scholarly journals The Structure and Immune Regulatory Implications of the Ubiquitin-Like Tandem Domain Within an Avian 2’-5’ Oligoadenylate Synthetase-Like Protein

2022 ◽  
Vol 12 ◽  
Author(s):  
Justin D. Shepard ◽  
Brendan T. Freitas ◽  
Sergio E. Rodriguez ◽  
Florine E. M. Scholte ◽  
Kailee Baker ◽  
...  
Keyword(s):  
Immune Response ◽  
Structural Characteristics ◽  
Viral Proteins ◽  
Post Translational Modification ◽  
Oligoadenylate Synthetase ◽  
Protein Protein Interaction ◽  
Robust Immune Response ◽  
Enhanced Production ◽  
C Terminus ◽  
In Series

Post-translational modification of host and viral proteins by ubiquitin and ubiquitin-like proteins plays a key role in a host’s ability to mount an effective immune response. Avian species lack a ubiquitin-like protein found in mammals and other non-avian reptiles; interferon stimulated gene product 15 (ISG15). ISG15 serves as a messenger molecule and can be conjugated to both host and viral proteins leading them to be stabilized, degraded, or sequestered. Structurally, ISG15 is comprised of a tandem ubiquitin-like domain (Ubl), which serves as the motif for post-translational modification. The 2’-5’ oligoadenylate synthetase-like proteins (OASL) also encode two Ubl domains in series near its C-terminus which binds OASL to retinoic acid inducible gene-I (RIG-I). This protein-protein interaction increases the sensitivity of RIG-I and results in an enhanced production of type 1 interferons and a robust immune response. Unlike human and other mammalian OASL homologues, avian OASLs terminate their tandem Ubl domains with the same LRLRGG motif found in ubiquitin and ISG15, a motif required for their conjugation to proteins. Chickens, however, lack RIG-I, raising the question of structural and functional characteristics of chicken OASL (chOASL). By investigating chOASL, the evolutionary history of viruses with deubiquitinases can be explored and drivers of species specificity for these viruses may be uncovered. Here we show that the chOASL tandem Ubl domains shares structural characteristics with mammalian ISG15, and that chOASL can oligomerize and conjugate to itself. In addition, the ISG15-like features of avian OASLs and how they impact interactions with viral deubiquitinases and deISGylases are explored.

scholarly journals In silico characterization of GmSOS1 provides a comprehensive understanding for its role in soybean salt tolerance

2020 ◽  
Author(s):  
Zhi-Chao Mei ◽  
Ling-Yan Yang ◽  
Zhi-Min Liu ◽  
Qi-Li Tang ◽  
Xin-Zhao Hou ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Salt Tolerance ◽  
In Silico ◽  
Structural Characteristics ◽  
Interaction Network ◽  
Regulation Mechanism ◽  
Post Translational Modification ◽  
Protein Protein Interaction ◽  
Plant Salt Tolerance ◽  
Primary Basis

AbstractPlant SOS1 encodes plasma membrane Na+/H+ antiporter, which helps in the exclusion of Na+ and improves plant salt tolerance. However, detailed studies of SOS1 in the important oil crop, soybean (Glycine max), are still lacking. In the present study, we carried out a comprehensive in silico analysis of SOS1 in soybean. Referring to the analysis of physicochemical properties and structural characteristics, the GmSOS1 is an acidic protein with instability and hydrophobicity. Subcellular localization of GmSOS1 supports the presumption that GmSOS1 is a plasma membrane Na+/H+ antiporter. Post-translational modification site prediction indicates 4 amino acids that may be phosphorylated. Further, the protein-protein interaction network and co-functional network signify the potential role of GmSOS1 in salt stress tolerance. Although the interaction between GmSOS1 and GmHKT1 remains elusive, some of the intermediary signaling components of SOS pathway in soybean have been predicted. In addition, in silico expression analysis based on transcriptome datasets using publicly available database revealed that GmSOS1 was differentially expressed in tissues and different times. Due to the analysis of its regulation mechanism, we found transcription factors such as WRKY and ERF as well as three miRNAs can regulate the expression of GmSOS1. Phylogenetic analysis using the homologous amino acid sequence of SOS1s from 26 species was performed to study the conserved motifs among these SOS1 members. Overall, we provide an extensive analysis of the GmSOS1 and it promises the primary basis for the study in development and response to salt tolerance.

scholarly journals Effect of O-Antigen Chain Length Regulation on the Immunogenicity of Shigella and Salmonella Generalized Modules for Membrane Antigens (GMMA)

2021 ◽  
Vol 22 (3) ◽  
pp. 1309
Author(s):  
Gianmarco Gasperini ◽  
Maria Michelina Raso ◽  
Vanessa Arato ◽  
Maria Grazia Aruta ◽  
Paola Cescutti ◽  
...  
Keyword(s):  
Immune Response ◽  
Structural Characteristics ◽  
Antigen Delivery ◽  
Critical Quality Attributes ◽  
O Antigen ◽  
Alternative Approach ◽  
Length Regulation ◽  
Membrane Antigens ◽  
Glycoconjugate Vaccines ◽  
Work Supports

Recently, generalized modules for membrane antigens (GMMA) technology has been proposed as an alternative approach to traditional glycoconjugate vaccines for O-antigen delivery. Saccharide length is a well-known parameter that can impact the immune response induced by glycoconjugates both in terms of magnitude and quality. However, the criticality of O-antigen length on the immune response induced by GMMA-based vaccines has not been fully elucidated. Here, Shigella and Salmonella GMMA-producing strains were further mutated in order to display homogeneous polysaccharide populations of different sizes on a GMMA surface. Resulting GMMA were compared in mice immunization studies. Athymic nude mice were also used to investigate the involvement of T-cells in the immune response elicited. In contrast with what has been reported for traditional glycoconjugate vaccines and independent of the pathogen and the sugar structural characteristics, O-antigen length did not result in being a critical parameter for GMMA immunogenicity. This work supports the identification of critical quality attributes to optimize GMMA vaccine design and improve vaccine efficacy and gives insights on the nature of the immune response induced by GMMA.

scholarly journals Comparison of two Turnip mosaic virus P1 proteins in their ability to co-localize with the Arabidopsis thaliana G3BP-2 protein

Virus Genes ◽  
2021 ◽  
Vol 57 (2) ◽  
pp. 233-237
Author(s):  
Hendrik Reuper ◽  
Björn Krenz
Keyword(s):  
Arabidopsis Thaliana ◽  
Mosaic Virus ◽  
Specific Interaction ◽  
Viral Proteins ◽  
Turnip Mosaic Virus ◽  
Stress Conditions ◽  
C Terminus ◽  
Positive Sense ◽  
Key Factor ◽  
Large Host

AbstractTurnip mosaic virus (TuMV), belonging to the genus Potyvirus (family Potyviridae), has a large host range and consists of a single-stranded positive sense RNA genome encoding 12 proteins, including the P1 protease. This protein which is separated from the polyprotein by cis cleavage at its respective C-terminus, has been attributed with different functions during potyviral infection of plants. P1 of Turnip mosaic virus (P1-TuMV) harbors an FGSF-motif and FGSL-motif at its N-terminus. This motif is predicted to be a binding site for the host Ras GTPase-activating protein-binding protein (G3BP), which is a key factor for stress granule (SG) formation in mammalian systems and often targeted by viruses to inhibit SG formation. We therefore hypothesized that P1-TuMV might interact with G3BP to control and regulate plant SGs to optimize cellular conditions for the production of viral proteins. Here, we analyzed the co-localization of the Arabidopsis thaliana G3BP-2 with the P1 of two TuMV isolates, namely UK 1 and DEU 2. Surprisingly, P1-TuMV-DEU 2 co-localized with AtG3BP-2 under abiotic stress conditions, whereas P1-TuMV-UK 1 did not. AtG3BP-2::RFP showed strong SGs formation after stress, while P1-UK 1::eGFP maintained a chloroplastic signal under stress conditions, the signal of P1-DEU 2::eGFP co-localized with that of AtG3BP-2::RFP. This indicates a specific interaction between P1-DEU 2 and the AtG3BP family which is not solely based on the canonical interaction motifs.

scholarly journals Role of Host-Mediated Post-Translational Modifications (PTMs) in RNA Virus Pathogenesis

2020 ◽  
Vol 22 (1) ◽  
pp. 323
Author(s):  
Ramesh Kumar ◽  
Divya Mehta ◽  
Nimisha Mishra ◽  
Debasis Nayak ◽  
Sujatha Sunil
Keyword(s):  
Rna Virus ◽  
Viral Proteins ◽  
Post Translational Modification ◽  
Host Proteins ◽  
Viral Protein Synthesis ◽  
Post Translational Modifications ◽  
Small Proteins ◽  
Cellular Machinery ◽  
Chemical Groups

Being opportunistic intracellular pathogens, viruses are dependent on the host for their replication. They hijack host cellular machinery for their replication and survival by targeting crucial cellular physiological pathways, including transcription, translation, immune pathways, and apoptosis. Immediately after translation, the host and viral proteins undergo a process called post-translational modification (PTM). PTMs of proteins involves the attachment of small proteins, carbohydrates/lipids, or chemical groups to the proteins and are crucial for the proteins’ functioning. During viral infection, host proteins utilize PTMs to control the virus replication, using strategies like activating immune response pathways, inhibiting viral protein synthesis, and ultimately eliminating the virus from the host. PTM of viral proteins increases solubility, enhances antigenicity and virulence properties. However, RNA viruses are devoid of enzymes capable of introducing PTMs to their proteins. Hence, they utilize the host PTM machinery to promote their survival. Proteins from viruses belonging to the family: Togaviridae, Flaviviridae, Retroviridae, and Coronaviridae such as chikungunya, dengue, zika, HIV, and coronavirus are a few that are well-known to be modified. This review discusses various host and virus-mediated PTMs that play a role in the outcome during the infection.

scholarly journals Cascading from SARS-CoV-2 to Parkinson’s Disease through Protein-Protein Interactions

Viruses ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 897
Author(s):  
Ernesto Estrada
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Protein Interactions ◽  
Molecular Level ◽  
Direct Consequence ◽  
Viral Proteins ◽  
Clinical Findings ◽  
Post Translational Modification ◽  
Host Proteins ◽  
Bioinformatic Tools

Extensive extrapulmonary damages in a dozen of organs/systems, including the central nervous system (CNS), are reported in patients of the coronavirus disease 2019 (COVID-19). Three cases of Parkinson’s disease (PD) have been reported as a direct consequence of COVID-19. In spite of the scarce data for establishing a definitive link between COVID-19 and PD, some hypotheses have been proposed to explain the cases reported. They, however, do not fit well with the clinical findings reported for COVID-19 patients, in general, and for the PD cases reported, in particular. Given the importance of this potential connection, we present here a molecular-level mechanistic hypothesis that explains well these findings and will serve to explore the potential CNS damage in COVID-19 patients. The model explaining the cascade effects from COVID-19 to CNS is developed by using bioinformatic tools. It includes the post-translational modification of host proteins in the lungs by viral proteins, the transport of modified host proteins via exosomes out the lungs, and the disruption of protein-protein interaction in the CNS by these modified host proteins. Our hypothesis is supported by finding 44 proteins significantly expressed in the CNS which are associated with PD and whose interactions can be perturbed by 24 host proteins significantly expressed in the lungs. These 24 perturbators are found to interact with viral proteins and to form part of the cargoes of exosomes in human tissues. The joint set of perturbators and PD-vulnerable proteins form a tightly connected network with significantly more connections than expected by selecting a random cluster of proteins of similar size from the human proteome. The molecular-level mechanistic hypothesis presented here provides several routes for the cascading of effects from the lungs of COVID-19 patients to PD. In particular, the disruption of autophagy/ubiquitination processes appears as an important mechanism that triggers the generation of large amounts of exosomes containing perturbators in their cargo, which would insult several PD-vulnerable proteins, potentially triggering Parkinsonism in COVID-19 patients.

scholarly journals Development of SARS-CoV-2 Specific IgG and Virus-Neutralizing Antibodies after Infection with Variants of Concern or Vaccination

Vaccines ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 700
Author(s):  
Franziska Neumann ◽  
Ruben Rose ◽  
Janine Römpke ◽  
Olaf Grobe ◽  
Thomas Lorentz ◽  
...  
Keyword(s):  
Immune Response ◽  
Receptor Binding ◽  
Neutralizing Antibodies ◽  
Neutralization Test ◽  
Vaccine Dose ◽  
High Avidity ◽  
Receptor Binding Domain ◽  
Robust Immune Response ◽  
Specific Igg ◽  
Nucleoprotein N

The humoral immunity after SARS-CoV-2 infection or vaccination was examined. Convalescent sera after infection with variants of concern (VOCs: B.1.1.7, n = 10; B.1.351, n = 1) and sera from 100 vaccinees (Pfizer/BioNTech, BNT162b2, n = 33; Moderna, mRNA-1273, n = 11; AstraZeneca, ChAdOx1 nCoV-19/AZD1222, n = 56) were tested for the presence of immunoglobulin G (IgG) directed against the viral spike (S)-protein, its receptor-binding domain (RBD), the nucleoprotein (N) and for virus-neutralizing antibodies (VNA). For the latter, surrogate assays (sVNT) and a Vero-cell based neutralization test (cVNT) were used. Maturity of IgG was determined by measuring the avidity in an immunoblot (IB). Past VOC infection resulted in a broad reactivity of anti-S IgG (100%), anti-RBD IgG (100%), and anti-N IgG (91%), while latter were absent in 99% of vaccinees. Starting approximately two weeks after the first vaccine dose, anti-S IgG (75–100%) and particularly anti-RBD IgG (98–100%) were detectable. After the second dose, their titers increased and were higher than in the convalescents. The sVNT showed evidence of VNA in 91% of convalescents and in 80–100%/100% after first/second vaccine dose, respectively. After the second dose, an increase in VNA titer and IgGs of high avidity were demonstrated by cVNT and IB, respectively. Re-vaccination contributes to a more robust immune response.

scholarly journals Modulation of Antigen Display on PapMV Nanoparticles Influences Its Immunogenicity

Vaccines ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 33
Author(s):  
Marie-Eve Laliberté-Gagné ◽  
Marilène Bolduc ◽  
Caroline Garneau ◽  
Santa-Mariela Olivera-Ugarte ◽  
Pierre Savard ◽  
...  
Keyword(s):  
Immune Response ◽  
Influenza A ◽  
Matrix Protein ◽  
Cell Epitope ◽  
Vaccine Antigen ◽  
Vaccine Platform ◽  
Peptide Antigens ◽  
C Terminus ◽  
The Impact ◽  
Stimulation Of

Background: The papaya mosaic virus (PapMV) vaccine platform is a rod-shaped nanoparticle made of the recombinant PapMV coat protein (CP) self-assembled around a noncoding single-stranded RNA (ssRNA) template. The PapMV nanoparticle induces innate immunity through stimulation of the Toll-like receptors (TLR) 7 and 8. The display of the vaccine antigen at the surface of the nanoparticle, associated with the co-stimulation signal via TLR7/8, ensures a strong stimulation of the immune response, which is ideal for the development of candidate vaccines. In this study, we assess the impact of where the peptide antigen is fused, whether at the surface or at the extremities of the nanoparticles, on the immune response directed to that antigen. Methods: Two different peptides from influenza A virus were used as model antigens. The conserved M2e peptide, derived from the matrix protein 2 was chosen as the B-cell epitope, and a peptide derived from the nucleocapsid was chosen as the cytotoxic T lymphocytes (CTL) epitope. These peptides were coupled at two different positions on the PapMV CP, the N- (PapMV-N) or the C-terminus (PapMV-C), using the transpeptidase activity of Sortase A (SrtA). The immune responses, both humoral and CD8+ T-cell-mediated, directed to the peptide antigens in the two different fusion contexts were analyzed and compared. The impact of coupling density at the surface of the nanoparticle was also investigated. Conclusions: The results demonstrate that coupling of the peptide antigens at the N-terminus (PapMV-N) of the PapMV CP led to an enhanced immune response to the coupled peptide antigens as compared to coupling to the C-terminus. The difference between the two vaccine platforms is linked to the enhanced capacity of the PapMV-N vaccine platform to stimulate TLR7/8. We also demonstrated that the strength of the immune response increases with the density of coupling at the surface of the nanoparticles.

High content screening and computational prediction reveal viral genes that suppress innate immune response

2021 ◽  
Author(s):  
Tai L Ng ◽  
Erika J Olson ◽  
Tae Yeon Yoo ◽  
H. Sloane Weiss ◽  
Yukiye Koide ◽  
...  
Keyword(s):  
Immune Response ◽  
Innate Immune Response ◽  
Nuclear Transport ◽  
Computational Prediction ◽  
Viral Proteins ◽  
Innate Immune ◽  
Type I ◽  
Viral Genes ◽  
Genes Encoding

Suppression of the host innate immune response is a critical aspect of viral replication. Upon infection, viruses may introduce one or more proteins that inhibit key immune pathways, such as the type I interferon pathway. However, the ability to predict and evaluate viral protein bioactivity on targeted pathways remains challenging and is typically done on a single virus/gene basis. Here, we present a medium-throughput high-content cell-based assay to reveal the immunosuppressive effects of viral proteins. To test the predictive power of our approach, we developed a library of 800 genes encoding known, predicted, and uncharacterized human viral genes. We find that previously known immune suppressors from numerous viral families such as Picornaviridae and Flaviviridae recorded positive responses. These include a number of viral proteases for which we further confirmed that innate immune suppression depends on protease activity. A class of predicted inhibitors encoded by Rhabdoviridae viruses was demonstrated to block nuclear transport, and several previously uncharacterized proteins from uncultivated viruses were shown to inhibit nuclear transport of the transcription factors NF-kB and IRF3. We propose that this pathway-based assay, together with early sequencing, gene synthesis, and viral infection studies, could partly serve as the basis for rapid in vitro characterization of novel viral proteins.

scholarly journals Phagocytes from Mice Lacking the Sts Phosphatases Have an Enhanced Antifungal Response to Candida albicans

mBio ◽  
2018 ◽  
Vol 9 (4) ◽  
Author(s):  
David Frank ◽  
Shamoon Naseem ◽  
Gian Luigi Russo ◽  
Cindy Li ◽  
Kaustubh Parashar ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Immune Response ◽  
Candida Albicans ◽  
Tyrosine Kinase ◽  
Critical Role ◽  
Inflammasome Activation ◽  
Wild Type ◽  
Content Type ◽  
Enhanced Production ◽  
Immunological Mechanisms

ABSTRACT Mice lacking expression of the homologous phosphatases Sts-1 and Sts-2 (Sts−/− mice) are resistant to disseminated candidiasis caused by the fungal pathogen Candida albicans. To better understand the immunological mechanisms underlying the enhanced resistance of Sts−/− mice, we examined the kinetics of fungal clearance at early time points. In contrast to the rapid C. albicans growth seen in normal kidneys during the first 24 h postinfection, we observed a reduction in kidney fungal CFU within Sts−/− mice beginning at 12 to 18 h postinfection. This corresponds to the time period when large numbers of innate leukocytes enter the renal environment to counter the infection. Because phagocytes of the innate immune system are important for host protection against pathogenic fungi, we evaluated responses of bone marrow leukocytes. Relative to wild-type cells, Sts−/− marrow monocytes and bone marrow-derived dendritic cells (BMDCs) displayed a heightened ability to inhibit C. albicans growth ex vivo. This correlated with significantly enhanced production of reactive oxygen species (ROS) by Sts−/− BMDCs downstream of Dectin-1, a C-type lectin receptor that plays a critical role in stimulating host responses to fungi. We observed no visible differences in the responses of other antifungal effector pathways, including cytokine production and inflammasome activation, despite enhanced activation of the Syk tyrosine kinase downstream of Dectin-1 in Sts−/− cells. Our results highlight a novel mechanism regulating the immune response to fungal infections. Further understanding of this regulatory pathway could aid the development of therapeutic approaches to enhance protection against invasive candidiasis. IMPORTANCE Systemic candidiasis caused by fungal Candida species is becoming an increasingly serious medical problem for which current treatment is inadequate. Recently, the Sts phosphatases were established as key regulators of the host antifungal immune response. In particular, genetic inactivation of Sts significantly enhanced survival of mice infected intravenously with Candida albicans. The Sts−/− in vivo resistance phenotype is associated with reduced fungal burden and an absence of inflammatory lesions. To understand the underlying mechanisms, we studied phagocyte responses. Here, we demonstrate that Sts−/− phagocytes have heightened responsiveness to C. albicans challenge relative to wild-type cells. Our data indicate the Sts proteins negatively regulate phagocyte activation via regulating selective elements of the Dectin-1–Syk tyrosine kinase signaling axis. These results suggest that phagocytes lacking Sts respond to fungal challenge more effectively and that this enhanced responsiveness partially underlies the profound resistance of Sts−/− mice to systemic fungal challenge.

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