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1.
J Gastroenterol ; 59(3): 209-215, 2024 03.
Artigo em Inglês | MEDLINE | ID: mdl-38245879

RESUMO

BACKGROUND: Endoscopic improvement (EI; a Mayo endoscopic subscore of 0 or 1) is considered a therapeutic target in ulcerative colitis (UC) treatment. The potential to estimate EI non-invasively is an advantage of intestinal ultrasound (IUS). In a previous study, we developed a new sonographic parameter, the submucosa index (SMI), calculated as the ratio of the submucosal thickness to bowel wall thickness (BWT), and reported that combining BWT and SMI results in a practical and promising criterion for estimating EI without color Doppler assessment. This study aimed to validate the EI estimation ability of our B mode-based criterion, the 'Kyorin Ultrasound Criterion for UC' (KUC-UC; BWT < 3.8 mm and SMI < 50%), using an external cohort. METHODS: Patients with UC who underwent IUS and colonoscopy within 15 days without a treatment change between examinations were included. IUS findings, including BWT, SMI, and modified Limberg score for vascularity of the colon, were assessed. RESULTS: Forty-four test pairs of IUS and colonoscopy examinations in a total of 122 colonic segments were analyzed. The KUC-UC showed positive predictive value (PPV) of 94.6% and negative predictive value (NPV) of 80.0% for EI. In comparison, PPV and NPV were 85.4% and 79.0%, respectively, for the common criterion BWT of < 3 mm, and 83.0% and 82.7% for the validated Milan Ultrasound Criteria (a score of ≤ 6.2). CONCLUSIONS: External validation showed that the KUC-UC using only B mode findings without complicated calculations is a feasible and accurate sonographic criterion for estimating the EI of UC.


Assuntos
Colite Ulcerativa , Dietilestilbestrol/análogos & derivados , Humanos , Colite Ulcerativa/diagnóstico por imagem , Colite Ulcerativa/tratamento farmacológico , Colonoscopia/métodos , Ultrassonografia/métodos , Intestinos , Índice de Gravidade de Doença
2.
Clin J Gastroenterol ; 16(6): 815-821, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37695416

RESUMO

We present a case of life-threatening gastrointestinal bleeding caused by a penetrating atherosclerotic ulcer (PAU) that ruptured into the esophagus. A 65-year-old man presented with pyrexia and nausea. Contrast-enhanced computed tomography (CT) performed on admission revealed a hematoma between the lower esophagus and descending aorta due to a contained rupture of a PAU, which was undiagnosed at that time. Esophagogastroduodenoscopy (EGD) performed on the fifth day of admission revealed a subepithelial lesion in the lower esophagus, further complicated by ulcer formation. Biopsy did not reveal any malignant findings. On the eighth day of admission, the patient experienced substantial hematemesis with vital signs indicative of shock. Emergency EGD was performed, which revealed life-threatening bleeding in the lower esophagus. Contrast-enhanced CT revealed an aortoesophageal fistula with massive hematemesis, after which the patient died. An autopsy revealed perforation of the PAU into the esophagus without aortic dissection or a true aneurysm.Patients with atherosclerosis who develop recent-onset gastrointestinal symptoms, progressive anemia, and/or periaortic lesions should be carefully evaluated using contrast-enhanced CT, and PAU should be considered in the differential diagnosis.


Assuntos
Doenças da Aorta , Úlcera Aterosclerótica Penetrante , Masculino , Humanos , Idoso , Hematemese/etiologia , Doenças da Aorta/complicações , Doenças da Aorta/diagnóstico por imagem , Esôfago/patologia , Hemorragia Gastrointestinal/etiologia , Hemorragia Gastrointestinal/complicações , Úlcera/complicações , Úlcera/diagnóstico por imagem
3.
J Nat Prod ; 84(2): 453-458, 2021 02 26.
Artigo em Inglês | MEDLINE | ID: mdl-33480692

RESUMO

During the course of our investigations of fairy chemicals (FCs), we found S-ICAr-H (8a), as a metabolite of imidazole-4-carboxamide (ICA) in rice and yeast (Saccharomyces cerevisiae). In order to determine its absolute configuration, an efficient synthetic method of 8a was developed. This synthetic strategy was applicable to the preparation of analogues of 8a that might be biologically very important, such as S-ICAr-M (9), S-AICAr-H (10), and S-AICAr-M (11).


Assuntos
Aminoimidazol Carboxamida/análogos & derivados , Oryza/metabolismo , S-Adenosil-Homocisteína/análogos & derivados , Saccharomyces cerevisiae/metabolismo , Aminoimidazol Carboxamida/química , Aminoimidazol Carboxamida/metabolismo , Estrutura Molecular
4.
Front Nutr ; 7: 85, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32714940

RESUMO

We report a case involving a 92-year-old man who successfully received treatment with ninjin'yoeito, a Japanese herbal medicine, during the rehabilitation phase after hip fracture surgery. The patient was diagnosed with a left femoral neck fracture and underwent surgery. Two weeks after surgery, he was admitted to a rehabilitation hospital. At that time, his height, weight, body fat percentage, muscle mass, and Functional Independence Measure (FIM) score were 167 cm, 61 kg, 34.1%, 38.2 kg, and 49, respectively. For 1 month after surgery (i.e., 2 weeks after admission to the rehabilitation facility), he received rikkunshito, a traditional Japanese herbal medicine also known as Kampo medicine, for appetite loss and underwent rehabilitation. However, his appetite loss showed no improvement, and rikkunshito (7.5 g/d) was replaced with ninjin'yoeito (7.5 g/d). Two months later, although the patient's body weight and body fat percentage decreased to 56.5 kg and 21.1%, respectively, his muscle mass increased to 38.9 kg. Nutritional status evaluation indicated an improvement in the level of proteins such as transferrin, prealbumin, and retinol-binding protein, which reflected an increase in food intake. The FIM score improved from 49 to 105. No side effects were observed. The findings from this case suggest that ninjin'yoeito, which includes Astragalus root and Schisandra fruit, may be an effective treatment option for sarcopenia or frailty with appetite loss and impaired activities of daily living in aged patients.

5.
FEBS Lett ; 589(5): 576-80, 2015 Feb 27.
Artigo em Inglês | MEDLINE | ID: mdl-25625920

RESUMO

We identified a yeast mutant with temperature-sensitive growth defects that were rescued by VCP expression. The mutation occurred in GPI10, which encodes a mannosyl transferase for glycosylphosphatidylinositol anchor formation in the endoplasmic reticulum, and caused a Gly469Glu substitution in Gpi10. The mutant exhibited increased unfolded protein response, which was partially rescued by VCP or Cdc48, and showed sensitivity against cell-wall stressors, which were not rescued by VCP. These results suggest a potential link between VCP/Cdc48 and Gpi10 functions in the control of cell growth.


Assuntos
Adenosina Trifosfatases/metabolismo , Proteínas de Ciclo Celular/metabolismo , Manosiltransferases/metabolismo , Proteínas de Membrana/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/crescimento & desenvolvimento , Saccharomyces cerevisiae/metabolismo , Adenosina Trifosfatases/genética , Proteínas de Ciclo Celular/genética , Retículo Endoplasmático/metabolismo , Manosiltransferases/genética , Proteínas de Membrana/genética , Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/genética , Temperatura , Proteína com Valosina
6.
Nature ; 510(7503): 162-6, 2014 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-24784582

RESUMO

PINK1 (PTEN induced putative kinase 1) and PARKIN (also known as PARK2) have been identified as the causal genes responsible for hereditary recessive early-onset Parkinsonism. PINK1 is a Ser/Thr kinase that specifically accumulates on depolarized mitochondria, whereas parkin is an E3 ubiquitin ligase that catalyses ubiquitin transfer to mitochondrial substrates. PINK1 acts as an upstream factor for parkin and is essential both for the activation of latent E3 parkin activity and for recruiting parkin onto depolarized mitochondria. Recently, mechanistic insights into mitochondrial quality control mediated by PINK1 and parkin have been revealed, and PINK1-dependent phosphorylation of parkin has been reported. However, the requirement of PINK1 for parkin activation was not bypassed by phosphomimetic parkin mutation, and how PINK1 accelerates the E3 activity of parkin on damaged mitochondria is still obscure. Here we report that ubiquitin is the genuine substrate of PINK1. PINK1 phosphorylated ubiquitin at Ser 65 both in vitro and in cells, and a Ser 65 phosphopeptide derived from endogenous ubiquitin was only detected in cells in the presence of PINK1 and following a decrease in mitochondrial membrane potential. Unexpectedly, phosphomimetic ubiquitin bypassed PINK1-dependent activation of a phosphomimetic parkin mutant in cells. Furthermore, phosphomimetic ubiquitin accelerates discharge of the thioester conjugate formed by UBCH7 (also known as UBE2L3) and ubiquitin (UBCH7∼ubiquitin) in the presence of parkin in vitro, indicating that it acts allosterically. The phosphorylation-dependent interaction between ubiquitin and parkin suggests that phosphorylated ubiquitin unlocks autoinhibition of the catalytic cysteine. Our results show that PINK1-dependent phosphorylation of both parkin and ubiquitin is sufficient for full activation of parkin E3 activity. These findings demonstrate that phosphorylated ubiquitin is a parkin activator.


Assuntos
Proteínas Quinases/metabolismo , Ubiquitina-Proteína Ligases/metabolismo , Ubiquitina/metabolismo , Animais , Ativação Enzimática , Fibroblastos , Células HeLa , Humanos , Potencial da Membrana Mitocondrial , Camundongos , Mitocôndrias/metabolismo , Mutação/genética , Doença de Parkinson , Fosforilação , Fosfosserina/metabolismo , Ubiquitina/química , Ubiquitina-Proteína Ligases/genética , Ubiquitinação
7.
Genes Cells ; 18(12): 1131-43, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-24215292

RESUMO

VCP/p97 is a hexameric ring-shaped AAA(+) ATPase that participates in various ubiquitin-associated cellular functions. Mis-sense mutations in VCP gene are associated with the pathogenesis of two inherited diseases: inclusion body myopathy associated with Paget's disease of the bone and front-temporal dementia (IBMPFD) and familial amyotrophic lateral sclerosis (ALS). These pathogenic VCPs have higher affinities for several cofactors, including Npl4, Ufd1 and p47. In Parkin-dependent mitochondrial quality control systems, VCP migrates to damaged mitochondria (e.g., those treated with uncouplers) to aid in the degradation of mitochondrial outer membrane proteins and to eliminate mitochondria. We showed that endogenous Npl4 and p47 also migrate to mitochondria after uncoupler treatment, and Npl4, Ufd1 or p47 silencing causes defective mitochondria clearance after uncoupler treatment. Moreover, pathogenic VCPs show impaired migration to mitochondria, and the exogenous pathogenic VCP expression partially inhibits Npl4 and p47 localization to mitochondria. These results suggest that the increased affinities of pathogenic VCPs for these cofactors cause the impaired movement of pathogenic VCPs. In adult flies, exogenous expression of wild-type VCP, but not pathogenic VCPs, reduces the number of abnormal mitochondria in muscles. Failure of pathogenic VCPs to function on damaged mitochondria may be related to the pathogenesis of IBMPFD and ALS.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Adenosina Trifosfatases/metabolismo , Proteínas de Ciclo Celular/metabolismo , Mitocôndrias/metabolismo , Proteínas Nucleares/metabolismo , Proteínas/metabolismo , Ubiquitina-Proteína Ligases/metabolismo , Proteínas Adaptadoras de Transporte Vesicular , Adenosina Trifosfatases/genética , Esclerose Lateral Amiotrófica/genética , Animais , Animais Geneticamente Modificados , Proteínas de Ciclo Celular/genética , Drosophila , Demência Frontotemporal/genética , Células HeLa , Humanos , Peptídeos e Proteínas de Sinalização Intracelular , Mitocôndrias/patologia , Distrofia Muscular do Cíngulo dos Membros/genética , Mutação de Sentido Incorreto , Miosite de Corpos de Inclusão/genética , Osteíte Deformante/genética , Proteína com Valosina
8.
J Struct Biol ; 179(2): 93-103, 2012 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-22728077

RESUMO

VCP/p97/Cdc48 is a hexameric ring-shaped AAA ATPase that participates in a wide variety of cellular functions. VCP is a very abundant protein in essentially all types of cells and is highly conserved among eukaryotes. To date, 19 different single amino acid-substitutions in VCP have been reported to cause IBMPFD (inclusion body myopathy associated with Paget disease of bone and frontotemporal dementia), an autosomal dominant inherited human disease. Moreover, several similar single amino acid substitutions have been proposed to associate with a rare subclass of familial ALS. The mechanisms by which these mutations contribute to the pathogenesis are unclear. To elucidate potential functional differences between wild-type and pathogenic VCPs, we expressed both VCPs in yeast cdc48 mutants. We observed that all tested pathogenic VCPs suppressed the temperature-sensitive phenotype of cdc48 mutants more efficiently than wild-type VCP. In addition, pathogenic VCPs, but not wild-type VCP, were able to rescue a lethal cdc48 disruption. In yeast, pathogenic VCPs, but not wild-type VCP, formed apparent cytoplasmic foci, and these foci were transported to budding sites by the Myo2/actin-mediated transport machinery. The foci formation of pathogenic VCPs appeared to be associated with their suppression of the temperature-sensitive phenotype of cdc48 mutants. These results support the idea that the pathogenic VCP mutations create dominant gain-of-functions rather than a simple loss of functional VCP. Their unique properties in yeast could provide a convenient drug-screening system for the treatment of these diseases.


Assuntos
Adenosina Trifosfatases/metabolismo , Proteínas de Ciclo Celular/metabolismo , Demência Frontotemporal/enzimologia , Distrofia Muscular do Cíngulo dos Membros/enzimologia , Miosite de Corpos de Inclusão/enzimologia , Osteíte Deformante/enzimologia , Leveduras/enzimologia , Leveduras/crescimento & desenvolvimento , Adenosina Trifosfatases/genética , Proteínas de Ciclo Celular/genética , Citometria de Fluxo , Teste de Complementação Genética , Humanos , Mutação , Proteína com Valosina , Leveduras/genética
9.
Genes Cells ; 14(4): 483-97, 2009 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-19335618

RESUMO

p97/valosin-containing protein (VCP) is a member of the AAA family proteins, which plays various important roles in cells by using its ATPase activity. But mechanism of regulating its ATPase activity is mostly unknown. We report here that VCP is highly modified throughout the protein via acetylation and phosphorylation. In addition to six previously identified phosphorylation sites, we identified at least 14 serines, 14 threonines, 6 tyrosines and 22 lysines as potential modification sites. Interestingly, these sites included Lys251 and Lys524, which are very critical for the ATP binding in Walker A motif of D1 and D2 domains, respectively. It is notable that 16 sites are in the N-terminal region and 16 sites are clustered in D2alpha domain (from Pro646 to Gly765). Indeed, amino acid substitution of Lys696 and Thr761 profoundly affect VCP ATPase activities. From these results, we propose that D2alpha domain acts as a VCP ATPase Regulatory domain or "VAR domain". VCP modifications including those in this VAR domain may endorse adaptive and multiple functions to VCP in different cell conditions such as in the cell cycle and with abnormal protein accumulation.


Assuntos
Adenosina Trifosfatases/metabolismo , Proteínas de Ciclo Celular/metabolismo , Proteínas Recombinantes/metabolismo , Acetilação , Adenosina Trifosfatases/química , Adenosina Trifosfatases/genética , Sequência de Aminoácidos , Animais , Western Blotting , Proteínas de Ciclo Celular/química , Proteínas de Ciclo Celular/genética , Linhagem Celular , Cromatografia Líquida , Eletroforese em Gel Bidimensional , Humanos , Cinética , Lisina/genética , Lisina/metabolismo , Espectrometria de Massas , Dados de Sequência Molecular , Mutação , Fosforilação , Processamento de Proteína Pós-Traducional , Ratos , Proteínas Recombinantes/química , Proteínas Recombinantes/isolamento & purificação , Homologia de Sequência de Aminoácidos , Serina/genética , Serina/metabolismo , Spodoptera , Treonina/genética , Treonina/metabolismo , Tirosina/genética , Tirosina/metabolismo , Proteína com Valosina
11.
Mini Rev Med Chem ; 7(1): 99-106, 2007 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-17266642

RESUMO

Huntington's disease (HD) is a dominantly inherited neurodegenerative disorder caused by expansion of a polyglutamine (polyQ) tract in the huntingtin protein, resulting in intracellular aggregate formation and neurodegeneration. Biochemical pathways leading from polyQ expansion to disease pathogenesis are largely unknown. Recent approaches using genetic models systems have begun to uncover nuclear and cytoplasmic pathologies that represent potential targets for therapeutic intervention.


Assuntos
Doença de Huntington/tratamento farmacológico , Doença de Huntington/prevenção & controle , Peptídeos/metabolismo , Humanos , Doença de Huntington/metabolismo , Doença de Huntington/patologia
12.
J Stroke Cerebrovasc Dis ; 15(6): 277-82, 2006.
Artigo em Inglês | MEDLINE | ID: mdl-17904088

RESUMO

INTRODUCTION: Orengedokuto, a Kampo medicine, is used to treat patients with hypertension and cerebrovascular disease in Japan. One of its effects is thought to be antiplatelet action, but the mechanisms involved are unclear. Therefore, we investigated the effects of Orengedokuto on platelet aggregation and activation. METHODS: Platelet aggregation was determined by measuring light transmission (optical density [OD]) and light scattering intensity. Platelet activation was assessed by flow-cytometric determination of PAC-1+ and CD62P+ platelets. For the in vitro study, blood samples were obtained from 45 patients with cerebral infarction (chronic stage) and 27 magnetic resonance imaging-proven control subjects. Furthermore, Orengedokuto was administered to 10 patients with cerebral infarction for up to 12 months, and its effects on platelet aggregation and activation were evaluated. RESULTS: Orengedokuto dose-dependently inhibited agonist-induced platelet aggregation. In vitro, the OD% (mean +/- SD) after stimulation with 2 mumol/L adenosine diphosphate was decreased from 54.4 +/- 21.0 to 16.0 +/- 14.2 (P < .01) in patients, and from 56.8 +/- 26.9 to 19.8 +/- 18.9 (P < .01) in control subjects (1000 mug/mL Orengedokuto). Similarly, the OD% after 0.5 mug/mL collagen stimulation was decreased from 98.3 +/- 37.0 to 24.8 +/- 27.9 (P < .01) in patients, and from 79.2 +/- 13.8 to 21.5 +/- 21.9 (P < .01) in the control subjects. In the clinical study, platelet aggregation was also significantly decreased (P < .05). Agonist-induced platelet activation was not significantly inhibited by Orengedokuto in vitro, but spontaneous platelet activation in patients after oral administration was reduced from 31.0 +/- 18.3 to 14.2 +/- 8.7 (PAC-1+) and from 11.3 +/- 7.8 to 5.1 +/- 3.9 (CD62+) (P < .05). CONCLUSION: Our results demonstrated inhibitory activity of Orengedokuto on both platelet aggregation and activation at a clinically relevant dose.

13.
J Biol Chem ; 280(50): 41332-41, 2005 Dec 16.
Artigo em Inglês | MEDLINE | ID: mdl-16234241

RESUMO

Valosin-containing protein (p97/VCP) has been proposed as playing crucial roles in a variety of physiological and pathological processes such as cancer and neurodegeneration. We previously showed that VCP(K524A), an ATPase activity-negative VCP mutant, induced vacuolization, accumulation of ubiquitinated proteins, and cell death, phenotypes commonly observed in neurodegenerative disorders. However, any regulatory mechanism of its ATPase activity has not yet been clarified. Here, we show that oxidative stress readily inactivates VCP ATPase activity. With liquid chromatography/tandem mass spectrometry, we found that at least three cysteine residues were modified by oxidative stress. Of them, the 522nd cysteine (Cys-522) was identified as the site responsible for the oxidative inactivation of VCP. VCP(C522T), a single-amino acid substitution mutant from cysteine to threonine, conferred almost complete resistance to the oxidative inactivation. In response to oxidative stress, VCP strengthened the interaction with Npl4 and Ufd1, both of which are essential in endoplasmic reticulum-associated protein degradation. Cys-522 is located in the second ATP binding motif and is highly conserved in multicellular but not unicellular organisms. Cdc48p (yeast VCP) has threonine in the corresponding amino acid, and it showed resistance to the oxidative inactivation in vitro. Furthermore, a yeast mutant (delta cdc48 + cdc48[T532C]) was shown to be susceptible to oxidants-induced growth inhibition and cell death. These results clearly demonstrate that VCP ATPase activity is regulated by the oxidative modification of the Cys-522 residue. This regulatory mechanism may play a key role in the conversion of oxidative stress to endoplasmic reticulum stress response in multicellular organisms and also in the pathological process of various neurodegenerative disorders.


Assuntos
Proteínas de Ciclo Celular/metabolismo , Cisteína/química , Oxigênio/química , Proteínas Adaptadoras de Transporte Vesicular , Adenosina Trifosfatases , Motivos de Aminoácidos , Sequência de Aminoácidos , Animais , Linhagem Celular , Regulador de Condutância Transmembrana em Fibrose Cística/metabolismo , DNA Complementar/metabolismo , Ditiotreitol/farmacologia , Relação Dose-Resposta a Droga , Retículo Endoplasmático/metabolismo , Evolução Molecular , Citometria de Fluxo , Deleção de Genes , Glutationa/química , Humanos , Peptídeos e Proteínas de Sinalização Intracelular , Dados de Sequência Molecular , Mutação , Doenças Neurodegenerativas/metabolismo , Estresse Oxidativo , Fenótipo , Ligação Proteica , Proteínas/metabolismo , Proteínas Recombinantes/química , Homologia de Sequência de Aminoácidos , Treonina/química , Ubiquitina/química , Proteína com Valosina
14.
Tokai J Exp Clin Med ; 30(1): 35-9, 2005 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-15952297

RESUMO

We treated a 59-year-old woman presenting with hemoptysis, a rare symptom of pheochromocytoma. Multiple factors including hypertension caused by sudden catecholamine release may result in pulmonary edema. It should be noted that the increased activation of coagulation cascade, which was demonstrated by increased thrombin-antithrombin III complex (TAT) and prothrombin fragment factor 1 and 2 (F1 + 2), as well as endothelial or platelet stimulation evidenced by the increased plasma von Willebrand factor, may have contributed to hemoptysis. These abnormalities were normalized after adrenalectomy. Our case indicates the important role of catecholamine in coagulopathy and possibly in vasculopathy.


Assuntos
Transtornos da Coagulação Sanguínea/etiologia , Transtornos da Coagulação Sanguínea/patologia , Hemoptise/etiologia , Hemoptise/patologia , Feocromocitoma/complicações , Feocromocitoma/patologia , 3-Iodobenzilguanidina , Transtornos da Coagulação Sanguínea/diagnóstico por imagem , Fatores de Coagulação Sanguínea/metabolismo , Catecolaminas/urina , Feminino , Hemoptise/diagnóstico por imagem , Humanos , Pessoa de Meia-Idade , Feocromocitoma/diagnóstico por imagem , Radiografia , Tomógrafos Computadorizados
15.
Genes Cells ; 9(8): 685-96, 2004 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-15298677

RESUMO

Amyloid-like protein aggregates have been implicated in various diseases and in the protein-based inheritance of yeast prions. The molecular chaperone Hsp104 has been shown to be necessary for the aggregate formation of polyglutamine in yeast, and for the maintenance of several yeast prion phenotypes through the formation of self-propagating aggregates. In this paper, we show that the polyglutamine aggregates that are formed independently of Hsp104, are required for Hsp104 to efficiently produce more aggregates. Similarly, in the yeast prion [PSI+] system, Hsp104-dependent epigenetic changes to the [PSI+] prion phenotype require the presence of prion aggregates in the normal [psi-] state. We also show that the co-localization of different prion aggregates suggests that cross-seeding by different yeast prions increases the probability of Hsp104-dependent epigenetic change. These findings highlight the role of pre-existing aggregates in chaperone-dependent establishment of the epigenetic trait in yeast prions, and possibly in the pathology of several neurodegenerative diseases.


Assuntos
Proteínas de Choque Térmico/metabolismo , Peptídeos/química , Príons/genética , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismo , Epigênese Genética , Deleção de Genes , Proteínas de Choque Térmico/genética , Fatores de Terminação de Peptídeos , Plasmídeos , Príons/análise , Príons/química , Príons/metabolismo , Estrutura Terciária de Proteína , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/ultraestrutura , Proteínas de Saccharomyces cerevisiae/análise , Proteínas de Saccharomyces cerevisiae/química
17.
IUBMB Life ; 55(6): 337-45, 2003 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-12938736

RESUMO

The polyglutamine diseases, a group of diseases currently thought to consist of nine inherited neurodegenerative diseases, are caused by the expansion of unstable CAG trinucleotide repeats that code for polyglutamine tracts in the responsible genes. These diseases are now recognized as being of a type with conformationally abnormal or amyloid-related proteins, and thus are called 'conformational diseases'. Recently, many studies using cell cultures and model organisms have suggested that the two major machineries for protein quality control (the molecular chaperone and the protein degradation machineries) play important roles in the pathogenesis of the polyglutamine diseases. Interestingly, molecular chaperones have been shown to behave in totally different ways in these studies, namely in suppressing as well as enhancing neurodegeneration or cell death. These apparently opposite actions of molecular chaperones suggest that a certain balance between the activities of molecular chaperones and the expression level of polyglutamine is an important determinant of the pathogenesis. In this review, we summarize recent findings on such ambiguous effects of molecular chaperones on polyglutamine diseases, and discuss possible mechanisms by which molecular chaperones, especially VCP, are involved in the pathogenesis.


Assuntos
Chaperonas Moleculares/metabolismo , Doenças Neurodegenerativas/genética , Doenças Neurodegenerativas/metabolismo , Peptídeos , Humanos , Chaperonas Moleculares/genética , Doenças Neurodegenerativas/patologia , Neurotoxinas , Peptídeos/toxicidade , Repetições de Trinucleotídeos/genética
18.
J Biol Chem ; 277(40): 37536-41, 2002 Oct 04.
Artigo em Inglês | MEDLINE | ID: mdl-12161426

RESUMO

Polyglutamine disease is now recognized as one of the conformational, amyloid-related diseases. In this disease, polyglutamine expansion in proteins has toxic effects on cells and also results in the formation of aggregates. Polyglutamine aggregate formation is accompanied by conversion of the polyglutamine from a soluble to an insoluble form. In yeast, the efficiency of the aggregate formation is determined by the balance of various parameters, including the length of the polyglutamine tract, the function of Hsp104, and the level of polyglutamine expression. In this study, we found that the co-expression of a long polyglutamine tract, which formed aggregates independently of the function of Hsp104, enhanced the formation of aggregates of a short polyglutamine tract in wild-type cells as well as in Deltahsp104 mutant cells. Thus, the expression of a long polyglutamine tract would be an additional parameter determining the efficiency of aggregate formation of a short polyglutamine tract. The co-localization of aggregates of long and short polyglutamine tracts suggests the possibility that the enhancement occurs due to the seeding of aggregates of the long polyglutamine tracts.


Assuntos
Chaperonas Moleculares/metabolismo , Peptídeos/genética , Peptídeos/metabolismo , Sequência de Aminoácidos , Amiloidose/genética , Sequência de Bases , Benzotiazóis , Imunofluorescência , Corantes Fluorescentes , Vetores Genéticos , Humanos , Dados de Sequência Molecular , NF-kappa B/metabolismo , Peptídeos/química , Plasmídeos , Polidesoxirribonucleotídeos/química , Proteínas Recombinantes/química , Proteínas Recombinantes/metabolismo , Tiazóis
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