes showed significant preferential labeling. …


Dual Engagement Of The Nlrp3 And Aim2 Inflammasomes By Plasmodium-Derived Hemozoin And Dna During Malaria, Parisa Kalantari, Rosane B. Deoliveira, Jennie Chan, Yolanda Corbett, Vijay A. K. Rathinam, Andrea Stutz, Eicke Latz, Ricardo T. Gazzinelli, Douglas T. Golenbock, Katherine A. Fitzgerald Dec 2014

Dual Engagement Of The Nlrp3 And Aim2 Inflammasomes By Plasmodium-Derived Hemozoin And Dna During Malaria, Parisa Kalantari, Rosane B. Deoliveira, Jennie Chan, Yolanda Corbett, Vijay A. K. Rathinam, Andrea Stutz, Eicke Latz, Ricardo T. Gazzinelli, Douglas T. Golenbock, Katherine A. Fitzgerald

Katherine A. Fitzgerald

Hemozoin (Hz) is the crystalline detoxification product of hemoglobin in Plasmodium-infected erythrocytes. We previously proposed that Hz can carry plasmodial DNA into a subcellular compartment that is accessible to Toll-like receptor 9 (TLR9), inducing an inflammatory signal. Hz also activates the NLRP3 inflammasome in primed cells. We found that Hz appears to colocalize with DNA in infected erythrocytes, even before RBC rupture or phagolysosomal digestion. Using synthetic Hz coated in vitro with plasmodial genomic DNA (gDNA) or CpG oligodeoxynucleotides, we observed that DNA-complexed Hz induced TLR9 translocation, providing a priming and an activation signal for inflammasomes. After phagocytosis, Hz and …


Regulated Splicing Of The Alpha6 Integrin Cytoplasmic Domain Determines The Fate Of Breast Cancer Stem Cells, Hira Lal Goel, Tatiana Gritsko, Bryan Pursell, Cheng Chang, Leonard D. Shultz, Dale L. Greiner, Jens Henrik Norum, Rune Toftgard, Leslie M. Shaw, Arthur M. Mercurio Nov 2014

Regulated Splicing Of The Alpha6 Integrin Cytoplasmic Domain Determines The Fate Of Breast Cancer Stem Cells, Hira Lal Goel, Tatiana Gritsko, Bryan Pursell, Cheng Chang, Leonard D. Shultz, Dale L. Greiner, Jens Henrik Norum, Rune Toftgard, Leslie M. Shaw, Arthur M. Mercurio

Arthur M. Mercurio

Although the alpha6beta1 integrin has been implicated in the function of breast and other cancer stem cells (CSCs), little is known about its regulation and relationship to mechanisms involved in the genesis of CSCs. We report that a CD44(high)/CD24(low) population, enriched for CSCs, is comprised of distinct epithelial and mesenchymal populations that differ in expression of the two alpha6 cytoplasmic domain splice variants: alpha6A and alpha6B. alpha6Bbeta1 expression defines the mesenchymal population and is necessary for CSC function, a function that cannot be executed by alpha6A integrins. The generation of alpha6Bbeta1 is tightly controlled and occurs as a consequence of …


Identification Of A Human Monoclonal Antibody To Replace Equine Diphtheria Anti-Toxin For The Treatment Of Diphtheria, Leila M. Sevigny, Brian J. Booth, Kirk J. Rowley, Brett A. Leav, Peter S. Cheslock, Kerry A. Garrity, Susan Sloan, Gregory J. Babcock, William D. Thomas, Mark Klempner, Yang Wang Aug 2013

Identification Of A Human Monoclonal Antibody To Replace Equine Diphtheria Anti-Toxin For The Treatment Of Diphtheria, Leila M. Sevigny, Brian J. Booth, Kirk J. Rowley, Brett A. Leav, Peter S. Cheslock, Kerry A. Garrity, Susan Sloan, Gregory J. Babcock, William D. Thomas, Mark Klempner, Yang Wang

William D Thomas Jr

Diphtheria anti-toxin (DAT) has been used to treat Corynebacterium diphtheriae infection for over one hundred years. While the global incidence of diphtheria has declined in the 20th century, the disease remains endemic in many parts of the world and significant outbreaks still occur. Diphtheria anti-toxin is an equine polyclonal antibody with considerable side effects that is in critically short supply globally. A safer, more readily available alternative to DAT would be desirable. In the current study, we cloned human monoclonal antibodies (HuMabs) directly from antibody secreting cells of human volunteers immunized with Td vaccine. We isolated a diverse panel of …


The Use Of A Ditopic Gd(Iii) Paramagnetic Probe For Investigating Α-Bungarotoxin Surface Accessibility, Andrea Bernini, Ottavia Spiga, Vincenzo Venditti, Filippo Prischi, Mauro Botta, Gianluca Croce, Angela Pui-Ling Tong, Wing-Talk Wong, Neri Niccolai Jan 2012

The Use Of A Ditopic Gd(Iii) Paramagnetic Probe For Investigating Α-Bungarotoxin Surface Accessibility, Andrea Bernini, Ottavia Spiga, Vincenzo Venditti, Filippo Prischi, Mauro Botta, Gianluca Croce, Angela Pui-Ling Tong, Wing-Talk Wong, Neri Niccolai

Vincenzo Venditti

Protein surface accessibility is a critical parameter which drives all intermolecular interaction processes. In this respect a big deal of information has been derived by analyzing paramagnetic perturbation profiles obtained from NMR protein spectra, particularly in the case that the effects due to different soluble paramagnets can be compared. Here Gd2L7, a neutral ditopic paramagnetic NMR probe, has been characterized in terms of structure and relaxivity and its paramagnetic perturbations on α-bungarotoxin CαH signals in 1H–13C HSQC (heteronuclear single quantum coherence) spectra have been analyzed. Then, these signal attenuations have been compared with the ones previously obtained in the presence …


An Efficient Protocol For Incorporation Of An Unnatural Amino Acid In Perdeuterated Recombinant Proteins Using Glucose-Based Media, Vincenzo Venditti, Nicolas L. Fawzi, G. Marius Clore Jan 2012

An Efficient Protocol For Incorporation Of An Unnatural Amino Acid In Perdeuterated Recombinant Proteins Using Glucose-Based Media, Vincenzo Venditti, Nicolas L. Fawzi, G. Marius Clore

Vincenzo Venditti

The in vivo incorporation of unnatural amino acids into proteins is a well-established technique requiring an orthogonal tRNA/aminoacyl-tRNA synthetase pair specific for the unnatural amino acid that is incorporated at a position encoded by a TAG amber codon. Although this technology provides unique opportunities to engineer protein structures, poor protein yields are usually obtained in deuterated media, hampering its application in the protein NMR field. Here, we describe a novel protocol for incorporating unnatural amino acids into fully deuterated proteins using glucose-based media (which are relevant to the production, for example, of amino acid-specific methyl-labeled proteins used in the study …


Automated Sequence- And Stereo-Specific Assignment Of Methyl-Labeled Proteins By Paramagnetic Relaxation And Methyl–Methyl Nuclear Overhauser Enhancement Spectroscopy, Vincenzo Venditti, Nicolas L. Fawzi, G. Marius Clore Jan 2011

Automated Sequence- And Stereo-Specific Assignment Of Methyl-Labeled Proteins By Paramagnetic Relaxation And Methyl–Methyl Nuclear Overhauser Enhancement Spectroscopy, Vincenzo Venditti, Nicolas L. Fawzi, G. Marius Clore

Vincenzo Venditti

Methyl-transverse relaxation optimized spectroscopy is rapidly becoming the preferred NMR technique for probing structure and dynamics of very large proteins up to ~1 MDa in molecular size. Data interpretation, however, necessitates assignment of methyl groups which still presents a very challenging and time-consuming process. Here we demonstrate that, in combination with a known 3D structure, paramagnetic relaxation enhancement (PRE), induced by nitroxide spin-labels incorporated at only a few surface-exposed engineered cysteines, provides fast, straightforward and robust access to methyl group resonance assignments, including stereoassignments for the methyl groups of leucine and valine. Neither prior assignments, including backbone assignments, for the …


A Structurally Driven Analysis Of Thiol Reactivity In Mammalian Albumins, Ottavia Spiga, Domenico Summa, Simone Cirri, Andrea Bernini, Vincenzo Venditti, Matteo De Chiara, Raffaella Priora, Simona Frosail, Antonios Margaritis, Danila Di Giuseppe, Paolo Di Simplicio, Neri Niccolai Jan 2011

A Structurally Driven Analysis Of Thiol Reactivity In Mammalian Albumins, Ottavia Spiga, Domenico Summa, Simone Cirri, Andrea Bernini, Vincenzo Venditti, Matteo De Chiara, Raffaella Priora, Simona Frosail, Antonios Margaritis, Danila Di Giuseppe, Paolo Di Simplicio, Neri Niccolai

Vincenzo Venditti

Understanding the structural basis of protein redox activity is still an open question. Hence, by using a structural genomics approach, different albumins have been chosen to correlate protein structural features with the corresponding reaction rates of thiol exchange between albumin and disulfide DTNB. Predicted structures of rat, porcine, and bovine albumins have been compared with the experimentally derived human albumin. High structural similarity among these four albumins can be observed, in spite of their markedly different reactivity with DTNB. Sequence alignments offered preliminary hints on the contributions of sequence-specific local environments modulating albumin reactivity. Molecular dynamics simulations performed on experimental …