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1.
Ther Drug Monit ; 2024 Apr 04.
Artigo em Inglês | MEDLINE | ID: mdl-38648649

RESUMO

BACKGROUND: Brexpiprazole is a second-generation antipsychotic approved in Japan in 2018; however, information on placental passage and breast milk transfer remains limited. In this report, the patient, a 30-year-old pregnant woman with schizophrenia, was medicated with brexpiprazole, risperidone, and quetiapine. METHODS: The study used high-performance liquid chromatography-tandem mass spectrometry to determine the concentrations of brexpiprazole, quetiapine, risperidone, and its active metabolite (paliperidone) in maternal and neonatal plasma, cord venous plasma, and breast milk. Maternal plasma samples were obtained approximately 2 and 8 hours after the last administration of antipsychotics on the day of delivery and at the estimated drugs' trough time on days 1, 3, and 5 after delivery. RESULTS: The maternal plasma concentrations of brexpiprazole, quetiapine, and paliperidone increased by approximately 3.5-fold on the fifth day compared with those on the day of delivery, whereas the risperidone concentration remained almost constant. Moreover, the neonatal plasma concentrations of the 4 drugs immediately after birth were indistinguishable from the umbilical cord concentrations and gradually decreased, except for risperidone. Relative infant doses of these compounds were below 1.1%. CONCLUSIONS: Pregnancy status notably alters the pharmacokinetic properties of antipsychotics. Therefore, close and careful monitoring of clinical symptoms should be considered during pregnancy and after delivery. Although brexpiprazole is transferred to neonates through the placenta, breastfeeding is still possible because the relative infant dose value of this drug was much less than 10%.

2.
Nat Commun ; 15(1): 455, 2024 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-38225262

RESUMO

mRNA export is an essential pathway for the regulation of gene expression. In humans, closely related RNA helicases, UAP56 and URH49, shape selective mRNA export pathways through the formation of distinct complexes, known as apo-TREX and apo-AREX complexes, and their subsequent remodeling into similar ATP-bound complexes. Therefore, defining the unidentified components of the apo-AREX complex and elucidating the molecular mechanisms underlying the formation of distinct apo-complexes is key to understanding their functional divergence. In this study, we identify additional apo-AREX components physically and functionally associated with URH49. Furthermore, by comparing the structures of UAP56 and URH49 and performing an integrated analysis of their chimeric mutants, we exhibit unique structural features that would contribute to the formation of their respective complexes. This study provides insights into the specific structural and functional diversification of these two helicases that diverged from the common ancestral gene Sub2.


Assuntos
RNA Helicases DEAD-box , RNA Helicases , Humanos , Transporte Ativo do Núcleo Celular , RNA Helicases DEAD-box/genética , RNA Helicases DEAD-box/metabolismo , RNA Helicases/metabolismo , Transporte de RNA , RNA Mensageiro/genética , RNA Mensageiro/metabolismo
3.
Nat Cell Biol ; 25(11): 1664-1675, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37932453

RESUMO

Many membraneless organelles (MLOs) formed through phase separation play crucial roles in various cellular processes. Although these MLOs co-exist in cells, how they maintain their independence without coalescence or engulfment remains largely unknown. Here, we investigated the molecular mechanism by which paraspeckles with core-shell architecture scaffolded by NEAT1_2 long noncoding RNAs exist as distinct MLOs. We identified NEAT1 deletion mutants that assemble paraspeckles that are incorporated into nuclear speckles. Several paraspeckle proteins, including SFPQ, HNRNPF and BRG1, prevent this incorporation and thus contribute to the segregation of paraspeckles from nuclear speckles. Shell localization of these proteins in the paraspeckles, which is determined by NEAT1_2 long noncoding RNA domains, is required for this segregation process. Conversely, U2-related spliceosomal proteins are involved in internalizing the paraspeckles into nuclear speckles. This study shows that the paraspeckle shell composition dictates the independence of MLOs in the nucleus, providing insights into the importance of the shell in defining features and functions of MLOs.


Assuntos
Núcleo Celular , RNA Longo não Codificante , Condensados Biomoleculares , Núcleo Celular/genética , Núcleo Celular/metabolismo , Paraspeckles , RNA Longo não Codificante/genética , RNA Longo não Codificante/metabolismo , Humanos
4.
Clin Transl Sci ; 16(4): 618-630, 2023 04.
Artigo em Inglês | MEDLINE | ID: mdl-36655374

RESUMO

This study aimed to determine the effects of pregnancy and ontogeny on risperidone and paliperidone pharmacokinetics by assessing their serum concentrations in two subjects and constructing a customized physiologically-based pharmacokinetic (PBPK) model. Risperidone and paliperidone serum concentrations were determined in a pregnant woman and her newborn. PBPK models for risperidone and paliperidone in adults, pediatric, and pregnant populations were developed and verified using the Simcyp simulator. These models were then applied to our two subjects, generating their "virtual twins." Effects of pregnancy on both drugs were examined using models with fixed pharmacokinetic parameters. In the neonatal PBPK simulation, 10 different models for estimating the renal function of neonates were evaluated. Risperidone was not detected in the serum of both pregnant woman and her newborn. Maternal and neonatal serum paliperidone concentrations were between 2.05-3.80 and 0.82-1.03 ng/ml, respectively. Developed PBPK models accurately predicted paliperidone's pharmacokinetics, as shown by minimal bias and acceptable precision across populations. The individualized maternal model predicted all observed paliperidone concentrations within the 90% prediction interval. Fixed-parameter simulations showed that CYP2D6 activity largely affects risperidone and paliperidone pharmacokinetics during pregnancy. The Flanders metadata equation showed the lowest absolute bias (mean error: 22.3% ± 6.0%) and the greatest precision (root mean square error: 23.8%) in predicting paliperidone plasma concentration in the neonatal population. Our constructed PBPK model can predict risperidone and paliperidone pharmacokinetics in pregnant and neonatal populations, which could help with precision dosing using the PBPK model-informed approach in special populations.


Assuntos
Palmitato de Paliperidona , Risperidona , Humanos , Adulto , Feminino , Gravidez , Criança , Recém-Nascido , Gestantes , Citocromo P-450 CYP2D6 , Modelos Biológicos
5.
Nucleic Acids Res ; 50(15): 8779-8806, 2022 08 26.
Artigo em Inglês | MEDLINE | ID: mdl-35902094

RESUMO

Recent in vitro reconstitution analyses have proven that the physical interaction between the exosome core and MTR4 helicase, which promotes the exosome activity, is maintained by either MPP6 or RRP6. However, knowledge regarding the function of MPP6 with respect to in vivo exosome activity remains scarce. Here, we demonstrate a facilitative function of MPP6 that composes a specific part of MTR4-dependent substrate decay by the human exosome. Using RNA polymerase II-transcribed poly(A)+ substrate accumulation as an indicator of a perturbed exosome, we found functional redundancy between RRP6 and MPP6 in the decay of these poly(A)+ transcripts. MTR4 binding to the exosome core via MPP6 was essential for MPP6 to exert its redundancy with RRP6. However, at least for the decay of our identified exosome substrates, MTR4 recruitment by MPP6 was not functionally equivalent to recruitment by RRP6. Genome-wide classification of substrates based on their sensitivity to each exosome component revealed that MPP6 deals with a specific range of substrates and highlights the importance of MTR4 for their decay. Considering recent findings of competitive binding to the exosome between auxiliary complexes, our results suggest that the MPP6-incorporated MTR4-exosome complex is one of the multiple alternative complexes rather than the prevailing one.


Assuntos
Exossomos , Proteínas de Membrana/metabolismo , Proteínas de Saccharomyces cerevisiae , Núcleo Celular/metabolismo , Complexo Multienzimático de Ribonucleases do Exossomo/metabolismo , Exossomos/metabolismo , Humanos , Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismo
6.
Int J Mol Sci ; 23(5)2022 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-35269695

RESUMO

Calcium homeostasis endoplasmic reticulum protein (CHERP) is colocalized with the inositol 1,4,5-trisphosphate receptor (IP3R) in the endoplasmic reticulum or perinuclear region, and has been involved in intracellular calcium signaling. Structurally, CHERP carries the nuclear localization signal and arginine/serine-dipeptide repeats, like domain, and interacts with the spliceosome. However, the exact function of CHERP in the nucleus remains unknown. Here, we showed that poly(A)+ RNAs accumulated in the nucleus of CHERP-depleted U2OS cells. Our global analysis revealed that CHERP regulated alternative mRNA splicing events by interaction with U2 small nuclear ribonucleoproteins (U2 snRNPs) and U2 snRNP-related proteins. Among the five alternative splicing patterns analyzed, intron retention was the most frequently observed event. This was in accordance with the accumulation of poly(A)+ RNAs in the nucleus. Furthermore, intron retention and cassette exon choices were influenced by the strength of the 5' or 3' splice site, the branch point site, GC content, and intron length. In addition, CHERP depletion induced anomalies in the cell cycle progression into the M phase, and abnormal cell division. These results suggested that CHERP is involved in the regulation of alternative splicing.


Assuntos
Processamento Alternativo , Precursores de RNA , Núcleo Celular/genética , Núcleo Celular/metabolismo , Precursores de RNA/genética , Precursores de RNA/metabolismo , Sítios de Splice de RNA , Splicing de RNA , Ribonucleoproteínas Nucleares Pequenas/genética , Spliceossomos/genética , Spliceossomos/metabolismo
7.
J Pharm Health Care Sci ; 7(1): 23, 2021 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-34193299

RESUMO

BACKGROUND: A multicenter investigation of neonate exposure to potentially harmful excipients (PHEs) in neonatal intensive care units (NICUs) in Japan has not been conducted. METHODS: A multicenter nationwide observational study was conducted. Neonate patient demographic data and information on all medicines prescribed and administered during hospitalization on 1 day between November 2019 and March 2021 were extracted from the medical records. Nine PHEs, paraben, polysorbate 80, propylene glycol, benzoates, saccharin sodium, sorbitol, ethanol, benzalkonium chloride, and aspartame, were selected. PHEs were identified from the package insert and the Interview Form. The quantitative daily exposure was calculated if quantitative data were available for each product containing the PHE. RESULTS: Prescription data was collected from 22 NICUs in Japan. In total, 343 neonates received 2360 prescriptions for 426 products containing 228 active pharmaceutical ingredients. PHEs were found in 52 (12.2%) products in 646 (27.4%) prescriptions for 282 (82.2%) neonates. Benzyl alcohol, sodium benzoates, and parabens were the most common PHEs in parenteral, enteral, and topical formulations, respectively. Quantitative analysis showed that 10 (10%), 38 (42.2%), 37 (94.9%), and 9 (39.1%) neonates received doses exceeding the acceptable daily intake of benzyl alcohol, polysorbate 80, propylene glycol, and sorbitol, respectively. However, due to the lack of quantitative information for all enteral and topical products, accurate daily PHE exposure could not be quantified. CONCLUSIONS: Neonates admitted to NICUs in Japan were exposed to PHEs, and several of the most commonly prescribed medicines in daily clinical practice in NICUs contained PHEs. Neonate PHE exposure could be reduced by replacing these medicines with available PHE-free alternatives.

8.
iScience ; 22: 336-352, 2019 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-31809999

RESUMO

Cancer cells often exhibit extreme sensitivity to splicing inhibitors. We identified food-derived flavonoids, apigenin and luteolin, as compounds that modulate mRNA splicing at the genome-wide level, followed by proliferation inhibition. They bind to mRNA splicing-related proteins to induce a widespread change of splicing patterns in treated cells. Their inhibitory activity on splicing is relatively moderate, and introns with weak splice sites tend to be sensitive to them. Such introns remain unspliced, and the resulting intron-containing mRNAs are retained in the nucleus, resulting in the nuclear accumulation of poly(A)+ RNAs in these flavonoid-treated cells. Tumorigenic cells are more susceptible to these flavonoids than nontumorigenic cells, both for the nuclear poly(A)+ RNA-accumulating phenotype and cell viability. This study illustrates the possible mechanism of these flavonoids to suppress tumor progression in vivo that were demonstrated by previous studies and provides the potential of daily intake of moderate splicing inhibitors to prevent cancer development.

9.
J Med Phys ; 44(1): 35-38, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30983769

RESUMO

PURPOSE: The purpose of this study is to build a system for effective dose display immediately after the gastric cancer X-ray screening. MATERIALS AND METHODS: The regression equation of effective dose and dose area product (DAP) was introduced from the data of 500 persons including DAP and effective dose calculated using program for X-ray Monte Carlo. RESULTS: The effective dose was 5.39 mSv of median, 1.18 mSv of minimum, and 38.38 mSv of maximum. The regression equation was Y=0.354+0.0003772X (Y: effective dose, mSv, X: DAP, mGy cm2). Using the regression equation, the effective dose can be estimated from DAP and displayed just after the individual screening. CONCLUSIONS: "Effective dose display system" was constructed to display effective dose immediately after gastric cancer X-ray screening. This system is on the way to be reformed by improving the regression equation on larger data.

10.
ChemSusChem ; 10(14): 2864-2868, 2017 07 21.
Artigo em Inglês | MEDLINE | ID: mdl-28544652

RESUMO

Here, we report remarkable oxygen evolution reaction (OER) catalytic activity of brownmillerite (BM)-type Ca2 FeCoO5 . The OER activity of this oxide is comparable to or beyond those of the state-of-the-art perovskite (PV)-catalyst Ba0.5 Sr0.5 Co0.8 Fe0.2 O3-δ (BSCF) and a precious-metal catalyst RuO2 , emphasizing the importance of the characteristic BM structure with multiple coordination environments of transition metal (TM) species. Also, Ca2 FeCoO5 is clearly advantageous in terms of expense/laboriousness of the material synthesis. These facts make this oxide a promising OER catalyst used in many energy conversion technologies such as metal-air secondary batteries and hydrogen production from electrochemical/photocatalytic water splitting.


Assuntos
Cobalto/química , Compostos de Ferro/química , Óxidos/química , Oxigênio/química , Catálise , Modelos Moleculares , Conformação Molecular
11.
Biosci Biotechnol Biochem ; 78(4): 609-13, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25036957

RESUMO

Phosphoenolpyruvate carboxylase (PEPC) undergoes activity regulation through reversible phosphorylation. The day/night phosphorylation of leaf PEPC in 27 C3 plant species was analyzed by immunoblotting. PEPC was phosphorylated in the daytime in 12 species, whereas it was phosphorylated at night in three species, rice, Monochoria vaginalis, and Sagittaria trifolia, all of which are hygrophytic monocots. Immunoblot analysis of isolated chloroplasts of M. vaginalis identified a PEPC protein inside the chloroplast in addition to cytosolic isozyme(s) as previously shown in genus Oryza. Using transgenic rice overexpressing the maize PEPC in the cytosol, we confirmed that the cytosolic PEPC underwent the nocturnal phosphorylation. These results suggest the interrelationship between the presence of chloroplastic PEPC and the nocturnal phosphorylation of cytosolic isozyme(s).


Assuntos
Magnoliopsida/metabolismo , Fosfoenolpiruvato Carboxilase/metabolismo , Folhas de Planta/metabolismo , Adaptação Fisiológica/efeitos dos fármacos , Cloroplastos/efeitos dos fármacos , Cloroplastos/metabolismo , Citosol/efeitos dos fármacos , Citosol/metabolismo , Magnoliopsida/citologia , Magnoliopsida/efeitos dos fármacos , Magnoliopsida/fisiologia , Fosforilação/efeitos dos fármacos , Folhas de Planta/efeitos dos fármacos , Especificidade da Espécie , Fatores de Tempo , Água/farmacologia
12.
J Am Chem Soc ; 136(19): 6790-3, 2014 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-24786634

RESUMO

High-surface-area N-decorated nanoporous carbons have been successfully synthesized using the N-rich metal-organic framework ZIF-8 as a template and precursor along with furfuryl alcohol and NH4OH as the secondary carbon and nitrogen sources, respectively. These carbons exhibited remarkable CO2 adsorption capacities and CO2/N2 and CO2/CH4 selectivities. The N-decoration in these carbons resulted in excellent activity for the oxygen reduction reaction. Samples NC900 and NC1000 having moderate N contents, high surface areas, and large numbers of mesopores favored the four-electron reduction pathway, while sample NC800 having a high N content, a moderate surface area, and a large number of micropores favored the two-electron reduction process.

13.
Mol Cell Biol ; 32(24): 4998-5008, 2012 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-23045394

RESUMO

Aft1p is an iron-responsive transcriptional activator that plays a central role in the regulation of iron metabolism in Saccharomyces cerevisiae. Aft1p is regulated by accelerated nuclear export in the presence of iron, mediated by Msn5p. However, the transcriptional activity of Aft1p is suppressed under iron-replete conditions in the Δmsn5 strain, although Aft1p remains in the nucleus. Aft1p dissociates from its target promoters under iron-replete conditions due to an interaction between Aft1p and the monothiol glutaredoxin Grx3p or Grx4p (Grx3/4p). The binding of Grx3/4p to Aft1p is induced by iron repletion and requires binding of an iron-sulfur cluster to Grx3/4p. The mitochondrial transporter Atm1p, which has been implicated in the export of iron-sulfur clusters and related molecules, is required not only for iron binding to Grx3p but also for dissociation of Aft1p from its target promoters. These results suggest that iron binding to Grx3p (and presumably Grx4p) is a prerequisite for the suppression of Aft1p. Since Atm1p plays crucial roles in the delivery of iron-sulfur clusters from the mitochondria to the cytoplasm and nucleus, these results support the previous observations that the mitochondrial iron-sulfur cluster assembly machinery is involved in cellular iron sensing.


Assuntos
Ferro/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Fatores de Transcrição/metabolismo , Transportadores de Cassetes de Ligação de ATP/genética , Transportadores de Cassetes de Ligação de ATP/metabolismo , Sítios de Ligação/genética , Expressão Gênica , Genes Fúngicos , Glutarredoxinas/genética , Glutarredoxinas/metabolismo , Proteínas Ferro-Enxofre/metabolismo , Carioferinas/genética , Carioferinas/metabolismo , Modelos Biológicos , Mutação , Oxirredutases/genética , Oxirredutases/metabolismo , Regiões Promotoras Genéticas , Transporte Proteico , Saccharomyces cerevisiae/crescimento & desenvolvimento , Proteínas de Saccharomyces cerevisiae/genética , Fatores de Transcrição/genética
14.
Chem Pharm Bull (Tokyo) ; 60(4): 562-70, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22466743

RESUMO

The reactions of (±)-α-epoxy drimenol (4) and (±)-α-epoxy drimenyl cyanide (6) with acids (proton acid or Lewis acid) selectively gave the rearranged aldehyde (±)-13 and (±)-15 having the hydroindane skeleton, respectively, while the reactions of (±)-4 and (±)-6 with Dibal-H selectively afforded the allyl alcohol (±)-14 and (±)-16, respectively. The reactions of (8aR)-6 and (8aS)-6 with Dibal-H were applied for the determination of the absolute structure of natural 7ß-acetoxy-ent-labda-8(17),13(14)E-dien-15-ol (18). The reaction of (±)-α-epoxy bicyclofarnesol (5) and (8aS)-5 with proton acid selectively provided the rearranged ketol (±)- and (8aS)-31 having the hydroindane skeleton, respectively. The optically active (8aS)-31 was converted to the natural (9S)-austrodoric acid (33).


Assuntos
Ácidos/química , Produtos Biológicos/síntese química , Compostos de Epóxi/química , Sesquiterpenos/química , Produtos Biológicos/química , Conformação Molecular , Sesquiterpenos Policíclicos , Estereoisomerismo
15.
Chem Commun (Camb) ; 48(36): 4353-5, 2012 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-22450541

RESUMO

A Rh porphyrin on carbon black was shown to catalyze the electro-oxidation of several aliphatic alcohols (ethanol, 1-propanol, and 2-propanol) and benzyl alcohols. The overpotentials for alcohol oxidation were very low. The reaction mechanism and substrate specificity are discussed.

16.
J Biotechnol ; 153(3-4): 86-91, 2011 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-21473891

RESUMO

Recent research into mRNA maturation processes in the nucleus has identified a number of proteins involved in mRNA transcription, capping, splicing, end processing and export. Among them, the Tap-p15 heterodimer acts as an mRNA export receptor. Tap-p15 is recruited onto fully processed mRNA in the nucleus, which is ready for export to the cytoplasm, through associating with Aly or SR proteins on mRNA, or by directly associating with a constitutive transport element (CTE), an RNA element derived from type D retroviruses. mRNA containing a CTE is exported to the cytoplasm by directly associating with Tap-p15, even in the absence of Tap-recruiting proteins such as Aly or SR proteins on the mRNA. Here, we showed that the use of a CTE enhanced the expression of recombinant protein in human cell lines. The co-expression of reporter proteins and Tap-p15 also enhanced recombinant protein expression. Moreover, the use of a CTE and Tap-p15 synergistically further enhanced the recombinant protein expression. In addition to Tap-p15, several Tap-p15-recruiting proteins, including Aly and SR proteins, enhanced recombinant protein expression, albeit independently of the CTE. The incorporation of a CTE and Tap-p15-recruiting proteins into protein expression system is useful to increase recombinant protein yield in human cells.


Assuntos
Proteínas de Transporte Nucleocitoplasmático/biossíntese , Engenharia de Proteínas/métodos , Transporte de RNA , Proteínas Recombinantes de Fusão/biossíntese , Sequências Reguladoras de Ácido Ribonucleico , Fosfatase Alcalina/biossíntese , Fosfatase Alcalina/química , Fosfatase Alcalina/genética , Western Blotting , Linhagem Celular Tumoral , Eritropoetina/biossíntese , Eritropoetina/química , Eritropoetina/genética , Humanos , Luciferases/biossíntese , Luciferases/química , Luciferases/genética , Proteínas de Transporte Nucleocitoplasmático/química , Proteínas de Transporte Nucleocitoplasmático/genética , Proteínas Recombinantes de Fusão/química , Proteínas Recombinantes de Fusão/genética
17.
Biosci Biotechnol Biochem ; 74(7): 1512-6, 2010.
Artigo em Inglês | MEDLINE | ID: mdl-20622428

RESUMO

Screening of mRNA export factors in Saccharomyces cerevisiae and Drosophila melanogaster has identified a number of mRNA processing factors involved in multiple mRNA processing steps. However, only limited information is available on human cells. Here we established a screening system searching for mRNA processing factors in human cells by combining the luciferase reporter system and fluorescence in situ hybridization, which evaluates the nuclear/cytoplasmic distribution of bulk poly(A)+ RNA. This system makes it possible to search for the compounds affecting mRNA processing from the various resources.


Assuntos
Genes Reporter/genética , Espaço Intracelular/metabolismo , Luciferases/genética , Poli A/metabolismo , Transporte de RNA , Células HeLa , Humanos , RNA Mensageiro/metabolismo
18.
Mol Biol Cell ; 21(16): 2953-65, 2010 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-20573985

RESUMO

Nuclear export of mRNA is an essential process for eukaryotic gene expression. The TREX complex couples gene expression from transcription and splicing to mRNA export. Sub2, a core component of the TREX complex in yeast, has diversified in humans to two closely related RNA helicases, UAP56 and URH49. Here, we show that URH49 forms a novel URH49-CIP29 complex, termed the AREX (alternative mRNA export) complex, whereas UAP56 forms the human TREX complex. The mRNAs regulated by these helicases are different at the genome-wide level. The two sets of target mRNAs contain distinct subsets of key mitotic regulators. Consistent with their target mRNAs, depletion of UAP56 causes mitotic delay and sister chromatid cohesion defects, whereas depletion of URH49 causes chromosome arm resolution defects and failure of cytokinesis. In addition, depletion of the other human TREX components or CIP29 causes mitotic defects similar to those observed in UAP56- or URH49-depleted cells, respectively. Taken together, the two closely related RNA helicases have evolved to form distinct mRNA export machineries, which regulate mitosis at different steps.


Assuntos
RNA Helicases DEAD-box/metabolismo , Mitose/fisiologia , RNA Mensageiro/metabolismo , Linhagem Celular Tumoral , Cromátides/genética , Aberrações Cromossômicas , Análise por Conglomerados , RNA Helicases DEAD-box/genética , Perfilação da Expressão Gênica , Células HeLa , Humanos , Immunoblotting , Imunoprecipitação , Hibridização in Situ Fluorescente , Mitose/genética , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Análise de Sequência com Séries de Oligonucleotídeos , Ligação Proteica , Interferência de RNA , Transporte de RNA , RNA Mensageiro/genética , Proteínas de Ligação a RNA/genética , Proteínas de Ligação a RNA/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo
19.
Chem Commun (Camb) ; 46(20): 3607-9, 2010 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-20379599

RESUMO

In this communication, we demonstrate that certain kinds of Rh porphyrins on carbon black can electrochemically oxidize aldose at low potentials. The onset potential was much lower than those with the other complex-based catalysts. A product analysis suggested that this reaction involves 2-electron oxidation of the aldehyde group.


Assuntos
Carboidratos/química , Metaloporfirinas/química , Ródio/química , Aldeídos/química , Catálise , Eletroquímica , Elétrons , Estrutura Molecular , Oxirredução , Estereoisomerismo
20.
J Biol Chem ; 284(45): 30798-806, 2009 Nov 06.
Artigo em Inglês | MEDLINE | ID: mdl-19759014

RESUMO

The majority of CDF/ZnT zinc transporters form homo-oligomers. However, ZnT5, ZnT6, and their orthologues form hetero-oligomers in the early secretory pathway where they load zinc onto zinc-requiring enzymes and maintain secretory pathway functions. The details of this hetero-oligomerization remain to be elucidated, and much more is known about homo-oligomerization that occurs in other CDF/ZnT family proteins. Here, we addressed this issue using co-immunoprecipitation experiments, mutagenesis, and chimera studies of hZnT5 and hZnT6 in chicken DT40 cells deficient in ZnT5, ZnT6, and ZnT7 proteins. We found that hZnT5 and hZnT6 combine to form heterodimers but do not form complexes larger than heterodimers. Mutagenesis of hZnT6 indicated that the sites present in transmembrane domains II and V in which many CDF/ZnT proteins have conserved hydrophilic amino acid residues are not involved in zinc binding of hZnT6, although they are required for zinc transport in other CDF/ZnT family homo-oligomers. We also found that the long N-terminal half of hZnT5 is not necessary for its functional interaction with hZnT6, whereas the cytosolic C-terminal tail of hZnT5 is important in determining hZnT6 as a partner molecule for heterodimer formation. In DT40 cells, cZnT5 variant lacking the N-terminal half was endogenously induced during periods of endoplasmic reticulum stress and so seemed to function to supply zinc to zinc-requiring enzymes under these conditions. The results outlined here provide new information about the mechanism of action through heterodimerization of CDF/ZnT proteins that function in the early secretory pathway.


Assuntos
Proteínas de Transporte de Cátions/química , Via Secretória , Motivos de Aminoácidos , Sequência de Aminoácidos , Animais , Proteínas de Transporte de Cátions/genética , Proteínas de Transporte de Cátions/metabolismo , Linhagem Celular , Galinhas , Dimerização , Humanos , Dados de Sequência Molecular , Ligação Proteica , Alinhamento de Sequência
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