scholarly journals Deaminase-Independent Mode of Antiretroviral Action in Human and Mouse APOBEC3 Proteins

2020 ◽  
Vol 8 (12) ◽  
pp. 1976
Author(s):  
Yoshiyuki Hakata ◽  
Masaaki Miyazawa
Keyword(s):  
Molecular Mechanisms ◽  
Restriction Factors ◽  
Mrna Editing ◽  
Antiviral Function ◽  
Apobec3 Proteins ◽  
And Function ◽  
Editing Enzyme ◽  
Dependent Pathway ◽  
Independent Mode ◽  
Human Apobec3g

Apolipoprotein B mRNA editing enzyme, catalytic polypeptide-like 3 (APOBEC3) proteins (APOBEC3s) are deaminases that convert cytosines to uracils predominantly on a single-stranded DNA, and function as intrinsic restriction factors in the innate immune system to suppress replication of viruses (including retroviruses) and movement of retrotransposons. Enzymatic activity is supposed to be essential for the APOBEC3 antiviral function. However, it is not the only way that APOBEC3s exert their biological function. Since the discovery of human APOBEC3G as a restriction factor for HIV-1, the deaminase-independent mode of action has been observed. At present, it is apparent that both the deaminase-dependent and -independent pathways are tightly involved not only in combating viruses but also in human tumorigenesis. Although the deaminase-dependent pathway has been extensively characterized so far, understanding of the deaminase-independent pathway remains immature. Here, we review existing knowledge regarding the deaminase-independent antiretroviral functions of APOBEC3s and their molecular mechanisms. We also discuss the possible unidentified molecular mechanism for the deaminase-independent antiretroviral function mediated by mouse APOBEC3.

scholarly journals Perturbation of biogenesis and targeting of Epstein–Barr virus-encoded miR-BART3 microRNA by adenosine-to-inosine editing

2013 ◽  
Vol 94 (12) ◽  
pp. 2739-2744 ◽  
Author(s):  
Ting Lei ◽  
Kit-San Yuen ◽  
Sai Wah Tsao ◽  
Honglin Chen ◽  
Kin-Hang Kok ◽  
...  
Keyword(s):  
Nasopharyngeal Carcinoma ◽  
Epstein Barr Virus ◽  
Carcinoma Cells ◽  
Seed Region ◽  
Mrna Editing ◽  
Barr Virus ◽  
Mature Micrornas ◽  
Epstein Barr ◽  
And Function ◽  
Editing Enzyme

Epstein–Barr virus (EBV) encodes at least 44 mature microRNAs (miRNAs), some of which are abundantly expressed in nasopharyngeal carcinoma cells. EBV-encoded miR-BART6 miRNA is known to undergo adenosine-to-inosine (A-to-I) RNA editing, which impacts on processing and function. Whether additional EBV miRNAs might be A-to-I edited remains to be determined. In this study, we have reported on A-to-I editing of EBV miR-BART3. The A-to-I editing enzyme was expressed abundantly in EBV-infected epithelial carcinoma cells. pri-miR-BART3 was found to be edited at four sites in these cells and in nasopharyngeal carcinoma samples. Whereas editing of the second site located within the seed region prevented the targeting of DICE1 mRNA, editing of the third site effectively crippled the biogenesis of mature miR-BART3. Thus, A-to-I editing perturbs biogenesis and targeting of miR-BART3 and may contribute to its differential expression and function in EBV-infected epithelial cells.

scholarly journals Human APOBEC3G-Mediated Editing Can Promote HIV-1 Sequence Diversification and Accelerate Adaptation to Selective Pressure

2010 ◽  
Vol 84 (19) ◽  
pp. 10402-10405 ◽  
Author(s):  
Eun-Young Kim ◽  
Tanmoy Bhattacharya ◽  
Kevin Kunstman ◽  
Peter Swantek ◽  
Fransje A. Koning ◽  
...  
Keyword(s):  
Resistance Mutations ◽  
Mrna Editing ◽  
Human Apolipoprotein ◽  
Immunodeficiency Virus ◽  
Editing Enzyme ◽  
The Impact ◽  
Hiv 1 ◽  
Human Apobec3g

ABSTRACT Human apolipoprotein B mRNA-editing enzyme catalytic polypeptide-like 3G (APOBEC3G, hereinafter referred to as A3G) is an innate virus restriction factor that inhibits human immunodeficiency virus type 1 (HIV-1) replication and induces excessive deamination of cytidine residues in nascent reverse transcripts. To test the hypothesis that this enzyme can also help generate viral sequence diversification and the evolution of beneficial viral variants, we have examined the impact of A3G on the acquisition of (−)2′,3′-dideoxy-3′-thiacytidine (3TC) resistance in vitro. That characteristic resistance mutations are rapidly fixed in the presence of A3G and 3TC suggests that A3G-mediated editing can be an important source of genetic variation on which natural selection acts to shape the structure of HIV-1 populations.

scholarly journals Structural variants of IFNα preferentially promote antiviral functions

Blood ◽  
2011 ◽  
Vol 118 (9) ◽  
pp. 2567-2577 ◽  
Author(s):  
Nancy Vázquez ◽  
Hana Schmeisser ◽  
Michael A. Dolan ◽  
Joseph Bekisz ◽  
Kathryn C. Zoon ◽  
...  
Keyword(s):  
Intracellular Signaling ◽  
Structural Changes ◽  
Negative Effects ◽  
Mrna Editing ◽  
Hiv Replication ◽  
Innate And Adaptive Immunity ◽  
Antiviral Genes ◽  
Reduced Toxicity ◽  
And Function ◽  
Editing Enzyme

AbstractIFNα, a cytokine with multiple functions in innate and adaptive immunity and a potent inhibitor of HIV, exerts antiviral activity, in part, by enhancing apolipoprotein B mRNA-editing enzyme-catalytic polypeptide-like 3 (APOBEC3) family members. Although IFNα therapy is associated with reduced viral burden, this cytokine also mediates immune dysfunction and toxicities. Through detailed mapping of IFNα receptor binding sites, we generated IFNα hybrids and mutants and determined that structural changes in the C-helix alter the ability of IFN to limit retroviral activity. Selective IFNα constructs differentially block HIV replication and their directional magnitude of inhibition correlates with APOBEC3 levels. Importantly, certain mutants exhibited reduced toxicity as reflected by induced indoleamine 2,3-dioxygenase (IDO), suggesting discreet and shared intracellular signaling pathways. Defining IFN structure and function relative to APOBEC and other antiviral genes may enable design of novel IFN-related molecules preserving beneficial antiviral roles while minimizing negative effects.

A Mucin-Specific Protease Enables Molecular and Functional Analysis of Human Cancer-Associated Mucins

2018 ◽  
Author(s):  
Stacy A. Malaker ◽  
Kayvon Pedram ◽  
Michael J. Ferracane ◽  
Elliot C. Woods ◽  
Jessica Kramer ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Molecular Mechanisms ◽  
Cultured Cells ◽  
High Resolution Mass Spectrometry ◽  
Human Cancer ◽  
Glycosylation Sites ◽  
Bacterial Protease ◽  
Specific Protease ◽  
To Come ◽  
And Function

<div> <div> <div> <p>Mucins are a class of highly O-glycosylated proteins that are ubiquitously expressed on cellular surfaces and are important for human health, especially in the context of carcinomas. However, the molecular mechanisms by which aberrant mucin structures lead to tumor progression and immune evasion have been slow to come to light, in part because methods for selective mucin degradation are lacking. Here we employ high resolution mass spectrometry, polymer synthesis, and computational peptide docking to demonstrate that a bacterial protease, called StcE, cleaves mucin domains by recognizing a discrete peptide-, glycan-, and secondary structure- based motif. We exploited StcE’s unique properties to map glycosylation sites and structures of purified and recombinant human mucins by mass spectrometry. As well, we found that StcE will digest cancer-associated mucins from cultured cells and from ovarian cancer patient-derived ascites fluid. Finally, using StcE we discovered that Siglec-7, a glyco-immune checkpoint receptor, specifically binds sialomucins as biological ligands, whereas the related Siglec-9 receptor does not. Mucin-specific proteolysis, as exemplified by StcE, is therefore a powerful tool for the study of glycoprotein structure and function and for deorphanizing mucin-binding receptors. </p> </div> </div> </div>

scholarly journals Mechanosensation and Mechanotransduction by Lymphatic Endothelial Cells Act as Important Regulators of Lymphatic Development and Function

2021 ◽  
Vol 22 (8) ◽  
pp. 3955
Author(s):  
László Bálint ◽  
Zoltán Jakus
Keyword(s):  
Endothelial Cells ◽  
Endothelial Cell ◽  
Cell Fate ◽  
Molecular Mechanisms ◽  
Critical Role ◽  
Mechanical Forces ◽  
Lymphatic Endothelial Cells ◽  
Lymphatic Development ◽  
And Function ◽  
The Impact

Our understanding of the function and development of the lymphatic system is expanding rapidly due to the identification of specific molecular markers and the availability of novel genetic approaches. In connection, it has been demonstrated that mechanical forces contribute to the endothelial cell fate commitment and play a critical role in influencing lymphatic endothelial cell shape and alignment by promoting sprouting, development, maturation of the lymphatic network, and coordinating lymphatic valve morphogenesis and the stabilization of lymphatic valves. However, the mechanosignaling and mechanotransduction pathways involved in these processes are poorly understood. Here, we provide an overview of the impact of mechanical forces on lymphatics and summarize the current understanding of the molecular mechanisms involved in the mechanosensation and mechanotransduction by lymphatic endothelial cells. We also discuss how these mechanosensitive pathways affect endothelial cell fate and regulate lymphatic development and function. A better understanding of these mechanisms may provide a deeper insight into the pathophysiology of various diseases associated with impaired lymphatic function, such as lymphedema and may eventually lead to the discovery of novel therapeutic targets for these conditions.

scholarly journals Mutational analysis of apolipoprotein B mRNA editing enzyme (APOBEC1): structure–function relationships of RNA editing and dimerization

1999 ◽  
Vol 40 (4) ◽  
pp. 623-635 ◽  
Author(s):  
Ba-Bie Teng ◽  
Scott Ochsner ◽  
Qian Zhang ◽  
Kizhake V. Soman ◽  
Paul P. Lau ◽  
...  
Keyword(s):  
Structure Function ◽  
Rna Editing ◽  
Apolipoprotein B ◽  
Mutational Analysis ◽  
Mrna Editing ◽  
Editing Enzyme

scholarly journals Emerging Data on the Diversity of Molecular Mechanisms Involving C/D snoRNAs

2021 ◽  
Vol 7 (2) ◽  
pp. 30
Author(s):  
Laeya Baldini ◽  
Bruno Charpentier ◽  
Stéphane Labialle
Keyword(s):  
Ribosomal Rna ◽  
Molecular Mechanisms ◽  
Molecular Level ◽  
Accurate Description ◽  
Small Nucleolar Rnas ◽  
Age Of Maturity ◽  
Non Coding Rnas ◽  
And Function ◽  
Nucleolar Rnas

Box C/D small nucleolar RNAs (C/D snoRNAs) represent an ancient family of small non-coding RNAs that are classically viewed as housekeeping guides for the 2′-O-methylation of ribosomal RNA in Archaea and Eukaryotes. However, an extensive set of studies now argues that they are involved in mechanisms that go well beyond this function. Here, we present these pieces of evidence in light of the current comprehension of the molecular mechanisms that control C/D snoRNA expression and function. From this inventory emerges that an accurate description of these activities at a molecular level is required to let the snoRNA field enter in a second age of maturity.

scholarly journals The Cross-Talk between Mesenchymal Stem Cells and Immune Cells in Tissue Repair and Regeneration

2021 ◽  
Vol 22 (5) ◽  
pp. 2472
Author(s):  
Carl Randall Harrell ◽  
Valentin Djonov ◽  
Vladislav Volarevic
Keyword(s):  
Stem Cells ◽  
Mesenchymal Stem Cells ◽  
Immune Cells ◽  
Tissue Repair ◽  
Molecular Mechanisms ◽  
Current Knowledge ◽  
Multipotent Stem Cells ◽  
Tissue Repair And Regeneration ◽  
Almost All ◽  
And Function

Mesenchymal stem cells (MSCs) are self-renewable, rapidly proliferating, multipotent stem cells which reside in almost all post-natal tissues. MSCs possess potent immunoregulatory properties and, in juxtacrine and paracrine manner, modulate phenotype and function of all immune cells that participate in tissue repair and regeneration. Additionally, MSCs produce various pro-angiogenic factors and promote neo-vascularization in healing tissues, contributing to their enhanced repair and regeneration. In this review article, we summarized current knowledge about molecular mechanisms that regulate the crosstalk between MSCs and immune cells in tissue repair and regeneration.

scholarly journals Expression and function of Smad7 in autoimmune and inflammatory diseases

2021 ◽  
Author(s):  
Yiping Hu ◽  
Juan He ◽  
Lianhua He ◽  
Bihua Xu ◽  
Qingwen Wang
Keyword(s):  
Posttranscriptional Regulation ◽  
Molecular Mechanisms ◽  
Transforming Growth Factor ◽  
Inflammatory Diseases ◽  
Kidney Diseases ◽  
Critical Role ◽  
Transforming Growth Factor Β ◽  
Negative Regulator ◽  
Signaling Mechanism ◽  
And Function

AbstractTransforming growth factor-β (TGF-β) plays a critical role in the pathological processes of various diseases. However, the signaling mechanism of TGF-β in the pathological response remains largely unclear. In this review, we discuss advances in research of Smad7, a member of the I-Smads family and a negative regulator of TGF-β signaling, and mainly review the expression and its function in diseases. Smad7 inhibits the activation of the NF-κB and TGF-β signaling pathways and plays a pivotal role in the prevention and treatment of various diseases. Specifically, Smad7 can not only attenuate growth inhibition, fibrosis, apoptosis, inflammation, and inflammatory T cell differentiation, but also promotes epithelial cells migration or disease development. In this review, we aim to summarize the various biological functions of Smad7 in autoimmune diseases, inflammatory diseases, cancers, and kidney diseases, focusing on the molecular mechanisms of the transcriptional and posttranscriptional regulation of Smad7.

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