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1.
Mol Cell ; 80(1): 140-155.e6, 2020 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-33007254

RESUMO

The tissue-specific deployment of highly extended neural 3' UTR isoforms, generated by alternative polyadenylation (APA), is a broad and conserved feature of metazoan genomes. However, the factors and mechanisms that control neural APA isoforms are not well understood. Here, we show that three ELAV/Hu RNA binding proteins (Elav, Rbp9, and Fne) have similar capacities to induce a lengthened 3' UTR landscape in an ectopic setting. These factors promote accumulation of chromatin-associated, 3' UTR-extended, nascent transcripts, through inhibition of proximal polyadenylation site (PAS) usage. Notably, Elav represses an unannotated splice isoform of fne, switching the normally cytoplasmic Fne toward the nucleus in elav mutants. We use genomic profiling to reveal strong and broad loss of neural APA in elav/fne double mutant CNS, the first genetic background to largely abrogate this distinct APA signature. Overall, we demonstrate how regulatory interplay and functionally overlapping activities of neural ELAV/Hu RBPs drives the neural APA landscape.


Assuntos
Regiões 3' não Traduzidas/genética , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/genética , Proteínas ELAV/metabolismo , Neurônios/metabolismo , Processamento Alternativo/genética , Motivos de Aminoácidos , Animais , Linhagem Celular , Núcleo Celular/metabolismo , Proteínas ELAV/química , Larva/metabolismo , Mutação/genética , Poli A/metabolismo , Isoformas de Proteínas/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo
2.
Anticancer Res ; 40(10): 5545-5556, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32988878

RESUMO

BACKGROUND/AIM: The p38 family of mitogen-activated protein kinases (MAPK) includes four isoforms: p38α, -ß, -γ and -δ. The aim of this study was to elucidate possible functions of p38α and p38ß in human pancreatic cancer. MATERIALS AND METHODS: Isoform expression was determined in seven human pancreatic cancer cell lines. After shRNA based selective knockdown of p38α and p38ß, in vitro growth and migration as well as in vivo tumorigenicity were assessed. RESULTS: All pancreatic cancer cells expressed p38 isoforms. Knockdown of p38α and p38ß inhibited in vitro growth. Migration was markedly reduced in p38α shRNA expressing clones, but not altered by p38ß knockdown. While in vivo inhibition of p38ß decreased tumor formation and growth, the knockdown of p38α significantly enhanced tumorigenicity. CONCLUSION: p38 MAPKs may exert isoform specific functions in pancreatic cancer. Selective targeting may contribute to individualized treatment of pancreatic cancer in the future.


Assuntos
Proteína Quinase 11 Ativada por Mitógeno/genética , Proteína Quinase 14 Ativada por Mitógeno/genética , Neoplasias Pancreáticas/genética , Proteínas Quinases p38 Ativadas por Mitógeno/genética , Carcinogênese/genética , Linhagem Celular Tumoral , Regulação Neoplásica da Expressão Gênica/genética , Humanos , Neoplasias Pancreáticas/patologia , Fosforilação , Isoformas de Proteínas/genética , RNA Interferente Pequeno/genética
3.
Adv Exp Med Biol ; 1255: 165-173, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32949399

RESUMO

PI3K inhibitors are a common area of research in finding a successful treatment of cancer. The PI3K pathway is important for cell growth, apoptosis, cell metabolism, cell survival, and a multitude of other functions. There are multiple isoforms of PI3K that can be broken down into three categories: class I, II, and III. Each isoform has at least one subunit that helps with the functionality of the isoform. Mutations found in the PI3K isoforms are commonly seen in many different types of cancer and the use of inhibitors is being tested to stop the cell survival of cancer cells. Individual PI3K inhibitors have shown some inhibition of the pathway; however, there is room for improvement. To better treat cancer, PI3K inhibitors are being combined with other pathway inhibitors. These combination therapies have shown better results with cancer treatments. Both the monotherapy and dual therapy treatments are still currently being studied and data collected to better understand cancer and other treatment options.


Assuntos
Neoplasias/tratamento farmacológico , Neoplasias/enzimologia , Fosfatidilinositol 3-Quinases/química , Fosfatidilinositol 3-Quinases/metabolismo , Inibidores de Fosfoinositídeo-3 Quinase/farmacologia , Inibidores de Fosfoinositídeo-3 Quinase/uso terapêutico , Humanos , Isoformas de Proteínas/antagonistas & inibidores
4.
Nat Commun ; 11(1): 4025, 2020 08 12.
Artigo em Inglês | MEDLINE | ID: mdl-32788667

RESUMO

Droplet-based high throughput single cell sequencing techniques tremendously advanced our insight into cell-to-cell heterogeneity. However, those approaches only allow analysis of one extremity of the transcript after short read sequencing. In consequence, information on splicing and sequence heterogeneity is lost. To overcome this limitation, several approaches that use long-read sequencing were introduced recently. Yet, those techniques are limited by low sequencing depth and/or lacking or inaccurate assignment of unique molecular identifiers (UMIs), which are critical for elimination of PCR bias and artifacts. We introduce ScNaUmi-seq, an approach that combines the high throughput of Oxford Nanopore sequencing with an accurate cell barcode and UMI assignment strategy. UMI guided error correction allows to generate high accuracy full length sequence information with the 10x Genomics single cell isolation system at high sequencing depths. We analyzed transcript isoform diversity in embryonic mouse brain and show that ScNaUmi-seq allows defining splicing and SNVs (RNA editing) at a single cell level.


Assuntos
Sequenciamento de Nucleotídeos em Larga Escala/métodos , Sequenciamento por Nanoporos , Nanoporos , Transcriptoma , Animais , Encéfalo , Expressão Gênica , Perfilação da Expressão Gênica , Genômica , Camundongos , Camundongos Endogâmicos C57BL , Isoformas de Proteínas , Receptores de AMPA/genética , Análise de Sequência de DNA/métodos , Análise de Sequência de RNA/métodos
5.
PLoS Genet ; 16(7): e1008923, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32735630

RESUMO

Mitochondrial translation defects can be due to mutations affecting mitochondrial- or nuclear-encoded components. The number of known nuclear genes involved in mitochondrial translation has significantly increased in the past years. RCC1L (WBSCR16), a putative GDP/GTP exchange factor, has recently been described to interact with the mitochondrial large ribosomal subunit. In humans, three different RCC1L isoforms have been identified that originate from alternative splicing but share the same N-terminus, RCC1LV1, RCC1LV2 and RCC1LV3. All three isoforms were exclusively localized to mitochondria, interacted with its inner membrane and could associate with homopolymeric oligos to different extent. Mitochondrial immunoprecipitation experiments showed that RCC1LV1 and RCC1LV3 associated with the mitochondrial large and small ribosomal subunit, respectively, while no significant association was observed for RCC1LV2. Overexpression and silencing of RCC1LV1 or RCC1LV3 led to mitoribosome biogenesis defects that resulted in decreased translation. Indeed, significant changes in steady-state levels and distribution on isokinetic sucrose gradients were detected not only for mitoribosome proteins but also for GTPases, (GTPBP10, ERAL1 and C4orf14), and pseudouridylation proteins, (TRUB2, RPUSD3 and RPUSD4). All in all, our data suggest that RCC1L is essential for mitochondrial function and that the coordination of at least two isoforms is essential for proper ribosomal assembly.


Assuntos
GTP Fosfo-Hidrolases/genética , Proteínas Mitocondriais/genética , Isoformas de Proteínas/genética , Proteínas Ribossômicas/genética , Proteínas de Ligação ao GTP/genética , Humanos , Imunoprecipitação , Proteínas de Membrana/genética , Mitocôndrias/genética , Ribossomos Mitocondriais/metabolismo , Proteínas Monoméricas de Ligação ao GTP/genética , Biossíntese de Proteínas/genética , RNA/genética , Proteínas de Ligação a RNA/genética
6.
Nat Commun ; 11(1): 4067, 2020 08 13.
Artigo em Inglês | MEDLINE | ID: mdl-32792493

RESUMO

The brain is organized morphologically and functionally into a columnar structure. According to the radial unit hypothesis, neurons from the same lineage form a radial unit that contributes to column formation. However, the molecular mechanisms that link neuronal lineage and column formation remain elusive. Here, we show that neurons from the same lineage project to different columns under control of Down syndrome cell adhesion molecule (Dscam) in the fly brain. Dscam1 is temporally expressed in newly born neuroblasts and is inherited by their daughter neurons. The transient transcription of Dscam1 in neuroblasts enables the expression of the same Dscam1 splice isoform within cells of the same lineage, causing lineage-dependent repulsion. In the absence of Dscam1 function, neurons from the same lineage project to the same column. When the splice diversity of Dscam1 is reduced, column formation is significantly compromised. Thus, Dscam1 controls column formation through lineage-dependent repulsion.


Assuntos
Moléculas de Adesão Celular/metabolismo , Proteínas de Drosophila/metabolismo , Neurônios/citologia , Neurônios/metabolismo , Isoformas de Proteínas/metabolismo , Animais , Axônios/metabolismo , Moléculas de Adesão Celular/genética , Células Cultivadas , Proteínas de Drosophila/genética , Drosophila melanogaster , Células-Tronco Neurais/citologia , Células-Tronco Neurais/metabolismo , Neurogênese/genética , Neurogênese/fisiologia , Isoformas de Proteínas/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa
7.
PLoS One ; 15(8): e0233673, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32750050

RESUMO

Computational algorithms are often used to assess pathogenicity of Variants of Uncertain Significance (VUS) that are found in disease-associated genes. Most computational methods include analysis of protein multiple sequence alignments (PMSA), assessing interspecies variation. Careful validation of PMSA-based methods has been done for relatively few genes, partially because creation of curated PMSAs is labor-intensive. We assessed how PMSA-based computational tools predict the effects of the missense changes in the APC gene, in which pathogenic variants cause Familial Adenomatous Polyposis. Most Pathogenic or Likely Pathogenic APC variants are protein-truncating changes. However, public databases now contain thousands of variants reported as missense. We created a curated APC PMSA that contained >3 substitutions/site, which is large enough for statistically robust in silico analysis. The creation of the PMSA was not easily automated, requiring significant querying and computational analysis of protein and genome sequences. Of 1924 missense APC variants in the NCBI ClinVar database, 1800 (93.5%) are reported as VUS. All but two missense variants listed as P/LP occur at canonical splice or Exonic Splice Enhancer sites. Pathogenicity predictions by five computational tools (Align-GVGD, SIFT, PolyPhen2, MAPP, REVEL) differed widely in their predictions of Pathogenic/Likely Pathogenic (range 17.5-75.0%) and Benign/Likely Benign (range 25.0-82.5%) for APC missense variants in ClinVar. When applied to 21 missense variants reported in ClinVar and securely classified as Benign, the five methods ranged in accuracy from 76.2-100%. Computational PMSA-based methods can be an excellent classifier for variants of some hereditary cancer genes. However, there may be characteristics of the APC gene and protein that confound the results of in silico algorithms. A systematic study of these features could greatly improve the automation of alignment-based techniques and the use of predictive algorithms in hereditary cancer genes.


Assuntos
Proteína da Polipose Adenomatosa do Colo/genética , Polipose Adenomatosa do Colo/genética , Genes APC , Mutação de Sentido Incorreto , Algoritmos , Sequência de Aminoácidos , Biologia Computacional/métodos , Simulação por Computador , Bases de Dados de Proteínas , Elementos Facilitadores Genéticos , Evolução Molecular , Éxons , Variação Genética , Humanos , Filogenia , Isoformas de Proteínas/genética , Sítios de Splice de RNA , Alinhamento de Sequência/estatística & dados numéricos
8.
J Chromatogr A ; 1626: 461344, 2020 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-32797824

RESUMO

The applicability of capillary zone electrophoresis (CZE) for the separation of the deamidated forms of insulin has been studied. 50 mM NH4Ac (pH=9) with 20 % v/v isopropylalcohol was found optimal for efficient separation of insulin from its even 10 deamidated forms. The developed method was efficiently applied for monitoring the degradation rate of insulin and the formation of different deamidation isoforms. Two months after the acidification more than thirty peaks can be observed in the electropherogram, because degradation products other than deamidated components were formed as well. The recorded mass spectra enabled us to assign the exact mass of the components, and thus the identification of insulin isoforms could be accomplished. We think that this study provides useful information on how the determination of several deamidation forms can be carried out with CE-MS, but the identification of the exact position of deamidation sites in the insulin molecule remains a challenge.


Assuntos
Eletroforese Capilar/métodos , Insulinas/análise , Humanos , Concentração de Íons de Hidrogênio , Espectrometria de Massas , Isoformas de Proteínas/análise , Temperatura
9.
Gene ; 760: 145021, 2020 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-32763489

RESUMO

Human B cell activating factor (TNFSF13B, BAFF) is a tumor necrosis factor superfamily member. Binding its unique receptor (TNFRSF13C, BAFF-R) mediates gene expression and cell survival in B cells via activation of NFκB pathway. Furthermore, there is data indicating a role in T cell function. A functionally inhibitory isoform (ΔBAFF) resulting from the deletion of exon 3 in the TNFSF13B pre-RNA has already been reported. However, data on the complexity of post-transcriptional regulation is scarce. Here, we report molecular cloning of nine TNFSF13B transcript variants resulting from alternative splicing of the TNFSF13B pre-mRNA including BAFFX1. This variant is characterized by a partial retention of intron 3 of the TNFSF13B gene causing the appearance of a premature stop codon. We demonstrate the expression of the corresponding BAFFX1 protein in Jurkat T cells, in ex vivo human immune cells and in human tonsillar tissue. Thereby we contribute to the understanding of TNFSF13B gene regulation and reveal that BAFF is regulated through a post-transcriptional mechanism to a greater extent than reported to date.


Assuntos
Fator Ativador de Células B/genética , Fator Ativador de Células B/imunologia , Processamento Alternativo/genética , Fator Ativador de Células B/metabolismo , Linfócitos B/metabolismo , Éxons , Expressão Gênica , Humanos , NF-kappa B/metabolismo , Isoformas de Proteínas/genética , Precursores de RNA/metabolismo , Linfócitos T/metabolismo , Fator de Necrose Tumoral alfa/genética
10.
Cells ; 9(9)2020 08 24.
Artigo em Inglês | MEDLINE | ID: mdl-32847031

RESUMO

Following influenza infection, rs2248374-G ERAP2 expressing cells may transcribe an alternative spliced isoform: ERAP2/Iso3. This variant, unlike ERAP2-wt, is unable to trim peptides to be loaded on MHC class I molecules, but it can still dimerize with both ERAP2-wt and ERAP1-wt, thus contributing to profiling an alternative cellular immune-peptidome. In order to verify if the expression of ERAP2/Iso3 may be induced by other pathogens, PBMCs and MDMs isolated from 20 healthy subjects were stimulated with flu, LPS, CMV, HIV-AT-2, SARS-CoV-2 antigens to analyze its mRNA and protein expression. In parallel, Calu3 cell lines and PBMCs were in vitro infected with growing doses of SARS-CoV-2 (0.5, 5, 1000 MOI) and HIV-1BAL (0.1, 1, and 10 ng p24 HIV-1Bal/1 × 106 PBMCs) viruses, respectively. Results showed that: (1) ERAP2/Iso3 mRNA expression can be prompted by many pathogens and it is coupled with the modulation of several determinants (cytokines, interferon-stimulated genes, activation/inhibition markers, antigen-presentation elements) orchestrating the anti-microbial immune response (Quantigene); (2) ERAP2/Iso3 mRNA is translated into a protein (western blot); (3) ERAP2/Iso3 mRNA expression is sensitive to SARS-CoV-2 and HIV-1 concentration. Considering the key role played by ERAPs in antigen processing and presentation, it is conceivable that these enzymes may be potential targets and modulators of the pathogenicity of infectious diseases and further analyses are needed to define the role played by the different isoforms.


Assuntos
Aminopeptidases/genética , Betacoronavirus/imunologia , Infecções por Coronavirus/genética , Imunização/métodos , Leucócitos Mononucleares/virologia , Macrófagos/virologia , Pneumonia Viral/genética , Isoformas de Proteínas/genética , Apresentação do Antígeno/genética , Doadores de Sangue , Linhagem Celular Tumoral , Infecções por Coronavirus/virologia , Expressão Gênica/imunologia , Genótipo , Infecções por HIV/genética , Infecções por HIV/virologia , HIV-1/imunologia , Humanos , Leucócitos Mononucleares/metabolismo , Macrófagos/metabolismo , Antígenos de Histocompatibilidade Menor/genética , Pandemias , Pneumonia Viral/virologia , Polimorfismo de Nucleotídeo Único , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Transcrição Genética/imunologia
11.
Nat Struct Mol Biol ; 27(8): 763-767, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32647346

RESUMO

SARS-CoV-2 is thought to have emerged from bats, possibly via a secondary host. Here, we investigate the relationship of spike (S) glycoprotein from SARS-CoV-2 with the S protein of a closely related bat virus, RaTG13. We determined cryo-EM structures for RaTG13 S and for both furin-cleaved and uncleaved SARS-CoV-2 S; we compared these with recently reported structures for uncleaved SARS-CoV-2 S. We also biochemically characterized their relative stabilities and affinities for the SARS-CoV-2 receptor ACE2. Although the overall structures of human and bat virus S proteins are similar, there are key differences in their properties, including a more stable precleavage form of human S and about 1,000-fold tighter binding of SARS-CoV-2 to human receptor. These observations suggest that cleavage at the furin-cleavage site decreases the overall stability of SARS-CoV-2 S and facilitates the adoption of the open conformation that is required for S to bind to the ACE2 receptor.


Assuntos
Betacoronavirus/genética , Interações Hospedeiro-Patógeno/genética , Peptidil Dipeptidase A/química , Receptores Virais/química , Glicoproteína da Espícula de Coronavírus/química , Animais , Betacoronavirus/metabolismo , Betacoronavirus/ultraestrutura , Sítios de Ligação , Quirópteros/virologia , Infecções por Coronavirus/virologia , Microscopia Crioeletrônica , Evolução Molecular , Furina/química , Expressão Gênica , Células HEK293 , Humanos , Modelos Moleculares , Pandemias , Peptidil Dipeptidase A/genética , Peptidil Dipeptidase A/metabolismo , Pneumonia Viral/virologia , Ligação Proteica , Conformação Proteica em alfa-Hélice , Conformação Proteica em Folha beta , Domínios e Motivos de Interação entre Proteínas , Isoformas de Proteínas/química , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Estabilidade Proteica , Proteólise , Receptores Virais/genética , Receptores Virais/metabolismo , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Glicoproteína da Espícula de Coronavírus/genética , Glicoproteína da Espícula de Coronavírus/metabolismo , Homologia Estrutural de Proteína
12.
PLoS Comput Biol ; 16(7): e1007801, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32628657

RESUMO

Recent experiments with super-resolution live cell microscopy revealed that nonmuscle myosin II minifilaments are much more dynamic than formerly appreciated, often showing plastic processes such as splitting, concatenation and stacking. Here we combine sequence information, electrostatics and elasticity theory to demonstrate that the parallel staggers at 14.3, 43.2 and 72 nm have a strong tendency to splay their heads away from the minifilament, thus potentially initiating the diverse processes seen in live cells. In contrast, the straight antiparallel stagger with an overlap of 43 nm is very stable and likely initiates minifilament nucleation. Using stochastic dynamics in a newly defined energy landscape, we predict that the optimal parallel staggers between the myosin rods are obtained by a trial-and-error process in which two rods attach and re-attach at different staggers by rolling and zipping motion. The experimentally observed staggers emerge as the configurations with the largest contact times. We find that contact times increase from isoforms C to B to A, that A-B-heterodimers are surprisingly stable and that myosin 18A should incorporate into mixed filaments with a small stagger. Our findings suggest that nonmuscle myosin II minifilaments in the cell are first formed by isoform A and then convert to mixed A-B-filaments, as observed experimentally.


Assuntos
Miosina Tipo II , Eletricidade Estática , Biologia Computacional , Humanos , Modelos Moleculares , Miosina Tipo II/química , Miosina Tipo II/metabolismo , Miosina Tipo II/ultraestrutura , Conformação Proteica , Isoformas de Proteínas
13.
Proc Natl Acad Sci U S A ; 117(30): 18079-18090, 2020 07 28.
Artigo em Inglês | MEDLINE | ID: mdl-32647060

RESUMO

Ion channels in excitable cells function in macromolecular complexes in which auxiliary proteins modulate the biophysical properties of the pore-forming subunits. Hyperpolarization-activated, cyclic nucleotide-sensitive HCN4 channels are critical determinants of membrane excitability in cells throughout the body, including thalamocortical neurons and cardiac pacemaker cells. We previously showed that the properties of HCN4 channels differ dramatically in different cell types, possibly due to the endogenous expression of auxiliary proteins. Here, we report the discovery of a family of endoplasmic reticulum (ER) transmembrane proteins that associate with and modulate HCN4. Lymphoid-restricted membrane protein (LRMP, Jaw1) and inositol trisphosphate receptor-associated guanylate kinase substrate (IRAG, Mrvi1, and Jaw1L) are homologous proteins with small ER luminal domains and large cytoplasmic domains. Despite their homology, LRMP and IRAG have distinct effects on HCN4. LRMP is a loss-of-function modulator that inhibits the canonical depolarizing shift in the voltage dependence of HCN4 in response to the binding of cAMP. In contrast, IRAG causes a gain of HCN4 function by depolarizing the basal voltage dependence in the absence of cAMP. The mechanisms of action of LRMP and IRAG are independent of trafficking and cAMP binding, and they are specific to the HCN4 isoform. We also found that IRAG is highly expressed in the mouse sinoatrial node where computer modeling predicts that its presence increases HCN4 current. Our results suggest important roles for LRMP and IRAG in the regulation of cellular excitability, as tools for advancing mechanistic understanding of HCN4 channel function, and as possible scaffolds for coordination of signaling pathways.


Assuntos
Retículo Endoplasmático/metabolismo , Canais Disparados por Nucleotídeos Cíclicos Ativados por Hiperpolarização/metabolismo , Animais , Células CHO , Linhagem Celular , Cricetulus , AMP Cíclico/metabolismo , Regulação da Expressão Gênica , Humanos , Canais Disparados por Nucleotídeos Cíclicos Ativados por Hiperpolarização/química , Canais Disparados por Nucleotídeos Cíclicos Ativados por Hiperpolarização/genética , Masculino , Potenciais da Membrana/efeitos dos fármacos , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Camundongos , Modelos Biológicos , Família Multigênica , Miócitos Cardíacos/metabolismo , Fosfoproteínas/metabolismo , Ligação Proteica , Domínios e Motivos de Interação entre Proteínas , Isoformas de Proteínas , Nó Sinoatrial/fisiologia , Nó Sinoatrial/fisiopatologia
14.
Proc Natl Acad Sci U S A ; 117(29): 17409-17417, 2020 07 21.
Artigo em Inglês | MEDLINE | ID: mdl-32616567

RESUMO

Proteolytic cascades regulate immunity and development in animals, but these cascades in plants have not yet been reported. Here we report that the extracellular immune protease Rcr3 of tomato is activated by P69B and other subtilases (SBTs), revealing a proteolytic cascade regulating extracellular immunity in solanaceous plants. Rcr3 is a secreted papain-like Cys protease (PLCP) of tomato that acts both in basal resistance against late blight disease (Phytophthora infestans) and in gene-for-gene resistance against the fungal pathogen Cladosporium fulvum (syn. Passalora fulva) Despite the prevalent model that Rcr3-like proteases can activate themselves at low pH, we found that catalytically inactive proRcr3 mutant precursors are still processed into mature mRcr3 isoforms. ProRcr3 is processed by secreted P69B and other Asp-selective SBTs in solanaceous plants, providing robust immunity through SBT redundancy. The apoplastic effector EPI1 of P. infestans can block Rcr3 activation by inhibiting SBTs, suggesting that this effector promotes virulence indirectly by preventing the activation of Rcr3(-like) immune proteases. Rcr3 activation in Nicotiana benthamiana requires a SBT from a different subfamily, indicating that extracellular proteolytic cascades have evolved convergently in solanaceous plants or are very ancient in the plant kingdom. The frequent incidence of Asp residues in the cleavage region of Rcr3-like proteases in solanaceous plants indicates that activation of immune proteases by SBTs is a general mechanism, illuminating a proteolytic cascade that provides robust apoplastic immunity.


Assuntos
Lycopersicon esculentum/metabolismo , Peptídeo Hidrolases/metabolismo , Doenças das Plantas/imunologia , Imunidade Vegetal , Proteólise , Cladosporium , Lycopersicon esculentum/genética , Peptídeo Hidrolases/genética , Phytophthora infestans , Doenças das Plantas/parasitologia , Doenças das Plantas/prevenção & controle , Proteínas de Plantas/metabolismo , Isoformas de Proteínas , Virulência
15.
Anticancer Res ; 40(7): 3781-3792, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32620617

RESUMO

BACKGROUND/AIM: Canine B-cell lymphoma represents a useful in vivo model for human diffuse large B-cell lymphoma (DLBCL). Pan-Bromodomain and extra-terminal (BET) inhibition targeting BRD2/3/4 and selective inhibition of BRD4, as well as spleen tyrosine kinase (SYK) inhibition, are currently evaluated as haematologic cancer therapy. Herein, we characterized the differences in the biologic response of isoform-specific or pan-BET inhibition alone or in combination with SYK inhibition. MATERIALS AND METHODS: I-BET151 (pan-inhibitor) and AZD5153 (BRD4 inhibitor) were combined with Entospletinib (SYK inhibitor) and comparatively analysed in the canine DLBCL cell line CLBL-1. Dose- and time-dependent cellular responses were analysed by cell number, metabolic activity, apoptosis/necrosis, and cell morphology. The synergistic potential was evaluated through the Bliss independence model. RESULTS: I-BET151 and AZD5153 showed significant dose- and time-dependent inhibitory effects. Adding Entospletinib to I-BET151 or AZD5153 had no additional synergistic effects. CONCLUSION: Entospletinib did not enhance the inhibitory effects of the pan- or isoform-specific BET.


Assuntos
Indazóis/farmacologia , Linfoma Difuso de Grandes Células B/tratamento farmacológico , Proteínas Nucleares/antagonistas & inibidores , Isoformas de Proteínas/antagonistas & inibidores , Pirazinas/farmacologia , Animais , Linhagem Celular Tumoral , Cães , Compostos Heterocíclicos com 2 Anéis/farmacologia , Compostos Heterocíclicos de 4 ou mais Anéis/farmacologia , Linfoma Difuso de Grandes Células B/metabolismo , Piperazinas/farmacologia , Proteínas Serina-Treonina Quinases/metabolismo , Quinase Syk/metabolismo
16.
Tumour Biol ; 42(7): 1010428320937863, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32686600

RESUMO

Maintaining intracellular pH is crucial for preserving healthy cellular behavior and, when dysregulated, results in increased proliferation, migration, and invasion. The Na+/H+ exchanger isoform 1 is a highly regulated transmembrane antiporter that maintains pH homeostasis by exporting protons in response to intra- and extracellular signals. Activation of Na+/H+ exchanger isoform 1 is exquisitely regulated by the extracellular environment and protein cofactors, including calcineurin B homologous proteins 1 and 2. While Na+/H+ exchanger isoform 1 and calcineurin B homologous protein 1 are ubiquitously expressed, calcineurin B homologous protein 2 shows tissue-specific expression and upregulation in a variety of cancer cells. In addition, calcineurin B homologous protein 2 expression is modulated by tumorigenic extracellular conditions like low nutrients. To understand the role of calcineurin B homologous protein 2 in tumorigenesis and survival in lung cancer, we surveyed existing databases and formed a comprehensive report of Na+/H+ exchanger isoform 1, calcineurin B homologous protein 1, and calcineurin B homologous protein 2 expression in diseased and non-diseased tissues. We show that calcineurin B homologous protein 2 is upregulated during oncogenesis in many adeno and squamous carcinomas. To understand the functional role of calcineurin B homologous protein 2 upregulation, we evaluated the effect of Na+/H+ exchanger isoform 1 and calcineurin B homologous protein 2 depletion on cellular function during cancer progression in situ. Here, we show that calcineurin B homologous protein 2 functions through Na+/H+ exchanger isoform 1 to effect cell proliferation, cell migration, steady-state pHi, and anchorage-independent tumor growth. Finally, we present evidence that calcineurin B homologous protein 2 depletion in vivo has potential to reduce tumor burden in a xenograft model. Together, these data support the tumor-promoting potential of aberrant calcineurin B homologous protein 2 expression and position calcineurin B homologous protein 2 as a potential therapeutic target for the treatment of non-small cell lung cancer.


Assuntos
Calcineurina/metabolismo , Proteínas de Ligação ao Cálcio/metabolismo , Carcinoma Pulmonar de Células não Pequenas/patologia , Neoplasias Pulmonares/patologia , Trocador 1 de Sódio-Hidrogênio/metabolismo , Animais , Calcineurina/genética , Proteínas de Ligação ao Cálcio/genética , Linhagem Celular Tumoral , Movimento Celular/fisiologia , Proliferação de Células/fisiologia , Humanos , Concentração de Íons de Hidrogênio , Camundongos , Camundongos Nus , Transplante de Neoplasias , Isoformas de Proteínas/metabolismo , Transplante Heterólogo
17.
Proc Natl Acad Sci U S A ; 117(33): 20139-20148, 2020 08 18.
Artigo em Inglês | MEDLINE | ID: mdl-32727899

RESUMO

Lung cancer causes more deaths annually than any other malignancy. A subset of non-small cell lung cancer (NSCLC) is driven by amplification and overexpression or activating mutation of the receptor tyrosine kinase (RTK) ERBB2 In some contexts, notably breast cancer, alternative splicing of ERBB2 causes skipping of exon 16, leading to the expression of an oncogenic ERBB2 isoform (ERBB2ΔEx16) that forms constitutively active homodimers. However, the broader implications of ERBB2 alternative splicing in human cancers have not been explored. Here, we have used genomic and transcriptomic analysis to identify elevated ERBB2ΔEx16 expression in a subset of NSCLC cases, as well as splicing site mutations facilitating exon 16 skipping and deletions of exon 16 in a subset of these lung tumors and in a number of other carcinomas. Supporting the potential of ERBB2ΔEx16 as a lung cancer driver, its expression transformed immortalized lung epithelial cells while a transgenic model featuring inducible ERBB2ΔEx16 specifically in the lung epithelium rapidly developed lung adenocarcinomas following transgene induction. Collectively, these observations indicate that ERBB2ΔEx16 is a lung cancer oncogene with potential clinical importance for a proportion of patients.


Assuntos
Carcinoma/genética , Predisposição Genética para Doença , Neoplasias Pulmonares/genética , Isoformas de Proteínas/genética , Receptor ErbB-2/metabolismo , Animais , Linhagem Celular Tumoral , Feminino , Humanos , Masculino , Camundongos , Ratos , Receptor ErbB-2/genética , Microambiente Tumoral
18.
Nat Commun ; 11(1): 3766, 2020 07 28.
Artigo em Inglês | MEDLINE | ID: mdl-32724076

RESUMO

Dipeptidyl peptidase-4 (DPP4) modulates inflammation by enzymatic cleavage of immunoregulatory peptides and through its soluble form (sDPP4) that directly engages immune cells. Here we examine whether reduction of DPP4 activity alters inflammation. Prolonged DPP4 inhibition increases plasma levels of sDPP4, and induces sDPP4 expression in lymphocyte-enriched organs in mice. Bone marrow transplantation experiments identify hematopoietic cells as the predominant source of plasma sDPP4 following catalytic DPP4 inhibition. Surprisingly, systemic DPP4 inhibition increases plasma levels of inflammatory markers in regular chow-fed but not in high fat-fed mice. Plasma levels of sDPP4 and biomarkers of inflammation are lower in metformin-treated subjects with type 2 diabetes (T2D) and cardiovascular disease, yet exhibit considerable inter-individual variation. Sitagliptin therapy for 12 months reduces DPP4 activity yet does not increase markers of inflammation or levels of sDPP4. Collectively our findings dissociate levels of DPP4 enzyme activity, sDPP4 and biomarkers of inflammation in mice and humans.


Assuntos
Doenças Cardiovasculares/imunologia , Diabetes Mellitus Tipo 2/tratamento farmacológico , Dipeptidil Peptidase 4/sangue , Inibidores da Dipeptidil Peptidase IV/efeitos adversos , Inflamação/imunologia , Idoso , Animais , Biomarcadores/análise , Biomarcadores/metabolismo , Doenças Cardiovasculares/sangue , Doenças Cardiovasculares/prevenção & controle , Diabetes Mellitus Tipo 2/sangue , Diabetes Mellitus Tipo 2/complicações , Diabetes Mellitus Tipo 2/imunologia , Dieta Aterogênica/efeitos adversos , Dieta Hiperlipídica/efeitos adversos , Dipeptidil Peptidase 4/imunologia , Dipeptidil Peptidase 4/metabolismo , Inibidores da Dipeptidil Peptidase IV/administração & dosagem , Modelos Animais de Doenças , Feminino , Receptor do Peptídeo Semelhante ao Glucagon 1/genética , Humanos , Inflamação/sangue , Inflamação/diagnóstico , Inflamação/tratamento farmacológico , Mediadores da Inflamação/análise , Mediadores da Inflamação/metabolismo , Masculino , Metformina/administração & dosagem , Camundongos , Camundongos Knockout , Pessoa de Meia-Idade , Isoformas de Proteínas/antagonistas & inibidores , Isoformas de Proteínas/sangue , Isoformas de Proteínas/metabolismo , Fosfato de Sitagliptina/administração & dosagem , Fosfato de Sitagliptina/efeitos adversos
19.
RNA ; 26(10): 1464-1480, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32631843

RESUMO

Many eukaryotes use RNA processing, including alternative splicing, to express multiple gene products from the same gene. The budding yeast Saccharomyces cerevisiae has been successfully used to study the mechanism of splicing and the splicing machinery, but alternative splicing in yeast is relatively rare and has not been extensively studied. Alternative splicing of SKI7/HBS1 is widely conserved, but yeast and a few other eukaryotes have replaced this one alternatively spliced gene with a pair of duplicated, unspliced genes as part of a whole genome doubling (WGD). We show that other examples of alternative splicing known to have functional consequences are widely conserved within Saccharomycotina. A common mechanism by which alternative splicing has disappeared is by replacement of an alternatively spliced gene with duplicate unspliced genes. This loss of alternative splicing does not always take place soon after duplication, but can take place after sufficient time has elapsed for speciation. Saccharomycetaceae that diverged before WGD use alternative splicing more frequently than S. cerevisiae, suggesting that WGD is a major reason for infrequent alternative splicing in yeast. We anticipate that WGDs in other lineages may have had the same effect. Having observed that two functionally distinct splice-isoforms are often replaced by duplicated genes allowed us to reverse the reasoning. We thereby identify several splice isoforms that are likely to produce two functionally distinct proteins because we find them replaced by duplicated genes in related species. We also identify some alternative splicing events that are not conserved in closely related species and unlikely to produce functionally distinct proteins.


Assuntos
Processamento Alternativo/genética , Proteoma/genética , Proteínas de Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/genética , Saccharomycetales/genética , Proteínas Adaptadoras de Transdução de Sinal/genética , Evolução Molecular , Duplicação Gênica/genética , Genoma/genética , Isoformas de Proteínas/genética
20.
Prostate ; 80(13): 1145-1156, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32659025

RESUMO

BACKGROUND: Epithelial stem cells (ESCs) demonstrate a capacity to maintain normal tissues homeostasis and ESCs with a deregulated behavior can contribute to cancer development. The ability to reprogram normal tissue epithelial cells into prostate or mammary stem-like cells holds great promise to help understand cell of origin and lineage plasticity in prostate and breast cancers in addition to understanding normal gland development. We previously showed that an intracellular chemokine, CXCL12γ induced cancer stem cells and neuroendocrine characteristics in both prostate and breast adenocarcinoma cell lines. However, its role in normal prostate or mammary epithelial cell fate and development remains unknown. Therefore, we sought to elucidate the functional role of CXCL12γ in the regulation of ESCs and tissue development. METHODS: Prostate epithelial cells (PNT2) or mammary epithelial cells (MCF10A) with overexpressed CXCL12γ was characterized by quantitative real-time polymerase chain reaction, Western blots, and immunofluorescence for lineage marker expression, and fluorescence activated cell sorting analyses and sphere formation assays to examine stem cell surface phenotype and function. Xenotransplantation animal models were used to evaluate gland or acini formation in vivo. RESULTS: Overexpression of CXCL12γ promotes the reprogramming of cells with a differentiated luminal phenotype to a nonluminal phenotype in both prostate (PNT2) and mammary (MCF10A) epithelial cells. The CXCL12γ-mediated nonluminal type cells results in an increase of epithelial stem-like phenotype including the subpopulation of EPCAMLo /CD49fHi /CD24Lo /CD44Hi cells capable of sphere formation. Critically, overexpression of CXCL12γ promotes the generation of robust gland-like structures from both prostate and mammary epithelial cells in in vivo xenograft animal models. CONCLUSIONS: CXCL12γ supports the reprogramming of epithelial cells into nonluminal cell-derived stem cells, which facilitates gland development.


Assuntos
Quimiocina CXCL12/biossíntese , Glândulas Mamárias Humanas/crescimento & desenvolvimento , Próstata/crescimento & desenvolvimento , Animais , Reprogramação Celular/fisiologia , Células Epiteliais/citologia , Células Epiteliais/metabolismo , Feminino , Xenoenxertos , Humanos , Masculino , Glândulas Mamárias Humanas/citologia , Glândulas Mamárias Humanas/metabolismo , Camundongos , Próstata/citologia , Próstata/metabolismo , Isoformas de Proteínas
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