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1.
J Pharmacol Exp Ther ; 390(1): 99-107, 2024 Jun 21.
Artículo en Inglés | MEDLINE | ID: mdl-38670801

RESUMEN

Dotinurad was developed as a uricosuric agent, inhibiting urate (UA) reabsorption through the UA transporter URAT1 in the kidneys. Due to its high selectivity for URAT1 among renal UA transporters, we investigated the mechanism underlying this selectivity by identifying dotinurad binding sites specific to URAT1. Dotinurad was docked to URAT1 using AutoDock4, utilizing the AlphaFold2-predicted structure. The inhibitory effects of dotinurad on wild-type and mutated URAT1 at the predicted binding sites were assessed through URAT1-mediated [14C]UA uptake in Xenopus oocytes. Nine amino acid residues in URAT1 were identified as dotinurad-binding sites. Sequence alignment with UA-transporting organic anion transporters (OATs) revealed that H142 and R487 were unique to URAT1 among renal UA-transporting OATs. For H142, IC50 values of dotinurad increased to 62, 55, and 76 nM for mutated URAT1 (H142A, H142E, and H142R, respectively) compared with 19 nM for the wild type, indicating that H142 contributes to URAT1-selective interaction with dotinurad. H142 was predicted to interact with the phenyl-hydroxyl group of dotinurad. The IC50 of the hydroxyl group methylated dotinurad (F13141) was 165 µM, 8420-fold higher than dotinurad, suggesting the interaction of H142 and the phenyl-hydroxyl group by forming a hydrogen bond. Regarding R487, URAT1-R487A exhibited a loss of activity. Interestingly, the URAT1-H142A/R487A double mutant restored UA transport activity, with the IC50 value of dotinurad for the mutant (388 nM) significantly higher than that for H142A (73.5 nM). These results demonstrate that H142 and R487 of URAT1 determine its selectivity for dotinurad, a uniqueness observed only in URAT1 among UA-transporting OATs. SIGNIFICANCE STATEMENT: Dotinurad selectively inhibits the urate reabsorption transporter URAT1 in renal urate-transporting organic ion transporters (OATs). This study demonstrates that dotinurad interacts with H142 and R487 of URAT1, located in the extracellular domain and unique among OATs when aligning amino acid sequences. Mutations in these residues reduce affinity of dotinurad for URAT1, confirming their role in conferring selective inhibition. Additionally, the interaction between dotinurad and URAT1 involving H142 is found to mediate hydrogen bonding.


Asunto(s)
Transportadores de Anión Orgánico , Ácido Úrico , Uricosúricos , Animales , Transportadores de Anión Orgánico/metabolismo , Transportadores de Anión Orgánico/antagonistas & inhibidores , Transportadores de Anión Orgánico/genética , Ácido Úrico/metabolismo , Ácido Úrico/farmacología , Sitios de Unión , Humanos , Uricosúricos/farmacología , Proteínas de Transporte de Catión Orgánico/metabolismo , Proteínas de Transporte de Catión Orgánico/genética , Proteínas de Transporte de Catión Orgánico/antagonistas & inhibidores , Xenopus laevis , Riñón/metabolismo , Riñón/efectos de los fármacos , Oocitos/metabolismo , Oocitos/efectos de los fármacos , Benzotiazoles/farmacología , Simulación del Acoplamiento Molecular
2.
Rinsho Shinkeigaku ; 63(12): 799-805, 2023 Dec 19.
Artículo en Japonés | MEDLINE | ID: mdl-37989290

RESUMEN

Biological phase separation refers to the liquid-liquid phase separation of biomolecules such as proteins in cells. Phase separation is driven by low-complexity domains of phase-separating proteins and strictly controlled by regulatory factors. Phase separation has also been found to be disrupted by genetic abnormalities. Abnormal aggregates of causative proteins accumulate in many neuromuscular diseases. In recent years, it has become clear that phase separating proteins are associated with neuromuscular diseases, and that abnormalities in the regulation of phase separation leads to the formation of aggregates. Gains in our knowledge of biological phase separation is gradually elucidating the pathogenesis of neuromuscular diseases.


Asunto(s)
Enfermedades Neuromusculares , Separación de Fases , Humanos
3.
Front Microbiol ; 13: 1053078, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36532476

RESUMEN

Mutation-driven evolution of novel function on an old gene has been documented in many development- and adaptive immunity-related genes but is poorly understood in immune effector molecules. Drosomycin-type antifungal peptides (DTAFPs) are a family of defensin-type effectors found in plants and ecdysozoans. Their primitive function was to control fungal infection and then co-opted for fighting against bacterial infection in plants, insects, and nematodes. This provides a model to study the structural and evolutionary mechanisms behind such functional diversification. In the present study, we determined the solution structure of mehamycin, a DTAFP from the Northern root-knot nematode Meloidogyne hapla with antibacterial activity and an 18-mer insert, and studied the mutational effect through using a mutant with the insert deleted. Mehamycin adopts an expected cysteine-stabilized α-helix and ß-sheet fold in its core scaffold and the inserted region, called single Disulfide Bridge-linked Domain (abbreviated as sDBD), forms an extended loop protruding from the scaffold. The latter folds into an amphipathic architecture stabilized by one disulfide bridge, which likely confers mehamycin a bacterial membrane permeability. Deletion of the sDBD remarkably decreased the ability but accompanying an increase in thermostability, indicative of a structure-function trade-off in the mehamycin evolution. Allosteric analysis revealed an interior interaction between the two domains, which might promote point mutations at some key sites of the core domain and ultimately give rise to the emergence of antibacterial function. Our work may be valuable in guiding protein engineering of mehamycin to improve its activity and stability.

4.
Front Cell Dev Biol ; 10: 750829, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35399536

RESUMEN

Proline:arginine (PR) poly-dipeptides from the GGGGCC repeat expansion in C9orf72 have cytotoxicity and bind intermediate filaments (IFs). However, it remains unknown how PR poly-dipeptides affect cytoskeletal organization and focal adhesion (FA) formation. Here, we show that changes to the cytoskeleton and FA by PR poly-dipeptides result in the alteration of cell stiffness and mechanical stress response. PR poly-dipeptides increased the junctions and branches of the IF network and increased cell stiffness. They also changed the distribution of actin filaments and increased the size of FA and intracellular calcium concentration. PR poly-dipeptides or an inhibitor of IF organization prevented cell detachment. Furthermore, PR poly-dipeptides induced upregulation of mechanical stress response factors and led to a maladaptive response to cyclic stretch. These results suggest that the effects of PR poly-dipeptides on mechanical properties and mechanical stress response may serve as a pathogenesis of C9orf72-related neurodegeneration.

5.
ACS Nano ; 16(1): 885-896, 2022 Jan 25.
Artículo en Inglés | MEDLINE | ID: mdl-34978188

RESUMEN

Rapid and efficient isolation of intact lysosomes is necessary to study their functions and metabolites by proteomic analysis. We developed a swift and robust nanoparticle-based magnetic separation method in which magnetic-plasmonic hybrid nanoparticles (MPNPs) conjugated with amino dextran (aDxt) were targeted to the lumen of lysosomes via the endocytosis pathway. For well-directed magnetic separation of the lysosomes, it is important to trace the intracellular trafficking of the aDxt-conjugated MPNPs (aDxt-MPNPs) in the endocytosis pathway. Therefore, we analyzed the intracellular transport process of the aDxt-MPNPs by investigating the time-dependent colocalization of plasmonic scattering of aDxt-MPNPs and immunostained marker proteins of organelles using the threshold Manders' colocalization coefficient (Rt). Detailed analysis of time variations of Rt for early and late endosomes and lysosomes allowed us to derive the transport kinetics of aDxt-MPNPs in a cell. After confirming the incubation time required for sufficient accumulation of aDxt-MPNPs in lysosomes, the lysosomes were magnetically isolated as intact as possible. By varying the elapsed time from homogenization to complete isolation of lysosomes (tdelay) and temperature (T), the influences of tdelay and T on the protein composition of the lysosomes were investigated by polyacrylamide gel electrophoresis and amino acid analysis. We found that the intactness of lysosomes could become impaired quite quickly, and to isolate lysosomes as intact as possible with high purity, tdelay = 30 min and T = 4 °C were optimal settings.


Asunto(s)
Endocitosis , Nanopartículas , Proteómica , Lisosomas/metabolismo , Endosomas/química , Fenómenos Magnéticos
6.
Mol Cell Proteomics ; 21(5): 100206, 2022 05.
Artículo en Inglés | MEDLINE | ID: mdl-35085786

RESUMEN

Membrane proteins play essential roles in various cellular processes, such as nutrient transport, bioenergetic processes, cell adhesion, and signal transduction. Proteomics is one of the key approaches to exploring membrane proteins comprehensively. Bottom-up proteomics using LC-MS/MS has been widely used in membrane proteomics. However, the low abundance and hydrophobic features of membrane proteins, especially integral membrane proteins, make it difficult to handle the proteins and are the bottleneck for identification by LC-MS/MS. Herein, to improve the identification and quantification of membrane proteins, we have stepwisely evaluated methods of membrane enrichment for the sample preparation. The enrichment methods of membranes consisted of precipitation by ultracentrifugation and treatment by urea or alkaline solutions. The best enrichment method in the study, washing with urea after isolation of the membranes, resulted in the identification of almost twice as many membrane proteins compared with samples without the enrichment. Notably, the method significantly enhances the identified numbers of multispanning transmembrane proteins, such as solute carrier transporters, ABC transporters, and G-protein-coupled receptors, by almost sixfold. Using this method, we revealed the profiles of amino acid transport systems with the validation by functional assays and found more protein-protein interactions, including membrane protein complexes and clusters. Our protocol uses standard procedures in biochemistry, but the method was efficient for the in-depth analysis of membrane proteome in a wide range of samples.


Asunto(s)
Proteínas de la Membrana , Proteómica , Cromatografía Liquida/métodos , Proteínas de la Membrana/metabolismo , Proteoma/metabolismo , Proteómica/métodos , Espectrometría de Masas en Tándem/métodos , Urea
7.
Plant Foods Hum Nutr ; 77(1): 90-97, 2022 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-35088214

RESUMEN

Betalain pigments are mainly produced by plants belonging to the order of Caryophyllales. Betalains exhibit strong antioxidant activity and responds to environmental stimuli and stress in plants. Recent reports of antioxidant, anti-inflammatory and anti-cancer properties of betalain pigments have piqued interest in understanding their biological functions. We investigated the effects of betalain pigments (betanin and isobetanin) derived from red-beet on amyloid-ß (Aß) aggregation, which causes Alzheimer's disease. Non-specific inhibition of Aß aggregation against Aß40 and Aß42 by red-beet betalain pigments, in vitro was demonstrated using the thioflavin t fluorescence assay, circular dichroism spectroscopy analysis, transmission electron microscopy and nuclear magnetic resonance (NMR) analysis. Furthermore, we examined the ability of red-beet betalain pigments to interfere with Aß toxicity by using the transgenic Caenorhabditis elegans model, which expresses the human Aß42 protein intracellularly within the body wall muscle. It responds to Aß-toxicity with paralysis and treatment with 50 µM red-beet betalain pigments significantly delayed the paralysis of C. elegans. These results suggest that betalain pigments reduce Aß-induced toxicity.


Asunto(s)
Beta vulgaris , Betalaínas , Péptidos beta-Amiloides/química , Péptidos beta-Amiloides/metabolismo , Péptidos beta-Amiloides/toxicidad , Animales , Antioxidantes/farmacología , Beta vulgaris/química , Betalaínas/análisis , Betalaínas/química , Betalaínas/farmacología , Caenorhabditis elegans/metabolismo , Parálisis/inducido químicamente
8.
J Biol Chem ; 297(6): 101370, 2021 12.
Artículo en Inglés | MEDLINE | ID: mdl-34756891

RESUMEN

Fungal plant pathogens secrete virulence-related proteins, called effectors, to establish host infection; however, the details are not fully understood yet. Functional screening of effector candidates using Agrobacterium-mediated transient expression assay in Nicotiana benthamiana identified two virulence-related effectors, named SIB1 and SIB2 (Suppression of Immunity in N. benthamiana), of an anthracnose fungus Colletotrichum orbiculare, which infects both cucurbits and N. benthamiana. The Agrobacterium-mediated transient expression of SIB1 or SIB2 increased the susceptibility of N. benthamiana to C. orbiculare, which suggested these effectors can suppress immune responses in N. benthamiana. The presence of SIB1 and SIB2 homologs was found to be limited to the genus Colletotrichum. SIB1 suppressed both (i) the generation of reactive oxygen species triggered by two different pathogen-associated molecular patterns, chitin and flg22, and (ii) the cell death response triggered by the Phytophthora infestans INF1 elicitin in N. benthamiana. We determined the NMR-based structure of SIB1 to obtain its structural insights. The three-dimensional structure of SIB1 comprises five ß-strands, each containing three disulfide bonds. The overall conformation was found to be a cylindrical shape, such as the well-known antiparallel ß-barrel structure. However, the ß-strands were found to display a unique topology, one pair of these ß-strands formed a parallel ß-sheet. These results suggest that the effector SIB1 present in Colletotrichum fungi has unique structural features and can suppress pathogen-associated molecular pattern-triggered immunity in N. benthamiana.


Asunto(s)
Colletotrichum/metabolismo , Proteínas Fúngicas/fisiología , Inmunidad de la Planta/fisiología , Agrobacterium/patogenicidad , Secuencia de Aminoácidos , Colletotrichum/patogenicidad , Proteínas Fúngicas/química , Interacciones Huésped-Patógeno , Conformación Proteica , Especies Reactivas de Oxígeno/metabolismo , Homología de Secuencia de Aminoácido , Nicotiana/metabolismo , Nicotiana/microbiología , Virulencia
9.
Mol Biol Evol ; 38(11): 5175-5189, 2021 10 27.
Artículo en Inglés | MEDLINE | ID: mdl-34320203

RESUMEN

Antimicrobial peptides (AMPs) have been considered as the alternatives to antibiotics because of their less susceptibility to microbial resistance. However, compared with conventional antibiotics they show relatively low activity and the consequent high cost and nonspecific cytotoxicity, hindering their clinical application. What's more, engineering of AMPs is a great challenge due to the inherent complexity in their sequence, structure, and function relationships. Here, we report an evolution-based strategy for improving the antifungal activity of a nematode-sourced defensin (Cremycin-5). This strategy utilizes a sequence-activity comparison between Cremycin-5 and its functionally diverged paralogs to identify sites associated with antifungal activity for screening of enhanceable activity-modulating sites for subsequent saturation mutagenesis. Using this strategy, we identified a site (Glu-15) whose mutations with nearly all other types of amino acids resulted in a universally enhanced activity against multiple fungal species, which is thereby defined as a Universally Enhanceable Activity-Modulating Site (UEAMS). Especially, Glu15Lys even exhibited >9-fold increased fungicidal potency against several clinical isolates of Candida albicans through inhibiting cytokinesis. This mutant showed high thermal and serum stability and quicker killing kinetics than clotrimazole without detectable hemolysis. Molecular dynamic simulations suggest that the mutations at the UEAMS likely limit the conformational flexibility of a distant functional residue via allostery, enabling a better peptide-fungus interaction. Further sequence, structural, and mutational analyses of the Cremycin-5 ortholog uncover an epistatic interaction between the UEAMS and another site that may constrain its evolution. Our work lights one new road to success of engineering AMP drug leads.


Asunto(s)
Antifúngicos , Candida albicans , Antifúngicos/farmacología , Candida albicans/genética , Pruebas de Sensibilidad Microbiana , Péptidos , Ingeniería de Proteínas
10.
Sci Rep ; 11(1): 9923, 2021 05 10.
Artículo en Inglés | MEDLINE | ID: mdl-33972675

RESUMEN

A model legume, Medicago truncatula, has over 600 nodule-specific cysteine-rich (NCR) peptides required for symbiosis with rhizobia. Among them, NCR169, an essential factor for establishing symbiosis, has four cysteine residues that are indispensable for its function. However, knowledge of NCR169 structure and mechanism of action is still lacking. In this study, we solved two NMR structures of NCR169 caused by different disulfide linkage patterns. We show that both structures have a consensus C-terminal ß-sheet attached to an extended N-terminal region with dissimilar features; one moves widely, whereas the other is relatively stapled. We further revealed that the disulfide bonds of NCR169 contribute to its structural stability and solubility. Regarding the function, one of the NCR169 oxidized forms could bind to negatively charged bacterial phospholipids. Furthermore, the positively charged lysine-rich region of NCR169 may be responsible for its antimicrobial activity against Escherichia coli and Sinorhizobium meliloti. This active region was disordered even in the phospholipid bound state, suggesting that the disordered conformation of this region is key to its function. Morphological observations suggested the mechanism of action of NCR169 on bacteria. The present study on NCR169 provides new insights into the structure and function of NCR peptides.


Asunto(s)
Antiinfecciosos/farmacología , Péptidos Catiónicos Antimicrobianos/farmacología , Medicago truncatula/inmunología , Proteínas de Plantas/farmacología , Antiinfecciosos/inmunología , Antiinfecciosos/aislamiento & purificación , Antiinfecciosos/metabolismo , Péptidos Catiónicos Antimicrobianos/inmunología , Péptidos Catiónicos Antimicrobianos/aislamiento & purificación , Péptidos Catiónicos Antimicrobianos/metabolismo , Escherichia coli/efectos de los fármacos , Medicago truncatula/metabolismo , Medicago truncatula/microbiología , Pruebas de Sensibilidad Microbiana , Proteínas de Plantas/inmunología , Proteínas de Plantas/aislamiento & purificación , Proteínas de Plantas/metabolismo , Proteínas Recombinantes/inmunología , Proteínas Recombinantes/aislamiento & purificación , Proteínas Recombinantes/metabolismo , Proteínas Recombinantes/farmacología , Rizosfera , Sinorhizobium meliloti/efectos de los fármacos
12.
Biochem Biophys Res Commun ; 520(3): 640-644, 2019 12 10.
Artículo en Inglés | MEDLINE | ID: mdl-31627896

RESUMEN

Two mGluR7-derived peptides corresponding to residues 856 to 879 and 856 to 875 are known to bind to Ca2+-saturated calmodulin (Ca2+/CaM), and their binding manners are thought to differ. Met872 function is believed as one of the anchor residues for CaM-binding only in the shorter peptide. To uncover the role of Met872 in CaM-binding, we prepared a mutant of the long peptide, mGluR7 (M872A), in which Met872 was replaced with Ala. We used the mutant together with the two peptides to perform NMR-titration experiments to monitor interaction with stable isotope-labeled CaM. Interaction of Ca2+/CaM with mGluR7 (M872A) caused a spectrum that differed from that of Ca2+/CaM with the long peptide, suggesting that Met872 of mGluR7 could be involved in CaM-binding even in the long peptide. Analyses of all NMR data suggested that the binding between Ca2+/CaM and mGluR7 occurs in some conformational equilibrium manner. The unique CaM-binding properties caused by Met872 may be related to mGluR7's function.


Asunto(s)
Calmodulina/metabolismo , Receptores de Glutamato Metabotrópico/química , Receptores de Glutamato Metabotrópico/metabolismo , Secuencia de Aminoácidos , Sustitución de Aminoácidos , Animales , Proteínas Aviares/metabolismo , Sitios de Unión/genética , Calcio/metabolismo , Pollos , Técnicas In Vitro , Metionina/química , Mutagénesis Sitio-Dirigida , Resonancia Magnética Nuclear Biomolecular , Unión Proteica , Ratas , Receptores de Glutamato Metabotrópico/genética , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo
13.
Biochem Biophys Res Commun ; 514(3): 803-808, 2019 06 30.
Artículo en Inglés | MEDLINE | ID: mdl-31079920

RESUMEN

Nuclear magnetic resonance (NMR) data directly indicated a Ca2+-dependent interaction between calmodulin (CaM) and CoDN3, a small effector of the plant pathogenic fungus Colletotrichum orbiculare, which is the causal agent of cucumber anthracnose. The overall conformation of CoDN3 is intrinsically disordered, and the CaM-binding site spans residues 34-53 of its C-terminal region. Experiments employing a chemically synthesized peptide corresponding to the CaM-binding site indicated that the CaM-binding region of CoDN3 in the Ca2+-bound CaM complex takes an α-helical conformation. Cell death suppression assay using a CoDN3 mutant lacking the CaM-binding ability suggested that the wild type CaM-binding site is necessary for full CoDN3 function in vivo.


Asunto(s)
Calmodulina/metabolismo , Colletotrichum/metabolismo , Proteínas Fúngicas/metabolismo , Secuencia de Aminoácidos , Proteínas Fúngicas/química , Mutación/genética , Unión Proteica , Espectroscopía de Protones por Resonancia Magnética
14.
Plant Biotechnol J ; 17(5): 969-981, 2019 05.
Artículo en Inglés | MEDLINE | ID: mdl-30451369

RESUMEN

Betalains are plant pigments primarily produced by plants of the order Caryophyllales. Because betalain possesses anti-inflammatory and anticancer activities, it may be useful as a pharmaceutical agent and dietary supplement. Recent studies have identified the genes involved in the betalain biosynthesis of betanin. Amaranthin and celosianin II are abundant in the quinoa (Chenopodium quinoa Willd.) hypocotyl, and amaranthin comprises glucuronic acid bound to betanin; therefore, this suggests the existence of a glucuronyltransferase involved in the synthesis of amaranthin in the quinoa hypocotyl. To identify the gene involved in amaranthin biosynthesis, we performed a BLAST analysis and phylogenetic tree analysis based on sequences homologous to flavonoid glycosyltransferase, followed by expression analysis on the quinoa hypocotyl to obtain three candidate proteins. Production of amaranthin in a transient Nicotiana benthamiana expression system was evaluated for these candidates and one was identified as having the ability to produce amaranthin. The gene encoding this protein was quinoa amaranthin synthetase 1 (CqAmaSy1). We also created a transgenic tobacco bright yellow-2 (BY-2) cell line wherein four betalain biosynthesis genes were introduced to facilitate amaranthin production. This transgenic cell line produced 13.67 ± 4.13 µm (mean ± SEM) amaranthin and 26.60 ± 1.53 µm betanin, whereas the production of isoamaranthin and isobetanin could not be detected. Tests confirmed the ability of amaranthin and betanin to slightly suppress cancer cell viability. Furthermore, amaranthin was shown to significantly inhibit HIV-1 protease activity, whereas betanin did not.


Asunto(s)
Betacianinas/biosíntesis , Chenopodium quinoa/enzimología , Ligasas/aislamiento & purificación , Nicotiana/metabolismo , Proteínas de Plantas/aislamiento & purificación , Betacianinas/metabolismo , Reactores Biológicos , Células Cultivadas , Chenopodium quinoa/metabolismo , Clonación Molecular , Proteasa del VIH , Inhibidores de la Proteasa del VIH/metabolismo , Inhibidores de la Proteasa del VIH/farmacología , Ligasas/metabolismo , Redes y Vías Metabólicas , Proteínas de Plantas/metabolismo , Plantas Modificadas Genéticamente , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Nicotiana/citología , Nicotiana/enzimología
15.
Kidney Int ; 92(6): 1356-1369, 2017 12.
Artículo en Inglés | MEDLINE | ID: mdl-28754554

RESUMEN

Carnitine/organic cation transporter 1 (OCTN1) is a specific transporter of the food-derived antioxidant ergothioneine. Ergothioneine is absorbed by intestinal OCTN1, distributed through the bloodstream, and incorporated into each organ by OCTN1. OCTN1 expression is upregulated in injured tissues, and promotes ergothioneine uptake to reduce further damage caused by oxidative stress. However, the role of the OCTN1-ergothioneine axis in kidney-intestine cross-talk and chronic kidney disease (CKD) progression remains unclear. Here we assessed ergothioneine uptake via intestinal OCTN1 and confirmed the expression of OCTN1. The ability of OCTN1 to absorb ergothioneine was diminished in mice with CKD. In combination with OCTN1 dysfunction, OCTN1 localization on the intestinal apical cellular membrane was disturbed in mice with CKD. Proteomic analysis, RT-PCR, Western blotting, and immunohistochemistry revealed that PDZ (PSD95, Dlg, and ZO1), a PDZK1 domain-containing protein that regulates the localization of transporters, was decreased in mice with CKD. Decreased intestinal ergothioneine uptake from food decreased ergothioneine levels in the blood of mice with CKD. Despite increased OCTN1 expression and ergothioneine uptake into the kidneys of mice with CKD, ergothioneine levels did not increase. To identify the role of the OCTN1-ergothioneine axis in CKD, we evaluated kidney damage and oxidative stress in OCTN1-knockout mice with CKD and found that kidney fibrosis worsened. Oxidative stress indicators were increased in OCTN1-knockout mice. Moreover, ergothioneine levels in the blood of patients with CKD decreased, which were restored after kidney transplantation. Thus, a novel inter-organ interaction mediated by transporters is associated with CKD progression.


Asunto(s)
Antioxidantes/metabolismo , Proteínas Portadoras/metabolismo , Ergotioneína/metabolismo , Mucosa Intestinal/metabolismo , Péptidos y Proteínas de Señalización Intracelular/metabolismo , Proteínas de la Membrana/metabolismo , Insuficiencia Renal Crónica/patología , Animales , Transporte Biológico , Proteínas Portadoras/genética , Línea Celular , Membrana Celular/metabolismo , Modelos Animales de Enfermedad , Progresión de la Enfermedad , Regulación hacia Abajo , Ergotioneína/sangre , Humanos , Intestinos/citología , Túbulos Renales/citología , Túbulos Renales/patología , Masculino , Proteínas de la Membrana/genética , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Proteínas de Transporte de Catión Orgánico , Estrés Oxidativo , Insuficiencia Renal Crónica/sangre , Simportadores , Regulación hacia Arriba
16.
Pharm Res ; 34(6): 1233-1243, 2017 06.
Artículo en Inglés | MEDLINE | ID: mdl-28361200

RESUMEN

PURPOSE: Monoamine oxidases (MAOs) are non-CYP enzymes that contribute to systemic elimination of therapeutic agents, and localized on mitochondrial membranes. The aim of the present study was to validate quantitative estimation of metabolic clearance of MAO substrate drugs using human liver microsomes (HLMs). METHODS: Three MAO substrate drugs, sumatriptan, rizatriptan and phenylephrine, as well as four CYP substrates were selected, and their disappearance during incubation with HLMs or mitochondria (HLMt) was measured. Metabolic clearance (CL) was then calculated from the disappearance curve. RESULTS: CL obtained in HLMs for sumatriptan and a typical MAO substrate serotonin was correlated with that obtained in HLMt among ten human individual livers. Hepatic intrinsic clearance (CLint,vitro) estimated from CL in HLMs was 14-20 and 2-5 times lower than in vivo hepatic intrinsic clearance (CLint,vivo) obtained from literature for MAO and CYP substrates, respectively. Utilization of HLMs for quantitatively assessing metabolic clearance of MAO substrates was further validated by proteomics approach which has revealed that numerous proteins localized on inner and outer membranes of mitochondria were detected in both HLMs and HLMt. CONCLUSION: CLint,vitro values of MAO substrate drugs can be quantitatively estimated with HLMs and could be used for semi-quantitative prediction of CLint,vivo values.


Asunto(s)
Microsomas Hepáticos/metabolismo , Monoaminooxidasa/metabolismo , Fenilefrina/metabolismo , Sumatriptán/metabolismo , Triazoles/metabolismo , Triptaminas/metabolismo , Humanos , Cinética , Tasa de Depuración Metabólica , Fenilefrina/farmacología , Sumatriptán/farmacología , Triazoles/farmacología , Triptaminas/farmacología
17.
J Biol Chem ; 292(11): 4469-4483, 2017 03 17.
Artículo en Inglés | MEDLINE | ID: mdl-28119455

RESUMEN

Obesity is closely associated with various metabolic disorders. However, little is known about abnormalities in the metabolic change of obese adipose tissue. Here we use static metabolic analysis and in vivo metabolic turnover analysis to assess metabolic dynamics in obese mice. The static metabolic analyses showed that glutamate and constitutive metabolites of the TCA cycle were increased in the white adipose tissue (WAT) of ob/ob and diet-induced obesity mice but not in the liver or skeletal muscle of these obese mice. Moreover, in vivo metabolic turnover analyses demonstrated that these glucose-derived metabolites were dynamically and specifically produced in obese WAT compared with lean WAT. Glutamate rise in obese WAT was associated with down-regulation of glutamate aspartate transporter (GLAST), a major glutamate transporter for adipocytes, and low uptake of glutamate into adipose tissue. In adipocytes, glutamate treatment reduced adiponectin secretion and insulin-mediated glucose uptake and phosphorylation of Akt. These data suggest that a high intra-adipocyte glutamate level potentially relates to adipocyte dysfunction in obesity. This study provides novel insights into metabolic dysfunction in obesity through comprehensive application of in vivo metabolic turnover analysis in two obese animal models.


Asunto(s)
Tejido Adiposo Blanco/metabolismo , Ciclo del Ácido Cítrico , Glutamatos/metabolismo , Metaboloma , Obesidad/metabolismo , Células 3T3-L1 , Animales , Dieta Alta en Grasa/efectos adversos , Glucosa/metabolismo , Hígado/metabolismo , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Obesos , Músculo Esquelético/metabolismo , Obesidad/etiología
18.
Eur J Neurosci ; 42(3): 1984-2002, 2015 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-26060893

RESUMEN

Stria vascularis of the mammalian cochlea transports K(+) to establish the electrochemical property in the endolymph crucial for hearing. This epithelial tissue also transports various small molecules. To clarify the profile of proteins participating in the transport system in the stria vascularis, membrane components purified from the stria of adult rats were analysed by liquid chromatography tandem mass spectrometry. Of the 3236 proteins detected in the analysis, 1807 were membrane proteins. Ingenuity Knowledge Base and literature data identified 513 proteins as being expressed on the 'plasma membrane', these included 25 ion channels and 79 transporters. Sixteen of the former and 62 of the latter had not yet been identified in the stria. Unexpectedly, many Cl(-) and Ca(2+) transport systems were found, suggesting that the dynamics of these ions play multiple roles. Several transporters for organic substances were also detected. Network analysis demonstrated that a few kinases, including protein kinase A, and Ca(2+) were key regulators for the strial transports. In the library of channels and transporters, 19 new candidates for uncloned deafness-related genes were identified. These resources provide a platform for understanding the molecular mechanisms underlying the epithelial transport essential for cochlear function and the pathophysiological processes involved in hearing disorders.


Asunto(s)
Sordera/fisiopatología , Proteínas de Transporte de Membrana/metabolismo , Estría Vascular/metabolismo , Animales , Bases de Datos Genéticas , Sordera/genética , Humanos , Masculino , Proteínas de Transporte de Membrana/genética , Ratones , Datos de Secuencia Molecular , Proteómica , Ratas
19.
Cell Biochem Biophys ; 69(1): 7-19, 2014 May.
Artículo en Inglés | MEDLINE | ID: mdl-24081810

RESUMEN

Calmodulin (CaM) binds to the FERM domain of 80 kDa erythrocyte protein 4.1R (R30) independently of Ca(2+) but, paradoxically, regulates R30 binding to transmembrane proteins in a Ca(2+)-dependent manner. We have previously mapped a Ca(2+)-independent CaM-binding site, pep11 (A(264)KKLWKVCVEHHTFFR), in 4.1R FERM domain and demonstrated that CaM, when saturated by Ca(2+) (Ca(2+)/CaM), interacts simultaneously with pep11 and with Ser(185) in A(181)KKLSMYGVDLHKAKD (pep9), the binding affinity of Ca(2+)/CaM for pep9 increasing dramatically in the presence of pep11. Based on these findings, we hypothesized that pep11 induced key conformational changes in the Ca(2+)/CaM complex. By differential scanning calorimetry analysis, we established that the C-lobe of CaM was more stable when bound to pep11 either in the presence or absence of Ca(2+). Using nuclear magnetic resonance spectroscopy, we identified 8 residues in the N-lobe and 14 residues in the C-lobe of pep11 involved in interaction with CaM in both of presence and absence of Ca(2+). Lastly, Kratky plots, generated by small-angle X-ray scattering analysis, indicated that the pep11/Ca(2+)/CaM complex adopted a relaxed globular shape. We propose that these unique properties may account in part for the previously described Ca(2+)/CaM-dependent regulation of R30 binding to membrane proteins.


Asunto(s)
Calcio/metabolismo , Calmodulina/química , Proteínas del Citoesqueleto/química , Proteínas de la Membrana/química , Péptidos/química , Secuencia de Aminoácidos , Animales , Sitios de Unión , Calmodulina/metabolismo , Cationes Bivalentes , Pollos , Proteínas del Citoesqueleto/metabolismo , Humanos , Proteínas de la Membrana/metabolismo , Simulación de Dinámica Molecular , Datos de Secuencia Molecular , Mapeo Peptídico , Péptidos/síntesis química , Unión Proteica , Dominios y Motivos de Interacción de Proteínas , Proteínas Recombinantes/química , Proteínas Recombinantes/metabolismo , Termodinámica
20.
Cell Biochem Biophys ; 66(3): 545-58, 2013 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-23354586

RESUMEN

Protein 4.1G (4.1G) is a widely expressed member of the protein 4.1 family of membrane skeletal proteins. We have previously reported that Ca(2+)-saturated calmodulin (Ca(2+)/CaM) modulates 4.1G interactions with transmembrane and membrane-associated proteins through binding to Four.one-ezrin-radixin-moesin (4.1G FERM) domain and N-terminal headpiece region (GHP). Here we identify a novel mechanism of Ca(2+)/CaM-mediated regulation of 4.1G interactions using a combination of small-angle X-ray scattering, nuclear magnetic resonance spectroscopy, and circular dichroism spectroscopy analyses. We document that GHP intrinsically disordered coiled structure switches to a stable compact structure upon binding of Ca(2+)/CaM. This dramatic conformational change of GHP inhibits in turn 4.1G FERM domain interactions due to steric hindrance. Based upon sequence homologies with the Ca(2+)/CaM-binding motif in protein 4.1R headpiece region, we establish that the 4.1G S(71)RGISRFIPPWLKKQKS peptide (pepG) mediates Ca(2+)/CaM binding. As observed for GHP, the random coiled structure of pepG changes to a relaxed globular shape upon complex formation with Ca(2+)/CaM. The resilient coiled structure of pepG, maintained even in the presence of trifluoroethanol, singles it out from any previously published CaM-binding peptide. Taken together, these results show that Ca(2+)/CaM binding to GHP, and more specifically to pepG, has profound effects on other functional domains of 4.1G.


Asunto(s)
Calcio/metabolismo , Calmodulina/metabolismo , Proteínas del Citoesqueleto/química , Proteínas del Citoesqueleto/metabolismo , Proteínas de la Membrana/química , Proteínas de la Membrana/metabolismo , Secuencia de Aminoácidos , Modelos Moleculares , Datos de Secuencia Molecular , Fragmentos de Péptidos/química , Fragmentos de Péptidos/metabolismo , Unión Proteica , Estructura Secundaria de Proteína , Estructura Terciaria de Proteína
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