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1.
Phys Rev Lett ; 132(7): 079901, 2024 Feb 16.
Artigo em Inglês | MEDLINE | ID: mdl-38427902

RESUMO

This corrects the article DOI: 10.1103/PhysRevLett.131.143201.

2.
Phys Rev Lett ; 131(14): 143201, 2023 Oct 06.
Artigo em Inglês | MEDLINE | ID: mdl-37862658

RESUMO

We have studied the desorption of positive ions from a LiF(110) crystal surface using positron and electron irradiation at 500 eV to examine the interaction between positrons and ionic crystals. Only monatomic ions, such as H^{+}, Li^{+}, and F^{+}, are detected under electron irradiation. However, positron irradiation leads to the significant desorption of ionic molecules, specifically, FH^{+} and F_{2}^{+}. Molecular ion yields are more sensitive to temperature than atomic ion yields. Based on the findings, we propose a desorption model in which positronic compounds are initially produced at the surface and subsequently desorbed as molecular ions via Auger decay following positron annihilation.

3.
Br Poult Sci ; 62(3): 414-423, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33314959

RESUMO

1. The purpose of the present study was to examine whether zymosan, which is a component of fungi, affects feed passage through the digestive tract in chicks (Gallus gallus).2. Intraperitoneal (IP) injection of 2.5 mg zymosan significantly reduced the crop-emptying rate and this effect was similar to that of 100 µg lipopolysaccharide (LPS). Zymosan affected phenol red transit from the proventriculus.3. Zymosan significantly affected the gene expression of interleukin-1ß (IL-1ß), IL-6, IL-8 and histidine decarboxylase in various regions of the digestive tract.4. The present study suggested that zymosan retarded feed passage through the digestive tract in chick and interleukins and histamine may be participating in this process.


Assuntos
Galinhas , Lipopolissacarídeos , Animais , Trato Gastrointestinal , Expressão Gênica , Zimosan
4.
Br Poult Sci ; 61(3): 303-310, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31973574

RESUMO

1. The purpose of the present study was to determine if an intraperitoneal injection of two toll-like receptor-7 (TLR7) agonists, imiquimod and resiquimod, affect feed intake, voluntary activity, cloacal temperature, crop-emptying rate, plasma corticosterone (CORT) and glucose concentrations, and splenic gene expression of cytokines in chicks (Gallus gallus). 2. Although intraperitoneal injection of 100 µg imiquimod significantly increased splenic gene expression of interleukin-1ß (IL-1ß), IL-6, IL-8, and interferon-γ (IFN-γ), it did not affect feed intake, voluntary activity, cloacal temperature, crop-emptying rate or plasma constituents. 3. Intraperitoneal injection of 100 µg resiquimod significantly decreased feed intake, voluntary activity, cloacal temperature, crop-emptying rate and increased plasma corticosterone concentrations. 4. Intraperitoneal injection of resiquimod significantly increased splenic gene expression of IL-1ß, IL-6, IL-8, IFN-γ, and tumour necrosis factor-like cytokine 1A. 5. The results showed that activation of TLR7 is associated with anorexia, hypoactivity, hypothermia, disturbance of feed passage in the digestive tract and the response to stress in chicks.


Assuntos
Galinhas , Comportamento Alimentar , Receptor 7 Toll-Like , Animais , Cloaca , Temperatura
5.
Ann Hematol ; 98(9): 2131-2138, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31286196

RESUMO

The optimal dose, schedule, and other aspects of bendamustine plus rituximab treatment remain unclear for patients with relapsed or refractory follicular lymphoma (FL). Herein, we analyzed the efficacy of bendamustine combined with rituximab (RB-120) treatment for Japanese patients with relapsed or refractory FL. This phase II clinical trial included patients with relapsed or refractory FL who received 375 mg/m2 rituximab on day 1 and 120 mg/m2 bendamustine on days 2 and 3 every 28 days for up to 6 cycles. The primary endpoint was the overall response rate (ORR), and the secondary endpoints included the complete response (CR) rate, progression-free survival (PFS), overall survival (OS), and safety. Thirty-seven patients were enrolled in the trial (median age 62 years, range 42-75 years). All patients were previously treated with rituximab-containing chemotherapy, and 83.8% were previously treated with the R-CHOP regimen. A median of 5 cycles (range 1-6) and 48.6% of patients completed 6 cycles. The ORR was 91.9% (95% confidence interval [CI] 78.1-98.3%), with a CR rate of 86.5% (95% CI 71.2-95.5%). The 3-year PFS and OS were 70.9% (95% CI 52.3-83.3%) and 88.9% (95% CI 73.1-95.7%), respectively, with the median 39.5 months follow-up duration. The most-frequently observed grade 3/4 adverse events were hematologic: lymphopenia (95%) and neutropenia (70%). No treatment-related deaths were observed. RB-120 showed a good efficacy with equivalent toxicities, compared with the bendamustine 120 mg/m2 monotherapy. However, the problem of high drop-out incidences cannot be ignored.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/administração & dosagem , Linfoma Folicular , Adulto , Idoso , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Cloridrato de Bendamustina/administração & dosagem , Cloridrato de Bendamustina/efeitos adversos , Intervalo Livre de Doença , Feminino , Seguimentos , Humanos , Linfoma Folicular/tratamento farmacológico , Linfoma Folicular/mortalidade , Masculino , Pessoa de Meia-Idade , Neutropenia/induzido quimicamente , Neutropenia/mortalidade , Rituximab/administração & dosagem , Rituximab/efeitos adversos , Taxa de Sobrevida
6.
Br Poult Sci ; 60(1): 64-70, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30421962

RESUMO

1. The purpose of the present study was to determine if intracerebroventricular (ICV) and intraperitoneal (IP) injection of polyinosinic-polycytidylic acid (poly I:C), a viral mimetic that binds to toll-like receptor-3 (TLR3), affects food intake, voluntary activity, cloacal temperature, plasma corticosterone (CORT) and glucose concentrations, and crop emptying rate in chicks (Gallus gallus). 2. Both ICV and IP injection of poly I:C significantly decreased food intake. 3. IP but not ICV injection of poly I:C significantly suppressed voluntary activity, whereas ICV injection decreased time spent sitting. Both ICV and IP injection of poly I:C significantly increased plasma CORT and glucose concentration. Neither ICV nor IP injection of poly I:C significantly affected cloacal temperature. 4. In addition, ICV injection of poly I:C significantly reduced crop emptying rate, whereas IP injection had no effect. 5. These results suggested that central TLR3 is related to anorexia, stress response and retardation of crop emptying while peripheral TLR3 is related to anorexia, change in behaviour and stress responses during viral infection in chicks.


Assuntos
Galinhas/fisiologia , Corticosterona/sangue , Comportamento Alimentar/efeitos dos fármacos , Glucose/metabolismo , Locomoção/efeitos dos fármacos , Poli I-C/administração & dosagem , Animais , Cloaca/efeitos dos fármacos , Cloaca/fisiologia , Papo das Aves/efeitos dos fármacos , Papo das Aves/fisiologia , Digestão/efeitos dos fármacos , Injeções Intraperitoneais/veterinária , Injeções Intraventriculares/veterinária , Masculino , Temperatura
7.
Phys Rev Lett ; 118(3): 033202, 2017 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-28157370

RESUMO

The hitherto unexplored two-photon doubly excited states [Ne^{*}(2p^{-1}3s)]_{2} were experimentally identified using the seeded, fully coherent, intense extreme ultraviolet free-electron laser FERMI. These states undergo ultrafast interatomic Coulombic decay (ICD), which predominantly produces singly ionized dimers. In order to obtain the rate of ICD, the resulting yield of Ne_{2}^{+} ions was recorded as a function of delay between the extreme ultraviolet pump and UV probe laser pulses. The extracted lifetimes of the long-lived doubly excited states, 390(-130/+450) fs, and of the short-lived ones, less than 150 fs, are in good agreement with ab initio quantum mechanical calculations.

8.
Br Poult Sci ; 58(1): 100-106, 2017 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-27871194

RESUMO

1. We examined the effect of lipopolysaccharide (LPS), a component of Gram-negative bacteria, on food passage in the digestive tract of chickens (Gallus gallus) in order to clarify whether bacterial infection affects food passage in birds. 2. Food passage in the crop was significantly reduced by intraperitoneal (IP) injection of LPS while it did not affect the number of defecations, suggesting that LPS may affect food passage only in the upper digestive tract. 3. Similar to LPS, prostaglandin E2 (PGE2), one of the mediators of LPS, also reduced crop-emptying rate in chickens while it had no effect on the number of defecations. 4. Pretreatment with indomethacin, which is an inhibitor of cyclooxygenase (COX), a prostaglandin synthase, had no effect on LPS-induced inhibition of crop emptying. 5. IP injection of LPS did not affect the mRNA expression of COX2 in the upper digestive tract of chickens. 6. It is therefore likely that LPS and PGE2 reduced food passage rate in the crop by a prostaglandin-independent pathway in chickens.


Assuntos
Galinhas/metabolismo , Papo das Aves/metabolismo , Digestão/efeitos dos fármacos , Lipopolissacarídeos/farmacologia , Prostaglandinas/fisiologia , Animais , Ciclo-Oxigenase 2/genética , Inibidores de Ciclo-Oxigenase/farmacologia , Dinoprostona/farmacologia , Alimentos , Expressão Gênica/efeitos dos fármacos , Indometacina/farmacologia , Peritônio/efeitos dos fármacos , RNA Mensageiro/análise
9.
Br Poult Sci ; 58(3): 305-311, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28090781

RESUMO

1. The purpose of the present study was to determine if central interleukin-1ß (IL1ß), interleukin-6 (IL6) and interleukin-8 (IL8) affect feeding behaviour in chicks (Gallus gallus) and examine if central interleukins are related to the lipopolysaccharide (LPS)-induced anorexia. 2. Intra-abdominal (IA) injection of LPS significantly suppressed feeding behaviour and significantly increased mRNA expression of IL1ß and IL8 in the diencephalon when compared to the control group, while IL6 tended to be increased. 3. Intracerebroventricular (ICV) injection of 200 ng IL1ß significantly decreased food intake at 60 min after the injection while IL6 and IL8 had no effect. 4. IA injection of these ILs (200 ng) had no effect on food intake in chicks. 5. ICV injection of 200 ng IL1ß did not affect water intake and plasma corticosterone concentration, suggesting that central IL1ß might not be related to the regulation of drinking behaviour and the hypothalamus-pituitary-adrenal axis. 6. The present study demonstrated that central IL1ß but not IL6 and IL8 might be related to the inhibition of feeding in chicks.


Assuntos
Galinhas/fisiologia , Comportamento Alimentar/efeitos dos fármacos , Expressão Gênica , Interleucina-1beta/metabolismo , Interleucina-6/metabolismo , Interleucina-8/metabolismo , Lipopolissacarídeos/farmacologia , Animais , Corticosterona/sangue , Diencéfalo/metabolismo , Comportamento de Ingestão de Líquido/efeitos dos fármacos , Infusões Intraventriculares , Masculino , Especificidade de Órgãos , RNA Mensageiro/metabolismo
10.
Phys Rev Lett ; 117(27): 276806, 2016 Dec 30.
Artigo em Inglês | MEDLINE | ID: mdl-28084773

RESUMO

Ne clusters (∼5000 atoms) were resonantly excited (2p→3s) by intense free electron laser (FEL) radiation at FERMI. Such multiply excited clusters can decay nonradiatively via energy exchange between at least two neighboring excited atoms. Benefiting from the precise tunability and narrow bandwidth of seeded FEL radiation, specific sites of the Ne clusters were probed. We found that the relaxation of cluster surface atoms proceeds via a sequence of interatomic or intermolecular Coulombic decay (ICD) processes while ICD of bulk atoms is additionally affected by the surrounding excited medium via inelastic electron scattering. For both cases, cluster excitations relax to atomic states prior to ICD, showing that this kind of ICD is rather slow (picosecond range). Controlling the average number of excitations per cluster via the FEL intensity allows a coarse tuning of the ICD rate.

11.
Faraday Discuss ; 194: 537-562, 2016 12 16.
Artigo em Inglês | MEDLINE | ID: mdl-27797386

RESUMO

We studied the electronic and nuclear dynamics of I-containing organic molecules induced by intense hard X-ray pulses at the XFEL facility SACLA in Japan. The interaction with the intense XFEL pulse causes absorption of multiple X-ray photons by the iodine atom, which results in the creation of many electronic vacancies (positive charges) via the sequential electronic relaxation in the iodine, followed by intramolecular charge redistribution. In a previous study we investigated the subsequent fragmentation by Coulomb explosion of the simplest I-substituted hydrocarbon, iodomethane (CH3I). We carried out three-dimensional momentum correlation measurements of the atomic ions created via Coulomb explosion of the molecule and found that a classical Coulomb explosion model including charge evolution (CCE-CE model), which accounts for the concerted dynamics of nuclear motion and charge creation/charge redistribution, reproduces well the observed momentum correlation maps of fragment ions emitted after XFEL irradiation. Then we extended the study to 5-iodouracil (C4H3IN2O2, 5-IU), which is a more complex molecule of biological relevance, and confirmed that, in both CH3I and 5-IU, the charge build-up takes about 10 fs, while the charge is redistributed among atoms within only a few fs. We also adopted a self-consistent charge density-functional based tight-binding (SCC-DFTB) method to treat the fragmentations of highly charged 5-IU ions created by XFEL pulses. Our SCC-DFTB modeling reproduces well the experimental and CCE-CE results. We have also investigated the influence of the nuclear dynamics on the charge redistribution (charge transfer) using nonadiabatic quantum-mechanical molecular dynamics (NAQMD) simulation. The time scale of the charge transfer from the iodine atomic site to the uracil ring induced by nuclear motion turned out to be only ∼5 fs, indicating that, besides the molecular Auger decay in which molecular orbitals delocalized over the iodine site and the uracil ring are involved, the nuclear dynamics also play a role for ultrafast charge redistribution. The present study illustrates that the CCE-CE model as well as the SCC-DFTB method can be used for reconstructing the positions of atoms in motion, in combination with the momentum correlation measurement of the atomic ions created via XFEL-induced Coulomb explosion of molecules.

12.
Phys Rev Lett ; 111(9): 093402, 2013 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-24033032

RESUMO

The lifetime of interatomic Coulombic decay (ICD) [L. S. Cederbaum et al., Phys. Rev. Lett. 79, 4778 (1997)] in Ne2 is determined via an extreme ultraviolet pump-probe experiment at the Free-Electron Laser in Hamburg. The pump pulse creates a 2s inner-shell vacancy in one of the two Ne atoms, whereupon the ionized dimer undergoes ICD resulting in a repulsive Ne+(2p(-1))-Ne+(2p(-1)) state, which is probed with a second pulse, removing a further electron. The yield of coincident Ne+-Ne2+ pairs is recorded as a function of the pump-probe delay, allowing us to deduce the ICD lifetime of the Ne2(+)(2s(-1)) state to be (150±50) fs, in agreement with quantum calculations.

13.
Phys Rev Lett ; 110(17): 173005, 2013 Apr 26.
Artigo em Inglês | MEDLINE | ID: mdl-23679721

RESUMO

We have investigated multiphoton multiple ionization dynamics of xenon atoms using a new x-ray free-electron laser facility, SPring-8 Angstrom Compact free electron LAser (SACLA) in Japan, and identified that Xe(n+) with n up to 26 is produced at a photon energy of 5.5 keV. The observed high charge states (n≥24) are produced via five-photon absorption, evidencing the occurrence of multiphoton absorption involving deep inner shells. A newly developed theoretical model, which shows good agreement with the experiment, elucidates the complex pathways of sequential electronic decay cascades accessible in heavy atoms. The present study of heavy-atom ionization dynamics in high-intensity hard-x-ray pulses makes a step forward towards molecular structure determination with x-ray free-electron lasers.

14.
J Eur Acad Dermatol Venereol ; 27(7): 867-75, 2013 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-22646803

RESUMO

BACKGROUND: Although dermokine-ß, a glycoprotein expressed in epithelial cells, does not have significant homology to other proteins, its carboxyl-terminal domain shares a high pI value with many cytokines, suggesting similar functions. OBJECTIVE: To better understand the biology of dermokine, we here determined its localization under pathological conditions and examined factors that regulate its expression. METHODS: We generated an anti-human dermokine-ß/γ monoclonal antibody cross-reacting with the mouse protein. Using this antibody, immunohistological staining and Western blotting of dermokine-ß/γ were performed with various tissue samples. RESULTS: Although human dermokine-ß/γ was expressed in almost all granular layers, upper spinous layers of the skin were also stained with anti-dermokine-ß/γ antibody in inflammatory skin disorders. Dermokine-ß/γ was expressed in keratoacanthoma and a part of well-differentiated squamous cell carcinoma (SCC). However, dermokine-ß/γ was not detected in poorly differentiated SCC or tumours derived from non-keratinocytes. In mice, dermokine-ß/γ-expressed keratinocytes were increased in models of contact hypersensitivity, ultraviolet-irradiated skin injury and wound healing. Consistent with expanded distribution in inflammatory skin diseases, proinflammatory cytokines such as interleukin-1ß, interleukin-12, and tumour necrosis factor-α augmented dermokine-ß/γ expression in cultured human keratinocytes. In contrast, growth factors including epidermal growth factor, insulin-like growth factor-I, keratinocyte growth factor and transforming growth factor-α significantly reduced dermokine expression. CONCLUSION: These results provide novel insights into the physiological and pathological significance of dermokine in the epidermis.


Assuntos
Proteínas , Dermatopatias/metabolismo , Animais , Células Cultivadas , Regulação da Expressão Gênica , Humanos , Peptídeos e Proteínas de Sinalização Intercelular , Camundongos , Camundongos Endogâmicos C57BL , Proteínas/análise , Proteínas/genética , Pele/química , Dermatopatias/genética
15.
Phys Rev Lett ; 106(15): 153401, 2011 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-21568556

RESUMO

Photodetachment of the positronium negative ion, a bound state of one positron and two electrons, has been observed. Development of a method to produce the ions efficiently using a Na coated tungsten surface has enabled the first observation of the photodetachment. The obtained lower limit of the photodetachment cross section for the wavelength of 1064 nm is consistent with the theoretical calculations reported so far. The experimental field developed in the present work gives new opportunities to explore the quantum mechanical three-body problem and to develop energy-tunable positronium beams.

16.
Phys Rev Lett ; 106(5): 052502, 2011 Feb 04.
Artigo em Inglês | MEDLINE | ID: mdl-21405387

RESUMO

The ß-decay half-lives of 38 neutron-rich isotopes from (36)Kr to (43)Tc have been measured; the half-lives of (100)Kr, (103-105)Sr, (106-108)Y, (108-110)Zr, (111,112)Nb, (112-115)Mo, and (116,117)Tc are reported here. The results when compared with previous standard models indicate an overestimation in the predicted half-lives by a factor of 2 or more in the A≈110 region. A revised model based on the second generation gross theory of ß decay better predicts the measured half-lives and suggests a more rapid flow of the rapid neutron-capture process (r-matter flow) through this region than previously predicted.

17.
Domest Anim Endocrinol ; 72: 106471, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32279040

RESUMO

Zymosan is a cell wall component of the yeast Saccharomyces cerevisiae and produces severe inflammatory responses in mammals. When zymosan is peripherally injected in mammals, it induces several behavioral and physiological changes including anorexia and hyperthermia. However, to our knowledge, behavioral and physiological responses to zymosan have not yet been clarified in birds. Therefore, the purpose of the present study was to determine if intraperitoneal injection of zymosan affects food intake, voluntary activity, cloacal temperature, plasma corticosterone (CORT) and glucose concentrations, and splenic gene expression of cytokines in chicks (Gallus gallus). Intraperitoneal injection of zymosan (2.5 mg) significantly decreased food intake, voluntary activity, and plasma glucose concentration, and increased plasma CORT concentration. The injection of 0.5 mg zymosan significantly increased cloacal temperature, while 2.5 mg zymosan had a tendency to increase it. Finally, 2.5 mg zymosan significantly increased the splenic gene expression of interleukin-1ß (IL-1ß), IL-6, IL-8, interferon-γ, and tumor necrosis factor-like cytokine 1A. The present results suggest that zymosan would be one of components which induces nonspecific symptoms including anorexia, hypoactivity, hyperthermia, and stress responses, under fungus infection in chicks.


Assuntos
Comportamento Animal/efeitos dos fármacos , Galinhas/fisiologia , Zimosan/farmacologia , Animais , Glicemia/efeitos dos fármacos , Corticosterona/sangue , Citocinas/genética , Citocinas/metabolismo , Relação Dose-Resposta a Droga , Regulação da Expressão Gênica/efeitos dos fármacos , Hipertermia/induzido quimicamente , Injeções Intraperitoneais , Masculino , Tamanho do Órgão , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Baço/anatomia & histologia , Baço/metabolismo , Estresse Fisiológico/efeitos dos fármacos , Zimosan/administração & dosagem
18.
Domest Anim Endocrinol ; 72: 106464, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32279041

RESUMO

Prolactin-releasing peptide (PrRP) increases food intake in birds, whereas it is a potent satiety factor in rodents and fish. The aim of this study was to determine the effects of central injection of PrRP on feeding behaviors and hypothalamic physiology in juvenile Japanese quail (Coturnix japonica). Intracerebroventricular injection of 1,692 pmol of PrRP increased food intake for the first 90 min after injection but did not affect water intake. Quail treated with PrRP displayed more food and drink pecks, less time standing but more perching, and decreased defecations. Prolactin-releasing peptide-injected quail had increased c-Fos immunoreactivity in the dorsomedial nucleus (DMN) and arcuate nucleus (ARC) of the hypothalamus. Hypothalamic neuropeptide Y receptor subtypes 2 and 5 and melanocortin receptor 4 mRNAs were greater in PrRP- than vehicle-injected quail. In the DMN, there was less corticotropin-releasing factor (CRF) mRNA and in the ARC, more CRF mRNA in PrRP- than vehicle-injected chicks. Thus, PrRP increases food intake in quail, which is associated with changes in hypothalamic CRF and neuropeptide Y receptor gene expression and c-Fos-immunolabeled cells in the ARC and DMN.


Assuntos
Coturnix , Comportamento Alimentar/efeitos dos fármacos , Hipotálamo/efeitos dos fármacos , Hormônio Liberador de Prolactina/farmacologia , Animais , Comportamento Animal , Hormônio Liberador da Corticotropina/genética , Hormônio Liberador da Corticotropina/metabolismo , Feminino , Regulação da Expressão Gênica/efeitos dos fármacos , Hipotálamo/fisiologia , Infusões Intraventriculares , Masculino , Proteínas Proto-Oncogênicas c-fos/genética , Proteínas Proto-Oncogênicas c-fos/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo
19.
J Cell Biol ; 139(4): 841-9, 1997 Nov 17.
Artigo em Inglês | MEDLINE | ID: mdl-9362503

RESUMO

A 97-kD component of nuclear pore-targeting complex (the beta-subunit of nuclear pore-targeting complex [PTAC]/importin/karyopherin) mediates the import of nuclear localization signal (NLS)-containing proteins by anchoring the NLS receptor protein (the alpha-subunit of PTAC/importin/karyopherin) to the nuclear pore complex (NPC). The import requires a small GTPase Ran, which interacts directly with the beta-subunit. The present study describes an examination of the behavior of the beta-subunit in living cells and in digitonin-permeabilized cells. In living cells, cytoplasmically injected beta-subunit rapidly migrates into the nucleus. The use of deletion mutants reveals that nuclear migration of the beta-subunit requires neither Ran- nor alpha-subunit-binding but only the NPC-binding domain of this molecule, which is also involved in NLS-mediated import. Furthermore, unlike NLS-mediated import, a dominant-negative Ran, defective in GTP-hydrolysis, did not inhibit nuclear migration of the beta-subunit. In the digitonin-permeabilized cell-free import assay, the beta-subunit transits rapidly through the NPC into the nucleus in a saturating manner in the absence of exogenous addition of soluble factors. These results show that the beta-subunit undergoes translocation at the NPC in a Ran-unassisted manner when it does not carry alpha-subunit/NLS substrate. Therefore, a requirement for Ran arises only when the beta-subunit undergoes a translocation reaction together with the alpha-subunit/NLS substrate. The results provide an insight to the yet unsolved question regarding the mechanism by which proteins are directionally transported through the NPC, and the role of Ran in this process.


Assuntos
Núcleo Celular/metabolismo , Membrana Nuclear/metabolismo , Proteínas Nucleares/metabolismo , Proteínas Nucleares/fisiologia , Animais , Transporte Biológico , Bovinos , Compartimento Celular , Linhagem Celular , Citoplasma/metabolismo , Guanosina Trifosfato/metabolismo , Humanos , Carioferinas , Peso Molecular , Proteínas Nucleares/química , Proteína ran de Ligação ao GTP
20.
J Cell Biol ; 144(4): 645-55, 1999 Feb 22.
Artigo em Inglês | MEDLINE | ID: mdl-10037787

RESUMO

A small GTPase Ran is a key regulator for active nuclear transport. In immunoblotting analysis, a monoclonal antibody against recombinant human Ran, designated ARAN1, was found to recognize an epitope in the COOH-terminal domain of Ran. In a solution binding assay, ARAN1 recognized Ran when complexed with importin beta, transportin, and CAS, but not the Ran-GTP or the Ran-GDP alone, indicating that the COOH-terminal domain of Ran is exposed via its interaction with importin beta-related proteins. In addition, ARAN1 suppressed the binding of RanBP1 to the Ran-importin beta complex. When injected into the nucleus of BHK cells, ARAN1 was rapidly exported to the cytoplasm, indicating that the Ran-importin beta-related protein complex is exported as a complex from the nucleus to the cytoplasm in living cells. Moreover, ARAN1, when injected into the cultured cells induces the accumulation of endogenous Ran in the cytoplasm and prevents the nuclear import of SV-40 T-antigen nuclear localization signal substrates. From these findings, we propose that the binding of RanBP1 to the Ran-importin beta complex is required for the dissociation of the complex in the cytoplasm and that the released Ran is recycled to the nucleus, which is essential for the nuclear protein transport.


Assuntos
Anticorpos Monoclonais , GTP Fosfo-Hidrolases/imunologia , Proteínas Nucleares/imunologia , Sequência de Aminoácidos , Animais , Sequência de Bases , Transporte Biológico Ativo , Linhagem Celular , Núcleo Celular/metabolismo , Cricetinae , Citoplasma/metabolismo , Primers do DNA/genética , Epitopos/química , Epitopos/genética , GTP Fosfo-Hidrolases/genética , GTP Fosfo-Hidrolases/metabolismo , Proteínas de Ligação ao GTP/metabolismo , Humanos , Carioferinas , Substâncias Macromoleculares , Camundongos , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Proteínas Recombinantes/química , Proteínas Recombinantes/imunologia , Proteínas Recombinantes/metabolismo , Proteína ran de Ligação ao GTP
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