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Nature Communications Jul 2022Insulin is a potent inducer of mRNA transcription and translation, contributing to metabolic regulation. Insulin has also been suggested to regulate mRNA stability...
Insulin is a potent inducer of mRNA transcription and translation, contributing to metabolic regulation. Insulin has also been suggested to regulate mRNA stability through the processing body (P-body) molecular machinery. However, whether and how insulin regulates mRNA stability via P-bodies is not clear. Here we show that the E3-ligase TRIM24 is a critical factor linking insulin signalling to P-bodies. Upon insulin stimulation, protein kinase B (PKB, also known as Akt) phosphorylates TRIM24 and stimulates its shuttling from the nucleus into the cytoplasm. TRIM24 interacts with several critical components of P-bodies in the cytoplasm, promoting their polyubiquitylation, which consequently stabilises PparĪ³ mRNA. Inactivation of TRIM24 E3-ligase activity or prevention of its phosphorylation via knockin mutations in mice promotes hepatic PparĪ³ degradation via P-bodies. Consequently, both knockin mutations alleviate hepatosteatosis in mice fed on a high-fat diet. Our results demonstrate the critical role of TRIM24 in linking insulin signalling to P-bodies and have therapeutic implications for the treatment of hepatosteatosis.
Topics: Animals; Insulin; Mice; Nuclear Proteins; PPAR gamma; Processing Bodies; RNA, Messenger; Transcription Factors; Ubiquitin-Protein Ligases
PubMed: 35803934
DOI: 10.1038/s41467-022-31735-0 -
Nucleic Acids Research Jul 2022Processing bodies (P-bodies) are ribonucleoprotein granules that contain mRNAs, RNA-binding proteins and effectors of mRNA turnover. While P-bodies have been reported to...
Processing bodies (P-bodies) are ribonucleoprotein granules that contain mRNAs, RNA-binding proteins and effectors of mRNA turnover. While P-bodies have been reported to contain translationally repressed mRNAs, a causative role for P-bodies in regulating mRNA decay has yet to be established. Enhancer of decapping protein 4 (EDC4) is a core P-body component that interacts with multiple mRNA decay factors, including the mRNA decapping (DCP2) and decay (XRN1) enzymes. EDC4 also associates with the RNA endonuclease MARF1, an interaction that antagonizes the decay of MARF1-targeted mRNAs. How EDC4 interacts with MARF1 and how it represses MARF1 activity is unclear. In this study, we show that human MARF1 and XRN1 interact with EDC4 using analogous conserved short linear motifs in a mutually exclusive manner. While the EDC4-MARF1 interaction is required for EDC4 to inhibit MARF1 activity, our data indicate that the interaction with EDC4 alone is not sufficient. Importantly, we show that P-body architecture plays a critical role in antagonizing MARF1-mediated mRNA decay. Taken together, our study suggests that P-bodies can directly regulate mRNA turnover by sequestering an mRNA decay enzyme and preventing it from interfacing with and degrading targeted mRNAs.
Topics: Cell Cycle Proteins; Endoribonucleases; Exoribonucleases; Humans; Microtubule-Associated Proteins; Proteins; RNA Stability; RNA, Messenger; RNA-Binding Proteins
PubMed: 35801873
DOI: 10.1093/nar/gkac557 -
Molecular Cell May 2019Cellular RNAs often colocalize with cytoplasmic, membrane-less ribonucleoprotein (RNP) granules enriched for RNA-processing enzymes, termed processing bodies (PBs). Here...
Cellular RNAs often colocalize with cytoplasmic, membrane-less ribonucleoprotein (RNP) granules enriched for RNA-processing enzymes, termed processing bodies (PBs). Here we track the dynamic localization of individual miRNAs, mRNAs, and long non-coding RNAs (lncRNAs) to PBs using intracellular single-molecule fluorescence microscopy. We find that unused miRNAs stably bind to PBs, whereas functional miRNAs, repressed mRNAs, and lncRNAs both transiently and stably localize within either the core or periphery of PBs, albeit to different extents. Consequently, translation potential and 3' versus 5' placement of miRNA target sites significantly affect the PB localization dynamics of mRNAs. Using computational modeling and supporting experimental approaches, we show that partitioning in the PB phase attenuates mRNA silencing, suggesting that physiological mRNA turnover occurs predominantly outside of PBs. Instead, our data support a PB role in sequestering unused miRNAs for surveillance and provide a framework for investigating the dynamic assembly of RNP granules by phase separation at single-molecule resolution.
Topics: Cytoplasmic Granules; Gene Silencing; HeLa Cells; Humans; MicroRNAs; RNA Processing, Post-Transcriptional; RNA, Long Noncoding; RNA, Messenger; RNA, Untranslated; Ribonucleoproteins; Single Molecule Imaging
PubMed: 30952514
DOI: 10.1016/j.molcel.2019.03.001 -
RNA (New York, N.Y.) May 2006Processing bodies (P-bodies) are cellular structures that have critical roles in mRNA degradation and post-transcriptional gene silencing. Some patients with autoimmune... (Comparative Study)
Comparative Study
Processing bodies (P-bodies) are cellular structures that have critical roles in mRNA degradation and post-transcriptional gene silencing. Some patients with autoimmune disease have high titer antibodies directed against P-bodies, and certain sera have been used as markers for the GW182 component of these structures. This study shows that available reference sera are unreliable markers for GW182 because the sera contain antibodies directed against Ge-1, a second P-body autoantigen.
Topics: Argonaute Proteins; Autoantibodies; Autoantigens; Autoimmune Diseases; Carcinoma, Hepatocellular; Cell Line, Tumor; Eukaryotic Initiation Factor-2; Fluorescent Antibody Technique, Indirect; Fluorescent Dyes; Green Fluorescent Proteins; Humans; Immunoblotting; Indoles; Liver Neoplasms; Nuclear Proteins; Peptide Initiation Factors; Proteins; RNA, Messenger; RNA-Induced Silencing Complex
PubMed: 16641511
DOI: 10.1261/rna.17406 -
Cold Spring Harbor Perspectives in... Sep 2012The control of translation and mRNA degradation is important in the regulation of eukaryotic gene expression. In general, translation and steps in the major pathway of... (Review)
Review
The control of translation and mRNA degradation is important in the regulation of eukaryotic gene expression. In general, translation and steps in the major pathway of mRNA decay are in competition with each other. mRNAs that are not engaged in translation can aggregate into cytoplasmic mRNP granules referred to as processing bodies (P-bodies) and stress granules, which are related to mRNP particles that control translation in early development and neurons. Analyses of P-bodies and stress granules suggest a dynamic process, referred to as the mRNA Cycle, wherein mRNPs can move between polysomes, P-bodies and stress granules although the functional roles of mRNP assembly into higher order structures remain poorly understood. In this article, we review what is known about the coupling of translation and mRNA degradation, the properties of P-bodies and stress granules, and how assembly of mRNPs into larger structures might influence cellular function.
Topics: Cytoplasmic Granules; Gene Expression Regulation; Models, Genetic; Peptide Chain Initiation, Translational; Protein Biosynthesis; RNA Stability; RNA, Messenger; Ribonucleoproteins
PubMed: 22763747
DOI: 10.1101/cshperspect.a012286 -
Biochemical Society Transactions Aug 2008NMD (nonsense-mediated mRNA decay) is a mechanism that degrades transcripts containing PTCs (premature translation termination codons). NMD is a translation-associated... (Review)
Review
NMD (nonsense-mediated mRNA decay) is a mechanism that degrades transcripts containing PTCs (premature translation termination codons). NMD is a translation-associated process that is expected to take place throughout the cytoplasm. However, recent studies have indicated that the core NMD factors UPF1 (up-frameshift-1), UPF2 and UPF3 can associate with P-bodies (processing bodies), which are large cytoplasmic granules replete with proteins involved in general mRNA decay and related processes. It has been proposed that UPF1 directs PTC-containing mRNAs to P-bodies and triggers decay. Here, we discuss the link between P-bodies and NMD in view of recent studies that suggest that P-bodies are not required for NMD in Drosophila.
Topics: Animals; Codon, Nonsense; Cytoplasmic Structures; RNA Stability; RNA, Messenger; RNA-Binding Proteins
PubMed: 18631143
DOI: 10.1042/BST0360698 -
Virology Jun 2014Translationally silenced mRNAs are recruited to two major classes of RNA granules in the cytoplasm, processing bodies (PBs) and stress granules (SGs). We show that PBs...
Translationally silenced mRNAs are recruited to two major classes of RNA granules in the cytoplasm, processing bodies (PBs) and stress granules (SGs). We show that PBs accumulated after human cytomegalovirus (HCMV) infection. PB assembly after HCMV infection was also detected in the presence of the protein synthesis inhibitor, cycloheximide, but required active RNA synthesis. UV-inactivated HCMV virions were sufficient to induce PB accumulation in HFF cells treated with cycloheximide. Viral IE1 RNA did not colocalize with PBs, and we could not detect an effect of PB accumulation on viral growth. These results may indicate that HCMV inhibits the colocalization of IE1 mRNA with PBs, preventing IE1 mRNA decay and translational inhibition.
Topics: Antibodies, Viral; Cells, Cultured; Cytomegalovirus; DNA, Viral; Fibroblasts; Humans; Virus Replication
PubMed: 24928047
DOI: 10.1016/j.virol.2014.04.022 -
PLoS Biology Jul 2023Microglia-mediated neuroinflammation is involved in various neurological diseases, including ischemic stroke, but the endogenous mechanisms preventing unstrained...
Microglia-mediated neuroinflammation is involved in various neurological diseases, including ischemic stroke, but the endogenous mechanisms preventing unstrained inflammation is still unclear. The anti-inflammatory role of transcription factor nuclear receptor subfamily 4 group A member 1 (NR4A1) in macrophages and microglia has previously been identified. However, the endogenous mechanisms that how NR4A1 restricts unstrained inflammation remain elusive. Here, we observed that NR4A1 is up-regulated in the cytoplasm of activated microglia and localizes to processing bodies (P-bodies). In addition, we found that cytoplasmic NR4A1 functions as an RNA-binding protein (RBP) that directly binds and destabilizes Tnf mRNA in an N6-methyladenosine (m6A)-dependent manner. Remarkably, conditional microglial deletion of Nr4a1 elevates Tnf expression and worsens outcomes in a mouse model of ischemic stroke, in which case NR4A1 expression is significantly induced in the cytoplasm of microglia. Thus, our study illustrates a novel mechanism that NR4A1 posttranscriptionally regulates Tnf expression in microglia and determines stroke outcomes.
Topics: Animals; Mice; Transcription Factors; Microglia; Stroke; Ischemic Stroke; Inflammation; RNA, Messenger
PubMed: 37486903
DOI: 10.1371/journal.pbio.3002199 -
Journal of Virology Jan 2011Metazoan cells form cytoplasmic mRNA granules such as stress granules (SG) and processing bodies (P bodies) that are proposed to be sites of aggregated, translationally...
Metazoan cells form cytoplasmic mRNA granules such as stress granules (SG) and processing bodies (P bodies) that are proposed to be sites of aggregated, translationally silenced mRNAs and mRNA degradation. Poliovirus (PV) is a plus-strand RNA virus containing a genome that is a functional mRNA; thus, we investigated if PV antagonizes the processes that lead to formation of these structures. We have previously shown that PV infection inhibits the ability of cells to form stress granules by cleaving RasGAP-SH3-binding protein (G3BP). Here, we show that P bodies are also disrupted during PV infection in cells by 4 h postinfection. The disruption of P bodies is more rapid and more complete than disruption of stress granules. The kinetics of P body disruption correlated with production of viral proteinases and required substantial viral gene product expression. The organizing mechanism that forms P body foci in cells is unknown; however, potential scaffolding, aggregating, or other regulatory proteins found in P bodies were investigated for degradation. Two factors involved in 5'-end mRNA decapping and degradation, Xrn1 and Dcp1a, and the 3' deadenylase complex component Pan3 underwent accelerated degradation during infection, and Dcp1a may be a direct substrate of PV 3C proteinase. Several other key factors proposed to be essential for P body formation, GW182, Edc3, and Edc4, were unaffected by poliovirus infection. Since deadenylation has been reported to be required for P body formation, viral inhibition of deadenylation, through Pan3 degradation, is a potential mechanism of P body disruption.
Topics: Carrier Proteins; Cell Line; Cytoplasmic Granules; Endoribonucleases; Gene Expression Regulation; HeLa Cells; Humans; Poliovirus; RNA Stability; RNA, Messenger; Trans-Activators; Viral Nonstructural Proteins; Viral Proteins
PubMed: 20962086
DOI: 10.1128/JVI.01657-10 -
Frontiers in Plant Science 2014mRNA accumulation is tightly regulated by diverse molecular pathways. The identification and characterization of enzymes and regulatory proteins involved in controlling... (Review)
Review
mRNA accumulation is tightly regulated by diverse molecular pathways. The identification and characterization of enzymes and regulatory proteins involved in controlling the fate of mRNA offers the possibility to broaden our understanding of posttranscriptional gene regulation. Processing bodies (P bodies, PB) are cytoplasmic protein complexes involved in degradation and translational arrest of mRNA. Composition and dynamics of these subcellular structures have been studied in animal systems, yeasts and in the model plant Arabidopsis. Their assembly implies the aggregation of specific factors related to decapping, deadenylation, and exoribonucleases that operate synchronously to regulate certain mRNA targets during development and adaptation to stress. Although the general function of PB along with the flow of genetic information is understood, several questions still remain open. This review summarizes data on the composition, potential molecular roles, and biological significance of PB and potentially related proteins in Arabidopsis.
PubMed: 24860588
DOI: 10.3389/fpls.2014.00201