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1.
Nat Commun ; 11(1): 4666, 2020 09 16.
Artigo em Inglês | MEDLINE | ID: mdl-32938943

RESUMO

Intercalated discs (ICD), specific cell-to-cell contacts that connect adjacent cardiomyocytes, ensure mechanical and electrochemical coupling during contraction of the heart. Mutations in genes encoding ICD components are linked to cardiovascular diseases. Here, we show that loss of Xinß, a newly-identified component of ICDs, results in cardiomyocyte proliferation defects and cardiomyopathy. We uncovered a role for Xinß in signaling via the Hippo-YAP pathway by recruiting NF2 to the ICD to modulate cardiac function. In Xinß mutant hearts levels of phosphorylated NF2 are substantially reduced, suggesting an impairment of Hippo-YAP signaling. Cardiac-specific overexpression of YAP rescues cardiac defects in Xinß knock-out mice-indicating a functional and genetic interaction between Xinß and YAP. Our study reveals a molecular mechanism by which cardiac-expressed intercalated disc protein Xinß modulates Hippo-YAP signaling to control heart development and cardiac function in a tissue specific manner. Consequently, this pathway may represent a therapeutic target for the treatment of cardiovascular diseases.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Proteínas de Ciclo Celular/metabolismo , Proteínas do Citoesqueleto/metabolismo , Proteínas de Ligação a DNA/metabolismo , Proteínas com Domínio LIM/metabolismo , Miócitos Cardíacos/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/genética , Animais , Cardiomiopatia Dilatada/genética , Comunicação Celular , Proteínas de Ciclo Celular/genética , Proliferação de Células , Proteínas do Citoesqueleto/genética , Proteínas de Ligação a DNA/genética , Feminino , Regulação da Expressão Gênica no Desenvolvimento , Ventrículos do Coração/crescimento & desenvolvimento , Proteínas com Domínio LIM/genética , Masculino , Camundongos Endogâmicos C57BL , Camundongos Knockout , Mutação , Miócitos Cardíacos/citologia , Miócitos Cardíacos/patologia , Neurofibromina 2/genética , Neurofibromina 2/metabolismo , Proteínas Nucleares/genética , Transdução de Sinais
2.
Nat Commun ; 11(1): 4578, 2020 09 14.
Artigo em Inglês | MEDLINE | ID: mdl-32929090

RESUMO

Thalidomide and its derivatives exert not only therapeutic effects as immunomodulatory drugs (IMiDs) but also adverse effects such as teratogenicity, which are due in part to different C2H2 zinc-finger (ZF) transcription factors, IKZF1 (or IKZF3) and SALL4, respectively. Here, we report the structural bases for the SALL4-specific proteasomal degradation induced by 5-hydroxythalidomide, a primary thalidomide metabolite generated by the enzymatic activity of cytochrome P450 isozymes, through the interaction with cereblon (CRBN). The crystal structure of the metabolite-mediated human SALL4-CRBN complex and mutagenesis studies elucidate the complex formation enhanced by the interaction between CRBN and an additional hydroxy group of (S)-5-hydroxythalidomide and the variation in the second residue of ß-hairpin structure that underlies the C2H2 ZF-type neo-morphic substrate (neosubstrate) selectivity of 5-hydroxythalidomide. These findings deepen our understanding of the pharmaceutical action of IMiDs and provide structural evidence that the glue-type E3 ligase modulators cause altered neosubstrate specificities through their metabolism.


Assuntos
Fatores Imunológicos/química , Fatores Imunológicos/farmacologia , Talidomida/análogos & derivados , Proteínas Adaptadoras de Transdução de Sinal/química , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Sequência de Aminoácidos , Células HEK293 , Humanos , Ligação Proteica/efeitos dos fármacos , Domínios Proteicos , Estereoisomerismo , Homologia Estrutural de Proteína , Especificidade por Substrato , Talidomida/química , Talidomida/farmacologia , Fatores de Transcrição/química , Fatores de Transcrição/metabolismo
3.
Nat Commun ; 11(1): 4581, 2020 09 11.
Artigo em Inglês | MEDLINE | ID: mdl-32917893

RESUMO

Yes-associated protein 1 (YAP) is a transcriptional regulator with critical roles in mechanotransduction, organ size control, and regeneration. Here, using advanced tools for real-time visualization of native YAP and target gene transcription dynamics, we show that a cycle of fast exodus of nuclear YAP to the cytoplasm followed by fast reentry to the nucleus ("localization-resets") activates YAP target genes. These "resets" are induced by calcium signaling, modulation of actomyosin contractility, or mitosis. Using nascent-transcription reporter knock-ins of YAP target genes, we show a strict association between these resets and downstream transcription. Oncogenically-transformed cell lines lack localization-resets and instead show dramatically elevated rates of nucleocytoplasmic shuttling of YAP, suggesting an escape from compartmentalization-based control. The single-cell localization and transcription traces suggest that YAP activity is not a simple linear function of nuclear enrichment and point to a model of transcriptional activation based on nucleocytoplasmic exchange properties of YAP.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Fatores de Transcrição/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/genética , Sistemas CRISPR-Cas , Cálcio/metabolismo , Linhagem Celular Tumoral , Núcleo Celular/metabolismo , Citoplasma/metabolismo , Regulação da Expressão Gênica , Técnicas de Introdução de Genes , Células HEK293 , Humanos , Mecanotransdução Celular/fisiologia , Oncogenes/genética , Fatores de Transcrição/genética
4.
Nat Commun ; 11(1): 4576, 2020 09 11.
Artigo em Inglês | MEDLINE | ID: mdl-32917905

RESUMO

Endosome maturation depends on membrane contact sites (MCSs) formed between endoplasmic reticulum (ER) and endolysosomes (LyLEs). The mechanism underlying lipid supply for this process and its pathophysiological relevance remains unclear, however. Here, we identify PDZD8-the mammalian ortholog of a yeast ERMES subunit-as a protein that interacts with protrudin, which is located at ER-LyLE MCSs. Protrudin and PDZD8 promote the formation of ER-LyLE MCSs, and PDZD8 shows the ability to extract various lipids from the ER. Overexpression of both protrudin and PDZD8 in HeLa cells, as well as their depletion in mouse primary neurons, impairs endosomal homeostasis by inducing the formation of abnormal large vacuoles reminiscent of those apparent in spastin- or REEP1-deficient neurons. The protrudin-PDZD8 system is also essential for the establishment of neuronal polarity. Our results suggest that protrudin and PDZD8 cooperatively promote endosome maturation by mediating ER-LyLE tethering and lipid extraction at MCSs, thereby maintaining neuronal polarity and integrity.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Endossomos/fisiologia , Metabolismo dos Lipídeos , Neurônios/metabolismo , Proteínas de Transporte Vesicular/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/genética , Animais , Modelos Animais de Doenças , Retículo Endoplasmático/metabolismo , Feminino , Células HEK293 , Células HeLa , Humanos , Lipídeos , Lipossomos/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos ICR , Camundongos Knockout , Mitocôndrias , Domínios Proteicos , Proteômica , Proteínas Recombinantes , Saccharomyces cerevisiae/metabolismo , Proteínas de Transporte Vesicular/genética
5.
Nat Commun ; 11(1): 4766, 2020 09 21.
Artigo em Inglês | MEDLINE | ID: mdl-32958778

RESUMO

Germline telomere maintenance defects are associated with an increased incidence of inflammatory diseases in humans, yet whether and how telomere dysfunction causes inflammation are not known. Here, we show that telomere dysfunction drives pATM/c-ABL-mediated activation of the YAP1 transcription factor, up-regulating the major pro-inflammatory factor, pro-IL-18. The colonic microbiome stimulates cytosolic receptors activating caspase-1 which cleaves pro-IL-18 into mature IL-18, leading to recruitment of interferon (IFN)-γ-secreting T cells and intestinal inflammation. Correspondingly, patients with germline telomere maintenance defects exhibit DNA damage (γH2AX) signaling together with elevated YAP1 and IL-18 expression. In mice with telomere dysfunction, telomerase reactivation in the intestinal epithelium or pharmacological inhibition of ATM, YAP1, or caspase-1 as well as antibiotic treatment, dramatically reduces IL-18 and intestinal inflammation. Thus, telomere dysfunction-induced activation of the ATM-YAP1-pro-IL-18 pathway in epithelium is a key instigator of tissue inflammation.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Proteínas de Ciclo Celular/metabolismo , Inflamação/patologia , Telômero/patologia , Proteínas Adaptadoras de Transdução de Sinal/antagonistas & inibidores , Proteínas Adaptadoras de Transdução de Sinal/genética , Animais , Antibacterianos/uso terapêutico , Proteínas Mutadas de Ataxia Telangiectasia/antagonistas & inibidores , Proteínas Mutadas de Ataxia Telangiectasia/metabolismo , Caspase 1/metabolismo , Proteínas de Ciclo Celular/antagonistas & inibidores , Proteínas de Ciclo Celular/genética , Criança , Colo/metabolismo , Colo/microbiologia , Colo/patologia , Gastroenteropatias/patologia , Microbioma Gastrointestinal/efeitos dos fármacos , Microbioma Gastrointestinal/fisiologia , Humanos , Inflamação/tratamento farmacológico , Inflamação/metabolismo , Inflamação/microbiologia , Interleucina-18/genética , Interleucina-18/metabolismo , Mucosa Intestinal/metabolismo , Mucosa Intestinal/patologia , Camundongos , Camundongos Mutantes , Fosforilação , Precursores de Proteínas/genética , Precursores de Proteínas/metabolismo , Transdução de Sinais , Telomerase/genética , Telomerase/metabolismo
6.
Science ; 369(6506): 984-988, 2020 08 21.
Artigo em Inglês | MEDLINE | ID: mdl-32820125

RESUMO

Germinal center (GC) responses potentiate the generation of follicular regulatory T (TFR) cells. However, the molecular cues driving TFR cell formation remain unknown. Here, we show that sclerostin domain-containing protein 1 (SOSTDC1), secreted by a subpopulation of follicular helper T (TFH) cells and T-B cell border-enriched fibroblastic reticular cells, is developmentally required for TFR cell generation. Fate tracking and transcriptome assessment in reporter mice establishes SOSTDC1-expressing TFH cells as a distinct T cell population that develops after SOSTDC1- TFH cells and loses the ability to help B cells for antibody production. Notably, Sostdc1 ablation in TFH cells results in substantially reduced TFR cell numbers and consequently elevated GC responses. Mechanistically, SOSTDC1 blocks the WNT-ß-catenin axis and facilitates TFR cell differentiation.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Linfócitos T Auxiliares-Indutores/imunologia , Linfócitos T Reguladores/imunologia , Proteínas Adaptadoras de Transdução de Sinal/genética , Animais , Linfócitos B/imunologia , Diferenciação Celular/genética , Diferenciação Celular/imunologia , Centro Germinativo/imunologia , Ativação Linfocitária/genética , Ativação Linfocitária/imunologia , Contagem de Linfócitos , Camundongos , Camundongos Mutantes , Proteínas Wnt/metabolismo , beta Catenina/metabolismo
7.
Nature ; 585(7824): 251-255, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32848248

RESUMO

Mutation of C9orf72 is the most prevalent defect associated with amyotrophic lateral sclerosis and frontotemporal degeneration1. Together with hexanucleotide-repeat expansion2,3, haploinsufficiency of C9orf72 contributes to neuronal dysfunction4-6. Here we determine the structure of the C9orf72-SMCR8-WDR41 complex by cryo-electron microscopy. C9orf72 and SMCR8 both contain longin and DENN (differentially expressed in normal and neoplastic cells) domains7, and WDR41 is a ß-propeller protein that binds to SMCR8 such that the whole structure resembles an eye slip hook. Contacts between WDR41 and the DENN domain of SMCR8 drive the lysosomal localization of the complex in conditions of amino acid starvation. The structure suggested that C9orf72-SMCR8 is a GTPase-activating protein (GAP), and we found that C9orf72-SMCR8-WDR41 acts as a GAP for the ARF family of small GTPases. These data shed light on the function of C9orf72 in normal physiology, and in amyotrophic lateral sclerosis and frontotemporal degeneration.


Assuntos
Esclerose Amiotrófica Lateral/genética , Proteínas Relacionadas à Autofagia/química , Proteína C9orf72/química , Proteína C9orf72/genética , Proteínas de Transporte/química , Microscopia Crioeletrônica , Demência Frontotemporal/genética , Haploinsuficiência , Complexos Multiproteicos/química , Proteínas Adaptadoras de Transdução de Sinal/química , Proteínas Adaptadoras de Transdução de Sinal/genética , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Esclerose Amiotrófica Lateral/metabolismo , Proteínas Relacionadas à Autofagia/deficiência , Proteínas Relacionadas à Autofagia/metabolismo , Proteínas Relacionadas à Autofagia/ultraestrutura , Proteína C9orf72/metabolismo , Proteínas de Transporte/genética , Proteínas de Transporte/metabolismo , Proteínas de Transporte/ultraestrutura , Demência Frontotemporal/metabolismo , Humanos , Lisossomos/metabolismo , Modelos Moleculares , Complexos Multiproteicos/genética , Complexos Multiproteicos/metabolismo , Complexos Multiproteicos/ultraestrutura , Proteínas Mutantes/genética , Proteínas Mutantes/metabolismo , Mutação , Domínios Proteicos
8.
PLoS One ; 15(7): e0225351, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32735563

RESUMO

Endothelial cilia are found in a variety of tissues including the cranial vasculature of zebrafish embryos. Recently, endothelial cells in the developing mouse retina were reported to also possess primary cilia that are potentially involved in vascular remodeling. Fish carrying mutations in intraflagellar transport (ift) genes have disrupted cilia and have been reported to have an increased rate of spontaneous intracranial hemorrhage (ICH), potentially due to disruption of the sonic hedgehog (shh) signaling pathway. However, it remains unknown whether the endothelial cells forming the retinal microvasculature in zebrafish also possess cilia, and whether endothelial cilia are necessary for development and maintenance of the blood-retinal barrier (BRB). In the present study, we found that the endothelial cells lining the zebrafish hyaloid vasculature possess primary cilia during development. To determine whether endothelial cilia are necessary for BRB integrity, ift57, ift88, and ift172 mutants, which lack cilia, were crossed with the double-transgenic zebrafish strain Tg(l-fabp:DBP-EGFP;flk1:mCherry). This strain expresses a vitamin D-binding protein (DBP) fused to enhanced green fluorescent protein (EGFP) as a tracer in the blood plasma, while the endothelial cells forming the vasculature are tagged by mCherry. The Ift mutant fish develop a functional BRB, indicating that endothelial cilia are not necessary for early BRB integrity. Additionally, although treatment of zebrafish larvae with Shh inhibitor cyclopamine results in BRB breakdown, the Ift mutant fish were not sensitized to cyclopamine-induced BRB breakdown.


Assuntos
Barreira Hematorretiniana/metabolismo , Cílios/metabolismo , Células Endoteliais/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/genética , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Animais , Animais Geneticamente Modificados , Barreira Hematorretiniana/efeitos dos fármacos , Barreira Hematorretiniana/fisiologia , Células Endoteliais/citologia , Proteínas Hedgehog/antagonistas & inibidores , Proteínas Hedgehog/genética , Proteínas Hedgehog/metabolismo , Larva/metabolismo , Mutagênese , Vasos Retinianos/citologia , Transdução de Sinais , Alcaloides de Veratrum/farmacologia , Peixe-Zebra/crescimento & desenvolvimento , Peixe-Zebra/metabolismo , Proteínas de Peixe-Zebra/genética , Proteínas de Peixe-Zebra/metabolismo
9.
Nat Commun ; 11(1): 4102, 2020 08 14.
Artigo em Inglês | MEDLINE | ID: mdl-32796823

RESUMO

Emerging evidence suggests that intestinal stromal cells (IntSCs) play essential roles in maintaining intestinal homeostasis. However, the extent of heterogeneity within the villi stromal compartment and how IntSCs regulate the structure and function of specialized intestinal lymphatic capillary called lacteal remain elusive. Here we show that selective hyperactivation or depletion of YAP/TAZ in PDGFRß+ IntSCs leads to lacteal sprouting or regression with junctional disintegration and impaired dietary fat uptake. Indeed, mechanical or osmotic stress regulates IntSC secretion of VEGF-C mediated by YAP/TAZ. Single-cell RNA sequencing delineated novel subtypes of villi fibroblasts that upregulate Vegfc upon YAP/TAZ activation. These populations of fibroblasts were distributed in proximity to lacteal, suggesting that they constitute a peri-lacteal microenvironment. Our findings demonstrate the heterogeneity of IntSCs and reveal that distinct subsets of villi fibroblasts regulate lacteal integrity through YAP/TAZ-induced VEGF-C secretion, providing new insights into the dynamic regulatory mechanisms behind lymphangiogenesis and lymphatic remodeling.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Proteínas de Ciclo Celular/metabolismo , Fibroblastos/metabolismo , Mucosa Intestinal/metabolismo , Fatores de Transcrição/metabolismo , Fator C de Crescimento do Endotélio Vascular/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/genética , Animais , Proteínas de Ciclo Celular/genética , Células Cultivadas , Análise por Conglomerados , Ensaio de Imunoadsorção Enzimática , Fibroblastos/ultraestrutura , Citometria de Fluxo , Imunofluorescência , Hibridização in Situ Fluorescente , Mucosa Intestinal/ultraestrutura , Linfangiogênese/genética , Linfangiogênese/fisiologia , Camundongos , Camundongos Endogâmicos C57BL , Microscopia Eletrônica , Neovascularização Fisiológica/genética , Neovascularização Fisiológica/fisiologia , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Fatores de Transcrição/genética , Fator C de Crescimento do Endotélio Vascular/genética
10.
Nat Commun ; 11(1): 3866, 2020 07 31.
Artigo em Inglês | MEDLINE | ID: mdl-32737287

RESUMO

Upon severe head injury (HI), blood vessels of the meninges and brain parenchyma are inevitably damaged. While limited vascular regeneration of the injured brain has been studied extensively, our understanding of meningeal vascular regeneration following head injury is quite limited. Here, we identify key pathways governing meningeal vascular regeneration following HI. Rapid and complete vascular regeneration in the meninges is predominantly driven by VEGFR2 signaling. Substantial increase of VEGFR2 is observed in both human patients and mouse models of HI, and endothelial cell-specific deletion of Vegfr2 in the latter inhibits meningeal vascular regeneration. We further identify the facilitating, stabilizing and arresting roles of Tie2, PDGFRß and Dll4 signaling, respectively, in meningeal vascular regeneration. Prolonged inhibition of this angiogenic process following HI compromises immunological and stromal integrity of the injured meninges. These findings establish a molecular framework for meningeal vascular regeneration after HI, and may guide development of wound healing therapeutics.


Assuntos
Traumatismos Craniocerebrais/genética , Células Endoteliais/metabolismo , Neovascularização Fisiológica/genética , Regeneração/genética , Transdução de Sinais/genética , Receptor 2 de Fatores de Crescimento do Endotélio Vascular/genética , Proteínas Adaptadoras de Transdução de Sinal/genética , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Animais , Vasos Sanguíneos/metabolismo , Vasos Sanguíneos/patologia , Proteínas de Ligação ao Cálcio/genética , Proteínas de Ligação ao Cálcio/metabolismo , Circulação Cerebrovascular , Traumatismos Craniocerebrais/metabolismo , Traumatismos Craniocerebrais/patologia , Modelos Animais de Doenças , Células Endoteliais/patologia , Regulação da Expressão Gênica/genética , Humanos , Macrófagos/metabolismo , Macrófagos/patologia , Meninges/lesões , Meninges/metabolismo , Camundongos , Camundongos Knockout , Receptor beta de Fator de Crescimento Derivado de Plaquetas/genética , Receptor beta de Fator de Crescimento Derivado de Plaquetas/metabolismo , Receptor TIE-2/genética , Receptor TIE-2/metabolismo , Receptor 2 de Fatores de Crescimento do Endotélio Vascular/metabolismo , Cicatrização/genética
11.
Nat Commun ; 11(1): 4187, 2020 08 21.
Artigo em Inglês | MEDLINE | ID: mdl-32826901

RESUMO

EHBP1 is an adaptor protein that regulates vesicular trafficking by recruiting Rab8 family members and Eps15-homology domain-containing proteins 1/2 (EHD1/2). It also links endosomes to the actin cytoskeleton. However, the underlying molecular mechanism of activation of EHBP1 actin-binding activity is unclear. Here, we show that both termini of EHBP1 have membrane targeting potential. EHBP1 associates with PI(3)P, PI(5)P, and phosphatidylserine via its N-terminal C2 domain. We show that in the absence of Rab8 family members, the C-terminal bivalent Mical/EHBP Rab binding (bMERB) domain forms an intramolecular complex with its central calponin homology (CH) domain and auto-inhibits actin binding. Rab8 binding to the bMERB domain relieves this inhibition. We have analyzed the CH:bMERB auto-inhibited complex and the active bMERB:Rab8 complex biochemically and structurally. Together with structure-based mutational studies, this explains how binding of Rab8 frees the CH domain and allows it to interact with the actin cytoskeleton, leading to membrane tubulation.


Assuntos
Proteínas de Transporte/química , Proteínas de Transporte/metabolismo , Proteínas dos Microfilamentos/química , Proteínas dos Microfilamentos/metabolismo , Proteínas rab de Ligação ao GTP/química , Proteínas rab de Ligação ao GTP/metabolismo , Citoesqueleto de Actina/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/química , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Proteínas de Transporte/genética , Proteínas dos Microfilamentos/genética , Modelos Moleculares , Fosfatos de Fosfatidilinositol/metabolismo , Ligação Proteica , Conformação Proteica , Domínios Proteicos , Domínios e Motivos de Interação entre Proteínas , Transporte Proteico/fisiologia , Alinhamento de Sequência , Proteínas de Transporte Vesicular , Proteínas rab de Ligação ao GTP/genética
12.
Nat Commun ; 11(1): 4268, 2020 08 26.
Artigo em Inglês | MEDLINE | ID: mdl-32848159

RESUMO

Current efforts in the proteolysis targeting chimera (PROTAC) field mostly focus on choosing an appropriate E3 ligase for the target protein, improving the binding affinities towards the target protein and the E3 ligase, and optimizing the PROTAC linker. However, due to the large molecular weights of PROTACs, their cellular uptake remains an issue. Through comparing how different warhead chemistry, reversible noncovalent (RNC), reversible covalent (RC), and irreversible covalent (IRC) binders, affects the degradation of Bruton's Tyrosine Kinase (BTK), we serendipitously discover that cyano-acrylamide-based reversible covalent chemistry can significantly enhance the intracellular accumulation and target engagement of PROTACs and develop RC-1 as a reversible covalent BTK PROTAC with a high target occupancy as its corresponding kinase inhibitor and effectiveness as a dual functional inhibitor and degrader, a different mechanism-of-action for PROTACs. Importantly, this reversible covalent strategy is generalizable to improve other PROTACs, opening a path to enhance PROTAC efficacy.


Assuntos
Tirosina Quinase da Agamaglobulinemia/metabolismo , Ubiquitina-Proteína Ligases/metabolismo , Acrilamidas/química , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Tirosina Quinase da Agamaglobulinemia/genética , Linhagem Celular , Sobrevivência Celular , Corantes Fluorescentes , Meia-Vida , Humanos , Espaço Intracelular/metabolismo , Ligantes , Simulação de Dinâmica Molecular , Mutação , Fenômenos de Química Orgânica , Ligação Proteica , Domínios e Motivos de Interação entre Proteínas , Proteólise
13.
PLoS Pathog ; 16(8): e1008766, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32857822

RESUMO

Pathogens commonly disrupt the intestinal epithelial barrier; however, how the epithelial immune system senses the loss of intestinal barrier as a danger signal to activate self-defense is unclear. Through an unbiased approach in the model nematode Caenorhabditis elegans, we found that the EGL-44/TEAD transcription factor and its transcriptional activator YAP-1/YAP (Yes-associated protein) were activated when the intestinal barrier was disrupted by infections with the pathogenic bacterium Pseudomonas aeruginosa PA14. Gene Ontology enrichment analysis of the genes containing the TEAD-binding sites revealed that "innate immune response" and "defense response to Gram-negative bacterium" were two top significantly overrepresented terms. Genetic inactivation of yap-1 and egl-44 significantly reduced the survival rate and promoted bacterial accumulation in worms after bacterial infections. Furthermore, we found that disturbance of the E-cadherin-based adherens junction triggered the nuclear translocation and activation of YAP-1/YAP in the gut of worms. Although YAP is a major downstream effector of the Hippo signaling, our study revealed that the activation of YAP-1/YAP was independent of the Hippo pathway during disruption of intestinal barrier. After screening 10 serine/threonine phosphatases, we identified that PP2A phosphatase was involved in the activation of YAP-1/YAP after intestinal barrier loss induced by bacterial infections. Additionally, our study demonstrated that the function of YAP was evolutionarily conserved in mice. Our study highlights how the intestinal epithelium recognizes the loss of the epithelial barrier as a danger signal to deploy defenses against pathogens, uncovering an immune surveillance program in the intestinal epithelium.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Proteínas de Caenorhabditis elegans/metabolismo , Permeabilidade da Membrana Celular , Células Epiteliais/imunologia , Microbioma Gastrointestinal/imunologia , Salmonelose Animal/imunologia , Salmonella typhimurium/imunologia , Proteínas Adaptadoras de Transdução de Sinal/genética , Animais , Caenorhabditis elegans , Proteínas de Caenorhabditis elegans/genética , Células Epiteliais/metabolismo , Células Epiteliais/microbiologia , Células Epiteliais/patologia , Camundongos , Salmonelose Animal/metabolismo , Salmonelose Animal/microbiologia , Salmonelose Animal/patologia , Transdução de Sinais
14.
PLoS One ; 15(8): e0237034, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32745117

RESUMO

Production of IFN-γ is a key innate immune mechanism that limits replication of intracellular bacteria such as Francisella tularensis (Ft) until adaptive immune responses develop. Previously, we demonstrated that the host cell types responsible for IFN-γ production in response to murine Francisella infection include not only natural killer (NK) and T cells, but also a variety of myeloid cells. However, production of IFN-γ by mouse dendritic cells (DC) is controversial. Here, we directly demonstrated substantial production of IFN-γ by DC, as well as hybrid NK-DC, from LVS-infected wild type C57BL/6 or Rag1 knockout mice. We demonstrated that the numbers of conventional DC producing IFN-γ increased progressively over the course of 8 days of LVS infection. In contrast, the numbers of conventional NK cells producing IFN-γ, which represented about 40% of non-B/T IFN-γ-producing cells, peaked at day 4 after LVS infection and declined thereafter. This pattern was similar to that of hybrid NK-DC. To further confirm IFN-γ production by infected cells, DC and neutrophils were sorted from naïve and LVS-infected mice and analyzed for gene expression. Quantification of LVS by PCR revealed the presence of Ft DNA not only in macrophages, but also in highly purified, IFN-γ producing DC and neutrophils. Finally, production of IFN-γ by infected DC was confirmed by immunohistochemistry and confocal microscopy. Notably, IFN-γ production patterns similar to those in wild type mice were observed in cells derived from LVS-infected TLR2, TLR4, and TLR2xTLR9 knockout (KO) mice, but not from MyD88 KO mice. Taken together, these studies demonstrate the pivotal roles of DC and MyD88 in IFN-γ production and in initiating innate immune responses to this intracellular bacterium.


Assuntos
Interferon gama/metabolismo , Fator 88 de Diferenciação Mieloide/genética , Receptores Toll-Like/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Animais , Células Dendríticas/imunologia , Células Dendríticas/metabolismo , Feminino , Francisella tularensis/imunologia , Imunidade Inata/imunologia , Células Matadoras Naturais/metabolismo , Macrófagos/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Células Mieloides/metabolismo , Fator 88 de Diferenciação Mieloide/metabolismo , Neutrófilos/metabolismo , Baço/metabolismo , Linfócitos T/imunologia , Receptor 2 Toll-Like/metabolismo , Receptor 4 Toll-Like/metabolismo , Receptor Toll-Like 9/metabolismo , Receptores Toll-Like/imunologia , Tularemia/microbiologia
15.
PLoS Pathog ; 16(8): e1008730, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32776977

RESUMO

Kaposi's sarcoma (KS), caused by Kaposi's sarcoma-associated herpesvirus (KSHV), is a highly angioproliferative disseminated tumor of endothelial cells commonly found in AIDS patients. We have recently shown that KSHV-encoded viral interferon regulatory factor 1 (vIRF1) mediates KSHV-induced cell motility (PLoS Pathog. 2019 Jan 30;15(1):e1007578). However, the role of vIRF1 in KSHV-induced cellular transformation and angiogenesis remains unknown. Here, we show that vIRF1 promotes angiogenesis by upregulating sperm associated antigen 9 (SPAG9) using two in vivo angiogenesis models including the chick chorioallantoic membrane assay (CAM) and the matrigel plug angiogenesis assay in mice. Mechanistically, vIRF1 interacts with transcription factor Lef1 to promote SPAG9 transcription. vIRF1-induced SPAG9 promotes the interaction of mitogen-activated protein kinase kinase 4 (MKK4) with JNK1/2 to increase their phosphorylation, resulting in enhanced VEGFA expression, angiogenesis, cell proliferation and migration. Finally, genetic deletion of ORF-K9 from KSHV genome abolishes KSHV-induced cellular transformation and impairs angiogenesis. Our results reveal that vIRF1 transcriptionally activates SPAG9 expression to promote angiogenesis and tumorigenesis via activating JNK/VEGFA signaling. These novel findings define the mechanism of KSHV induction of the SPAG9/JNK/VEGFA pathway and establish the scientific basis for targeting this pathway for treating KSHV-associated cancers.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Herpesvirus Humano 8/metabolismo , Fatores Reguladores de Interferon/metabolismo , Proteína Quinase 8 Ativada por Mitógeno/metabolismo , Proteína Quinase 9 Ativada por Mitógeno/metabolismo , Sarcoma de Kaposi/metabolismo , Fator A de Crescimento do Endotélio Vascular/metabolismo , Proteínas Virais/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/genética , Animais , Transformação Celular Neoplásica , Herpesvirus Humano 8/genética , Interações Hospedeiro-Patógeno , Humanos , Fatores Reguladores de Interferon/genética , Masculino , Camundongos , Proteína Quinase 8 Ativada por Mitógeno/genética , Proteína Quinase 9 Ativada por Mitógeno/genética , Neovascularização Patológica/genética , Neovascularização Patológica/metabolismo , Neovascularização Patológica/fisiopatologia , Sarcoma de Kaposi/genética , Sarcoma de Kaposi/fisiopatologia , Sarcoma de Kaposi/virologia , Fator A de Crescimento do Endotélio Vascular/genética , Proteínas Virais/genética
16.
Gene ; 757: 144949, 2020 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-32679290

RESUMO

Melanocortin-2 receptor accessory protein (MRAP) has an unusual dual topology and influences the expression, localisation, signalling and internalisation of the melanocortin receptor 2 (MC2); the adrenocorticotropic hormone (ACTH) receptor. Mutations in MRAP are associated with familial glucocorticoid deficiency type-2 and evidence is emerging of the importance of MRAP in adrenal development and ACTH signalling. Human MRAP has two functional splice variants: MRAP-α and MRAP-ß, unlike MRAP-ß, MRAP-α has little expression in brain but is highly expressed in ovary. MRAP2, identified through whole human genome sequence analysis, has approximately 40% sequence homology to MRAP. MRAP2 facilitates MC2 localisation to the cell surface but not ACTH signalling. MRAP and MRAP2 have been found to regulate the surface expression and signalling of all melanocortin receptors (MC1-5). Additionally, MRAP2 moderates the signalling of the G-protein coupled receptors (GCPRs): orexin, prokineticin and GHSR1a; the ghrelin receptor. Whilst MRAP appears to be mainly involved in glucocorticoid synthesis, an important role is emerging for MRAP2 in regulating appetite and energy homeostasis. Transgenic models indicate the importance of MRAP in adrenal gland formation. Like MC3R and MC4R knockout mice, MRAP2 knockout mice have an obese phenotype. In vitro studies indicate that MRAP2 enhances the MC3 and MC4 response to the agonist αMSH, which, like ACTH, is produced through precursor polypeptide proopiomelanocortin (POMC) cleavage. Analysis of cohorts of individuals with obesity have revealed several MRAP2 genetic variants with loss of function mutations which are causative of monogenic hyperphagic obesity with hyperglycaemia and hypertension. MRAP2 may also be associated with female infertility. This review summarises current knowledge of MRAP and MRAP2, their influence on GPCR signalling, and focusses on pathophysiology, particularly familial glucocorticoid deficiency type-2 and obesity.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Insuficiência Adrenal/genética , Proteínas de Membrana/metabolismo , Erros Inatos do Metabolismo de Esteroides/genética , Proteínas Adaptadoras de Transdução de Sinal/química , Proteínas Adaptadoras de Transdução de Sinal/genética , Insuficiência Adrenal/metabolismo , Animais , Regulação do Apetite , Humanos , Insulina/metabolismo , Melanocortinas/metabolismo , Proteínas de Membrana/química , Proteínas de Membrana/genética , Erros Inatos do Metabolismo de Esteroides/metabolismo
17.
PLoS Biol ; 18(7): e3000780, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32687489

RESUMO

Cells adjust to nutrient deprivation by reversible translational shutdown. This is accompanied by maintaining inactive ribosomes in a hibernation state, in which they are bound by proteins with inhibitory and protective functions. In eukaryotes, such a function was attributed to suppressor of target of Myb protein 1 (Stm1; SERPINE1 mRNA-binding protein 1 [SERBP1] in mammals), and recently, late-annotated short open reading frame 2 (Lso2; coiled-coil domain containing short open reading frame 124 [CCDC124] in mammals) was found to be involved in translational recovery after starvation from stationary phase. Here, we present cryo-electron microscopy (cryo-EM) structures of translationally inactive yeast and human ribosomes. We found Lso2/CCDC124 accumulating on idle ribosomes in the nonrotated state, in contrast to Stm1/SERBP1-bound ribosomes, which display a rotated state. Lso2/CCDC124 bridges the decoding sites of the small with the GTPase activating center (GAC) of the large subunit. This position allows accommodation of the duplication of multilocus region 34 protein (Dom34)-dependent ribosome recycling system, which splits Lso2-containing, but not Stm1-containing, ribosomes. We propose a model in which Lso2 facilitates rapid translation reactivation by stabilizing the recycling-competent state of inactive ribosomes.


Assuntos
Proteínas de Ciclo Celular/química , Proteínas de Ciclo Celular/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/química , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Proteínas Ribossômicas/química , Proteínas Ribossômicas/metabolismo , Ribossomos/metabolismo , Proteínas de Saccharomyces cerevisiae/química , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Sequência de Aminoácidos , Sítios de Ligação , Sequência Conservada , Evolução Molecular , Células HEK293 , Humanos , Modelos Moleculares , Peptídeos/química , Ligação Proteica , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , RNA de Transferência/metabolismo , Proteínas de Ligação a RNA/metabolismo , Ribossomos/ultraestrutura , Saccharomyces cerevisiae/ultraestrutura , Relação Estrutura-Atividade
18.
Proc Natl Acad Sci U S A ; 117(32): 19388-19398, 2020 08 11.
Artigo em Inglês | MEDLINE | ID: mdl-32727906

RESUMO

CD8+ T cells play pivotal roles in eradicating pathogens and tumor cells. T cell receptor (TCR) signaling is vital for the optimal activation of CD8+ T cells. Upon TCR engagement, the transmembrane adapter protein LAT (linker for activation of T cells) recruits other key signaling molecules and forms the "LAT signalosome" for downstream signal transduction. However, little is known about which functional partners could restrain the formation of the LAT signalosome and inhibit CD8+ cytotoxic T lymphocyte (CTL)-mediated cytotoxicity. Here we have demonstrated that LRCH1 (leucine-rich repeats and calponin homology domain containing 1) directly binds LAT, reduces LAT phosphorylation and interaction with GRB2, and also promotes the endocytosis of LAT. Lrch1 -/- mice display better protection against influenza virus and Listeria infection, with enhanced CD8+ T cell proliferation and cytotoxicity. Adoptive transfer of Lrch1 -/- CD8+ CTLs leads to increased B16-MO5 tumor clearance in vivo. Furthermore, knockout of LRCH1 in human chimeric antigen receptor (CAR) T cells that recognize the liver tumor-associated antigen glypican-3 could improve CAR T cell migration and proliferation in vitro. These findings suggest LRCH1 as a potential translational target to improve T cell immunotherapy against infection and tumors.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Linfócitos T CD8-Positivos/imunologia , Proteínas de Membrana/metabolismo , Proteínas dos Microfilamentos/deficiência , Transdução de Sinais , Animais , Linfócitos T CD8-Positivos/metabolismo , Linfócitos T CD8-Positivos/transplante , Movimento Celular , Células Cultivadas , Citotoxicidade Imunológica , Endocitose , Proteína Adaptadora GRB2/metabolismo , Humanos , Imunoterapia Adotiva , Infecções/imunologia , Infecções/microbiologia , Infecções/virologia , Interferon gama/metabolismo , Neoplasias Pulmonares/terapia , Ativação Linfocitária , Camundongos , Camundongos Knockout , Proteínas dos Microfilamentos/genética , Proteínas dos Microfilamentos/metabolismo , Fosforilação , Ligação Proteica , Receptores de Antígenos de Linfócitos T/metabolismo , Receptores de Antígenos Quiméricos/metabolismo
19.
Nat Commun ; 11(1): 3301, 2020 07 03.
Artigo em Inglês | MEDLINE | ID: mdl-32620849

RESUMO

Many cellular stresses are transduced into apoptotic signals through modification or up-regulation of the BH3-only subfamily of BCL2 proteins. Through direct or indirect mechanisms, these proteins activate BAK and BAX to permeabilize the mitochondrial outer membrane. While the BH3-only proteins BIM, PUMA, and tBID have been confirmed to directly activate BAK through its canonical BH3 binding groove, whether the BH3-only proteins BMF, HRK or BIK can directly activate BAK is less clear. Here we show that BMF and HRK bind and directly activate BAK. Through NMR studies, site-directed mutagenesis, and advanced molecular dynamics simulations, we also find that BAK activation by BMF and possibly HRK involves a previously unrecognized binding groove formed by BAK α4, α6, and α7 helices. Alterations in this groove decrease the ability of BMF and HRK to bind BAK, permeabilize membranes and induce apoptosis, suggesting a potential role for this BH3-binding site in BAK activation.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Proteínas Reguladoras de Apoptose/metabolismo , Proteína Killer-Antagonista Homóloga a bcl-2/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/química , Proteínas Adaptadoras de Transdução de Sinal/genética , Sequência de Aminoácidos , Animais , Proteínas Reguladoras de Apoptose/química , Proteínas Reguladoras de Apoptose/genética , Sítios de Ligação/genética , Células Cultivadas , Humanos , Células Jurkat , Espectroscopia de Ressonância Magnética , Camundongos Knockout , Membranas Mitocondriais/metabolismo , Simulação de Dinâmica Molecular , Mutação , Ligação Proteica , Domínios Proteicos , Proteínas Proto-Oncogênicas c-bcl-2/química , Proteínas Proto-Oncogênicas c-bcl-2/genética , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Homologia de Sequência de Aminoácidos , Proteína Killer-Antagonista Homóloga a bcl-2/química , Proteína Killer-Antagonista Homóloga a bcl-2/genética
20.
Nat Commun ; 11(1): 3464, 2020 07 10.
Artigo em Inglês | MEDLINE | ID: mdl-32651375

RESUMO

DOCK (dedicator of cytokinesis) proteins are multidomain guanine nucleotide exchange factors (GEFs) for RHO GTPases that regulate intracellular actin dynamics. DOCK proteins share catalytic (DOCKDHR2) and membrane-associated (DOCKDHR1) domains. The structurally-related DOCK1 and DOCK2 GEFs are specific for RAC, and require ELMO (engulfment and cell motility) proteins for function. The N-terminal RAS-binding domain (RBD) of ELMO (ELMORBD) interacts with RHOG to modulate DOCK1/2 activity. Here, we determine the cryo-EM structures of DOCK2-ELMO1 alone, and as a ternary complex with RAC1, together with the crystal structure of a RHOG-ELMO2RBD complex. The binary DOCK2-ELMO1 complex adopts a closed, auto-inhibited conformation. Relief of auto-inhibition to an active, open state, due to a conformational change of the ELMO1 subunit, exposes binding sites for RAC1 on DOCK2DHR2, and RHOG and BAI GPCRs on ELMO1. Our structure explains how up-stream effectors, including DOCK2 and ELMO1 phosphorylation, destabilise the auto-inhibited state to promote an active GEF.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Proteínas Ativadoras de GTPase/metabolismo , Fatores de Troca do Nucleotídeo Guanina/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/genética , Calorimetria , Proteínas Ativadoras de GTPase/genética , Fatores de Troca do Nucleotídeo Guanina/genética , Células HEK293 , Células HeLa , Humanos , Immunoblotting , Cinética , Microscopia Eletrônica , Fosforilação , Proteínas rac1 de Ligação ao GTP/genética , Proteínas rac1 de Ligação ao GTP/metabolismo , Proteínas rho de Ligação ao GTP/genética , Proteínas rho de Ligação ao GTP/metabolismo
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