RESUMO
Cytoplasmic FUS aggregates are a pathological hallmark in a subset of patients with frontotemporal dementia (FTD) or amyotrophic lateral sclerosis (ALS). A key step that is disrupted in these patients is nuclear import of FUS mediated by the import receptor Transportin/Karyopherin-ß2. In ALS-FUS patients, this is caused by mutations in the nuclear localization signal (NLS) of FUS that weaken Transportin binding. In FTD-FUS patients, Transportin is aggregated, and post-translational arginine methylation, which regulates the FUS-Transportin interaction, is lost. Here, we show that Transportin and arginine methylation have a crucial function beyond nuclear import-namely to suppress RGG/RG-driven phase separation and stress granule association of FUS. ALS-associated FUS-NLS mutations weaken the chaperone activity of Transportin and loss of FUS arginine methylation, as seen in FTD-FUS, promote phase separation, and stress granule partitioning of FUS. Our findings reveal two regulatory mechanisms of liquid-phase homeostasis that are disrupted in FUS-associated neurodegeneration.
Assuntos
Arginina/química , Proteína FUS de Ligação a RNA/química , beta Carioferinas/química , Transporte Ativo do Núcleo Celular , Motivos de Aminoácidos , Citoplasma/metabolismo , Metilação de DNA , DNA Complementar/metabolismo , Densitometria , Degeneração Lobar Frontotemporal/metabolismo , Células HeLa , Homeostase , Humanos , Carioferinas/química , Espectroscopia de Ressonância Magnética , Metilação , Chaperonas Moleculares/química , Mutação , Doenças Neurodegenerativas/metabolismo , Ligação Proteica , Domínios ProteicosRESUMO
Reversible phase separation underpins the role of FUS in ribonucleoprotein granules and other membrane-free organelles and is, in part, driven by the intrinsically disordered low-complexity (LC) domain of FUS. Here, we report that cooperative cation-π interactions between tyrosines in the LC domain and arginines in structured C-terminal domains also contribute to phase separation. These interactions are modulated by post-translational arginine methylation, wherein arginine hypomethylation strongly promotes phase separation and gelation. Indeed, significant hypomethylation, which occurs in FUS-associated frontotemporal lobar degeneration (FTLD), induces FUS condensation into stable intermolecular ß-sheet-rich hydrogels that disrupt RNP granule function and impair new protein synthesis in neuron terminals. We show that transportin acts as a physiological molecular chaperone of FUS in neuron terminals, reducing phase separation and gelation of methylated and hypomethylated FUS and rescuing protein synthesis. These results demonstrate how FUS condensation is physiologically regulated and how perturbations in these mechanisms can lead to disease.
Assuntos
Arginina/química , Chaperonas Moleculares/química , Proteína FUS de Ligação a RNA/química , Esclerose Lateral Amiotrófica/metabolismo , Animais , Cátions , Metilação de DNA , Demência Frontotemporal/metabolismo , Degeneração Lobar Frontotemporal/metabolismo , Humanos , Microscopia de Força Atômica , Microscopia de Fluorescência , Ligação Proteica , Domínios Proteicos , Processamento de Proteína Pós-Traducional , Estrutura Secundária de Proteína , Proteína FUS de Ligação a RNA/metabolismo , Tirosina/química , Xenopus laevisRESUMO
Aberrant cell proliferation is a hallmark of cancer, including glioblastoma (GBM). Here we report that protein arginine methyltransferase (PRMT) 6 activity is required for the proliferation, stem-like properties, and tumorigenicity of glioblastoma stem cells (GSCs), a subpopulation in GBM critical for malignancy. We identified a casein kinase 2 (CK2)-PRMT6-regulator of chromatin condensation 1 (RCC1) signaling axis whose activity is an important contributor to the stem-like properties and tumor biology of GSCs. CK2 phosphorylates and stabilizes PRMT6 through deubiquitylation, which promotes PRMT6 methylation of RCC1, which in turn is required for RCC1 association with chromatin and activation of RAN. Disruption of this pathway results in defects in mitosis. EPZ020411, a specific small-molecule inhibitor for PRMT6, suppresses RCC1 arginine methylation and improves the cytotoxic activity of radiotherapy against GSC brain tumor xenografts. This study identifies a CK2α-PRMT6-RCC1 signaling axis that can be therapeutically targeted in the treatment of GBM.
Assuntos
Neoplasias Encefálicas , Carcinogênese , Proteínas de Ciclo Celular , Glioblastoma , Fatores de Troca do Nucleotídeo Guanina , Mitose/efeitos da radiação , Proteínas de Neoplasias , Proteínas Nucleares , Proteína-Arginina N-Metiltransferases , Animais , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/metabolismo , Neoplasias Encefálicas/radioterapia , Carcinogênese/genética , Carcinogênese/metabolismo , Carcinogênese/efeitos da radiação , Caseína Quinase II/genética , Caseína Quinase II/metabolismo , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Linhagem Celular Tumoral , Feminino , Glioblastoma/genética , Glioblastoma/metabolismo , Glioblastoma/radioterapia , Fatores de Troca do Nucleotídeo Guanina/genética , Fatores de Troca do Nucleotídeo Guanina/metabolismo , Células HEK293 , Humanos , Masculino , Camundongos , Mitose/genética , Proteínas de Neoplasias/genética , Proteínas de Neoplasias/metabolismo , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Proteína-Arginina N-Metiltransferases/genética , Proteína-Arginina N-Metiltransferases/metabolismo , Transdução de Sinais/genética , Transdução de Sinais/efeitos da radiação , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Arginine methylation is an influential post-translational modification occurring on histones, RNA binding proteins, and many other cellular proteins, affecting their function by altering their protein-protein and protein-nucleic acid interactions. Recently, a wealth of information has been gathered, implicating protein arginine methyltransferases (PRMTs), enzymes that deposit arginine methylation, in transcription, pre-mRNA splicing, DNA damage signaling, and immune signaling with major implications for cancer therapy, especially immunotherapy. This review summarizes this recent progress and the current state of PRMT inhibitors, some in clinical trials, as promising drug targets for cancer.
Assuntos
Arginina/química , Metilação , Neoplasias/metabolismo , Processamento de Proteína Pós-Traducional , Proteína-Arginina N-Metiltransferases/antagonistas & inibidores , Processamento Alternativo , Animais , Antígeno B7-H1/metabolismo , Sistemas CRISPR-Cas , Comunicação Celular , Linhagem Celular Tumoral , Dano ao DNA , Reparo do DNA , Inibidores Enzimáticos/farmacologia , Epigênese Genética , Histonas , Humanos , Sistema Imunitário , Imunoterapia/métodos , Camundongos , Camundongos Knockout , Proteína-Arginina N-Metiltransferases/química , Splicing de RNA , RNA Mensageiro/metabolismo , Transdução de SinaisRESUMO
PRMT5 is an essential arginine methyltransferase and a therapeutic target in MTAP-null cancers. PRMT5 uses adaptor proteins for substrate recruitment through a previously undefined mechanism. Here, we identify an evolutionarily conserved peptide sequence shared among the three known substrate adaptors (CLNS1A, RIOK1, and COPR5) and show that it is necessary and sufficient for interaction with PRMT5. We demonstrate that PRMT5 uses modular adaptor proteins containing a common binding motif for substrate recruitment, comparable with other enzyme classes such as kinases and E3 ligases. We structurally resolve the interface with PRMT5 and show via genetic perturbation that it is required for methylation of adaptor-recruited substrates including the spliceosome, histones, and ribosomal complexes. Furthermore, disruption of this site affects Sm spliceosome activity, leading to intron retention. Genetic disruption of the PRMT5-substrate adaptor interface impairs growth of MTAP-null tumor cells and is thus a site for development of therapeutic inhibitors of PRMT5.
Assuntos
Proteína-Arginina N-Metiltransferases/metabolismo , Proteína-Arginina N-Metiltransferases/fisiologia , Animais , Linhagem Celular Tumoral , Citoplasma/metabolismo , Feminino , Células HCT116 , Células HEK293 , Histonas/metabolismo , Humanos , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Canais Iônicos/metabolismo , Masculino , Metilação , Camundongos , Camundongos Nus , Proteínas Nucleares/metabolismo , Peptídeos/genética , Ligação Proteica , Processamento de Proteína Pós-Traducional , Proteínas Serina-Treonina Quinases/metabolismo , Proteína-Arginina N-Metiltransferases/genética , Spliceossomos/metabolismoRESUMO
Homozygous 5'-methylthioadenosine phosphorylase (MTAP) deletions occur in approximately 15% of human cancers. Co-deletion of MTAP and methionine adenosyltransferase 2 alpha (MAT2a) induces a synthetic lethal phenotype involving protein arginine methyltransferase 5 (PRMT5) inhibition. MAT2a inhibitors are now in clinical trials for genotypic MTAP-/- cancers, however the MTAP-/- genotype represents fewer than 2% of human colorectal cancers (CRCs), limiting the utility of MAT2a inhibitors in these and other MTAP+/+ cancers. Methylthio-DADMe-immucillin-A (MTDIA) is a picomolar transition state analog inhibitor of MTAP that renders cells enzymatically MTAP-deficient to induce the MTAP-/- phenotype. Here, we demonstrate that MTDIA and MAT2a inhibitor AG-270 combination therapy mimics synthetic lethality in MTAP+/+ CRC cell lines with similar effects in mouse xenografts and without adverse histology on normal tissues. Combination treatment is synergistic with a 104-fold increase in drug potency for inhibition of CRC cell growth in culture. Combined MTDIA and AG-270 decreases S-adenosyl-L-methionine and increases 5'-methylthioadenosine in cells. The increased intracellular methylthioadenosine:S-adenosyl-L-methionine ratio inhibits PRMT5 activity, leading to cellular arrest and apoptotic cell death by causing MDM4 alternative splicing and p53 activation. Combination MTDIA and AG-270 treatment differs from direct inhibition of PRMT5 by GSK3326595 by avoiding toxicity caused by cell death in the normal gut epithelium induced by the PRMT5 inhibitor. The combination of MTAP and MAT2a inhibitors expands this synthetic lethal approach to include MTAP+/+ cancers, especially the remaining 98% of CRCs without the MTAP-/- genotype.
Assuntos
Desoxiadenosinas , Metionina Adenosiltransferase , Neoplasias , Proteína-Arginina N-Metiltransferases , Purina-Núcleosídeo Fosforilase , S-Adenosilmetionina , Animais , Humanos , Camundongos , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Desoxiadenosinas/antagonistas & inibidores , Desoxiadenosinas/genética , Desoxiadenosinas/metabolismo , Sinergismo Farmacológico , Inibidores Enzimáticos/farmacologia , Inibidores Enzimáticos/uso terapêutico , Metionina Adenosiltransferase/antagonistas & inibidores , Metionina Adenosiltransferase/genética , Metionina Adenosiltransferase/metabolismo , Neoplasias/genética , Neoplasias/fisiopatologia , Neoplasias/terapia , Proteína-Arginina N-Metiltransferases/antagonistas & inibidores , Proteína-Arginina N-Metiltransferases/metabolismo , Proteínas Proto-Oncogênicas/genética , Proteínas Proto-Oncogênicas/metabolismo , Purina-Núcleosídeo Fosforilase/genética , Purina-Núcleosídeo Fosforilase/metabolismo , Pirrolidinas/farmacologia , Pirrolidinas/uso terapêutico , S-Adenosilmetionina/metabolismoRESUMO
The p14ARF protein is a well-known regulator of p53-dependent and p53-independent tumor-suppressive activities. In unstressed cells, p14ARF is predominantly sequestered in the nucleoli, bound to its nucleolar interaction partner NPM. Upon genotoxic stress, p14ARF undergoes an immediate redistribution to the nucleo- and cytoplasm, where it promotes activation of cell cycle arrest and apoptosis. Here, we identify p14ARF as a novel interaction partner and substrate of PRMT1 (protein arginine methyltransferase 1). PRMT1 methylates several arginine residues in the C-terminal nuclear/nucleolar localization sequence (NLS/NoLS) of p14ARF . In the absence of cellular stress, these arginines are crucial for nucleolar localization of p14ARF . Genotoxic stress causes augmented interaction between PRMT1 and p14ARF , accompanied by arginine methylation of p14ARF . PRMT1-dependent NLS/NoLS methylation promotes the release of p14ARF from NPM and nucleolar sequestration, subsequently leading to p53-independent apoptosis. This PRMT1-p14ARF cooperation is cancer-relevant and indicative for PDAC (pancreatic ductal adenocarcinoma) prognosis and chemotherapy response of pancreatic tumor cells. Our data reveal that PRMT1-mediated arginine methylation is an important trigger for p14ARF 's stress-induced tumor-suppressive function.
Assuntos
Neoplasias Pancreáticas/metabolismo , Proteína-Arginina N-Metiltransferases/metabolismo , Proteínas Repressoras/metabolismo , Proteína Supressora de Tumor p14ARF/metabolismo , Animais , Apoptose/fisiologia , Ciclo Celular/fisiologia , Linhagem Celular , Linhagem Celular Tumoral , Nucléolo Celular/metabolismo , Núcleo Celular/metabolismo , Células HEK293 , Células HeLa , Humanos , Proteínas de Neoplasias/metabolismo , Proteínas Nucleares/metabolismo , Neoplasias Pancreáticas/patologia , Prognóstico , Células Sf9 , Proteína Supressora de Tumor p53/metabolismo , Neoplasias PancreáticasRESUMO
The N6-methyladenosine (m6 A) RNA modification serves crucial functions in RNA metabolism; however, the molecular mechanisms underlying the regulation of m6 A are not well understood. Here, we establish arginine methylation of METTL14, a component of the m6 A methyltransferase complex, as a novel pathway that controls m6 A deposition in mammalian cells. Specifically, protein arginine methyltransferase 1 (PRMT1) interacts with, and methylates the intrinsically disordered C terminus of METTL14, which promotes its interaction with RNA substrates, enhances its RNA methylation activity, and is crucial for its interaction with RNA polymerase II (RNAPII). Mouse embryonic stem cells (mESCs) expressing arginine methylation-deficient METTL14 exhibit significantly reduced global m6 A levels. Transcriptome-wide m6 A analysis identified 1,701 METTL14 arginine methylation-dependent m6 A sites located in 1,290 genes involved in various cellular processes, including stem cell maintenance and DNA repair. These arginine methylation-dependent m6 A sites are associated with enhanced translation of genes essential for the repair of DNA interstrand crosslinks; thus, METTL14 arginine methylation-deficient mESCs are hypersensitive to DNA crosslinking agents. Collectively, these findings reveal important aspects of m6 A regulation and new functions of arginine methylation in RNA metabolism.
Assuntos
Adenosina/análogos & derivados , Arginina/química , Metiltransferases/metabolismo , Células-Tronco Embrionárias Murinas/metabolismo , Processamento de Proteína Pós-Traducional , Proteína-Arginina N-Metiltransferases/metabolismo , RNA Polimerase II/metabolismo , Adenosina/química , Animais , Citoplasma , Metiltransferases/química , Metiltransferases/genética , Camundongos , Células-Tronco Embrionárias Murinas/citologia , Proteína-Arginina N-Metiltransferases/genética , RNA Polimerase II/genética , TranscriptomaRESUMO
Arginine methylation is a protein posttranslational modification important for the development of skeletal muscle mass and function. Despite this, our understanding of the regulation of arginine methylation under settings of health and disease remains largely undefined. Here, we investigated the regulation of arginine methylation in skeletal muscles in response to exercise and hypertrophic growth, and in diseases involving metabolic dysfunction and atrophy. We report a limited regulation of arginine methylation under physiological settings that promote muscle health, such as during growth and acute exercise, nor in disease models of insulin resistance. In contrast, we saw a significant remodeling of asymmetric dimethylation in models of atrophy characterized by the loss of innervation, including in muscle biopsies from patients with myotrophic lateral sclerosis (ALS). Mass spectrometry-based quantification of the proteome and asymmetric arginine dimethylome of skeletal muscle from individuals with ALS revealed the largest compendium of protein changes with the identification of 793 regulated proteins, and novel site-specific changes in asymmetric dimethyl arginine (aDMA) of key sarcomeric and cytoskeletal proteins. Finally, we show that in vivo overexpression of PRMT1 and aDMA resulted in increased fatigue resistance and functional recovery in mice. Our study provides evidence for asymmetric dimethylation as a regulator of muscle pathophysiology and presents a valuable proteomics resource and rationale for numerous methylated and nonmethylated proteins, including PRMT1, to be pursued for therapeutic development in ALS.
Assuntos
Esclerose Lateral Amiotrófica , Arginina , Músculo Esquelético , Proteína-Arginina N-Metiltransferases , Músculo Esquelético/metabolismo , Músculo Esquelético/patologia , Arginina/metabolismo , Arginina/análogos & derivados , Humanos , Esclerose Lateral Amiotrófica/metabolismo , Esclerose Lateral Amiotrófica/genética , Esclerose Lateral Amiotrófica/patologia , Animais , Camundongos , Proteína-Arginina N-Metiltransferases/metabolismo , Proteína-Arginina N-Metiltransferases/genética , Masculino , Metilação , Feminino , Processamento de Proteína Pós-Traducional , Camundongos Endogâmicos C57BL , Proteoma/metabolismoRESUMO
Protein post-translation modification plays an important role in regulating DNA repair; however, the role of arginine methylation in this process is poorly understood. Here we identify the arginine methyltransferase PRMT5 as a key regulator of homologous recombination (HR)-mediated double-strand break (DSB) repair, which is mediated through its ability to methylate RUVBL1, a cofactor of the TIP60 complex. We show that PRMT5 targets RUVBL1 for methylation at position R205, which facilitates TIP60-dependent mobilization of 53BP1 from DNA breaks, promoting HR. Mechanistically, we demonstrate that PRMT5-directed methylation of RUVBL1 is critically required for the acetyltransferase activity of TIP60, promoting histone H4K16 acetylation, which facilities 53BP1 displacement from DSBs. Interestingly, RUVBL1 methylation did not affect the ability of TIP60 to facilitate ATM activation. Taken together, our findings reveal the importance of PRMT5-mediated arginine methylation during DSB repair pathway choice through its ability to regulate acetylation-dependent control of 53BP1 localization.
Assuntos
Proteínas de Transporte/metabolismo , Quebras de DNA de Cadeia Dupla , DNA Helicases/metabolismo , Histona Acetiltransferases/metabolismo , Processamento de Proteína Pós-Traducional , Proteína-Arginina N-Metiltransferases/metabolismo , Reparo de DNA por Recombinação , ATPases Associadas a Diversas Atividades Celulares , Acetilação , Animais , Arginina , Proteínas Mutadas de Ataxia Telangiectasia/metabolismo , Proteínas de Transporte/genética , DNA Helicases/genética , Instabilidade Genômica , Células HEK293 , Células HeLa , Histona Acetiltransferases/genética , Histonas/metabolismo , Humanos , Lisina Acetiltransferase 5 , Metilação , Camundongos , Camundongos Transgênicos , Proteína-Arginina N-Metiltransferases/genética , Interferência de RNA , Fatores de Tempo , Transfecção , Proteína 1 de Ligação à Proteína Supressora de Tumor p53/genética , Proteína 1 de Ligação à Proteína Supressora de Tumor p53/metabolismoRESUMO
Maintaining genomic stability is a prerequisite for proliferating NPCs to ensure genetic fidelity. Though histone arginine methylation has been shown to play important roles in safeguarding genomic stability, the underlying mechanism during brain development is not fully understood. Protein arginine N-methyltransferase 5 (PRMT5) is a type II protein arginine methyltransferase that plays a role in transcriptional regulation. Here, we identify PRMT5 as a key regulator of DNA repair in response to double-strand breaks (DSBs) during NPC proliferation. Prmt5F/F; Emx1-Cre (cKO-Emx1) mice show a distinctive microcephaly phenotype, with partial loss of the dorsal medial cerebral cortex and complete loss of the corpus callosum and hippocampus. This phenotype is resulted from DSBs accumulation in the medial dorsal cortex followed by cell apoptosis. Both RNA sequencing and in vitro DNA repair analyses reveal that PRMT5 is required for DNA homologous recombination (HR) repair. PRMT5 specifically catalyzes H3R2me2s in proliferating NPCs in the developing mouse brain to enhance HR-related gene expression during DNA repair. Finally, overexpression of BRCA1 significantly rescues DSBs accumulation and cell apoptosis in PRMT5-deficient NSCs. Taken together, our results show that PRMT5 maintains genomic stability by regulating histone arginine methylation in proliferating NPCs.
Assuntos
Células-Tronco Neurais , Reparo de DNA por Recombinação , Animais , Camundongos , Arginina/metabolismo , Reparo do DNA , Instabilidade Genômica , Genômica , Histonas/genética , Histonas/metabolismo , Células-Tronco Neurais/metabolismo , Proteína-Arginina N-Metiltransferases/genética , Proteína-Arginina N-Metiltransferases/metabolismoRESUMO
Drug resistance remains a major challenge in cancer treatment, necessitating the development of novel strategies to overcome it. Protein arginine methyltransferases (PRMTs) are enzymes responsible for epigenetic arginine methylation, which regulates various biological and pathological processes, as a result, they are attractive therapeutic targets for overcoming anti-cancer drug resistance. The ongoing development of small molecules targeting PRMTs has resulted in the generation of chemical probes for modulating most PRMTs and facilitated clinical treatment for the most advanced oncology targets, including PRMT1 and PRMT5. In this review, we summarize various mechanisms underlying protein arginine methylation and the roles of specific PRMTs in driving cancer drug resistance. Furthermore, we highlight the potential clinical implications of PRMT inhibitors in decreasing cancer drug resistance. PRMTs promote the formation and maintenance of drug-tolerant cells via several mechanisms, including altered drug efflux transporters, autophagy, DNA damage repair, cancer stem cell-related function, epithelial-mesenchymal transition, and disordered tumor microenvironment. Multiple preclinical and ongoing clinical trials have demonstrated that PRMT inhibitors, particularly PRMT5 inhibitors, can sensitize cancer cells to various anti-cancer drugs, including chemotherapeutic, targeted therapeutic, and immunotherapeutic agents. Combining PRMT inhibitors with existing anti-cancer strategies will be a promising approach for overcoming anti-cancer drug resistance. Furthermore, enhanced knowledge of the complex functions of arginine methylation and PRMTs in drug resistance will guide the future development of PRMT inhibitors and may help identify new clinical indications.
Assuntos
Antineoplásicos , Neoplasias , Humanos , Proteína-Arginina N-Metiltransferases/genética , Proteína-Arginina N-Metiltransferases/metabolismo , Proteína-Arginina N-Metiltransferases/uso terapêutico , Antineoplásicos/farmacologia , Antineoplásicos/uso terapêutico , Neoplasias/tratamento farmacológico , Neoplasias/genética , Inibidores Enzimáticos/farmacologia , Inibidores Enzimáticos/uso terapêutico , Arginina/metabolismo , Arginina/uso terapêutico , Microambiente Tumoral , Proteínas Repressoras/uso terapêuticoRESUMO
Transcriptional repression drives feedback loops that are central to the generation of circadian (â¼24-h) rhythms. In mammals, circadian repression of circadian locomotor output cycles kaput, and brain and muscle ARNT-like 1 (CLOCK:BMAL1)-mediated transcription is provided by a complex formed by PERIOD (PER) and CRYPTOCHROME (CRY) proteins. PER initiates transcriptional repression by binding CLK:BMAL1, which ultimately results in their removal from DNA. Although PER's ability to repress transcription is widely recognized, how PER binding triggers repression by removing CLK:BMAL1 from DNA is not known. Here, we use the monarch butterfly as a model system to address this problem because it harbors a simplified version of the CLK:BMAL1-activated circadian clock present in mammals. We report that an intact CLOCK mouse exon 19 homologous region (CLKe19r) and the histone methyltransferase TRITHORAX (TRX) are both necessary for monarch CLK:BMAL1-mediated transcriptional activation, CLK-PER interaction, and PER repression. Our results show that TRX catalytic activity is essential for CLK-PER interaction and PER repression via the methylation of a single arginine methylation site (R45) on heat shock protein 68 (HSP68). Our study reveals TRX and HSP68 as essential links between circadian activation and PER-mediated repression and suggests a potential conserved clock function for HSPs in eukaryotes.
Assuntos
Arginina/metabolismo , Borboletas/fisiologia , Proteínas Cromossômicas não Histona/metabolismo , Ritmo Circadiano , Proteínas de Choque Térmico/metabolismo , Proteínas Circadianas Period/metabolismo , Sequência de Aminoácidos , Animais , Ritmo Circadiano/genética , Sequência Conservada , Éxons , Proteínas de Choque Térmico/genética , Peptídeos e Proteínas de Sinalização Intracelular , Metilação , Modelos Biológicos , Ativação TranscricionalRESUMO
Protein arginine methylations are important post-translational modifications (PTMs) in eukaryotes, regulating many biological processes. However, traditional collision-based mass spectrometry methods inevitably cause neutral losses of methylarginines, preventing the deep mining of biologically important sites. Herein we developed an optimized mass spectrometry workflow based on electron-transfer dissociation (ETD) with supplemental activation for proteomic profiling of arginine methylation in human cells. Using symmetric dimethylarginine (sDMA) as an example, we show that the ETD-based optimized workflow significantly improved the identification and site localization of sDMA. Quantitative proteomics identified 138 novel sDMA sites as potential PRMT5 substrates in HeLa cells. Further biochemical studies on SERBP1, a newly identified PRMT5 substrate, confirmed the coexistence of sDMA and asymmetric dimethylarginine in the central RGG/RG motif, and loss of either methylation caused increased the recruitment of SERBP1 to stress granules under oxidative stress. Overall, our optimized workflow not only enabled the identification and localization of extensive, nonoverlapping sDMA sites in human cells but also revealed novel PRMT5 substrates whose sDMA may play potentially important biological functions.
Assuntos
Arginina , Proteômica , Humanos , Células HeLa , Arginina/metabolismo , Processamento de Proteína Pós-Traducional , Metilação , Proteína-Arginina N-Metiltransferases/genética , Proteína-Arginina N-Metiltransferases/metabolismoRESUMO
Communication between neurons relies on neurotransmission that takes place at synapses. Excitatory synapses are located primarily on dendritic spines that possess diverse morphologies, ranging from elongated filopodia to mushroom-shaped spines. Failure in the proper development of dendritic spines has detrimental consequences on neuronal connectivity, but the molecular mechanism that controls the balance of filopodia and mushroom spines is not well understood. G3BP1 is the key RNA-binding protein that assembles the stress granules in non-neuronal cells to adjust protein synthesis upon exogenous stress. Emerging evidence suggests that the biological significance of G3BP1 extends beyond its role in stress response, especially in the nervous system. However, the mechanism underlying the regulation and function of G3BP1 in neurons remains elusive. Here we found that G3BP1 suppresses protein synthesis and binds to the translation initiation factor eIF4E via its NTF2-like domain. Notably, the over-production of filopodia caused by G3BP1 depletion can be alleviated by blocking the formation of the translation initiation complex. We further found that the interaction of G3BP1 with eIF4E is regulated by arginine methylation. Knockdown of the protein arginine methyltransferase PRMT8 leads to elevated protein synthesis and filopodia production, which is reversed by the expression of methylation-mimetic G3BP1. Our study, therefore, reveals arginine methylation as a key regulatory mechanism of G3BP1 during dendritic spine morphogenesis and identifies eIF4E as a novel downstream target of G3BP1 in neuronal development independent of stress response.
Assuntos
DNA Helicases , Espinhas Dendríticas , Fator de Iniciação 4E em Eucariotos , Neurônios , Arginina/metabolismo , Proteínas de Transporte/metabolismo , Espinhas Dendríticas/metabolismo , DNA Helicases/metabolismo , Hipocampo/metabolismo , Metilação , Neurônios/metabolismo , Proteínas de Ligação a Poli-ADP-Ribose/genética , Proteínas de Ligação a Poli-ADP-Ribose/metabolismo , RNA Helicases/genética , RNA Helicases/metabolismo , Proteínas com Motivo de Reconhecimento de RNA/genética , Proteínas com Motivo de Reconhecimento de RNA/metabolismo , Animais , Ratos , Fator de Iniciação 4E em Eucariotos/metabolismoRESUMO
The transcription factor methylated c-Myc heterodimerizes with MAX to modulate gene expression, and plays an important role in energy metabolism in kidney injury but the exact mechanism remains unclear. Mitochondrial solute transporter Slc25a24 imports ATP into mitochondria and is central to energy metabolism. Gene Expression Omnibus data analysis reveals Slc25a24 and c-Myc are consistently upregulated in all the acute kidney injury (AKI) cells. Pearson correlation analysis also shows that Slc25a24 and c-Myc are strongly correlated (â´ > 0.9). Mutant arginine methylated c-Myc (R299A and R346A) reduced its combination with MAX when compared with the wild type of c-Myc. On the other hand, the Slc25a24 levels were also correspondingly reduced, which induced the downregulation of ATP production. The results promoted reactive oxygen species (ROS) production and mitophagy generation. The study revealed that the c-Myc overexpression manifested the most pronounced mitochondrial DNA depletion. Additionally, the varied levels of mitochondrial proteins like TIM23, TOM20, and PINK1 in each group, particularly the elevated levels of PINK1 in AKI model groups and lower levels of TIM23 and TOM20 in the c-Myc overexpression group, suggest potential disruptions in mitochondrial dynamics and homeostasis, indicating enhanced mitophagy or mitochondrial loss. Therefore, arginine-methylated c-Myc affects mouse kidney injury by regulating mitochondrial ATP and ROS, and mitophagy via Slc25a24.
Assuntos
Injúria Renal Aguda , Proteínas de Ligação ao Cálcio , Proteínas de Transporte da Membrana Mitocondrial , Mitofagia , Proteínas Proto-Oncogênicas c-myc , Animais , Camundongos , Injúria Renal Aguda/genética , Injúria Renal Aguda/metabolismo , Trifosfato de Adenosina/metabolismo , Mitocôndrias/metabolismo , Proteínas Quinases/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Ubiquitina-Proteína Ligases/metabolismo , Proteínas de Transporte da Membrana Mitocondrial/metabolismo , Proteínas de Ligação ao Cálcio/metabolismo , Proteínas Proto-Oncogênicas c-myc/metabolismoRESUMO
Protein arginine methyltransferases (PRMTs) play critical roles in Plasmodium falciparum, a protozoan causing the deadliest form of malaria, making them potential targets for novel antimalarial drugs. Here, we screened 11 novel PRMT inhibitors against P. falciparum asexual growth and found that onametostat, an inhibitor for type II PRMTs, exhibited strong antimalarial activity with a half-maximal inhibitory concentration (IC50) value of 1.69 ± 0.04 µM. In vitro methyltransferase activities of purified PfPRMT5 were inhibited by onametostat, and a shift of IC50 to onametostat was found in the PfPRTM5 disruptant parasite line, indicating that PfPRTM5 is the primary target of onametostat. Consistent with the function of PfPRMT5 in mediating symmetric dimethylation of histone H3R2 (H3R2me2s) and in regulating invasion-related genes, onametostat treatment led to the reduction of H3R2me2s level in P. falciparum and caused the defects on the parasite's invasion of red blood cells. This study provides a starting point for identifying specific PRMT inhibitors with the potential to serve as novel antimalarial drugs.
RESUMO
BACKGROUND & AIMS: Dysregulation of alternative splicing is implicated in many human diseases, and understanding the genetic variation underlying transcript splicing is essential to dissect the molecular mechanisms of cancers. We aimed to provide a comprehensive functional dissection of splicing quantitative trait loci (sQTLs) in cancer and focus on elucidating its distinct role in colorectal cancer (CRC) mechanisms. METHODS: We performed a comprehensive sQTL analysis to identify genetic variants that control messenger RNA splicing across 33 cancer types from The Cancer Genome Atlas and independently validated in our 154 CRC tissues. Then, large-scale, multicenter, multi-ethnic case-control studies (34,585 cases and 76,023 controls) were conducted to examine the association of these sQTLs with CRC risk. A series of biological experiments in vitro and in vivo were performed to investigate the potential mechanisms of the candidate sQTLs and target genes. RESULTS: The molecular characterization of sQTL revealed its distinct role in cancer susceptibility. Tumor-specific sQTL further showed better response to cancer development. In addition, functionally informed polygenic risk score highlighted the potentiality of sQTLs in the CRC prediction. Complemented by large-scale population studies, we identified that the risk allele (T) of a multi-ancestry-associated sQTL rs61746794 significantly increased the risk of CRC in Chinese (odds ratio, 1.20; 95% CI, 1.12-1.29; P = 8.82 × 10-7) and European (odds ratio, 1.11; 95% CI, 1.07-1.16; P = 1.13 × 10-7) populations. rs61746794-T facilitated PRMT7 exon 16 splicing mediated by the RNA-binding protein PRPF8, thus increasing the level of canonical PRMT7 isoform (PRMT7-V2). Overexpression of PRMT7-V2 significantly enhanced the growth of CRC cells and xenograft tumors compared with PRMT7-V1. Mechanistically, PRMT7-V2 functions as an epigenetic writer that catalyzes the arginine methylation of H4R3 and H3R2, subsequently regulating diverse biological processes, including YAP, AKT, and KRAS pathway. A selective PRMT7 inhibitor, SGC3027, exhibited antitumor effects on human CRC cells. CONCLUSIONS: Our study provides an informative sQTLs resource and insights into the regulatory mechanisms linking splicing variants to cancer risk and serving as biomarkers and therapeutic targets.
RESUMO
Murine endogenous retrovirus with leucine tRNA primer, also known as MERVL, is expressed during zygotic genome activation in mammalian embryos. Here we show that protein arginine N-methyltransferase 6 (Prmt6) forms a chimeric transcript with MT2B2, one of the long terminal repeat sequences of murine endogenous retrovirus with leucine tRNA primer, and is translated into an elongated chimeric protein (PRMT6MT2B2) whose function differs from that of the canonical PRMT6 protein (PRMT6CAN) in mouse preimplantation embryos. Overexpression of PRMT6CAN in fibroblast cells increased asymmetric dimethylation of the third arginine residue of both histone H2A (H2AR3me2a) and histone H4 (H4R3me2a), while overexpression of PRMT6MT2B2 increased only H2AR3me2a. In addition, overexpression of PRMT6MT2B2 in one blastomere of mouse two-cell embryos promoted cell proliferation and differentiation of the blastomere into epiblast cells at the blastocyst stage, while overexpression of PRMT6CAN repressed cell proliferation. This is the first report of the translation of a chimeric protein (PRMT6MT2B2) in mouse preimplantation embryos. Our results suggest that analyzing chimeric transcripts with murine endogenous retrovirus with leucine tRNA primer will provide insight into the relationship between zygotic genome activation and subsequent intra- and extra-cellular lineage determination.
Assuntos
Retrovirus Endógenos , Animais , Camundongos , Retrovirus Endógenos/genética , Leucina/metabolismo , Metilação , Histonas/genética , Histonas/metabolismo , Blastocisto/metabolismo , Arginina , Proteínas Recombinantes de Fusão/genética , RNA de Transferência/metabolismo , Mamíferos/genéticaRESUMO
The infectious bursal diseases virus (IBDV) polymerase, VP1 protein, is responsible for transcription, initial translation and viral genomic replication. Knowledge about the new kind of post-translational modification of VP1 supports identification of novel drugs against the virus. Because the arginine residue is known to be methylated by protein arginine methyltransferase (PRMT) enzyme, we investigated whether IBDV VP1 is a substrate for known PRMTs. In this study, we show that VP1 is specifically associated with and methylated by PRMT5 at the arginine 426 (R426) residue. IBDV infection causes the accumulation of PRMT5 in the cytoplasm, which colocalizes with VP1 as a punctate structure. In addition, ectopic expression of PRMT5 significantly enhances the viral replication. In the presence of PMRT5, enzyme inhibitor and knockout of PRMT5 remarkably decreased viral replication. The polymerase activity of VP1 was severely damaged when R426 mutated to alanine, resulting in impaired viral replication. Our study reports a novel form of post-translational modification of VP1, which supports its polymerase function to facilitate the viral replication. IMPORTANCE Post-translational modification of infectious bursal disease virus (IBDV) VP1 is important for the regulation of its polymerase activity. Investigation of the significance of specific modification of VP1 can lead to better understanding of viral replication and can probably also help in identifying novel targets for antiviral compounds. Our work demonstrates the molecular mechanism of VP1 methylation mediated by PRMT5, which is critical for viral polymerase activity, as well as viral replication. Our study expands a novel insight into the function of arginine methylation of VP1, which might be useful for limiting the replication of IBDV.