scholarly journals RACK1 associates with RNA-binding proteins Vigilin and SERBP1 to control dengue virus replication

2021 ◽  
Author(s):  
Alexis Brugier ◽  
Mohamed-Lamine Hafirassou ◽  
Marie Pourcelot ◽  
Morgane Baldaccini ◽  
Laurine Couture ◽  
...  
Keyword(s):  
Dengue Virus ◽  
Binding Proteins ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Ribosomal Subunit ◽  
Denv Infection ◽  
Mass Spectrometry Analysis ◽  
Macromolecular Complex ◽  
Loss Of Function ◽  
Spectrometry Analysis

Dengue virus (DENV), a re-emerging virus transmitted by Aedes mosquitoes, causes severe pathogenesis in humans. No effective treatment is available against this virus. We recently identified the scaffold protein RACK1 as a component of the DENV replication complex, a macromolecular complex essential for viral genome amplification. Here, we show that RACK1 is important for DENV infection. RACK1 mediates DENV replication through binding to the 40S ribosomal subunit. Mass spectrometry analysis of RACK1 partners coupled to a loss-of-function screen identified the RNA binding proteins Vigilin and SERBP1 as DENV host dependency factors. Vigilin and SERBP1 interact with DENV viral RNA (vRNA), forming a ternary complex with RACK1 to mediate viral replication. Overall, our results indicate that RACK1 recruits Vigilin and SERBP1, linking the DENV vRNA to the translation machinery for optimal translation and replication.

scholarly journals Revealing the Proteome of Motor Cortex Derived Extracellular Vesicles Isolated from Amyotrophic Lateral Sclerosis Human Postmortem Tissues

Cells ◽  
2020 ◽  
Vol 9 (7) ◽  
pp. 1709
Author(s):  
Natasha Vassileff ◽  
Laura J. Vella ◽  
Harinda Rajapaksha ◽  
Mitch Shambrook ◽  
Amirmohammad Nasiri Kenari ◽  
...  
Keyword(s):  
Amyotrophic Lateral Sclerosis ◽  
Motor Cortex ◽  
Extracellular Vesicles ◽  
Motor Neurons ◽  
Binding Proteins ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Mass Spectrometry Analysis ◽  
Spectrometry Analysis ◽  
Lateral Sclerosis

Amyotrophic Lateral Sclerosis (ALS) is a neurodegenerative disease characterized by the deposition of misfolded proteins in the motor cortex and motor neurons. Although a multitude of ALS-associated mutated proteins have been identified, several have been linked to small extracellular vesicles such as exosomes involved in cell−cell communication. This study aims to determine the proteome of extracellular vesicles isolated from the motor cortex of ALS subjects and to identify novel ALS-associated deregulated proteins. Motor cortex extracellular vesicles (MCEVs) were isolated from human postmortem ALS (n = 10) and neurological control (NC, n = 5) motor cortex brain tissues and the MCEVs protein content subsequently underwent mass spectrometry analysis, allowing for a panel of ALS-associated proteins to be identified. This panel consists of 16 statistically significant differentially packaged proteins identified in the ALS MCEVs. This includes several upregulated RNA-binding proteins which were determined through pathway analysis to be associated with stress granule dynamics. The identification of these RNA-binding proteins in the ALS MCEVs suggests there may be a relationship between ALS-associated stress granules and ALS MCEV packaging, highlighting a potential role for small extracellular vesicles such as exosomes in the pathogenesis of ALS and as potential peripheral biomarkers for ALS.

scholarly journals Identification of novel proteins and mRNAs differentially bound to the Leishmania Poly(A) Binding Proteins reveals a direct association between PABP1, the RNA-binding protein RBP23 and mRNAs encoding ribosomal proteins

2021 ◽  
Vol 15 (10) ◽  
pp. e0009899
Author(s):  
Ludmila A. Assis ◽  
Moezio V. C. Santos Filho ◽  
Joao R. da Cruz Silva ◽  
Maria J. R. Bezerra ◽  
Irassandra R. P. U. C. de Aquino ◽  
...  
Keyword(s):  
Ribosomal Proteins ◽  
Binding Proteins ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Mrna Translation ◽  
Mass Spectrometry Analysis ◽  
Sequencing Analysis ◽  
Direct Role ◽  
Spectrometry Analysis

Poly(A) Binding Proteins (PABPs) are major eukaryotic RNA-binding proteins (RBPs) with multiple roles associated with mRNA stability and translation and characterized mainly from multicellular organisms and yeasts. A variable number of PABP homologues are seen in different organisms however the biological reasons for multiple PABPs are generally not well understood. In the unicellular Leishmania, dependent on post-transcriptional mechanisms for the control of its gene expression, three distinct PABPs are found, with yet undefined functional distinctions. Here, using RNA-immunoprecipitation sequencing analysis we show that the Leishmania PABP1 preferentially associates with mRNAs encoding ribosomal proteins, while PABP2 and PABP3 bind to an overlapping set of mRNAs distinct to those enriched in PABP1. Immunoprecipitation studies combined to mass-spectrometry analysis identified RBPs differentially associated with PABP1 or PABP2, including RBP23 and DRBD2, respectively, that were investigated further. Both RBP23 and DRBD2 bind directly to the three PABPs in vitro, but reciprocal experiments confirmed preferential co-immunoprecipitation of PABP1, as well as the EIF4E4/EIF4G3 based translation initiation complex, with RBP23. Other RBP23 binding partners also imply a direct role in translation. DRBD2, in contrast, co-immunoprecipitated with PABP2, PABP3 and with RBPs unrelated to translation. Over 90% of the RBP23-bound mRNAs code for ribosomal proteins, mainly absent from the transcripts co-precipitated with DRBD2. These experiments suggest a novel and specific route for translation of the ribosomal protein mRNAs, mediated by RBP23, PABP1 and the associated EIF4E4/EIF4G3 complex. They also highlight the unique roles that different PABP homologues may have in eukaryotic cells associated with mRNA translation.

scholarly journals Multiple roles of heterogeneous nuclear ribonucleoprotein K during skeletal muscle cell differentiation

2021 ◽  
Author(s):  
Keisuke Hitachi ◽  
Yuri Kiyofuji ◽  
Masashi Nakatani ◽  
Kunihiro Tsuchida
Keyword(s):  
Binding Proteins ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Protein Complexes ◽  
Myogenic Differentiation ◽  
Cell Physiology ◽  
Transcriptional Level ◽  
Loss Of Function ◽  
Independent Manner ◽  
Multiple Functions

RNA-binding proteins (RBPs) regulate cell physiology via the formation of ribonucleic-protein complexes with coding and non-coding RNAs. RBPs have multiple functions in the same cells; however, the precise mechanism through which their pleiotropic functions are determined remains unknown. In this study, we revealed the multiple inhibitory functions of hnRNPK for myogenic differentiation. We first identified hnRNPK as a lncRNA Myoparr binding protein. Gain- and loss-of-function experiments showed that hnRNPK repressed the expression of myogenin at the transcriptional level via binding to Myoparr. Moreover, hnRNPK repressed the expression of a set of genes coding for aminoacyl-tRNA synthetases in a Myoparr-independent manner. Mechanistically, hnRNPK regulated the eIF2α/Atf4 pathway, one branch of the intrinsic pathways of the endoplasmic reticulum sensors, in differentiating myoblasts. Thus, our findings demonstrate that hnRNPK plays multiple lncRNA-dependent and -independent roles in the inhibition of myogenic differentiation, indicating that the analysis of lncRNA-binding proteins will be useful for elucidating both the physiological functions of lncRNAs and the multiple functions of RBPs.

scholarly journals Identification of Proteins Bound to Dengue Viral RNA In Vivo Reveals New Host Proteins Important for Virus Replication

mBio ◽  
2016 ◽  
Vol 7 (1) ◽  
Author(s):  
Stacia L. Phillips ◽  
Erik J. Soderblom ◽  
Shelton S. Bradrick ◽  
Mariano A. Garcia-Blanco
Keyword(s):  
Mass Spectrometry ◽  
Dengue Virus ◽  
Virus Replication ◽  
Binding Proteins ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Viral Rna ◽  
Host Proteins ◽  
Infected Cells

ABSTRACT Dengue virus is the most prevalent cause of arthropod-borne infection worldwide. Due to the limited coding capacity of the viral genome and the complexity of the viral life cycle, host cell proteins play essential roles throughout the course of viral infection. Host RNA-binding proteins mediate various aspects of virus replication through their physical interactions with viral RNA. Here we describe a technique designed to identify such interactions in the context of infected cells using UV cross-linking followed by antisense-mediated affinity purification and mass spectrometry. Using this approach, we identified interactions, several of them novel, between host proteins and dengue viral RNA in infected Huh7 cells. Most of these interactions were subsequently validated using RNA immunoprecipitation. Using small interfering RNA (siRNA)-mediated gene silencing, we showed that more than half of these host proteins are likely involved in regulating virus replication, demonstrating the utility of this method in identifying biologically relevant interactions that may not be identified using traditional in vitro approaches. IMPORTANCE Dengue virus is the most prevalent cause of arthropod-borne infection worldwide. Viral RNA molecules physically interact with cellular RNA-binding proteins (RBPs) throughout the course of infection; the identification of such interactions will lead to the elucidation of the molecular mechanisms of virus replication. Until now, the identification of host proteins bound to dengue viral RNA has been accomplished using in vitro strategies. Here, we used a method for the specific purification of dengue viral ribonucleoprotein (RNP) complexes from infected cells and subsequently identified the associated proteins by mass spectrometry. We then validated a functional role for the majority of these proteins in mediating efficient virus replication. This approach has broad relevance to virology and RNA biology, as it could theoretically be used to purify any viral RNP complex of interest.

scholarly journals FUS ALS-causative mutations impact FUS autoregulation and the processing of RNA-binding proteins through intron retention

2019 ◽  
Author(s):  
Jack Humphrey ◽  
Nicol Birsa ◽  
Carmelo Milioto ◽  
David Robaldo ◽  
Andrea B Eberle ◽  
...  
Keyword(s):  
Motor Neurons ◽  
Binding Proteins ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Intron Retention ◽  
Loss Of Function ◽  
Sequencing Data ◽  
Induced Changes ◽  
The Impact ◽  
Progressive Weakness

AbstractMutations in the RNA-binding protein FUS cause amyotrophic lateral sclerosis (ALS), a devastating neurodegenerative disease in which the loss of motor neurons induces progressive weakness and death from respiratory failure, typically only 3-5 years after onset. FUS plays a role in numerous aspects of RNA metabolism, including mRNA splicing. However, the impact of ALS-causative mutations on splicing has not been fully characterised, as most disease models have been based on FUS overexpression, which in itself alters its RNA processing functions. To overcome this, we and others have recently created knock-in models, and have generated high depth RNA-sequencing data on FUS mutants in parallel to FUS knockout. We combined three independent datasets with a joint modelling approach, allowing us to compare the mutation-induced changes to genuine loss of function. We find that FUS ALS-mutations induce a widespread loss of function on expression and splicing, with a preferential effect on RNA binding proteins. Mutant FUS induces intron retention changes through RNA binding, and we identify an intron retention event in FUS itself that is associated with its autoregulation. Altered FUS regulation has been linked to disease, and intriguingly, we find FUS autoregulation to be altered not only by FUS mutations, but also in other genetic forms of ALS, including those caused by TDP-43, VCP and SOD1 mutations, supporting the concept that multiple ALS genes interact in a regulatory network.

eIF4E-binding proteins: new factors, new locations, new roles

2014 ◽  
Vol 42 (4) ◽  
pp. 1238-1245 ◽  
Author(s):  
Anastasiia Kamenska ◽  
Clare Simpson ◽  
Nancy Standart
Keyword(s):  
Binding Proteins ◽  
Rna Binding ◽  
Gene Expression Regulation ◽  
Rna Binding Proteins ◽  
Ribosomal Subunit ◽  
Translation Initiation Factor ◽  
Initiation Factor ◽  
Eukaryotic Initiation Factor 4E ◽  
New Locations ◽  
Specific Mrnas

The cap-binding translation initiation factor eIF4E (eukaryotic initiation factor 4E) is central to protein synthesis in eukaryotes. As an integral component of eIF4F, a complex also containing the large bridging factor eIF4G and eIF4A RNA helicase, eIF4E enables the recruitment of the small ribosomal subunit to the 5′ end of mRNAs. The interaction between eIF4E and eIF4G via a YXXXXLϕ motif is regulated by small eIF4E-binding proteins, 4E-BPs, which use the same sequence to competitively bind eIF4E thereby inhibiting cap-dependent translation. Additional eIF4E-binding proteins have been identified in the last 10–15 years, characterized by the YXXXXLϕ motif, and by interactions (many of which remain to be detailed) with RNA-binding proteins, or other factors in complexes that recognize the specific mRNAs. In the present article, we focus on the metazoan 4E-T (4E-transporter)/Cup family of eIF4E-binding proteins, and also discuss very recent examples in yeast, fruitflies and humans, some of which predictably inhibit translation, while others may result in mRNA decay or even enhance translation; altogether considerably expanding our understanding of the roles of eIF4E-binding proteins in gene expression regulation.

scholarly journals An RNA tagging approach for system-wide RNA-binding proteome profiling and dynamics investigation upon transcription inhibition

2021 ◽  
Author(s):  
Zheng Zhang ◽  
Tong Liu ◽  
Hangyan Dong ◽  
Jian Li ◽  
Haofan Sun ◽  
...  
Keyword(s):  
Protein Interactions ◽  
Large Scale ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Decay Rates ◽  
Mass Spectrometry Analysis ◽  
Transcription Inhibition ◽  
Distribution Profile ◽  
Proteome Profiling ◽  
Spectrometry Analysis

Abstract RNA-protein interactions play key roles in epigenetic, transcriptional and posttranscriptional regulation. To reveal the regulatory mechanisms of these interactions, global investigation of RNA-binding proteins (RBPs) and monitor their changes under various physiological conditions are needed. Herein, we developed a psoralen probe (PP)-based method for RNA tagging and ribonucleic-protein complex (RNP) enrichment. Isolation of both coding and noncoding RNAs and mapping of 2986 RBPs including 782 unknown candidate RBPs from HeLa cells was achieved by PP enrichment, RNA-sequencing and mass spectrometry analysis. The dynamics study of RNPs by PP enrichment after the inhibition of RNA synthesis provides the first large-scale distribution profile of RBPs bound to RNAs with different decay rates. Furthermore, the remarkably greater decreases in the abundance of the RBPs obtained by PP-enrichment than by global proteome profiling suggest that PP enrichment after transcription inhibition offers a valuable way for large-scale evaluation of the candidate RBPs.

scholarly journals RNA-binding proteins with mixed charge domains self-assemble and aggregate in Alzheimer’s Disease

2018 ◽  
Author(s):  
Isaac Bishof ◽  
Eric B. Dammer ◽  
Duc M. Duong ◽  
Marla Gearing ◽  
James J. Lah ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Binding Proteins ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Significant Proportion ◽  
Mass Spectrometry Analysis ◽  
Rna Granules ◽  
Intrinsically Disordered ◽  
Small Nuclear Ribonucleoprotein

ABSTRACTU1 small nuclear ribonucleoprotein 70 kDa (U1-70K) and other RNA binding proteins (RBPs) are mislocalized to cytoplasmic neurofibrillary Tau aggregates in Alzheimer’s disease (AD), yet understanding of the mechanisms that cause their aggregation is limited. Many RBPs that aggregate in neurodegenerative diseases self-assemble into RNA granules through intrinsically disordered low complexity (LC) domains. We report here that a LC domain within U1-70K of mixed charge, containing highly repetitive complementary repeats of basic (R/K) and acidic (D/E) residues, shares many of the same properties of the Q/N-rich LC domains found in the RBPs TDP-43 and FUS. These properties include the ability to self-assemble into oligomers, and to form nuclear granules. To analyze the functional roles of the U1-70K LC domains, we performed co-immunoprecipitation and quantitative mass spectrometry analysis of recombinant U1-70K and deletions lacking the C-terminal LC domain(s). A network-driven approach resolved functional classes of U1-70K interacting proteins that showed dependency on the U1-70K LC domain(s) for their interaction. This included structurally similar RBPs, such as LUC7L3 and RBM25, which require their respective mixed charge domains for reciprocal interactions with U1-70K and for participation in nuclear RNA granules. Strikingly, a significant proportion of RBPs with mixed charge domains have elevated insolubility in AD brain proteome compared to controls. Furthermore, we show that the mixed charge LC domain of U1-70K can interact with Tau from AD brain. These findings highlight mechanisms for mixed charge domains in stabilizing RBP interactions and in potentially mediating co-aggregation with pathological Tau isoforms in AD.

Niclosamide’s potential direct targets in ovarian cancer

2021 ◽  
Author(s):  
Nikola Sekulovski ◽  
James A MacLean ◽  
Sambasiva R Bheemireddy ◽  
Zhifeng Yu ◽  
Hiroshi Okuda ◽  
...  
Keyword(s):  
Ovarian Cancer ◽  
Cell Viability ◽  
Cancer Cells ◽  
High Throughput Screening ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Affinity Purification ◽  
Mass Spectrometry Analysis ◽  
Ovarian Cancer Cells ◽  
Spectrometry Analysis

Abstract Recent evidence indicates that niclosamide is an anti-cancer compound that is able to inhibit several signaling pathways. While niclosamide has previously been identified by high-throughput screening platforms as a potential effective compound against several cancer types, no direct binding interactions with distinct biological molecule(s) has been established. The present study identifies key signal transduction mechanisms altered by niclosamide in ovarian cancer. Using affinity purification with a biotin-modified niclosamide derivative and mass spectrometry analysis, several RNA binding proteins were identified. We chose two, FXR1 and IGF2BP2, for further analysis. A significant correlation exists in which high-expression of FXR1 or IGF2BP2 is associated with reduced survival of ovarian cancer patients. Knockdown of FXR1 or IGF2BP2 in ovarian cancer cells resulted in significantly reduced cell viability, adhesion, and migration. Furthermore, FXR1 or IGF2BP2 deficient ovarian cancer cells exhibited reduced response to most doses of niclosamide showing greater cell viability than those with intact RBPs. These results suggest that FXR1 and IGF2BP2 are direct targets of niclosamide and could have critical activities that drive multiple oncogenic pathways in ovarian cancer.

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