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1.
Cell ; 174(2): 391-405.e19, 2018 07 12.
Artigo em Inglês | MEDLINE | ID: mdl-29937225

RESUMO

Transposable elements represent nearly half of mammalian genomes and are generally described as parasites, or "junk DNA." The LINE1 retrotransposon is the most abundant class and is thought to be deleterious for cells, yet it is paradoxically highly expressed during early development. Here, we report that LINE1 plays essential roles in mouse embryonic stem cells (ESCs) and pre-implantation embryos. In ESCs, LINE1 acts as a nuclear RNA scaffold that recruits Nucleolin and Kap1/Trim28 to repress Dux, the master activator of a transcriptional program specific to the 2-cell embryo. In parallel, LINE1 RNA mediates binding of Nucleolin and Kap1 to rDNA, promoting rRNA synthesis and ESC self-renewal. In embryos, LINE1 RNA is required for Dux silencing, synthesis of rRNA, and exit from the 2-cell stage. The results reveal an essential partnership between LINE1 RNA, Nucleolin, Kap1, and peri-nucleolar chromatin in the regulation of transcription, developmental potency, and ESC self-renewal.


Assuntos
Fosfoproteínas/metabolismo , Proteínas de Ligação a RNA/metabolismo , Animais , Diferenciação Celular , Linhagem Celular , Autorrenovação Celular , Imunoprecipitação da Cromatina , Retrovirus Endógenos/genética , Feminino , Proteínas de Homeodomínio/antagonistas & inibidores , Proteínas de Homeodomínio/genética , Proteínas de Homeodomínio/metabolismo , Hibridização in Situ Fluorescente , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Células-Tronco Embrionárias Murinas/citologia , Células-Tronco Embrionárias Murinas/metabolismo , Oligorribonucleotídeos Antissenso/metabolismo , Fosfoproteínas/antagonistas & inibidores , Fosfoproteínas/genética , Interferência de RNA , RNA Ribossômico/metabolismo , Proteínas de Ligação a RNA/antagonistas & inibidores , Proteínas de Ligação a RNA/genética , Proteína 28 com Motivo Tripartido/antagonistas & inibidores , Proteína 28 com Motivo Tripartido/genética , Proteína 28 com Motivo Tripartido/metabolismo , Regulação para Cima , Nucleolina
2.
Mol Cell ; 84(9): 1811-1815.e3, 2024 May 02.
Artigo em Inglês | MEDLINE | ID: mdl-38701742

RESUMO

Post-translational modifications of proteins (PTMs) introduce an extra layer of complexity to cellular regulation. Although phosphorylation of serine, threonine, and tyrosine residues is well-known as PTMs, lysine is, in fact, the most heavily modified amino acid, with over 30 types of PTMs on lysine having been characterized. One of the most recently discovered PTMs on lysine residues is polyphosphorylation, which sees linear chains of inorganic polyphosphates (polyP) attached to lysine residues. The labile nature of phosphoramidate bonds raises the question of whether this modification is covalent in nature. Here, we used buffers with very high ionic strength, which would disrupt any non-covalent interactions, and confirmed that lysine polyphosphorylation occurs covalently on proteins containing PASK domains (polyacidic, serine-, and lysine-rich), such as the budding yeast protein nuclear signal recognition 1 (Nsr1) and the mammalian protein nucleolin. This Matters Arising Response paper addresses the Neville et al. (2024) Matters Arising paper, published concurrently in Molecular Cell.


Assuntos
Lisina , Fosfoproteínas , Processamento de Proteína Pós-Traducional , Proteínas de Ligação a RNA , Fosforilação , Lisina/metabolismo , Fosfoproteínas/metabolismo , Fosfoproteínas/química , Fosfoproteínas/genética , Humanos , Proteínas de Ligação a RNA/metabolismo , Proteínas de Ligação a RNA/genética , Proteínas de Ligação a RNA/química , Nucleolina , Proteínas de Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/química , Animais , Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/genética , Polifosfatos/metabolismo , Polifosfatos/química , Concentração Osmolar
3.
Mol Cell ; 82(14): 2604-2617.e8, 2022 07 21.
Artigo em Inglês | MEDLINE | ID: mdl-35654044

RESUMO

Stress-induced cleavage of transfer RNAs (tRNAs) into tRNA-derived fragments (tRFs) occurs across organisms from yeast to humans; yet, its mechanistic underpinnings and pathological consequences remain poorly defined. Small RNA profiling revealed increased abundance of a cysteine tRNA fragment (5'-tRFCys) during breast cancer metastatic progression. 5'-tRFCys was required for efficient breast cancer metastatic lung colonization and cancer cell survival. We identified Nucleolin as the direct binding partner of 5'-tRFCys. 5'-tRFCys promoted the oligomerization of Nucleolin and its bound metabolic transcripts Mthfd1l and Pafah1b1 into a higher-order transcript stabilizing ribonucleoprotein complex, which protected these transcripts from exonucleolytic degradation. Consistent with this, Mthfd1l and Pafah1b1 mediated pro-metastatic and metabolic effects downstream of 5'-tRFCys-impacting folate, one-carbon, and phosphatidylcholine metabolism. Our findings reveal that a tRF can promote oligomerization of an RNA-binding protein into a transcript stabilizing ribonucleoprotein complex, thereby driving specific metabolic pathways underlying cancer progression.


Assuntos
Neoplasias da Mama , RNA de Transferência , Neoplasias da Mama/genética , Feminino , Humanos , Fosfoproteínas , RNA Mensageiro/genética , RNA de Transferência/metabolismo , Proteínas de Ligação a RNA/genética , Proteínas de Ligação a RNA/metabolismo , Ribonucleoproteínas/genética , Nucleolina
4.
Mol Cell ; 82(14): 2536-2538, 2022 07 21.
Artigo em Inglês | MEDLINE | ID: mdl-35868253

RESUMO

In this issue of Molecular Cell, Liu et al. (2022) report that 5'-tRFCys, a stress-induced transfer RNA-derived RNA fragment (tRF) derived from the 5' halves of cysteine tRNAs, regulates post-transcriptional gene expression, enabling the survival and lung metastasis formation of breast cancers.


Assuntos
Neoplasias da Mama , Proteínas de Ligação a RNA , Neoplasias da Mama/genética , Feminino , Humanos , Fosfoproteínas/genética , Fosfoproteínas/metabolismo , RNA de Transferência/genética , RNA de Transferência/metabolismo , Proteínas de Ligação a RNA/genética , Proteínas de Ligação a RNA/metabolismo , Nucleolina
5.
EMBO J ; 42(11): e110902, 2023 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-37039106

RESUMO

Oncogenic RAS signaling reprograms gene expression through both transcriptional and post-transcriptional mechanisms. While transcriptional regulation downstream of RAS is relatively well characterized, how RAS post-transcriptionally modulates gene expression to promote malignancy remains largely unclear. Using quantitative RNA interactome capture analysis, we here reveal that oncogenic RAS signaling reshapes the RNA-bound proteomic landscape of pancreatic cancer cells, with a network of nuclear proteins centered around nucleolin displaying enhanced RNA-binding activity. We show that nucleolin is phosphorylated downstream of RAS, which increases its binding to pre-ribosomal RNA (rRNA), boosts rRNA production, and promotes ribosome biogenesis. This nucleolin-dependent enhancement of ribosome biogenesis is crucial for RAS-induced pancreatic cancer cell proliferation and can be targeted therapeutically to inhibit tumor growth. Our results reveal that oncogenic RAS signaling drives ribosome biogenesis by regulating the RNA-binding activity of nucleolin and highlight a crucial role for this mechanism in RAS-mediated tumorigenesis.


Assuntos
Genes ras , Neoplasias Pancreáticas , Humanos , Sistema de Sinalização das MAP Quinases , Proteômica , Fosfoproteínas/metabolismo , RNA Ribossômico/metabolismo , RNA/metabolismo , Transformação Celular Neoplásica/genética , Ribossomos/genética , Ribossomos/metabolismo , Neoplasias Pancreáticas/genética , Neoplasias Pancreáticas/metabolismo , Nucleolina
6.
Nature ; 583(7817): 615-619, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32494007

RESUMO

Pneumonia resulting from infection is one of the leading causes of death worldwide. Pulmonary infection by the respiratory syncytial virus (RSV) is a large burden on human health, for which there are few therapeutic options1. RSV targets ciliated epithelial cells in the airways, but how viruses such as RSV interact with receptors on these cells is not understood. Nucleolin is an entry coreceptor for RSV2 and also mediates the cellular entry of influenza, the parainfluenza virus, some enteroviruses and the bacterium that causes tularaemia3,4. Here we show a mechanism of RSV entry into cells in which outside-in signalling, involving binding of the prefusion RSV-F glycoprotein with the insulin-like growth factor-1 receptor, triggers the activation of protein kinase C zeta (PKCζ). This cellular signalling cascade recruits nucleolin from the nuclei of cells to the plasma membrane, where it also binds to RSV-F on virions. We find that inhibiting PKCζ activation prevents the trafficking of nucleolin to RSV particles on airway organoid cultures, and reduces viral replication and pathology in RSV-infected mice. These findings reveal a mechanism of virus entry in which receptor engagement and signal transduction bring the coreceptor to viral particles at the cell surface, and could form the basis of new therapeutics to treat RSV infection.


Assuntos
Receptor IGF Tipo 1/metabolismo , Receptores Virais/metabolismo , Vírus Sinciciais Respiratórios/metabolismo , Internalização do Vírus , Linhagem Celular , Núcleo Celular/metabolismo , Ativação Enzimática , Humanos , Fusão de Membrana/efeitos dos fármacos , Fosfoproteínas/metabolismo , Ligação Proteica , Proteína Quinase C/antagonistas & inibidores , Proteína Quinase C/metabolismo , Proteínas de Ligação a RNA/metabolismo , Receptor IGF Tipo 1/antagonistas & inibidores , Vírus Sinciciais Respiratórios/efeitos dos fármacos , Vírus Sinciciais Respiratórios/patogenicidade , Vírus Sinciciais Respiratórios/fisiologia , Carga Viral/efeitos dos fármacos , Internalização do Vírus/efeitos dos fármacos , Nucleolina
7.
Proc Natl Acad Sci U S A ; 120(49): e2306390120, 2023 Dec 05.
Artigo em Inglês | MEDLINE | ID: mdl-38015841

RESUMO

Hepatitis B virus (HBV) remains a major public health threat with nearly 300 million people chronically infected worldwide who are at a high risk of developing hepatocellular carcinoma. Current therapies are effective in suppressing HBV replication but rarely lead to cure. Current therapies do not affect the HBV covalently closed circular DNA (cccDNA), which serves as the template for viral transcription and replication and is highly stable in infected cells to ensure viral persistence. In this study, we aim to identify and elucidate the functional role of cccDNA-associated host factors using affinity purification and protein mass spectrometry in HBV-infected cells. Nucleolin was identified as a key cccDNA-binding protein and shown to play an important role in HBV cccDNA transcription, likely via epigenetic regulation. Targeting nucleolin to silence cccDNA transcription in infected hepatocytes may be a promising therapeutic strategy for a functional cure of HBV.


Assuntos
Hepatite B , Neoplasias Hepáticas , Humanos , Vírus da Hepatite B/fisiologia , Epigênese Genética , Replicação Viral/genética , DNA Viral/metabolismo , DNA Circular/genética , DNA Circular/metabolismo , Neoplasias Hepáticas/genética , Hepatite B/genética , Hepatite B/metabolismo , Nucleolina
8.
Hum Mol Genet ; 32(23): 3263-3275, 2023 Nov 17.
Artigo em Inglês | MEDLINE | ID: mdl-37658769

RESUMO

The COPI coatomer subunit α-COP has been shown to co-precipitate mRNA in multiple settings, but it was unclear whether the interaction with mRNA was direct or mediated by interaction with an adapter protein. The COPI complex often interacts with proteins via C-terminal dilysine domains. A search for candidate RNA binding proteins with C-terminal dilysine motifs yielded Nucleolin, which terminates in a KKxKxx sequence. This protein was an especially intriguing candidate as it has been identified as an interacting partner for Survival Motor Neuron protein (SMN). Loss of SMN causes the neurodegenerative disease Spinal Muscular Atrophy. We have previously shown that SMN and α-COP interact and co-migrate in axons, and that overexpression of α-COP reduced phenotypic severity in cell culture and animal models of SMA. We show here that in an mRNA independent manner, endogenous Nucleolin co-precipitates endogenous α-COP and ε-COP but not ß-COP which may reflect an interaction with the so-called B-subcomplex rather a complete COPI heptamer. The ability of Nucleolin to bind to α-COP requires the presence of the C-terminal KKxKxx domain of Nucleolin. Furthermore, we have generated a point mutant in the WD40 domain of α-COP which eliminates its ability to co-precipitate Nucleolin but does not interfere with precipitation of partners mediated by non-KKxKxx motifs such as the kainate receptor subunit 2. We propose that via interaction between the C-terminal dilysine motif of Nucleolin and the WD40 domain of α-COP, Nucleolin acts an adaptor to allow α-COP to interact with a population of mRNA.


Assuntos
Atrofia Muscular Espinal , Doenças Neurodegenerativas , Animais , Proteína Coatomer/genética , Ligação Proteica , Fosfoproteínas/genética , Fosfoproteínas/metabolismo , Atrofia Muscular Espinal/genética , Proteínas de Ligação a RNA/genética , Proteínas de Ligação a RNA/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Nucleolina
9.
EMBO J ; 40(20): e107158, 2021 10 18.
Artigo em Inglês | MEDLINE | ID: mdl-34515347

RESUMO

Nucleolin is a multifunctional RNA Binding Protein (RBP) with diverse subcellular localizations, including the nucleolus in all eukaryotic cells, the plasma membrane in tumor cells, and the axon in neurons. Here we show that the glycine arginine rich (GAR) domain of nucleolin drives subcellular localization via protein-protein interactions with a kinesin light chain. In addition, GAR sequences mediate plasma membrane interactions of nucleolin. Both these modalities are in addition to the already reported involvement of the GAR domain in liquid-liquid phase separation in the nucleolus. Nucleolin transport to axons requires the GAR domain, and heterozygous GAR deletion mice reveal reduced axonal localization of nucleolin cargo mRNAs and enhanced sensory neuron growth. Thus, the GAR domain governs axonal transport of a growth controlling RNA-RBP complex in neurons, and is a versatile localization determinant for different subcellular compartments. Localization determination by GAR domains may explain why GAR mutants in diverse RBPs are associated with neurodegenerative disease.


Assuntos
Nucléolo Celular/metabolismo , Gânglios Espinais/metabolismo , Cinesinas/metabolismo , Neurônios/metabolismo , Fosfoproteínas/química , Proteínas de Ligação a RNA/química , Nervo Isquiático/metabolismo , Sequência de Aminoácidos , Animais , Transporte Axonal/genética , Linhagem Celular Tumoral , Nucléolo Celular/ultraestrutura , Gânglios Espinais/citologia , Expressão Gênica , Células HEK293 , Células HeLa , Humanos , Cinesinas/genética , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Mutação , Neurônios/citologia , Fosfoproteínas/genética , Fosfoproteínas/metabolismo , Cultura Primária de Células , Domínios Proteicos , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Proteínas de Ligação a RNA/genética , Proteínas de Ligação a RNA/metabolismo , Nervo Isquiático/citologia , Nucleolina
10.
Development ; 149(12)2022 06 15.
Artigo em Inglês | MEDLINE | ID: mdl-35762670

RESUMO

Ribosomal RNA (rRNA) transcription and ribosome biogenesis are global processes required for growth and proliferation of all cells, yet perturbation of these processes in vertebrates leads to tissue-specific defects termed ribosomopathies. Mutations in rRNA transcription and processing proteins often lead to craniofacial anomalies; however, the cellular and molecular reasons for these defects are poorly understood. Therefore, we examined the function of the most abundant nucleolar phosphoprotein, Nucleolin (Ncl), in vertebrate development. ncl mutant (ncl-/-) zebrafish present with craniofacial anomalies such as mandibulofacial hypoplasia. We observed that ncl-/- mutants exhibited decreased rRNA synthesis and p53-dependent apoptosis, consistent with a role in ribosome biogenesis. However, we found that Nucleolin also performs functions not associated with ribosome biogenesis. We discovered that the half-life of fgf8a mRNA was reduced in ncl-/- mutants, which perturbed Fgf signaling, resulting in misregulated Sox9a-mediated chondrogenesis and Runx2-mediated osteogenesis. Consistent with this model, exogenous FGF8 treatment significantly rescued the cranioskeletal phenotype in ncl-/- zebrafish, suggesting that Nucleolin regulates osteochondroprogenitor differentiation. Our work has therefore uncovered tissue-specific functions for Nucleolin in rRNA transcription and post-transcriptional regulation of growth factor signaling during embryonic craniofacial development.


Assuntos
Anormalidades Craniofaciais , Peixe-Zebra , Animais , Fatores de Crescimento de Fibroblastos/metabolismo , Fosfoproteínas/metabolismo , RNA Ribossômico/genética , Proteínas de Ligação a RNA/metabolismo , Nucleolina
11.
RNA ; 29(5): 630-643, 2023 05.
Artigo em Inglês | MEDLINE | ID: mdl-36653114

RESUMO

p53 protein is a key regulator of cellular homeostasis by coordinating the framework of antiproliferative pathways as a response to various stress factors. Although the main mechanism of stress-dependent induction of p53 protein relies on post-translational modifications influencing its stability and activity, a growing amount of evidence suggests that complex regulation of p53 expression occurs also at the mRNA level. This study explores structural determinants of long-range RNA-RNA interactions in p53 mRNA, crucial for stress-dependent regulation of p53 protein translation. We demonstrate that the 8-nt bulge motif plays a key structural role in base-pairing of complementary sequences from the 5' and 3' untranslated regions of p53 mRNA. We also show that one of the p53 translation regulators, nucleolin, displays an RNA chaperone activity and facilitates the association of sequences involved in the formation of long-range interactions in p53 mRNA. Nucleolin promotes base-pairing of complementary sequences through the bulge motif, because mutations of this region reduce or inhibit pairing while compensatory mutations restore this interaction. Mutational analysis of nucleolin reveals that all four RNA recognition motifs are indispensable for optimal RNA chaperone activity of nucleolin. These observations help to decipher the unique mechanism of p53 protein translation regulation pointing to bulge motif and nucleolin as the critical factors during intramolecular RNA-RNA recognition in p53 mRNA.


Assuntos
Fosfoproteínas , Proteína Supressora de Tumor p53 , Proteína Supressora de Tumor p53/genética , RNA Mensageiro/metabolismo , Regiões 3' não Traduzidas , Regiões 5' não Traduzidas/genética , Nucleolina
12.
J Virol ; 98(2): e0167723, 2024 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-38240590

RESUMO

Rotavirus infection is a leading cause of gastroenteritis in children worldwide; the genome of this virus is composed of 11 segments of dsRNA packed in a triple-layered protein capsid. Here, we investigated the role of nucleolin, a protein with diverse RNA-binding domains, in rotavirus infection. Knocking down the expression of nucleolin in MA104 cells by RNA interference resulted in a remarkable 6.3-fold increase in the production of infectious rhesus rotavirus (RRV) progeny, accompanied by an elevated synthesis of viral mRNA and genome copies. Further analysis unveiled an interaction between rotavirus segment 10 (S10) and nucleolin, potentially mediated by G-quadruplex domains on the viral genome. To determine whether the nucleolin-RNA interaction regulates RRV replication, MA104 cells were transfected with AGRO100, a compound that forms G4 structures and selectively inhibits nucleolin-RNA interactions by blocking the RNA-binding domains. Under these conditions, viral production increased by 1.5-fold, indicating the inhibitory role of nucleolin on the yield of infectious viral particles. Furthermore, G4 sequences were identified in all 11 RRV dsRNA segments, and transfection of oligonucleotides representing G4 sequences in RRV S10 induced a significant increase in viral production. These findings show that rotavirus replication is negatively regulated by nucleolin through the direct interaction with the viral RNAs by sequences forming G4 structures.IMPORTANCEViruses rely on cellular proteins to carry out their replicative cycle. In the case of rotavirus, the involvement of cellular RNA-binding proteins during the replicative cycle is a poorly studied field. In this work, we demonstrate for the first time the interaction between nucleolin and viral RNA of rotavirus RRV. Nucleolin is a cellular protein that has a role in the metabolism of ribosomal rRNA and ribosome biogenesis, which seems to have regulatory effects on the quantity of viral particles and viral RNA copies of rotavirus RRV. Our study adds a new component to the current model of rotavirus replication, where cellular proteins can have a negative regulation on rotavirus replication.


Assuntos
Nucleolina , RNA Viral , Infecções por Rotavirus , Rotavirus , Humanos , Nucleolina/metabolismo , RNA Viral/genética , Rotavirus/fisiologia , Infecções por Rotavirus/virologia , Replicação Viral
13.
J Virol ; 98(8): e0085824, 2024 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-39078257

RESUMO

Japanese encephalitis virus (JEV) is an arthropod-borne, plus-strand flavivirus causing viral encephalitis in humans with a high case fatality rate. The JEV non-structural protein 5 (NS5) with the RNA-dependent RNA polymerase activity interacts with the viral and host proteins to constitute the replication complex. We have identified the multifunctional protein Nucleolin (NCL) as one of the several NS5-interacting host proteins. We demonstrate the interaction and colocalization of JEV NS5 with NCL in the virus-infected HeLa cells. The siRNA-mediated knockdown of NCL indicated that it was required for efficient viral replication. Importantly, JEV grew to higher titers in cells over-expressing exogenous NCL, demonstrating its pro-viral role. We demonstrated that NS5 interacted with the RRM and GAR domains of NCL. We show that the NCL-binding aptamer AS1411 containing the G-quadruplex (GQ) structure and the GQ ligand BRACO-19 caused significant inhibition of JEV replication. The antiviral effect of AS1411 and BRACO-19 could be overcome in HeLa cells by the overexpression of exogenous NCL. We demonstrated that the synthetic RNAs derived from the 3'-NCR of JEV genomic RNA containing the GQ sequence could bind NCL in vitro. The replication complex binding to the 3'-NCR is required for the viral RNA synthesis. It is likely that NCL present in the replication complex destabilizes the GQ structures in the genomic RNA, thus facilitating the movement of the replication complex resulting in efficient virus replication.IMPORTANCEJapanese encephalitis virus (JEV) is endemic in most parts of South-East Asia and the Western Pacific region, causing epidemics of encephalitis with a high case fatality rate. While a tissue culture-derived JEV vaccine is available, no antiviral therapy exists. The JEV NS5 protein has RNA-dependent RNA polymerase activity. Together with several host and viral proteins, it constitutes the replication complex necessary for virus replication. Understanding the interaction of NS5 with the host proteins could help design novel antivirals. We identified Nucleolin (NCL) as a crucial host protein interactor of JEV NS5 having a pro-viral role in virus replication. The NS5-interacting NCL binds to the G-quadruplex (GQ) structure sequence in the 3'-NCR of JEV RNA. This may smoothen the movement of the replication complex along the genomic RNA, thereby facilitating the virus replication. This study is the first report on how NCL, a host protein, helps in JEV replication through GQ-binding.


Assuntos
Vírus da Encefalite Japonesa (Espécie) , Nucleolina , Fosfoproteínas , Proteínas de Ligação a RNA , Proteínas não Estruturais Virais , Replicação Viral , Humanos , Vírus da Encefalite Japonesa (Espécie)/fisiologia , Vírus da Encefalite Japonesa (Espécie)/metabolismo , Proteínas de Ligação a RNA/metabolismo , Proteínas de Ligação a RNA/genética , Proteínas não Estruturais Virais/metabolismo , Proteínas não Estruturais Virais/genética , Fosfoproteínas/metabolismo , Fosfoproteínas/genética , Células HeLa , Ligação Proteica , Encefalite Japonesa/virologia , Encefalite Japonesa/metabolismo , Interações Hospedeiro-Patógeno , Quadruplex G , Animais
14.
Nucleic Acids Res ; 51(17): 9415-9431, 2023 09 22.
Artigo em Inglês | MEDLINE | ID: mdl-37558241

RESUMO

Nuclear-retained long non-coding RNAs (lncRNAs) including MALAT1 have emerged as critical regulators of many molecular processes including transcription, alternative splicing and chromatin organization. Here, we report the presence of three conserved and thermodynamically stable RNA G-quadruplexes (rG4s) located in the 3' region of MALAT1. Using rG4 domain-specific RNA pull-down followed by mass spectrometry and RNA immunoprecipitation, we demonstrated that the MALAT1 rG4 structures are specifically bound by two nucleolar proteins, Nucleolin (NCL) and Nucleophosmin (NPM). Using imaging, we found that the MALAT1 rG4s facilitate the localization of both NCL and NPM to nuclear speckles, and specific G-to-A mutations that disrupt the rG4 structures compromised the localization of both NCL and NPM in speckles. In vitro biophysical studies established that a truncated version of NCL (ΔNCL) binds tightly to all three rG4s. Overall, our study revealed new rG4s within MALAT1, established that they are specifically recognized by NCL and NPM, and showed that disrupting the rG4s abolished localization of these proteins to nuclear speckles.


Assuntos
Quadruplex G , RNA Longo não Codificante , Nucleofosmina , Fosfoproteínas/genética , Fosfoproteínas/metabolismo , RNA Longo não Codificante/genética , Humanos , Nucleolina
15.
Drug Resist Updat ; 76: 101122, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-39079407

RESUMO

O6-methylguanine DNA methyltransferase (MGMT) is a crucial determinant of temozolomide (TMZ) sensitivity in patients with glioblastoma (GBM). The therapeutic potential of small interfering RNA (siRNA) targeting MGMT to enhance TMZ sensitivity has been hampered by serum nuclease degradation, off-target effects, poor accumulation at tumor sites, and low circulation in blood stream. In this study, we developed a framework nucleic acid-based nanoparticles (FNN), which is constructed from a six-helix DNA bundle, to encapsulate and protect siMGMT for improving TMZ sensitivity in GBM treatment. For better blood-brain barrier (BBB) penetration and GBM targeting, we conjugated Angiopep-2 (ANG) targeting modules to each end of the FNN. Nucleolin (NCL)-responsive locks were engineered along the sides of the six-helix DNA bundle, which safeguard siMGMT before tumor entry. Upon interaction with tumor-overexpressed NCL, these locks unlock, exposing siMGMT, this allows for effective suppression of MGMT, resulting in a significant improvement of TMZ therapeutic efficacy in GBM. This innovative strategy has the potential to transform the current treatment landscape for GBM.


Assuntos
Antineoplásicos Alquilantes , Barreira Hematoencefálica , Neoplasias Encefálicas , Glioblastoma , Nanopartículas , Temozolomida , Glioblastoma/tratamento farmacológico , Glioblastoma/patologia , Temozolomida/farmacologia , Temozolomida/administração & dosagem , Temozolomida/uso terapêutico , Humanos , Neoplasias Encefálicas/tratamento farmacológico , Neoplasias Encefálicas/patologia , Neoplasias Encefálicas/genética , Antineoplásicos Alquilantes/farmacologia , Antineoplásicos Alquilantes/uso terapêutico , Nanopartículas/química , Animais , Barreira Hematoencefálica/metabolismo , Barreira Hematoencefálica/efeitos dos fármacos , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Linhagem Celular Tumoral , Proteínas de Ligação a RNA/metabolismo , Enzimas Reparadoras do DNA/metabolismo , Enzimas Reparadoras do DNA/genética , Metilases de Modificação do DNA/metabolismo , Nucleolina , Fosfoproteínas/metabolismo , Proteínas Supressoras de Tumor/metabolismo , Proteínas Supressoras de Tumor/genética , RNA Interferente Pequeno/administração & dosagem , Ácidos Nucleicos , Peptídeos
16.
J Cell Mol Med ; 28(18): e70077, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-39304978

RESUMO

In addressing the challenges of lung cancer, attention has increasingly turned to molecular diagnostics and targeted therapies, with nucleolin (NCL) assuming a pivotal role, especially in non-small cell lung cancer. The aberrant activity and cellular distribution of NCL act as crucial biomarkers for early detection and treatment monitoring, showing a strong correlation with disease progression and patient prognosis. Elevated NCL levels signal advanced disease and poorer outcomes, underscoring its significance in evaluating disease severity and therapeutic response. Strategies targeting the molecular interactions of NCL have spurred innovative approaches to inhibit tumour growth, overcome drug resistance and improve treatment efficacy. These advancements are paving the way for personalized therapies tailored to the unique molecular profiles of patients' tumours. Consequently, NCL stands at the forefront of lung cancer management, symbolizing the move towards more precise and individualized oncology care, and marking substantial progress in therapeutic development.


Assuntos
Biomarcadores Tumorais , Neoplasias Pulmonares , Nucleolina , Fosfoproteínas , Proteínas de Ligação a RNA , Humanos , Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/diagnóstico , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/terapia , Neoplasias Pulmonares/patologia , Neoplasias Pulmonares/tratamento farmacológico , Biomarcadores Tumorais/metabolismo , Biomarcadores Tumorais/genética , Fosfoproteínas/metabolismo , Proteínas de Ligação a RNA/metabolismo , Proteínas de Ligação a RNA/genética , Carcinoma Pulmonar de Células não Pequenas/metabolismo , Carcinoma Pulmonar de Células não Pequenas/genética , Carcinoma Pulmonar de Células não Pequenas/diagnóstico , Carcinoma Pulmonar de Células não Pequenas/terapia , Carcinoma Pulmonar de Células não Pequenas/patologia , Prognóstico , Animais , Terapia de Alvo Molecular
17.
Chromosoma ; 132(4): 305-315, 2023 11.
Artigo em Inglês | MEDLINE | ID: mdl-37615728

RESUMO

Nucleolin is a multifunctional RNA-binding protein that resides predominantly not only in the nucleolus, but also in multiple other subcellular pools in the cytoplasm in mammalian cells, and is best known for its roles in ribosome biogenesis, RNA stability, and translation. During early mitosis, nucleolin is required for equatorial mitotic chromosome alignment prior to metaphase. Using high resolution fluorescence imaging, we reveal that nucleolin is required for multiple centrosome-associated functions at the G2-prophase boundary. Nucleolin depletion led to dissociation of the centrosomes from the G2 nuclear envelope, a delay in the onset of nuclear envelope breakdown, reduced inter-centrosome separation, and longer metaphase spindles. Our results reveal novel roles for nucleolin in early mammalian mitosis, establishing multiple important functions for nucleolin during mammalian cell division.


Assuntos
Nucleolina , Fuso Acromático , Animais , Fuso Acromático/metabolismo , Centrossomo/metabolismo , Mitose , Vertebrados , Mamíferos
18.
J Hepatol ; 81(4): 651-666, 2024 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-38679071

RESUMO

BACKGROUND & AIMS: Intrahepatic cholangiocarcinoma (iCCA) is a fatal malignancy of the biliary system. The lack of a detailed understanding of oncogenic signaling or global gene expression alterations has impeded clinical iCCA diagnosis and therapy. The role of protein lactylation, a newly unraveled post-translational modification that orchestrates gene expression, remains largely elusive in the pathogenesis of iCCA. METHODS: Proteomics analysis of clinical iCCA specimens and adjacent tissues was performed to screen for proteins aberrantly lactylated in iCCA. Mass spectrometry, macromolecule interaction and cell behavioral studies were employed to identify the specific lactylation sites on the candidate protein(s) and to decipher the downstream mechanisms responsible for iCCA development, which were subsequently validated using a xenograft tumor model and clinical samples. RESULTS: Nucleolin (NCL), the most abundant RNA-binding protein in the nucleolus, was identified as a functional lactylation target that correlates with iCCA occurrence and progression. NCL was lactylated predominantly at lysine 477 by the acyltransferase P300 in response to a hyperactivity of glycolysis, and promoted the proliferation and invasion of iCCA cells. Mechanistically, lactylated NCL bound to the primary transcript of MAP kinase-activating death domain protein (MADD) and led to efficient translation of MADD by circumventing alternative splicing that generates a premature termination codon. NCL lactylation, MADD translation and subsequent ERK activation promoted xenograft tumor growth and were associated with overall survival in patients with iCCA. CONCLUSION: NCL is lactylated to upregulate MADD through an RNA splicing-dependent mechanism, which potentiates iCCA pathogenesis via the MAPK pathway. Our findings reveal a novel link between metabolic reprogramming and canonical tumor-initiating events, and uncover biomarkers that can potentially be used for prognostic evaluation or targeted treatment of iCCA. IMPACT AND IMPLICATIONS: Intrahepatic cholangiocarcinoma (iCCA) is a highly aggressive liver malignancy with largely uncharacterized pathogenetic mechanisms. Herein, we demonstrated that glycolysis promotes P300-catalyzed lactylation of nucleolin, which upregulates MAP kinase-activating death domain protein (MADD) through precise mRNA splicing and activates ERK signaling to drive iCCA development. These findings unravel a novel link between metabolic rewiring and canonical oncogenic pathways, and reveal new biomarkers for prognostic assessment and targeting of clinical iCCA.


Assuntos
Neoplasias dos Ductos Biliares , Colangiocarcinoma , Nucleolina , Fosfoproteínas , Proteínas de Ligação a RNA , Colangiocarcinoma/genética , Colangiocarcinoma/metabolismo , Colangiocarcinoma/patologia , Humanos , Neoplasias dos Ductos Biliares/genética , Neoplasias dos Ductos Biliares/patologia , Neoplasias dos Ductos Biliares/metabolismo , Proteínas de Ligação a RNA/metabolismo , Proteínas de Ligação a RNA/genética , Animais , Fosfoproteínas/metabolismo , Fosfoproteínas/genética , Camundongos , Splicing de RNA , Linhagem Celular Tumoral , Regulação Neoplásica da Expressão Gênica , Processamento de Proteína Pós-Traducional , Proliferação de Células/genética , Proteômica/métodos
19.
Anal Chem ; 96(2): 926-933, 2024 01 16.
Artigo em Inglês | MEDLINE | ID: mdl-38158373

RESUMO

Nucleolin (NCL) is a multifunctional nuclear protein that plays significant roles in regulating physiological activities of the cells. However, it remains a challenge to monitor the dynamic distribution and expression of nucleolin within living cells during cell stress processes directly. Here, we designed "turn-on" fluorescent nanoprobes composed of specific AS1411 aptamer and nucleus-targeting peptide on gold nanoparticles (AuNPs) to effectively capture and track the NCL distribution and expression during pyroptosis triggered by electrical stimulation (ES). The distribution of nucleolin in the cell membrane and nucleus can be easily observed by simply changing the particle size of the nanoprobes. The present strategy exhibits obvious advantages such as simple operation, low cost, time saving, and suitability for living cell imaging. The ES can induce cancer cell pyroptosis controllably and selectively, with less harm to the viability of normal cells. The palpable cell nuclear stress responses of cancerous cells, including nucleus wrinkling and nucleolus fusion after ES at 1.0 V were obviously observed. Compared with normal cells (MCF-10A), NCL is overexpressed within cancerous cells (MCF-7 cells) using the as-designed nanoprobes, and the ES can effectively inhibit NCL expression within cancerous cells. The developed NCL sensing platform and ES-based methods hold great potential for cellular studies of cancer-related diseases.


Assuntos
Aptâmeros de Nucleotídeos , Nanopartículas Metálicas , Humanos , Nucleolina , Proteínas de Ligação a RNA/metabolismo , Ouro/metabolismo , Piroptose , Corantes , Fosfoproteínas/metabolismo
20.
Anal Chem ; 96(33): 13438-13446, 2024 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-39129352

RESUMO

Pyroptosis of programmed cell death has been recognized as a more effective way to inhibit the occurrence and development of tumors than the better-studied apoptosis. However, it is still challenging to quickly and effectively trigger pyroptosis of cancer cells for high-efficacy cancer treatment. Here, we report on the first use of mild constant-potential electrostimulation (cp-ES) to quickly trigger cancer cell pyroptosis with a probability up to ∼91.4% and significantly shortened time (within 1 h), ∼3-6 times faster than typical drug stimulation to induce pyroptosis. We find that the ES-induced cancer cell pyroptosis is through the activated caspase-3 (pathway) cleavage of gasdermin E (GSDME) to form an N-terminal fragment (GSDME-N) and observe nuclear shrinkage and reduction of the number of nucleoli as well as down-/up-regulated expression of two important nucleoproteins of nucleolin and nucleophosmin (NPM1). The study enriches the basic understanding of pyroptosis and provides a new avenue for potential effective treatment of cancer.


Assuntos
Caspase 3 , Nucleofosmina , Piroptose , Humanos , Caspase 3/metabolismo , Nucleolina , Linhagem Celular Tumoral , Núcleo Celular/metabolismo , Proteínas Nucleares/metabolismo , Proteínas de Ligação a Fosfato/metabolismo , Proteínas de Ligação a RNA/metabolismo , Gasderminas
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