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1.
Nat Commun ; 11(1): 4471, 2020 09 08.
Artigo em Inglês | MEDLINE | ID: mdl-32901010

RESUMO

A human cell contains hundreds to thousands of mitochondrial DNA (mtDNA) packaged into nucleoids. Currently, the segregation and allocation of nucleoids are thought to be passively determined by mitochondrial fusion and division. Here we provide evidence, using live-cell super-resolution imaging, that nucleoids can be actively transported via KIF5B-driven mitochondrial dynamic tubulation (MDT) activities that predominantly occur at the ER-mitochondria contact sites (EMCS). We further demonstrate that a mitochondrial inner membrane protein complex MICOS links nucleoids to Miro1, a KIF5B receptor on mitochondria, at the EMCS. We show that such active transportation is a mechanism essential for the proper distribution of nucleoids in the peripheral zone of the cell. Together, our work identifies an active transportation mechanism of nucleoids, with EMCS serving as a key platform for the interplay of nucleoids, MICOS, Miro1, and KIF5B to coordinate nucleoids segregation and transportation.


Assuntos
DNA Mitocondrial/metabolismo , Retículo Endoplasmático/metabolismo , Mitocôndrias/metabolismo , Dinâmica Mitocondrial/fisiologia , Animais , Transporte Biológico Ativo , Células COS , Células Cultivadas , Chlorocebus aethiops , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Células HEK293 , Humanos , Cinesina/metabolismo , Proteínas de Membrana Transportadoras/genética , Proteínas de Membrana Transportadoras/metabolismo , Camundongos , Membranas Mitocondriais/metabolismo , Proteínas Mitocondriais/genética , Proteínas Mitocondriais/metabolismo , Modelos Biológicos , Ratos , Receptores de Superfície Celular/genética , Receptores de Superfície Celular/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Transfecção , Proteínas rho de Ligação ao GTP/metabolismo
2.
Genes (Basel) ; 11(9)2020 09 03.
Artigo em Inglês | MEDLINE | ID: mdl-32899439

RESUMO

The importance of host genetics and demography in coronavirus disease 2019 (COVID-19) is a crucial aspect of infection, prognosis and associated case fatality rate. Individual genetic landscapes can contribute to understand Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) burden and can give information on how to fight virus spreading and the associated severe acute respiratory distress syndrome (ARDS). The spread and pathogenicity of the virus have become pandemic on specific geographic areas and ethnicities. Interestingly, SARS-CoV-2 firstly emerged in East Asia and next in Europe, where it has caused higher morbidity and mortality. This is a peculiar feature of SARS-CoV-2, different from past global viral infections (i.e., SARS-1 or MERS); it shares with the previous pandemics strong age- and sex-dependent gaps in the disease outcome. The observation that the severest COVID-19 patients are more likely to have a history of hypertension, diabetes and/or cardiovascular disease and receive Renin-Angiotensin-System (RAS) inhibitor treatment raised the hypothesis that RAS-unbalancing may have a crucial role. Accordingly, we recently published a genetic hypothesis on the role of RAS-pathway genes (ACE1, rs4646994, rs1799752, rs4340, rs13447447; and ACE2, rs2285666, rs1978124, rs714205) and ABO-locus (rs495828, rs8176746) in COVID-19 prognosis, suspecting inherited genetic predispositions to be predictive of COVID-19 severity. In addition, recently, Genome-Wide Association Studies (GWAS) found COVID-19-association signals at locus 3p21.31 (rs11385942) comprising the solute carrier SLC6A20 (Na+ and Cl- coupled transporter family) and at locus 9q34.2 (rs657152) coincident with ABO-blood group (rs8176747, rs41302905, rs8176719), and interestingly, both loci are associated to RAS-pathway. Finally, ACE1 and ACE2 haplotypes seem to provide plausible explanations for why SARS-CoV-2 have affected more heavily some ethnic groups, namely people with European ancestry, than Asians.


Assuntos
Infecções por Coronavirus/patologia , Pneumonia Viral/patologia , Sistema Renina-Angiotensina/genética , Sistema ABO de Grupos Sanguíneos/genética , Betacoronavirus/isolamento & purificação , Infecções por Coronavirus/virologia , Haplótipos , Humanos , Proteínas de Membrana Transportadoras/genética , Pandemias , Peptidil Dipeptidase A/genética , Peptidil Dipeptidase A/metabolismo , Pneumonia Viral/virologia , Polimorfismo Genético , Prognóstico , Caracteres Sexuais
3.
Nat Commun ; 11(1): 4837, 2020 09 24.
Artigo em Inglês | MEDLINE | ID: mdl-32973183

RESUMO

ATP synthesis and thermogenesis are two critical outputs of mitochondrial respiration. How these outputs are regulated to balance the cellular requirement for energy and heat is largely unknown. Here we show that major facilitator superfamily domain containing 7C (MFSD7C) uncouples mitochondrial respiration to switch ATP synthesis to thermogenesis in response to heme. When heme levels are low, MSFD7C promotes ATP synthesis by interacting with components of the electron transport chain (ETC) complexes III, IV, and V, and destabilizing sarcoendoplasmic reticulum Ca2+-ATPase 2b (SERCA2b). Upon heme binding to the N-terminal domain, MFSD7C dissociates from ETC components and SERCA2b, resulting in SERCA2b stabilization and thermogenesis. The heme-regulated switch between ATP synthesis and thermogenesis enables cells to match outputs of mitochondrial respiration to their metabolic state and nutrient supply, and represents a cell intrinsic mechanism to regulate mitochondrial energy metabolism.


Assuntos
Trifosfato de Adenosina/metabolismo , Heme/metabolismo , Proteínas de Membrana Transportadoras/metabolismo , Mitocôndrias/metabolismo , Receptores Virais/metabolismo , Termogênese/fisiologia , Animais , Deficiência de Citocromo-c Oxidase , Complexo III da Cadeia de Transporte de Elétrons , Complexo IV da Cadeia de Transporte de Elétrons , Metabolismo Energético/fisiologia , Técnicas de Inativação de Genes , Células HEK293 , Humanos , Proteínas de Membrana Transportadoras/genética , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Membranas Mitocondriais/metabolismo , Domínios Proteicos , Receptores Virais/genética , ATPases Transportadoras de Cálcio do Retículo Sarcoplasmático/metabolismo , Transdução de Sinais , Células THP-1
4.
PLoS One ; 15(8): e0237457, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32780764

RESUMO

Onion (Allium cepa L.) is an important vegetable crop widely grown for diverse culinary and nutraceutical properties. Being a shallow-rooted plant, it is prone to drought. In the present study, transcriptome sequencing of drought-tolerant (1656) and drought-sensitive (1627) onion genotypes was performed to elucidate the molecular basis of differential response to drought stress. A total of 123206 and 139252 transcripts (average transcript length: 690 bases) were generated after assembly for 1656 and 1627, respectively. Differential gene expression analyses revealed upregulation and downregulation of 1189 and 1180 genes, respectively, in 1656, whereas in 1627, upregulation and downregulation of 872 and 1292 genes, respectively, was observed. Genes encoding transcription factors, cytochrome P450, membrane transporters, and flavonoids, and those related to carbohydrate metabolism were found to exhibit a differential expression behavior in the tolerant and susceptible genotypes. The information generated can facilitate a better understanding of molecular mechanisms underlying drought response in onion.


Assuntos
Secas , Regulação da Expressão Gênica de Plantas , Cebolas/genética , Metabolismo dos Carboidratos/genética , Perfilação da Expressão Gênica/métodos , Genótipo , Proteínas de Membrana Transportadoras/genética , RNA de Plantas/química , RNA de Plantas/metabolismo , Fatores de Transcrição/genética
5.
PLoS One ; 15(8): e0237474, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32857767

RESUMO

The effective treatment of carbapenemase-producing Klebsiella pneumoniae infection has been limited and required novel potential agents. Due to the novel drug development crisis, using old antimicrobial agents and combination therapy have been highlighted. This study focused on fosfomycin which inhibits cell wall synthesis and has potential activity on Enterobacteriaceae. We evaluated fosfomycin activity against carbapenemase-producing K. pneumoniae and characterized fosfomycin resistance mechanisms. Fosfomycin revealed effective activity against only 31.8% of carbapenemase-producing K. pneumoniae isolates. The major resistance mechanism was FosA3 production. The co-occurrence of FosA3 overexpression with the mutation of glpT (or loss of glpT) and/or uhpT was mediated high-level resistance (MIC>256 mg/L) to fosfomycin. Moreover, fosA3 silenced in sixteen fosfomycin-susceptible isolates and the plasmid carrying fosA3 of these isolates increased 32- to 64-fold of fosfomycin MICs in Escherichia coli DH5α transformants. The in vitro activity of fosfomycin combination with amikacin by checkerboard assay showed synergism and no interaction in six (16.2%) and sixteen isolates (43.3%), respectively. No antagonism of fosfomycin and amikacin was observed. Notably, the silence of aac (6)'-Ib and aphA6 was observed in amikacin-susceptible isolates. Our study suggests that the combination of fosfomycin and amikacin may be insufficient for the treatment of carbapenemase-producing K. pneumoniae isolates.


Assuntos
Antibacterianos/farmacologia , Proteínas de Bactérias/metabolismo , Farmacorresistência Bacteriana/genética , Fosfomicina/farmacologia , Klebsiella pneumoniae/efeitos dos fármacos , beta-Lactamases/metabolismo , Amicacina/farmacologia , Substituição de Aminoácidos , Proteínas de Bactérias/antagonistas & inibidores , Proteínas de Bactérias/genética , Escherichia coli/metabolismo , Humanos , Infecções por Klebsiella/microbiologia , Infecções por Klebsiella/patologia , Klebsiella pneumoniae/enzimologia , Klebsiella pneumoniae/isolamento & purificação , Proteínas de Membrana Transportadoras/genética , Proteínas de Membrana Transportadoras/metabolismo , Testes de Sensibilidade Microbiana , Plasmídeos/genética , Plasmídeos/metabolismo , RNA Mensageiro/metabolismo , beta-Lactamases/genética
6.
PLoS Biol ; 18(8): e3000790, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32776918

RESUMO

Concentrative nucleoside transporters (CNTs), members of the solute carrier (SLC) 28 transporter family, facilitate the salvage of nucleosides and therapeutic nucleoside derivatives across the plasma membrane. Despite decades of investigation, the structures of human CNTs remain unknown. We determined the cryogenic electron microscopy (cryo-EM) structure of human CNT (hCNT) 3 at an overall resolution of 3.6 Å. As with its bacterial homologs, hCNT3 presents a trimeric architecture with additional N-terminal transmembrane helices to stabilize the conserved central domains. The conserved binding sites for the substrate and sodium ions unravel the selective nucleoside transport and distinct coupling mechanism. Structural comparison of hCNT3 with bacterial homologs indicates that hCNT3 is stabilized in an inward-facing conformation. This study provides the molecular determinants for the transport mechanism of hCNTs and potentially facilitates the design of nucleoside drugs.


Assuntos
Proteínas de Bactérias/química , Proteínas de Membrana Transportadoras/química , Uridina/química , Animais , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Baculoviridae/genética , Baculoviridae/metabolismo , Sítios de Ligação , Transporte Biológico , Clonagem Molecular , Microscopia Crioeletrônica , Expressão Gênica , Vetores Genéticos/química , Vetores Genéticos/metabolismo , Humanos , Proteínas de Membrana Transportadoras/genética , Proteínas de Membrana Transportadoras/metabolismo , Modelos Moleculares , Ligação Proteica , Conformação Proteica em alfa-Hélice , Domínios e Motivos de Interação entre Proteínas , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Células Sf9 , Spodoptera , Homologia Estrutural de Proteína , Especificidade por Substrato , Uridina/metabolismo
7.
Nat Commun ; 11(1): 3922, 2020 08 06.
Artigo em Inglês | MEDLINE | ID: mdl-32764664

RESUMO

The Plasmodium falciparum chloroquine resistance transporter (PfCRT) is a key contributor to multidrug resistance and is also essential for the survival of the malaria parasite, yet its natural function remains unresolved. We identify host-derived peptides of 4-11 residues, varying in both charge and composition, as the substrates of PfCRT in vitro and in situ, and show that PfCRT does not mediate the non-specific transport of other metabolites and/or ions. We find that drug-resistance-conferring mutations reduce both the peptide transport capacity and substrate range of PfCRT, explaining the impaired fitness of drug-resistant parasites. Our results indicate that PfCRT transports peptides from the lumen of the parasite's digestive vacuole to the cytosol, thereby providing a source of amino acids for parasite metabolism and preventing osmotic stress of this organelle. The resolution of PfCRT's native substrates will aid the development of drugs that target PfCRT and/or restore the efficacy of existing antimalarials.


Assuntos
Antimaláricos/farmacologia , Cloroquina/farmacologia , Proteínas de Membrana Transportadoras/metabolismo , Plasmodium falciparum/efeitos dos fármacos , Plasmodium falciparum/metabolismo , Proteínas de Protozoários/metabolismo , Animais , Transporte Biológico Ativo , Resistência a Medicamentos/genética , Feminino , Interações Hospedeiro-Parasita/genética , Interações Hospedeiro-Parasita/fisiologia , Humanos , Malária Falciparum/tratamento farmacológico , Malária Falciparum/metabolismo , Malária Falciparum/parasitologia , Proteínas de Membrana Transportadoras/genética , Modelos Biológicos , Proteínas Mutantes/genética , Proteínas Mutantes/metabolismo , Oligopeptídeos/metabolismo , Oócitos/metabolismo , Plasmodium falciparum/genética , Transporte Proteico , Proteínas de Protozoários/genética , Xenopus laevis
8.
DNA Cell Biol ; 39(9): 1595-1605, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32783661

RESUMO

Autophagy, a highly conserved cellular protein degradation process, has been involved in acute myeloid leukemia (AML). The present study aims to establish a novel, autophagy-related prognostic signature for prediction of AML prognosis. Differentially expressed autophagy-related genes in AML and healthy samples were screened using GSE1159. Univariate Cox regression analysis was applied to determine survival-associated autophagy-related genes in The Cancer Genome Atlas (TCGA) AML cohort. Lasso regression was performed to develop multiple-gene prognostic signatures. A novel six-gene signature (including CASP3, CHAF1B, KLHL24, OPTN, VEGFA, and VPS37C) DC was established for AML prognosis prediction. The Kaplan-Meier survival analysis revealed that patients in the high-risk score group had poorer overall survival (OS). The receiver operating characteristic (ROC) curve validated its good performance in survival prediction in TCGA AML cohort, and the area under the curve value was 0.817. Moreover, our signature could independently predict OS. A nomogram was constructed, including the six-gene signature and other clinical parameters, and predictive efficiency was confirmed using the ROC curve and calibration curve. Furthermore, gene set enrichment analyses identified several tumor-associated pathways that may contribute to explain the potential molecular mechanisms of our signature. Overall, we developed a new autophagy-associated gene signature and nomogram to predict OS of AML patients, which may help in clinical decision-making for AML treatment.


Assuntos
Autofagia , Biomarcadores Tumorais/genética , Leucemia Mieloide Aguda/genética , Transcriptoma , Biomarcadores Tumorais/metabolismo , Caspase 3/genética , Caspase 3/metabolismo , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Fator 1 de Modelagem da Cromatina/genética , Fator 1 de Modelagem da Cromatina/metabolismo , Complexos Endossomais de Distribuição Requeridos para Transporte/genética , Complexos Endossomais de Distribuição Requeridos para Transporte/metabolismo , Humanos , Leucemia Mieloide Aguda/patologia , Proteínas de Membrana Transportadoras/genética , Proteínas de Membrana Transportadoras/metabolismo , Proteínas Repressoras/genética , Proteínas Repressoras/metabolismo , Fator A de Crescimento do Endotélio Vascular/genética , Fator A de Crescimento do Endotélio Vascular/metabolismo
9.
PLoS Genet ; 16(8): e1008966, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32776922

RESUMO

The vacuole of the yeast Saccharomyces cerevisiae plays an important role in nutrient storage. Arginine, in particular, accumulates in the vacuole of nitrogen-replete cells and is mobilized to the cytosol under nitrogen starvation. The arginine import and export systems involved remain poorly characterized, however. Furthermore, how their activity is coordinated by nitrogen remains unknown. Here we characterize Vsb1 as a novel vacuolar membrane protein of the APC (amino acid-polyamine-organocation) transporter superfamily which, in nitrogen-replete cells, is essential to active uptake and storage of arginine into the vacuole. A shift to nitrogen starvation causes apparent inhibition of Vsb1-dependent activity and mobilization of stored vacuolar arginine to the cytosol. We further show that this arginine export involves Ypq2, a vacuolar protein homologous to the human lysosomal cationic amino acid exporter PQLC2 and whose activity is detected only in nitrogen-starved cells. Our study unravels the main arginine import and export systems of the yeast vacuole and suggests that they are inversely regulated by nitrogen.


Assuntos
Arginina/metabolismo , Nitrogênio/metabolismo , Proteínas de Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/genética , Aminoácidos/genética , Transporte Biológico/genética , Humanos , Membranas Intracelulares/metabolismo , Lisossomos/genética , Proteínas de Membrana Transportadoras/genética , Proteínas de Membrana Transportadoras/metabolismo , Saccharomyces cerevisiae/metabolismo , Vacúolos/genética , Vacúolos/metabolismo
10.
PLoS One ; 15(8): e0235401, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32817665

RESUMO

BACKGROUND: Current malaria control and elimination strategies rely mainly on efficacious antimalarial drugs. However, drug resistance is a major threat facing malaria control programs. Determination of drug resistance molecular markers is useful in the monitoring and surveillance of malaria drug efficacy. This study aimed to determine the mutations and haplotypes frequencies of different genes linked with antimalarial drug resistance in certain areas in Sudan. METHODS: A total of 226 dried blood spots (DBS) of microscopically diagnosed P. falciparum isolates were collected from Khartoum and three other areas in Sudan during 2015-2017. Plasmodium falciparum confirmation and multiplicity of infection was assessed using the Sanger's 101 SNPs-barcode and speciation was confirmed using regions of the parasite mitochondria. Molecular genotyping of drug resistance genes (Pfcrt, Pfmdr1, Pfdhfr, Pfdhps, exonuclease, Pfk13, parasite genetic background (PGB) (Pfarps10, ferredoxin, Pfcrt, Pfmdr2)) was also performed. All genotypes were generated by selective regions amplicon sequencing of the parasite genome using the Illumina MiSeq platform at the Wellcome Sanger Institute, UK then genotypes were translated into drug resistance haplotypes and species determination. FINDINGS: In total 225 samples were confirmed to be P. falciparum. A higher proportion of multiplicity of infection was observed in Gezira (P<0.001) based on the Sanger 101 SNPs -barcode. The overall frequency of mutant haplotype Pfcrt 72-76 CVIET was 71.8%. For Pfmdr1, N86Y was detected in 53.6%, Y184F was observed in 88.1% and D1246Y was detected in 1.5% of the samples. The most frequently observed haplotype was YFD 47.4%. For Pfdhfr (codons 51, 59,108,164), the ICNI haplotype was the most frequent (80.7%) while for Pfdhps (codons 436, 437, 540, 581, 613) the (SGEAA) was most frequent haplotype (41%). The Quadruple mutation (dhfr N51I, S108N + dhps A437G, K540E) was the highest frequent combined mutation (33.9%). In Pfkelch13 gene, 18 non-synonymous mutations were detected, 7 of them were detected in other African countries. The most frequent Pfk13 mutation was E433D detected in four samples. All of the Pfk13 mutant alleles have not been reported to belong to mutations associated with delayed parasite clearance in Southeast Asia. PGB mutations were detected only in Pfcrt N326S\I (46.3%) and Pfcrt I356T (8.2%). The exonuclease mutation was not detected. There was no significant variation in mutant haplotypes between study areas. CONCLUSIONS: There was high frequency of mutations in Pfcrt, Pfdhfr and Pfdhps in this study. These mutations are associated with chloroquine and sulfadoxine-pyrimethamine (SP) resistance. Many SNPs in Pfk13 not linked with delayed parasite clearance were observed. The exonuclease E415G mutation which is linked with piperaquine resistance was not reported.


Assuntos
Resistência a Medicamentos/genética , Malária/parasitologia , Mutação , Plasmodium falciparum/genética , Adolescente , Antimaláricos/farmacologia , Criança , Cloroquina/farmacologia , Feminino , Humanos , Malária/epidemiologia , Masculino , Proteínas de Membrana Transportadoras/genética , Proteínas de Membrana Transportadoras/metabolismo , Plasmodium falciparum/efeitos dos fármacos , Plasmodium falciparum/patogenicidade , Proteínas de Protozoários/genética , Proteínas de Protozoários/metabolismo , Pirimetamina/farmacologia , Sudão , Sulfadoxina/farmacologia , Tetra-Hidrofolato Desidrogenase/genética , Tetra-Hidrofolato Desidrogenase/metabolismo , Adulto Jovem
11.
PLoS One ; 15(7): e0236100, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32702020

RESUMO

Feed constitutes 50-70% of total production costs of tilapia, one of the most widely cultured finfishes in the world. We evaluated reduced-feeding strategies for improving production efficiency of Nile tilapia (Oreochromis niloticus). In a 12-week pond trial, fish were fed daily, every other day, every third day, or not at all. Ponds were fertilized to enhance natural foods. In a fifth group fish were fed daily without pond fertilization. Fish fed daily with or without pond fertilization and fish fed every other day had higher specific growth rates, survivability, and net production than the other two treatments. Fish feed efficiency and benefit to cost ratio was highest for treatments fed in a pulsatile manner (i.e. fed every other day or every third day) with fish fed on alternate days providing the best net return among all groups. Fish fed on alternate days had more moderate gene expression levels of intestinal nutrient transporters which may allow for a more balanced and efficient nutrient uptake. Fecal microbe analyses identified 145 families of prokaryotic and 132 genera of eukaryotic organisms in tilapia. The highest diversity of prokaryotes was found in fish fed either every other day or daily in fertilized ponds and the highest diversity of eukaryotes was found in fish fed every other day. These studies indicate feeding Nile tilapia on alternate days along with weekly pond fertilization has no deleterious effects on growth, survivability, or production versus daily feeding regimes, but enhances feed efficiency by 76% and provides the greatest net return on investments. Our studies also suggest for the first time that combining alternate-day feeding with pond fertilization produces the greatest microbial biodiversity in the intestine that could contribute to enhanced feed efficiency and overall health of tilapia.


Assuntos
Ração Animal , Aquicultura , Biodiversidade , Microbioma Gastrointestinal , Tilápia/crescimento & desenvolvimento , Tilápia/microbiologia , Animais , Regulação da Expressão Gênica , Proteínas de Membrana Transportadoras/genética , Nutrientes/metabolismo , Tilápia/genética
12.
PLoS One ; 15(7): e0236520, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32730286

RESUMO

In eukaryotic cells, phospholipid flippases translocate phospholipids from the exoplasmic to the cytoplasmic leaflet of the lipid bilayer. Budding yeast contains five flippases, of which Cdc50p-Drs2p and Neo1p are primarily involved in membrane trafficking in endosomes and Golgi membranes. The ANY1/CFS1 gene was identified as a suppressor of growth defects in the neo1Δ and cdc50Δ mutants. Cfs1p is a membrane protein of the PQ-loop family and is localized to endosomal/Golgi membranes, but its relationship to phospholipid asymmetry remains unknown. The neo1Δ cfs1Δ mutant appears to function normally in membrane trafficking but may function abnormally in the regulation of phospholipid asymmetry. To identify a gene that is functionally relevant to NEO1 and CFS1, we isolated a mutation that is synthetically lethal with neo1Δ cfs1Δ and identified ERD1. Erd1p is a Golgi membrane protein that is involved in the transport of phosphate (Pi) from the Golgi lumen to the cytoplasm. The Neo1p-depleted cfs1Δ erd1Δ mutant accumulated plasma membrane proteins in the Golgi, perhaps due to a lack of phosphatidylinositol 4-phosphate. The Neo1p-depleted cfs1Δ erd1Δ mutant also exhibited abnormal structure of the endoplasmic reticulum (ER) and induced an unfolded protein response, likely due to defects in the retrieval pathway from the cis-Golgi region to the ER. Genetic analyses suggest that accumulation of Pi in the Golgi lumen is responsible for defects in Golgi functions in the Neo1p-depleted cfs1Δ erd1Δ mutant. Thus, the luminal ionic environment is functionally relevant to phospholipid asymmetry. Our results suggest that flippase-mediated phospholipid redistribution and luminal Pi concentration coordinately regulate Golgi membrane functions.


Assuntos
Complexo de Golgi/metabolismo , Fosfatos/metabolismo , Fosfolipídeos/metabolismo , Saccharomyces cerevisiae/genética , Adenosina Trifosfatases/genética , Retículo Endoplasmático/metabolismo , Proteínas de Membrana/genética , Proteínas de Membrana Transportadoras/genética , Mutação , Proteínas de Transferência de Fosfolipídeos/genética , Receptores Citoplasmáticos e Nucleares/genética , Saccharomyces cerevisiae/enzimologia , Proteínas de Saccharomyces cerevisiae/genética , Resposta a Proteínas não Dobradas
13.
Nat Commun ; 11(1): 3479, 2020 07 13.
Artigo em Inglês | MEDLINE | ID: mdl-32661250

RESUMO

Genetic factors contribute to the risk of thrombotic diseases. Recent genome wide association studies have identified genetic loci including SLC44A2 which may regulate thrombosis. Here we show that Slc44a2 controls platelet activation and thrombosis by regulating mitochondrial energetics. We find that Slc44a2 null mice (Slc44a2(KO)) have increased bleeding times and delayed thrombosis compared to wild-type (Slc44a2(WT)) controls. Platelets from Slc44a2(KO) mice have impaired activation in response to thrombin. We discover that Slc44a2 mediates choline transport into mitochondria, where choline metabolism leads to an increase in mitochondrial oxygen consumption and ATP production. Platelets lacking Slc44a2 contain less ATP at rest, release less ATP when activated, and have an activation defect that can be rescued by exogenous ADP. Taken together, our data suggest that mitochondria require choline for maximum function, demonstrate the importance of mitochondrial metabolism to platelet activation, and reveal a mechanism by which Slc44a2 influences thrombosis.


Assuntos
Proteínas de Membrana Transportadoras/metabolismo , Mitocôndrias/metabolismo , Ativação Plaquetária/fisiologia , Trombose/metabolismo , Trifosfato de Adenosina/metabolismo , Animais , Western Blotting , Modelos Animais de Doenças , Estudo de Associação Genômica Ampla , Masculino , Espectrometria de Massas , Proteínas de Membrana Transportadoras/genética , Camundongos , Camundongos Knockout , Mitocôndrias/genética , Ativação Plaquetária/genética , Agregação Plaquetária/genética , Agregação Plaquetária/fisiologia , Reação em Cadeia da Polimerase em Tempo Real , Trombose/genética
14.
BMC Infect Dis ; 20(1): 533, 2020 Jul 22.
Artigo em Inglês | MEDLINE | ID: mdl-32698879

RESUMO

BACKGROUND: Plasmodium falciparum parasites, which could harbour anti-malaria drug resistance genes, are commonly detected in blood donors in malaria-endemic areas. Notwithstanding, anti-malaria drug resistant biomarkers have not been characterized in blood donors with asymptomatic P. falciparum infection. METHODS: A total of 771 blood donors were selected from five districts in the Greater Accra Region, Ghana. Each donor sample was screened with malaria rapid diagnostic test (RDT) kit and parasitaemia quantified microscopically. Dried blood spots from malaria positive samples were genotyped for P. falciparum chloroquine resistance transporter (Pfcrt), P. falciparum multi-drug resistance (Pfmdr1), P. falciparum dihydropteroate-synthetase (Pfdhps), P. falciparum dihydrofolate-reductase (Pfdhfr) and Kelch 13 propeller domain on chromosome 13 (Kelch 13) genes. RESULTS: Of the 771 blood donors, 91 (11.8%) were positive by RDT. Analysis of sequence reads indicated successful genotyping of Pfcrt, Pfmdr1, Pfdhfr, Pfdhps and Kelch 13 genes in 84.6, 81.3, 86.8, 86.9 and 92.3% of the isolates respectively. Overall, 21 different mutant haplotypes were identified in 69 isolates (75.8%). In Pfcrt, CVIET haplotype was observed in 11.6% samples while in Pfmdr1, triple mutation (resulting in YFN haplotype) was detected in 8.1% of isolates. In Pfdhfr gene, triple mutation resulting in IRNI haplotype and in Pfdhps gene, quintuple mutation resulting in AGESS haplotype was identified in 17.7% parasite isolates. Finally, five non-synonymous Kelch 13 alleles were detected; C580Y (3.6%), P615L (4.8%), A578S (4.8%), I543V (2.4%) and A676S (1.2%) were detected. CONCLUSION: Results obtained in this study indicated various frequencies of mutant alleles in Pfcrt, Pfmdr1, Pfdhfr, Pfdhps and Kelch 13 genes from P. falciparum infected blood donors. These alleles could reduce the efficacy of standard malaria treatment in transfusion-transmitted malaria cases. Incorporating malaria screening into donor screening protocol to defer infected donors is therefore recommended.


Assuntos
Doadores de Sangue , Resistência Microbiana a Medicamentos/genética , Resistência a Múltiplos Medicamentos/genética , Malária Falciparum/tratamento farmacológico , Malária Falciparum/epidemiologia , Plasmodium falciparum/genética , Adolescente , Adulto , Alelos , Antimaláricos/uso terapêutico , Doenças Assintomáticas , Biomarcadores , Cloroquina/uso terapêutico , Estudos Transversais , Di-Hidropteroato Sintase/genética , Feminino , Frequência do Gene , Gana/epidemiologia , Haplótipos , Humanos , Repetição Kelch/genética , Malária Falciparum/diagnóstico , Malária Falciparum/parasitologia , Masculino , Proteínas de Membrana Transportadoras/genética , Pessoa de Meia-Idade , Proteínas Associadas à Resistência a Múltiplos Medicamentos/genética , Mutação , Plasmodium falciparum/isolamento & purificação , Prevalência , Proteínas de Protozoários/genética , Tetra-Hidrofolato Desidrogenase/genética , Adulto Jovem
15.
BMC Infect Dis ; 20(1): 513, 2020 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-32677899

RESUMO

BACKGROUND: Imported falciparum malaria from Africa has become a key public health challenge in Guizhou Province since 2012. Understanding the polymorphisms of molecular markers of drug resistance can guide selection of antimalarial drugs for the treatment of malaria. This study was aimed to analyze the polymorphisms of pfcrt, pfmdr1, and K13-propeller among imported falciparum malaria cases in Guizhou Province, China. METHOD: Fifty-five imported falciparum malaria cases in Guizhou Province during 2012-2016 were included in this study. Their demographic information and filter paper blood samples were collected. Genomic DNA of Plasmodium falciparum was extracted from the blood samples, and polymorphisms of pfcrt, pfmdr1, and K13-propeller were analyzed with nested PCR amplification followed by sequencing. Data were analyzed with the SPSS17.0 software. RESULTS: The prevalence of pfcrt K76T, pfmdr1 N86Y, and pfmdr1 Y184F mutation was 56.6, 22.2, and 72.2%, respectively, in imported falciparum malaria cases in Guizhou Province. We detected two mutant haplotypes of pfcrt, IET and MNT, with IET being more commonly found (54.7%), and five mutant haplotypes of pfmdr1, of which NFD was the most frequent (53.7%). There were totally 10 combined haplotypes of pfcrt and pfmdr1, of which the haplotype IETNFD possessed a predominance of 28.8%. In addition, three nonsynonymous mutations (S459T, C469F, and V692L) and two synonymous mutations (R471R and V589V) were detected in K13-propeller, all having prevalence less than 6.0%. In particular, a candidate K13 resistance mutation, C469F, was identified for the first time from Democratic Republic of the Congo with the prevalence of 2.0%. CONCLUSIONS: The high prevalence of IET haplotype of pfcrt and NFD haplotype of pfmdr1 suggests the presence of chloroquine, artemether/lumefantrine, and dihydroartemisinin/piperaquine resistance in these cases. Therefore cautions should be made to artemisinin therapy for P. falciparum in Africa. Continuous monitoring of anti-malarial drug efficacy in imported malaria cases is helpful for optimizing antimalarial drug therapy in Guizhou Province, China.


Assuntos
Doenças Transmissíveis Importadas/parasitologia , Resistência a Medicamentos/genética , Malária Falciparum/parasitologia , Plasmodium falciparum/genética , Polimorfismo Genético , Proteínas de Protozoários/genética , Adulto , África/epidemiologia , Substituição de Aminoácidos/genética , Antimaláricos/uso terapêutico , China/epidemiologia , Estudos de Coortes , Feminino , Humanos , Malária Falciparum/tratamento farmacológico , Malária Falciparum/epidemiologia , Masculino , Proteínas de Membrana Transportadoras/genética , Pessoa de Meia-Idade , Proteínas Associadas à Resistência a Múltiplos Medicamentos/genética , Mutação , Plasmodium falciparum/isolamento & purificação , Doença Relacionada a Viagens
16.
PLoS Negl Trop Dis ; 14(6): e0008255, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32530913

RESUMO

BACKGROUND: Vivax malaria is an important public health problem in the Greater Mekong Subregion (GMS), including the China-Myanmar border. Previous studies have found that Plasmodium vivax has decreased sensitivity to antimalarial drugs in some areas of the GMS, but the sensitivity of P. vivax to antimalarial drugs is unclear in the China-Myanmar border. Here, we investigate the drug sensitivity profile and genetic variations for two drug resistance related genes in P. vivax isolates to provide baseline information for future drug studies in the China-Myanmar border. METHODOLOGY/PRINCIPAL FINDINGS: A total of 64 P. vivax clinical isolates collected from the China-Myanmar border area were assessed for ex vivo susceptibility to eight antimalarial drugs by the schizont maturation assay. The medians of IC50 (half-maximum inhibitory concentrations) for chloroquine, mefloquine, pyronaridine, piperaquine, quinine, artesunate, artemether, dihydroartemisinin were 84.2 nM, 34.9 nM, 4.0 nM, 22.3 nM, 41.4 nM, 2.8 nM, 2.1 nM and 2.0 nM, respectively. Twelve P. vivax clinical isolates were found over the cut-off IC50 value (220 nM) for chloroquine resistance. In addition, sequence polymorphisms in pvmdr1 (P. vivax multidrug resistance-1), pvcrt-o (P. vivax chloroquine resistance transporter-o), and difference in pvmdr1 copy number were studied. Sequencing of the pvmdr1 gene in 52 samples identified 12 amino acid substitutions, among which two (G698S and T958M) were fixed, M908L were present in 98.1% of the isolates, while Y976F and F1076L were present in 3.8% and 78.8% of the isolates, respectively. Amplification of the pvmdr1 gene was only detected in 4.8% of the samples. Sequencing of the pvcrt-o in 59 parasite isolates identified a single lysine insertion at position 10 in 32.2% of the isolates. The pvmdr1 M908L substitutions in pvmdr1 in our samples was associated with reduced sensitivity to chloroquine, mefloquine, pyronaridine, piperaquine, quinine, artesunate and dihydroartemisinin. CONCLUSIONS: Our findings depict a drug sensitivity profile and genetic variations of the P. vivax isolates from the China-Myanmar border area, and suggest possible emergence of chloroquine resistant P. vivax isolates in the region, which demands further efforts for resistance monitoring and mechanism studies.


Assuntos
Antimaláricos/farmacologia , Resistência a Medicamentos , Malária Vivax/parasitologia , Proteínas de Membrana Transportadoras/genética , Proteínas Associadas à Resistência a Múltiplos Medicamentos/genética , Plasmodium vivax/efeitos dos fármacos , Polimorfismo Genético , Proteínas de Protozoários/genética , Adolescente , Adulto , Idoso , Criança , Pré-Escolar , China , Feminino , Genótipo , Humanos , Lactente , Concentração Inibidora 50 , Masculino , Pessoa de Meia-Idade , Mianmar , Testes de Sensibilidade Parasitária , Plasmodium vivax/isolamento & purificação , Análise de Sequência de DNA , Adulto Jovem
17.
Proc Natl Acad Sci U S A ; 117(21): 11207-11216, 2020 05 26.
Artigo em Inglês | MEDLINE | ID: mdl-32424102

RESUMO

Bacteria frequently encounter selection by both antibiotics and lytic bacteriophages. However, the evolutionary interactions between antibiotics and phages remain unclear, in particular, whether and when phages can drive evolutionary trade-offs with antibiotic resistance. Here, we describe Escherichia coli phage U136B, showing it relies on two host factors involved in different antibiotic resistance mechanisms: 1) the efflux pump protein TolC and 2) the structural barrier molecule lipopolysaccharide (LPS). Since TolC and LPS contribute to antibiotic resistance, phage U136B should select for their loss or modification, thereby driving a trade-off between phage resistance and either of the antibiotic resistance mechanisms. To test this hypothesis, we used fluctuation experiments and experimental evolution to obtain phage-resistant mutants. Using these mutants, we compared the accessibility of specific mutations (revealed in the fluctuation experiments) to their actual success during ecological competition and coevolution (revealed in the evolution experiments). Both tolC and LPS-related mutants arise readily during fluctuation assays, with tolC mutations becoming more common during the evolution experiments. In support of the trade-off hypothesis, phage resistance via tolC mutations occurs with a corresponding reduction in antibiotic resistance in many cases. However, contrary to the hypothesis, some phage resistance mutations pleiotropically confer increased antibiotic resistance. We discuss the molecular mechanisms underlying this surprising pleiotropic result, consideration for applied phage biology, and the importance of ecology in evolution of phage resistance. We envision that phages may be useful for the reversal of antibiotic resistance, but such applications will need to account for unexpected pleiotropy and evolutionary context.


Assuntos
Colífagos/fisiologia , Farmacorresistência Bacteriana/fisiologia , Escherichia coli/efeitos dos fármacos , Escherichia coli/fisiologia , Pleiotropia Genética , Antibacterianos/farmacologia , Proteínas da Membrana Bacteriana Externa/genética , Escherichia coli/virologia , Proteínas de Escherichia coli/genética , Biblioteca Gênica , Genes Bacterianos , Especificidade de Hospedeiro , Lipopolissacarídeos/genética , Lipopolissacarídeos/metabolismo , Proteínas de Membrana Transportadoras/genética , Mutação
18.
Nucleic Acids Res ; 48(10): 5426-5441, 2020 06 04.
Artigo em Inglês | MEDLINE | ID: mdl-32356892

RESUMO

Activator protein 1 (AP-1) is one of the largest families of basic leucine zipper (bZIP) transcription factors in eukaryotic cells. How AP-1 proteins achieve target DNA binding specificity remains elusive. In Saccharomyces cerevisiae, the AP-1-like protein (Yap) family comprises eight members (Yap1 to Yap8) that display distinct genomic target sites despite high sequence homology of their DNA binding bZIP domains. In contrast to the other members of the Yap family, which preferentially bind to short (7-8 bp) DNA motifs, Yap8 binds to an unusually long DNA motif (13 bp). It has been unclear what determines this unique specificity of Yap8. In this work, we use molecular and biochemical analyses combined with computer-based structural design and molecular dynamics simulations of Yap8-DNA interactions to better understand the structural basis of DNA binding specificity determinants. We identify specific residues in the N-terminal tail preceding the basic region, which define stable association of Yap8 with its target promoter. We propose that the N-terminal tail directly interacts with DNA and stabilizes Yap8 binding to the 13 bp motif. Thus, beside the core basic region, the adjacent N-terminal region contributes to alternative DNA binding selectivity within the AP-1 family.


Assuntos
Fatores de Transcrição de Zíper de Leucina Básica/química , Fatores de Transcrição de Zíper de Leucina Básica/metabolismo , DNA Fúngico/metabolismo , Proteínas de Saccharomyces cerevisiae/química , Proteínas de Saccharomyces cerevisiae/metabolismo , Fatores de Transcrição de Zíper de Leucina Básica/genética , DNA Fúngico/química , Proteínas de Membrana Transportadoras/genética , Simulação de Dinâmica Molecular , Mutação , Regiões Promotoras Genéticas , Ligação Proteica , Elementos de Resposta , Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/genética
19.
Plant Mol Biol ; 103(4-5): 561-580, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32405802

RESUMO

KEY MESSAGE: CmHKT1;1 selectively exports Na+ from plant cells. Upon NaCl stress, its expression increased in a salt-tolerant melon cultivar. Overexpression of CmHKT1;1 increased transgenic Arabidopsis salt tolerance through improved K+/Na+ balance. High-affinity K+ transporters (HKTs) are thought to be involved in reducing Na+ in plant shoots under salt stress and modulating salt tolerance, but their function in a moderately salt-tolerant species of melon (Cucumis melo L.) remains unclear. In this study, a Na+ transporter gene, CmHKT1;1 (GenBank accession number: MK986658), was isolated from melons based on genome data. The transcript of CmHKT1;1 was relatively more abundant in roots than in stems or leaves from melon seedlings. The tobacco transient expression system showed that CmHKT1;1 was plasma-membrane localized. Upon salt stress, CmHKT1;1 expression was more strongly upregulated in a salt-tolerant melon cultivar, 'Bingxuecui' (BXC) compared with a salt-sensitive cultivar, 'Yulu' (YL). Electrophysiological evidence demonstrated that CmHKT1;1 only transported Na+, rather than K+, when expressed in Xenopus laevis oocytes. Overexpression of CmHKT1;1 increased salt sensitivity in Saccharomyces cerevisiae and salt tolerance in Arabidopsis thaliana. Under NaCl treatments, transgenic Arabidopsis plants accumulated significantly lower concentrations of Na+ in shoots than wild type plants and showed a better K+/Na+ balance, leading to better Fv/Fm, root length, biomass, and enhanced plant growth. The CmHKT1;1 gene may serve as a useful candidate for improving crop salt tolerance.


Assuntos
Arabidopsis/metabolismo , Cucumis melo/metabolismo , Proteínas de Membrana Transportadoras/metabolismo , Plantas Geneticamente Modificadas/metabolismo , Potássio/metabolismo , Sódio/metabolismo , Arabidopsis/genética , Proteínas de Transporte de Cátions/genética , Proteínas de Transporte de Cátions/metabolismo , Clorofila/análise , Clonagem Molecular , Cucumis melo/genética , Regulação da Expressão Gênica de Plantas , Proteínas de Membrana Transportadoras/genética , Folhas de Planta/metabolismo , Proteínas de Plantas/genética , Raízes de Plantas/metabolismo , Brotos de Planta/genética , Saccharomyces cerevisiae/genética , Tolerância ao Sal , Plântula/genética , Plântula/metabolismo , Alinhamento de Sequência , Análise de Sequência de Proteína , Cloreto de Sódio/metabolismo , Estresse Fisiológico/genética , Estresse Fisiológico/fisiologia , Simportadores/genética , Simportadores/metabolismo , Tabaco/genética , Tabaco/metabolismo
20.
PLoS One ; 15(5): e0226453, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32379825

RESUMO

Membrane transporters carry key metabolites across the cell membrane and, from a resource standpoint, are hypothesized to be produced when necessary. The expression of membrane transporters in metabolic pathways is often upregulated by the transporter substrate. In E. coli, such systems include for example the lacY, araFGH, and xylFGH genes, which encode for lactose, arabinose, and xylose transporters, respectively. As a case study of a minimal system, we build a generalizable physical model of the xapABR genetic circuit, which features a regulatory feedback loop via membrane transport (positive feedback) and enzymatic degradation (negative feedback) of an inducer. Dynamical systems analysis and stochastic simulations show that the membrane transport makes the model system bistable in certain parameter regimes. Thus, it serves as a genetic "on-off" switch, enabling the cell to only produce a set of metabolic enzymes when the corresponding metabolite is present in large amounts. We find that the negative feedback from the degradation enzyme does not significantly disturb the positive feedback from the membrane transporter. We investigate hysteresis in the switching and discuss the role of cooperativity and multiple binding sites in the model circuit. Fundamentally, this work explores how a stable genetic switch for a set of enzymes is obtained from transcriptional auto-activation of a membrane transporter through its substrate.


Assuntos
Adaptação Fisiológica/genética , Escherichia coli/genética , Escherichia coli/metabolismo , Redes Reguladoras de Genes , Genes de Troca , Modelos Biológicos , Sítios de Ligação , Transporte Biológico/genética , Proteínas de Escherichia coli/genética , Proteínas de Escherichia coli/metabolismo , Retroalimentação Fisiológica , Regulação Bacteriana da Expressão Gênica , Proteínas de Membrana Transportadoras/genética , Proteínas de Membrana Transportadoras/metabolismo , Pentosiltransferases/genética , Pentosiltransferases/metabolismo , Regiões Promotoras Genéticas , RNA Mensageiro/metabolismo , Ribonucleosídeos/metabolismo , Processos Estocásticos , Transativadores/genética , Transativadores/metabolismo , Transcrição Genética
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