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1.
J Investig Allergol Clin Immunol ; 31(5): 404-416, 2021 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-32301440

RESUMO

BACKGROUND AND OBJECTIVE: Hereditary angioedema with C1-inhibitor deficiency (C1-INH-HAE) and acquired angioedema related to angiotensin-converting enzyme (ACE) inhibitors (ACEI-AAE) are types of bradykinin-mediated angioedema without wheals characterized by recurrent swelling episodes. Recent evidence suggests that a state of "vascular preconditioning" predisposes individuals to attacks, although no data are available on possible structural alterations of the vessels. Objective: This study aims to compare the features of nailfold capillaries to highlight possible structural anomalies between patients affected by C1-INH-HAE and controls and between patients with ACEI-AAE and hypertensive controls. METHODS: We used nailfold videocapillaroscopy (NVC) to assess the following: apical, internal, and external diameter; loop length; intercapillary distance; and capillary density, distribution, and morphology. Plasma levels of vascular endothelial growth factor (VEGF) A, VEGF-C, angiopoietin (Ang) 1, and Ang2 were also measured. RESULTS: Compared with healthy controls (n=28), C1-INH-HAE patients (n = 34) were characterized by significant structural alterations of the capillaries, such as greater intercapillary distance (216 vs 190 µm), increased apical, internal, and external diameter (28 vs 22 µm; 22 vs 20 µm; and 81 vs 65 µm, respectively), decreased density (4 vs 5 capillaries/mm2), more irregular capillary distribution, and more tortuous morphology. Apical diameter was enlarged in patients with ≥12 attacks per year. In ACEI-AAE patients, NVC showed no alterations with respect to hypertensive controls. NVC performed in 2 C1-INH-HAE patients during attacks showed no changes compared with the remission phase. CONCLUSIONS: We detected major structural capillary alterations in C1-INH-HAE patients, thus confirming the involvement of microcirculation in the pathogenesis of angioedema.


Assuntos
Angioedema , Angioedemas Hereditários , Bradicinina , Proteína Inibidora do Complemento C1 , Humanos , Angioscopia Microscópica , Fator A de Crescimento do Endotélio Vascular
2.
J Investig Allergol Clin Immunol ; 30(4): 272-280, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31599724

RESUMO

BACKGROUND AND OBJECTIVE: Angiotensin-converting enzyme inhibitor-associated angioedema (ACEI-AAE) affects 0.1%-0.7% of patients treated with ACEIs. While previous research suggests that angioedema attacks result from increased vascular permeability, the pathogenesis is not completely understood. Objective: This study aimed to describe the clinical, genetic, and laboratory parameters of ACEI-AAE patients and to investigate the role of vascular endothelial growth factors A and C (VEGF-A and VEGF-C), angiopoietins 1 and 2 (Ang1/Ang2), and secretory phospholipase A2 (sPLA2) in the pathogenesis of ACEI-AAE. METHODS: The clinical and laboratory data of ACEI-AAE patients were collected from 2 angioedema reference centers. Healthy volunteers and ACEI-treated patients without angioedema were enrolled to compare laboratory parameters. Genetic analyses to detect mutations in the genes SERPING1, ANGPT1, PLG, and F12 were performed in a subset of patients. RESULTS: A total of 51 patients (57% male) were diagnosed with ACEI-AAE. The average time to onset of symptoms from the start of ACEI therapy was 3 years (range, 30 days-20 years). The most commonly affected sites were the lips (74.5%), tongue (51.9%), and face (41.2%). Switching from ACEIs to sartans was not associated with an increased risk of angioedema in patients with a history of ACEIAAE. VEGF-A, VEGF-C, and sPLA2 plasma levels were higher in ACEI-AAE patients than in the controls. Ang1/2 concentrations remained unchanged. No mutations were detected in the genes analyzed. CONCLUSIONS: Our data suggest that sartans are a safe therapeutic alternative in ACEI-AAE patients. Increased concentrations of VEGF-A, VEGF-C, and sPLA2 in ACEI-AAE patients suggest a possible role of these mediators in the pathogenesis of ACEI-AAE.


Assuntos
Angioedema/imunologia , Inibidores da Enzima Conversora de Angiotensina/efeitos adversos , Antígenos de Plaquetas Humanas/sangue , Fator A de Crescimento do Endotélio Vascular/sangue , Fator C de Crescimento do Endotélio Vascular/sangue , Adulto , Idoso , Idoso de 80 Anos ou mais , Angiopoietina-1/sangue , Angiopoietina-2/sangue , Bloqueadores do Receptor Tipo 1 de Angiotensina II/uso terapêutico , Inibidores da Enzima Conversora de Angiotensina/uso terapêutico , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Risco , Troca de Tratamento , Regulação para Cima
4.
Allergy ; 71(7): 989-96, 2016 07.
Artigo em Inglês | MEDLINE | ID: mdl-26873113

RESUMO

BACKGROUND: Hereditary angioedema with C1 inhibitor deficiency (C1-INH-HAE) is a rare inherited genetic disease characterized by recurrent swelling episodes of the skin, gastrointestinal tract, and upper airways. Angioedema attacks result from increased vascular permeability due to the release of bradykinin from high molecular weight kininogen. Currently, there are no biomarkers predicting the frequency of angioedema attacks. Vascular permeability is modulated by several factors, including vascular endothelial growth factors (VEGFs) and angiopoietins (Angs). As increased circulating levels of VEGFs and Angs have been observed in diseases associated with higher vascular permeability (e.g., systemic capillary leak syndrome and sepsis), we sought to analyze plasma concentrations of VEGFs and Angs in patients with C1-INH-HAE. METHODS: Sixty-eight healthy controls and 128 patients with C1-INH-HAE were studied. Concentrations of angiogenic (VEGF-A, Ang1, Ang2), anti-angiogenic (VEGF-A165b ) and lymphangiogenic (VEGF-C) factors were evaluated by ELISA. C1-INH functional activity was assessed by EIA. RESULTS: Plasma concentrations of VEGF-A, VEGF-C, Ang1, and Ang2 were higher in patients with C1-INH-HAE in remission than in healthy controls. Concentration of VEGF-A was further increased in patients with lower C1-INH functional activity. Patients with C1-INH-HAE experiencing more than 12 angioedema attacks per year were characterized by higher plasma levels of VEGF-A, VEGF-C, and Ang2 compared with the other patients. CONCLUSIONS: We hypothesize that VEGFs and Angs induce a state of 'vascular preconditioning' that may predispose to angioedema attacks. In addition, the identification of increased plasma levels of VEGFs and Angs in patients with C1-INH-HAE may prompt the investigation of VEGFs and Angs as biomarkers of C1-INH-HAE severity.


Assuntos
Angioedema Hereditário Tipos I e II/sangue , Fator A de Crescimento do Endotélio Vascular/sangue , Adolescente , Adulto , Angiopoietina-1/sangue , Angiopoietina-2/sangue , Biomarcadores , Estudos de Casos e Controles , Criança , Pré-Escolar , Progressão da Doença , Feminino , Angioedema Hereditário Tipos I e II/diagnóstico , Angioedema Hereditário Tipos I e II/prevenção & controle , Humanos , Masculino , Pessoa de Meia-Idade , Índice de Gravidade de Doença , Fator C de Crescimento do Endotélio Vascular/sangue , Adulto Jovem
5.
Biochem Genet ; 51(11-12): 967-75, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-23857551

RESUMO

Cytokines act as pleiotropic polypeptides able to regulate inflammatory/immune responses and to provide important signals in physiological and pathological processes. Several cytokines (Th1, Th2, and Th17) seem to be involved in the pathophysiology of Behçet's disease, a chronic immune-mediated disease characterized by oral and genital lesions and ocular inflammation. Its individual susceptibility seems to be modulated by genetic variants in genes codifying these cytokines. Th1 and Th17 seem to be involved in the disease's active phases, and Th2 seems to affect the development or severity of the disease; however, contrasting data are reported. In this study, some genetic variants of the Th1/Th2 cytokine genes were investigated in Sicilian patients and age- and gender-matched controls. Three very significant associations with Behçet's disease were detected, and combined genotypes associated with increased disease risk were identified. Results obtained point to the key role of Th1/Th2 cytokine genetic variants in disease susceptibility.


Assuntos
Síndrome de Behçet/genética , Síndrome de Behçet/imunologia , Interleucinas/genética , Adulto , Síndrome de Behçet/patologia , Feminino , Frequência do Gene , Variação Genética , Genótipo , Humanos , Interleucinas/imunologia , Masculino , Pessoa de Meia-Idade , Projetos Piloto , Polimorfismo de Nucleotídeo Único , Sicília , Adulto Jovem
6.
Allergy ; 67(8): 1074-7, 2012 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-22686628

RESUMO

Icatibant, a bradykinin B2 receptor antagonist, is an established treatment for acute attacks of hereditary angioedema (HAE) with C1-inhibitor (C1-INH) deficiency. We describe our experience with icatibant in eight patients with angioedema because of acquired C1-INH deficiency (AAE). Forty-eight moderate-to-severe attacks were treated with subcutaneous icatibant 30 mg; two moderate attacks resolved without treatment. The median (range) duration of treated attacks (onset to complete resolution) was 9.33 (1.67-39.00) h; durations of the untreated attacks were 72 and 96 h. Symptom improvement following icatibant treatment occurred in 0.5 (0.25-2.10) h and complete resolution in 6.75 (0.50-30.75) h. A single icatibant injection achieved complete symptom resolution in 47 attacks; one facial attack required a second injection. One peripheral attack responded less quickly than other treated attacks. Five patients reported transient injection site reactions. Icatibant appeared to provide effective symptom relief and was generally well tolerated.


Assuntos
Antagonistas Adrenérgicos beta/uso terapêutico , Angioedema/tratamento farmacológico , Angioedema/imunologia , Bradicinina/análogos & derivados , Proteína Inibidora do Complemento C1/imunologia , Idoso , Idoso de 80 Anos ou mais , Autoanticorpos/imunologia , Doenças Autoimunes/tratamento farmacológico , Doenças Autoimunes/imunologia , Bradicinina/uso terapêutico , Antagonistas de Receptor B2 da Bradicinina , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Resultado do Tratamento
8.
Ceska Gynekol ; 76(4): 274-9, 2011 Sep.
Artigo em Sk | MEDLINE | ID: mdl-22026068

RESUMO

OBJECTIVE: To evaluate the usefullness of examination of methylation status of selected tumor-supressor genes in early diagnosis of ovarian cancer. DESIGN: Prospective clinical study. SETTING: Department of Gynecology and Obstetrics, Department of Molecular Biology, Jessenius Medical Faculty, Commenius University, Martin, Slovak Republic. METHODS: In this study we analyzed hypermethylation of 5 genes RASSF1A, GSTP, E-cadherin, p16 and APC in ovarian tumor samples from 34 patients - 13 patients with epithelial ovarian cancer, 2 patients with border-line ovarian tumors, 12 patients with benign lesions of ovaries and 7 patients with healthy ovarian tissue. The methylation status of promoter region of tumor-supressor genes was determined by Methylation Specific Polymerase Chain Reaction (MSP) using a nested two-step approach with bisulfite modified DNA template and specific primers. RESULTS: Gene methylation analysis revealed hypermethylation of gene RASSF1A (46%) and GSTP (8%) only in malignant ovarian tissue samples. Ecad, p16 and APC genes were methylated both in maignant and benign tissue samples. Methylation positivity in observed genes was present independently to all clinical stages of ovarian cancer and to tumor grades. However, there was observed a trend of increased number and selective involvement of methylated genes with increasing disease stages. Furthermore, there was no association between positive methylation status and histological subtypes of ovarian carcinomas. CONCLUSION: RASSF1A and GSTP promoter methylation positivity is associated with ovarian cancer. The revealed gene-selective methylation positivity and the increased number of methylated genes with advancing disease stages could be considered as a useful molecular marker for early detection of ovarian cancer. However, there is need to find diagnostic approach of specifically and frequently methylated genes to determining a methylation phenotype for early detection of ovarian malignancies.


Assuntos
Metilação de DNA , Genes Supressores de Tumor , Neoplasias Ovarianas/genética , Adulto , Idoso , Carcinoma Epitelial do Ovário , Feminino , Humanos , Pessoa de Meia-Idade , Neoplasias Epiteliais e Glandulares/genética , Reação em Cadeia da Polimerase , Regiões Promotoras Genéticas
9.
J. investig. allergol. clin. immunol ; 31(5): 404-416, 2021. tab, graf
Artigo em Inglês | IBECS (Espanha) | ID: ibc-216383

RESUMO

Background: Hereditary angioedema with C1-inhibitor deficiency (C1-INH-HAE) and acquired angioedema related to angiotensin-converting enzyme (ACE) inhibitors (ACEI-AAE) are types of bradykinin-mediated angioedema without wheals characterized by recurrent swelling episodes. Recent evidence suggests that a state of “vascular preconditioning” predisposes individuals to attacks, although no data are available on possible structural alterations of the vessels. Objective: This study aims to compare the features of nailfold capillaries to highlight possible structural anomalies between patients affected by C1-INH-HAE and controls and between patients with ACEI-AAE and hypertensive controls.Methods: We used nailfold videocapillaroscopy (NVC) to assess the following: apical, internal, and external diameter; loop length; intercapillary distance; and capillary density, distribution, and morphology. Plasma levels of vascular endothelial growth factor (VEGF) A, VEGF-C, angiopoietin (Ang) 1, and Ang2 were also measured. Results: Compared with healthy controls (n=28), C1-INH-HAE patients (n = 34) were characterized by significant structural alterations of the capillaries, such as greater intercapillary distance (216 vs 190 μm), increased apical, internal, and external diameter (28 vs 22 μm; 22 vs 20 μm; and 81 vs 65 μm, respectively), decreased density (4 vs 5 capillaries/mm2), more irregular capillary distribution, and more tortuous morphology. Apical diameter was enlarged in patients with ≥12 attacks per year. In ACEI-AAE patients, NVC showed no alterations with respect to hypertensive controls. NVC performed in 2 C1-INH-HAE patients during attacks showed no changes compared with the remission phase. Conclusions: We detected major structural capillary alterations in C1-INH-HAE patients, thus confirming the involvement of microcirculation in the pathogenesis of angioedema (AU)


Antecedentes: Tanto el angioedema hereditario con deficiencia de inhibidor del C1 (C1-INH-HAE) como el angioedema adquiridorelacionado con los inhibidores de la ECA (ACEI-AAE), son dos tipos de angioedema mediados por bradicinina que cursan con episodiosde inflamación recurrente sin acompañarse de habones. Existe evidencia de la existencia de un estado de "preacondicionamiento vascular"que predispone a estos pacientes a los ataques, pero no hay datos disponibles sobre las posibles alteraciones estructurales de los vasos.Objetivo: Este estudio tiene como objetivo el evaluar las características de los capilares de la base ungueal para identificar posiblesanomalías estructurales en los pacientes afectados por C1-INH-HAE en comparación con la población sana, y en los pacientes con ACEIAAE en comparación con controles con hipertensión arterial.Métodos: Mediante videocapilaroscopia de la base ungueal (NVC), se evaluaron: los diámetros apical, interno y externo, la longitud delasa, la distancia intercapilar, la densidad capilar, su distribución y su morfología. También se midieron los niveles plasmáticos del factorde crecimiento endotelial vascular (VEGF)-A, VEGF-C, angiopoyetina (Ang)1 y Ang2.Resultados: En los pacientes con C1-INH-HAE (n = 34) se observaron alteraciones estructurales de los capilares significativas, en comparacióncon los controles sanos (n = 28): mayor distancia intercapilar (216 frente a 190 µm), aumento del diámetro apical, interno y externo(28 frente a 22 µm; 22 frente a 20 µm; y 81 frente a 65 µm, respectivamente), disminución de la densidad (4 frente a 5 capilares/mm2),distribución capilar más irregular y una morfología más tortuosa. El diámetro apical fue mayor en aquellos pacientes con ≥12 ataques/año. En los pacientes con ACEI-AAE, las NVC no mostraron alteraciones al ser comparadas con las de los controles hipertensos. Las NVC realizadas en dos pacientes ...(AU)


Assuntos
Humanos , Masculino , Feminino , Criança , Adolescente , Adulto Jovem , Adulto , Pessoa de Meia-Idade , Idoso , Angioedema/diagnóstico , Proteína Inibidora do Complemento C1 , Fator A de Crescimento do Endotélio Vascular , Angioscopia Microscópica , Estudos de Casos e Controles
10.
J Mol Biol ; 298(2): 261-72, 2000 Apr 28.
Artigo em Inglês | MEDLINE | ID: mdl-10764595

RESUMO

The small heat-shock proteins (sHSPs) form a diverse family of proteins that are produced in all organisms. They function as chaperone-like proteins in that they bind unfolded polypeptides and prevent uncontrolled protein aggregation. Here, we present parallel cryo-electron microscopy studies of five different sHSP assemblies: Methanococcus jannaschii HSP16.5, human alphaB-crystallin, human HSP27, bovine native alpha-crystallin, and the complex of alphaB-crystallin and unfolded alpha-lactalbumin. Gel-filtration chromatography indicated that HSP16.5 is the most monodisperse, while HSP27 and the alpha-crystallin assemblies are more polydisperse. Particle images revealed a similar trend showing mostly regular and symmetric assemblies for HSP16.5 particles and the most irregular assemblies with a wide range of diameters for HSP27. A symmetry test on the particle images indicated stronger octahedral symmetry for HSP16.5 than for HSP27 or the alpha-crystallin assemblies. A single particle reconstruction of HSP16.5, based on 5772 particle images with imposed octahedral symmetry, resulted in a structure that closely matched the crystal structure. In addition, the cryo-EM reconstruction revealed internal density presumably corresponding to the flexible 32 N-terminal residues that were not observed in the crystal structure. The N termini were found to partially fill the central cavity making it unlikely that HSP16.5 sequesters denatured proteins in the cavity. A reconstruction calculated without imposed symmetry confirmed the presence of at least loose octahedral symmetry for HSP16.5 in contrast to the other sHSPs examined, which displayed no clear overall symmetry. Asymmetric reconstructions for the alpha-crystallin assemblies, with an additional mass selection step during image processing, resulted in lower resolution structures. We interpret the alpha-crystallin reconstructions to be average representations of variable assemblies and suggest that the resolutions achieved indicate the degree of variability. Quaternary structural information derived from cryo-electron microscopy is related to recent EPR studies of the alpha-crystallin domain fold and dimer interface of alphaA-crystallin.


Assuntos
Proteínas de Choque Térmico/química , Proteínas de Choque Térmico/ultraestrutura , Animais , Proteínas Arqueais , Bovinos , Cromatografia em Gel , Microscopia Crioeletrônica , Cristalinas/química , Cristalinas/metabolismo , Cristalinas/ultraestrutura , Cristalografia por Raios X , Proteínas de Choque Térmico/metabolismo , Humanos , Lactalbumina/química , Lactalbumina/metabolismo , Lactalbumina/ultraestrutura , Mathanococcus/química , Modelos Moleculares , Peso Molecular , Maleabilidade , Estrutura Quaternária de Proteína
11.
J Med Chem ; 36(18): 2666-70, 1993 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-7692046

RESUMO

Arginine is oxidized by a class of enzymes called the nitric oxide synthases (NOS) to generate citrulline and, presumably, nitric oxide (.NO). N-Hydroxylation of a guanidinium nitrogen of arginine to generate N-hydroxyarginine (NOHA) has been shown to be a step in the biosynthesis of .NO. In an effort to elucidate the mechanism by which further oxidation of NOHA occurs, the oxidation of a model N-hydroxyguanidine compound by several peracids was studied in depth. This oxidative chemistry is a possible model for the enzymatic process since the corresponding urea (or citrulline equivalent product) is obtained along with an oxidized nitrogen species. The oxidized nitrogen product was, however, not .NO but rather HNO. .NO generation in this chemical system and in the enzymatic process would require another one-electron oxidation. The mechanistic details of this are further discussed.


Assuntos
Amidinas/química , Aminoácido Oxirredutases/metabolismo , Arginina/análogos & derivados , Clorobenzoatos/química , Modelos Químicos , Piperidinas/química , Arginina/metabolismo , Cromatografia Gasosa , Cromatografia Líquida de Alta Pressão , Temperatura Alta , Medições Luminescentes , Óxido Nítrico/química , Óxido Nítrico Sintase , Oxirredução
12.
Int J Biol Macromol ; 22(3-4): 263-9, 1998.
Artigo em Inglês | MEDLINE | ID: mdl-9650081

RESUMO

A recent paper by Plater et al. [20], showed that the mutation of a single phenylalanine residue F27R in mouse alpha B completely abolished the chaperone-like property of alpha-crystallin when assayed with insulin at 25 degrees C or with gamma-crystallin at 66 degrees C. We have produced the same mutation as well as some additional mutations in human alpha B-crystallin. Our data suggest that the F27R mutation effected the thermal stability of alpha B-crystallin making it unstable at temperatures > or = 60 degrees C. In agreement with the published work, at these temperatures the F27R human recombinant alpha B-crystallin does not protect the target protein from aggregation. When assayed with insulin or alpha-lactalbumin at 25 or 37 degrees C, however, there were no differences in the protective abilities between the native alpha B-crystallin or the F27R mutated human alpha B-crystallin. Several other multiple mutations involving proline residues were also produced. These mutations did not effect the chaperone-like properties of human alpha B-crystallin, but some of them did effect the native molecular weight size as judged by gel filtration chromatography.


Assuntos
Cristalinas/genética , Cristalinas/metabolismo , Chaperonas Moleculares/genética , Chaperonas Moleculares/metabolismo , Mutação Puntual , Animais , Sequência de Bases , Sítios de Ligação/genética , Bovinos , Dicroísmo Circular , Cristalinas/química , Primers do DNA/genética , Estabilidade de Medicamentos , Humanos , Técnicas In Vitro , Lactalbumina/química , Lactalbumina/metabolismo , Camundongos , Chaperonas Moleculares/química , Peso Molecular , Mutagênese Sítio-Dirigida , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Temperatura
13.
G Ital Med Lav Ergon ; 25 Suppl(3): 83-4, 2003.
Artigo em Italiano | MEDLINE | ID: mdl-14979095

RESUMO

The 626/94 Decree amendment (see Decree 25/2002) regard a series of mandatory measures towards the exposure estimation both for future prevention activities as well as for the efficacy evaluation of measures that have already been carried out. This publication provides an updating on a study of the ten-year follow-up regarding occupational exposure to Cr (VI) in workers exposed to low levels of cromium.


Assuntos
Cromo/toxicidade , Exposição Ocupacional/efeitos adversos , Seguimentos , Humanos , Pessoa de Meia-Idade , Vigilância da População , Fatores de Tempo
14.
G Ital Med Lav Ergon ; 25 Suppl(3): 188-9, 2003.
Artigo em Italiano | MEDLINE | ID: mdl-14979143

RESUMO

The problems of the use/abuse of alcohol need a special attention by the Public Authorities, based on the scientific evidences related to the subject. We would like to define in the present paper the procedures for alcohol testing (and drug testing) in the sailors, following the international aviation authorities (ICAO, JAR-OPS-1, FAA) recommendations. A Working Group was established to study both the scientific and the legal aspects of the problems related to alcohol testing in Italy. Experts from the Università "La Sapienza" and from Alitalia studied the alcohol testing issues abroad to set out criteria, guidelines and procedures for random testing in Italy.


Assuntos
Medicina Aeroespacial , Consumo de Bebidas Alcoólicas , Etanol/sangue , Detecção do Abuso de Substâncias/métodos , Humanos , Itália
15.
Akush Ginekol (Sofiia) ; 40(4): 48-9, 2000.
Artigo em Búlgaro | MEDLINE | ID: mdl-11288637

RESUMO

The authors describe a case of a newborn baby with inborn laryngomucocaele, living 14 days after birth. The newborn baby was looked after with artifical lentilation. Because of the inability of self breathing the baby underwent tracheostomia. The autopsy revealed the presence of laryngomucocaele.


Assuntos
Doenças da Laringe/congênito , Mucocele/congênito , Adulto , Evolução Fatal , Feminino , Humanos , Recém-Nascido , Doenças da Laringe/patologia , Masculino , Mucocele/patologia , Gravidez
16.
Nat Commun ; 4: 1982, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23770887

RESUMO

Parkin is a RING-between-RING E3 ligase that functions in the covalent attachment of ubiquitin to specific substrates, and mutations in Parkin are linked to Parkinson's disease, cancer and mycobacterial infection. The RING-between-RING family of E3 ligases are suggested to function with a canonical RING domain and a catalytic cysteine residue usually restricted to HECT E3 ligases, thus termed 'RING/HECT hybrid' enzymes. Here we present the 1.58 Å structure of Parkin-R0RBR, revealing the fold architecture for the four RING domains, and several unpredicted interfaces. Examination of the Parkin active site suggests a catalytic network consisting of C431 and H433. In cells, mutation of C431 eliminates Parkin-catalysed degradation of mitochondria, and capture of an ubiquitin oxyester confirms C431 as Parkin's cellular active site. Our data confirm that Parkin is a RING/HECT hybrid, and provide the first crystal structure of an RING-between-RING E3 ligase at atomic resolution, providing insight into this disease-related protein.


Assuntos
Ubiquitina-Proteína Ligases/química , Ubiquitina-Proteína Ligases/metabolismo , Biocatálise , Domínio Catalítico , Humanos , Mitocôndrias/metabolismo , Modelos Moleculares , Mutação , Doença de Parkinson/enzimologia , Doença de Parkinson/genética , Fenilalanina , Estrutura Terciária de Proteína
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