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1.
Elife ; 102021 Nov 17.
Artigo em Inglês | MEDLINE | ID: mdl-34787568

RESUMO

We performed a systematic analysis of the translation rate of tumor-infiltrating lymphocytes (TILs) and the microenvironment inputs affecting it, both in humans and in mice. Measurement of puromycin incorporation, a proxy of protein synthesis, revealed an increase of translating CD4+ and CD8+ cells in tumors, compared to normal tissues. High translation levels are associated with phospho-S6 labeling downstream of mTORC1 activation, whereas low levels correlate with hypoxic areas, in agreement with data showing that T cell receptor stimulation and hypoxia act as translation stimulators and inhibitors, respectively. Additional analyses revealed the specific phenotype of translating TILs. CD8+ translating cells have enriched expression of IFN-γ and CD-39, and reduced SLAMF6, pointing to a cytotoxic phenotype. CD4+ translating cells are mostly regulatory T cells (Tregs) with enriched levels of CTLA-4 and Ki67, suggesting an expanding immunosuppressive phenotype. In conclusion, the majority of translationally active TILs is represented by cytotoxic CD8+ and suppressive CD4+ Tregs, implying that other subsets may be largely composed by inactive bystanders.

2.
Neurology ; 2021 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-34649874

RESUMO

BACKGROUND AND OBJECTIVES: Autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS) is caused by mutations in SACS gene encoding sacsin, a huge multimodular protein of unknown function. More than 200 SACS mutations have been described worldwide to date. Since ARSACS presents phenotypic variability, previous empirical studies attempted to correlate the nature and position of SACS mutations with the age of onset or with disease severity, though not considering the effect of the various mutations on protein stability. In this work, we studied genotype-phenotype correlation in ARSACS at a functional level. METHODS: We analyzed a large set of skin fibroblasts derived from ARSACS patients, including both new and already published cases, carrying mutations of different type affecting diverse domains of the protein. RESULTS: We found that sacsin is almost absent in ARSACS patients, regardless of the nature of the mutation. As expected, we did not detect sacsin in patients with truncating mutations. Interestingly, we found it strikingly reduced or absent also in compound heterozygotes carrying diverse missense mutations. In this case, we excluded SACS mRNA decay, defective translation or faster post-translational degradation as possible causes of protein reduction. Conversely, our results demonstrate that nascent mutant sacsin protein undergoes cotranslational ubiquitination and degradation. DISCUSSION: Our results provide one mechanistic explanation for the lack of genotype-phenotype correlation in ARSACS. We also propose a new and unambiguous criterion for ARSACS diagnosis, that is based on the evaluation of sacsin level. Finally, we identified preemptive degradation of a mutant protein as a novel cause of a human disease.

3.
Dev Cell ; 56(18): 2607-2622.e6, 2021 09 27.
Artigo em Inglês | MEDLINE | ID: mdl-34534458

RESUMO

Atg6Beclin 1 mediates autophagy and endosomal trafficking. We investigated how Atg6 influences replication stress. Combining genetic, genomic, metabolomic, and proteomic approaches, we found that the Vps34-Vps15-Atg6Beclin 1-Vps38UVRAG-phosphatydilinositol-3 phosphate (PtdIns(3)P) axis sensitizes cells to replication stress by favoring the degradation of plasma membrane amino acid (AA) transporters via endosomal trafficking and ESCRT proteins, while the PtdIns(3)P phosphatases Ymr1 and Inp53 promote survival to replication stress by reversing this process. An impaired AA uptake triggers activation of Gcn2, which attenuates protein synthesis by phosphorylating eIF2α. Mec1Atr-Rad53Chk1/Chk2 activation during replication stress further hinders translation efficiency by counteracting eIF2α dephosphorylation through Glc7PP1. AA shortage-induced hyperphosphorylation of eIF2α inhibits the synthesis of 65 stress response proteins, thus resulting in cell sensitization to replication stress, while TORC1 promotes cell survival. Our findings reveal an integrated network mediated by endosomal trafficking, translational control pathways, and checkpoint kinases linking AA availability to the response to replication stress.


Assuntos
Autofagia/fisiologia , Proteínas de Ciclo Celular/metabolismo , Dano ao DNA/fisiologia , Endossomos/metabolismo , Proteína Beclina-1/metabolismo , Fosforilação , Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Leveduras
4.
Nat Commun ; 12(1): 4878, 2021 08 12.
Artigo em Inglês | MEDLINE | ID: mdl-34385447

RESUMO

A postprandial increase of translation mediated by eukaryotic Initiation Factor 6 (eIF6) occurs in the liver. Its contribution to steatosis and disease is unknown. In this study we address whether eIF6-driven translation contributes to disease progression. eIF6 levels increase throughout the progression from Non-Alcoholic Fatty Liver Disease (NAFLD) to hepatocellular carcinoma. Reduction of eIF6 levels protects the liver from disease progression. eIF6 depletion blunts lipid accumulation, increases fatty acid oxidation (FAO) and reduces oncogenic transformation in vitro. In addition, eIF6 depletion delays the progression from NAFLD to hepatocellular carcinoma, in vivo. Mechanistically, eIF6 depletion reduces the translation of transcription factor C/EBPß, leading to a drop in biomarkers associated with NAFLD progression to hepatocellular carcinoma and preserves mitochondrial respiration due to the maintenance of an alternative mTORC1-eIF4F translational branch that increases the expression of transcription factor YY1. We provide proof-of-concept that in vitro pharmacological inhibition of eIF6 activity recapitulates the protective effects of eIF6 depletion. We hypothesize the existence of a targetable, evolutionarily conserved translation circuit optimized for lipid accumulation and tumor progression.


Assuntos
Carcinoma Hepatocelular/genética , Neoplasias Hepáticas/genética , Hepatopatia Gordurosa não Alcoólica/genética , Fatores de Iniciação de Peptídeos/genética , Biossíntese de Proteínas/genética , Animais , Proteína beta Intensificadora de Ligação a CCAAT/genética , Proteína beta Intensificadora de Ligação a CCAAT/metabolismo , Carcinoma Hepatocelular/metabolismo , Linhagem Celular , Transformação Celular Neoplásica/efeitos dos fármacos , Transformação Celular Neoplásica/genética , Transformação Celular Neoplásica/metabolismo , Clofazimina/farmacologia , Dieta Hiperlipídica/efeitos adversos , Progressão da Doença , Inativação Gênica , Humanos , Lipogênese/efeitos dos fármacos , Lipogênese/genética , Neoplasias Hepáticas/metabolismo , Masculino , Camundongos Endogâmicos C57BL , Camundongos Knockout , Hepatopatia Gordurosa não Alcoólica/metabolismo , Obesidade/etiologia , Obesidade/genética , Obesidade/metabolismo , Fatores de Iniciação de Peptídeos/antagonistas & inibidores , Fatores de Iniciação de Peptídeos/metabolismo
5.
Nat Immunol ; 22(6): 735-745, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-34017124

RESUMO

Regulatory T (Treg) cells are a barrier for tumor immunity and a target for immunotherapy. Using single-cell transcriptomics, we found that CD4+ T cells infiltrating primary and metastatic colorectal cancer and non-small-cell lung cancer are highly enriched for two subsets of comparable size and suppressor function comprising forkhead box protein P3+ Treg and eomesodermin homolog (EOMES)+ type 1 regulatory T (Tr1)-like cells also expressing granzyme K and chitinase-3-like protein 2. EOMES+ Tr1-like cells, but not Treg cells, were clonally related to effector T cells and were clonally expanded in primary and metastatic tumors, which is consistent with their proliferation and differentiation in situ. Using chitinase-3-like protein 2 as a subset signature, we found that the EOMES+ Tr1-like subset correlates with disease progression but is also associated with response to programmed cell death protein 1-targeted immunotherapy. Collectively, these findings highlight the heterogeneity of Treg cells that accumulate in primary tumors and metastases and identify a new prospective target for cancer immunotherapy.


Assuntos
Carcinoma Pulmonar de Células não Pequenas/imunologia , Hematopoiese Clonal/imunologia , Neoplasias Colorretais/imunologia , Neoplasias Pulmonares/imunologia , Linfócitos T Reguladores/imunologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Carcinoma Pulmonar de Células não Pequenas/genética , Carcinoma Pulmonar de Células não Pequenas/secundário , Carcinoma Pulmonar de Células não Pequenas/terapia , Diferenciação Celular/genética , Diferenciação Celular/imunologia , Proliferação de Células/genética , Quimioterapia Adjuvante/métodos , Quitinases/metabolismo , Colectomia , Colo/patologia , Colo/cirurgia , Neoplasias Colorretais/genética , Neoplasias Colorretais/patologia , Neoplasias Colorretais/terapia , Conjuntos de Dados como Assunto , Progressão da Doença , Resistencia a Medicamentos Antineoplásicos/imunologia , Feminino , Citometria de Fluxo , Fatores de Transcrição Forkhead/metabolismo , Regulação Neoplásica da Expressão Gênica/imunologia , Granzimas/metabolismo , Humanos , Inibidores de Checkpoint Imunológico/farmacologia , Inibidores de Checkpoint Imunológico/uso terapêutico , Estimativa de Kaplan-Meier , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/patologia , Neoplasias Pulmonares/terapia , Masculino , Pessoa de Meia-Idade , Cultura Primária de Células , Receptor de Morte Celular Programada 1/antagonistas & inibidores , RNA-Seq , Análise de Célula Única , Proteínas com Domínio T/metabolismo , Linfócitos T Reguladores/metabolismo
6.
Curr Biol ; 31(4): 892-899.e3, 2021 02 22.
Artigo em Inglês | MEDLINE | ID: mdl-33275890

RESUMO

The plant hormone auxin is a fundamental regulator of organ patterning and development that regulates gene expression via the canonical AUXIN RESPONSE FACTOR (ARF) and AUXIN/INDOLE-3-ACETIC ACID (Aux/IAA) combinatorial system. ARF and Aux/IAA factors interact, but at high auxin concentrations, the Aux/IAA transcriptional repressor is degraded, allowing ARF-containing complexes to activate gene expression. ARF5/MONOPTEROS (MP) is an important integrator of auxin signaling in Arabidopsis development and activates gene transcription in cells with elevated auxin levels. Here, we show that in ovules, MP is expressed in cells with low levels of auxin and can activate the expression of direct target genes. We identified and characterized a splice variant of MP that encodes a biologically functional isoform that lacks the Aux/IAA interaction domain. This MP11ir isoform was able to complement inflorescence, floral, and ovule developmental defects in mp mutants, suggesting that it was fully functional. Our findings describe a novel scenario in which ARF post-transcriptional regulation controls the formation of an isoform that can function as a transcriptional activator in regions of subthreshold auxin concentration.

7.
Cancer Res ; 80(21): 4693-4706, 2020 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-32963011

RESUMO

Multiple myeloma is a plasma cell neoplasm characterized by the production of unfolded immunoglobulins, which cause endoplasmic reticulum (ER) stress and sensitivity to proteasome inhibition. The genomic landscape of multiple myeloma is characterized by the loss of several genes rarely mutated in other cancers that may underline specific weaknesses of multiple myeloma cells. One of these is FAM46C that is lost in more than 10% of patients with multiple myeloma. We show here that FAM46C is part of a new complex containing the ER-associated protein FNDC3A, which regulates trafficking and secretion and, by impairing autophagy, exacerbates proteostatic stress. Reconstitution of FAM46C in multiple myeloma cells that had lost it induced apoptosis and ER stress. Apoptosis was preceded by an increase of intracellular aggregates, which was not linked to increased translation of IgG mRNA, but rather to impairment of autophagy. Biochemical analysis showed that FAM46C requires interaction with ER bound protein FNDC3A to reside in the cytoplasmic side of the ER. FNDC3A was lost in some multiple myeloma cell lines. Importantly, depletion of FNDC3A increased the fitness of FAM46C-expressing cells and expression of FNDC3A in cells that had lost it recapitulated the effects of FAM46C, inducing aggregates and apoptosis. FAM46C and FNDC3A formed a complex that modulates secretion routes, increasing lysosome exocytosis. The cellular landscape generated by FAM46C/FNDC3A expression predicted sensitivity to sphingosine kinase inhibition. These results suggest that multiple myeloma cells remodel their trafficking machinery to cope with ER stress. SIGNIFICANCE: This study identifies a new multiple myeloma-specific tumor suppressor complex that regulates autophagy and unconventional secretion, highlighting the sensitivity of multiple myeloma cells to the accumulation of protein aggregates.


Assuntos
Fibronectinas/metabolismo , Mieloma Múltiplo/patologia , Nucleotidiltransferases/metabolismo , Agregação Patológica de Proteínas/metabolismo , Animais , Autofagia/fisiologia , Genes Supressores de Tumor , Xenoenxertos , Humanos , Camundongos , Mieloma Múltiplo/genética , Mieloma Múltiplo/metabolismo , Nucleotidiltransferases/genética , Agregados Proteicos/fisiologia , Transporte Proteico/fisiologia , Proteínas Supressoras de Tumor/genética , Proteínas Supressoras de Tumor/metabolismo
8.
Dev Comp Immunol ; 109: 103697, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32330465

RESUMO

The transition from a naïve to an effector T cell is an essential event that requires metabolic reprogramming. We have recently demonstrated that the rapid metabolic changes that occur following stimulation of naïve T cells require the translation of preexisting mRNAs. Here, we provide evidence that translation regulates the metabolic asset of effector T cells. By performing ribosome profiling in human CD4+ Th1 cells, we show that the metabolism of glucose, fatty acids and pentose phosphates is regulated at the translational level. In Th1 cells, each pathway has at least one enzyme regulated at the translational level and selected enzymes have high translational efficiencies. mRNA expression does not predict protein expression. For instance, PKM2 mRNA is equally present in naïve T and Th1 cells, but the protein is abundant only in Th1. 5'-untranslated regions (UTRs) may partly account for this regulation. Overall we suggest that immunometabolism is controlled by translation.


Assuntos
Linfócitos T CD4-Positivos/metabolismo , Perfilação da Expressão Gênica/métodos , Redes e Vias Metabólicas/genética , Biossíntese de Proteínas/genética , Ribossomos/genética , Células Th1/metabolismo , Regiões 5' não Traduzidas/genética , Linfócitos T CD4-Positivos/citologia , Diferenciação Celular/genética , Células Cultivadas , Ontologia Genética , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Humanos , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , RNA-Seq/métodos , Ribossomos/metabolismo , Células Th1/citologia
9.
Cells ; 9(1)2020 01 10.
Artigo em Inglês | MEDLINE | ID: mdl-31936702

RESUMO

Eukaryotic initiation factor 6 (eIF6) is necessary for the nucleolar biogenesis of 60S ribosomes. However, most of eIF6 resides in the cytoplasm, where it acts as an initiation factor. eIF6 is necessary for maximal protein synthesis downstream of growth factor stimulation. eIF6 is an antiassociation factor that binds 60S subunits, in turn preventing premature 40S joining and thus the formation of inactive 80S subunits. It is widely thought that eIF6 antiassociation activity is critical for its function. Here, we exploited and improved our assay for eIF6 binding to ribosomes (iRIA) in order to screen for modulators of eIF6 binding to the 60S. Three compounds, eIFsixty-1 (clofazimine), eIFsixty-4, and eIFsixty-6 were identified and characterized. All three inhibit the binding of eIF6 to the 60S in the micromolar range. eIFsixty-4 robustly inhibits cell growth, whereas eIFsixty-1 and eIFsixty-6 might have dose- and cell-specific effects. Puromycin labeling shows that eIF6ixty-4 is a strong global translational inhibitor, whereas the other two are mild modulators. Polysome profiling and RT-qPCR show that all three inhibitors reduce the specific translation of well-known eIF6 targets. In contrast, none of them affect the nucleolar localization of eIF6. These data provide proof of principle that the generation of eIF6 translational modulators is feasible.


Assuntos
Fatores de Iniciação de Peptídeos/metabolismo , Biossíntese de Proteínas , Subunidades Ribossômicas Maiores de Eucariotos/metabolismo , Linhagem Celular , Nucléolo Celular/efeitos dos fármacos , Nucléolo Celular/metabolismo , Sobrevivência Celular , Ensaio de Imunoadsorção Enzimática , Humanos , Iniciação Traducional da Cadeia Peptídica/efeitos dos fármacos , Polirribossomos/efeitos dos fármacos , Polirribossomos/metabolismo , Ligação Proteica/efeitos dos fármacos , Puromicina/farmacologia , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Reprodutibilidade dos Testes
10.
Dev Biol ; 455(1): 100-111, 2019 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-31283922

RESUMO

During development, ribosome biogenesis and translation reach peak activities, due to impetuous cell proliferation. Current models predict that protein synthesis elevation is controlled by transcription factors and signalling pathways. Developmental models addressing translation factors overexpression effects are lacking. Eukaryotic Initiation Factor 6 (eIF6) is necessary for ribosome biogenesis and efficient translation. eIF6 is a single gene, conserved from yeasts to mammals, suggesting a tight regulation need. We generated a Drosophila melanogaster model of eIF6 upregulation, leading to a boost in general translation and the shut-down of the ecdysone biosynthetic pathway. Indeed, translation modulation in S2 cells showed that translational rate and ecdysone biosynthesis are inversely correlated. In vivo, eIF6-driven alterations delayed Programmed Cell Death (PCD), resulting in aberrant phenotypes, partially rescued by ecdysone administration. Our data show that eIF6 triggers a translation program with far-reaching effects on metabolism and development, stressing the driving and central role of translation.


Assuntos
Proteínas de Drosophila/genética , Drosophila melanogaster/genética , Ecdisona/biossíntese , Regulação da Expressão Gênica no Desenvolvimento , Fatores de Iniciação de Peptídeos/genética , Biossíntese de Proteínas/genética , Animais , Animais Geneticamente Modificados , Apoptose/genética , Linhagem Celular , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/crescimento & desenvolvimento , Drosophila melanogaster/metabolismo , Discos Imaginais/crescimento & desenvolvimento , Discos Imaginais/metabolismo , Fatores de Iniciação de Peptídeos/metabolismo , Ribossomos/genética , Ribossomos/metabolismo , Transdução de Sinais/genética , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo
12.
Front Genet ; 9: 533, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30498507

RESUMO

Ribosomes have been long considered as executors of the translational program. The fact that ribosomes can control the translation of specific mRNAs or entire cellular programs is often neglected. Ribosomopathies, inherited diseases with mutations in ribosomal factors, show tissue specific defects and cancer predisposition. Studies of ribosomopathies have paved the way to the concept that ribosomes may control translation of specific mRNAs. Studies in Drosophila and mice support the existence of heterogeneous ribosomes that differentially translate mRNAs to coordinate cellular programs. Recent studies have now shown that ribosomal activity is not only a critical regulator of growth but also of metabolism. For instance, glycolysis and mitochondrial function have been found to be affected by ribosomal availability. Also, ATP levels drop in models of ribosomopathies. We discuss findings highlighting the relevance of ribosome heterogeneity in physiological and pathological conditions, as well as the possibility that in rate-limiting situations, ribosomes may favor some translational programs. We discuss the effects of ribosome heterogeneity on cellular metabolism, tumorigenesis and aging. We speculate a scenario in which ribosomes are not only executors of a metabolic program but act as modulators.

14.
Mol Cell Biol ; 38(23)2018 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-30201806

RESUMO

The translational capability of ribosomes deprived of specific nonfundamental ribosomal proteins may be altered. Physiological mechanisms are scanty, and it is unclear whether free ribosomal proteins can cross talk with the signaling machinery. RACK1 (receptor for activated C kinase 1) is a highly conserved scaffold protein, located on the 40S subunit near the mRNA exit channel. RACK1 is involved in a variety of intracellular contexts, both on and off the ribosomes, acting as a receptor for proteins in signaling, such as the protein kinase C (PKC) family. Here we show that the binding of RACK1 to ribosomes is essential for full translation of capped mRNAs and efficient recruitment of eukaryotic initiation factor 4E (eIF4E). In vitro, when RACK1 is partially depleted, supplementing the ribosome machinery with wild-type RACK1 restores the translational capability, whereas the addition of a RACK1 mutant that is unable to bind ribosomes does not. Outside the ribosome, RACK1 has a reduced half-life. By accumulating in living cells, free RACK1 exerts an inhibitory phenotype, impairing cell cycle progression and repressing global translation. Here we present RACK1 binding to ribosomes as a crucial way to regulate translation, possibly through interaction with known partners on or off the ribosome that are involved in signaling.

15.
Cell Metab ; 28(6): 895-906.e5, 2018 12 04.
Artigo em Inglês | MEDLINE | ID: mdl-30197303

RESUMO

Naive T cells respond to T cell receptor (TCR) activation by leaving quiescence, remodeling metabolism, initiating expansion, and differentiating toward effector T cells. The molecular mechanisms coordinating the naive to effector transition are central to the functioning of the immune system, but remain elusive. Here, we discover that T cells fulfill this transitional process through translational control. Naive cells accumulate untranslated mRNAs encoding for glycolysis and fatty acid synthesis factors and possess a translational machinery poised for immediate protein synthesis. Upon TCR engagement, activation of the translational machinery leads to synthesis of GLUT1 protein to drive glucose entry. Subsequently, translation of ACC1 mRNA completes metabolic reprogramming toward an effector phenotype. Notably, inhibition of the eIF4F complex abrogates lymphocyte metabolic activation and differentiation, suggesting ACC1 to be a key regulatory node. Thus, our results demonstrate that translation is a direct mediator of T cell metabolism and indicate translation factors as targets for novel immunotherapeutic approaches.


Assuntos
Acetil-CoA Carboxilase/biossíntese , Linfócitos T CD4-Positivos/metabolismo , Ácidos Graxos/metabolismo , Transportador de Glucose Tipo 1/biossíntese , Glicólise , Receptores de Antígenos de Linfócitos T/metabolismo , Subpopulações de Linfócitos T/metabolismo , Linfócitos T CD4-Positivos/citologia , Diferenciação Celular , Proliferação de Células , Fator de Iniciação 4F em Eucariotos/antagonistas & inibidores , Humanos , Ativação Linfocitária , Biossíntese de Proteínas , Subpopulações de Linfócitos T/citologia
16.
Cancer Res ; 78(20): 5741-5753, 2018 10 15.
Artigo em Inglês | MEDLINE | ID: mdl-30072395

RESUMO

The expression of miRNAs in cancer has been widely studied and has allowed the definition of oncomirs and oncosuppressors. We note that it is often underestimated that many mRNAs are expressed, but translationally silent. In spite of this, systematic identification of miRNAs in equilibrium with their target mRNAs on polysomes has not been widely exploited. To identify biologically active oncomirs, we performed a screen for miRNAs acting on the polysomes of malignant mesothelioma (MPM) cells. Only a small percentage of expressed miRNAs physically associated with polysomes. On polysomes, we identified miRNAs already characterized in MPM, as well as novel ones like miR-24-3p, which acted as a promigratory miRNA in all cancer cells tested. miR-24-3p positively regulated Rho-GTP activity, and inhibition of miR-24-3p reduced growth in MPM cells. Analysis of miR-24-3p common targets, in two mesothelioma cell lines, identified a common subset of downregulated genes. These same genes were downregulated during the progression of multiple cancer types. Among the specific targets of miR-24-3p was cingulin, a tight junction protein that inhibits Rho-GTP activity. Overexpression of miR-24-3p only partially abrogated cingulin mRNA, but completely abrogated cingulin protein, confirming its action via translational repression. We suggest that miR-24-3p is an oncomir and speculate that identification of polysome-associated miRNAs efficiently sorts out biologically active miRNAs from inactive ones.Significance: Subcellular localization of miRNAs may predict their role in cancer and identify novel oncogenic miRNAs involved in cancer progression.Graphical Abstract: http://cancerres.aacrjournals.org/content/canres/78/20/5741/F1.large.jpg Cancer Res; 78(20); 5741-53. ©2018 AACR.


Assuntos
Neoplasias Pulmonares/metabolismo , Mesotelioma/metabolismo , MicroRNAs/genética , Neoplasias/genética , Polirribossomos/metabolismo , Animais , Linhagem Celular Tumoral , Movimento Celular , Progressão da Doença , Perfilação da Expressão Gênica , Humanos , Neoplasias Pulmonares/genética , Proteínas de Membrana/metabolismo , Mesotelioma/genética , Mesotelioma Maligno , Camundongos , Camundongos Endogâmicos NOD , Camundongos SCID , Proteínas dos Microfilamentos/metabolismo , Metástase Neoplásica , Ribossomos/metabolismo , Análise de Sequência de RNA , Cicatrização
17.
Mol Cell ; 70(4): 628-638.e5, 2018 05 17.
Artigo em Inglês | MEDLINE | ID: mdl-29775579

RESUMO

Cell survival to replication stress depends on the activation of the Mec1ATR-Rad53 checkpoint response that protects the integrity of stalled forks and controls the origin firing program. Here we found that Mad2, a member of the spindle assembly checkpoint (SAC), contributes to efficient origin firing and to cell survival in response to replication stress. We show that Rad53 and Mad2 promote S-phase cyclin expression through different mechanisms: while Rad53 influences Clb5,6 degradation, Mad2 promotes their protein synthesis. We found that Mad2 co-sediments with polysomes and modulates the association of the translation inhibitor Caf204E-BP with the translation machinery and the initiation factor eIF4E. This Mad2-dependent translational regulatory process does not depend on other SAC proteins. Altogether our observations indicate that Mad2 has an additional function outside of mitosis to control DNA synthesis and collaborates with the Mec1-Rad53 regulatory axis to allow cell survival in response to replication stress.


Assuntos
Ciclinas/genética , Replicação do DNA , Proteínas Mad2/metabolismo , Mitose , Biossíntese de Proteínas , Fase S , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/metabolismo , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Quinase do Ponto de Checagem 2/genética , Quinase do Ponto de Checagem 2/metabolismo , Ciclina B/genética , Ciclina B/metabolismo , Ciclinas/metabolismo , Proteínas Mad2/genética , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Origem de Replicação , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/crescimento & desenvolvimento , Proteínas de Saccharomyces cerevisiae/genética , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo
18.
Curr Opin Genet Dev ; 48: 75-81, 2018 02.
Artigo em Inglês | MEDLINE | ID: mdl-29153483

RESUMO

Albeit cancer patients' heterogeneity, all tumor cells have alterations of both metabolism and translation. The simplest explanation for this common feature is that several oncogenes coordinate a translational and metabolic reprogramming that is necessary for tumor cells to thrive. Overall, at least three oncogenic pathways, namely c-Myc, RAS and PI3K-mTOR, are known to affect both translation and metabolism by stimulating glycolysis and protein synthesis. The crosstalk between metabolite production and the translational machinery is, instead, less understood. What is known is that, on one side, translation initiation factors, such as eIF4E and eIF6, drive tumor growth and regulate metabolism through selective translation of nucleotide biosynthesis, glycolysis and fatty acid synthesis rate-limiting mRNAs, and on the other, that nutrient levels regulate the translational machinery by inducing full activity of translation factors. Therefore, translation and metabolism offer several therapeutic targets to be fully exploited in future studies.


Assuntos
Neoplasias/metabolismo , Biossíntese de Proteínas , Animais , Carcinogênese , Humanos , Proteínas Oncogênicas/genética , Proteínas Oncogênicas/metabolismo , Fatores de Iniciação de Peptídeos/metabolismo
19.
Cell Rep ; 21(6): 1507-1520, 2017 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-29117557

RESUMO

Regular endurance training improves muscle oxidative capacity and reduces the risk of age-related disorders. Understanding the molecular networks underlying this phenomenon is crucial. Here, by exploiting the power of computational modeling, we show that endurance training induces profound changes in gene regulatory networks linking signaling and selective control of translation to energy metabolism and tissue remodeling. We discovered that knockdown of the mTOR-independent factor Eif6, which we predicted to be a key regulator of this process, affects mitochondrial respiration efficiency, ROS production, and exercise performance. Our work demonstrates the validity of a data-driven approach to understanding muscle homeostasis.


Assuntos
Fatores de Iniciação em Eucariotos/metabolismo , Exercício Físico , Músculo Esquelético/metabolismo , Acetilação , Animais , Calorimetria , Cromatografia Líquida de Alta Pressão , Regulação para Baixo , Metabolismo Energético/fisiologia , Fatores de Iniciação em Eucariotos/deficiência , Fatores de Iniciação em Eucariotos/genética , Redes Reguladoras de Genes , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Mitocôndrias/metabolismo , Análise de Sequência com Séries de Oligonucleotídeos , Oxigênio/metabolismo , Condicionamento Físico Animal , Proteoma/análise , Espécies Reativas de Oxigênio/metabolismo , Ribossomos/metabolismo , Espectrometria de Massas em Tandem , Transcrição Genética , Regulação para Cima
20.
Data Brief ; 14: 653-658, 2017 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-28924581

RESUMO

The data described in this article are related to "High levels of eukaryotic Initiation Factor 6 (eIF6) are required for immune system homeostasis and for steering the glycolytic flux of TCR-stimulated CD4+ T cells in both mice and humans" (Manfrini et al., in press) [1]. eIF6 is a translation initiation factor required for ribosomal biogenesis (Sanvito et al., 1999) [2] and for proper translational initiation (Gallo and Manfrini, 2015; Miluzio et al., 2016) [3], [4] whose protein abundance requires tight regulation. Here we analyze by flow cytometry the effects of eIF6 depletion on proportions of specific innate and adaptive immune system subpopulations and on thymocyte maturation in mice.

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