Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 9.689
Filtrar
1.
Arch Microbiol ; 206(4): 155, 2024 Mar 13.
Artigo em Inglês | MEDLINE | ID: mdl-38480568

RESUMO

Glucose, which plays an essential role in carbon and energy metabolism in eukaryotes, is vital in directing various energy-consuming cellular processes. In S. cerevisiae, transcription factors involved in regulating hexose transporters and their mechanisms of action under different carbon sources were revealed in detail. However, there is limited information on these processes in S. pombe. In this study, the effect of SPCC320.03 (named SpRgt1), the ortholog of ScRgt1 whose molecular mechanism is known in detail in S. cerevisiae, on the transcriptional regulation of hexose transporters (ght1-8) dependent on different carbon sources was investigated. We measured the transcript levels of ght1-8 using the qPCR technique and performed relative evaluation in S. pombe strains (parental, rgt1 deleted mutant, rgt1 overexpressed, and vectoral rgt1 carrying mutant). We aimed to investigate the transcriptional changes caused by the protein product of the rgt1 (SPCC320.03) gene in terms of ght1-8 genes in strains that are grown in different carbon sources (2% glucose, 2% glycerol + 0.1% glucose, and 2% gluconate). Here, we show that SpRgt1 is involved in the regulation of the ght3, ght4, ght6, and ght7 genes but that the ght1, ght2, ght5, and ght8 gene expression vary depending on carbon sources, independently of SpRgt1.


Assuntos
Schizosaccharomyces , Carbono/metabolismo , DNA , Expressão Gênica , Regulação Fúngica da Expressão Gênica , Glucose/metabolismo , Proteínas de Transporte de Monossacarídeos/genética , Proteínas de Transporte de Monossacarídeos/metabolismo , Saccharomyces cerevisiae/genética , Schizosaccharomyces/genética , Schizosaccharomyces/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo
2.
Sci Rep ; 14(1): 4055, 2024 02 19.
Artigo em Inglês | MEDLINE | ID: mdl-38374219

RESUMO

The plasma membrane proteins Rgt2 and Snf3 are glucose sensing receptors (GSRs) that generate an intracellular signal for the induction of gene expression in response to high and low extracellular glucose concentrations, respectively. The GSRs consist of a 12-transmembrane glucose recognition domain and a cytoplasmic C-terminal signaling tail. The GSR tails are dissimilar in length and sequence, but their distinct roles in glucose signal transduction are poorly understood. Here, we show that swapping the tails between Rgt2 and Snf3 does not alter the signaling activity of the GSRs, so long as their tails are phosphorylated in a Yck-dependent manner. Attachment of the GSR tails to Hxt1 converts the transporter into a glucose receptor; however, the tails attached to Hxt1 are not phosphorylated by the Ycks, resulting in only partial signaling. Moreover, in response to non-fermentable carbon substrates, Rgt2 and Hxt1-RT (RT, Rgt2-tail) are efficiently endocytosed, whereas Snf3 and Hxt1-ST (ST, Snf3-tail) are endocytosis-impaired. Thus, the tails are important regulatory domains required for the endocytosis of the Rgt2 and Snf3 glucose sensing receptors triggered by different cellular stimuli. Taken together, these results suggest multiple roles for the tail domains in GSR-mediated glucose sensing and signaling.


Assuntos
Proteínas de Transporte de Monossacarídeos , Proteínas de Saccharomyces cerevisiae , Saccharomyces cerevisiae , Regulação Fúngica da Expressão Gênica , Glucose/metabolismo , Proteínas de Transporte de Monossacarídeos/genética , Receptores de Superfície Celular/metabolismo , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismo , Transdução de Sinais
3.
Rinsho Ketsueki ; 65(1): 35-40, 2024.
Artigo em Japonês | MEDLINE | ID: mdl-38311387

RESUMO

A 64-year-old woman presented with fine motor impairment in both hands. MRI revealed a contrast-enhanced lesion in the medulla oblongata. Lymphoid cells with abnormal blebs were observed and a CD4+/CD8+ double positive (DP) T cell population was detected by flow cytometry (FCM) in the bone marrow (BM) and the peripheral blood (PB). CLEC16A::IL2 fusion gene was identified by whole exome sequencing with DNA prepared from DP T cells. Clonal rearrangement of the T-cell receptor gene and expression of TCL1A protein were detected. This led to a diagnosis of T-cell prolymphocytic leukemia (T-PLL) with central nervous system (CNS) infiltration. Abnormal cells in BM and PB became undetectable on microscopy and FCM, and the CNS lesion disappeared on MRI after second-line therapy with alemtuzumab. Meanwhile, the CLEC16A::IL2 fusion mRNA remained detectable in PB. Allogeneic hematopoietic stem-cell transplantation was performed, and the fusion mRNA has now been undetectable for more than 5 years since transplantation. This is the first report of a T-PLL case with a CLEC16A::IL2 fusion gene.


Assuntos
Transplante de Células-Tronco Hematopoéticas , Leucemia Prolinfocítica de Células T , Feminino , Humanos , Pessoa de Meia-Idade , Leucemia Prolinfocítica de Células T/genética , Leucemia Prolinfocítica de Células T/metabolismo , Leucemia Prolinfocítica de Células T/terapia , Interleucina-2/metabolismo , Alemtuzumab , RNA Mensageiro , Proteínas de Transporte de Monossacarídeos , Lectinas Tipo C/genética
4.
Biochem Biophys Res Commun ; 696: 149494, 2024 Feb 12.
Artigo em Inglês | MEDLINE | ID: mdl-38219491

RESUMO

Skeletal muscle is the largest metabolic tissue responsible for systemic glucose handling. Glucose uptake into skeletal tissue is highly dynamic and delicately regulated, in part through the controlled expression and subcellular trafficking of multiple types of glucose transporters. Although the roles of GLUT4 in skeletal muscle metabolism are well established, the physiological significance of other, seemingly redundant, glucose transporters remain incompletely understood. Nonetheless, recent studies have shed light on the roles of several glucose transporters, such as GLUT1 and GLUT10, in skeletal muscle. Mice experiments suggest that GLUT10 could be a novel player in skeletal muscle metabolism in the context of mechanical overload, which is in line with the meta-analytical results of gene expression changes after resistance exercise in humans. Herein we discuss the knowns, unknowns, and implications of these recent findings.


Assuntos
Proteínas Facilitadoras de Transporte de Glucose , Proteínas de Transporte de Monossacarídeos , Humanos , Camundongos , Animais , Proteínas Facilitadoras de Transporte de Glucose/genética , Proteínas Facilitadoras de Transporte de Glucose/metabolismo , Proteínas de Transporte de Monossacarídeos/genética , Músculo Esquelético/metabolismo , Glucose/metabolismo , Transporte Biológico , Transportador de Glucose Tipo 4/genética , Transportador de Glucose Tipo 4/metabolismo , Insulina/metabolismo , Transportador de Glucose Tipo 1/genética , Transportador de Glucose Tipo 1/metabolismo
5.
Mol Genet Metab ; 141(3): 108144, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38277989

RESUMO

Glycogen storage disease type Ib (GSD Ib, biallelic variants in SLC37A4) is a rare disorder of glycogen metabolism complicated by neutropenia/neutrophil dysfunction. Since 2019, the SGLT2-inhibitor empagliflozin has provided a mechanism-based treatment option for the symptoms caused by neutropenia/neutrophil dysfunction (e.g. mucosal lesions, inflammatory bowel disease). Because of the rarity of GSD Ib, the published evidence on safety and efficacy of empagliflozin is still limited and does not allow to develop evidence-based guidelines. Here, an international group of experts provides 14 best practice consensus treatment recommendations based on expert practice and review of the published evidence. We recommend to start empagliflozin in all GSD Ib individuals with clinical or laboratory signs related to neutropenia/neutrophil dysfunction with a dose of 0.3-0.4 mg/kg/d given as a single dose in the morning. Treatment can be started in an outpatient setting. The dose should be adapted to the weight and in case of inadequate clinical treatment response or side effects. We strongly recommend to pause empagliflozin immediately in case of threatening dehydration and before planned longer surgeries. Discontinuation of G-CSF therapy should be attempted in all individuals. If available, 1,5-AG should be monitored. Individuals who have previously not tolerated starches should be encouraged to make a new attempt to introduce starch in their diet after initiation of empagliflozin treatment. We advise to monitor certain safety and efficacy parameters and recommend continuous, alternatively frequent glucose measurements during the introduction of empagliflozin. We provide specific recommendations for special circumstances like pregnancy and liver transplantation.


Assuntos
Compostos Benzidrílicos , Glucosídeos , Doença de Depósito de Glicogênio Tipo I , Neutropenia , Humanos , Neutrófilos/metabolismo , Consenso , Doença de Depósito de Glicogênio Tipo I/complicações , Doença de Depósito de Glicogênio Tipo I/tratamento farmacológico , Doença de Depósito de Glicogênio Tipo I/genética , Neutropenia/tratamento farmacológico , Neutropenia/etiologia , Proteínas de Transporte de Monossacarídeos , Antiporters/metabolismo
6.
Plant Cell Rep ; 43(1): 29, 2024 Jan 06.
Artigo em Inglês | MEDLINE | ID: mdl-38183427

RESUMO

KEY MESSAGE: OsSWEET1b is a hexose transporter protein, which localized in cell membranes and interacting with itself to form homodimer and knockout of OsSWEET1b resulted in reduced leaves sugar content and accelerating leaf senescence. In the rice genome, the SWEET gene family contains 21 homologous members, but the role of some of them in rice growth and development is still unknown. The function of the sugar transporter OsSWEET1b protein in rice was identified in this research. Expression analysis showed that the expression levels of OsSWEET1b in leaves were higher than that in other tissues. The hexose transport experiment confirmed that OsSWEET1b has glucose and galactose transporter activity in yeast. Subcellular localization indicates that OsSWEET1b protein was targeted to the plasma membrane and BiFC analysis showed that OsSWEET1b interacts with itself to form homodimers. Functional analysis demonstrated that the ossweet1b mutant plants were have reduced the sucrose, glucose, fructose, starch and galactose contents, and induced carbon starvation-related gene expression, which might lead to carbon starvation in leaves at filling stage. The ossweet1b knockout plants showed decreased chlorophyll content and antioxidant enzyme activity, and increased ROS accumulation in leaves, leading to leaf cell death and premature senescence phenotype at filling stage. In ossweet1b mutants, the leaf senescence-related gene expression levels were increased and the abundance of photosynthesis-related proteins was decreased. Loss of OsSWEET1b were affected the starch, sucrose metabolism and carbon fixation in photosynthetic organelles pathway by RNA-seq analysis. The destruction of OsSWEET1b function will cause sugar starvation, decreased photosynthesis and leaf senescence, which leading to reduced rice yield. Collectively, our results suggest that the OsSWEET1b plays a key role in rice leaves carbohydrate metabolism and leaf senescence.


Assuntos
Galactose , Proteínas de Transporte de Monossacarídeos , Proteínas de Transporte de Monossacarídeos/genética , Senescência Vegetal , Metabolismo dos Carboidratos , Glucose , Antioxidantes , Carbono , Membrana Celular , Amido , Sacarose
7.
Int J Mol Sci ; 25(2)2024 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-38279332

RESUMO

Pollen cells require large amounts of sugars from the anther to support their development, which is critical for plant sexual reproduction and crop yield. Sugars Will Eventually be Exported Transporters (SWEETs) have been shown to play an important role in the apoplasmic unloading of sugars from anther tissues into symplasmically isolated developing pollen cells and thereby affect the sugar supply for pollen development. However, among the 17 CsSWEET genes identified in the cucumber (Cucumis sativus L.) genome, the CsSWEET gene involved in this process has not been identified. Here, a member of the SWEET gene family, CsSWEET5a, was identified and characterized. The quantitative real-time PCR and ß-glucuronidase expression analysis revealed that CsSWEET5a is highly expressed in the anthers and pollen cells of male cucumber flowers from the microsporocyte stage (stage 9) to the mature pollen stage (stage 12). Its subcellular localization indicated that the CsSWEET5a protein is localized to the plasma membrane. The heterologous expression assays in yeast demonstrated that CsSWEET5a encodes a hexose transporter that can complement both glucose and fructose transport deficiencies. CsSWEET5a can significantly rescue the pollen viability and fertility of atsweet8 mutant Arabidopsis plants. The possible role of CsSWEET5a in supplying hexose to developing pollen cells via the apoplast is also discussed.


Assuntos
Arabidopsis , Cucumis sativus , Arabidopsis/genética , Arabidopsis/metabolismo , Cucumis sativus/metabolismo , Proteínas de Transporte de Monossacarídeos/genética , Proteínas de Transporte de Monossacarídeos/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Hexoses/metabolismo , Pólen/genética , Pólen/metabolismo , Saccharomyces cerevisiae/metabolismo , Fertilidade/genética , Regulação da Expressão Gênica de Plantas
8.
J Adv Res ; 57: 93-105, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-37100345

RESUMO

INTRODUCTION: Growing evidence has shown the correlation between periodontitis and atherosclerosis, while our knowledge on the pathogenesis of periodontitis-promoting atherosclerosis is far from sufficient. OBJECTIVES: Illuminate the pathogenic effects of Fusobacterium nucleatum (F. nucleatum) on intracellular lipid deposition in THP-1-derived macrophages and elucidate the underlying pathogenic mechanism of how F. nucleatum promoting atherosclerosis. METHODS AND RESULTS: F. nucleatum was frequently detected in different kinds of atherosclerotic plaques and its abundance was positively correlated with the proportion of macrophages. In vitro assays showed F. nucleatum could adhere to and invade THP-1 cells, and survive continuously in macrophages for 24 h. F. nucleatum stimulation alone could significantly promote cellular inflammation, lipid uptake and inhibit lipid outflow. The dynamic gene expression of THP-1 cells demonstrated that F. nucleatum could time-serially induce the over-expression of multiple inflammatory related genes and activate NF-κB, MAPK and PI3K-AKT signaling pathways. The exoprotein of F. nucleatum, D-galactose-binding protein (Gbp), acted as one of the main pathogenic proteins to interact with the Cyclophilin A (CypA) of THP-1 cells and induced the activation of the NF- κB, MAPK and PI3K-AKT signaling pathways. Furthermore, use of six candidate drugs targeting to the key proteins in NF- κB, MAPK and PI3K-AKT pathways could dramatically decrease F. nucleatum induced inflammation and lipid deposition in THP-1 cells. CONCLUSIONS: This study suggests that the periodontal pathogen F. nucleatum can activate macrophage PI3K-AKT/MAPK/NF-κB signal pathways, promotes inflammation, enhances cholesterol uptake, reduces lipid excretion, and promotes lipid deposition, which may be one of its main strategies promoting the development of atherosclerosis.


Assuntos
Aterosclerose , Proteínas de Ligação ao Cálcio , Proteínas de Transporte de Monossacarídeos , Periodontite , Proteínas Periplásmicas de Ligação , Humanos , NF-kappa B , Ciclofilina A , Fusobacterium nucleatum , Fosfatidilinositol 3-Quinases , Proteínas Proto-Oncogênicas c-akt , Células THP-1 , Inflamação , Lipídeos
9.
Br J Haematol ; 204(1): 45-55, 2024 01.
Artigo em Inglês | MEDLINE | ID: mdl-38049194

RESUMO

Neutrophils are the shortest-lived blood cells, which requires a prodigious degree of proliferation and differentiation to sustain physiologically sufficient numbers and be poised to respond quickly to infectious emergencies. More than 107 neutrophils are produced every minute in an adult bone marrow-a process that is tightly regulated by a small group of cytokines and chemical mediators and dependent on nutrients and energy. Like granulocyte colony-stimulating factor, the primary growth factor for granulopoiesis, they stimulate signalling pathways, some affecting metabolism. Nutrient or energy deficiency stresses the survival, proliferation, and differentiation of neutrophils and their precursors. Thus, it is not surprising that monogenic disorders related to metabolism exist that result in neutropenia. Among these are pathogenic mutations in HAX1, G6PC3, SLC37A4, TAFAZZIN, SBDS, EFL1 and the mitochondrial disorders. These mutations perturb carbohydrate, lipid and/or protein metabolism. We hypothesize that metabolic disturbances may drive the pathogenesis of a subset of inherited neutropenias just as defects in DNA damage response do in Fanconi anaemia, telomere maintenance in dyskeratosis congenita and ribosome formation in Diamond-Blackfan anaemia. Greater understanding of metabolic pathways in granulopoiesis will identify points of vulnerability in production and may point to new strategies for the treatment of neutropenias.


Assuntos
Doenças da Medula Óssea , Anemia de Fanconi , Neutropenia , Adulto , Humanos , Doenças da Medula Óssea/genética , Anemia de Fanconi/genética , Medula Óssea/patologia , Transtornos da Insuficiência da Medula Óssea , Neutropenia/patologia , Proteínas Adaptadoras de Transdução de Sinal , Proteínas de Transporte de Monossacarídeos , Antiporters
10.
J Int Med Res ; 51(12): 3000605231216633, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-38087503

RESUMO

Glycogen storage disease type 1b (GSD1b) is a rare genetic disorder, resulting from mutations in the SLC37A4 gene located on chromosome 11q23.3. Although the SLC37A4 gene has been identified as the pathogenic gene for GSD1b, the complete variant spectrum of this gene remains to be fully elucidated. In this study, we present three patients diagnosed with GSD1b through genetic testing. We detected five variants of the SLC37A4 gene in these three patients, with three of these mutations (p. L382Pfs*15, p. G117fs*28, and p. T312Sfs*13) being novel variants not previously reported in the literature. We also present a literature review and general overview of the currently reported SLC37A4 gene variants. Our study expands the mutation spectrum of SLC37A4, which may help enable genetic testing to facilitate prompt diagnosis, appropriate intervention, and genetic counseling for affected families.


Assuntos
Doença de Depósito de Glicogênio Tipo I , Doença de Depósito de Glicogênio , Humanos , Antiporters/genética , Testes Genéticos , Doença de Depósito de Glicogênio/genética , Doença de Depósito de Glicogênio Tipo I/diagnóstico , Doença de Depósito de Glicogênio Tipo I/genética , Proteínas de Transporte de Monossacarídeos/genética , Mutação/genética
11.
ACS Infect Dis ; 9(12): 2560-2571, 2023 Dec 08.
Artigo em Inglês | MEDLINE | ID: mdl-37936289

RESUMO

We report a maltose-derivatized fluorescence turn-on imaging probe, Mal-Cz, to detect E. coli and Staphylococci. The fluorescence turn-on is achieved through an intramolecular C-H insertion reaction of the perfluoroaryl azide-functionalized carbazole to give a fluorescent product. Confocal fluorescence microscopy confirmed the successful uptake of Mal-Cz by E. coli and Staphylococci upon photoactivation. The Mal-Cz probe could selectively detect E. coli and S. epidermidis in the presence of P. aeruginosa and M. smegmatis without interference from these bacteria. Both the photoactivation and bacteria detection can be accomplished using a hand-held UV lamp at 365 nm, with the limit of detection of 103 CFU/mL by the naked eye. Mal-Cz could also be used to detect E. coli and S. epidermidis spiked in milk by the naked eye under a hand-held UV lamp. The uptake of Mal-Cz requires metabolically active bacteria: the uptake was reduced in stationary phase bacteria and was diminished in bacteria that were killed by heating or treating with antibiotics or sodium azide. The uptake decreased with increasing concentration of added free maltose, indicating that Mal-Cz hijacked the maltose uptake pathways. In E. coli, the maltose transport systems, including maltoporin LamB, maltose binding protein MBP, and the maltose ATP binding cassette (ABC) transporter MalFGK2, are all critical for the transport of Mal-Cz. The uptake was diminished in the deletion mutants ΔLamB, ΔMalE, ΔMalF, and ΔMalK.


Assuntos
Proteínas de Escherichia coli , Maltose , Maltose/metabolismo , Escherichia coli/genética , Escherichia coli/metabolismo , Proteínas de Transporte de Monossacarídeos/metabolismo , Proteínas de Escherichia coli/metabolismo , Fluorescência , Transportadores de Cassetes de Ligação de ATP/metabolismo
12.
Front Endocrinol (Lausanne) ; 14: 1265698, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-38034009

RESUMO

Background: Glycogen plays an important role in glucose homeostasis and contributes to key functions related to brain cancer cell survival in glioblastoma multiforme (GBM) disease progression. Such adaptive molecular mechanism is dependent on the glycogenolytic pathway and intracellular glucose-6-phosphate (G6P) sensing by brain cancer cells residing within those highly hypoxic tumors. The involvement of components of the glucose-6-phosphatase (G6Pase) system remains however elusive. Objective: We questioned the gene expression levels of components of the G6Pase system in GBM tissues and their functional impact in the control of the invasive and brain cancer stem cells (CSC) phenotypes. Methods: In silico analysis of transcript levels in GBM tumor tissues was done by GEPIA. Total RNA was extracted and gene expression of G6PC1-3 as well as of SLC37A1-4 members analyzed by qPCR in four human brain cancer cell lines and from clinically annotated brain tumor cDNA arrays. Transient siRNA-mediated gene silencing was used to assess the impact of TGF-ß-induced epithelial-to-mesenchymal transition (EMT) and cell chemotaxis. Three-dimensional (3D) neurosphere cultures were generated to recapitulate the brain CSC phenotype. Results: Higher expression in G6PC3, SLC37A2, and SLC37A4 was found in GBM tumor tissues in comparison to low-grade glioma and healthy tissue. The expression of these genes was also found elevated in established human U87, U251, U118, and U138 GBM cell models compared to human HepG2 hepatoma cells. SLC37A4/G6PC3, but not SLC37A2, levels were induced in 3D CD133/SOX2-positive U87 neurospheres when compared to 2D monolayers. Silencing of SLC37A4/G6PC3 altered TGF-ß-induced EMT biomarker SNAIL and cell chemotaxis. Conclusion: Two members of the G6Pase system, G6PC3 and SLC37A4, associate with GBM disease progression and regulate the metabolic reprogramming of an invasive and CSC phenotype. Such molecular signature may support their role in cancer cell survival and chemoresistance and become future therapeutic targets.


Assuntos
Neoplasias Encefálicas , Glioblastoma , Humanos , Antiporters/genética , Antiporters/metabolismo , Encéfalo/metabolismo , Neoplasias Encefálicas/metabolismo , Glioblastoma/metabolismo , Glucose-6-Fosfatase/genética , Glucose-6-Fosfatase/metabolismo , Proteínas de Transporte de Monossacarídeos/genética , Proteínas de Transporte de Monossacarídeos/metabolismo , Células-Tronco Neoplásicas/metabolismo , Fenótipo , Fator de Crescimento Transformador beta/metabolismo
13.
J Biol Chem ; 299(12): 105389, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37890779

RESUMO

Sugars Will Eventually be Exported Transporters (SWEETs) are central for sugar allocation in plants. The SWEET family has approximately 20 homologs in most plant genomes, and despite extensive research on their structures and molecular functions, it is still unclear how diverse SWEETs recognize different substrates. Previous work using SweetTrac1, a biosensor constructed by the intramolecular fusion of a conformation-sensitive fluorescent protein in the plasma membrane transporter SWEET1 from Arabidopsis thaliana, identified common features in the transporter's substrates. Here, we report SweetTrac2, a new biosensor based on the Arabidopsis vacuole membrane transporter SWEET2, and use it to explore the substrate specificity of this second protein. Our results show that SWEET1 and SWEET2 recognize similar substrates but some with different affinities. Sequence comparison and mutagenesis analysis support the conclusion that the differences in affinity depend on nonspecific interactions involving previously uncharacterized residues in the substrate-binding pocket. Furthermore, SweetTrac2 can be an effective tool for monitoring sugar transport at vacuolar membranes that would be otherwise challenging to study.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Proteínas de Transporte de Monossacarídeos , Arabidopsis/metabolismo , Proteínas de Arabidopsis/metabolismo , Transporte Biológico , Regulação da Expressão Gênica de Plantas , Proteínas de Membrana Transportadoras/metabolismo , Proteínas de Transporte de Monossacarídeos/metabolismo , Proteínas de Plantas/metabolismo , Açúcares/metabolismo
14.
Biochim Biophys Acta Gen Subj ; 1867(12): 130490, 2023 12.
Artigo em Inglês | MEDLINE | ID: mdl-37844739

RESUMO

BACKGROUND: The yeast S. cerevisiae preferably metabolizes glucose through aerobic glycolysis. Glucose transport is facilitated by multiple hexose transporters (Hxts), and their expression and activity are tightly regulated by multiple mechanisms. However, detailed structural and functional analyses of Hxts remain limited, largely due to the lack of crystal structure. METHODS: Homology modeling was used to build a 3D structural model for the yeast glucose transporter Hxt1 and investigate the effects of site directed mutations on Hxt1 stability and glucose transport activity. RESULTS: The conserved salt bridge-forming residues observed in the human Glut4 and the yeast glucose receptor Rgt2 were identified within and between the two 6-transmembrane spanning segments of Hxt1. Most of the RGT2 mutations that disrupt the salt bridge networks were known to cause constitutive signal generation, whereas the corresponding substitutions in HXT1 were shown to decrease Hxt1 stability. While substitutions of the two residues in the salt bridge 2 in Glut4-E329Q and E393D-were reported to abolish glucose transport, the equivalent substitutions in Hxt1 (D382Q and E454D) did not affect Hxt1 glucose transport activity. CONCLUSIONS: Substitutions of equivalent salt bridge-forming residues in Hxt1, Rgt2, and Glut4 are predicted to lock them in an inward-facing conformation but lead to different functional consequences. GENERAL SIGNIFICANCE: The salt bridge networks in yeast and human glucose transporters and yeast glucose receptors may play different roles in maintaining their structural and functional integrity.


Assuntos
Proteínas de Saccharomyces cerevisiae , Saccharomyces cerevisiae , Humanos , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Proteínas de Transporte de Monossacarídeos/genética , Proteínas de Transporte de Monossacarídeos/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Proteínas Facilitadoras de Transporte de Glucose/genética , Proteínas Facilitadoras de Transporte de Glucose/metabolismo , Glucose/metabolismo
15.
FEBS Lett ; 597(18): 2345-2357, 2023 09.
Artigo em Inglês | MEDLINE | ID: mdl-37552213

RESUMO

SLC35A2 and SLC35A3 are homologous proteins with postulated nucleotide sugar transporting activities. Unlike SLC35A2, whose specificity for UDP-Gal is well-established, the UDP-GlcNAc transporting activity initially attributed to SLC35A3 has recently been put into question. In this study, we constructed two hybrid proteins (SLC35A2-SLC35A3 and SLC35A3-SLC35A2) and expressed them in a previously generated SLC35A2/SLC35A3 double knockout HEK293T cell line. Our idea was to force equivalent stoichiometry of the two proteins in the cells in order to reproduce the behavior of the SLC35A2/SLC35A3 complexes in the Golgi membrane. The hybrid proteins were able to fully restore glycosylation in the double knockout. In contrast, the expression of SLC35A3 alone in these cells improved galactosylation only to a limited extent. Our study shows that the proper glycosylation requires a balanced cooperation between SLC35A2 and SLC35A3.


Assuntos
Proteínas de Transporte de Monossacarídeos , Difosfato de Uridina , Humanos , Glicosilação , Proteínas de Transporte de Monossacarídeos/genética , Proteínas de Transporte de Monossacarídeos/metabolismo , Células HEK293 , Transporte Biológico , Difosfato de Uridina/metabolismo
16.
Cell Mol Life Sci ; 80(9): 259, 2023 Aug 18.
Artigo em Inglês | MEDLINE | ID: mdl-37594549

RESUMO

Neutropenia and neutrophil dysfunction in glycogen storage disease type 1b (GSD1b) and severe congenital neutropenia type 4 (SCN4), associated with deficiencies of the glucose-6-phosphate transporter (G6PT/SLC37A4) and the phosphatase G6PC3, respectively, are the result of the accumulation of 1,5-anhydroglucitol-6-phosphate in neutrophils. This is an inhibitor of hexokinase made from 1,5-anhydroglucitol (1,5-AG), an abundant polyol in blood. 1,5-AG is presumed to be reabsorbed in the kidney by a sodium-dependent-transporter of uncertain identity, possibly SGLT4/SLC5A9 or SGLT5/SLC5A10. Lowering blood 1,5-AG with an SGLT2-inhibitor greatly improved neutrophil counts and function in G6PC3-deficient and GSD1b patients. Yet, this effect is most likely mediated indirectly, through the inhibition of the renal 1,5-AG transporter by glucose, when its concentration rises in the renal tubule following inhibition of SGLT2. To identify the 1,5-AG transporter, both human and mouse SGLT4 and SGLT5 were expressed in HEK293T cells and transport measurements were performed with radiolabelled compounds. We found that SGLT5 is a better carrier for 1,5-AG than for mannose, while the opposite is true for human SGLT4. Heterozygous variants in SGLT5, associated with a low level of blood 1,5-AG in humans cause a 50-100% reduction in 1,5-AG transport activity tested in model cell lines, indicating that SGLT5 is the predominant kidney 1,5-AG transporter. These and other findings led to the conclusion that (1) SGLT5 is the main renal transporter of 1,5-AG; (2) frequent heterozygous mutations (allelic frequency > 1%) in SGLT5 lower blood 1,5-AG, favourably influencing neutropenia in G6PC3 or G6PT deficiency; (3) the effect of SGLT2-inhibitors on blood 1,5-AG level is largely indirect; (4) specific SGLT5-inhibitors would be more efficient to treat these neutropenias than SGLT2-inhibitors.


Assuntos
Neutropenia , Animais , Humanos , Camundongos , Antiporters , Células HEK293 , Rim , Proteínas de Membrana Transportadoras , Proteínas de Transporte de Monossacarídeos/genética , Neutropenia/genética , Transportador 2 de Glucose-Sódio/genética
17.
Plant Physiol ; 193(3): 2141-2163, 2023 Oct 26.
Artigo em Inglês | MEDLINE | ID: mdl-37427783

RESUMO

Regulation of intracellular sugar homeostasis is maintained by regulation of activities of sugar import and export proteins residing at the tonoplast. We show here that the EARLY RESPONSE TO DEHYDRATION6-LIKE4 (ERDL4) protein, a member of the monosaccharide transporter family, resides in the vacuolar membrane in Arabidopsis (Arabidopsis thaliana). Gene expression and subcellular fractionation studies indicated that ERDL4 participates in fructose allocation across the tonoplast. Overexpression of ERDL4 increased total sugar levels in leaves due to a concomitantly induced stimulation of TONOPLAST SUGAR TRANSPORTER 2 (TST2) expression, coding for the major vacuolar sugar loader. This conclusion is supported by the finding that tst1-2 knockout lines overexpressing ERDL4 lack increased cellular sugar levels. ERDL4 activity contributing to the coordination of cellular sugar homeostasis is also indicated by 2 further observations. First, ERDL4 and TST genes exhibit an opposite regulation during a diurnal rhythm, and second, the ERDL4 gene is markedly expressed during cold acclimation, representing a situation in which TST activity needs to be upregulated. Moreover, ERDL4-overexpressing plants show larger rosettes and roots, a delayed flowering time, and increased total seed yield. Consistently, erdl4 knockout plants show impaired cold acclimation and freezing tolerance along with reduced plant biomass. In summary, we show that modification of cytosolic fructose levels influences plant organ development and stress tolerance.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Frutose , Proteínas de Transporte de Monossacarídeos/genética , Proteínas de Transporte de Monossacarídeos/metabolismo , Transporte Biológico/genética , Arabidopsis/metabolismo , Carboidratos , Regulação da Expressão Gênica de Plantas , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas/metabolismo
18.
Front Immunol ; 14: 1155182, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37275857

RESUMO

Background: Solute carrier family 35 member A2 (SLC35A2), which belongs to the SLC35 solute carrier family of human nucleoside sugar transporters, has shown regulatory roles in various tumors and neoplasms. However, the function of SLC35A2 across human cancers remains to be systematically assessed. Insights into the prediction ability of SLC35A2 in clinical practice and immunotherapy response remains limited. Materials and methods: We obtained the gene expression and protein levels of SLC35A2 in a variety of tumors from Molecular Taxonomy of Breast Cancer International Consortium, The Cancer Genome Atlas, Gene Expression Omnibus, Chinese Glioma Genome Atlas, and Human Protein Atlas databases. The SLC35A2 level was validated by immunohistochemistry. The predictive value for prognosis was evaluated by Kaplan-Meier survival and Cox regression analyses. Correlations between SLC35A2 expression and DNA methylation, genetic alterations, tumor mutation burden (TMB), microsatellite instability (MSI), and tumor microenvironment were performed using Spearman's correlation analysis. The possible downstream pathways of SLC35A2 in different human cancers were explored using gene set variation analysis. The potential role of SLC35A2 in the tumor immune microenvironment was evaluated via EPIC, CIBERSORT, MCP-counter, CIBERSORT-ABS, quanTIseq, TIMER, and xCell algorithms. The difference in the immunotherapeutic response of SLC35A2 under different expression conditions was evaluated by the tumor immune dysfunction and exclusion (TIDE) score as well as four independent immunotherapy cohorts, which includes patients with bladder urothelial carcinoma (BLCA, N = 299), non-small cell lung cancer (NSCLC, N = 72 and N = 36) and skin cutaneous melanoma (SKCM, N = 25). Potential drugs were identified using the CellMiner database and molecular docking. Results: SLC35A2 exhibited abnormally high or low expression in 23 cancers and was significantly associated with the prognosis. In various cancers, SLC35A2 expression and mammalian target of rapamycin complex 1 signaling were positively correlated. Multiple algorithmic immune infiltration analyses suggested an inverse relation between SLC35A2 expression and infiltrating immune cells, which includes CD4+T cells, CD8+T cells, B cells, and natural killer cells (NK) in various tumors. Furthermore, SLC35A2 expression was significantly correlated with pan-cancer immune checkpoints, TMB, MSI, and TIDE genes. SLC35A2 showed significant predictive value for the immunotherapy response of patients with diverse cancers. Two drugs, vismodegib and abiraterone, were identified, and the free binding energy of cytochrome P17 with abiraterone was higher than that of SLC35A2 with abiraterone. Conclusion: Our study revealed that SLC35A2 is upregulated in 20 types of cancer, including lung adenocarcinoma (LUAD), breast invasive carcinoma (BRCA), colon adenocarcinoma (COAD), and lung squamous cell carcinoma (LUSC). The upregulated SLC35A2 in five cancer types indicates a poor prognosis. Furthermore, there was a positive correlation between the overexpression of SLC35A2 and reduced lymphocyte infiltration in 13 cancer types, including BRCA and COAD. Based on data from several clinical trials, patients with LUAD, LUSC, SKCM, and BLCA who exhibited high SLC35A2 expression may experience improved immunotherapy response. Therefore, SLC35A2 could be considered a potential predictive biomarker for the prognosis and immunotherapy efficacy of various tumors. Our study provides a theoretical basis for further investigating its prognostic and therapeutic potentials.


Assuntos
Biomarcadores Tumorais , Proteínas de Transporte de Monossacarídeos , Neoplasias , Humanos , Expressão Gênica , Imunoterapia , Proteínas de Transporte de Monossacarídeos/genética , Mutação , Neoplasias/genética , Neoplasias/imunologia , Neoplasias/terapia , Prognóstico , Linfócitos T/imunologia , Resultado do Tratamento , Microambiente Tumoral , Regulação para Cima , Biomarcadores Tumorais/genética
20.
JAMA Netw Open ; 6(5): e2312231, 2023 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-37155167

RESUMO

Importance: Newborn genome sequencing (NBSeq) can detect infants at risk for treatable disorders currently undetected by conventional newborn screening. Despite broad stakeholder support for NBSeq, the perspectives of rare disease experts regarding which diseases should be screened have not been ascertained. Objective: To query rare disease experts about their perspectives on NBSeq and which gene-disease pairs they consider appropriate to evaluate in apparently healthy newborns. Design, Setting, and Participants: This survey study, designed between November 2, 2021, and February 11, 2022, assessed experts' perspectives on 6 statements related to NBSeq. Experts were also asked to indicate whether they would recommend including each of 649 gene-disease pairs associated with potentially treatable conditions in NBSeq. The survey was administered between February 11 and September 23, 2022, to 386 experts, including all 144 directors of accredited medical and laboratory genetics training programs in the US. Exposures: Expert perspectives on newborn screening using genome sequencing. Main Outcomes and Measures: The proportion of experts indicating agreement or disagreement with each survey statement and those who selected inclusion of each gene-disease pair were tabulated. Exploratory analyses of responses by gender and age were conducted using t and χ2 tests. Results: Of 386 experts invited, 238 (61.7%) responded (mean [SD] age, 52.6 [12.8] years [range 27-93 years]; 126 [52.9%] women and 112 [47.1%] men). Among the experts who responded, 161 (87.9%) agreed that NBSeq for monogenic treatable disorders should be made available to all newborns; 107 (58.5%) agreed that NBSeq should include genes associated with treatable disorders, even if those conditions were low penetrance; 68 (37.2%) agreed that actionable adult-onset conditions should be sequenced in newborns to facilitate cascade testing in parents, and 51 (27.9%) agreed that NBSeq should include screening for conditions with no established therapies or management guidelines. The following 25 genes were recommended by 85% or more of the experts: OTC, G6PC, SLC37A4, CYP11B1, ARSB, F8, F9, SLC2A1, CYP17A1, RB1, IDS, GUSB, DMD, GLUD1, CYP11A1, GALNS, CPS1, PLPBP, ALDH7A1, SLC26A3, SLC25A15, SMPD1, GATM, SLC7A7, and NAGS. Including these, 42 gene-disease pairs were endorsed by at least 80% of experts, and 432 genes were endorsed by at least 50% of experts. Conclusions and Relevance: In this survey study, rare disease experts broadly supported NBSeq for treatable conditions and demonstrated substantial concordance regarding the inclusion of a specific subset of genes in NBSeq.


Assuntos
Condroitina Sulfatases , Doenças Raras , Masculino , Adulto , Humanos , Recém-Nascido , Feminino , Pessoa de Meia-Idade , Idoso , Idoso de 80 Anos ou mais , Doenças Raras/diagnóstico , Doenças Raras/genética , Triagem Neonatal , Pais , Sistema y+L de Transporte de Aminoácidos , Proteínas de Transporte de Monossacarídeos , Antiporters
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...