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1.
Arthritis Care Res (Hoboken) ; 74(10): 1585-1592, 2022 10.
Artículo en Inglés | MEDLINE | ID: mdl-33938161

RESUMEN

OBJECTIVE: The aim of this study was to quantify costs of hospital-associated care for juvenile idiopathic arthritis (JIA), provide insights in patient-level variation in costs, and investigate costs over time from the moment of JIA diagnosis. Results were reported for all JIA patients in general and by subtype. METHODS: This study was a single-center, retrospective analysis of prospective data from electronic medical records of children with JIA, ages 0-18 years, between April 1, 2011 and March 31, 2019. Patient characteristics (age, sex, JIA subtype) and hospital-based resource use (consultations, medication, radiology procedures, laboratory testing, surgeries, emergency department [ED] visits, hospital stays) were extracted and analyzed. Unit prices were obtained from Dutch reimbursement lists and pharmaceutical and hospital list prices. RESULTS: The analysis included 691 patients. The mean total cost of hospital care was €3,784/patient/year, of which €2,103 (55.6%) was attributable to medication. Other costs involved pediatric rheumatologist visits (€633/patient/year [16.7%]), hospital stays (€439/patient/year [11.6%]), other within-hospital specialist visits (€324/patient/year [8.6%]), radiology procedures (€119/patient/year [3.1%]), laboratory tests (€114/patient/year [3.0%]), surgeries (€46/patient/year [1.2%]), and ED visits (€6/patient/year [0.2%]). Mean annual total costs varied between JIA subtypes and between individuals and were the highest for systemic JIA (€7,772/patient/year). Over the treatment course, costs were the highest in the first month after JIA diagnosis. CONCLUSION: Hospital care costs of JIA vary substantially between individuals, between subtypes, and over the treatment course. The highest annual costs were for systemic JIA, primarily attributable to medication (i.e., biologics). Costs of other hospital-associated care were comparable regardless of subtype.


Asunto(s)
Artritis Juvenil , Productos Biológicos , Adolescente , Artritis Juvenil/tratamiento farmacológico , Artritis Juvenil/terapia , Productos Biológicos/uso terapéutico , Niño , Preescolar , Costos de la Atención en Salud , Hospitales , Humanos , Lactante , Recién Nacido , Preparaciones Farmacéuticas , Estudios Prospectivos , Estudios Retrospectivos
2.
Mol Oncol ; 15(12): 3348-3362, 2021 12.
Artículo en Inglés | MEDLINE | ID: mdl-34510716

RESUMEN

Consensus molecular subtypes (CMSs) can guide precision treatment of colorectal cancer (CRC). We aim to identify methylation markers to distinguish between CMS2 and CMS3 in patients with CRC, for which an easy test is currently lacking. To this aim, fresh-frozen tumor tissue of 239 patients with stage I-III CRC was analyzed. Methylation profiles were obtained using the Infinium HumanMethylation450 BeadChip. We performed adaptive group-regularized logistic ridge regression with post hoc group-weighted elastic net marker selection to build prediction models for classification of CMS2 and CMS3. The Cancer Genome Atlas (TCGA) data were used for validation. Group regularization of the probes was done based on their location either relative to a CpG island or relative to a gene present in the CMS classifier, resulting in two different prediction models and subsequently different marker panels. For both panels, even when using only five markers, accuracies were > 90% in our cohort and in the TCGA validation set. Our methylation marker panel accurately distinguishes between CMS2 and CMS3. This enables development of a targeted assay to provide a robust and clinically relevant classification tool for CRC patients.


Asunto(s)
Neoplasias Colorrectales , Metilación de ADN , Biomarcadores de Tumor/genética , Neoplasias Colorrectales/genética , Neoplasias Colorrectales/patología , Islas de CpG/genética , Metilación de ADN/genética , Humanos
4.
Cancers (Basel) ; 13(8)2021 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-33920880

RESUMEN

Circular RNAs (circRNAs) appear important in tumor progression of colon cancer (CC). We identified an extensive catalog of circRNAs in 181 chemonaive stage I/II colon tumors, who underwent curative surgery between 2007 and 2014. We identified circRNAs from RNAseq data, investigated common biology related to circRNA expression, and studied the association between circRNAs and relapse status, tumor stage, consensus molecular subtypes (CMS), tumor localization and microsatellite instability (MSI). We identified 2606 unique circRNAs. 277 circRNAs (derived from 260 genes) were repeatedly occurring in at least 20 patients of which 153 showed a poor or even negative (R < 0.3) correlation with the expression level of their linear gene. The circular junctions for circSATB2, circFGD6, circKMT2C and circPLEKHM3 were validated by Sanger sequencing. Multiple correspondence analysis showed that circRNAs were often co-expressed and that high diversity in circRNAs was associated with favorable disease-free survival (DFS), which was confirmed by Cox regression analysis (Hazard Ratio (HR) 0.60, 95% CI 0.38-0.97, p = 0.036). Considering individual circRNAs, absence of circMGA was significantly associated with relapse, whereas circSATB2, circNAB1, and circCEP192 were associated with both MSI and CMS. This study represents a showcase of the potential clinical utility of circRNAs for prognostic stratification in patients with stage I-II colon cancer and demonstrated that high diversity in circRNAs is associated with favorable DFS.

5.
World J Surg Oncol ; 19(1): 96, 2021 Apr 05.
Artículo en Inglés | MEDLINE | ID: mdl-33820567

RESUMEN

BACKGROUND: Colorectal cancer is the third most common type of cancer in the world. We characterize a cohort of patients who survived up to 5 years without recurrence and identify factors predicting the probability of cure. METHODS: We analyzed data of patients who underwent curative intent surgery for stage I-III CRC between 2007 and 2012 and who had had been included in a large multicenter study in the Netherlands. Cure was defined as 5-year survival without recurrence. Survival data were retrieved from a national registry. RESULTS: Analysis of data of 754 patients revealed a cure rate of 65% (n = 490). Patients with stage I disease and T1- and N0-tumor had the highest probability of cure (94%, 95% and 90%, respectively). Those with a T4-tumor or N2-tumor had the lowest probability of cure (62% and 50%, respectively). A peak in the mortality rate for older patients early in follow-up suggests early excess mortality as an explanation. A similar trend was observed for stage III disease, poor tumor grade, postoperative complications, sarcopenia, and R1 resections. Patients with stage III disease, poor tumor grade, postoperative complications, sarcopenia, and R1 resections show a similar trend for decrease in CSS deaths over time. CONCLUSION: In the studied cohort, the probability of cure for patients with stage I-III CRC ranged from 50 to 95%. Even though most patients will be cured from CRC with standard therapy, standard therapy is insufficient for those with poor prognostic factors, such as high T- and N-stage and poor differentiation grade.


Asunto(s)
Neoplasias del Colon , Neoplasias Colorrectales , Neoplasias Colorrectales/patología , Neoplasias Colorrectales/cirugía , Humanos , Recurrencia Local de Neoplasia/epidemiología , Recurrencia Local de Neoplasia/patología , Recurrencia Local de Neoplasia/cirugía , Estadificación de Neoplasias , Pronóstico , Estudios Prospectivos , Estudios Retrospectivos
6.
J Surg Oncol ; 123(4): 1005-1014, 2021 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-33368279

RESUMEN

BACKGROUND: Although the prognostic relevance of KRAS status in metastatic colorectal cancer (CRC) depends on tumor laterality, this relationship is largely unknown in non-metastatic CRC. METHODS: Patients who underwent resection for non-metastatic CRC between 2000 and 2018 were identified from institutional databases at six academic tertiary centers in Europe and Japan. The prognostic relevance of KRAS status in patients with right-sided (RS), left-sided (LS), and rectal cancers was assessed. RESULTS: Of the 1093 eligible patients, 378 had right-sided tumors and 715 had left-sided tumors. Among patients with RS tumors, the 5-year overall (OS) and recurrence-free survival (RFS) for patients with KRASmut versus wild-type tumors was not shown to differ significantly (82.2% vs. 83.2% and 72.1% vs. 76.7%, respectively, all p > .05). Among those with LS tumors, KRAS mutation was associated with shorter 5-year OS and RFS on both the univariable (OS: 79.4% vs. 86.1%, p = .004; RFS: 68.8% vs. 77.3%, p = .005) and multivariable analysis (OS: HR: 1.52, p = .019; RFS: HR: 1.32, p = .05). CONCLUSIONS: KRAS mutation status was independently prognostic among patients with LS tumors, but this association failed to reach statistical significance in RS and rectal tumors. These findings confirm reports in metastatic CRC and underline the possible biologic importance of tumor location.


Asunto(s)
Neoplasias Colorrectales/patología , Cirugía Colorrectal/mortalidad , Repeticiones de Microsatélite , Mutación , Recurrencia Local de Neoplasia/patología , Proteínas Proto-Oncogénicas B-raf/genética , Proteínas Proto-Oncogénicas p21(ras)/genética , Anciano , Biomarcadores de Tumor/genética , Neoplasias Colorrectales/genética , Neoplasias Colorrectales/cirugía , Femenino , Estudios de Seguimiento , Humanos , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/secundario , Neoplasias Hepáticas/cirugía , Masculino , Persona de Mediana Edad , Recurrencia Local de Neoplasia/genética , Recurrencia Local de Neoplasia/cirugía , Pronóstico , Estudios Retrospectivos , Tasa de Supervivencia
7.
Pediatr Res ; 59(3): 365-70, 2006 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-16492973

RESUMEN

Children with hereditary tyrosinemia type 1 (HT1) suffer from liver failure, renal tubular dysfunction, and rickets. The disease is caused by deficiency of fumarylacetoacetate hydrolase (FAH), the last enzyme of tyrosine catabolism, and leads to accumulation of the toxic substrate fumarylacetoacetate (FAA) in hepatocytes and renal proximal tubular cells. Patients are treated with 2-(2-nitro-4-trifluoro-methylbenzoyl)-1,3 cyclohexanedione (NTBC), which prevents accumulation of FAA by blocking an enzyme upstream of FAH. Liver transplantation is performed when patients do not respond to NTBC or develop hepatocellular carcinoma. This reduces the tyrosine load for the kidney but does not abolish renal exposure to locally produced FAA. To investigate the pathogenesis of liver and kidney damage induced by tyrosine metabolites, we challenged FAH-deficient mice with various doses of homogentisic acid (HGA), a precursor of FAA. Injecting NTBC-treated Fah-/- mice with low doses of HGA caused renal damage and death of renal tubular cells, as was shown by histologic analyses and deoxynucleotidyl transferase-mediated dUDP nick-end labeling (TUNEL) assay but did not lead to liver damage. In addition, kidney function, but not liver function, was affected after exposure to low doses of HGA. Administration of high doses of HGA led to massive cell death in both the liver and kidneys. Resistance to HGA-induced cell death was seen after withdrawing NTBC from Fah-/- mice. The finding that the kidneys of Fah-/- mice are especially sensitive to damage induced by low doses of HGA underscores the need to perform careful monitoring of the kidney function of tyrosinemia patients undergoing any form of treatment.


Asunto(s)
Ciclohexanonas/farmacología , Inhibidores Enzimáticos/farmacología , Ácido Homogentísico/farmacología , Riñón/efectos de los fármacos , Nitrobenzoatos/farmacología , Tirosinemias/metabolismo , 4-Hidroxifenilpiruvato Dioxigenasa/antagonistas & inhibidores , Animales , Ciclohexanonas/metabolismo , Ciclohexanonas/uso terapéutico , Inhibidores Enzimáticos/metabolismo , Inhibidores Enzimáticos/uso terapéutico , Femenino , Ácido Homogentísico/metabolismo , Humanos , Hidrolasas/genética , Hidrolasas/metabolismo , Etiquetado Corte-Fin in Situ , Riñón/citología , Riñón/metabolismo , Riñón/patología , Hígado/citología , Hígado/efectos de los fármacos , Hígado/metabolismo , Hígado/patología , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Nitrobenzoatos/metabolismo , Nitrobenzoatos/uso terapéutico , Tirosinemias/tratamiento farmacológico
8.
J Pediatr ; 146(5): 706-8, 2005 May.
Artículo en Inglés | MEDLINE | ID: mdl-15870679

RESUMEN

Fatty acids play an important role in regulating insulin secretion, but the mechanisms are unclear. We report a case of a novel splice site mutation in the short-chain 3-hydroxyacyl-CoA dehydrogenase (SCHAD) gene associated with hyperinsulinism. This mutation resulted in a nearly complete absence of immunoreactive protein and a decrease in fibroblast SCHAD activity.


Asunto(s)
3-Hidroxiacil-CoA Deshidrogenasas/genética , Hiperinsulinismo/genética , 3-Hidroxiacil-CoA Deshidrogenasas/metabolismo , Clorotiazida/uso terapéutico , Diazóxido/uso terapéutico , Diuréticos , Humanos , Hiperinsulinismo/tratamiento farmacológico , Lactante , Masculino , Mutación Puntual , Inhibidores de los Simportadores del Cloruro de Sodio/uso terapéutico
9.
Pediatr Res ; 56(6): 981-7, 2004 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-15496606

RESUMEN

Mutations in ATP8B1 are associated with FIC1 disease, an autosomal recessive disorder in which intrahepatic cholestasis is the predominant manifestation. ATP8B1 encodes FIC1, which is expressed in several tissues, most prominently in the intestine, pancreas, and stomach and, to a much lesser extent, in the liver. In this study, Fic1 localization and expression during postnatal development was examined in healthy mice. Immunoblot and RT-PCR analysis indicated Fic1 is expressed abundantly in regions of the adult gastrointestinal tract of humans and mice. Immunohistochemistry revealed that Fic1 was localized to the apical membranes of enterocytes, pancreatic acinar cells, gastric pit epithelial cells, and hepatocytes and cholangiocytes. Subsequent analysis of early postnatal expression revealed that Fic1 expression in the small intestine was limited or absent at the age of 7 and 14 d and increased significantly with maturation. In contrast, pancreatic, hepatic, and gastric Fic1 expression was not diminished during the first 3 wk of postnatal development. In conclusion, these data show that Fic1 is expressed in a tissue-specific and developmentally regulated fashion at the apical membranes of epithelial cells. We speculate that the developing bile salt pool in the maturing intestine accounts for the increase in Fic1 protein expression in this tissue.


Asunto(s)
Adenosina Trifosfatasas/genética , Adenosina Trifosfatasas/metabolismo , Células Epiteliales/fisiología , Mucosa Intestinal/crecimiento & desarrollo , Mucosa Intestinal/fisiología , Animales , Conductos Biliares/citología , Conductos Biliares/crecimiento & desarrollo , Conductos Biliares/fisiología , Polaridad Celular/fisiología , Células Epiteliales/citología , Regulación del Desarrollo de la Expresión Génica , Humanos , Mucosa Intestinal/citología , Intestinos/crecimiento & desarrollo , Intestinos/fisiología , Hígado/crecimiento & desarrollo , Hígado/fisiología , Ratones , Ratones Endogámicos C57BL , Páncreas/crecimiento & desarrollo , Páncreas/fisiología , Proteínas de Transferencia de Fosfolípidos , Estómago/crecimiento & desarrollo , Estómago/fisiología
10.
Gastroenterology ; 127(2): 379-84, 2004 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-15300568

RESUMEN

BACKGROUND & AIMS: Progressive familial intrahepatic cholestasis (PFIC) and benign recurrent intrahepatic cholestasis (BRIC) are hereditary liver disorders; PFIC is characterized by severe progressive liver disease whereas BRIC patients have intermittent attacks of cholestasis without permanent liver damage. Mutations in ATP8B1 are present in PFIC type 1 and in a subset of BRIC patients. We hypothesized that a genetically distinct form of BRIC is associated with mutations in ABCB11. This gene encodes the bile salt export pump (BSEP) and is mutated in PFIC type 2. METHODS: Patients from 20 families were included; all had a normal ATP8B1 sequence. Sequencing of all 27 coding exons including the splice junctions of ABCB11 revealed 8 distinct mutations in 11 patients from 8 different families: one homozygous missense mutation (E297G) previously described in PFIC2 patients, 6 novel missense mutations, and one putative splice site mutation. RESULTS: In 12 families, no mutations in ATB8B1 or ABCB11 were detected. Pancreatitis is a known extrahepatic symptom in BRIC caused by ATP8B1 mutations, but was not present in BRIC patients with mutations in ABCB11. In contrast, cholelithiasis was observed in 7 of 11 BRIC patients with mutations in ABCB11, but has not been described in ATP8B1-affected BRIC patients. CONCLUSIONS: Mutations in ABCB11 are associated with BRIC, and consistent with the genetic classification of PFIC into 2 subtypes, we propose that this disorder be named BRIC type 2.


Asunto(s)
Transportadoras de Casetes de Unión a ATP/genética , Colestasis Intrahepática/genética , Mutación Missense , Miembro 11 de la Subfamilia B de Transportador de Casetes de Unión al ATP , Transportadoras de Casetes de Unión a ATP/química , Adolescente , Adulto , Empalme Alternativo , Colestasis Intrahepática/clasificación , Colestasis Intrahepática/fisiopatología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estructura Terciaria de Proteína , Recurrencia
11.
Kidney Int ; 66(3): 990-1000, 2004 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-15327392

RESUMEN

BACKGROUND: Hereditary tyrosinemia type 1 (HT1), which is associated with severe liver and kidney damage, is caused by deficiency of fumarylacetoacetate hydrolase (FAH), the last enzyme of the tyrosine breakdown cascade. HT1-associated liver and kidney failure can be prevented by blocking an enzyme upstream of FAH in the tyrosine breakdown pathway with 2-(2-nitro-4-trifluoromethylbenzoyl)-1,3-cyclohexanedione (NTBC). FAH knockout mice develop the HT1 phenotype when NTBC treatment is discontinued. METHODS: The occurrence of cell death was investigated in kidneys of Fah(-/-) mice on and off NTBC either unchallenged or injected with 800 mg/kg of homogentisic acid (HGA), an intermediate of tyrosine breakdown. RESULTS: No cell death could be detected in kidneys of Fah(-/-) mice on NTBC. A slight increase of cleaved caspase-3 was the only apoptosis-related feature that could be detected in kidneys of Fah(-/-) mice off NTBC. Challenge of Fah(-/-) mice on NTBC with HGA led to massive death of renal proximal tubular cells, with positive terminal deoxynucleotidyl transferase-mediated deoxyuridine diphosphate (dUDP) nick-end labeling (TUNEL) and DNA fragmentation assays, but hardly any cleavage of caspase-9 and caspase-3. Fah(-/-) mice off NTBC acquired resistance to HGA-induced renal cell death and the kidneys exhibited relatively few features of apoptosis upon challenge with HGA, with a small increase in expression of cleaved caspase-9 and caspase-3. CONCLUSION: Kidneys of adult Fah(-/-) mice, withdrawn from NTBC for 15 days, reveal limited characteristics of apoptosis, and have acquired resistance to a caspase-9- and caspase-3-independent form of cell death provoked by HGA.


Asunto(s)
Fragmentación del ADN/fisiología , Hidrolasas/genética , Túbulos Renales Proximales/patología , Tirosinemias/patología , Animales , Caspasa 3 , Caspasa 9 , Caspasas/metabolismo , Ciclohexanonas/farmacología , Modelos Animales de Enfermedad , Inhibidores Enzimáticos/farmacología , Hepatocitos/trasplante , Ácido Homogentísico/farmacología , Etiquetado Corte-Fin in Situ , Ratones , Ratones Noqueados , Nitrobenzoatos/farmacología , Tasa de Supervivencia , Tirosina/metabolismo , Tirosinemias/genética , Tirosinemias/mortalidad
12.
Hepatology ; 39(2): 433-43, 2004 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-14767996

RESUMEN

The murine model of hereditary tyrosinemia type 1 (HT1) was used to analyze the relationship between chronic liver disease and programmed cell death in vivo. In healthy fumarylacetoacetate hydrolase deficient mice (Fah(-/-)), protected from liver injury by the drug 2-(2- nitro-4-trifluoromethylbenzoyl)-1,3-cyclohexanedione (NTBC), the tyrosine metabolite homogentisic acid (HGA) caused rapid hepatocyte death. In contrast, all mice survived the same otherwise lethal dose of HGA if they had preexisting liver damage induced by NTBC withdrawal. Similarly, Fah(-/-) animals with liver injury were also resistant to apoptosis induced by the Fas ligand Jo-2 and to necrosis-like cell death induced by acetaminophen (APAP). Molecular studies revealed a marked up-regulation of the antiapoptotic heat shock proteins (Hsp) 27, 32, and 70 and of c-Jun in hepatocytes of stressed mice. In addition, the p38 and Jun N-terminal kinase (JNK) stress-activated kinase pathways were markedly impaired in the cell-death resistant liver. In conclusion, these results provide evidence that chronic liver disease can paradoxically result in cell death resistance in vivo. Stress-induced failure of cell death programs may lead to an accumulation of damaged cells and therefore enhance the risk for cancer as observed in HT1 and other chronic liver diseases.


Asunto(s)
Hidrolasas/genética , Fallo Hepático Agudo/metabolismo , Tirosinemias/metabolismo , Tirosinemias/patología , Acetaminofén , Analgésicos no Narcóticos , Animales , Apoptosis/efectos de los fármacos , Apoptosis/fisiología , Supervivencia Celular/fisiología , Depresores del Sistema Nervioso Central/farmacología , Enfermedad Crónica , Ciclohexanonas/farmacología , Inhibidores Enzimáticos/farmacología , Etanol/farmacología , Proteína Ligando Fas , Glutatión/metabolismo , Proteínas HSP70 de Choque Térmico/metabolismo , Ácido Homogentísico/metabolismo , Fallo Hepático Agudo/inducido químicamente , Fallo Hepático Agudo/patología , Glicoproteínas de Membrana/farmacología , Ratones , Ratones Mutantes , FN-kappa B/metabolismo , Necrosis , Nitrobenzoatos/farmacología , Estrés Oxidativo/fisiología , Proteínas Proto-Oncogénicas c-jun/metabolismo , Regulación hacia Arriba , Receptor fas/metabolismo
13.
J Hepatol ; 39(6): 901-9, 2003 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-14642604

RESUMEN

BACKGROUND: Hereditary Tyrosinemia type I, caused by deficiency of fumarylacetoacetate hydrolase (FAH), is characterized by liver and kidney damage. Administration of 2-(2-nitro-4-trifluoromethylbenzoyl)-1,3-cyclohexanedione (NTBC) corrects the tyrosinemia phenotype, but does not prevent development of hepatocellular carcinoma. AIM: To gain insight into the pathophysiological changes associated with liver damage induced by tyrosinemia and the preventive action of NTBC on these changes. METHODS: Differential gene expression patterns in livers of tyrosinemia-affected and healthy mice, and of tyrosinemia-affected and NTBC-treated Fah-/- mice were investigated by suppression subtractive hybridization. RESULTS: Transcripts encoding proteins playing a role in protein turnover, growth and proliferation, RNA processing, and signal transduction were primarily induced in tyrosinemia-affected livers. Transcripts mainly contributing to the profile of suppressed genes encode proteins that are secreted by the liver, or are necessary for intermediate metabolism. NTBC treatment fails to normalize the tyrosinemia-induced alterations in expression of transcripts encoding proteins involved in protein turnover, signal transduction, and cell growth and proliferation. CONCLUSIONS: The failure of NTBC to normalize liver gene expression of Fah-/- mice may play a role in rendering the tyrosinemia-affected liver susceptible to development of hepatocellular carcinoma under NTBC treatment.


Asunto(s)
Ciclohexanonas/farmacología , Inhibidores Enzimáticos/farmacología , Hígado/fisiología , Nitrobenzoatos/farmacología , Tirosinemias/tratamiento farmacológico , Tirosinemias/genética , Animales , Northern Blotting , ADN Complementario , Femenino , Expresión Génica/efectos de los fármacos , Perfilación de la Expresión Génica , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Mutantes , Fenotipo , Reproducibilidad de los Resultados , Tirosinemias/fisiopatología
14.
Biochem J ; 370(Pt 3): 881-9, 2003 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-12466020

RESUMEN

We have used indirect immunofluorescense studies and glycosylation-site insertion and deletion mapping to characterize the topology of human copper transporter 1 (hCTR1), the putative human high-affinity copper-import protein. Both approaches indicated that hCTR1 contains three transmembrane domains and that the N-terminus of hCTR1, which contains several putative copper-binding sites, is localized extracellularly, whereas the C-terminus is exposed to the cytosol. Based on previous observations that CTR1 proteins form high-molecular-mass complexes, we investigated directly whether CTR1 proteins interact with themselves. Yeast two-hybrid studies showed that interaction of yeast, mouse, rat and human CTR1 occurs at the sites of their N-terminal domains, and is not dependent on the copper concentration in the growth media. Analysis of deletion constructs indicated that multiple regions in the N-terminus are essential for this self-interaction. In contrast, the N-terminal tail of the presumed low-affinity copper transporter, hCTR2, does not interact with itself. Taken together, these results suggest that CTR1 spans the membrane at least six times, permitting formation of a channel, which is consistent with its proposed role as a copper transporter.


Asunto(s)
Proteínas de Transporte de Catión , Proteínas de la Membrana/química , Proteínas de la Membrana/metabolismo , Conformación Proteica , Secuencia de Aminoácidos , Animales , Línea Celular , Cobre/metabolismo , Transportador de Cobre 1 , Proteínas Fúngicas/química , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Glicosilación , Humanos , Proteínas de la Membrana/genética , Microscopía Fluorescente , Modelos Moleculares , Datos de Secuencia Molecular , Mutación , Unión Proteica , Técnicas del Sistema de Dos Híbridos
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