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1.
Cell ; 187(3): 517-520, 2024 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-38306978

RESUMO

Structural biology, as powerful as it is, can be misleading. We highlight four fundamental challenges: interpreting raw experimental data; accounting for motion; addressing the misleading nature of in vitro structures; and unraveling interactions between drugs and "anti-targets." Overcoming these challenges will amplify the impact of structural biology on drug discovery.


Assuntos
Descoberta de Drogas , Biologia Molecular , Beleza
2.
Cell ; 186(4): 864-876.e21, 2023 02 16.
Artigo em Inglês | MEDLINE | ID: mdl-36750095

RESUMO

A fundamental strategy of eukaryotic antiviral immunity involves the cGAS enzyme, which synthesizes 2',3'-cGAMP and activates the effector STING. Diverse bacteria contain cGAS-like enzymes that produce cyclic oligonucleotides and induce anti-phage activity, known as CBASS. However, this activity has only been demonstrated through heterologous expression. Whether bacteria harboring CBASS antagonize and co-evolve with phages is unknown. Here, we identified an endogenous cGAS-like enzyme in Pseudomonas aeruginosa that generates 3',3'-cGAMP during phage infection, signals to a phospholipase effector, and limits phage replication. In response, phages express an anti-CBASS protein ("Acb2") that forms a hexamer with three 3',3'-cGAMP molecules and reduces phospholipase activity. Acb2 also binds to molecules produced by other bacterial cGAS-like enzymes (3',3'-cUU/UA/UG/AA) and mammalian cGAS (2',3'-cGAMP), suggesting broad inhibition of cGAS-based immunity. Upon Acb2 deletion, CBASS blocks lytic phage replication and lysogenic induction, but rare phages evade CBASS through major capsid gene mutations. Altogether, we demonstrate endogenous CBASS anti-phage function and strategies of CBASS inhibition and evasion.


Assuntos
Bactérias , Bacteriófagos , Animais , Bactérias/imunologia , Bactérias/virologia , Bacteriófagos/fisiologia , Imunidade , Nucleotidiltransferases/metabolismo
3.
Cell ; 180(3): 568-584.e23, 2020 02 06.
Artigo em Inglês | MEDLINE | ID: mdl-31981491

RESUMO

We present the largest exome sequencing study of autism spectrum disorder (ASD) to date (n = 35,584 total samples, 11,986 with ASD). Using an enhanced analytical framework to integrate de novo and case-control rare variation, we identify 102 risk genes at a false discovery rate of 0.1 or less. Of these genes, 49 show higher frequencies of disruptive de novo variants in individuals ascertained to have severe neurodevelopmental delay, whereas 53 show higher frequencies in individuals ascertained to have ASD; comparing ASD cases with mutations in these groups reveals phenotypic differences. Expressed early in brain development, most risk genes have roles in regulation of gene expression or neuronal communication (i.e., mutations effect neurodevelopmental and neurophysiological changes), and 13 fall within loci recurrently hit by copy number variants. In cells from the human cortex, expression of risk genes is enriched in excitatory and inhibitory neuronal lineages, consistent with multiple paths to an excitatory-inhibitory imbalance underlying ASD.


Assuntos
Transtorno Autístico/genética , Córtex Cerebral/crescimento & desenvolvimento , Sequenciamento do Exoma/métodos , Regulação da Expressão Gênica no Desenvolvimento , Neurobiologia/métodos , Estudos de Casos e Controles , Linhagem da Célula , Estudos de Coortes , Exoma , Feminino , Frequência do Gene , Predisposição Genética para Doença , Humanos , Masculino , Mutação de Sentido Incorreto , Neurônios/metabolismo , Fenótipo , Fatores Sexuais , Análise de Célula Única/métodos
4.
Cell ; 182(5): 1198-1213.e14, 2020 09 03.
Artigo em Inglês | MEDLINE | ID: mdl-32888493

RESUMO

Most loci identified by GWASs have been found in populations of European ancestry (EUR). In trans-ethnic meta-analyses for 15 hematological traits in 746,667 participants, including 184,535 non-EUR individuals, we identified 5,552 trait-variant associations at p < 5 × 10-9, including 71 novel associations not found in EUR populations. We also identified 28 additional novel variants in ancestry-specific, non-EUR meta-analyses, including an IL7 missense variant in South Asians associated with lymphocyte count in vivo and IL-7 secretion levels in vitro. Fine-mapping prioritized variants annotated as functional and generated 95% credible sets that were 30% smaller when using the trans-ethnic as opposed to the EUR-only results. We explored the clinical significance and predictive value of trans-ethnic variants in multiple populations and compared genetic architecture and the effect of natural selection on these blood phenotypes between populations. Altogether, our results for hematological traits highlight the value of a more global representation of populations in genetic studies.


Assuntos
Povo Asiático/genética , Mutação de Sentido Incorreto/genética , Polimorfismo de Nucleotídeo Único/genética , População Branca/genética , Genética , Estudo de Associação Genômica Ampla/métodos , Células HEK293 , Humanos , Interleucina-7/genética , Fenótipo
5.
Cell ; 182(5): 1214-1231.e11, 2020 09 03.
Artigo em Inglês | MEDLINE | ID: mdl-32888494

RESUMO

Blood cells play essential roles in human health, underpinning physiological processes such as immunity, oxygen transport, and clotting, which when perturbed cause a significant global health burden. Here we integrate data from UK Biobank and a large-scale international collaborative effort, including data for 563,085 European ancestry participants, and discover 5,106 new genetic variants independently associated with 29 blood cell phenotypes covering a range of variation impacting hematopoiesis. We holistically characterize the genetic architecture of hematopoiesis, assess the relevance of the omnigenic model to blood cell phenotypes, delineate relevant hematopoietic cell states influenced by regulatory genetic variants and gene networks, identify novel splice-altering variants mediating the associations, and assess the polygenic prediction potential for blood traits and clinical disorders at the interface of complex and Mendelian genetics. These results show the power of large-scale blood cell trait GWAS to interrogate clinically meaningful variants across a wide allelic spectrum of human variation.


Assuntos
Predisposição Genética para Doença/genética , Herança Multifatorial/genética , Feminino , Redes Reguladoras de Genes/genética , Estudo de Associação Genômica Ampla/métodos , Hematopoese/genética , Humanos , Masculino , Fenótipo , Polimorfismo de Nucleotídeo Único/genética
6.
Nat Immunol ; 21(7): 790-801, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32424361

RESUMO

Plasmodium parasite-specific antibodies are critical for protection against malaria, yet the development of long-lived and effective humoral immunity against Plasmodium takes many years and multiple rounds of infection and cure. Here, we report that the rapid development of short-lived plasmablasts during experimental malaria unexpectedly hindered parasite control by impeding germinal center responses. Metabolic hyperactivity of plasmablasts resulted in nutrient deprivation of the germinal center reaction, limiting the generation of memory B cell and long-lived plasma cell responses. Therapeutic administration of a single amino acid to experimentally infected mice was sufficient to overcome the metabolic constraints imposed by plasmablasts and enhanced parasite clearance and the formation of protective humoral immune memory responses. Thus, our studies not only challenge the current model describing the role and function of blood-stage Plasmodium-induced plasmablasts but they also reveal new targets and strategies to improve anti-Plasmodium humoral immunity.


Assuntos
Imunidade Humoral , Malária/imunologia , Plasmócitos/metabolismo , Plasmodium falciparum/imunologia , Adolescente , Adulto , Aminoácidos/administração & dosagem , Aminoácidos/metabolismo , Animais , Anticorpos Antiprotozoários/sangue , Anticorpos Antiprotozoários/imunologia , Anticorpos Antiprotozoários/metabolismo , Antimaláricos/administração & dosagem , DNA de Protozoário/isolamento & purificação , Modelos Animais de Doenças , Centro Germinativo/citologia , Centro Germinativo/imunologia , Centro Germinativo/metabolismo , Interações Hospedeiro-Parasita/imunologia , Humanos , Malária/sangue , Malária/tratamento farmacológico , Malária/parasitologia , Camundongos , Camundongos Transgênicos , Pessoa de Meia-Idade , Nutrientes/metabolismo , Plasmócitos/imunologia , Plasmócitos/parasitologia , Plasmodium falciparum/genética , Plasmodium falciparum/isolamento & purificação , Estudo de Prova de Conceito , Adulto Jovem
7.
Immunity ; 55(10): 1891-1908.e12, 2022 10 11.
Artigo em Inglês | MEDLINE | ID: mdl-36044899

RESUMO

Demodex mites are commensal parasites of hair follicles (HFs). Normally asymptomatic, inflammatory outgrowth of mites can accompany malnutrition, immune dysfunction, and aging, but mechanisms restricting Demodex outgrowth are not defined. Here, we show that control of mite HF colonization in mice required group 2 innate lymphoid cells (ILC2s), interleukin-13 (IL-13), and its receptor, IL-4Ra-IL-13Ra1. HF-associated ILC2s elaborated IL-13 that attenuated HFs and epithelial proliferation at anagen onset; in their absence, Demodex colonization led to increased epithelial proliferation and replacement of gene programs for repair by aberrant inflammation, leading to the loss of barrier function and HF exhaustion. Humans with rhinophymatous acne rosacea, an inflammatory condition associated with Demodex, had increased HF inflammation with decreased type 2 cytokines, consistent with the inverse relationship seen in mice. Our studies uncover a key role for skin ILC2s and IL-13, which comprise an immune checkpoint that sustains cutaneous integrity and restricts pathologic infestation by colonizing HF mites.


Assuntos
Infestações por Ácaros , Ácaros , Animais , Citocinas , Folículo Piloso/patologia , Humanos , Imunidade Inata , Inflamação , Interleucina-13 , Linfócitos/patologia , Camundongos , Infestações por Ácaros/complicações , Infestações por Ácaros/parasitologia , Infestações por Ácaros/patologia , Simbiose
8.
Cell ; 167(2): 369-381.e12, 2016 Oct 06.
Artigo em Inglês | MEDLINE | ID: mdl-27693355

RESUMO

Prions are a paradigm-shifting mechanism of inheritance in which phenotypes are encoded by self-templating protein conformations rather than nucleic acids. Here, we examine the breadth of protein-based inheritance across the yeast proteome by assessing the ability of nearly every open reading frame (ORF; ∼5,300 ORFs) to induce heritable traits. Transient overexpression of nearly 50 proteins created traits that remained heritable long after their expression returned to normal. These traits were beneficial, had prion-like patterns of inheritance, were common in wild yeasts, and could be transmitted to naive cells with protein alone. Most inducing proteins were not known prions and did not form amyloid. Instead, they are highly enriched in nucleic acid binding proteins with large intrinsically disordered domains that have been widely conserved across evolution. Thus, our data establish a common type of protein-based inheritance through which intrinsically disordered proteins can drive the emergence of new traits and adaptive opportunities.


Assuntos
Proteínas Intrinsicamente Desordenadas/metabolismo , Característica Quantitativa Herdável , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/genética , Amiloide/metabolismo , Evolução Molecular , Proteínas de Choque Térmico HSP70/genética , Proteínas de Choque Térmico HSP70/metabolismo , Proteínas de Choque Térmico HSP90/genética , Proteínas de Choque Térmico HSP90/metabolismo , Proteínas de Choque Térmico/genética , Proteínas de Choque Térmico/metabolismo , Proteínas Intrinsicamente Desordenadas/química , Proteínas Intrinsicamente Desordenadas/genética , Fases de Leitura Aberta , Príons/química , Príons/metabolismo , Proteoma , Proteínas de Saccharomyces cerevisiae/química , Proteínas de Saccharomyces cerevisiae/genética
9.
Cell ; 166(4): 1004-1015, 2016 Aug 11.
Artigo em Inglês | MEDLINE | ID: mdl-27453467

RESUMO

Targeted HIV cure strategies require definition of the mechanisms that maintain the virus. Here, we tracked HIV replication and the persistence of infected CD4 T cells in individuals with natural virologic control by sequencing viruses, T cell receptor genes, HIV integration sites, and cellular transcriptomes. Our results revealed three mechanisms of HIV persistence operating within distinct anatomic and functional compartments. In lymph node, we detected viruses with genetic and transcriptional attributes of active replication in both T follicular helper (TFH) cells and non-TFH memory cells. In blood, we detected inducible proviruses of archival origin among highly differentiated, clonally expanded cells. Linking the lymph node and blood was a small population of circulating cells harboring inducible proviruses of recent origin. Thus, HIV replication in lymphoid tissue, clonal expansion of infected cells, and recirculation of recently infected cells act together to maintain the virus in HIV controllers despite effective antiviral immunity.


Assuntos
Infecções por HIV/virologia , HIV-1/fisiologia , Sangue/virologia , Linfócitos T CD4-Positivos/imunologia , Doença Crônica , DNA Viral/genética , Infecções por HIV/imunologia , HIV-1/genética , Humanos , Leucócitos Mononucleares , Linfonodos/virologia , Provírus/imunologia , Análise de Sequência de DNA , Fenômenos Fisiológicos Virais , Replicação Viral
10.
Nature ; 629(8010): 80-85, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38693414

RESUMO

Building a fault-tolerant quantum computer will require vast numbers of physical qubits. For qubit technologies based on solid-state electronic devices1-3, integrating millions of qubits in a single processor will require device fabrication to reach a scale comparable to that of the modern complementary metal-oxide-semiconductor (CMOS) industry. Equally important, the scale of cryogenic device testing must keep pace to enable efficient device screening and to improve statistical metrics such as qubit yield and voltage variation. Spin qubits1,4,5 based on electrons in Si have shown impressive control fidelities6-9 but have historically been challenged by yield and process variation10-12. Here we present a testing process using a cryogenic 300-mm wafer prober13 to collect high-volume data on the performance of hundreds of industry-manufactured spin qubit devices at 1.6 K. This testing method provides fast feedback to enable optimization of the CMOS-compatible fabrication process, leading to high yield and low process variation. Using this system, we automate measurements of the operating point of spin qubits and investigate the transitions of single electrons across full wafers. We analyse the random variation in single-electron operating voltages and find that the optimized fabrication process leads to low levels of disorder at the 300-mm scale. Together, these results demonstrate the advances that can be achieved through the application of CMOS-industry techniques to the fabrication and measurement of spin qubit devices.

11.
Nat Immunol ; 18(4): 456-463, 2017 04.
Artigo em Inglês | MEDLINE | ID: mdl-28192417

RESUMO

Immunodominance (ID) defines the hierarchical immune response to competing antigens in complex immunogens. Little is known regarding B cell and antibody ID despite its importance in immunity to viruses and other pathogens. We show that B cells and serum antibodies from inbred mice demonstrate a reproducible ID hierarchy to the five major antigenic sites in the influenza A virus hemagglutinin globular domain. The hierarchy changed as the immune response progressed, and it was dependent on antigen formulation and delivery. Passive antibody transfer and sequential infection experiments demonstrated 'original antigenic suppression', a phenomenon in which antibodies suppress memory responses to the priming antigenic site. Our study provides a template for attaining deeper understanding of antibody ID to viruses and other complex immunogens.


Assuntos
Linfócitos B/imunologia , Linfócitos B/metabolismo , Interações Hospedeiro-Patógeno/imunologia , Epitopos Imunodominantes/imunologia , Viroses/imunologia , Vírus/imunologia , Animais , Anticorpos Antivirais/sangue , Anticorpos Antivirais/imunologia , Antígenos Virais/química , Antígenos Virais/imunologia , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD4-Positivos/metabolismo , Patrimônio Genético , Glicoproteínas de Hemaglutininação de Vírus da Influenza/química , Glicoproteínas de Hemaglutininação de Vírus da Influenza/imunologia , Interações Hospedeiro-Patógeno/genética , Imunização , Epitopos Imunodominantes/química , Memória Imunológica , Vírus da Influenza A/imunologia , Linfonodos/imunologia , Camundongos , Modelos Moleculares , Infecções por Orthomyxoviridae/genética , Infecções por Orthomyxoviridae/imunologia , Conformação Proteica , Viroses/genética , Viroses/virologia
12.
Immunity ; 53(4): 805-823.e15, 2020 10 13.
Artigo em Inglês | MEDLINE | ID: mdl-33053330

RESUMO

The activating receptor CD226 is expressed on lymphocytes, monocytes, and platelets and promotes anti-tumor immunity in pre-clinical models. Here, we examined the role of CD226 in the function of tumor-infiltrating lymphocytes (TILs) and resistance to immunotherapy. In murine tumors, a large proportion of CD8+ TILs had decreased surface expression of CD226 and exhibited features of dysfunction, whereas CD226hi TILs were highly functional. This correlation was seen also in TILs isolated from HNSCC patients. Mutation of CD226 at tyrosine 319 (Y319) led to increased CD226 surface expression, enhanced anti-tumor immunity and improved efficacy of immune checkpoint blockade (ICB). Mechanistically, tumor-derived CD155, the ligand for CD226, initiated phosphorylation of Y319 by Src kinases, thereby enabling ubiquitination of CD226 by CBL-B, internalization, and proteasomal degradation. In pre-treatment samples from melanoma patients, CD226+CD8+ T cells correlated with improved progression-free survival following ICB. Our findings argue for the development of therapies aimed at maintaining the expression of CD226.


Assuntos
Antígenos de Diferenciação de Linfócitos T/imunologia , Linfócitos T CD8-Positivos/imunologia , Receptores Virais/imunologia , Animais , Linhagem Celular , Linhagem Celular Tumoral , Células HEK293 , Humanos , Inibidores de Checkpoint Imunológico/imunologia , Imunoterapia/métodos , Células Jurkat , Linfócitos do Interstício Tumoral/imunologia , Masculino , Melanoma/imunologia , Camundongos , Camundongos Endogâmicos C57BL
13.
Nature ; 619(7971): 716-719, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-37216978

RESUMO

The extremely rapid assembly of the earliest galaxies during the first billion years of cosmic history is a major challenge for our understanding of galaxy formation physics1-5. The advent of the James Webb Space Telescope (JWST) has exacerbated this issue by confirming the existence of galaxies in substantial numbers as early as the first few hundred million years6-8. Perhaps even more surprisingly, in some galaxies, this initial highly efficient star formation rapidly shuts down, or quenches, giving rise to massive quiescent galaxies as little as 1.5 billion years after the Big Bang9,10. However, due to their faintness and red colour, it has proven extremely challenging to learn about these extreme quiescent galaxies, or to confirm whether any existed at earlier times. Here we report the spectroscopic confirmation of a massive quiescent galaxy, GS-9209, at redshift, z = 4.658, just 1.25 billion years after the Big Bang, using the JWST Near-Infrared Spectrograph (NIRSpec). From these data we infer a stellar mass of M* = 3.8 ± 0.2 × 1010 M⊙, which formed over a roughly 200 Myr period before this galaxy quenched its star-formation activity at [Formula: see text], when the Universe was approximately 800 Myr old. This galaxy is both a likely descendent of the highest-redshift submillimetre galaxies and quasars, and a likely progenitor for the dense, ancient cores of the most massive local galaxies.

14.
Nature ; 614(7947): 318-325, 2023 02.
Artigo em Inglês | MEDLINE | ID: mdl-36599978

RESUMO

Rare CD4 T cells that contain HIV under antiretroviral therapy represent an important barrier to HIV cure1-3, but the infeasibility of isolating and characterizing these cells in their natural state has led to uncertainty about whether they possess distinctive attributes that HIV cure-directed therapies might exploit. Here we address this challenge using a microfluidic technology that isolates the transcriptomes of HIV-infected cells based solely on the detection of HIV DNA. HIV-DNA+ memory CD4 T cells in the blood from people receiving antiretroviral therapy showed inhibition of six transcriptomic pathways, including death receptor signalling, necroptosis signalling and antiproliferative Gα12/13 signalling. Moreover, two groups of genes identified by network co-expression analysis were significantly associated with HIV-DNA+ cells. These genes (n = 145) accounted for just 0.81% of the measured transcriptome and included negative regulators of HIV transcription that were higher in HIV-DNA+ cells, positive regulators of HIV transcription that were lower in HIV-DNA+ cells, and other genes involved in RNA processing, negative regulation of mRNA translation, and regulation of cell state and fate. These findings reveal that HIV-infected memory CD4 T cells under antiretroviral therapy are a distinctive population with host gene expression patterns that favour HIV silencing, cell survival and cell proliferation, with important implications for the development of HIV cure strategies.


Assuntos
Linfócitos T CD4-Positivos , Regulação Viral da Expressão Gênica , Infecções por HIV , HIV-1 , Latência Viral , Humanos , Linfócitos T CD4-Positivos/citologia , Linfócitos T CD4-Positivos/efeitos dos fármacos , Linfócitos T CD4-Positivos/metabolismo , Linfócitos T CD4-Positivos/virologia , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , DNA Viral/isolamento & purificação , Regulação Viral da Expressão Gênica/efeitos dos fármacos , Infecções por HIV/tratamento farmacológico , Infecções por HIV/genética , Infecções por HIV/imunologia , Infecções por HIV/virologia , HIV-1/efeitos dos fármacos , HIV-1/genética , HIV-1/isolamento & purificação , HIV-1/patogenicidade , Memória Imunológica , Microfluídica , Necroptose/efeitos dos fármacos , Transdução de Sinais/efeitos dos fármacos , Transcriptoma/efeitos dos fármacos , Latência Viral/efeitos dos fármacos , Antirretrovirais/farmacologia , Antirretrovirais/uso terapêutico
15.
Nature ; 613(7943): 280-286, 2023 01.
Artigo em Inglês | MEDLINE | ID: mdl-36631649

RESUMO

Macroscopic electric motors continue to have a large impact on almost every aspect of modern society. Consequently, the effort towards developing molecular motors1-3 that can be driven by electricity could not be more timely. Here we describe an electric molecular motor based on a [3]catenane4,5, in which two cyclobis(paraquat-p-phenylene)6 (CBPQT4+) rings are powered by electricity in solution to circumrotate unidirectionally around a 50-membered loop. The constitution of the loop ensures that both rings undergo highly (85%) unidirectional movement under the guidance of a flashing energy ratchet7,8, whereas the interactions between the two rings give rise to a two-dimensional potential energy surface (PES) similar to that shown by FOF1 ATP synthase9. The unidirectionality is powered by an oscillating10 voltage11,12 or external modulation of the redox potential13. Initially, we focused our attention on the homologous [2]catenane, only to find that the kinetic asymmetry was insufficient to support unidirectional movement of the sole ring. Accordingly, we incorporated a second CBPQT4+ ring to provide further symmetry breaking by interactions between the two mobile rings. This demonstration of electrically driven continual circumrotatory motion of two rings around a loop in a [3]catenane is free from the production of waste products and represents an important step towards surface-bound14 electric molecular motors.

16.
Nature ; 619(7968): 143-150, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-37380764

RESUMO

Caloric restriction that promotes weight loss is an effective strategy for treating non-alcoholic fatty liver disease and improving insulin sensitivity in people with type 2 diabetes1. Despite its effectiveness, in most individuals, weight loss is usually not maintained partly due to physiological adaptations that suppress energy expenditure, a process known as adaptive thermogenesis, the mechanistic underpinnings of which are unclear2,3. Treatment of rodents fed a high-fat diet with recombinant growth differentiating factor 15 (GDF15) reduces obesity and improves glycaemic control through glial-cell-derived neurotrophic factor family receptor α-like (GFRAL)-dependent suppression of food intake4-7. Here we find that, in addition to suppressing appetite, GDF15 counteracts compensatory reductions in energy expenditure, eliciting greater weight loss and reductions in non-alcoholic fatty liver disease (NAFLD) compared to caloric restriction alone. This effect of GDF15 to maintain energy expenditure during calorie restriction requires a GFRAL-ß-adrenergic-dependent signalling axis that increases fatty acid oxidation and calcium futile cycling in the skeletal muscle of mice. These data indicate that therapeutic targeting of the GDF15-GFRAL pathway may be useful for maintaining energy expenditure in skeletal muscle during caloric restriction.


Assuntos
Metabolismo Energético , Fator 15 de Diferenciação de Crescimento , Músculo Esquelético , Redução de Peso , Animais , Humanos , Camundongos , Depressores do Apetite/metabolismo , Depressores do Apetite/farmacologia , Depressores do Apetite/uso terapêutico , Restrição Calórica , Diabetes Mellitus Tipo 2/complicações , Diabetes Mellitus Tipo 2/metabolismo , Dieta Hiperlipídica , Ingestão de Alimentos/efeitos dos fármacos , Metabolismo Energético/efeitos dos fármacos , Fator 15 de Diferenciação de Crescimento/metabolismo , Fator 15 de Diferenciação de Crescimento/farmacologia , Fator 15 de Diferenciação de Crescimento/uso terapêutico , Músculo Esquelético/efeitos dos fármacos , Músculo Esquelético/metabolismo , Hepatopatia Gordurosa não Alcoólica/complicações , Hepatopatia Gordurosa não Alcoólica/metabolismo , Hepatopatia Gordurosa não Alcoólica/terapia , Receptores Adrenérgicos beta/metabolismo , Redução de Peso/efeitos dos fármacos
17.
Nature ; 622(7984): 707-711, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37579792

RESUMO

During the first 500 million years of cosmic history, the first stars and galaxies formed, seeding the Universe with heavy elements and eventually reionizing the intergalactic medium1-3. Observations with the James Webb Space Telescope (JWST) have uncovered a surprisingly high abundance of candidates for early star-forming galaxies, with distances (redshifts, z), estimated from multiband photometry, as large as z ≈ 16, far beyond pre-JWST limits4-9. Although such photometric redshifts are generally robust, they can suffer from degeneracies and occasionally catastrophic errors. Spectroscopic measurements are required to validate these sources and to reliably quantify physical properties that can constrain galaxy formation models and cosmology10. Here we present JWST spectroscopy that confirms redshifts for two very luminous galaxies with z > 11, and also demonstrates that another candidate with suggested z ≈ 16 instead has z = 4.9, with an unusual combination of nebular line emission and dust reddening that mimics the colours expected for much more distant objects. These results reinforce evidence for the early, rapid formation of remarkably luminous galaxies while also highlighting the necessity of spectroscopic verification. The large abundance of bright, early galaxies may indicate shortcomings in current galaxy formation models or deviations from physical properties (such as the stellar initial mass function) that are generally believed to hold at later times.

18.
Nature ; 618(7967): 917-920, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-37380688

RESUMO

When main-sequence stars expand into red giants, they are expected to engulf close-in planets1-5. Until now, the absence of planets with short orbital periods around post-expansion, core-helium-burning red giants6-8 has been interpreted as evidence that short-period planets around Sun-like stars do not survive the giant expansion phase of their host stars9. Here we present the discovery that the giant planet 8 Ursae Minoris b10 orbits a core-helium-burning red giant. At a distance of only 0.5 AU from its host star, the planet would have been engulfed by its host star, which is predicted by standard single-star evolution to have previously expanded to a radius of 0.7 AU. Given the brief lifetime of helium-burning giants, the nearly circular orbit of the planet is challenging to reconcile with scenarios in which the planet survives by having a distant orbit initially. Instead, the planet may have avoided engulfment through a stellar merger that either altered the evolution of the host star or produced 8 Ursae Minoris b as a second-generation planet11. This system shows that core-helium-burning red giants can harbour close planets and provides evidence for the role of non-canonical stellar evolution in the extended survival of late-stage exoplanetary systems.

19.
Trends Biochem Sci ; 49(2): 134-144, 2024 02.
Artigo em Inglês | MEDLINE | ID: mdl-38102017

RESUMO

Tripartite ATP-independent periplasmic (TRAP) transporters are nutrient-uptake systems found in bacteria and archaea. These evolutionary divergent transporter systems couple a substrate-binding protein (SBP) to an elevator-type secondary transporter, which is a first-of-its-kind mechanism of transport. Here, we highlight breakthrough TRAP transporter structures and recent functional data that probe the mechanism of transport. Furthermore, we discuss recent structural and biophysical studies of the ion transporter superfamily (ITS) members and highlight mechanistic principles that are relevant for further exploration of the TRAP transporter system.


Assuntos
Proteínas de Bactérias , Proteínas de Membrana Transportadoras , Proteínas de Bactérias/metabolismo , Proteínas de Membrana Transportadoras/química , Proteínas de Transporte/metabolismo , Bactérias/metabolismo , Transporte Biológico
20.
Cell ; 154(4): 775-88, 2013 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-23932120

RESUMO

RNA polymerase II (RNAPII) lies at the core of dynamic control of gene expression. Using 53 RNAPII point mutants, we generated a point mutant epistatic miniarray profile (pE-MAP) comprising ∼60,000 quantitative genetic interactions in Saccharomyces cerevisiae. This analysis enabled functional assignment of RNAPII subdomains and uncovered connections between individual regions and other protein complexes. Using splicing microarrays and mutants that alter elongation rates in vitro, we found an inverse relationship between RNAPII speed and in vivo splicing efficiency. Furthermore, the pE-MAP classified fast and slow mutants that favor upstream and downstream start site selection, respectively. The striking coordination of polymerization rate with transcription initiation and splicing suggests that transcription rate is tuned to regulate multiple gene expression steps. The pE-MAP approach provides a powerful strategy to understand other multifunctional machines at amino acid resolution.


Assuntos
Epistasia Genética , RNA Polimerase II/genética , RNA Polimerase II/metabolismo , Saccharomyces cerevisiae/enzimologia , Saccharomyces cerevisiae/genética , Alelos , Estudo de Associação Genômica Ampla , Mutação Puntual , RNA Polimerase II/química , Splicing de RNA , Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Fatores de Transcrição/metabolismo , Sítio de Iniciação de Transcrição , Transcrição Gênica , Transcriptoma
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