Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 117.660
Filtrar
1.
Science ; 383(6684): 732-739, 2024 Feb 16.
Artigo em Inglês | MEDLINE | ID: mdl-38359129

RESUMO

Polygalacturonase-inhibiting proteins (PGIPs) interact with pathogen-derived polygalacturonases to inhibit their virulence-associated plant cell wall-degrading activity but stimulate immunity-inducing oligogalacturonide production. Here we show that interaction between Phaseolus vulgaris PGIP2 (PvPGIP2) and Fusarium phyllophilum polygalacturonase (FpPG) enhances substrate binding, resulting in inhibition of the enzyme activity of FpPG. This interaction promotes FpPG-catalyzed production of long-chain immunoactive oligogalacturonides, while diminishing immunosuppressive short oligogalacturonides. PvPGIP2 binding creates a substrate binding site on PvPGIP2-FpPG, forming a new polygalacturonase with boosted substrate binding activity and altered substrate preference. Structure-based engineering converts a putative PGIP that initially lacks FpPG-binding activity into an effective FpPG-interacting protein. These findings unveil a mechanism for plants to transform pathogen virulence activity into a defense trigger and provide proof of principle for engineering PGIPs with broader specificity.


Assuntos
Fusarium , Phaseolus , Imunidade Vegetal , Proteínas de Plantas , Poligalacturonase , Fatores de Virulência , Imunidade Inata , Proteínas de Plantas/metabolismo , Poligalacturonase/metabolismo , Fatores de Virulência/metabolismo , Fusarium/imunologia , Fusarium/patogenicidade , Phaseolus/imunologia , Phaseolus/microbiologia
3.
Plant Cell Rep ; 43(2): 57, 2024 Feb 06.
Artigo em Inglês | MEDLINE | ID: mdl-38319523

RESUMO

KEY MESSAGE: Sl-lncRNA20718 acts as an eTM of Sl-miR6022 regulating its expression thereby affecting SlRLP6/10 expression. SlRLP6/10 regulate PRs expression, ROS accumulation, and JA/ET content thereby affecting tomato resistance to P. infestans. Tomato (Solanum lycopersicum) is an important horticultural and cash crop whose yield and quality can be severely affected by Phytophthora infestans (P. infestans). Long non-coding RNAs (lncRNAs) and microRNAs (miRNAs) are widely involved in plant defense responses against pathogens. The involvement of Sl-lncRNA20718 and Sl-miR6022 in tomato resistance to P. infestans as well as the targeting of Sl-miR6022 to receptor-like protein genes (RLPs) were predicted in our previous study. However, uncertainty exists regarding their potential interaction as well as the molecular processes regulating tomato resistance. Here, we found that Sl-lncRNA20718 and Sl-miR6022 are positive and negative regulators of tomato resistance to P. infestans by gain- and loss-of-function experiments, respectively. Overexpression of Sl-lncRNA20718 decreased the expression of Sl-miR6022, induced the expression of PRs, reduced the diameter of lesions (DOLs), thereby enhanced disease resistance. A six-point mutation in the binding region of Sl-lncRNA20718 to Sl-miR6022 disabled the interaction, indicating that Sl-lncRNA20718 acts as an endogenous target mimic (eTM) of Sl-miR6022. We demonstrated that Sl-miR6022 cleaves SlRLP6/10. Overexpression of Sl-miR6022 decreases the expression levels of SlRLP6/10, induces the accumulation of reactive oxygen species (ROS) and reduces the content of JA and ET, thus inhibiting tomato resistance to P. infestans. In conclusion, our study provides detailed information on the lncRNA20718-miR6022-RLPs module regulating tomato resistance to P. infestans by affecting the expression of disease resistance-related genes, the accumulation of ROS and the phytohormone levels, providing a new reference for tomato disease resistance breeding.


Assuntos
Resistência à Doença , MicroRNAs , Phytophthora infestans , RNA Longo não Codificante , Solanum lycopersicum , Resistência à Doença/genética , Phytophthora infestans/patogenicidade , Melhoramento Vegetal , Espécies Reativas de Oxigênio , Solanum lycopersicum/genética , Solanum lycopersicum/microbiologia , MicroRNAs/genética , RNA Longo não Codificante/genética , Doenças das Plantas
4.
Nature ; 626(8000): 827-835, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38355791

RESUMO

Individuals differ widely in their immune responses, with age, sex and genetic factors having major roles in this inherent variability1-6. However, the variables that drive such differences in cytokine secretion-a crucial component of the host response to immune challenges-remain poorly defined. Here we investigated 136 variables and identified smoking, cytomegalovirus latent infection and body mass index as major contributors to variability in cytokine response, with effects of comparable magnitudes with age, sex and genetics. We find that smoking influences both innate and adaptive immune responses. Notably, its effect on innate responses is quickly lost after smoking cessation and is specifically associated with plasma levels of CEACAM6, whereas its effect on adaptive responses persists long after individuals quit smoking and is associated with epigenetic memory. This is supported by the association of the past smoking effect on cytokine responses with DNA methylation at specific signal trans-activators and regulators of metabolism. Our findings identify three novel variables associated with cytokine secretion variability and reveal roles for smoking in the short- and long-term regulation of immune responses. These results have potential clinical implications for the risk of developing infections, cancers or autoimmune diseases.


Assuntos
Imunidade Adaptativa , Fumar , Feminino , Humanos , Masculino , Imunidade Adaptativa/efeitos dos fármacos , Imunidade Adaptativa/genética , Doenças Autoimunes/etiologia , Doenças Autoimunes/imunologia , Índice de Massa Corporal , Citocinas/sangue , Citocinas/imunologia , Citomegalovirus/imunologia , Citomegalovirus/patogenicidade , Citomegalovirus/fisiologia , Metilação de DNA/efeitos dos fármacos , Epigênese Genética/efeitos dos fármacos , Imunidade Inata/efeitos dos fármacos , Imunidade Inata/genética , Infecções/etiologia , Infecções/imunologia , Neoplasias/etiologia , Neoplasias/imunologia , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/imunologia , Fumar/efeitos adversos , Fumar/sangue , Fumar/genética , Fumar/imunologia
5.
J Virol ; 98(2): e0188823, 2024 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-38289104

RESUMO

Human cytomegalovirus (HCMV) utilizes peripheral blood monocytes as a means to systemically disseminate throughout the host. Following viral entry, HCMV stimulates non-canonical Akt signaling leading to the activation of mTORC1 and the subsequent translation of select antiapoptotic proteins within infected monocytes. However, the full extent to which the HCMV-initiated Akt/mTORC1 signaling axis reshapes the monocyte translatome is unclear. We found HCMV entry alone was able to stimulate widescale changes to mRNA translation levels and that inhibition of mTOR, a component of mTORC1, dramatically attenuated HCMV-induced protein synthesis. Although monocytes treated with normal myeloid growth factors also exhibited increased levels of translation, mTOR inhibition had no effect, suggesting HCMV activation of mTOR stimulates the acquisition of a unique translatome within infected monocytes. Indeed, polyribosomal profiling of HCMV-infected monocytes identified distinct prosurvival transcripts that were preferentially loaded with ribosomes when compared to growth factor-treated cells. Sirtuin 1 (SIRT1), a deacetylase that exerts prosurvival effects through regulation of the PI3K/Akt pathway, was found to be highly enriched following HCMV infection in an mTOR-dependent manner. Importantly, SIRT1 inhibition led to the death of HCMV-infected monocytes while having minimal effect on uninfected cells. SIRT1 also supported a positive feedback loop to sustain Akt/mTORC1 signaling following viral entry. Taken together, HCMV profoundly reshapes mRNA translation in an mTOR-dependent manner to enhance the synthesis of select factors necessary for the survival of infected monocytes.IMPORTANCEHuman cytomegalovirus (HCMV) infection is a significant cause of morbidity and mortality among the immunonaïve and immunocompromised. Peripheral blood monocytes are a major cell type responsible for disseminating the virus from the initial site of infection. In order for monocytes to mediate viral spread within the host, HCMV must subvert the naturally short lifespan of these cells. In this study, we performed polysomal profiling analysis, which demonstrated HCMV to globally redirect mRNA translation toward the synthesis of cellular prosurvival factors within infected monocytes. Specifically, HCMV entry into monocytes induced the translation of cellular SIRT1 to generate an antiapoptotic state. Defining the precise mechanisms through which HCMV stimulates survival will provide insight into novel anti-HCMV drugs able to target infected monocytes.


Assuntos
Citomegalovirus , Alvo Mecanístico do Complexo 1 de Rapamicina , Monócitos , Biossíntese de Proteínas , Humanos , Apoptose , Sobrevivência Celular , Citomegalovirus/crescimento & desenvolvimento , Citomegalovirus/patogenicidade , Citomegalovirus/fisiologia , Infecções por Citomegalovirus/imunologia , Infecções por Citomegalovirus/patologia , Infecções por Citomegalovirus/transmissão , Infecções por Citomegalovirus/virologia , Retroalimentação Fisiológica , Alvo Mecanístico do Complexo 1 de Rapamicina/metabolismo , Monócitos/citologia , Monócitos/metabolismo , Monócitos/virologia , Fosfatidilinositol 3-Quinases/metabolismo , Polirribossomos/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Sirtuína 1/metabolismo
6.
BMC Infect Dis ; 24(1): 112, 2024 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-38254046

RESUMO

BACKGROUND: The World Health Organization (WHO) declared Coronavirus Disease 2019 (COVID-19) a global pandemic on March 11, 2020. Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection has killed millions of people and had a terrible effect on society. The transmembrane protease serine 2 (TMPRSS2) enzyme is essential in the initial phases of the interplay between the SARSCoV-2 and the host cells by assisting viral entrance. METHODS: This observational case-control study involved 150 participants, 100 adult patients with COVID-19, 50 of whom appeared healthy and had no history of or symptoms of COVID-19 infection when the study was conducted. Between January and April 2022, patients were taken as inpatients in isolation units or through recruitment from the COVID-19 clinic at Kasr Al-Ainy Cairo University Hospitals. According to the National Institutes of Health guidelines (2021), they were categorised into three categories: mild, moderate, and severe. TMPRSS2 p.(Val197Met) variant genotyping was evaluated using TaqMan Real-Time PCR. RESULTS: The study showed a substantial difference between the mild and severe COVID-19 patient groups regarding their TMPRSS2 (p.Val197Met) genotypes (P value = 0.046). The C allele was significantly more prevalent in the mild, moderate and severe COVID-19 patient categories (77.8%, 89.7% and 91.7%, respectively) and the control group (80%). Meanwhile, the T allele was more prevalent in the mild (22.2%) and control (20%) groups. There was a statistically significant difference in allelic distribution between the mild and severe groups (P value = 0.034). CONCLUSION: The study showed a connection between the TMPRSS2 gene variant p.(Val197Met) and the degree of illness. We concluded that the T(mutant) allele was protective against severe COVID-19 because it was linked to lesser disease severity.


Assuntos
COVID-19 , Serina Endopeptidases , Adulto , Humanos , Alelos , Estudos de Casos e Controles , COVID-19/genética , Genótipo , SARS-CoV-2/patogenicidade , Serina Endopeptidases/genética , Estados Unidos
7.
J Virol ; 98(1): e0084923, 2024 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-38174935

RESUMO

Hepatitis C virus (HCV) is a member of the Flaviviridae family; however, unlike other family members, the HCV virion has an unusually high lipid content. HCV has two envelope glycoproteins, E1 and E2. E2 contributes to receptor binding, cell membrane attachment, and immune evasion. In contrast, the functions of E1 are poorly characterized due, in part, to challenges in producing the protein. This manuscript describes the expression and purification of a soluble E1 ectodomain (eE1) that is recognized by conformational, human monoclonal antibodies. eE1 forms a complex with apolipoproteins AI and AII, cholesterol, and phospholipids by recruiting high-density lipoprotein (HDL) from the extracellular media. We show that HDL binding is a function specific to eE1 and HDL hinders recognition of E1 by a neutralizing monoclonal antibody. Either low-density lipoprotein or HDL increases the production and infectivity of cell culture-produced HCV, but E1 preferentially selects HDL, influencing both viral life cycle and antibody evasion.IMPORTANCEHepatitis C virus (HCV) infection is a significant burden on human health, but vaccine candidates have yet to provide broad protection against this infection. We have developed a method to produce high quantities of soluble E1 or E2, the viral proteins located on the surface of HCV. HCV has an unusually high lipid content due to the recruitment of apolipoproteins. We found that E1 (and not E2) preferentially recruits host high-density lipoprotein (HDL) extracellularly. This recruitment of HDL by E1 prevents binding of E1 by a neutralizing antibody and furthermore prevents antibody-mediated neutralization of the virus. By comparison, low-density lipoprotein does not protect the virus from antibody-mediated neutralization. Our findings provide mechanistic insight into apolipoprotein recruitment, which may be critical for vaccine development.


Assuntos
Hepacivirus , Hepatite C , Evasão da Resposta Imune , Lipoproteínas HDL , Proteínas do Envelope Viral , Humanos , Anticorpos Monoclonais/imunologia , Anticorpos Neutralizantes/imunologia , Apolipoproteínas/metabolismo , Hepacivirus/patogenicidade , Hepatite C/imunologia , Hepatite C/virologia , Anticorpos Anti-Hepatite C/imunologia , Lipoproteínas HDL/metabolismo , Lipoproteínas LDL/metabolismo , Proteínas do Envelope Viral/metabolismo , Células HEK293
8.
Nat Microbiol ; 9(1): 95-107, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38168615

RESUMO

The host type I interferon (IFN) pathway is a major signature of inflammation induced by the human fungal pathogen, Candida albicans. However, the molecular mechanism for activating this pathway in the host defence against C. albicans remains unknown. Here we reveal that mice lacking cyclic GMP-AMP synthase (cGAS)-stimulator of IFN genes (STING) pathway components had improved survival following an intravenous challenge by C. albicans. Biofilm-associated C. albicans DNA packaged in extracellular vesicles triggers the cGAS-STING pathway as determined by induction of interferon-stimulated genes, IFNß production, and phosphorylation of IFN regulatory factor 3 and TANK-binding kinase 1. Extracellular vesicle-induced activation of type I IFNs was independent of the Dectin-1/Card9 pathway and did not require toll-like receptor 9. Single nucleotide polymorphisms in cGAS and STING potently altered inflammatory cytokine production in human monocytes challenged by C. albicans. These studies provide insights into the early innate immune response induced by a clinically significant fungal pathogen.


Assuntos
Candidíase , Interferon Tipo I , Animais , Camundongos , Candida albicans/patogenicidade , Proteínas Adaptadoras de Sinalização CARD/metabolismo , Imunidade Inata , Interferon Tipo I/metabolismo , Nucleotidiltransferases/genética , Nucleotidiltransferases/metabolismo , Transdução de Sinais , Candidíase/metabolismo , Candidíase/patologia
11.
J Agric Food Chem ; 72(2): 1025-1034, 2024 Jan 17.
Artigo em Inglês | MEDLINE | ID: mdl-38181197

RESUMO

In this study, the role of WSC1 in the infection of pear fruit by Penicillium expansum was investigated. The WSC1 gene was knocked out and complemented by Agrobacterium-mediated homologous recombination technology. Then, the changes in growth, development, and pathogenic processes of the knockout mutant and the complement mutant were analyzed. The results indicated that deletion of WSC1 slowed the growth rate, reduced the mycelial and spore yield, and reduced the ability to produce toxins and pathogenicity of P. expansum in pear fruits. At the same time, the deletion of WSC1 reduced the tolerance of P. expansum to cell wall stress factors, enhanced antioxidant capacity, decreased hypertonic sensitivity, decreased salt stress resistance, and was more sensitive to most metal ions. Our results confirmed that WSC1 plays an important role in maintaining cell wall integrity and responding to stress, toxin production, and the pathogenicity of P. expansum.


Assuntos
Patulina , Penicillium , Pyrus , Frutas , Penicillium/genética , Penicillium/patogenicidade , Virulência
14.
PLoS Negl Trop Dis ; 18(1): e0011874, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38166153

RESUMO

BACKGROUND: Proteases secreted by Trichinella spiralis intestinal infective larvae (IIL) play an important role in larval invasion and pathogenesis. However, the mechanism through which proteases mediate larval invasion of intestinal epithelial cells (IECs) remains unclear. A novel T. spiralis trypsin (TsTryp) was identified in IIL excretory/secretory (ES) proteins. It was an early and highly expressed protease at IIL stage, and had the potential as an early diagnostic antigen. The aim of this study was to investigate the biological characteristics of this novel TsTryp, its role in larval invasion of gut epithelium, and the mechanisms involved. METHODOLOGY/PRINCIPAL FINDING: TsTryp with C-terminal domain was cloned and expressed in Escherichia coli BL21 (DE3), and the rTsTryp had the enzymatic activity of natural trypsin, but it could not directly degrade gut tight junctions (TJs) proteins. qPCR and western blotting showed that TsTryp was highly expressed at the invasive IIL stage. Immunofluorescence assay (IFA), ELISA and Far Western blotting revealed that rTsTryp specifically bound to IECs, and confocal microscopy showed that the binding of rTsTryp with IECs was mainly localized in the cytomembrane. Co-immunoprecipitation (Co-IP) confirmed that rTsTryp bound to protease activated receptors 2 (PAR2) in Caco-2 cells. rTsTryp binding to PAR2 resulted in decreased expression levels of ZO-1 and occludin and increased paracellular permeability in Caco-2 monolayers by activating the extracellular regulated protein kinases 1/2 (ERK1/2) pathway. rTsTryp decreased TJs expression and increased epithelial permeability, which could be abrogated by the PAR2 antagonist AZ3451 and ERK1/2 inhibitor PD98059. rTsTryp facilitated larval invasion of IECs, and anti-rTsTryp antibodies inhibited invasion. Both inhibitors impeded larval invasion and alleviated intestinal inflammation in vitro and in vivo. CONCLUSIONS: TsTryp binding to PAR2 activated the ERK1/2 pathway, decreased the expression of gut TJs proteins, disrupted epithelial integrity and barrier function, and consequently mediated larval invasion of the gut mucosa. Therefore, rTsTryp could be regarded as a potential vaccine target for blocking T. spiralis invasion and infection.


Assuntos
Receptor PAR-2 , Trichinella spiralis , Triquinelose , Animais , Humanos , Camundongos , Células CACO-2 , Epitélio/metabolismo , Proteínas de Helminto/metabolismo , Larva/fisiologia , Sistema de Sinalização das MAP Quinases , Camundongos Endogâmicos BALB C , Proteínas Quinases , Trichinella spiralis/metabolismo , Trichinella spiralis/patogenicidade , Triquinelose/genética , Triquinelose/metabolismo , Tripsina/metabolismo , Receptor PAR-2/metabolismo
15.
Cell ; 187(3): 596-608.e17, 2024 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-38194966

RESUMO

BA.2.86, a recently identified descendant of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron BA.2 sublineage, contains ∼35 mutations in the spike (S) protein and spreads in multiple countries. Here, we investigated whether the virus exhibits altered biological traits, focusing on S protein-driven viral entry. Employing pseudotyped particles, we show that BA.2.86, unlike other Omicron sublineages, enters Calu-3 lung cells with high efficiency and in a serine- but not cysteine-protease-dependent manner. Robust lung cell infection was confirmed with authentic BA.2.86, but the virus exhibited low specific infectivity. Further, BA.2.86 was highly resistant against all therapeutic antibodies tested, efficiently evading neutralization by antibodies induced by non-adapted vaccines. In contrast, BA.2.86 and the currently circulating EG.5.1 sublineage were appreciably neutralized by antibodies induced by the XBB.1.5-adapted vaccine. Collectively, BA.2.86 has regained a trait characteristic of early SARS-CoV-2 lineages, robust lung cell entry, and evades neutralizing antibodies. However, BA.2.86 exhibits low specific infectivity, which might limit transmissibility.


Assuntos
Anticorpos Neutralizantes , Anticorpos Antivirais , COVID-19 , SARS-CoV-2 , Humanos , Anticorpos Neutralizantes/metabolismo , Anticorpos Antivirais/metabolismo , Caspases/metabolismo , COVID-19/imunologia , COVID-19/virologia , Pulmão/virologia , SARS-CoV-2/classificação , SARS-CoV-2/genética , SARS-CoV-2/patogenicidade , SARS-CoV-2/fisiologia , Internalização do Vírus , Glicoproteína da Espícula de Coronavírus/genética
17.
J Mol Biol ; 436(4): 168415, 2024 02 15.
Artigo em Inglês | MEDLINE | ID: mdl-38135177

RESUMO

Staphylococcus aureus is an important human pathogen, and the prevalence of antibiotic resistance is a major public health concern. The evolution of pathogenicity and resistance in S. aureus often involves acquisition of mobile genetic elements (MGEs). Bacteriophages play an especially important role, since transduction represents the main mechanism for horizontal gene transfer. S. aureus pathogenicity islands (SaPIs), including SaPI1, are MGEs that carry genes encoding virulence factors, and are mobilized at high frequency through interactions with specific "helper" bacteriophages, such as 80α, leading to packaging of the SaPI genomes into virions made from structural proteins supplied by the helper. Among these structural proteins is the portal protein, which forms a ring-like portal at a fivefold vertex of the capsid, through which the DNA is packaged during virion assembly and ejected upon infection of the host. We have used high-resolution cryo-electron microscopy to determine structures of the S. aureus bacteriophage 80α portal itself, produced by overexpression, and in situ in the empty and full SaPI1 virions, and show how the portal interacts with the capsid. These structures provide a basis for understanding portal and capsid assembly and the conformational changes that occur upon DNA packaging and ejection.


Assuntos
Ilhas Genômicas , Fagos de Staphylococcus , Staphylococcus aureus , Humanos , Proteínas do Capsídeo/química , Microscopia Crioeletrônica , Staphylococcus aureus/genética , Staphylococcus aureus/patogenicidade , Staphylococcus aureus/virologia , Fagos de Staphylococcus/genética , Fatores de Virulência/genética , Transdução Genética , Empacotamento do DNA , Conformação de Ácido Nucleico
18.
J Biol Chem ; 300(1): 105577, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38110035

RESUMO

Harvester ants (genus Pogonomyrmex) are renowned for their stings which cause intense, long-lasting pain, and other neurotoxic symptoms in vertebrates. Here, we show that harvester ant venoms are relatively simple and composed largely of peptide toxins. One class of peptides is primarily responsible for the long-lasting local pain of envenomation via activation of peripheral sensory neurons. These hydrophobic, cysteine-free peptides potently modulate mammalian voltage-gated sodium (NaV) channels, reducing the voltage threshold for activation and inhibiting channel inactivation. These toxins appear to have evolved specifically to deter vertebrates.


Assuntos
Formigas , Mordeduras e Picadas , Dor , Peptídeos , Toxinas Biológicas , Bloqueadores do Canal de Sódio Disparado por Voltagem , Canais de Sódio Disparados por Voltagem , Animais , Formigas/patogenicidade , Formigas/fisiologia , Mordeduras e Picadas/complicações , Dor/induzido quimicamente , Dor/complicações , Peptídeos/química , Peptídeos/farmacologia , Peptídeos/toxicidade , Células Receptoras Sensoriais/efeitos dos fármacos , Células Receptoras Sensoriais/fisiologia , Toxinas Biológicas/química , Toxinas Biológicas/farmacologia , Toxinas Biológicas/toxicidade , Vertebrados , Bloqueadores do Canal de Sódio Disparado por Voltagem/química , Bloqueadores do Canal de Sódio Disparado por Voltagem/farmacologia , Bloqueadores do Canal de Sódio Disparado por Voltagem/toxicidade , Canais de Sódio Disparados por Voltagem/metabolismo
19.
Nature ; 625(7995): 578-584, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38123677

RESUMO

The symptoms of malaria occur during the blood stage of infection, when parasites invade and replicate within human erythrocytes. The PfPCRCR complex1, containing PfRH5 (refs. 2,3), PfCyRPA, PfRIPR, PfCSS and PfPTRAMP, is essential for erythrocyte invasion by the deadliest human malaria parasite, Plasmodium falciparum. Invasion can be prevented by antibodies3-6 or nanobodies1 against each of these conserved proteins, making them the leading blood-stage malaria vaccine candidates. However, little is known about how PfPCRCR functions during invasion. Here we present the structure of the PfRCR complex7,8, containing PfRH5, PfCyRPA and PfRIPR, determined by cryogenic-electron microscopy. We test the hypothesis that PfRH5 opens to insert into the membrane9, instead showing that a rigid, disulfide-locked PfRH5 can mediate efficient erythrocyte invasion. We show, through modelling and an erythrocyte-binding assay, that PfCyRPA-binding antibodies5 neutralize invasion through a steric mechanism. We determine the structure of PfRIPR, showing that it consists of an ordered, multidomain core flexibly linked to an elongated tail. We also show that the elongated tail of PfRIPR, which is the target of growth-neutralizing antibodies6, binds to the PfCSS-PfPTRAMP complex on the parasite membrane. A modular PfRIPR is therefore linked to the merozoite membrane through an elongated tail, and its structured core presents PfCyRPA and PfRH5 to interact with erythrocyte receptors. This provides fresh insight into the molecular mechanism of erythrocyte invasion and opens the way to new approaches in rational vaccine design.


Assuntos
Eritrócitos , Malária Falciparum , Complexos Multiproteicos , Parasitos , Plasmodium falciparum , Proteínas de Protozoários , Animais , Humanos , Anticorpos Neutralizantes/imunologia , Antígenos de Protozoários/química , Antígenos de Protozoários/imunologia , Microscopia Crioeletrônica , Dissulfetos/química , Dissulfetos/metabolismo , Eritrócitos/metabolismo , Eritrócitos/parasitologia , Vacinas Antimaláricas/imunologia , Malária Falciparum/imunologia , Malária Falciparum/metabolismo , Malária Falciparum/parasitologia , Malária Falciparum/patologia , Merozoítos/metabolismo , Complexos Multiproteicos/química , Complexos Multiproteicos/imunologia , Complexos Multiproteicos/metabolismo , Complexos Multiproteicos/ultraestrutura , Parasitos/metabolismo , Parasitos/patogenicidade , Plasmodium falciparum/metabolismo , Plasmodium falciparum/patogenicidade , Proteínas de Protozoários/química , Proteínas de Protozoários/imunologia , Proteínas de Protozoários/metabolismo , Proteínas de Protozoários/ultraestrutura
20.
Nucleic Acids Res ; 52(3): 1226-1242, 2024 Feb 09.
Artigo em Inglês | MEDLINE | ID: mdl-38142443

RESUMO

Transposable elements (TEs) are key drivers of genomic variation contributing to recent adaptation in most species. Yet, the evolutionary origins and insertion dynamics within species remain poorly understood. We recapitulate the spread of the pathogenicity-associated Styx element across five species that last diverged ∼11 000 years ago. We show that the element likely originated in the Zymoseptoria fungal pathogen genus and underwent multiple independent reactivation events. Using a global 900-genome panel of the wheat pathogen Zymoseptoria tritici, we assess Styx copy number variation and identify renewed transposition activity in Oceania and South America. We show that the element can mobilize to create additional Styx copies in a four-generation pedigree. Importantly, we find that new copies of the element are not affected by genomic defenses suggesting minimal control against the element. Styx copies are preferentially located in recombination breakpoints and likely triggered multiple types of large chromosomal rearrangements. Taken together, we establish the origin, diversification and reactivation of a highly active TE with likely major consequences for chromosomal integrity and the expression of disease.


Assuntos
Ascomicetos , Variações do Número de Cópias de DNA , Elementos de DNA Transponíveis , Humanos , Evolução Biológica , Aberrações Cromossômicas , Cromossomos , Evolução Molecular , Virulência , Ascomicetos/genética , Ascomicetos/patogenicidade , Ascomicetos/fisiologia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...