Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 84
Filtrar
1.
Nihon Koshu Eisei Zasshi ; 48(4): 276-88, 2001 Apr.
Artigo em Japonês | MEDLINE | ID: mdl-11398315

RESUMO

PURPOSE: In discussion on application of "National Health Promotion Toward 21st Century in Japan" in Kanagawa prefecture, it was noted that the age-adjusted mortality rate of death from ischemic heart disease in this part of Japan was higher than that for the whole nation in 1996. To facilitate development of a strategy for primary prevention of coronary heart disease (CHD), the present study was conducted to predict 2-yr incidence of CHD and decrease with simulations assuming improvement in CHD risk factors. METHODS: Using CHD risk prediction algorithm; the Weibull accelerated failure regression model based on the Framingham Heart Study, a 2-yr incidence of CHD was predicted for 1652 residents (515 male, 1137 female) on the basis of results of a health check up in 1998. We then estimated the probable decrease in CHD recalculated assuming decrease in total cholesterol (TC), increase in HDL-cholesterol (HDL-C), decrease in systolic blood pressure (SBP), or quitting the smoking habit. RESULTS: 1. The 2-yr probability of developing CHD for men free of heart disease was 2.79 +/- 2.17%, and that for men who had heart disease was 10.25 +/- 2.17%. The 2-yr probability for women free of heart disease was 16.80 +/- 14.40%, and that for women who had heart disease was 3.66 +/- 1.09%. As the reported probability of developing CHD in the U.S.A. is remarkably higher than in Japan, the fact that the present model was based on American data explains why these predicted probabilities are higher than values reported from Japanese cohort studies. 2. For men free of heart disease, a strategy for high risk case such as a decrease in TC and an increase in HDL-C, or quitting the smoking habit, was more effective than a population-based strategy. For women free of heart disease, the population-based strategy was more effective. 3. Women more than 60-yrs old who had a high 2-yr probability of developing CHD were divided into three groups; high, middle, and low risk. The mean body weight, mean body mass index, mean diastolic blood pressure, and mean blood glucose in the high risk group were significantly higher than the values in the other groups. Decrease in systolic blood pressure was a more effective strategy for decrease in CHD incidence in the high risk group than in the other groups. CONCLUSIONS: CHD risk prediction of this type may be considered useful for setting target CHD risk factors and for focusing interventions to prevent CHD effectively.


Assuntos
Doença das Coronárias/prevenção & controle , Adulto , Idoso , Doença das Coronárias/epidemiologia , Doença das Coronárias/etiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Análise de Regressão , Medição de Risco , Fatores de Risco , Fumar
2.
Theriogenology ; 55(7): 1431-45, 2001 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-11354704

RESUMO

This study investigated effects of adding hypotaurine (HT), beta-merocaptoethanol (beta-ME), or both into a chemically defined maturation medium (TCM-199 containing 0.1% polyvinyl alcohol: PVA) on maturation, fertilization and development of individually (single) cultured bovine oocytes. Mean GSH concentration in the oocytes cultured in the medium supplemented with either beta-ME (1.11 +/- 0.05 nM) or HT plus beta-ME (0.97 +/- 0.03 nM) was significantly (P < 0.05) higher than that in the medium containing PVA alone (0.75 +/- 0.03 nM). Adding beta-ME showed a significantly (P < 0.05) higher rate of the second metaphase stage (93.6 +/- 3.3%) than in the medium containing PVA alone (single-control) (65.2 +/- 7.9%). Adding both HT and beta-ME showed significantly (P < 0.05) higher rates (92.6 +/- 2.7%) of normal fertilization than did adding HT alone (63.5 +/- 4.6%). Also, adding both HT and beta-ME significantly (P < 0.05) lowered the polyspermy rate than did adding HT alone. Adding either beta-ME or both HT and beta-ME showed no significant difference in cleavage. Blastocyst development did not improve significantly adding either HT, beta-ME or both, although beta-ME alone or HT plus beta-ME tended to result in a higher rate of blastocysts (6.4 and 6.8%, respectively) than resulted without additives (1.6%). Our results show that adding beta-ME to a chemically defined maturation medium increased the intracellular GSH level of bovine oocytes cultured individually, and can improve the maturation rate leading to the blastocyst stage throughout in vitro production.


Assuntos
Meios de Cultura , Fertilização in vitro , Mercaptoetanol/farmacologia , Oócitos/efeitos dos fármacos , Oócitos/fisiologia , Taurina/análogos & derivados , Taurina/farmacologia , Animais , Blastocisto/efeitos dos fármacos , Blastocisto/fisiologia , Bovinos , Células Cultivadas , Feminino , Glutationa/análise , Mercaptoetanol/administração & dosagem , Oócitos/química , Taurina/administração & dosagem
3.
Pathol Int ; 51(4): 283-7, 2001 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-11350611

RESUMO

Goblet cell carcinoids are rare neoplasms that predominantly occur in the appendix. In this report we present a case of goblet cell carcinoid of the appendix. A 58-year-old male patient complaining of pain in the right lower quadrant was diagnosed with acute appendicitis and underwent an appendectomy. Histological examination of the resected appendix revealed goblet cell carcinoid. Infiltration of tumor cells beyond the appendix was observed and the surgically resected margin was positive for tumor cells. Carcinoembryonic antigen (CEA) was diffusely detected by immunohistochemistry, and cytokeratin 20, neuron-specific enolase (NSE), chromogranin A and serotonin were focally observed in the tumor cells. The expression of beta-catenin and E-cadherin was investigated to compare with that of typical rectal carcinoids (n = 3) and colon adenocarcinomas (n = 3). In normal colonic and rectal mucosae, beta-catenin and E-cadherin stained positive on the plasma membrane. In the case reported here, beta-catenin showed a preserved expression on the plasma membrane of goblet cell carcinoid; a pattern similar to typical carcinoids rather than to adenocarcinomas. However, E-cadherin demonstrated a reduced expression on the plasma membrane of the tumor cells. This staining pattern was identical to those both of carcinoids and of adenocarcinomas. These findings suggest the possibility that, in some cases, the adherens junctions of goblet cell carcinoids are similar to those of typical carcinoids rather than to those of adenocarcinomas.


Assuntos
Apêndice , Caderinas/metabolismo , Tumor Carcinoide/metabolismo , Neoplasias do Ceco/metabolismo , Proteínas do Citoesqueleto/metabolismo , Transativadores , Apêndice/patologia , Tumor Carcinoide/patologia , Neoplasias do Ceco/patologia , Humanos , Imuno-Histoquímica , Masculino , Pessoa de Meia-Idade , beta Catenina
4.
Theriogenology ; 53(8): 1553-65, 2000 May.
Artigo em Inglês | MEDLINE | ID: mdl-10883843

RESUMO

Culture of single oocytes throughout in vitro maturation (IVM), fertilization (IVF) and culture (IVC) provides detailed information on maturity, fertilizability and developmental capacity of individual bovine oocytes and embryos. In the present study, effects of sperm concentration (Experiment 1), microdrop size (Experiment 2), and the addition of hypotaurine (HT) or glutathione (GSH; Experiment 3) during IVF were investigated. In Experiment 4, in vitro maturity and developmental capacity of bovine oocytes cultured for IVM in a medium supplemented with fetal calf serum (FCS), bovine serum albumin (BSA) or polyvinyl alcohol (PVA) during IVM were investigated. In Experiments 1 to 3, the percentages of normal (2 pronuclei with a spermtail) and polyspermic fertilization in singly cultured oocytes were similar to those of group IVF culture (5 oocytes/drop). The addition of GSH during single oocyte IVF significantly increased the proportion of normal fertilization and decreased the polyspermic fertilization compared with addition of HT or of the control. The rates of mature oocytes (62.4 and 67.7%) and blastocyst development (12.9 and 15.2%) for single oocyte IVM cultures (Experiment 4) were also similar compared with the group culture; PVA supplementation significantly increased the matured oocyte rate, but decreased blastocyst development significantly (7.1%) as compared with FCS (19.5%) or BSA (15.6%). These results indicate that a single oocyte culture system throughout in vitro production of bovine embryos provides similar maturity, fertilizability and developmental capacity to oocytes cultured in groups.


Assuntos
Bovinos/fisiologia , Fertilização in vitro/veterinária , Oócitos/fisiologia , Animais , Bovinos/embriologia , Técnicas de Cultura de Células/métodos , Técnicas de Cultura de Células/veterinária , Meios de Cultura , Feminino , Fertilização in vitro/métodos , Glutationa/farmacologia , Modelos Lineares , Masculino , Oócitos/efeitos dos fármacos , Álcool de Polivinil/farmacologia , Gravidez , Soroalbumina Bovina/farmacologia , Espermatozoides/fisiologia , Taurina/análogos & derivados , Taurina/farmacologia
5.
Int J Epidemiol ; 29(2): 344-54, 2000 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-10817135

RESUMO

BACKGROUND: The spread of human immunodeficiency virus (HIV) in Cambodia is mainly caused by sexual transmission and the high-risk group in this country are female commercial sex workers (CSW). There are two types of CSW, direct CSW (DCSW) and indirect CSW (IDCSW), who are different from each other in sexual activities. This study was conducted in order to describe the risk factors on HIV for each type of CSW, and to establish effective preventive strategies against the HIV epidemic among CSW. METHODS: The participants, 143 DCSW and 94 IDCSW, were interviewed using a questionnaire to determine their demographic characteristics and behaviour. Blood samples were taken for serological tests on HIV, Chlamydia trachomatis and syphilis. The association between their behavioural pattern and their serological results was analysed. RESULTS: The questionnaire study showed that IDCSW had a riskier behavioural pattern than DCSW. The HIV seroprevalence rates of the DCSW and the IDCSW were 52.4% and 22.3%, respectively. Univariate logistic analyses showed a significant association between HIV antibody (HIV-Ab) and current age, age at commencement of commercial sex work, duration of commercial sex work, and the seropositivity of Chlamydia trachomatis-IgG antibody (CT-IgG-Ab) among the DCSW. The analyses also showed a significant relationship between HIV-Ab and CT-IgG-Ab among the IDCSW. CONCLUSIONS: Improving condom use rate is very important in order to prevent an HIV epidemic among the two types of CSW. This study also suggests it is important to prevent sexually transmitted disease (STD) such as Chlamydia trachomatis infection. The STD control programme could be efficient for HIV prevention, especially among DCSW.


Assuntos
Anticorpos Anti-HIV/sangue , Infecções por HIV/epidemiologia , Soroprevalência de HIV/tendências , HIV/imunologia , Trabalho Sexual , Comportamento Sexual/estatística & dados numéricos , Adolescente , Adulto , Anticorpos Antibacterianos/sangue , Camboja/epidemiologia , Infecções por Chlamydia/epidemiologia , Infecções por Chlamydia/microbiologia , Infecções por Chlamydia/transmissão , Chlamydia trachomatis/imunologia , Transmissão de Doença Infecciosa/prevenção & controle , Feminino , Infecções por HIV/transmissão , Infecções por HIV/virologia , Humanos , Fatores de Risco , Inquéritos e Questionários
6.
Ryumachi ; 40(6): 910-6, 2000 Dec.
Artigo em Japonês | MEDLINE | ID: mdl-11210776

RESUMO

We report two cases of systemic lupus erythematosus (SLE) diagnosed when acute peritonitis was appeared. Case 1 was a 20 year-old woman suffering from stomachache and right lower abdominal pain. Case 2 was a 40 year-old woman with diarrhea, epigastralgia, pollakisuria. In both cases, their peritoneal fluids were exudative with positive autoantibodies. After high dose steroid therapy, abdominal symptoms and ascites improved promptly. However, due to the complication of lupus nephritis, additional therapy was necessary. To characterize the feature of lupus peritonitis (LP), we examined the clinical and laboratory findings of LP from the literature. In patients with acute LP, abdominal pain, vomiting, diarrhea were significantly more common compared with chronic LP patients (P < 0.05), and fever, arthritis, central nervous system involvement and cystitis were more common. In patients with chronic LP, pleural effusion and pericardial effusion were more common compared with acute LP patients. Gastrointestinal manifestations such as abdominal pain, vomiting and diarrhea were more common in patients with acute LP compared with patients with chronic LP. Most patients with chronic LP were asymptomatic, ascites and serositis being the only clinical findings. The response to steroid therapy was better in acute LP.


Assuntos
Lúpus Eritematoso Sistêmico/diagnóstico , Peritonite/etiologia , Doença Aguda , Adulto , Feminino , Humanos , Lúpus Eritematoso Sistêmico/complicações , Peritonite/diagnóstico
7.
J Biochem ; 124(1): 122-9, 1998 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-9644254

RESUMO

Protein translocation across the cytoplasmic membrane of Escherichia coli is accomplished by concerted actions of the translocation ATPase SecA and the membrane-embedded SecE/Y/G complex. SecA interacts with preproteins and undergoes ATP-driven cycles of membrane insertion-deinsertion. To address how SecA interacts functionally with other components in the translocation machinery, we characterized a SecA mutant lacking amino-terminal 8 amino acid residues (SecA N-8). Although the absence of the 8 residues did not grossly affect the interaction of SecA with a preprotein, ATP, or phospholipids, nor did it affect the intrinsic ATPase activity, it gave differential effects on the translocation of different preproteins. It also affected the translocation ATPase activity, the ability of membrane insertion, and the topology inversion of SecG coupled with the membrane insertion-deinsertion of SecA. Most noteworthy, SecA N-8 was pronouncedly defective in the translocation of proton motive force-dependent preproteins, in which SecG might have a role. We propose that the amino-terminal region of SecA is important for the functional interaction with SecG.


Assuntos
Adenosina Trifosfatases/metabolismo , Proteínas de Bactérias/metabolismo , Proteínas de Escherichia coli , Escherichia coli/metabolismo , Proteínas de Membrana/metabolismo , Proteínas de Membrana Transportadoras , Adenosina Trifosfatases/química , Trifosfato de Adenosina/metabolismo , Proteínas de Bactérias/química , Sequência de Bases , Transporte Biológico , Primers do DNA , Escherichia coli/enzimologia , Fosfolipídeos/metabolismo , Canais de Translocação SEC , Proteínas SecA , Deleção de Sequência
9.
Gene ; 207(2): 135-40, 1998 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-9511754

RESUMO

A cDNA encoding the human homolog of the tumor necrosis factor receptor-associated factor 5 (TRAF5) protein has been molecularly cloned from a cDNA library of Human Daudi B cell line. The sequence analysis revealed that the cDNA encoded a protein of 557 aa residues with a calculated molecular weight of 64,236. The encoded protein has typical structural characteristics shown in the TRAF family of proteins and binds to the cytoplasmic region of lymphotoxin-beta receptor more efficiently than to that of CD40 and CD30. The TRAF5 gene was mapped to the human chromosome 1q32.3-q41.1. Overexpression of human TRAF5 activates NF kappa B transcription factor in human 293T kidney cells. These results suggest that the human TRAF5 protein could be involved in the signal triggered by various members of the tumor necrosis factor receptor (TNFR) superfamily including CD40, CD30 and lymphotoxin-beta receptor.


Assuntos
Proteínas de Transporte/genética , Proteínas , Fator de Necrose Tumoral alfa , Sequência de Aminoácidos , Animais , Proteínas de Transporte/metabolismo , Mapeamento Cromossômico , Cromossomos Humanos Par 1 , Clonagem Molecular , DNA Complementar , Expressão Gênica , Humanos , Camundongos , Dados de Sequência Molecular , NF-kappa B/metabolismo , Receptores do Fator de Necrose Tumoral/metabolismo , Homologia de Sequência de Aminoácidos , Transdução de Sinais , Fator 5 Associado a Receptor de TNF , Células Tumorais Cultivadas
10.
Biol Pharm Bull ; 21(2): 167-9, 1998 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-9514613

RESUMO

Human inter-alpha-trypsin-inhibitor (ITI) is a serine proteinase inhibitor with a molecular weight of 220 kDa which consists of 3 different polypeptides. The constitutive components are 2 heavy chains (H1 and H2 chains) and 1 light chain (L chain), and its inhibitory activity is considered to be derived from this L chain. It has also been reported that this L chain is almost identical to the trypsin inhibitor (UTI) occurring in human urine. We examined the gene expression of the ITI constitutive peptides in human tissues using the reverse transcription (RT) -PCR technique. As a result, the genes of the H1 chain were found to be expressed in various tissues, particularly strongly in the liver. On the other hand, the genes of the H2 chain were found to be strongly expressed in the adrenal glands, brain, kidneys, and lungs, as well as the liver. Further, the PCR amplification product of the L chain was strongly detected not only in the liver but also in the pancreas, kidneys, lungs, stomach and testes. These results suggest the possibility that the major tissue which produces ITI is the liver, and the H chains and L chain (UTI) are produced as a component of ITI- related proteins in other tissues as well as in the liver.


Assuntos
alfa-Globulinas/genética , Regulação da Expressão Gênica , DNA Complementar , Humanos , Reação em Cadeia da Polimerase , Sensibilidade e Especificidade
11.
J Biol Chem ; 272(32): 20082-7, 1997 Aug 08.
Artigo em Inglês | MEDLINE | ID: mdl-9242681

RESUMO

In this study, using a derivative of proOmpA containing an artificial stop-transfer sequence (proOmpA2xH1), we analyzed the process of stop-transfer during translocation across the cytoplasmic membrane of Escherichia coli. ProOmpA2xH1 did not interfere with the transit of wild-type proOmpA. When proOmpA2xH1 was anchored in the membrane, membrane-inserted SecA was deinserted with the reversion of the inverted topology of SecG. Cross-linking experiments revealed that the anchored proOmpA2xH1 that does not interact with either SecY or SecA. These results, taken together, suggest that proOmpA2xH1 leaves the translocation pathway by means of a specific interaction between the stop-transfer sequence and the translocational channel.


Assuntos
Proteínas da Membrana Bacteriana Externa/metabolismo , Proteínas de Escherichia coli , Escherichia coli/metabolismo , Precursores de Proteínas/metabolismo , Trifosfato de Adenosina/metabolismo , Proteínas da Membrana Bacteriana Externa/química , Proteínas de Bactérias/metabolismo , Sítios de Ligação , Transporte Biológico , Citoplasma/metabolismo , Hidrólise , Membranas Intracelulares/metabolismo , Proteínas de Membrana/metabolismo , Conformação Proteica , Precursores de Proteínas/química , Canais de Translocação SEC
12.
Biochim Biophys Acta ; 1326(1): 23-36, 1997 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-9188797

RESUMO

The positive charges of signal peptides are important for the interaction with SecA, a translocation ATPase. To examine whether or not the hydrophobic region of signal peptides also interacts with SecA, we constructed model preproteins, proOmpF-Lpps, possessing no positively charged amino acid residues at the amino-terminus and different numbers of alanine/leucine residues in the hydrophobic region of signal peptides. When the hydrophobic stretch was sufficiently long, amino-terminal positively charged residues were not required for the translocation of preproteins across the cytoplasmic membrane of Escherichia coli both in vitro and in vivo. Chemical cross-linking between SecA and preproteins possessing no positively charged residues at the amino-terminus was observed only in the presence of liposomes containing acidic phospholipids. The degree of cross-linking increased as the length of the hydrophobic stretch increased irrespective of whether positively charged residues were present or not. A preprotein possessing no positively charged residues at the amino-terminus, which is competent in the presence of liposomes, competitively inhibited the cross-linking of wild-type proOmpF-Lpp with SecA under the same conditions. It is concluded that both the amino-terminal positive charges and central hydrophobic domains are involved in the interaction with SecA in the initial stage of translocation in addition to their possible roles in transmembrane movement of preproteins.


Assuntos
Adenosina Trifosfatases/metabolismo , Proteínas de Bactérias/metabolismo , Membrana Celular/metabolismo , Proteínas de Escherichia coli , Proteínas de Membrana Transportadoras , Sinais Direcionadores de Proteínas/metabolismo , Proteínas Recombinantes , Adenosina Trifosfatases/farmacologia , Aminoácidos/análise , Proteínas da Membrana Bacteriana Externa/química , Proteínas da Membrana Bacteriana Externa/metabolismo , Proteínas de Bactérias/farmacologia , Transporte Biológico , Escherichia coli , Lipoproteínas/química , Lipoproteínas/metabolismo , Lipossomos , Estrutura Molecular , Fosfolipídeos/metabolismo , Plasmídeos , Precursores de Proteínas/química , Precursores de Proteínas/metabolismo , Sinais Direcionadores de Proteínas/química , Canais de Translocação SEC , Proteínas SecA
13.
J Biol Chem ; 272(9): 5880-6, 1997 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-9038205

RESUMO

Based on the finding that a series of engineered proOmpAs containing disulfide-bridged loops of different sizes at different positions exhibits a discontinuous mode of polypeptide transit across the cytoplasmic membrane of Escherichia coli, we suggested previously that the translocation of preproteins takes place at every 30 amino acid residues (Uchida, K., Mori, H., and Mizushima, S. (1995) J. Biol. Chem. 270, 30862-30868). In the present study, we investigated the molecular mechanism underlying this stepwise translocation. Deletion or relocation of hydrophobic segments of the mature domain of proOmpA (H1, residues 233-237; H2, residues 261-265) significantly altered the pattern of the stepwise translocation. The stepwise mode of polypeptide insertion was also observed with reconstituted proteoliposomes comprising purified SecA, SecY, and SecE. Cross-linking experiments involving a photoactivable cross-linker revealed that SecY and SecA are the components which interact with the hydrophobic segment of proOmpA. The present results indicate that the hydrophobic segments of the mature domains of preproteins interact with membrane embedded translocase during polypeptide transit across the membrane, which causes a discontinuous mode of polypeptide movement.


Assuntos
Proteínas da Membrana Bacteriana Externa/química , Membrana Celular/metabolismo , Proteínas de Escherichia coli , Proteínas de Membrana Transportadoras , Precursores de Proteínas/química , Adenosina Trifosfatases/metabolismo , Proteínas de Bactérias/metabolismo , Transporte Biológico , Endopeptidase K/metabolismo , Escherichia coli , Conformação Proteica , Canais de Translocação SEC , Proteínas SecA
14.
Rinsho Ketsueki ; 38(2): 146-8, 1997 Feb.
Artigo em Japonês | MEDLINE | ID: mdl-9059070

RESUMO

Serum levels of soluble interleukin-2 receptor (SIL-2R) and C-reactive protein (CRP) were measured in 12 patients with interstitial pneumonia (IP) and 10 patients with bacterial pneumonia (BP) of hematological malignancies. Mean SIL-2R levels (U/ml) were 394 +/- 140 in normal controls, 755 +/- 320 in BP, and 2328 +/- 943 in IP. A significantly higher level was found in IP than BP (p < 0.05). Moreover, the SIL-2R/CRP ratio which was over 260 in all cases of IP completely distinguished IP from BP. Levels of SIL-2R rose before the onset of IP and were closely associated with clinical course in most cases. From these results, measurement of serum SIL-2R may be useful for the diagnosis and monitoring of the clinical course of IP complicated with hematological diseases.


Assuntos
Neoplasias Hematológicas/complicações , Doenças Pulmonares Intersticiais/diagnóstico , Receptores de Interleucina-2/sangue , Proteína C-Reativa/análise , Humanos , Masculino , Pessoa de Meia-Idade , Pneumonia Bacteriana/diagnóstico
15.
J Biochem ; 121(2): 270-7, 1997 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-9089400

RESUMO

Newly recognized mammalian secretory proteins such as preprolactin are translocated across the endoplasmic reticulum (ER) in a signal recognition particle (SRP)-dependent manner. Recent studies revealed that there are two recognition steps for signal peptides during this translocation. The first step is recognition by SRP, which results in elongation arrest, and the second step is interaction between signal peptides and the translocation channel embedded in the ER membrane. To determine the roles of the hydrophobic region of signal peptides in the recognition by SRP and the membrane-embedded translocation machinery, we constructed chimeric proteins consisting of the mature region of preprolactin and signal peptides containing different numbers of leucine residues. The translocation of these chimeric proteins was completely dependent on SRP, and the efficiency increased as the number of leucine residues increased up to 10 and then decreased. Although the efficiency of elongation arrest also increased as the number of leucine residues increased up to 10, it only slightly decreased as the number increased up to 20. Similar results were obtained when the hydrophobic region was replaced by alternate leucine and alanine residues, except that the most efficient translocation occurred when the number was 14. Taken together, the present results suggests that the total hydrophobicity of the hydrophobic region of signal peptides is a determinant for recognition by both SRP and the membrane-embedded translocation machinery, although the specificities of the two signal recognition steps are slightly different from each other.


Assuntos
Retículo Endoplasmático/metabolismo , Membranas Intracelulares/metabolismo , Sinais Direcionadores de Proteínas/química , Partícula de Reconhecimento de Sinal/metabolismo , Sequência de Aminoácidos , Proteínas da Membrana Bacteriana Externa/genética , Proteínas da Membrana Bacteriana Externa/metabolismo , Sítios de Ligação , Transporte Biológico , Escherichia coli , Concentração de Íons de Hidrogênio , Dados de Sequência Molecular , Peptídeos/metabolismo , Prolactina/genética , Prolactina/metabolismo , Precursores de Proteínas/genética , Precursores de Proteínas/metabolismo , Sinais Direcionadores de Proteínas/metabolismo , Proteínas Recombinantes de Fusão/metabolismo
16.
J Biol Chem ; 271(46): 28745-8, 1996 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-8910514

RESUMO

CD40 signalings play crucial roles in B-cell function. To identify molecules which transduce CD40 signalings, we have utilized the yeast two-hybrid system to clone cDNAs encoding proteins that bind the cytoplasmic tail of CD40. A cDNA encoding a putative signal transducer, designated TRAF6, has been molecularly cloned. TRAF6 has a tumor necrosis factor receptor (TNFR)-associated factor (TRAF) domain in its carboxyl terminus and has a RING finger domain, a cluster of zinc fingers and a coiled-coil domain, which are also present in other TRAF family proteins. TRAF6 does not associate with the cytoplasmic tails of TNFR2, CD30, lymphotoxin-beta receptor, and LMP1 of Epstein-Barr virus. Deletion analysis showed that residues 246-269 of CD40 which are required for its association with TRAF2, TRAF3, and TRAF5 are dispensable for its interaction with TRAF6, whereas residues 230-245 were required. Overexpression of TRAF6 activates transcription factor NFkappaB, and its TRAF-C domain suppresses NFkappaB activation triggered by CD40 lacking residues 246-277. These results suggest that TRAF6 could mediate the CD40 signal that is transduced by the amino-terminal domain (230-245) of the CD40 cytoplasmic region and appears to be independent of other known TRAF family proteins.


Assuntos
Antígenos CD40/metabolismo , Proteínas de Transporte/metabolismo , Proteínas , Transdução de Sinais , Sequência de Aminoácidos , Animais , Proteínas de Transporte/química , DNA Complementar , Humanos , Células Jurkat , Camundongos , Camundongos Endogâmicos C57BL , Dados de Sequência Molecular , NF-kappa B/metabolismo , Ligação Proteica , Fator 6 Associado a Receptor de TNF , Células Tumorais Cultivadas
17.
J Biol Chem ; 271(29): 17439-44, 1996 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-8663354

RESUMO

The high affinity ATP-binding site of SecA is located in its amino-terminal domain possessing amino acid sequences, the Walker A (GXXXXGKT) and B (ZZZZD) motifs, that are characteristic of a major class of nucleotide-binding sites (Walker, J. E., Saraste, M., Runswick, M. J., and Gay, N. J. (1982) EMBO J. 1, 945-951). Recently, we proposed that proteins possessing a typical set of Walker A and B motifs contain a conserved Glu or Asp between the two motifs. This Glu or Asp acts as a "catalytic residue" that activates a water molecule for an in-line attack on the gamma-phosphate of ATP (Amano, T., Yoshida, M., Matsuo, Y., and Nishikawa, K.(1995) FEBS Lett. 359, 1-5). In the present study, the aspartate residue at position 133 in Escherichia coli SecA, which could be the "catalytic residue," was mutated to an asparagine. The mutant SecA (SecA D133N) protein was expressed in E. coli CK4706, encoding a duplication of the secA gene, and purified to homogeneity. The in vitro protein translocation activity and membrane vesicle stimulated ATPase activity of SecA D133N were drastically reduced. Proteolytic studies indicated that the conformational changes of the mutant SecA occurring on interaction with ATP, presecretory proteins, phospholipids, and membrane vesicles, were similar to those of wild-type SecA. The mutant SecA allowed the signal peptide cleavage of proOmpA during translocation, indicating that the mutant retains the ability to bind ATP to perform the initial step of the translocation reaction. These data indicate that the carboxyl group of Asp-133 plays a role as a catalytic carboxylate, which activates a water molecule to attack gamma-phosphate of ATP, and the mutant lacking this residue cannot perform the total translocation but can still perform the initial step of the protein translocation.


Assuntos
Adenosina Trifosfatases/química , Adenosina Trifosfatases/metabolismo , Trifosfato de Adenosina/metabolismo , Ácido Aspártico , Proteínas de Bactérias/química , Proteínas de Bactérias/metabolismo , Proteínas de Escherichia coli , Escherichia coli/enzimologia , Proteínas de Membrana Transportadoras , Sequência de Aminoácidos , Bactérias/enzimologia , Sequência de Bases , Sítios de Ligação , Transporte Biológico , Primers do DNA , Cinética , Dados de Sequência Molecular , Mutagênese Sítio-Dirigida , Plantas/enzimologia , Mutação Puntual , Proteínas Recombinantes/química , Proteínas Recombinantes/metabolismo , Canais de Translocação SEC , Proteínas SecA , Homologia de Sequência de Aminoácidos
18.
J Biochem ; 119(5): 863-9, 1996 May.
Artigo em Inglês | MEDLINE | ID: mdl-8797085

RESUMO

Nordihydroguaiaretic acid (NDGA) blocks intra-Golgi protein transport in a cell-free system and prolactin secretion from GH3 cells [Tagaya, M., Henomatsu, N., Yoshimori, T., Yamamoto, A., Tashiro, Y., and Fukui, T. (1993) FEBS Lett. 324, 201-204]. To determine which intracellular secretory pathway(s) is inhibited by NDGA, we investigated its effect on the transport of the vesicular stomatitis virus-encoded glycoprotein in BHK-21 cells. NDGA blocked protein transport from the endoplasmic reticulum to the Golgi apparatus, and from the trans-Golgi network to the plasma membrane. In addition, it retarded the brefeldin A-induced retrograde transport of mannosidase II to the endoplasmic reticulum. Although NDGA had an inhibitory effect on protein synthesis, it induced the expression of BiP, a chaperone located in the endoplasmic reticulum. The induction of BiP may be a consequence of the inhibition of protein transport by NDGA.


Assuntos
Membrana Celular/metabolismo , Retículo Endoplasmático/metabolismo , Complexo de Golgi/metabolismo , Proteínas de Choque Térmico , Manosidases/metabolismo , Masoprocol/farmacologia , Glicoproteínas de Membrana , Proteínas do Envelope Viral/metabolismo , Animais , Transporte Biológico/efeitos dos fármacos , Brefeldina A , Proteínas de Transporte/biossíntese , Linhagem Celular , Membrana Celular/efeitos dos fármacos , Cricetinae , Ciclopentanos/farmacologia , Retículo Endoplasmático/efeitos dos fármacos , Retículo Endoplasmático/ultraestrutura , Chaperona BiP do Retículo Endoplasmático , Glicoproteínas/metabolismo , Complexo de Golgi/efeitos dos fármacos , Complexo de Golgi/ultraestrutura , Microtúbulos/efeitos dos fármacos , Microtúbulos/metabolismo , Microtúbulos/ultraestrutura , Chaperonas Moleculares/biossíntese , Vírus da Estomatite Vesicular Indiana/fisiologia
19.
J Biol Chem ; 271(1): 466-70, 1996 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-8550603

RESUMO

The N-ethylmaleimide-sensitive factor (NSF), which is involved in the multisteps of protein transport, is released from Golgi membranes on in vitro incubation with Mg(2+)-ATP. However, several lines of evidence suggest that NSF is associated with membranes in spite of the presence of Mg2+ and ATP in vivo. We have used digitonin-permeabilized PC12 cells to investigate the mechanism underlying the association of NSF with membranes. In PC12 cells, immunoreactivity for NSF was observed in the nuclear membranes, the Golgi apparatus, and neuronal growth cones, where synaptic vesicles are concentrated. NSF associated with the Golgi apparatus was released on incubation with Mg(2+)-ATP, whereas NSF in the nuclear membranes and neuronal growth cones was not released on the same treatment. The addition of cytosol blocked the Mg(2+)-ATP-induced release of NSF from the Golgi apparatus. Chromatographic analyses revealed that the factor(s) that prevents NSF release from the Golgi apparatus was eluted at the same position as the soluble NSF attachment proteins (SNAPs). Purified His6-tagged alpha-SNAP exhibited such activity. His6-tagged alpha-SNAP also prevented the Mg(2+)-ATP-induced release of NSF from isolated Golgi membranes.


Assuntos
Trifosfato de Adenosina/farmacologia , Fatores Biológicos/metabolismo , Proteínas de Transporte/farmacologia , Digitonina/farmacologia , Etilmaleimida/farmacologia , Complexo de Golgi/metabolismo , Proteínas de Membrana/farmacologia , Proteínas de Transporte Vesicular , Animais , Células CHO , Permeabilidade da Membrana Celular , Cricetinae , Membranas Intracelulares/metabolismo , Células PC12 , Ligação Proteica , Ratos , Proteínas de Ligação a Fator Solúvel Sensível a N-Etilmaleimida
20.
Adv Exp Med Biol ; 403: 615-22, 1996.
Artigo em Inglês | MEDLINE | ID: mdl-8915402

RESUMO

OBJECTIVES: To assess effects of oral taurine supplementation on lipids and sympathetic nerve tone in healthy young men on experimental high fat and cholesterol diets. METHODS: Twenty-two healthy male volunteers, aged 18-29 years, were recruited for this randomized control trial after informed consent according to the Ethical Committee of Shimane Medical University. Volunteers were randomly allocated into 2 study groups and given experimental diet of identical regimen [total calorie 2500 kcal, cholesterol 1000 mg, polyunsaturated fat/saturated fat (P/S) ratio 0.52, fat 40% of total energy intake (%E), protein 14%E, carbohydrate 46%E] to raise serum cholesterol (CHO) level for 3 weeks. Alcohol intake, smoking and strenuous physical activities were prohibited. Taurine powder (6 g/day) was supplied to one group (T-group, N = 11) and placebo capsules to the other (C-group, N = 11), by a single-blind approach. Blood samples and 24 h urine specimens were obtained once every week. Two men in the C-group dropped out due to upper respiratory infection. There were no difference in age, body mass index (BMI) or blood pressure (BP) between the groups. Statistical analysis was performed by analysis of variance (ANOVA, repeated measurement) and Student's t-test. RESULTS: There were no changes in BMI and BP in either group during the period. Significant increases in total CHO (25.4 +/- 17.5 mg/dl, mean +/- SD), LDL-CHO (17.1 +/- 14.5) and LDL (43.9 +/- 37.6) were observed in C-group but were attenuated in the T-group. The T-group showed significant increases in VLDL-CHO, VLDL and TG. The T-group had significantly lower urinary norepinephrine excretion than the C-group in the last week. CONCLUSION: Oral taurine supplementation attenuated increases in T-CHO, LDL-CHO and LDL in healthy men on high fat cholesterol diets but induced significant increases in VLDL-CHO, VLDL and TG, which could be explained by a possible effect of taurine on lipoprotein lipase. Significantly lower urinary norepinephrine excretion observed by the taurine administration implies the suppression of the sympathetic nervous system.


Assuntos
Pressão Sanguínea/efeitos dos fármacos , Colesterol na Dieta , Lipídeos/sangue , Lipoproteínas/sangue , Sistema Nervoso Simpático/fisiologia , Taurina/farmacologia , Adolescente , Adulto , Análise de Variância , Colesterol/sangue , HDL-Colesterol/sangue , LDL-Colesterol/sangue , VLDL-Colesterol/sangue , Alimentos Fortificados , Humanos , Lipoproteínas LDL/sangue , Lipoproteínas VLDL/sangue , Masculino , Valores de Referência , Sistema Nervoso Simpático/efeitos dos fármacos , Taurina/administração & dosagem , Triglicerídeos/sangue
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA