scholarly journals Receptor-specific interactome as a hub for rapid cue-induced selective translation in axons

2019 ◽  
Author(s):  
Max Koppers ◽  
Roberta Cagnetta ◽  
Toshiaki Shigeoka ◽  
Lucia C.S. Wunderlich ◽  
Sixian Zhao ◽  
...  
Keyword(s):  
Rna Binding ◽  
Rna Binding Proteins ◽  
Axon Growth ◽  
Mrna Translation ◽  
Local Translation ◽  
Simultaneous Exposure ◽  
Surface Receptors ◽  
Guidance Cue ◽  
Selective Translation ◽  
Specific Mrnas

AbstractDuring neuronal wiring, extrinsic cues trigger the local translation of specific mRNAs in axons via cell surface receptors. The coupling of ribosomes to receptors has been proposed as a mechanism linking signals to local translation but it is not known how broadly this mechanism operates, nor whether it can selectively regulate mRNA translation. We report that receptor-ribosome coupling is employed by multiple guidance cue receptors and this interaction is mRNA-dependent. We find that different receptors bind to distinct sets of mRNAs and RNA-binding proteins. Cue stimulation induces rapid dissociation of ribosomes from receptors and the selective translation of receptor-specific mRNAs in retinal axon growth cones. Further, we show that receptor-ribosome dissociation and cue-induced selective translation are inhibited by simultaneous exposure to translation-repressive cues, suggesting a novel mode of signal integration. Our findings reveal receptor-specific interactomes and provide a general model for the rapid, localized and selective control of cue-induced translation.

scholarly journals Receptor-specific interactome as a hub for rapid cue-induced selective translation in axons

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Max Koppers ◽  
Roberta Cagnetta ◽  
Toshiaki Shigeoka ◽  
Lucia CS Wunderlich ◽  
Pedro Vallejo-Ramirez ◽  
...  
Keyword(s):  
Rna Binding ◽  
Rna Binding Proteins ◽  
Mrna Translation ◽  
Retinal Ganglion ◽  
Local Translation ◽  
Surface Receptors ◽  
Guidance Cue ◽  
Extrinsic Cues ◽  
Selective Translation ◽  
Specific Mrnas

Extrinsic cues trigger the local translation of specific mRNAs in growing axons via cell surface receptors. The coupling of ribosomes to receptors has been proposed as a mechanism linking signals to local translation but it is not known how broadly this mechanism operates, nor whether it can selectively regulate mRNA translation. We report that receptor-ribosome coupling is employed by multiple guidance cue receptors and this interaction is mRNA-dependent. We find that different receptors associate with distinct sets of mRNAs and RNA-binding proteins. Cue stimulation of growing Xenopus retinal ganglion cell axons induces rapid dissociation of ribosomes from receptors and the selective translation of receptor-specific mRNAs. Further, we show that receptor-ribosome dissociation and cue-induced selective translation are inhibited by co-exposure to translation-repressive cues, suggesting a novel mode of signal integration. Our findings reveal receptor-specific interactomes and suggest a generalizable model for cue-selective control of the local proteome.

scholarly journals G3BP1-linked mRNA partitioning supports selective protein synthesis in response to oxidative stress

2020 ◽  
Vol 48 (12) ◽  
pp. 6855-6873 ◽  
Author(s):  
Syam Prakash Somasekharan ◽  
Fan Zhang ◽  
Neetu Saxena ◽  
Jia Ni Huang ◽  
I-Chih Kuo ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Mrna Translation ◽  
Stress Adaptation ◽  
Rna Granules ◽  
Before And After ◽  
Selective Translation ◽  
Energy Consuming ◽  
Limit Energy

Abstract Cells limit energy-consuming mRNA translation during stress to maintain metabolic homeostasis. Sequestration of mRNAs by RNA binding proteins (RBPs) into RNA granules reduces their translation, but it remains unclear whether RBPs also function in partitioning of specific transcripts to polysomes (PSs) to guide selective translation and stress adaptation in cancer. To study transcript partitioning under cell stress, we catalogued mRNAs enriched in prostate carcinoma PC-3 cell PSs, as defined by polysome fractionation and RNA sequencing (RNAseq), and compared them to mRNAs complexed with the known SG-nucleator protein, G3BP1, as defined by spatially-restricted enzymatic tagging and RNAseq. By comparing these compartments before and after short-term arsenite-induced oxidative stress, we identified three major categories of transcripts, namely those that were G3BP1-associated and PS-depleted, G3BP1-dissociated and PS-enriched, and G3BP1-associated but also PS-enriched. Oxidative stress profoundly altered the partitioning of transcripts between these compartments. Under arsenite stress, G3BP1-associated and PS-depleted transcripts correlated with reduced expression of encoded mitochondrial proteins, PS-enriched transcripts that disassociated from G3BP1 encoded cell cycle and cytoprotective proteins whose expression increased, while transcripts that were both G3BP1-associated and PS-enriched encoded proteins involved in diverse stress response pathways. Therefore, G3BP1 guides transcript partitioning to reprogram mRNA translation and support stress adaptation.

Signalling to translation: how signal transduction pathways control the protein synthetic machinery

2007 ◽  
Vol 403 (2) ◽  
pp. 217-234 ◽  
Author(s):  
Christopher G. Proud
Keyword(s):  
Protein Synthesis ◽  
Protein Kinases ◽  
Mammalian Cells ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Mrna Translation ◽  
Signalling Pathways ◽  
Cancer Tissue ◽  
Energy Status ◽  
Specific Mrnas

Recent advances in our understanding of both the regulation of components of the translational machinery and the upstream signalling pathways that modulate them have provided important new insights into the mechanisms by which hormones, growth factors, nutrients and cellular energy status control protein synthesis in mammalian cells. The importance of proper control of mRNA translation is strikingly illustrated by the fact that defects in this process or its control are implicated in a number of disease states, such as cancer, tissue hypertrophy and neurodegeneration. Signalling pathways such as those involving mTOR (mammalian target of rapamycin) and mitogen-activated protein kinases modulate the phosphorylation of translation factors, the activities of the protein kinases that act upon them and the association of RNA-binding proteins with specific mRNAs. These effects contribute both to the overall control of protein synthesis (which is linked to cell growth) and to the modulation of the translation or stability of specific mRNAs. However, important questions remain about both the contributions of individual regulatory events to the control of general protein synthesis and the mechanisms by which the translation of specific mRNAs is controlled.

RNA-Binding Proteins and Translation in Neurodegenerative Disease

2020 ◽  
Author(s):  
Kent E. Duncan
Keyword(s):  
Neurodegenerative Diseases ◽  
Binding Proteins ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Fragile X ◽  
Potential Contribution ◽  
Fused In Sarcoma ◽  
Specific Mrnas ◽  
Ataxia Syndrome ◽  
Research Frontiers

Both RNA-binding proteins (RBPs) and translation are increasingly implicated in several neurodegenerative diseases, but their specific roles in promoting disease are not yet fully defined. This chapter critically evaluates the evidence that altered translation of specific mRNAs mediated by RNA-binding proteins plays an important role in driving specific neurodegenerative diseases. First, diseases are discussed where a causal role for RNA-binding proteins in disease appears solid, but whether this involves altered translation is less clear. The main foci here are TAR DNA-binding protein (TDP-43) and fused in sarcoma (FUS) in amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Subsequently, diseases are presented where altered translation is believed to contribute, but involvement of RNA-binding proteins is less clear. These include Huntington’s and other repeat expansion disorders such as fragile X tremor/ataxia syndrome (FXTAS), where repeat-induced non-AUG-initiated (RAN) translation is a focus. The potential contribution of both canonical and non-canonical RBPs to altered translation in Parkinson’s disease is discussed. The chapter closes by proposing key research frontiers for the field to explore and outlining methodological advances that could help to address them.

scholarly journals RNA-binding proteins La and HuR cooperatively modulate translation repression of PDCD4 mRNA

2020 ◽  
pp. jbc.RA120.014894
Author(s):  
Ravi Kumar ◽  
Dipak Kumar Poria ◽  
Partho Sarothi Ray
Keyword(s):  
Inflammatory Response ◽  
Chronic Inflammation ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Critical Role ◽  
Regulation Of Gene Expression ◽  
Mrna Translation ◽  
Suppressor Gene ◽  
Cooperative Action ◽  
Translation Repression

Post-transcriptional regulation of gene expression plays a critical role in controlling the inflammatory response. An uncontrolled inflammatory response results in chronic inflammation, often leading to tumorigenesis. Programmed cell death 4 (PDCD4) is a pro-inflammatory tumor-suppressor gene which helps to prevent the transition from chronic inflammation to cancer. PDCD4 mRNA translation is regulated by an interplay between the oncogenic microRNA miR-21 and the RNA-binding protein (RBP) HuR in response to LPS stimulation, but the role of other regulatory factors remain unknown. Here we report that the RBP Lupus antigen (La) interacts with the 3’UTR of PDCD4 mRNA and prevents miR-21-mediated translation repression. While LPS causes nuclear-cytoplasmic translocation of HuR, it enhances cellular La expression. Remarkably, La and HuR were found to bind cooperatively to the PDCD4 mRNA and mitigate miR-21-mediated translation repression. The cooperative action of La and HuR reduced cell proliferation and enhanced apoptosis, reversing the pro-oncogenic function of miR-21. Together, these observations demonstrate a cooperative interplay between two RBPs, triggered differentially by the same stimulus, which exerts a synergistic effect on PDCD4 expression and thereby helps maintain a balance between inflammation and tumorigenesis.

scholarly journals TRIBE editing reveals specific mRNA targets of eIF4E-BP in Drosophila and in mammals

2020 ◽  
Author(s):  
Hua Jin ◽  
Daxiang Na ◽  
Reazur Rahman ◽  
Weijin Xu ◽  
Allegra Fieldsend ◽  
...  
Keyword(s):  
Rna Binding ◽  
Rna Binding Proteins ◽  
Growth Control ◽  
Ribosome Profiling ◽  
Translational Efficiency ◽  
Mtor Inhibition ◽  
Mrna Targets ◽  
Specific Mrnas ◽  
Specific Mrna

Abstract4E-BP (eIF4E-BP) represses translation initiation by binding to the 5’cap-binding protein eIF4E and inhibiting its activity. Although 4E-BP has been shown to be important in growth control, stress response, cancer, neuronal activity and mammalian circadian rhythms, it is not understood how it preferentially represses a subset of mRNAs. We successfully used hyperTRIBE (Targets of RNA-binding proteins identified by editing) to identify in vivo 4E-BP mRNA targets in both Drosophila and mammals under conditions known to activate 4E-BP. The protein associates with specific mRNAs, and ribosome profiling data show that mTOR inhibition changes the translational efficiency of 4E-BP TRIBE targets compared to non-targets. In both systems, these targets have specific motifs and are enriched in translation-related pathways, which correlate well with the known activity of 4E-BP and suggest that it modulates the binding specificity of eIF4E and contributes to mTOR translational specificity.

scholarly journals Specific Anchoring and Local Translation of Poxviral ATI mRNA at Cytoplasmic Inclusion Bodies

2019 ◽  
Vol 94 (4) ◽  
Author(s):  
George C. Katsafanas ◽  
Bernard Moss
Keyword(s):  
Inclusion Bodies ◽  
Actin Polymerization ◽  
Rna Binding ◽  
Protein Localization ◽  
Cytoplasmic Inclusion ◽  
Mrna Translation ◽  
Translation Initiation Factor ◽  
Initiation Factor ◽  
Local Translation ◽  
Virion Assembly

ABSTRACT On-site translation of mRNAs provides an efficient means of subcellular protein localization. In eukaryotic cells, the transport of cellular mRNAs to membraneless sites usually occurs prior to translation and involves specific sequences known as zipcodes that interact with RNA binding and motor proteins. Poxviruses replicate in specialized cytoplasmic factory regions where DNA synthesis, transcription, translation, and virion assembly occur. Some poxviruses embed infectious virus particles outside of factories in membraneless protein bodies with liquid gel-like properties known as A-type inclusions (ATIs) that are comprised of numerous copies of the viral 150-kDa ATI protein. Here, we demonstrate by fluorescent in situ hybridization that these inclusions are decorated with ATI mRNA. On-site translation is supported by the localization of a translation initiation factor eIF4E and by ribosome-bound nascent chain ribopuromycylation. Nascent peptide-mediated anchoring of ribosome-mRNA translation complexes to the inclusions is suggested by release of the mRNA by puromycin, a peptide chain terminator. Following puromycin washout, relocalization of ATI mRNA at inclusions depends on RNA and protein synthesis but requires neither microtubules nor actin polymerization. Further studies show that the ATI mRNAs remain near the sites of transcription in the factory regions when stop codons are introduced near the N terminus of the ATI or large truncations are made at the N or C termini. Instead of using a zipcode, we propose that ATI mRNA localization is mediated by ribosome-bound nascent ATI polypeptides that interact with ATI protein in inclusions and thereby anchor the complex for multiple rounds of mRNA translation. IMPORTANCE Poxvirus genome replication, transcription, translation, and virion assembly occur at sites within the cytoplasm known as factories. Some poxviruses sequester infectious virions outside of the factories in inclusion bodies comprised of numerous copies of the 150-kDa ATI protein, which can provide stability and protection in the environment. We provide evidence that ATI mRNA is anchored by nascent peptides and translated at the inclusion sites rather than in virus factories. Association of ATI mRNA with inclusion bodies allows multiple rounds of local translation and prevents premature ATI protein aggregation and trapping of virions within the factory.

scholarly journals A potential role for a novel ZC3H5 complex in regulating mRNA translation in Trypanosoma brucei

2020 ◽  
Vol 295 (42) ◽  
pp. 14291-14304
Author(s):  
Kathrin Bajak ◽  
Kevin Leiss ◽  
Christine Clayton ◽  
Esteban Erben
Keyword(s):  
Gene Expression ◽  
Trypanosoma Brucei ◽  
Binding Proteins ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Binding Protein ◽  
Affinity Purification ◽  
Critical Role ◽  
Rna Binding Protein ◽  
Mrna Translation

In Trypanosoma brucei and related kinetoplastids, gene expression regulation occurs mostly posttranscriptionally. Consequently, RNA-binding proteins play a critical role in the regulation of mRNA and protein abundance. Yet, the roles of many RNA-binding proteins are not understood. Our previous research identified the RNA-binding protein ZC3H5 as possibly involved in gene repression, but its role in controlling gene expression was unknown. We here show that ZC3H5 is an essential cytoplasmic RNA-binding protein. RNAi targeting ZC3H5 causes accumulation of precytokinetic cells followed by rapid cell death. Affinity purification and pairwise yeast two-hybrid analysis suggest that ZC3H5 forms a complex with three other proteins, encoded by genes Tb927.11.4900, Tb927.8.1500, and Tb927.7.3040. RNA immunoprecipitation revealed that ZC3H5 is preferentially associated with poorly translated, low-stability mRNAs, the 5′-untranslated regions and coding regions of which are enriched in the motif (U/A)UAG(U/A). As previously found in high-throughput analyses, artificial tethering of ZC3H5 to a reporter mRNA or other complex components repressed reporter expression. However, depletion of ZC3H5 in vivo caused only very minor decreases in a few targets, marked increases in the abundances of very stable mRNAs, an increase in monosomes at the expense of large polysomes, and appearance of “halfmer” disomes containing two 80S subunits and one 40S subunit. We speculate that the ZC3H5 complex might be implicated in quality control during the translation of suboptimal open reading frames.

Targeting of transcripts encoding membrane proteins in polarized epithelia: RNA–protein binding studies of the SGLT1 3′-UTR

2008 ◽  
Vol 36 (3) ◽  
pp. 525-527 ◽  
Author(s):  
Christopher M. Pedder ◽  
Dianne Ford ◽  
John E. Hesketh
Keyword(s):  
Binding Proteins ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Protein Localization ◽  
Complex Structure ◽  
Mrna Translation ◽  
Drosophila Embryo ◽  
Binding Studies ◽  
Polarized Epithelia ◽  
Apical Localization

mRNA stability, mRNA translation and spatial localization of mRNA species within a cell can be governed by signals in the 3′-UTR (3′-untranslated region). Local translation of proteins is essential for the development of many eukaryotic cell types, such as the Drosophila embryo, where the spatial and temporal localization of bicoid and gurken mRNAs, among others, is required to establish morphogen gradients. More recent studies have suggested that mRNA localization also occurs with transcripts coding for membrane-based or secreted proteins, and that localization at organelles such as the endoplasmic reticulum directs translation more efficiently to specific subdomains, so as to aid correct protein localization. In human epithelial cells, the mRNA coding for SGLT1 (sodium–glucose co-transporter 1), an apical membrane protein, has been shown to be localized apically in polarized cells. However, the nature of the signals and RNA-binding proteins involved are unknown. Ongoing work is aimed at identifying the localization signals in the SGLT1 3′-UTR and the corresponding binding proteins. Using a protein extract from polarized Caco-2 cells, both EMSAs (electrophoretic mobility-shift assays) and UV cross-linking assays have shown that a specific protein complex is formed with the first 300 bases of the 3′-UTR sequence. MFold predictions suggest that this region folds into a complex structure and ongoing studies using a series of strategic deletions are being carried out to identify the precise nature of the motif involved, particularly the role of the sequence or RNA secondary structure, as well as to identify the main proteins present within the complex. Such information will provide details of the post-transcriptional events that lead to apical localization of the SGLT1 transcript and may reveal mechanisms of more fundamental importance in the apical localization of proteins in polarized epithelia.

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