scholarly journals Identification of Nrl1 Domains Responsible for Interactions with RNA-Processing Factors and Regulation of Nrl1 Function by Phosphorylation

2021 ◽  
Vol 22 (13) ◽  
pp. 7011
Author(s):  
Barbora Mikolaskova ◽  
Matus Jurcik ◽  
Ingrid Cipakova ◽  
Tomas Selicky ◽  
Jan Jurcik ◽  
...  
Keyword(s):  
Gene Expression ◽  
Rna Processing ◽  
Affinity Purification ◽  
Regulation Of Gene Expression ◽  
Terminal Region ◽  
Mass Spectrometry Analysis ◽  
Post Translational Modification ◽  
Vitro Assay ◽  
Spectrometry Analysis

Pre-mRNA splicing is a key process in the regulation of gene expression. In the fission yeast Schizosaccharomyces pombe, Nrl1 regulates splicing and expression of several genes and non-coding RNAs, and also suppresses the accumulation of R-loops. Here, we report analysis of interactions between Nrl1 and selected RNA-processing proteins and regulation of Nrl1 function by phosphorylation. Bacterial two-hybrid system (BACTH) assays revealed that the N-terminal region of Nrl1 is important for the interaction with ATP-dependent RNA helicase Mtl1 while the C-terminal region of Nrl1 is important for interactions with spliceosome components Ctr1, Ntr2, and Syf3. Consistent with this result, tandem affinity purification showed that Mtl1, but not Ctr1, Ntr2, or Syf3, co-purifies with the N-terminal region of Nrl1. Interestingly, mass-spectrometry analysis revealed that in addition to previously identified phosphorylation sites, Nrl1 is also phosphorylated on serines 86 and 112, and that Nrl1-TAP co-purifies with Cka1, the catalytic subunit of casein kinase 2. In vitro assay showed that Cka1 can phosphorylate bacterially expressed Nrl1 fragments. An analysis of non-phosphorylatable nrl1 mutants revealed defects in gene expression and splicing consistent with the notion that phosphorylation is an important regulator of Nrl1 function. Taken together, our results provide insights into two mechanisms that are involved in the regulation of the spliceosome-associated factor Nrl1, namely domain-specific interactions between Nrl1 and RNA-processing proteins and post-translational modification of Nrl1 by phosphorylation.

scholarly journals Identification of Novel Surface Proteins of Anaplasma phagocytophilum by Affinity Purification and Proteomics

2007 ◽  
Vol 189 (21) ◽  
pp. 7819-7828 ◽  
Author(s):  
Yan Ge ◽  
Yasuko Rikihisa
Keyword(s):  
Anaplasma Phagocytophilum ◽  
Affinity Purification ◽  
The United States ◽  
Capillary Liquid Chromatography ◽  
Etiologic Agent ◽  
Surface Proteins ◽  
Mass Spectrometry Analysis ◽  
Spectrometry Analysis ◽  
Major Surface

ABSTRACT Anaplasma phagocytophilum is the etiologic agent of human granulocytic anaplasmosis (HGA), one of the major tick-borne zoonoses in the United States. The surface of A. phagocytophilum plays a crucial role in subverting the hostile host cell environment. However, except for the P44/Msp2 outer membrane protein family, the surface components of A. phagocytophilum are largely unknown. To identify the major surface proteins of A. phagocytophilum, a membrane-impermeable, cleavable biotin reagent, sulfosuccinimidyl-2-[biotinamido]ethyl-1,3-dithiopropionate (Sulfo-NHS-SS-Biotin), was used to label intact bacteria. The biotinylated bacterial surface proteins were isolated by streptavidin agarose affinity purification and then separated by electrophoresis, followed by capillary liquid chromatography-nanospray tandem mass spectrometry analysis. Among the major proteins captured by affinity purification were five A. phagocytophilum proteins, Omp85, hypothetical proteins APH_0404 (designated Asp62) and APH_0405 (designated Asp55), P44 family proteins, and Omp-1A. The surface exposure of Asp62 and Asp55 was verified by immunofluorescence microscopy. Recombinant Asp62 and Asp55 proteins were recognized by an HGA patient serum. Anti-Asp62 and anti-Asp55 peptide sera partially neutralized A. phagocytophilum infection of HL-60 cells in vitro. We found that the Asp62 and Asp55 genes were cotranscribed and conserved among members of the family Anaplasmataceae. With the exception of P44-18, all of the proteins were newly revealed major surface-exposed proteins whose study should facilitate understanding the interaction between A. phagocytophilum and the host. These proteins may serve as targets for development of chemotherapy, diagnostics, and vaccines.

Modeling of drug-drug interactions between omeprazole and erythromycin with cytochrome P450 3A4 in vitro assay

2020 ◽  
Vol 66 (3) ◽  
pp. 241-249
Author(s):  
P.I. Koroleva ◽  
A.V. Kuzikov ◽  
R.A. Masamrekh ◽  
D.A. Filimonov ◽  
A.V. Dmitriev ◽  
...  
Keyword(s):  
Cytochrome P450 ◽  
Drug Interactions ◽  
Eradication Therapy ◽  
Mass Spectrometry Analysis ◽  
Cytochrome P450 3A4 ◽  
Vitro Assay ◽  
Spectrometry Analysis ◽  
Omeprazole Sulfone ◽  
Demethylase Activity

In the present study the electrochemical system based on recombinant cytochrome P450 3A4 (CYP3A4) was used for the investigation of potential drug-drug interaction between medicinal preparations employed for Helicobacter pylori eradication therapy. Drug interactions were demonstrated in association of omeprazole as a proton pump inhibitor (PPI) and macrolide antibiotic erythromycin during cytochrome P450 3A4-mediated metabolism. It was shown that in the presence of omeprazole the rate of N-demethylase activity of CYP3A4 to erythromycin measured by means of product (formaldehyde) formation decreased. Mass-spectrometry analysis of omeprazole sulfone as a CYP3A4-mediated metabolite demonstrated the absence of erythromycin influence on CYP3A4-dependent omeprazole metabolism. This phenomenon may be explained by lower spectral dissociation constant of CYP3A4-omeprazole complex (Kd = 18±2 μM) than that of CYP3A4-erythromycin complex (Kd = 52 μM). Using the electrochemical model of electrochemically-driven drug metabolism it is possible to register CYP3A4-mediated catalytic conversion of certain drugs. In vitro experiments of potential CYP3A4-mediated drug-drug interactions are in accordance with in silico modeling with program PASS and PoSMNA descriptors in the case of omeprazole/erythromycin combinations.

scholarly journals Host Cell Calpains Can Cleave Structural Proteins from the Enterovirus Polyprotein

Viruses ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 1106 ◽  
Author(s):  
Mira Laajala ◽  
Minna M. Hankaniemi ◽  
Juha A. E. Määttä ◽  
Vesa P. Hytönen ◽  
Olli H. Laitinen ◽  
...  
Keyword(s):  
Mass Spectrometry Analysis ◽  
Structural Proteins ◽  
Calpain Inhibitor ◽  
Nonstructural Proteins ◽  
Vitro Assay ◽  
Spectrometry Analysis ◽  
Viral Proteases ◽  
Infected Cells ◽  
Calpain 2

Enteroviruses are small RNA viruses that cause diseases with various symptoms ranging from mild to severe. Enterovirus proteins are translated as a single polyprotein, which is cleaved by viral proteases to release capsid and nonstructural proteins. Here, we show that also cellular calpains have a potential role in the processing of the enteroviral polyprotein. Using purified calpains 1 and 2 in an in vitro assay, we show that addition of calpains leads to an increase in the release of VP1 and VP3 capsid proteins from P1 of enterovirus B species, detected by western blotting. This was prevented with a calpain inhibitor and was dependent on optimal calcium concentration, especially for calpain 2. In addition, calpain cleavage at the VP3-VP1 interface was supported by a competition assay using a peptide containing the VP3-VP1 cleavage site. Moreover, a mass spectrometry analysis showed that calpains can cleave this same peptide at the VP3-VP1 interface, the cutting site being two amino acids aside from 3C’s cutting site. Furthermore, we show that calpains cannot cleave between P1 and 2A. In conclusion, we show that cellular proteases, calpains, can cleave structural proteins from enterovirus polyprotein in vitro. Whether they assist polyprotein processing in infected cells remains to be shown.

scholarly journals Locus-Conserved Circular RNA cZNF292 Controls Endothelial Cell Flow Responses

2021 ◽  
Author(s):  
Andreas W Heumüller ◽  
Alisha Nicole Jones ◽  
André Mourão ◽  
Marius Klangwart ◽  
Chenyue Shi ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Laminar Flow ◽  
Affinity Purification ◽  
Mass Spectrometry Analysis ◽  
Circular Rnas ◽  
Cell Orientation ◽  
Spectrometry Analysis ◽  
Functional Conservation

Background : Circular RNAs (circRNAs) are generated by back-splicing of mostly mRNAs and are gaining increasing attention as a novel class of regulatory RNAs that control various cellular functions. However, their physiological roles and functional conservation in vivo are rarely addressed, given the inherent challenges of their genetic inactivation. Here we aimed to identify locus conserved circRNAs in mice and humans, which can be genetically deleted due to retained intronic elements not contained in the mRNA host gene to eventually address functional conservation. Methods: Mechanistically, we identified the protein syndesmos (SDOS) to specifically interact with cZNF292 in endothelial cells by RNA affinity purification and subsequent mass spectrometry analysis. Silencing of SDOS or its protein binding partner Syndecan-4, or mutation of the SDOS-cZNF292 binding site, prevented laminar flow-induced cytoskeletal reorganisation thereby recapitulating cZfp292 phenotypes. Results: Combining published endothelial RNA sequencing datasets with circRNAs of the circATLAS databank, we identified locus-conserved circRNA retaining intronic elements between mice and humans. CRISPR/Cas9 mediated genetic depletion of the top expressed circRNA cZfp292 resulted in an altered endothelial morphology and aberrant flow alignment in the aorta in vivo. Consistently, depletion of cZNF292 in endothelial cells in vitro abolished laminar flow-induced alterations in cell orientation, paxillin localisation and focal adhesion organisation. Conclusion: Together, our data reveal a hitherto unknown role of cZNF292/cZfp292 in endothelial flow responses, which influences endothelial shape.

scholarly journals Development, validation, and application of the ribosome separation and reconstitution system for protein translation in vitro

2021 ◽  
Author(s):  
Brandon M Trainor ◽  
Dimitri G Pestov ◽  
Natalia Shcherbik
Keyword(s):  
Gene Expression ◽  
Regulation Of Gene Expression ◽  
Mrna Translation ◽  
Protein Translation ◽  
Transcription Control ◽  
Vitro Assay ◽  
Control Of Gene Expression ◽  
Translational Machinery ◽  
The Impact

The conventional view regarding regulation of gene expression is based on transcription control. However, a growing number of recent studies has revealed the important additional impact of translational regulation. Eukaryotic translational machinery appears to be capable of reprogramming mRNA translation to generate proteins required to maintain a healthy cellular proteostasis under particular physiological conditions or to adapt to stress. Although the mechanisms of such remarkable regulation are beginning to emerge, recent studies have identified the ribosome as one of the major constituents of translation-dependent control of gene expression that is especially important during stress. Built of RNA and proteins, ribosomes are susceptible to environmental and intracellular stresses. How stress-modified ribosomes regulate translation and whether they play a role in stress-induced gene expression remain largely elusive. This knowledge gap is likely due to the lack of an appropriate experimental system. Canonical approaches based on exposing cells or cell-free extracts to stressors provide inconclusive results due to off-target effects of modifying agents. Here we describe a robust and simple in vitro assay that allows separation of yeast ribosomes from other translational machinery constituents, followed by reconstitution of the translation reaction. This ribosome separation and reconstitution assay (RSR) is highly advantageous, as it allows modification of ribosomes without compromising other key translational components, followed by supplementing the ribosomes back into translation reactions containing undamaged, translationally-competent yeast lysate. Besides addressing the impact of ribosome-derived stress on translation, RSR can also be used to characterize mutated ribosomes and ribosomes devoid of associated factors.

scholarly journals Molecular Architecture of the Essential Yeast Histone Acetyltransferase Complex NuA4 Redefines Its Multimodularity

2018 ◽  
Vol 38 (9) ◽  
Author(s):  
Dheva Setiaputra ◽  
Salar Ahmad ◽  
Udit Dalwadi ◽  
Anne-Lise Steunou ◽  
Shan Lu ◽  
...  
Keyword(s):  
Cell Fate ◽  
Histone Acetyltransferase ◽  
Structural Information ◽  
Regulation Of Gene Expression ◽  
Mass Spectrometry Analysis ◽  
Molecular Architecture ◽  
Catalytic Core ◽  
Spectrometry Analysis ◽  
Subunit Organization

ABSTRACT Conserved from yeast to humans, the NuA4 histone acetyltransferase is a large multisubunit complex essential for cell viability through the regulation of gene expression, genome maintenance, metabolism, and cell fate during development and stress. How the different NuA4 subunits work in concert with one another to perform these diverse functions remains unclear, and addressing this central question requires a comprehensive understanding of NuA4's molecular architecture and subunit organization. We have determined the structure of fully assembled native yeast NuA4 by single-particle electron microscopy. Our data revealed that NuA4 adopts a trilobal overall architecture, with each of the three lobes constituted by one or two functional modules. By performing cross-linking coupled to mass spectrometry analysis and in vitro protein interaction studies, we further mapped novel intermolecular interfaces within NuA4. Finally, we combined these new data with other known structural information of NuA4 subunits and subassemblies to construct a multiscale model to illustrate how the different NuA4 subunits and modules are spatially arranged. This model shows that the multiple chromatin reader domains are clustered together around the catalytic core, suggesting that NuA4's multimodular architecture enables it to engage in multivalent interactions with its nucleosome substrate.

scholarly journals Identification of Phosphorylated Amino Acids in Human TNRC6A C-Terminal Region and Their Effects on the Interaction with the CCR4-NOT Complex

Genes ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 271
Author(s):  
Fusako Munakata ◽  
Masataka Suzawa ◽  
Kumiko Ui-Tei
Keyword(s):  
Rna Silencing ◽  
Terminal Region ◽  
Scaffold Proteins ◽  
Mass Spectrometry Analysis ◽  
Post Translational Modification ◽  
Related Factors ◽  
Spectrometry Analysis ◽  
Binding Domains ◽  
Family Protein ◽  
Related Proteins

Human GW182 family proteins have Argonaute (AGO)-binding domains in their N-terminal regions and silencing domains, which interact with RNA silencing-related proteins, in their C-terminal regions. Thus, they function as scaffold proteins between the AGO protein and RNA silencing-related proteins, such as carbon catabolite repressor4-negative on TATA (CCR4-NOT) or poly(A)-binding protein (PABP). Our mass spectrometry analysis and the phosphorylation data registered in PhosphoSitePlus, a post-translational modification database, suggested that the C-terminal region of a human GW182 family protein, TNRC6A, has at least four possible phosphorylation sites, which are located near the region interacting with the CCR4-NOT complex. Among them, two serine residues at amino acid positions 1332 and 1346 (S1332 and S1346) were certainly phosphorylated in human HeLa cells, but other two serine residues (S1616 and S1691) were not phosphorylated. Furthermore, it was revealed that the phosphorylation patterns of TNRC6A affect the interaction with the CCR4-NOT complex. When S1332 and S1346 were dephosphorylated, the interactions of TNRC6A with the CCR4-NOT complex were enhanced, and when S1616 and S1691 were phosphorylated, such interaction was suppressed. Thus, phosphorylation of TNRC6A was considered to regulate the interaction with RNA silencing-related factors that may affect RNA silencing activity.

Review of Progress in Predicting Protein Methylation Sites

2019 ◽  
Vol 23 (15) ◽  
pp. 1663-1670 ◽  
Author(s):  
Chunyan Ao ◽  
Shunshan Jin ◽  
Yuan Lin ◽  
Quan Zou
Keyword(s):  
Gene Expression ◽  
Signal Transduction ◽  
Transcriptional Activity ◽  
Regulation Of Gene Expression ◽  
Protein Methylation ◽  
Biological Processes ◽  
Post Translational Modification ◽  
Regulatory Enzymes ◽  
Lysine Residues ◽  
Arginine Residues

Protein methylation is an important and reversible post-translational modification that regulates many biological processes in cells. It occurs mainly on lysine and arginine residues and involves many important biological processes, including transcriptional activity, signal transduction, and the regulation of gene expression. Protein methylation and its regulatory enzymes are related to a variety of human diseases, so improved identification of methylation sites is useful for designing drugs for a variety of related diseases. In this review, we systematically summarize and analyze the tools used for the prediction of protein methylation sites on arginine and lysine residues over the last decade.

scholarly journals Phytochemicals of Minthostachys diffusa Epling and Their Health-Promoting Bioactivities

Foods ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 144
Author(s):  
Immacolata Faraone ◽  
Daniela Russo ◽  
Lucia Chiummiento ◽  
Eloy Fernandez ◽  
Alka Choudhary ◽  
...  
Keyword(s):  
Ethyl Acetate ◽  
Radical Scavenging ◽  
Ethyl Acetate Fraction ◽  
Mass Spectrometry Analysis ◽  
Antioxidant Power ◽  
Spectrometry Analysis ◽  
In Silico Docking ◽  
Aerial Parts ◽  
Health Promoting

The genus Minthostachys belonging to the Lamiaceae family, and is an important South American mint genus used commonly in folk medicine as an aroma in cooking. The phytochemical-rich samples of the aerial parts of Minthostachys diffusa Epling. were tested for pharmacological and health-promoting bioactivities using in vitro chemical and enzymatic assays. A range of radical scavenging activities of the samples against biological radicals such as nitric oxide and superoxide anion and against synthetic 2,2-diphenyl-1-picrylhydrazyl and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radicals, the ferric reducing antioxidant power and the lipid peroxidation inhibition were determined and ranked using the ‘relative antioxidant capacity index’ (RACI). The ethyl acetate fraction showed the highest RACI of +1.12. Analysis of the various fractions’ inhibitory ability against enzymes involved in diabetes (α-amylase and α-glucosidase), and against enzymes associated with Parkinson’s or Alzheimer’s diseases (acetylcholinesterase and butyrylcholinesterase) also suggested that the ethyl acetate fraction was the most active. Liquid chromatography–tandem mass spectrometry analysis of the ethyl acetate fraction showed more than 30 polyphenolic compounds, including triterpenes. The inhibitory cholinesterase effects of the triterpenes identified from M. diffusa were further analysed by in silico docking of these compounds into 3D-structures of acetylcholinesterase and butyrylcholinesterase. This is the first study on pharmacological activities and phytochemical profiling of the aerial parts of M. diffusa, showing that this plant, normally used as food in South America, is also rich in health-promoting phytochemicals.

scholarly journals N-Terminomics Strategies for Protease Substrates Profiling

Molecules ◽  
2021 ◽  
Vol 26 (15) ◽  
pp. 4699
Author(s):  
Mubashir Mintoo ◽  
Amritangshu Chakravarty ◽  
Ronak Tilvawala
Keyword(s):  
Mass Spectrometry ◽  
Protease Activity ◽  
Viral Infections ◽  
Mass Spectrometry Analysis ◽  
Post Translational Modification ◽  
Spectrometry Analysis ◽  
Physiological Conditions ◽  
Inflammatory Conditions ◽  
Biological Mixtures

Proteases play a central role in various biochemical pathways catalyzing and regulating key biological events. Proteases catalyze an irreversible post-translational modification called proteolysis by hydrolyzing peptide bonds in proteins. Given the destructive potential of proteolysis, protease activity is tightly regulated. Dysregulation of protease activity has been reported in numerous disease conditions, including cancers, neurodegenerative diseases, inflammatory conditions, cardiovascular diseases, and viral infections. The proteolytic profile of a cell, tissue, or organ is governed by protease activation, activity, and substrate specificity. Thus, identifying protease substrates and proteolytic events under physiological conditions can provide crucial information about how the change in protease regulation can alter the cellular proteolytic landscape. In recent years, mass spectrometry-based techniques called N-terminomics have become instrumental in identifying protease substrates from complex biological mixtures. N-terminomics employs the labeling and enrichment of native and neo-N-termini peptides, generated upon proteolysis followed by mass spectrometry analysis allowing protease substrate profiling directly from biological samples. In this review, we provide a brief overview of N-terminomics techniques, focusing on their strengths, weaknesses, limitations, and providing specific examples where they were successfully employed to identify protease substrates in vivo and under physiological conditions. In addition, we explore the current trends in the protease field and the potential for future developments.

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