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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.
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
3.
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
4.
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
5.
Proc Natl Acad Sci U S A ; 117(28): 16391-16400, 2020 07 14.
Artigo em Inglês | MEDLINE | ID: mdl-32601196

RESUMO

Master splicing regulator MBNL1 shapes large transcriptomic changes that drive cellular differentiation during development. Here we demonstrate that MBNL1 is a suppressor of tumor dedifferentiation. We surveyed MBNL1 expression in matched tumor/normal pairs across The Cancer Genome Atlas and found that MBNL1 was down-regulated in several common cancers. Down-regulation of MBNL1 predicted poor overall survival in breast, lung, and stomach adenocarcinomas and increased relapse and distant metastasis in triple-negative breast cancer. Down-regulation of MBNL1 led to increased tumorigenic and stem/progenitor-like properties in vitro and in vivo. A discrete set of alternative splicing events (ASEs) are shared between MBNL1-low cancers and embryonic stem cells including a MAP2K7∆exon2 splice variant that leads to increased stem/progenitor-like properties via JNK activation. Accordingly, JNK inhibition is capable of reversing MAP2K7∆exon2-driven tumor dedifferentiation in MBNL1-low cancer cells. Our work elucidates an alternative-splicing mechanism that drives tumor dedifferentiation and identifies biomarkers that predict enhanced susceptibility to JNK inhibition.


Assuntos
MAP Quinase Quinase 4/metabolismo , MAP Quinase Quinase 7/genética , MAP Quinase Quinase 7/metabolismo , Neoplasias/metabolismo , Proteínas de Ligação a RNA/metabolismo , Diferenciação Celular , Humanos , MAP Quinase Quinase 4/genética , Neoplasias/genética , Neoplasias/fisiopatologia , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Processamento de RNA , Proteínas de Ligação a RNA/genética
6.
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
7.
Mol Cell ; 79(3): 425-442.e7, 2020 08 06.
Artigo em Inglês | MEDLINE | ID: mdl-32615088

RESUMO

Double-strand breaks (DSBs) are the most deleterious DNA lesions, which, if left unrepaired, may lead to genome instability or cell death. Here, we report that, in response to DSBs, the RNA methyltransferase METTL3 is activated by ATM-mediated phosphorylation at S43. Phosphorylated METTL3 is then localized to DNA damage sites, where it methylates the N6 position of adenosine (m6A) in DNA damage-associated RNAs, which recruits the m6A reader protein YTHDC1 for protection. In this way, the METTL3-m6A-YTHDC1 axis modulates accumulation of DNA-RNA hybrids at DSBs sites, which then recruit RAD51 and BRCA1 for homologous recombination (HR)-mediated repair. METTL3-deficient cells display defective HR, accumulation of unrepaired DSBs, and genome instability. Accordingly, depletion of METTL3 significantly enhances the sensitivity of cancer cells and murine xenografts to DNA damage-based therapy. These findings uncover the function of METTL3 and YTHDC1 in HR-mediated DSB repair, which may have implications for cancer therapy.


Assuntos
Adenosina/análogos & derivados , Neoplasias de Cabeça e Pescoço/genética , Metiltransferases/genética , Proteínas do Tecido Nervoso/genética , Fatores de Processamento de RNA/genética , Reparo de DNA por Recombinação/efeitos dos fármacos , Carcinoma de Células Escamosas de Cabeça e Pescoço/genética , Adenosina/metabolismo , Animais , Antibióticos Antineoplásicos/farmacologia , Proteínas Mutadas de Ataxia Telangiectasia/genética , Proteínas Mutadas de Ataxia Telangiectasia/metabolismo , Proteína BRCA1/genética , Proteína BRCA1/metabolismo , Bleomicina/farmacologia , Linhagem Celular Tumoral , DNA/genética , DNA/metabolismo , Células Epiteliais/efeitos dos fármacos , Células Epiteliais/metabolismo , Células Epiteliais/patologia , Feminino , Células HEK293 , Neoplasias de Cabeça e Pescoço/tratamento farmacológico , Neoplasias de Cabeça e Pescoço/mortalidade , Neoplasias de Cabeça e Pescoço/patologia , Humanos , Metiltransferases/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Proteínas do Tecido Nervoso/metabolismo , Hibridização de Ácido Nucleico , Osteoblastos/efeitos dos fármacos , Osteoblastos/metabolismo , Osteoblastos/patologia , Fosforilação , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Fatores de Processamento de RNA/metabolismo , Rad51 Recombinase/genética , Rad51 Recombinase/metabolismo , Ribonuclease H/genética , Ribonuclease H/metabolismo , Carcinoma de Células Escamosas de Cabeça e Pescoço/tratamento farmacológico , Carcinoma de Células Escamosas de Cabeça e Pescoço/mortalidade , Carcinoma de Células Escamosas de Cabeça e Pescoço/patologia , Análise de Sobrevida , Ensaios Antitumorais Modelo de Xenoenxerto
8.
PLoS Genet ; 16(6): e1008829, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32502151

RESUMO

Ion channels are present at specific levels within subcellular compartments of excitable cells. The regulation of ion channel trafficking and targeting is an effective way to control cell excitability. The BK channel is a calcium-activated potassium channel that serves as a negative feedback mechanism at presynaptic axon terminals and sites of muscle excitation. The C. elegans BK channel ortholog, SLO-1, requires an endoplasmic reticulum (ER) membrane protein for efficient anterograde transport to these locations. Here, we found that, in the absence of this ER membrane protein, SLO-1 channels that are seemingly normally folded and expressed at physiological levels undergo SEL-11/HRD1-mediated ER-associated degradation (ERAD). This SLO-1 degradation is also indirectly regulated by a SKN-1A/NRF1-mediated transcriptional mechanism that controls proteasome levels. Therefore, our data indicate that SLO-1 channel density is regulated by the competitive balance between the efficiency of ER trafficking machinery and the capacity of ERAD.


Assuntos
Proteínas de Caenorhabditis elegans/metabolismo , Caenorhabditis elegans/fisiologia , Proteínas de Ligação a DNA/metabolismo , Degradação Associada com o Retículo Endoplasmático/genética , Canais de Potássio Ativados por Cálcio de Condutância Alta/metabolismo , Terminações Pré-Sinápticas/metabolismo , Fatores de Transcrição/metabolismo , Aldicarb/farmacologia , Animais , Animais Geneticamente Modificados , Caenorhabditis elegans/efeitos dos fármacos , Retículo Endoplasmático/metabolismo , Acoplamento Excitação-Contração/efeitos dos fármacos , Acoplamento Excitação-Contração/genética , Retroalimentação Fisiológica/efeitos dos fármacos , Proteínas de Membrana/metabolismo , Músculos/inervação , Terminações Pré-Sinápticas/efeitos dos fármacos , Complexo de Endopeptidases do Proteassoma , Isoformas de Proteínas/metabolismo , Ubiquitina-Proteína Ligases/metabolismo
9.
PLoS One ; 15(6): e0234147, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32479530

RESUMO

Conversion of cellular prion protein (PrPC) into the pathogenic isoform of prion protein (PrPSc) in neurons is one of the key pathophysiological events in prion diseases. However, the molecular mechanism of neurodegeneration in prion diseases has yet to be fully elucidated because of a lack of suitable experimental models for analyzing neuron-autonomous responses to prion infection. In the present study, we used neuron-enriched primary cultures of cortical and thalamic mouse neurons to analyze autonomous neuronal responses to prion infection. PrPSc levels in neurons increased over the time after prion infection; however, no obvious neuronal losses or neurite alterations were observed. Interestingly, a finer analysis of individual neurons co-stained with PrPSc and phosphorylated protein kinase RNA-activated-like endoplasmic reticulum (ER) kinase (p-PERK), the early cellular response of the PERK-eukaryotic initiation factor 2 (eIF2α) pathway, demonstrated a positive correlation between the number of PrPSc granular stains and p-PERK granular stains, in cortical neurons at 21 dpi. Although the phosphorylation of PERK was enhanced in prion-infected cortical neurons, there was no sign of subsequent translational repression of synaptic protein synthesis or activations of downstream unfolded protein response (UPR) in the PERK-eIF2α pathway. These results suggest that PrPSc production in neurons induces ER stress in a neuron-autonomous manner; however, it does not fully activate UPR in prion-infected neurons. Our findings provide insights into the autonomous neuronal responses to prion propagation and the involvement of neuron-non-autonomous factor(s) in the mechanisms of neurodegeneration in prion diseases.


Assuntos
Neurônios/metabolismo , Proteínas PrPSc/metabolismo , eIF-2 Quinase/metabolismo , Animais , Células Cultivadas , Estresse do Retículo Endoplasmático , Camundongos , Camundongos Endogâmicos ICR , Crescimento Neuronal , Neurônios/citologia , Fosforilação , Proteínas PrPSc/genética , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Resposta a Proteínas não Dobradas
10.
Proc Natl Acad Sci U S A ; 117(27): 15554-15564, 2020 07 07.
Artigo em Inglês | MEDLINE | ID: mdl-32561649

RESUMO

The serum haptoglobin protein (Hp) scavenges toxic hemoglobin (Hb) leaked into the bloodstream from erythrocytes. In humans, there are two frequently occurring allelic forms of Hp, resulting in three genotypes: Homozygous Hp 1-1 and Hp 2-2, and heterozygous Hp 2-1. The Hp genetic polymorphism has an intriguing effect on the quaternary structure of Hp. The simplest form, Hp 1-1, forms dimers consisting of two α1ß units, connected by disulfide bridges. Hp 2-1 forms mixtures of linear (α1)2(α2)n-2(ß)n oligomers (n > 1) while Hp 2-2 occurs in cyclic (α2)n(ß)n oligomers (n > 2). Different Hp genotypes bind Hb with different affinities, with Hp 2-2 being the weakest binder. This behavior has a significant influence on Hp's antioxidant capacity, with potentially distinctive personalized clinical consequences. Although Hp has been studied extensively in the past, the finest molecular details of the observed differences in interactions between Hp and Hb are not yet fully understood. Here, we determined the full proteoform profiles and proteoform assemblies of all three most common genetic Hp variants. We combined several state-of-the-art analytical methods, including various forms of chromatography, mass photometry, and different tiers of mass spectrometry, to reveal how the tens to hundreds distinct proteoforms and their assemblies influence Hp's capacity for Hb binding. We extend the current knowledge by showing that Hb binding does not just depend on the donor's genotype, but is also affected by variations in Hp oligomerization, glycosylation, and proteolytic processing of the Hp α-chain.


Assuntos
Haptoglobinas/genética , Hemoglobinas/metabolismo , Alelos , Antioxidantes/química , Antioxidantes/isolamento & purificação , Antioxidantes/metabolismo , Glicosilação , Haptoglobinas/química , Haptoglobinas/isolamento & purificação , Haptoglobinas/metabolismo , Hemoglobinas/toxicidade , Humanos , Espectrometria de Massas , Modelos Moleculares , Estrutura Molecular , Polimorfismo Genético , Ligação Proteica , Isoformas de Proteínas/química , Isoformas de Proteínas/genética , Isoformas de Proteínas/isolamento & purificação , Isoformas de Proteínas/metabolismo , Relação Estrutura-Atividade
11.
Arch Biochem Biophys ; 689: 108443, 2020 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-32485152

RESUMO

Human peroxidasin 1 (PXDN) is a homotrimeric multidomain heme peroxidase and essential for tissue development and architecture. It has a biosynthetic function and catalyses the hypobromous acid-mediated formation of specific covalent sulfilimine (SN) bonds, which cross-link type IV collagen chains in basement membranes. Currently, it is unknown whether and which domain(s) [i.e. leucine-rich repeat domain (LRR), immunoglobulin domains, peroxidase domain, von Willebrand factor type C domain] of PXDN interact with the polymeric networks of the extracellular matrix (ECM), and how these interactions integrate and regulate the enzyme's cross-linking activity, without imparting oxidative damage to the ECM. In this study, we probed the interactions of four PXDN constructs with different domain compositions with components of a basement membrane extract by immunoprecipitation. Strong binding of the LRR-containing construct was detected with the major ECM protein laminin. Analysis of these interactions by surface plasmon resonance spectroscopy revealed similar kinetics and affinities of binding of the LRR-containing construct to human and murine laminin-111, with calculated dissociation constants of 1.0 and 1.5 µM, respectively. The findings are discussed with respect to the recently published in-solution structures of the PXDN constructs and the proposed biological role of this peroxidase.


Assuntos
Membrana Basal/metabolismo , Laminina/metabolismo , Peroxidases/metabolismo , Animais , Células HEK293 , Humanos , Leucina/química , Leucina/metabolismo , Camundongos , Peroxidases/química , Ligação Proteica , Domínios Proteicos , Isoformas de Proteínas/metabolismo
12.
Int J Mol Sci ; 21(10)2020 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-32429235

RESUMO

We live and to do so we must breathe and eat, so are we a combination of what we eat and breathe? Here, we will consider this question, and the role in this respect of the AMP-activated protein kinase (AMPK). Emerging evidence suggests that AMPK facilitates central and peripheral reflexes that coordinate breathing and oxygen supply, and contributes to the central regulation of feeding and food choice. We propose, therefore, that oxygen supply to the body is aligned with not only the quantity we eat, but also nutrient-based diet selection, and that the cell-specific expression pattern of AMPK subunit isoforms is critical to appropriate system alignment in this respect. Currently available information on how oxygen supply may be aligned with feeding and food choice, or vice versa, through our motivation to breathe and select particular nutrients is sparse, fragmented and lacks any integrated understanding. By addressing this, we aim to provide the foundations for a clinical perspective that reveals untapped potential, by highlighting how aberrant cell-specific changes in the expression of AMPK subunit isoforms could give rise, in part, to known associations between metabolic disease, such as obesity and type 2 diabetes, sleep-disordered breathing, pulmonary hypertension and acute respiratory distress syndrome.


Assuntos
Proteínas Quinases Ativadas por AMP/metabolismo , Oxigênio/metabolismo , Proteínas Quinases Ativadas por AMP/genética , Animais , Dieta , Humanos , Doenças Metabólicas/metabolismo , Doenças Metabólicas/patologia , Isoformas de Proteínas/metabolismo , Respiração , Transtornos Respiratórios/metabolismo , Transtornos Respiratórios/patologia , Termogênese
13.
Nat Commun ; 11(1): 2444, 2020 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-32415068

RESUMO

The essential role of ORAI1 channels in receptor-evoked Ca2+ signaling is well understood, yet little is known about the physiological activation of the ORAI channel trio natively expressed in all cells. The roles of ORAI2 and ORAI3 have remained obscure. We show that ORAI2 and ORAI3 channels play a critical role in mediating the regenerative Ca2+ oscillations induced by physiological receptor activation, yet ORAI1 is dispensable in generation of oscillations. We reveal that ORAI2 and ORAI3 channels multimerize with ORAI1 to expand the range of sensitivity of receptor-activated Ca2+ signals, reflecting their enhanced basal STIM1-binding and heightened Ca2+-dependent inactivation. This broadened bandwidth of Ca2+ influx is translated by cells into differential activation of NFAT1 and NFAT4 isoforms. Our results uncover a long-sought role for ORAI2 and ORAI3, revealing an intricate control mechanism whereby heteromerization of ORAI channels mediates graded Ca2+ signals that extend the agonist-sensitivity to fine-tune transcriptional control.


Assuntos
Canais de Cálcio Ativados pela Liberação de Cálcio/metabolismo , Sinalização do Cálcio , Cálcio/metabolismo , Canais de Cálcio/metabolismo , Sinalização do Cálcio/efeitos dos fármacos , Carbacol/farmacologia , Retículo Endoplasmático/efeitos dos fármacos , Retículo Endoplasmático/metabolismo , Células HEK293 , Humanos , Modelos Biológicos , Fatores de Transcrição NFATC/metabolismo , Proteína ORAI1/metabolismo , Ligação Proteica/efeitos dos fármacos , Isoformas de Proteínas/metabolismo , Multimerização Proteica/efeitos dos fármacos , Molécula 1 de Interação Estromal/metabolismo , Imagem com Lapso de Tempo
14.
Nat Commun ; 11(1): 2326, 2020 05 11.
Artigo em Inglês | MEDLINE | ID: mdl-32393825

RESUMO

Most human protein-coding genes are expressed as multiple isoforms, which greatly expands the functional repertoire of the encoded proteome. While at least one reliable open reading frame (ORF) model has been assigned for every coding gene, the majority of alternative isoforms remains uncharacterized due to (i) vast differences of overall levels between different isoforms expressed from common genes, and (ii) the difficulty of obtaining full-length transcript sequences. Here, we present ORF Capture-Seq (OCS), a flexible method that addresses both challenges for targeted full-length isoform sequencing applications using collections of cloned ORFs as probes. As a proof-of-concept, we show that an OCS pipeline focused on genes coding for transcription factors increases isoform detection by an order of magnitude when compared to unenriched samples. In short, OCS enables rapid discovery of isoforms from custom-selected genes and will accelerate mapping of the human transcriptome.


Assuntos
Fases de Leitura Aberta/genética , Análise de Sequência de RNA/métodos , Humanos , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Padrões de Referência , Fatores de Transcrição/genética
15.
Nat Commun ; 11(1): 2066, 2020 04 29.
Artigo em Inglês | MEDLINE | ID: mdl-32350269

RESUMO

Mutations in myosin-VIIa (MYO7A) cause Usher syndrome type 1, characterized by combined deafness and blindness. MYO7A is proposed to function as a motor that tensions the hair cell mechanotransduction (MET) complex, but conclusive evidence is lacking. Here we report that multiple MYO7A isoforms are expressed in the mouse cochlea. In mice with a specific deletion of the canonical isoform (Myo7a-ΔC mouse), MYO7A is severely diminished in inner hair cells (IHCs), while expression in outer hair cells is affected tonotopically. IHCs of Myo7a-ΔC mice undergo normal development, but exhibit reduced resting open probability and slowed onset of MET currents, consistent with MYO7A's proposed role in tensioning the tip link. Mature IHCs of Myo7a-ΔC mice degenerate over time, giving rise to progressive hearing loss. Taken together, our study reveals an unexpected isoform diversity of MYO7A expression in the cochlea and highlights MYO7A's essential role in tensioning the hair cell MET complex.


Assuntos
Células Ciliadas Auditivas Internas/metabolismo , Mecanotransdução Celular , Miosina VIIa/metabolismo , Sequência de Aminoácidos , Animais , Sequência de Bases , Proteínas de Ciclo Celular/metabolismo , Proteínas do Citoesqueleto/metabolismo , Deleção de Genes , Células Ciliadas Auditivas Internas/ultraestrutura , Perda Auditiva/metabolismo , Perda Auditiva/patologia , Camundongos Endogâmicos C57BL , Miosina VIIa/química , Miosina VIIa/genética , Isoformas de Proteínas/metabolismo , Transporte Proteico , Estereocílios/metabolismo , Estereocílios/ultraestrutura
16.
Nat Commun ; 11(1): 2395, 2020 05 14.
Artigo em Inglês | MEDLINE | ID: mdl-32409656

RESUMO

Pollen tubes are highly polarized tip-growing cells that depend on cytosolic pH gradients for signaling and growth. Autoinhibited plasma membrane proton (H+) ATPases (AHAs) have been proposed to energize pollen tube growth and underlie cell polarity, however, mechanistic evidence for this is lacking. Here we report that the combined loss of AHA6, AHA8, and AHA9 in Arabidopsis thaliana delays pollen germination and causes pollen tube growth defects, leading to drastically reduced fertility. Pollen tubes of aha mutants had reduced extracellular proton (H+) and anion fluxes, reduced cytosolic pH, reduced tip-to-shank proton gradients, and defects in actin organization. Furthermore, mutant pollen tubes had less negative membrane potentials, substantiating a mechanistic role for AHAs in pollen tube growth through plasma membrane hyperpolarization. Our findings define AHAs as energy transducers that sustain the ionic circuit defining the spatial and temporal profiles of cytosolic pH, thereby controlling downstream pH-dependent mechanisms essential for pollen tube elongation, and thus plant fertility.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/fisiologia , Tubo Polínico/crescimento & desenvolvimento , Polinização/fisiologia , ATPases Translocadoras de Prótons/metabolismo , Proteínas de Arabidopsis/genética , Membrana Celular/metabolismo , Polaridade Celular/fisiologia , Citosol/metabolismo , Técnicas de Silenciamento de Genes , Germinação/fisiologia , Concentração de Íons de Hidrogênio , Potenciais da Membrana/fisiologia , Mutação , Plantas Geneticamente Modificadas , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , ATPases Translocadoras de Prótons/genética , Análise Espaço-Temporal
17.
Mol Cell ; 78(6): 1114-1132.e10, 2020 06 18.
Artigo em Inglês | MEDLINE | ID: mdl-32446320

RESUMO

Bromodomain-containing protein 4 (BRD4) is a cancer therapeutic target in ongoing clinical trials disrupting primarily BRD4-regulated transcription programs. The role of BRD4 in cancer has been attributed mainly to the abundant long isoform (BRD4-L). Here we show, by isoform-specific knockdown and endogenous protein detection, along with transgene expression, the less abundant BRD4 short isoform (BRD4-S) is oncogenic while BRD4-L is tumor-suppressive in breast cancer cell proliferation and migration, as well as mammary tumor formation and metastasis. Through integrated RNA-seq, genome-wide ChIP-seq, and CUT&RUN association profiling, we identify the Engrailed-1 (EN1) homeobox transcription factor as a key BRD4-S coregulator, particularly in triple-negative breast cancer. BRD4-S and EN1 comodulate the extracellular matrix (ECM)-associated matrisome network, including type II cystatin gene cluster, mucin 5, and cathepsin loci, via enhancer regulation of cancer-associated genes and pathways. Our work highlights the importance of targeted therapies for the oncogenic, but not tumor-suppressive, activity of BRD4.


Assuntos
Neoplasias da Mama/metabolismo , Proteínas de Ciclo Celular/metabolismo , Proteínas de Ciclo Celular/fisiologia , Fatores de Transcrição/metabolismo , Fatores de Transcrição/fisiologia , Animais , Neoplasias da Mama/genética , Linhagem Celular Tumoral , Movimento Celular , Proliferação de Células , Feminino , Regulação Neoplásica da Expressão Gênica/genética , Genes Homeobox , Proteínas de Homeodomínio/metabolismo , Humanos , Camundongos , Invasividade Neoplásica , Proteínas Nucleares/metabolismo , Isoformas de Proteínas/metabolismo , Proteínas/antagonistas & inibidores , Proteínas/metabolismo , Transcrição Genética/genética , Neoplasias de Mama Triplo Negativas/genética
18.
Gene ; 747: 144673, 2020 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-32304783

RESUMO

Krabbe disease is one of the rarest autosomal recessive disorders in human, caused by mutation in the GALC (ß-galactosylceramidase) gene, resulting in several mental and physical health issues. Due to its rarity and phenotypic heterogeneity, diagnosis rate of this disease is very low. This study generated information on the recessive allele frequency dynamics of GALC gene across 15 global populations, with the highest frequency detected in Druze (Israel) population and the lowest frequency in Turkey and the United States. The recessive allele would take more time period (about 24,975 years) to be completely removed from the population having the lowest frequency and vice versa. The codon usage patterns of four isoforms of GALC gene revealed that a few synonymous codons were used more frequently than others in the isoforms. The codon AGA (arginine) was found to be overrepresented in GALC gene, except for galactocerebrosidase isoform a precursor. Further, GALC gene showed low codon usage bias (CUB) as evident from high ENC values (55.7-58.2), with A/T ending codons more preferred to G/C ending codons. CUB analysis elucidated the dual role of mutational pressure (major role) and natural selection (minor role) in GALC gene evolution.


Assuntos
Uso do Códon/genética , Galactosilceramidase/genética , Frequência do Gene/genética , Leucodistrofia de Células Globoides/enzimologia , Leucodistrofia de Células Globoides/genética , Aminoácidos/genética , Composição de Bases/genética , Códon/genética , Evolução Molecular , Galactosilceramidase/metabolismo , Humanos , Filogenia , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo
19.
Food Chem ; 321: 126677, 2020 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-32247180

RESUMO

Myosin heavy chain (MHC) isoforms in goat muscles and their possible relationships with meat quality have not been fully elucidated. This study characterized the MHC isoforms in different caprine muscles using sodium dodecyl sulphate glycerol gel electrophoresis (SDS-GGE). The relationships between MHC isoforms, calpain systems and meat quality characteristics of different muscles in goats were examined. Four muscles, namely infraspinatus (IF), longissimus dorsi (LD), psoas major (PM) and supraspinatus (SS) were obtained from ten Boer crossbred bucks (7-10 months old; 26.5 ± 3.5 kg, BW). The percentages of MHC I, MHC IIa and MHC IIx in SS, IF, PM and LD were 47.2, 38.3, 32.1, 11.9; 28.0, 42.1, 33.0, 36.4; and 24.8, 19.6, 34.9 and 51.7, respectively. IF and SS had higher levels of calpastatin, total collagen and insoluble collagen contents than did PM and LD. PM had longer sarcomere length than did other muscles. LD had higher collagen solubility, troponin-T degradation products and glycogen content than did other muscles. These results infer that variable fiber-type composition could account partially for the differences in the physicochemical properties of goat muscles.


Assuntos
Calpaína/metabolismo , Músculo Esquelético/metabolismo , Cadeias Pesadas de Miosina/metabolismo , Animais , Proteínas de Ligação ao Cálcio/metabolismo , Eletroforese , Eletroforese em Gel de Poliacrilamida , Cabras , Carne/análise , Músculo Esquelético/química , Isoformas de Proteínas/metabolismo , Troponina T/metabolismo
20.
PLoS Genet ; 16(4): e1008721, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32339198

RESUMO

Current estimates suggest 50% of glaucoma blindness worldwide is caused by primary angle-closure glaucoma (PACG) but the causative gene is not known. We used genetic linkage and whole genome sequencing to identify Spermatogenesis Associated Protein 13, SPATA13 (NM_001166271; NP_001159743, SPATA13 isoform I), also known as ASEF2 (Adenomatous polyposis coli-stimulated guanine nucleotide exchange factor 2), as the causal gene for PACG in a large seven-generation white British family showing variable expression and incomplete penetrance. The 9 bp deletion, c.1432_1440del; p.478_480del was present in all affected individuals with angle-closure disease. We show ubiquitous expression of this transcript in cell lines derived from human tissues and in iris, retina, retinal pigment and ciliary epithelia, cornea and lens. We also identified eight additional mutations in SPATA13 in a cohort of 189 unrelated PACS/PAC/PACG samples. This gene encodes a 1277 residue protein which localises to the nucleus with partial co-localisation with nuclear speckles. In cells undergoing mitosis SPATA13 isoform I becomes part of the kinetochore complex co-localising with two kinetochore markers, polo like kinase 1 (PLK-1) and centrosome-associated protein E (CENP-E). The 9 bp deletion reported in this study increases the RAC1-dependent guanine nucleotide exchange factors (GEF) activity. The increase in GEF activity was also observed in three other variants identified in this study. Taken together, our data suggest that SPATA13 is involved in the regulation of mitosis and the mutations dysregulate GEF activity affecting homeostasis in tissues where it is highly expressed, influencing PACG pathogenesis.


Assuntos
Glaucoma de Ângulo Aberto/genética , Fatores de Troca do Nucleotídeo Guanina/genética , Mutação , Adolescente , Adulto , Idoso , Divisão Celular , Núcleo Celular/metabolismo , Olho/metabolismo , Feminino , Glaucoma de Ângulo Aberto/patologia , Fatores de Troca do Nucleotídeo Guanina/química , Fatores de Troca do Nucleotídeo Guanina/metabolismo , Humanos , Cinetocoros/metabolismo , Masculino , Pessoa de Meia-Idade , Linhagem , Isoformas de Proteínas/química , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Transporte Proteico
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