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1.
BMC Health Serv Res ; 17(1): 234, 2017 03 24.
Artículo en Inglés | MEDLINE | ID: mdl-28340614

RESUMEN

BACKGROUND: Family-focused practice (FFP) is an effective approach to supporting individuals with mental illness. 'Recovery' is also central to contemporary mental health care. However, there is a dearth of evidence about how the two concepts are related and subsequently implemented in practice. The aim of this study was to explore practitioners' understandings and practices of FFP within a recovery framework. METHODS: Purposive/snowball sampling was used to recruit and conduct qualitative interviews with 11 mental health practitioners in rural Australia. Concurrent sampling and data collection were informed by thematic analysis and continued until data saturation was reached. RESULTS: Participants found it difficult to articulate their understandings of FFP within a recovery framework. Nonetheless they were able to describe practices that embodied family-focused recovery. Barriers to such practices included medical models of care, where there are often a shortage of skilled staff and high demands for care. Stigma (self and from others) and confidentiality were also identified as barriers to involving family members in recovery focused care. CONCLUSIONS: Family-focused recovery care is a priority in many high-income countries. A family-focused recovery framework is needed to assist service planners, practitioners, family members and those with mental health needs and ensure such care is embedded within practice guidelines.


Asunto(s)
Conocimientos, Actitudes y Práctica en Salud , Trastornos Mentales/rehabilitación , Adulto , Actitud del Personal de Salud , Salud de la Familia , Medicina Familiar y Comunitaria , Femenino , Accesibilidad a los Servicios de Salud , Humanos , Masculino , Persona de Mediana Edad , Nueva Gales del Sur , Investigación Cualitativa , Salud Rural , Estigma Social , Apoyo Social , Victoria , Adulto Joven
2.
Am J Transplant ; 16(3): 877-85, 2016 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-26474298

RESUMEN

From 5000 to 10 000 kidney patients die prematurely in the United States each year, and about 100 000 more suffer the debilitating effects of dialysis, because of a shortage of transplant kidneys. To reduce this shortage, many advocate having the government compensate kidney donors. This paper presents a comprehensive cost-benefit analysis of such a change. It considers not only the substantial savings to society because kidney recipients would no longer need expensive dialysis treatments--$1.45 million per kidney recipient--but also estimates the monetary value of the longer and healthier lives that kidney recipients enjoy--about $1.3 million per recipient. These numbers dwarf the proposed $45 000-per-kidney compensation that might be needed to end the kidney shortage and eliminate the kidney transplant waiting list. From the viewpoint of society, the net benefit from saving thousands of lives each year and reducing the suffering of 100 000 more receiving dialysis would be about $46 billion per year, with the benefits exceeding the costs by a factor of 3. In addition, it would save taxpayers about $12 billion each year.


Asunto(s)
Compensación y Reparación , Organización de la Financiación/legislación & jurisprudencia , Política de Salud/economía , Fallo Renal Crónico/cirugía , Trasplante de Riñón/economía , Donadores Vivos/legislación & jurisprudencia , Obtención de Tejidos y Órganos/economía , Análisis Costo-Beneficio , Femenino , Organización de la Financiación/organización & administración , Estudios de Seguimiento , Regulación Gubernamental , Costos de la Atención en Salud , Necesidades y Demandas de Servicios de Salud/economía , Necesidades y Demandas de Servicios de Salud/legislación & jurisprudencia , Humanos , Trasplante de Riñón/legislación & jurisprudencia , Donadores Vivos/provisión & distribución , Masculino , Persona de Mediana Edad , Obtención de Tejidos y Órganos/legislación & jurisprudencia , Obtención de Tejidos y Órganos/organización & administración , Estados Unidos
3.
Nat Rev Cancer ; 1(2): 130-41, 2001 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-11905804

RESUMEN

Direct targeting of cancer cells with gene therapy has the potential to treat cancer on the basis of its molecular characteristics. But although laboratory results have been extremely encouraging, many practical obstacles need to be overcome before gene therapy can fulfil its goals in the clinic. These issues are not trivial, but seem less formidable than the challenge of killing cancers selectively and rationally--a challenge that has been successfully addressed.


Asunto(s)
Terapia Genética , Neoplasias/terapia , Animales , Apoptosis/genética , Biotransformación/genética , Efecto Espectador , Ensayos Clínicos Fase I como Asunto , Ensayos Clínicos Fase II como Asunto , Virus Defectuosos/genética , Inhibidores Enzimáticos/farmacología , Inhibidores Enzimáticos/uso terapéutico , Enzimas/genética , Enzimas/metabolismo , Femenino , Predicción , Regulación Neoplásica de la Expresión Génica/genética , Genes BRCA1 , Genes Supresores de Tumor , Genes p53 , Terapia Genética/tendencias , Vectores Genéticos/genética , Vectores Genéticos/inmunología , Vectores Genéticos/fisiología , Vectores Genéticos/uso terapéutico , Herpesviridae/genética , Herpesviridae/inmunología , Herpesviridae/fisiología , Humanos , Mastadenovirus/genética , Mastadenovirus/fisiología , Ratones , Ratones Noqueados , Ratones Transgénicos , Neoplasias/genética , Neoplasias Experimentales/genética , Neoplasias Experimentales/terapia , Oncogenes , Neoplasias Ováricas/genética , Neoplasias Ováricas/terapia , Profármacos/farmacocinética , Profármacos/uso terapéutico , Replicación Viral
4.
Nat Genet ; 5(3): 242-7, 1993 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-8275088

RESUMEN

GTPase Activating Protein (GAP) is involved in down-regulating normal ras proteins and in the signal transduction pathway of some growth factors. We have screened 188 human tumours for mutations in the catalytic domain and at the C terminal SH2 region GAP. Three nonsense mutations in basal cell carcinomas were detected in the SH2 region and no mutations could be demonstrated in the catalytic domain. We conclude that mutations in the SH2 region of GAP may play a role in tumorigenesis and that inactivating mutations of the GAP catalytic domain do not contribute to tumour development.


Asunto(s)
Mutación , Neoplasias/genética , Proteínas/genética , Secuencia de Aminoácidos , Secuencia de Bases , Sitios de Unión , Catálisis , Cartilla de ADN , ADN de Neoplasias , Proteínas Activadoras de GTPasa , Humanos , Datos de Secuencia Molecular , Reacción en Cadena de la Polimerasa , Proteínas/metabolismo , Proteínas Activadoras de ras GTPasa
5.
Nat Genet ; 12(2): 144-8, 1996 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-8563751

RESUMEN

Individuals with neurofibromatosis type 1 (NF1) are predisposed to certain cancers including juvenile chronic myelogenous leukaemia (JCML). The NF1 tumour-suppressor gene encodes a protein (neurofibromin) that accelerates GTP hydrolysis on Ras proteins. Here we show that primary leukaemic cells from children with NF1 show a selective decrease in NF1-like GTPase activating protein (GAP) activity for Ras but retain normal cellular GAP activity. Leukaemic cells also show an elevated percentage of Ras in the GTP-bound conformation. JCML cells are hypersensitive to granulocyte-macrophage colony stimulating factor (GM-CSF), and we observed a similar pattern of aberrant growth in haematopoietic cells from Nf1-/- mouse embryos. These data define a specific role for neurofibromin in negatively regulating GM-CSF signaling through Ras in haematopoietic cells and they suggest that hypersensitivity to GM-CSF may be a primary event in the development of JCML.


Asunto(s)
Células Madre Hematopoyéticas/patología , Neurofibromatosis 1/metabolismo , Proteínas/fisiología , Proteínas ras/fisiología , Animales , División Celular , Células Cultivadas , Niño , Proteínas Activadoras de GTPasa , Genes de Neurofibromatosis 1 , Factor Estimulante de Colonias de Granulocitos y Macrófagos/farmacología , Guanosina Trifosfato/metabolismo , Humanos , Leucemia Mielógena Crónica BCR-ABL Positiva/patología , Ratones , Neurofibromatosis 1/patología , Neurofibromina 1 , Proteínas/metabolismo , Transducción de Señal/fisiología , Proteínas Activadoras de ras GTPasa , Proteínas ras/metabolismo
7.
Nat Med ; 3(6): 639-45, 1997 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-9176490

RESUMEN

The 55-kilodalton (kDa) protein from the E1B-region of adenovirus binds to and inactivates the p53 gene, which is mutated in half of human cancers. We have previously shown that the replication and cytopathogenicity of an E1B, 55-kDa gene-attenuated adenovirus, ONYX-015, is blocked by functional p53 in RKO and U20S carcinoma lines. We now report that normal human cells were highly resistant to ONYX-015-mediated, replication-dependent cytolysis. In contrast, a wide range of human tumor cells, including numerous carcinoma lines with either mutant or normal p53 gene sequences (exons 5-9), were efficiently destroyed. Antitumoral efficacy was documented following intratumoral or intravenous administration of ONYX-015 to nude mouse-human tumor xenografts; efficacy with ONYX-015 plus chemotherapy (cisplatin, 5-fluorouracil) was significantly greater than with either agent alone.


Asunto(s)
Proteínas E1B de Adenovirus/genética , Proteínas de la Cápside , Endotelio Vascular/virología , Neoplasias Experimentales/terapia , Adenoviridae/genética , Antígenos Virales/metabolismo , Cápside/metabolismo , Células Cultivadas , Quimioterapia Adyuvante/métodos , Cisplatino/administración & dosificación , Epitelio/virología , Femenino , Fluorouracilo/administración & dosificación , Glioblastoma/patología , Glioblastoma/terapia , Humanos , Inyecciones Intralesiones , Neoplasias Laríngeas/patología , Neoplasias Laríngeas/terapia , Trasplante de Neoplasias , Células Tumorales Cultivadas , Proteína p53 Supresora de Tumor/deficiencia , Proteína p53 Supresora de Tumor/fisiología , Neoplasias del Cuello Uterino/metabolismo , Neoplasias del Cuello Uterino/patología , Neoplasias del Cuello Uterino/terapia
8.
Nat Med ; 6(10): 1128-33, 2000 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-11017144

RESUMEN

The adenovirus mutant dl1520 (ONYX-015) does not express the E1B-55K protein that binds and inactivates p53. This virus replicates in tumor cells with mutant p53, but not in normal cells with functional p53. Although intra-tumoral injection of dl1520 shows promising responses in patients with solid tumors, previous in vitro studies have not established a close correlation between p53 status and dl1520 replication. Here we identify loss of p14ARF as a mechanism that allows dl1520 replication in tumor cells retaining wild-type p53. We demonstrate that the re-introduction of p14ARF into tumor cells with wild-type p53 suppresses replication of dl1520 in a p53-dependent manner. Our study supports the therapeutic use of dl1520 in tumors with lesions within the p53 pathway other than mutation of p53.


Asunto(s)
Adenoviridae/genética , Mutación , Proteínas Nucleares , Proteínas/genética , Replicación Viral , Regulación Neoplásica de la Expresión Génica , Humanos , Proteínas/metabolismo , Proteínas Proto-Oncogénicas/genética , Proteínas Proto-Oncogénicas/metabolismo , Proteínas Proto-Oncogénicas c-mdm2 , Células Tumorales Cultivadas/virología , Proteína p14ARF Supresora de Tumor , Proteína p53 Supresora de Tumor/genética , Proteína p53 Supresora de Tumor/metabolismo
9.
Sci Rep ; 11(1): 11807, 2021 06 03.
Artículo en Inglés | MEDLINE | ID: mdl-34083588

RESUMEN

Direct evidence of ancient human occupation is typically established through archaeological excavation. Excavations are costly and destructive, and practically impossible in some lake and wetland environments. We present here an alternative approach, providing direct evidence from lake sediments using DNA metabarcoding, steroid lipid biomarkers (bile acids) and from traditional environmental analyses. Applied to an early Medieval Celtic settlement in Ireland (a crannog) this approach provides a site chronology and direct evidence of human occupation, crops, animal farming and on-site slaughtering. This is the first independently-dated, continuous molecular archive of human activity from an archeological site, demonstrating a link between animal husbandry, food resources, island use. These sites are under threat but are impossible to preserve in-situ so this approach can be used, with or without excavation, to produce a robust and full site chronology and provide direct evidence of occupation, the use of plants and animals, and activities such as butchery.


Asunto(s)
Arqueología , Biomarcadores , ADN Antiguo , Lagos , Lípidos , Animales , Arqueología/métodos , Historia Medieval , Humanos , Irlanda , Minerales/análisis , Datación Radiométrica , Reino Unido
10.
Gene Ther ; 17(12): 1517-24, 2010 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-20686507

RESUMEN

Oncolytic adenoviruses are being investigated as potential anti-cancer agents. Selective lytic replication in cancer cells is essential for an effective and safe treatment. In this study, we compared 11 oncolytic adenoviruses in relevant cell cultures to assess their use for treating oral cancer and pre-cancerous lesions. We determined the cytotoxicity of oncolytic adenovirus infection and calculated selectivity indices for cytotoxicity to cancer cells compared with normal oral keratinocytes and fibroblasts. Keratinocytes were very sensitive to wild-type adenovirus serotype 5 (Ad5); 1- to 3-log more than head and neck squamous cell carcinoma (HNSCC) cells. The potencies of oncolytic adenoviruses to kill HNSCC cells within 7 days after infection ranged from approximately 10 times less potent to approximately 10 times more potent than Ad5. The selectivity indices determined on fibroblasts and keratinocytes differed markedly. Two oncolytic adenoviruses were more selective than Ad5 for HNSCC cells compared with fibroblasts; and five viruses showed selective replication on HNSCC cells compared with keratinocytes. Overall, CRAd-S.RGD with E1A driven by the survivin promoter and an infectivity-enhancing capsid modification showed the most favourable cytotoxicity pattern; being very potent in killing HNSCC cells, only slightly less effective than Ad5 in killing pre-neoplastic keratinocytes and the least toxic to normal keratinocytes.


Asunto(s)
Adenoviridae/genética , Adenoviridae/metabolismo , Vectores Genéticos , Neoplasias de la Boca/terapia , Viroterapia Oncolítica , Virus Oncolíticos/genética , Lesiones Precancerosas/terapia , Carcinoma de Células Escamosas/terapia , Línea Celular Tumoral , Supervivencia Celular , Vectores Genéticos/genética , Vectores Genéticos/metabolismo , Humanos , Proteínas Inhibidoras de la Apoptosis/genética , Neoplasias de la Boca/patología , Virus Oncolíticos/metabolismo , Regiones Promotoras Genéticas/genética , Survivin
11.
Child Care Health Dev ; 36(2): 165-78, 2010 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-19886907

RESUMEN

BACKGROUND: Breastfeeding/breastmilk feeding of infants in neonatal units is vital to the preservation of short- and long-term health, but rates are very low in many neonatal units internationally. The aim of this review was to evaluate the effectiveness of clinical, public health and health promotion interventions that may promote or inhibit breastfeeding/breastmilk feeding for infants admitted to neonatal units. METHODS: Systematic review with narrative synthesis. Studies were identified from structured searches of 19 electronic databases from inception to February 2008; hand searching of bibliographies; Advisory Group members helped identify additional sources. INCLUSION CRITERIA: controlled studies of interventions intended to increase breastfeeding/feeding with breastmilk that reported breastmilk feeding outcomes and included infants admitted to neonatal units, their mothers, families and caregivers. Data were extracted and appraised for quality using standard processes. Study selection, data extraction and quality assessment were independently checked. Study heterogeneity prevented meta-analysis. RESULTS: Forty-eight studies were identified, mainly measuring short-term outcomes of single interventions in stable infants. We report here a sub-set of 21 studies addressing interventions tested in at least one good-quality or more than one moderate-quality study. Effective interventions identified included kangaroo skin-to-skin contact, simultaneous milk expression, peer support in hospital and community, multidisciplinary staff training, and Unicef Baby Friendly accreditation of the associated maternity hospital. CONCLUSIONS: Breastfeeding/breastmilk feeding is promoted by close, continuing skin-to-skin contact between mother and infant, effective breastmilk expression, peer support in hospital and community, and staff training. Evidence gaps include health outcomes and costs of intervening with less clinically stable infants, and maternal health and well-being. Effects of public health and policy interventions and the organization of neonatal services remain unclear. Infant feeding in neonatal units should be included in public health surveillance and policy development; relevant definitions are proposed.


Asunto(s)
Lactancia Materna/estadística & datos numéricos , Educación en Salud/organización & administración , Promoción de la Salud/métodos , Promoción de la Salud/normas , Femenino , Humanos , Recién Nacido , Relaciones Madre-Hijo , Salud Pública , Reino Unido
12.
Trends Cell Biol ; 4(10): 347-50, 1994 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-14731620

RESUMEN

Ras proteins regulate cell growth and differentiation, and their mutation plays a major, direct role in causing human cancer. For years, their precise function has been a mystery. One of the pathways Ras controls has recently been identified. It consists of a cascade of kinases (Raf, MEK and MAP kinases) that transmits signals from the plasma membrane to the nucleus. The role of Ras is remarkably simple: it recruits Raf from the cytoplasm to the plasma membrane. Once in the membrane, Raf is activated and the kinase cascade is initiated. Is this the whole story?

13.
Trends Cell Biol ; 9(12): M53-6, 1999 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-10611683

RESUMEN

Cancer is caused by the stepwise accumulation of mutations that affect growth control, differentiation and survival. The view that mutations affect discrete signalling pathways, each contributing to a specific aspect of the full malignant phenotype, has proved to be too simplistic. We now know that oncogenes and tumour suppressors depend on one another for their selective advantage, and that they affect multiple pathways that intersect and overlap. The interactive nature of each genetic change has important implications for cancer therapy and for the stepwise model of carcinogenesis.


Asunto(s)
Proteínas del Citoesqueleto/fisiología , Neoplasias/etiología , Transducción de Señal/fisiología , Proteínas ras/fisiología , Proteína de la Poliposis Adenomatosa del Colon , Animales , Humanos
14.
J Cell Biol ; 106(5): 1649-58, 1988 May.
Artículo en Inglés | MEDLINE | ID: mdl-3286660

RESUMEN

The cellular localization of phospholipase A2 (PLA2) was examined in normal and ras-transformed rat fibroblasts using immunohistochemical techniques. Polyclonal antibodies were generated against porcine pancreatic PLA2 and were affinity purified for use in this study. The antibodies detected a 16-kD band on immunoblots of total cellular proteins from fibroblasts. In cell-free assays of phospholipase A2 activity, the purified antibodies inhibited the bulk of the enzyme activity whereas control IgG preparations had no effect. Immunofluorescence microscopy indicated that PLA2 was diffusely distributed throughout the cell. Increased concentration of PLA2 was detected under membrane ruffles in normal and ras-transformed cells. Specific immunofluorescence staining was also detected on the outer surface of the normal cells. Immunoelectron microscopy demonstrated the increased accumulation of PLA2 in membrane ruffles and also revealed the presence of the enzyme in microvilli and its association with intracellular vesicles. Ultrastructural localization of PLA2 and the ras oncogene protein, using a double immunogold labeling technique, indicated a spatial proximity between PLA2 and ras proteins in the ruffles of ras-transformed cells. The possible role of PLA2 in the structural rearrangements that underlie membrane ruffling is discussed.


Asunto(s)
Membrana Celular/enzimología , Citoplasma/enzimología , Membranas Intracelulares/enzimología , Fosfolipasas A/análisis , Fosfolipasas/análisis , Proteínas Proto-Oncogénicas/análisis , Animales , Anticuerpos/inmunología , Anticuerpos/aislamiento & purificación , Línea Celular , Línea Celular Transformada , Membrana Celular/análisis , Cromatografía de Afinidad , Fibroblastos , Técnica del Anticuerpo Fluorescente , Inmunohistoquímica , Membranas Intracelulares/análisis , Proteínas de la Membrana/análisis , Microscopía Electrónica , Microscopía Electrónica de Rastreo , Microvellosidades/análisis , Microvellosidades/enzimología , Fosfolipasas A/inmunología , Fosfolipasas A2 , Proteínas Proto-Oncogénicas p21(ras) , Ratas
15.
Science ; 238(4826): 542-5, 1987 Oct 23.
Artículo en Inglés | MEDLINE | ID: mdl-2821624

RESUMEN

The role of guanine nucleotides in ras p21 function was determined by using the ability of p21 protein to induce maturation of Xenopus oocytes as a quantitative assay for biological activity. Two oncogenic mutant human N-ras p21 proteins, Asp12 and Val12, actively induced maturation, whereas normal Gly12 p21 was relatively inactive in this assay. Both mutant proteins were found to be associated with guanosine triphosphate (GTP) in vivo. In contrast, Gly12 p21 was predominantly guanosine diphosphate (GDP)-bound because of a dramatic stimulation of Gly12 p21-associated guanosine triphosphatase (GTPase) activity. A cytoplasmic protein was shown to be responsible for this increase in activity. This protein stimulated GTP hydrolysis by purified Gly12 p21 more than 200-fold in vitro, but had no effect on Asp12 or Val12 mutants. A similar factor could be detected in extracts from mammalian cells. It thus appears that, in Xenopus oocytes, this protein maintains normal p21 in a biologically inactive, GDP-bound state through its effect on GTPase activity. Furthermore, it appears that the major effect of position 12 mutations is to prevent this protein from stimulating p21 GTPase activity, thereby allowing these mutants to remain in the active GTP-bound state.


Asunto(s)
Citoplasma/análisis , GTP Fosfohidrolasas/metabolismo , Nucleótidos de Guanina/fisiología , Monoéster Fosfórico Hidrolasas/metabolismo , Proteínas/farmacología , Proteínas Proto-Oncogénicas/fisiología , Animales , Bioensayo , Femenino , Guanosina Difosfato/metabolismo , Guanosina Trifosfato/metabolismo , Guanilil Imidodifosfato/metabolismo , Hidrólisis , Técnicas de Inmunoadsorción , Mutación , Oocitos/efectos de los fármacos , Oocitos/crecimiento & desarrollo , Proteínas Proto-Oncogénicas/metabolismo , Proteínas Proto-Oncogénicas/farmacología , Proteínas Proto-Oncogénicas p21(ras) , Relación Estructura-Actividad , Xenopus laevis
16.
Science ; 262(5136): 1069-72, 1993 Nov 12.
Artículo en Inglés | MEDLINE | ID: mdl-7694367

RESUMEN

Activation of the Raf and extracellular signal-regulated kinases (ERKs) (or mitogen-activated protein kinases) are key events in mitogenic signalling, but little is known about interactions with other signaling pathways. Agents that raise levels of intracellular cyclic adenosine 3',5'-monophosphate (cAMP) blocked DNA synthesis and signal transduction in Rat1 cells exposed to epidermal growth factor (EGF) or lysophosphatidic acid. In the case of EGF, receptor tyrosine kinase activity and association with the signaling molecules Grb2 and Shc were unaffected by cAMP. Likewise, EGF-dependent accumulation of the guanosine 5'-triphosphate-bound form of Ras was unaffected. In contrast, activation of Raf-1 and ERK kinases was inhibited. Thus, cAMP appears to inhibit signal transmission from Ras by preventing Ras-dependent activation of Raf-1.


Asunto(s)
Proteínas Quinasas Dependientes de Calcio-Calmodulina/metabolismo , AMP Cíclico/farmacología , Proteínas Quinasas Activadas por Mitógenos , Proteínas Tirosina Quinasas/metabolismo , Proteínas Proto-Oncogénicas p21(ras)/metabolismo , Proteínas Proto-Oncogénicas/metabolismo , Transducción de Señal , 1-Metil-3-Isobutilxantina/farmacología , Animales , Bucladesina/farmacología , Línea Celular , Toxina del Cólera/farmacología , Proteínas Quinasas Dependientes de AMP Cíclico/metabolismo , Activación Enzimática , Factor de Crecimiento Epidérmico/farmacología , Receptores ErbB/metabolismo , Interfase , Lisofosfolípidos/farmacología , Proteína Quinasa 1 Activada por Mitógenos , Proteína Quinasa 3 Activada por Mitógenos , Fosforilación , Proteínas Proto-Oncogénicas c-raf , Ratas
17.
Science ; 252(5005): 576-9, 1991 Apr 26.
Artículo en Inglés | MEDLINE | ID: mdl-1902323

RESUMEN

Ras-GAP (GTPase activating protein) is a regulatory protein that stimulates the intrinsic guanosine triphosphatase (GTPase) activity of the proto-oncogene product p21ras. A domain of the neurofibromatosis gene product (NF1) that has sequence similarity to the catalytic domain of Ras-GAP and to yeast IRA gene products also has a specific stimulatory activity toward p21ras GTPase. Arachidonic acid and phosphatidic acid inactivate GAP, but no agents have been identified that stimulate GAP and thereby switch p21ras off. With the use of recombinant Ha-c-Ras and Ras-GAP, NF1, and GAP catalytic domains, it was found that prostaglandins PGF2 alpha and PGA2 stimulated Ras-GAP and that prostacyclin PGI2 inhibited Ras-GAP. The stimulatory effect of PGF2 alpha was saturable and structure-specific and competed with the inhibitory effect of arachidonic acid. Arachidonic acid also inhibited the catalytic activity of NF1, but prostaglandins were not stimulatory. These results suggest a mechanism for the allosteric control of Ras function through the modulation of arachidonate metabolism.


Asunto(s)
Genes ras/efectos de los fármacos , Prostaglandinas/farmacología , Proteínas/genética , Ácido Araquidónico , Ácidos Araquidónicos/farmacología , Dinoprost/farmacología , GTP Fosfohidrolasas/metabolismo , Proteínas Activadoras de GTPasa , Regulación de la Expresión Génica/efectos de los fármacos , Guanosina Trifosfato/metabolismo , Humanos , Cinética , Neurofibromatosis 1/genética , Neurofibromina 1 , Proto-Oncogenes Mas , Proteínas Proto-Oncogénicas p21(ras)/metabolismo , Proteínas Recombinantes/metabolismo , Proteínas Activadoras de ras GTPasa
18.
Science ; 265(5179): 1713-6, 1994 Sep 16.
Artículo en Inglés | MEDLINE | ID: mdl-8085158

RESUMEN

To identify proteins that may participate in the activation of the protein kinase Raf, proteins that interact with Raf were selected in a two-hybrid screen. Two members of the 14-3-3 protein family were isolated that interacted with both the amino terminal regulatory regions of Raf and the kinase domain of Raf, but did not compete with the guanine nucleotide-binding protein Ras for binding to Raf. 14-3-3 proteins associated with Raf in mammalian cells and accompanied Raf to the membrane in the presence of activated Ras. In yeast cells expressing Raf and MEK, mammalian 14-3-3 beta or 14-3-3 zeta activated Raf to a similar extent as did expression of Ras. Therefore, 14-3-3 proteins may participate in or be required for the regulation of Raf function. These findings suggest a role for 14-3-3 proteins in Raf-mediated signal transduction.


Asunto(s)
Quinasas de Proteína Quinasa Activadas por Mitógenos , Proteínas del Tejido Nervioso/metabolismo , Proteínas Serina-Treonina Quinasas/metabolismo , Proteínas Proto-Oncogénicas/metabolismo , Tirosina 3-Monooxigenasa , Proteínas 14-3-3 , Secuencia de Aminoácidos , Animales , Línea Celular , Membrana Celular/enzimología , Citosol/enzimología , Activación Enzimática , Proteínas de Unión al GTP/metabolismo , Células HeLa , Humanos , MAP Quinasa Quinasa 1 , Datos de Secuencia Molecular , Proteínas Serina-Treonina Quinasas/química , Proteínas Serina-Treonina Quinasas/genética , Proteínas Tirosina Quinasas/genética , Proteínas Tirosina Quinasas/metabolismo , Proteínas Proto-Oncogénicas/química , Proteínas Proto-Oncogénicas c-raf , Proteínas Recombinantes/metabolismo , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/crecimiento & desarrollo , Transducción de Señal , Dedos de Zinc
19.
Science ; 236(4803): 840-3, 1987 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-3554510

RESUMEN

The oncogene protein product (p21) of the ras gene has been implicated in mediating the effects of a variety of growth factors and hormones. Microinjection of monoclonal antibody 6B7, which is directed against a synthetic peptide corresponding to a highly conserved region of p21 (amino acids 29 to 44) required for p21 function, specifically inhibited Xenopus oocyte maturation induced by incubation with insulin. The inhibition was dose-dependent and specific since (i) the same antibody had no effect on progesterone-induced maturation, (ii) immunoprecipitation and Western blotting indicated that the antibody recognized a single protein of molecular weight 21,000 in oocyte extracts, and (iii) inhibition was not observed with identical concentrations of normal immunoglobulin. Thus, p21 appears to be involved in mediating insulin-induced maturation of Xenopus oocytes. Furthermore, the mechanism may involve phosphorylation of p21, as p21 was found to be a substrate of the insulin receptor kinase.


Asunto(s)
Insulina/farmacología , Oncogenes , Oocitos/citología , Proteínas Proto-Oncogénicas/fisiología , Animales , Anticuerpos , Femenino , Inmunoglobulina G , Oocitos/efectos de los fármacos , Progesterona/farmacología , Proteínas Proto-Oncogénicas/genética , Xenopus laevis
20.
Science ; 240(4851): 518-21, 1988 Apr 22.
Artículo en Inglés | MEDLINE | ID: mdl-2833817

RESUMEN

A cytoplasmic protein that greatly enhances the guanosine triphosphatase (GTPase) activity of N-ras protein but does not affect the activity of oncogenic ras mutants has been recently described. This protein (GAP) is shown here to be ubiquitous in higher eukaryotes and to interact with H-ras as well as with N-ras proteins. To identify the region of ras p21 with which GAP interacts, 21 H-ras mutant proteins were purified and tested for their ability to undergo stimulation of GTPase activity by GAP. Mutations in nonessential regions of H-ras p21 as well as mutations in its carboxyl-terminal domain (residues 165-185) and purine binding region (residues 117 and 119) did not decrease the ability of the protein to respond to GAP. In addition, an antibody against the carboxyl-terminal domain did not block GAP activity, supporting the conclusion that GAP does not interact with this region. Transforming mutations at positions 12, 59, and 61 (the phosphoryl binding region) abolished GTPase stimulation by GAP. Point mutations in the putative effector region of ras p21 (amino acids 35, 36, and 38) were also insensitive to GAP. However, a point mutation at position 39, shown previously not to impair effector function, did not alter GAP-p21 interaction. These results indicate that GAP interaction may be essential for ras p21 biological activity and that it may be a ras effector protein.


Asunto(s)
GTP Fosfohidrolasas/metabolismo , Proteínas de Unión al GTP/metabolismo , Genes ras , Monoéster Fosfórico Hidrolasas/metabolismo , Proteínas/metabolismo , Proteínas Proto-Oncogénicas/metabolismo , Secuencia de Aminoácidos , Animales , Anticuerpos Monoclonales/inmunología , Análisis Mutacional de ADN , Activación Enzimática , Proteínas Activadoras de GTPasa , Técnicas Inmunológicas , Técnicas In Vitro , Relación Estructura-Actividad , Proteínas Activadoras de ras GTPasa
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