Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 41
Filtrar
1.
Cell ; 179(5): 1222-1238.e17, 2019 11 14.
Artigo em Inglês | MEDLINE | ID: mdl-31730859

RESUMO

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.


Assuntos
Genes Modificadores , Mitocôndrias/genética , Mitocôndrias/patologia , Autoantígenos/metabolismo , Morte Celular/efeitos dos fármacos , Citosol/efeitos dos fármacos , Citosol/metabolismo , Complexo I de Transporte de Elétrons/metabolismo , Epistasia Genética/efeitos dos fármacos , Ferroptose/efeitos dos fármacos , Ferroptose/genética , Genoma , Glutationa Peroxidase/metabolismo , Glicólise/efeitos dos fármacos , Glicólise/genética , Humanos , Células K562 , Mitocôndrias/efeitos dos fármacos , Oligomicinas/toxicidade , Oxirredução , Fosforilação Oxidativa/efeitos dos fármacos , Via de Pentose Fosfato/efeitos dos fármacos , Via de Pentose Fosfato/genética , Espécies Reativas de Oxigênio/metabolismo , Ribonucleoproteínas/metabolismo , Antígeno SS-B
2.
Mol Cell ; 81(13): 2838-2850.e6, 2021 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-33989516

RESUMO

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.


Assuntos
Autoantígenos/genética , COVID-19/genética , RNA Viral/genética , Ribonucleoproteínas/genética , SARS-CoV-2/genética , COVID-19/virologia , Coronavirus Humano OC43/genética , Coronavirus Humano OC43/patogenicidade , Células HEK293 , Interações Hospedeiro-Patógeno/genética , Humanos , Ligação Proteica/genética , Mapas de Interação de Proteínas/genética , Proteínas de Ligação a RNA/genética , SARS-CoV-2/patogenicidade , Serina-Treonina Quinases TOR/genética , Fatores de Transcrição/genética , Transcriptoma/genética , Proteínas com Motivo Tripartido/genética , Ubiquitina-Proteína Ligases/genética , Replicação Viral/genética , Antígeno SS-B
3.
Mol Cell ; 73(6): 1127-1137.e5, 2019 03 21.
Artigo em Inglês | MEDLINE | ID: mdl-30772175

RESUMO

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.


Assuntos
Replicação do DNA , DNA Mitocondrial/genética , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/enzimologia , Mitocôndrias/enzimologia , Membranas Mitocondriais/enzimologia , Proteínas Mitocondriais/biossíntese , Mutação , Oócitos/enzimologia , Proteínas Serina-Treonina Quinases/metabolismo , Animais , Animais Geneticamente Modificados , DNA Mitocondrial/biossíntese , Proteínas de Drosophila/genética , Drosophila melanogaster/genética , Feminino , Padrões de Herança , Mitocôndrias/genética , Proteínas Mitocondriais/genética , Oogênese , Biogênese de Organelas , Fosforilação , Proteínas Serina-Treonina Quinases/genética , Estabilidade Proteica , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo
4.
RNA Biol ; 21(1): 7-16, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-39016322

RESUMO

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].


Assuntos
Poli A , Ligação Proteica , Ribonucleoproteínas , Antígeno SS-B , Ribonucleoproteínas/metabolismo , Ribonucleoproteínas/química , Ribonucleoproteínas/genética , Poli A/metabolismo , Poli A/química , Humanos , Modelos Moleculares , Sítios de Ligação , Autoantígenos/metabolismo , Autoantígenos/química , Autoantígenos/genética , Cristalografia por Raios X , Domínios Proteicos , GMP Cíclico/metabolismo , GMP Cíclico/análogos & derivados , GMP Cíclico/química , RNA Mensageiro/metabolismo , RNA Mensageiro/química , RNA Mensageiro/genética
5.
J Biol Chem ; 298(9): 102277, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-35863436

RESUMO

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.


Assuntos
Aminoácidos , Biossíntese de Proteínas , Proteínas Serina-Treonina Quinases , Sequência de Oligopirimidina na Região 5' Terminal do RNA , RNA Mensageiro , Proteínas de Ligação a RNA , Fator 4 Ativador da Transcrição/genética , Fator 4 Ativador da Transcrição/metabolismo , Aminoácidos/metabolismo , Animais , Técnicas de Cultura de Células , Imunoprecipitação da Cromatina , Fator de Iniciação 4E em Eucariotos/metabolismo , Fibroblastos , Alvo Mecanístico do Complexo 1 de Rapamicina/metabolismo , Camundongos , Camundongos Knockout , Proteínas Serina-Treonina Quinases/genética , Proteínas Serina-Treonina Quinases/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Proteínas de Ligação a RNA/genética , Proteínas de Ligação a RNA/metabolismo
6.
Cell Mol Life Sci ; 79(3): 147, 2022 Feb 23.
Artigo em Inglês | MEDLINE | ID: mdl-35195778

RESUMO

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.


Assuntos
Autoantígenos/metabolismo , Carcinogênese/metabolismo , Neoplasias Colorretais/metabolismo , Retroalimentação Fisiológica , Proteínas Proto-Oncogênicas c-myc/metabolismo , Ribonucleoproteínas/metabolismo , Regiões 3' não Traduzidas , Animais , Autoantígenos/genética , Carcinogênese/genética , Proliferação de Células/genética , Neoplasias Colorretais/genética , Neoplasias Colorretais/patologia , Regulação Neoplásica da Expressão Gênica , Células HCT116 , Humanos , Camundongos , Oncogenes , Ribonucleoproteínas/genética , Transcriptoma/genética , Transfecção , Carga Tumoral/genética , Ensaios Antitumorais Modelo de Xenoenxerto , Antígeno SS-B
7.
Proc Natl Acad Sci U S A ; 117(10): 5319-5328, 2020 03 10.
Artigo em Inglês | MEDLINE | ID: mdl-32094190

RESUMO

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.


Assuntos
Autoantígenos/metabolismo , Motivos de Nucleotídeos , Proteína de Ligação a Regiões Ricas em Polipirimidinas/química , Biossíntese de Proteínas , Pirimidinas/química , RNA Mensageiro/química , Ribonucleoproteínas/metabolismo , Células HEK293 , Humanos , Alvo Mecanístico do Complexo 1 de Rapamicina/química , Proteína de Ligação a Regiões Ricas em Polipirimidinas/genética , RNA Mensageiro/genética , Transcriptoma , Antígeno SS-B
8.
J Exp Bot ; 73(20): 7016-7025, 2022 11 15.
Artigo em Inglês | MEDLINE | ID: mdl-35770874

RESUMO

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.


Assuntos
Plantas , Sirolimo , Plantas/genética , Plantas/metabolismo , RNA Mensageiro/metabolismo , Transdução de Sinais/genética , Sirolimo/metabolismo
9.
Ann Hepatol ; 27(2): 100678, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35093599

RESUMO

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.


Assuntos
Carcinoma Hepatocelular , Neoplasias Hepáticas , MicroRNAs , Animais , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/metabolismo , Carcinoma Hepatocelular/radioterapia , Linhagem Celular Tumoral , Proliferação de Células/genética , Regulação Neoplásica da Expressão Gênica , Humanos , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/metabolismo , Neoplasias Hepáticas/radioterapia , Camundongos , MicroRNAs/genética , MicroRNAs/metabolismo , RNA Circular/genética , Tolerância a Radiação/genética , Receptor IGF Tipo 1/genética , Receptor IGF Tipo 1/metabolismo
10.
World J Surg Oncol ; 20(1): 108, 2022 Apr 02.
Artigo em Inglês | MEDLINE | ID: mdl-35365169

RESUMO

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.


Assuntos
Neoplasias Pulmonares , MicroRNAs , Linhagem Celular Tumoral , Proliferação de Células , Regulação Neoplásica da Expressão Gênica , Glicólise , Humanos , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/patologia , MicroRNAs/genética , MicroRNAs/metabolismo
11.
Genes Dev ; 28(4): 357-71, 2014 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-24532714

RESUMO

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.


Assuntos
Autoantígenos/metabolismo , Regulação da Expressão Gênica , Proteômica , Pirimidinas/metabolismo , RNA Mensageiro/genética , Ribonucleoproteínas/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Animais , Autoantígenos/genética , Linhagem Celular , Linhagem Celular Tumoral , Células Cultivadas , Células HEK293 , Humanos , Camundongos , Proteínas de Ligação ao Cap de RNA/metabolismo , Ribonucleoproteínas/genética , Transdução de Sinais , Serina-Treonina Quinases TOR/metabolismo , Antígeno SS-B
12.
RNA Biol ; 18(2): 248-258, 2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-31601159

RESUMO

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.


Assuntos
Autoantígenos/química , Autoantígenos/metabolismo , Sítios de Ligação , Domínios e Motivos de Interação entre Proteínas , RNA Mensageiro/química , RNA Mensageiro/metabolismo , Ribonucleoproteínas/química , Ribonucleoproteínas/metabolismo , Regiões 5' não Traduzidas , Autoantígenos/genética , Regulação da Expressão Gênica , Humanos , Modelos Biológicos , Motivos de Nucleotídeos , Poli A , Ligação Proteica , Processamento de Proteína Pós-Traducional , Processamento Pós-Transcricional do RNA , RNA Mensageiro/genética , Ribonucleoproteínas/genética , Antígeno SS-B
13.
RNA Biol ; 18(2): 237-247, 2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-32286153

RESUMO

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.


Assuntos
Autoantígenos/genética , Regulação Neoplásica da Expressão Gênica , Ribonucleoproteínas/genética , Processamento Alternativo , Sequência de Aminoácidos , Autoantígenos/química , Autoantígenos/metabolismo , Linhagem Celular Tumoral , Metilação de DNA , Inativação Gênica , Humanos , Família Multigênica , Especificidade de Órgãos , Regiões Promotoras Genéticas , Ligação Proteica , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , RNA/genética , RNA/metabolismo , Proteínas de Ligação a RNA/química , Proteínas de Ligação a RNA/genética , Proteínas de Ligação a RNA/metabolismo , Ribonucleoproteínas/química , Ribonucleoproteínas/metabolismo , Antígeno SS-B
14.
RNA Biol ; 18(2): 207-217, 2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-32233986

RESUMO

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.


Assuntos
Autoantígenos/metabolismo , Proteínas de Ligação a RNA/metabolismo , Ribonucleoproteínas/metabolismo , Animais , Autoantígenos/química , Autoantígenos/genética , Sítios de Ligação , Proteínas de Transporte , Regulação da Expressão Gênica , Humanos , Família Multigênica , Ligação Proteica , Domínios e Motivos de Interação entre Proteínas , RNA/química , RNA/metabolismo , Clivagem do RNA , Proteínas de Ligação a RNA/química , Proteínas de Ligação a RNA/genética , Ribonucleoproteínas/química , Ribonucleoproteínas/genética , Transdução de Sinais , Especificidade por Substrato , Antígeno SS-B
15.
J Biol Chem ; 290(26): 15996-6020, 2015 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-25940091

RESUMO

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.


Assuntos
Autoantígenos/metabolismo , Regulação para Baixo , Glicoproteínas de Membrana/metabolismo , Biossíntese de Proteínas , RNA Mensageiro/genética , Ribonucleoproteínas/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/genética , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Autoantígenos/genética , Fator de Iniciação 4E em Eucariotos/genética , Fator de Iniciação 4E em Eucariotos/metabolismo , Humanos , Alvo Mecanístico do Complexo 1 de Rapamicina , Glicoproteínas de Membrana/genética , Complexos Multiproteicos/genética , Complexos Multiproteicos/metabolismo , Ligação Proteica , RNA Longo não Codificante , RNA Mensageiro/química , RNA Mensageiro/metabolismo , Proteína Regulatória Associada a mTOR , Ribonucleoproteínas/genética , Serina-Treonina Quinases TOR/genética , Serina-Treonina Quinases TOR/metabolismo , Antígeno SS-B
16.
Biochim Biophys Acta ; 1849(7): 801-11, 2015 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-25234618

RESUMO

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.


Assuntos
Regiões 5' não Traduzidas , Neoplasias/metabolismo , Conformação de Ácido Nucleico , RNA Neoplásico/metabolismo , Sequências Reguladoras de Ácido Ribonucleico , Animais , Humanos , Neoplasias/genética , Neoplasias/patologia , RNA Neoplásico/química , RNA Neoplásico/genética
17.
Tumour Biol ; 37(11): 14585-14594, 2016 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-27614686

RESUMO

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.


Assuntos
Autoantígenos/biossíntese , Autoantígenos/genética , Neoplasias Colorretais/patologia , Regulação Neoplásica da Expressão Gênica , Antígeno Nuclear de Célula em Proliferação/biossíntese , RNA Mensageiro/biossíntese , Ribonucleoproteínas/biossíntese , Ribonucleoproteínas/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Biomarcadores Tumorais/biossíntese , Linhagem Celular Tumoral , Proliferação de Células , Neoplasias Colorretais/mortalidade , Intervalo Livre de Doença , Feminino , Humanos , Imuno-Histoquímica , Masculino , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Prognóstico , Interferência de RNA , RNA Interferente Pequeno/genética , Reação em Cadeia da Polimerase em Tempo Real , Análise Serial de Tecidos , Antígeno SS-B
18.
Open Life Sci ; 19(1): 20220806, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38283117

RESUMO

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.
Artigo em Inglês | MEDLINE | ID: mdl-38691336

RESUMO

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.


Assuntos
Motivos de Aminoácidos , Ressonância Magnética Nuclear Biomolecular , Humanos , Sequência de Aminoácidos , Autoantígenos/química , Autoantígenos/metabolismo , Isótopos de Nitrogênio , Ribonucleoproteínas/química , Ribonucleoproteínas/metabolismo , Proteínas de Ligação a RNA
20.
Thorac Cancer ; 14(22): 2187-2197, 2023 08.
Artigo em Inglês | MEDLINE | ID: mdl-37349870

RESUMO

BACKGROUND: The deregulation of circular RNA (circRNA) is widely reported in carcinogenesis. The purpose of this study was to investigate the role of circRNA-PDZ domain containing 8 (circ-PDZD8) in non-small cell lung cancer (NSCLC) progression. METHODS: The histological structure of tissues was identified by hematoxylin-eosin (HE) staining analysis. The expression levels of circ-PDZD8, miR-330-5p and la ribonucleoprotein 1 (LARP1) mRNA were ascertained by qPCR. Cell counting kit-8, colony formation, flow cytometry, and transwell assays were employed for functional analysis. Glutamine metabolism was monitored by glutamine consumption, alpha ketoglutarate (α-KG) level and adenosine triphosphate (ATP) level. A xenograft model was established to ascertain the role of circ-PDZD8 in vivo. The putative binding relationships were verified by dual-luciferase and RIP studies. RESULTS: Circ-PDZD8 expression was highly increased in NSCLC. Circ-PDZD8 knockdown inhibited cell growth, migratory capacity, invasiveness and glutamine metabolism but enhanced cell apoptosis in NSCLC cells. Circ-PDZD8 blocked miR-330-5p expression, and miR-330-5p inhibition overturned the effects of circ-PDZD8 absence. LARP1 targeted by miR-330-5p, and miR-330-5p upregulation-impaired cell growth, motility and glutamine metabolism were recovered by LARP1 overexpression. Circ-PDZD8 knockdown was also shown to impede solid tumor growth. CONCLUSION: Circ-PDZD8 promotes NSCLC cell growth and glutamine metabolism by increasing LARP1 via competitively targeting miR-330-5p.


Assuntos
Carcinoma Pulmonar de Células não Pequenas , Neoplasias Pulmonares , MicroRNAs , Humanos , Carcinoma Pulmonar de Células não Pequenas/genética , Glutamina , RNA Circular/genética , Neoplasias Pulmonares/genética , Proliferação de Células , MicroRNAs/genética , Linhagem Celular Tumoral , Proteínas Adaptadoras de Transdução de Sinal
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA