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1.
Cell ; 179(5): 1222-1238.e17, 2019 11 14.
Artículo en Inglés | MEDLINE | ID: mdl-31730859

RESUMEN

Mitochondrial dysfunction is associated with a spectrum of human conditions, ranging from rare, inborn errors of metabolism to the aging process. To identify pathways that modify mitochondrial dysfunction, we performed genome-wide CRISPR screens in the presence of small-molecule mitochondrial inhibitors. We report a compendium of chemical-genetic interactions involving 191 distinct genetic modifiers, including 38 that are synthetic sick/lethal and 63 that are suppressors. Genes involved in glycolysis (PFKP), pentose phosphate pathway (G6PD), and defense against lipid peroxidation (GPX4) scored high as synthetic sick/lethal. A surprisingly large fraction of suppressors are pathway intrinsic and encode mitochondrial proteins. A striking example of such "intra-organelle" buffering is the alleviation of a chemical defect in complex V by simultaneous inhibition of complex I, which benefits cells by rebalancing redox cofactors, increasing reductive carboxylation, and promoting glycolysis. Perhaps paradoxically, certain forms of mitochondrial dysfunction may best be buffered with "second site" inhibitors to the organelle.


Asunto(s)
Genes Modificadores , Mitocondrias/genética , Mitocondrias/patología , Autoantígenos/metabolismo , Muerte Celular/efectos de los fármacos , Citosol/efectos de los fármacos , Citosol/metabolismo , Complejo I de Transporte de Electrón/metabolismo , Epistasis Genética/efectos de los fármacos , Ferroptosis/efectos de los fármacos , Ferroptosis/genética , Genoma , Glutatión Peroxidasa/metabolismo , Glucólisis/efectos de los fármacos , Glucólisis/genética , Humanos , Células K562 , Mitocondrias/efectos de los fármacos , Oligomicinas/toxicidad , Oxidación-Reducción , Fosforilación Oxidativa/efectos de los fármacos , Vía de Pentosa Fosfato/efectos de los fármacos , Vía de Pentosa Fosfato/genética , Especies Reactivas de Oxígeno/metabolismo , Ribonucleoproteínas/metabolismo , Antígeno SS-B
2.
Mol Cell ; 81(13): 2838-2850.e6, 2021 07 01.
Artículo en Inglés | MEDLINE | ID: mdl-33989516

RESUMEN

SARS-CoV-2 is an RNA virus whose success as a pathogen relies on its abilities to repurpose host RNA-binding proteins (RBPs) and to evade antiviral RBPs. To uncover the SARS-CoV-2 RNA interactome, we here develop a robust ribonucleoprotein (RNP) capture protocol and identify 109 host factors that directly bind to SARS-CoV-2 RNAs. Applying RNP capture on another coronavirus, HCoV-OC43, revealed evolutionarily conserved interactions between coronaviral RNAs and host proteins. Transcriptome analyses and knockdown experiments delineated 17 antiviral RBPs, including ZC3HAV1, TRIM25, PARP12, and SHFL, and 8 proviral RBPs, such as EIF3D and CSDE1, which are responsible for co-opting multiple steps of the mRNA life cycle. This also led to the identification of LARP1, a downstream target of the mTOR signaling pathway, as an antiviral host factor that interacts with the SARS-CoV-2 RNAs. Overall, this study provides a comprehensive list of RBPs regulating coronaviral replication and opens new avenues for therapeutic interventions.


Asunto(s)
Autoantígenos/genética , COVID-19/genética , ARN Viral/genética , Ribonucleoproteínas/genética , SARS-CoV-2/genética , COVID-19/virología , Coronavirus Humano OC43/genética , Coronavirus Humano OC43/patogenicidad , Células HEK293 , Interacciones Huésped-Patógeno/genética , Humanos , Unión Proteica/genética , Mapas de Interacción de Proteínas/genética , Proteínas de Unión al ARN/genética , SARS-CoV-2/patogenicidad , Serina-Treonina Quinasas TOR/genética , Factores de Transcripción/genética , Transcriptoma/genética , Proteínas de Motivos Tripartitos/genética , Ubiquitina-Proteína Ligasas/genética , Replicación Viral/genética , Antígeno SS-B
3.
Mol Cell ; 73(6): 1127-1137.e5, 2019 03 21.
Artículo en Inglés | MEDLINE | ID: mdl-30772175

RESUMEN

We have previously proposed that selective inheritance, the limited transmission of damaging mtDNA mutations from mother to offspring, is based on replication competition in Drosophila melanogaster. This model, which stems from our observation that wild-type mitochondria propagate much more vigorously in the fly ovary than mitochondria carrying fitness-impairing mutations, implies that germ cells recognize the fitness of individual mitochondria and selectively boost the propagation of healthy ones. Here, we demonstrate that the protein kinase PINK1 preferentially accumulates on mitochondria enriched for a deleterious mtDNA mutation. PINK1 phosphorylates Larp to inhibit protein synthesis on the mitochondrial outer membrane. Impaired local translation on defective mitochondria in turn limits the replication of their mtDNA and hence the transmission of deleterious mutations to the offspring. Our work confirms that selective inheritance occurs at the organelle level during Drosophila oogenesis and provides molecular entry points to test this model in other systems.


Asunto(s)
Replicación del ADN , ADN Mitocondrial/genética , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/enzimología , Mitocondrias/enzimología , Membranas Mitocondriales/enzimología , Proteínas Mitocondriales/biosíntesis , Mutación , Oocitos/enzimología , Proteínas Serina-Treonina Quinasas/metabolismo , Animales , Animales Modificados Genéticamente , ADN Mitocondrial/biosíntesis , Proteínas de Drosophila/genética , Drosophila melanogaster/genética , Femenino , Patrón de Herencia , Mitocondrias/genética , Proteínas Mitocondriales/genética , Oogénesis , Biogénesis de Organelos , Fosforilación , Proteínas Serina-Treonina Quinasas/genética , Estabilidad Proteica , Factores de Transcripción/genética , Factores de Transcripción/metabolismo
4.
RNA Biol ; 21(1): 7-16, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-39016322

RESUMEN

La-related proteins (LARPs) are a family of RNA-binding proteins that share a conserved La motif (LaM) domain. LARP1 plays a role in regulating ribosomal protein synthesis and stabilizing mRNAs and has a unique structure without an RNA binding RRM domain adjoining the LaM domain. In this study, we investigated the physical basis for LARP1 specificity for poly(A) sequences and observed an unexpected bias for sequences with single guanines. Multiple guanine substitutions did not increase the affinity, demonstrating preferential recognition of singly guanylated sequences. We also observed that the cyclic di-nucleotides in the cCAS/STING pathway, cyclic-di-GMP and 3',3'-cGAMP, bound with sub-micromolar affinity. Isothermal titration measurements were complemented by high-resolution crystal structures of the LARP1 LaM with six different RNA ligands, including two stereoisomers of a phosphorothioate linkage. The selectivity for singly substituted poly(A) sequences suggests LARP1 may play a role in the stabilizing effect of poly(A) tail guanylation. [Figure: see text].


Asunto(s)
Poli A , Unión Proteica , Ribonucleoproteínas , Antígeno SS-B , Ribonucleoproteínas/metabolismo , Ribonucleoproteínas/química , Ribonucleoproteínas/genética , Poli A/metabolismo , Poli A/química , Humanos , Modelos Moleculares , Sitios de Unión , Autoantígenos/metabolismo , Autoantígenos/química , Autoantígenos/genética , Cristalografía por Rayos X , Dominios Proteicos , GMP Cíclico/metabolismo , GMP Cíclico/análogos & derivados , GMP Cíclico/química , ARN Mensajero/metabolismo , ARN Mensajero/química , ARN Mensajero/genética
5.
J Biol Chem ; 298(9): 102277, 2022 09.
Artículo en Inglés | MEDLINE | ID: mdl-35863436

RESUMEN

La-related protein 1 (LARP1) has been identified as a key translational inhibitor of terminal oligopyrimidine (TOP) mRNAs downstream of the nutrient sensing protein kinase complex, mTORC1. LARP1 exerts this inhibitory effect on TOP mRNA translation by binding to the mRNA cap and the adjacent 5'TOP motif, resulting in the displacement of the cap-binding protein eIF4E from TOP mRNAs. However, the involvement of additional signaling pathway in regulating LARP1-mediated inhibition of TOP mRNA translation is largely unexplored. In the present study, we identify a second nutrient sensing kinase GCN2 that converges on LARP1 to control TOP mRNA translation. Using chromatin-immunoprecipitation followed by massive parallel sequencing (ChIP-seq) analysis of activating transcription factor 4 (ATF4), an effector of GCN2 in nutrient stress conditions, in WT and GCN2 KO mouse embryonic fibroblasts, we determined that LARP1 is a GCN2-dependent transcriptional target of ATF4. Moreover, we identified GCN1, a GCN2 activator, participates in a complex with LARP1 on stalled ribosomes, suggesting a role for GCN1 in LARP1-mediated translation inhibition in response to ribosome stalling. Therefore, our data suggest that the GCN2 pathway controls LARP1 activity via two mechanisms: ATF4-dependent transcriptional induction of LARP1 mRNA and GCN1-mediated recruitment of LARP1 to stalled ribosomes.


Asunto(s)
Aminoácidos , Biosíntesis de Proteínas , Proteínas Serina-Treonina Quinasas , Secuencia de Oligopirimidina en la Región 5' Terminal del ARN , ARN Mensajero , Proteínas de Unión al ARN , Factor de Transcripción Activador 4/genética , Factor de Transcripción Activador 4/metabolismo , Aminoácidos/metabolismo , Animales , Técnicas de Cultivo de Célula , Inmunoprecipitación de Cromatina , Factor 4E Eucariótico de Iniciación/metabolismo , Fibroblastos , Diana Mecanicista del Complejo 1 de la Rapamicina/metabolismo , Ratones , Ratones Noqueados , Proteínas Serina-Treonina Quinasas/genética , Proteínas Serina-Treonina Quinasas/metabolismo , ARN Mensajero/genética , ARN Mensajero/metabolismo , Proteínas de Unión al ARN/genética , Proteínas de Unión al ARN/metabolismo
6.
Cell Mol Life Sci ; 79(3): 147, 2022 Feb 23.
Artículo en Inglés | MEDLINE | ID: mdl-35195778

RESUMEN

In addition to genomic alterations, aberrant changes in post-transcriptional regulation can modify gene function and drive cancer development. RNA-binding proteins (RBPs) are a large class of post-transcriptional regulators that have been increasingly implicated in carcinogenesis. By integrating multi-omics data, we identify LARP1 as one of the most upregulated RBPs in colorectal cancer (CRC) and demonstrate its oncogenic properties. We perform LARP1:RNA interactome profiling and unveil a previously unexplored role for LARP1 in targeting the 3'UTR of oncogenes in CRC. Notably, we identify the proto-oncogenic transcription factor MYC as a key LARP1-regulated target. Our data show that LARP1 positively modulates MYC expression by associating with its 3'UTR. In addition, antisense oligonucleotide-mediated blocking of the interaction between LARP1 and the MYC 3'UTR reduces MYC expression and in vitro CRC growth. Furthermore, a systematic analysis of LARP1:protein interactions reveals IGF2BP3 and YBX1 as LARP1-interacting proteins that also regulate MYC expression and CRC development. Finally, we demonstrate that MYC reciprocally modulates LARP1 expression by targeting its enhancer. In summary, our data reveal a critical, previously uncharacterized role of LARP1 in promoting CRC tumorigenesis, validate its direct regulation of the proto-oncogene MYC and delineate a model of the positive feedback loop between MYC and LARP1 that promotes CRC growth and development.


Asunto(s)
Autoantígenos/metabolismo , Carcinogénesis/metabolismo , Neoplasias Colorrectales/metabolismo , Retroalimentación Fisiológica , Proteínas Proto-Oncogénicas c-myc/metabolismo , Ribonucleoproteínas/metabolismo , Regiones no Traducidas 3' , Animales , Autoantígenos/genética , Carcinogénesis/genética , Proliferación Celular/genética , Neoplasias Colorrectales/genética , Neoplasias Colorrectales/patología , Regulación Neoplásica de la Expresión Génica , Células HCT116 , Humanos , Ratones , Oncogenes , Ribonucleoproteínas/genética , Transcriptoma/genética , Transfección , Carga Tumoral/genética , Ensayos Antitumor por Modelo de Xenoinjerto , Antígeno SS-B
7.
Proc Natl Acad Sci U S A ; 117(10): 5319-5328, 2020 03 10.
Artículo en Inglés | MEDLINE | ID: mdl-32094190

RESUMEN

Terminal oligopyrimidine (TOP) motifs are sequences at the 5' ends of mRNAs that link their translation to the mTOR Complex 1 (mTORC1) nutrient-sensing signaling pathway. They are commonly regarded as discrete elements that reside on ∼100 mRNAs that mostly encode translation factors. However, the full spectrum of TOP sequences and their prevalence throughout the transcriptome remain unclear, primarily because of uncertainty over the mechanism that detects them. Here, we globally analyzed translation targets of La-related protein 1 (LARP1), an RNA-binding protein and mTORC1 effector that has been shown to repress TOP mRNA translation in a few specific cases. We establish that LARP1 is the primary translation regulator of mRNAs with classical TOP motifs genome-wide, and also that these motifs are extreme instances of a broader continuum of regulatory sequences. We identify the features of TOP sequences that determine their potency and quantify these as a metric that accurately predicts mTORC1/LARP1 regulation called a TOPscore. Analysis of TOPscores across the transcriptomes of 16 mammalian tissues defines a constitutive "core" set of TOP mRNAs, but also identifies tissue-specific TOP mRNAs produced via alternative transcription initiation sites. These results establish the central role of LARP1 in TOP mRNA regulation on a transcriptome scale and show how it connects mTORC1 to a tunable and dynamic program of gene expression that is tailored to specific biological contexts.


Asunto(s)
Autoantígenos/metabolismo , Motivos de Nucleótidos , Proteína de Unión al Tracto de Polipirimidina/química , Biosíntesis de Proteínas , Pirimidinas/química , ARN Mensajero/química , Ribonucleoproteínas/metabolismo , Células HEK293 , Humanos , Diana Mecanicista del Complejo 1 de la Rapamicina/química , Proteína de Unión al Tracto de Polipirimidina/genética , ARN Mensajero/genética , Transcriptoma , Antígeno SS-B
8.
J Exp Bot ; 73(20): 7016-7025, 2022 11 15.
Artículo en Inglés | MEDLINE | ID: mdl-35770874

RESUMEN

mRNA translation is the growth rate-limiting step in genome expression. Target of rapamycin (TOR) evolved a central regulatory role in eukaryotes as a signaling hub that monitors nutrient availability to maintain homeostasis and promote growth, largely by increasing the rate of translation initiation and protein synthesis. The dynamic pathways engaged by TOR to regulate translation remain debated even in well-studied yeast and mammalian models, however, despite decades of intense investigation. Recent studies have firmly established that TOR also regulates mRNA translation in plants through conserved mechanisms, such as the TOR-LARP1-5'TOP signaling axis, and through pathways specific to plants. Here, we review recent advances in our understanding of the regulation of mRNA translation in plants by TOR.


Asunto(s)
Plantas , Sirolimus , Plantas/genética , Plantas/metabolismo , ARN Mensajero/metabolismo , Transducción de Señal/genética , Sirolimus/metabolismo
9.
Ann Hepatol ; 27(2): 100678, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35093599

RESUMEN

INTRODUCTION AND OBJECTIVES: Circular RNA La Ribonucleoprotein 1B (circ-LARP1B) was reported to serve as an oncogene in many types of cancers. Radiotherapy (RT) is an important element of the multimodal treatment concept in malignancies. Here, this work aimed to investigate the role of circ-LARP1B in the tumorigenesis and radiosensitivity of hepatocellular carcinoma (HCC). PATIENTS OR MATERIALS AND METHODS: Quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot were used to detect the expression of genes and proteins. In vitro experiments were conducted using cell counting Kit-8 (CCK-8), colony formation, EDU, transwell, and tube formation assays, respectively. Dual-luciferase reporter assay was employed to identify the target relationship between miR-578 and circ-LARP1B or IGF1R (insulin-like growth factor 1 receptor). In vivo assay was performed using murine xenograft model. RESULTS: Circ-LARP1B was highly expressed in HCC tissues and cells, and high expression of circ-LARP1B was closely associated with poor prognosis. Functional experiments demonstrated that circ-LARP1B silencing impaired cell proliferation, invasion, angiogenesis and reduced radioresistance in vitro. Mechanistically, circ-LARP1B could competitively bind with miR-578 to relieve the repression of miR-578 on the expression of its target gene IGF1R. Further rescue assay confirmed that miR-578 inhibition reversed the inhibitory effects of circ-LARP1B knockdown on HCC cell malignant phenotypes and radioresistance. Moreover, miR-578 overexpression restrained tumorigenicity and enhanced radiosensitivity in HCC cells, which were attenuated by IGF1R up-regulation. Besides that, circ-LARP1B knockdown impeded tumor growth and enhanced irradiation sensitivity in HCC in vivo. CONCLUSIONS: Circ-LARP1B knockdown restrained HCC tumorigenicity and enhanced radiosensitivity by regulating miR-578/IGF1R axis, providing a new target for the treatment of HCC.


Asunto(s)
Carcinoma Hepatocelular , Neoplasias Hepáticas , MicroARNs , Animales , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/metabolismo , Carcinoma Hepatocelular/radioterapia , Línea Celular Tumoral , Proliferación Celular/genética , Regulación Neoplásica de la Expresión Génica , Humanos , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/metabolismo , Neoplasias Hepáticas/radioterapia , Ratones , MicroARNs/genética , MicroARNs/metabolismo , ARN Circular/genética , Tolerancia a Radiación/genética , Receptor IGF Tipo 1/genética , Receptor IGF Tipo 1/metabolismo
10.
World J Surg Oncol ; 20(1): 108, 2022 Apr 02.
Artículo en Inglés | MEDLINE | ID: mdl-35365169

RESUMEN

BACKGROUND: Lung cancer is a common respiratory system disease caused by multiple factors. Circular RNAs (circRNAs) play vital roles in tumorigenesis, including lung cancer. This study aimed to clarify the role and underlying molecular mechanisms of circ_0047921 in lung cancer. METHODS: Real-time quantitative polymerase chain reaction (RT-qPCR) was used to assess the expression levels of circ_0047921, La-related protein 1 (LARP1), and miR-1287-5p. Cell proliferation was analyzed by CCK-8 and EdU assays. Transwell assay was used to assess migration and invasion. Western blot assay was employed to quantify protein expression. Glycolysis ability of cell was determined by measuring glucose consumption and lactate production with matched kits. The relationship between miR-1287-5p and circ_0047921 or LARP1 was confirmed by dual-luciferase reporter assay. In addition, a xenograft model was established to clarify the functional role of circ_0047921 in vivo. RESULTS: Circ_0047921 was highly expressed in lung cancer tissues and cells. Circ_0047921 downregulation repressed proliferation, migration, invasion, epithelial-mesenchymal transition (EMT) and glycolysis in lung cancer cells. Circ_0047921 targeted miR-1287-5p to deplete miR-1287-5p expression. The effects caused by circ_0047921 downregulation were reversed by miR-1287-5p inhibition. In addition, LARP1 was a target of miR-1287-5p, and circ_0047921 could directly interact with miR-1287-5p to increase the expression of LARP1. The effects caused by circ_0047921 downregulation were also reversed by LARP1 overexpression. Circ_0047921 silencing impeded the growth of tumor in vivo. CONCLUSION: Circ_0047921 was overexpressed in lung cancer, and circ_0047921 targeted miR-1287-5p to modulate LARP1 expression, thereby facilitating the development of lung cancer. TRIAL REGISTRATION: The present study was approved by the ethical review committee of The First People's Hospital of Chenzhou, Southern Medical University with reference no. 20210106.


Asunto(s)
Neoplasias Pulmonares , MicroARNs , Línea Celular Tumoral , Proliferación Celular , Regulación Neoplásica de la Expresión Génica , Glucólisis , Humanos , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/patología , MicroARNs/genética , MicroARNs/metabolismo
11.
Genes Dev ; 28(4): 357-71, 2014 Feb 15.
Artículo en Inglés | MEDLINE | ID: mdl-24532714

RESUMEN

The mammalian target of rapamycin (mTOR) promotes cell growth and proliferation by promoting mRNA translation and increasing the protein synthetic capacity of the cell. Although mTOR globally promotes translation by regulating the mRNA 5' cap-binding protein eIF4E (eukaryotic initiation factor 4E), it also preferentially regulates the translation of certain classes of mRNA via unclear mechanisms. To help fill this gap in knowledge, we performed a quantitative proteomic screen to identify proteins that associate with the mRNA 5' cap in an mTOR-dependent manner. Using this approach, we identified many potential regulatory factors, including the putative RNA-binding protein LARP1 (La-related protein 1). Our results indicate that LARP1 associates with actively translating ribosomes via PABP and that LARP1 stimulates the translation of mRNAs containing a 5' terminal oligopyrimidine (TOP) motif, encoding for components of the translational machinery. We found that LARP1 associates with the mTOR complex 1 (mTORC1) and is required for global protein synthesis as well as cell growth and proliferation. Together, these data reveal important molecular mechanisms involved in TOP mRNA translation and implicate LARP1 as an important regulator of cell growth and proliferation.


Asunto(s)
Autoantígenos/metabolismo , Regulación de la Expresión Génica , Proteómica , Pirimidinas/metabolismo , ARN Mensajero/genética , Ribonucleoproteínas/metabolismo , Proteínas Adaptadoras Transductoras de Señales/metabolismo , Animales , Autoantígenos/genética , Línea Celular , Línea Celular Tumoral , Células Cultivadas , Células HEK293 , Humanos , Ratones , Proteínas de Unión a Caperuzas de ARN/metabolismo , Ribonucleoproteínas/genética , Transducción de Señal , Serina-Treonina Quinasas TOR/metabolismo , Antígeno SS-B
12.
RNA Biol ; 18(2): 248-258, 2021 02.
Artículo en Inglés | MEDLINE | ID: mdl-31601159

RESUMEN

La-Related Protein 1 (LARP1) is an RNA-binding protein that regulates the stability and translation of mRNAs encoding the translation machinery, including ribosomal proteins and translation factors. These mRNAs are characterized by a 5'-terminal oligopyrimidine (TOP) motif that coordinates their temporal and stoichiometric expression. While LARP1 represses TOP mRNA translation via the C-terminal DM15 region, the role of the N-terminal La-Module in the recognition and translational regulation of TOP mRNAs remains elusive. Herein we show that the LARP1 La-Module also binds TOP motifs, although in a cap-independent manner. We also demonstrate that it recognizes poly(A) RNA. Further, our data reveal that the LARP1 La-Module can simultaneously engage TOP motifs and poly(A) RNA. These results evoke an intriguing molecular mechanism whereby LARP1 could regulate translation and stabilization of TOP transcripts.


Asunto(s)
Autoantígenos/química , Autoantígenos/metabolismo , Sitios de Unión , Dominios y Motivos de Interacción de Proteínas , ARN Mensajero/química , ARN Mensajero/metabolismo , Ribonucleoproteínas/química , Ribonucleoproteínas/metabolismo , Regiones no Traducidas 5' , Autoantígenos/genética , Regulación de la Expresión Génica , Humanos , Modelos Biológicos , Motivos de Nucleótidos , Poli A , Unión Proteica , Procesamiento Proteico-Postraduccional , Procesamiento Postranscripcional del ARN , ARN Mensajero/genética , Ribonucleoproteínas/genética , Antígeno SS-B
13.
RNA Biol ; 18(2): 237-247, 2021 02.
Artículo en Inglés | MEDLINE | ID: mdl-32286153

RESUMEN

LARP1 is an oncogenic RNA-binding protein required for ribosome biogenesis and cancer cell survival. From published in vitro studies, there is disparity over which of two different LARP1 protein isoforms (termed the long LI-LARP1 and short SI-LARP1) is the canonical. Here, after conducting a series of biochemical and cellular assays, we conclude that LI-LARP1 (NM_033551.3 > NP_056130.2) is the dominantly expressed form. We observe that SI-LARP1 (NM_015315.5> NP_056130.2) is epigenetically repressed and that this repression is evolutionarily conserved in all but a small subclade of mammalian species. As with other LARP family members, there are multiple potential LARP1 mRNA isoforms that appear to be censored within the nucleus. The capacity of the cell to modulate splicing and expression of these apparently 'redundant' mRNAs hints at contextually specific mechanisms of LARP1 expression.


Asunto(s)
Autoantígenos/genética , Regulación Neoplásica de la Expresión Génica , Ribonucleoproteínas/genética , Empalme Alternativo , Secuencia de Aminoácidos , Autoantígenos/química , Autoantígenos/metabolismo , Línea Celular Tumoral , Metilación de ADN , Silenciador del Gen , Humanos , Familia de Multigenes , Especificidad de Órganos , Regiones Promotoras Genéticas , Unión Proteica , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , ARN/genética , ARN/metabolismo , Proteínas de Unión al ARN/química , Proteínas de Unión al ARN/genética , Proteínas de Unión al ARN/metabolismo , Ribonucleoproteínas/química , Ribonucleoproteínas/metabolismo , Antígeno SS-B
14.
RNA Biol ; 18(2): 207-217, 2021 02.
Artículo en Inglés | MEDLINE | ID: mdl-32233986

RESUMEN

The RNA-binding protein LARP1 has generated interest in recent years for its role in the mTOR signalling cascade and its regulation of terminal oligopyrimidine (TOP) mRNA translation. Paradoxically, some scientists have shown that LARP1 represses TOP translation while others that LARP1 activates it. Here, we present opinions from four leading scientists in the field to discuss these and other contradictory findings.


Asunto(s)
Autoantígenos/metabolismo , Proteínas de Unión al ARN/metabolismo , Ribonucleoproteínas/metabolismo , Animales , Autoantígenos/química , Autoantígenos/genética , Sitios de Unión , Proteínas Portadoras , Regulación de la Expresión Génica , Humanos , Familia de Multigenes , Unión Proteica , Dominios y Motivos de Interacción de Proteínas , ARN/química , ARN/metabolismo , División del ARN , Proteínas de Unión al ARN/química , Proteínas de Unión al ARN/genética , Ribonucleoproteínas/química , Ribonucleoproteínas/genética , Transducción de Señal , Especificidad por Sustrato , Antígeno SS-B
15.
J Biol Chem ; 290(26): 15996-6020, 2015 Jun 26.
Artículo en Inglés | MEDLINE | ID: mdl-25940091

RESUMEN

The mammalian target of rapamycin complex 1 (mTORC1) is a critical regulator of protein synthesis. The best studied targets of mTORC1 in translation are the eukaryotic initiation factor-binding protein 1 (4E-BP1) and ribosomal protein S6 kinase 1 (S6K1). In this study, we identify the La-related protein 1 (LARP1) as a key novel target of mTORC1 with a fundamental role in terminal oligopyrimidine (TOP) mRNA translation. Recent genome-wide studies indicate that TOP and TOP-like mRNAs compose a large portion of the mTORC1 translatome, but the mechanism by which mTORC1 controls TOP mRNA translation is incompletely understood. Here, we report that LARP1 functions as a key repressor of TOP mRNA translation downstream of mTORC1. Our data show the following: (i) LARP1 associates with mTORC1 via RAPTOR; (ii) LARP1 interacts with TOP mRNAs in an mTORC1-dependent manner; (iii) LARP1 binds the 5'TOP motif to repress TOP mRNA translation; and (iv) LARP1 competes with the eukaryotic initiation factor (eIF) 4G for TOP mRNA binding. Importantly, from a drug resistance standpoint, our data also show that reducing LARP1 protein levels by RNA interference attenuates the inhibitory effect of rapamycin, Torin1, and amino acid deprivation on TOP mRNA translation. Collectively, our findings demonstrate that LARP1 functions as an important repressor of TOP mRNA translation downstream of mTORC1.


Asunto(s)
Autoantígenos/metabolismo , Regulación hacia Abajo , Glicoproteínas de Membrana/metabolismo , Biosíntesis de Proteínas , ARN Mensajero/genética , Ribonucleoproteínas/metabolismo , Proteínas Adaptadoras Transductoras de Señales/genética , Proteínas Adaptadoras Transductoras de Señales/metabolismo , Autoantígenos/genética , Factor 4E Eucariótico de Iniciación/genética , Factor 4E Eucariótico de Iniciación/metabolismo , Humanos , Diana Mecanicista del Complejo 1 de la Rapamicina , Glicoproteínas de Membrana/genética , Complejos Multiproteicos/genética , Complejos Multiproteicos/metabolismo , Unión Proteica , ARN Largo no Codificante , ARN Mensajero/química , ARN Mensajero/metabolismo , Proteína Reguladora Asociada a mTOR , Ribonucleoproteínas/genética , Serina-Treonina Quinasas TOR/genética , Serina-Treonina Quinasas TOR/metabolismo , Antígeno SS-B
16.
Biochim Biophys Acta ; 1849(7): 801-11, 2015 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-25234618

RESUMEN

Cells encountering hostile growth conditions, like those residing in the middle of a newly developing solid tumor, conserve resources and energy by downregulating protein synthesis. One mechanism in this response is the translational repression of multiple mRNAs that encode components of the translational apparatus. This coordinated translational control is carried through a common cis-regulatory element, the 5' Terminal OligoPyrimidine motif (5'TOP), after which these mRNAs are referred to as TOP mRNAs. Subsequent to the initial structural and functional characterization of members of this family, the research of TOP mRNAs has progressed in three major directions: a) delineating the landscape of the family; b) establishing the pathways that transduce stress cues into selective translational repression; and c) attempting to decipher the most proximal trans-acting factor(s) and defining its mode of action--a repressor or activator. The present chapter critically reviews the development in these three avenues of research with a special emphasis on the two "top secrets" of the TOP mRNA family: the scope of its members and the identity of the proximal cellular regulator(s). This article is part of a Special Issue entitled: Translation and Cancer.


Asunto(s)
Regiones no Traducidas 5' , Neoplasias/metabolismo , Conformación de Ácido Nucleico , ARN Neoplásico/metabolismo , Secuencias Reguladoras de Ácido Ribonucleico , Animales , Humanos , Neoplasias/genética , Neoplasias/patología , ARN Neoplásico/química , ARN Neoplásico/genética
17.
Tumour Biol ; 37(11): 14585-14594, 2016 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-27614686

RESUMEN

This study investigated the significance of La-related protein 1 (LARP1) in the development and progression of colorectal cancer (CRC). Quantitative real-time polymerase chain reaction and Western blot analyses were carried out to determine the mRNA and protein expression of LARP1 in CRC tumor tissues and paired adjacent normal mucosa. The expression of LARP1 was upregulated in CRC. Immunohistochemical analysis using tissue microarray was performed. A positive correlation between LARP1 and proliferating cell nuclear antigen (PCNA) in the area of proliferation was observed using the Spearman's correlation coefficient test (r = 0.332, P < 0.01). The elevated expression of LARP1 significantly correlated with T stage (P = 0.02), N stage (P = 0.006), M stage (P < 0.001), American Joint Committee on Cancer (AJCC) stage (P = 0.04), differentiation rank (P < 0.001), and PCNA level (P < 0.001). In addition, the inhibitory effect of LARP1 knockdown on CRC cell proliferation was demonstrated using Cell Counting Kit-8 (CCK8) and colony-forming cell (CFC) assays. Multivariate analysis showed that LARP1 was an independent prognostic factor for overall survival (OS; hazard rate (HR) = 0.244; 95 % confidence interval (CI), 0.078-0.769; P = 0.016) and disease-free survival (DFS; HR = 0.281; 95 % CI, 0.086-0.917; P = 0.035) in CRC patients. LARP1 plays an important role in the proliferation of colorectal cancer and represents a new prognostic indicator.


Asunto(s)
Autoantígenos/biosíntesis , Autoantígenos/genética , Neoplasias Colorrectales/patología , Regulación Neoplásica de la Expresión Génica , Antígeno Nuclear de Célula en Proliferación/biosíntesis , ARN Mensajero/biosíntesis , Ribonucleoproteínas/biosíntesis , Ribonucleoproteínas/genética , Adulto , Anciano , Anciano de 80 o más Años , Biomarcadores de Tumor/biosíntesis , Línea Celular Tumoral , Proliferación Celular , Neoplasias Colorrectales/mortalidad , Supervivencia sin Enfermedad , Femenino , Humanos , Inmunohistoquímica , Masculino , Persona de Mediana Edad , Estadificación de Neoplasias , Pronóstico , Interferencia de ARN , ARN Interferente Pequeño/genética , Reacción en Cadena en Tiempo Real de la Polimerasa , Análisis de Matrices Tisulares , Antígeno SS-B
18.
Open Life Sci ; 19(1): 20220806, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38283117

RESUMEN

This study aimed to clarify the role of la-related protein 1 (LARP1) in cell cycle progression and metastatic behavior of cultured gastric carcinoma (GC) cells. To do that, LARP1 expression was detected in clinical GC tissues and cell lines using quantitative real-time polymerase chain reaction (qRT-PCR) and western blotting. The cell viability, apoptosis, cell cycle, migration, invasion, and cell growth were examined using a Cell Counting Kit-8, Annexin V-FITC staining, propidium iodide staining, Transwell migration and invasion assays, and colony formation assays after LARP1 knockdown. Phosphatidyl inositol 3-kinase (PI3K) and AKT1 mRNA and protein expression levels of PI3K, p-AKT1, AKT1, p-BAD, p-mTOR, and p21 in si-LARP1 transfected GC cells were determined using qRT-PCR and western blotting. Here, we've shown that LARP1 expression was upregulated in human GC tissues and KATO III cells. LARP1 knockdown inhibited GC cell proliferation, cell cycle progression, migration, invasion, and colony formation and promoted apoptosis. In si-LARP1-transfected KATO III cells, the mRNA expression levels of PI3K and AKT1, PI3K protein expression, and the p-AKT1/AKT1 ratio were significantly suppressed. p-mTOR and p-BAD were significantly decreased, whereas p21 was significantly increased in si-LARP1-transfected KATO III cells. In conclusion LARP1 knockdown induces apoptosis and inhibits cell cycle progression and metastatic behavior via PI3K/AKT1 signaling in GC cells.

19.
Biomol NMR Assign ; 18(1): 111-118, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38691336

RESUMEN

Human La-related protein 1 (HsLARP1) is involved in post-transcriptional regulation of certain 5' terminal oligopyrimidine (5'TOP) mRNAs as well as other mRNAs and binds to both the 5'TOP motif and the 3'-poly(A) tail of certain mRNAs. HsLARP1 is heavily involved in cell proliferation, cell cycle defects, and cancer, where HsLARP1 is significantly upregulated in malignant cells and tissues. Like all LARPs, HsLARP1 contains a folded RNA binding domain, the La motif (LaM). Our current understanding of post-transcriptional regulation that emanates from the intricate molecular framework of HsLARP1 is currently limited to small snapshots, obfuscating our understanding of the full picture on HsLARP1 functionality in post-transcriptional events. Here, we present the nearly complete resonance assignment of the LaM of HsLARP1, providing a significant platform for future NMR spectroscopic studies.


Asunto(s)
Secuencias de Aminoácidos , Resonancia Magnética Nuclear Biomolecular , Humanos , Secuencia de Aminoácidos , Autoantígenos/química , Autoantígenos/metabolismo , Isótopos de Nitrógeno , Ribonucleoproteínas/química , Ribonucleoproteínas/metabolismo , Proteínas de Unión al ARN
20.
Biochim Biophys Acta Mol Basis Dis ; 1870(8): 167453, 2024 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-39111634

RESUMEN

Targeting the PI3K/mTOR pathway and modulating mitochondrial adaptation is expected to be a critical approach for cancer therapy. Although the regulation of mitochondria by the PI3K/mTOR pathway has been investigated, it is not well understood due to the complexity of its regulatory mechanisms. RNA-binding proteins (RBPs) selectively regulate gene expression through post-transcriptional modulation, playing a key role in cancer progression. LARP1, a downstream RBP of the mTOR pathway, is involved in mitochondria-mediated BCL-2 cell survival. Therefore, exploring the involvement of LARP1 in PI3K/mTOR-mediated translational regulation of mitochondria-associated proteins in ovarian cancer cells could help elucidate the role of mitochondria in the PI3K/mTOR pathway. We found that, unlike SKOV3 cells, the mitochondrial function of A2780 cells was not affected, which were insensitive to the dual PI3K/mTOR inhibitor PKI-402, suggesting that cell survival may be related to mitochondrial function. Knockdown of the LARP1 gene after PKI-402 treatment resulted in impaired mitochondrial function in A2780 cells, possibly due to decreased mRNA stability and reduced protein translation of the mitochondrial transcription initiation factor, TFB2M, and the respiratory chain complex II subunit, SDHB. LARP1 affects protein translation by binding to TFB2M mRNA, regulating mitochondrial DNA-encoded genes, or indirectly regulating the nuclear DNA-encoded SDHB gene, ultimately interfering with mitochondrial oxidative phosphorylation and leading to apoptosis. Therefore, LARP1 may be an important mediator in the PI3K/mTOR pathway for regulating mRNA translation and mitochondrial function. Targeting RBPs such as LARP1 downstream of the mTOR pathway may provide new insights and potential therapeutic approaches for ovarian cancer treatment.


Asunto(s)
Autoantígenos , Supervivencia Celular , Mitocondrias , Neoplasias Ováricas , Fosforilación Oxidativa , Fosfatidilinositol 3-Quinasas , Ribonucleoproteínas , Antígeno SS-B , Transducción de Señal , Serina-Treonina Quinasas TOR , Humanos , Serina-Treonina Quinasas TOR/metabolismo , Femenino , Neoplasias Ováricas/metabolismo , Neoplasias Ováricas/patología , Neoplasias Ováricas/genética , Mitocondrias/metabolismo , Autoantígenos/metabolismo , Autoantígenos/genética , Línea Celular Tumoral , Ribonucleoproteínas/metabolismo , Ribonucleoproteínas/genética , Fosfatidilinositol 3-Quinasas/metabolismo , Regulación Neoplásica de la Expresión Génica , Naftiridinas
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