Base de dados : LILACS
Pesquisa : D12.776.543.750.695.955 [Categoria DeCS]
Referências encontradas : 9 [refinar]
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Id: lil-560451
Autor: Oliveira, Laerte.
Título: Family A G-Protein coupled receptors: an overview of structure-function relationships
Fonte: ARBS annu. rev. biomed. sci;11(n.esp):T51-T85, 20090000. ilus.
Idioma: en.
Resumo: Family A G-protein coupled receptors (AGPCRs) form the largest group of correlate receptors whose structure, a bundle of seven-trans-membrane (7 TM) helices, may be activated thus becoming able to transduce a signal from the extracellular medium to the cytosol. This activation may be constitutional, for instance due to permanent structural modifications, or be physiologically triggered by agonist binding at an external and accessible specific site. Based on thestructures of agonists, AGPCRs may be divided according to pharmacological assays into many classes of receptors, each one comprising many types or sub-types of proteins, as differentiated by specific binding of inhibitors, all of them performing a multitude of functions. It is noteworthy that AGPCRs have been more recently cloned and their sequences of amino acids determined in a large scale, a condition that has allowed these receptors to be sorted by a new criterium. Sequence analyses have consistently matched functional assays for classification of AGPCRs except for a certain number of functionally unknown receptors which have been cataloged as orphan receptors. A colossal number of AGPCRs, more than 10,000 sequences belonging to more than 1,000 different types of receptors, may nowadays be multiply-aligned what has been enabling the determination of parameters of residue conservation and characterization of special motifs along the structure of these proteins. There are at the present time, high-resolution 3D structures for the following AGPCRs: inactive rhodopsin, retinal-free opsin, Beta adrenoceptor and adenosine receptors. Among them, hodopsin structures are reliable enough to be used as prototypes for analyses of residue conservation and mechanisms of activation of receptors, specially at the level of the more conserved structure in the cytosolic half of their 7TM bundle.
Descritores: Receptores Acoplados a Proteínas G/agonistas
Receptores Acoplados a Proteínas G/classificação
Receptores Acoplados a Proteínas G/fisiologia
-Adenosina
Receptores Adrenérgicos
Rodopsina
Tipo de Publ: Revisão
Responsável: BR33.1 - Divisão Técnica de Biblioteca e Documentação


  2 / 9 LILACS  
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Texto completo SciELO Brasil
Castrucci, A. M. L
Texto completo
Id: lil-556864
Autor: Lopes, G. J. D; Góis, C. C; Lima, L. H. R. G; Castrucci, A. M. L.
Título: Modulation of rhodopsin gene expression and signaling mechanisms evoked by endothelins in goldfish and murine pigment cell lines
Fonte: Braz. j. med. biol. res = Rev. bras. pesqui. méd. biol;43(9):828-836, Sept. 2010. ilus.
Idioma: en.
Resumo: Endothelins (ETs) and sarafotoxins (SRTXs) belong to a family of vasoconstrictor peptides, which regulate pigment migration and/or production in vertebrate pigment cells. The teleost Carassius auratus erythrophoroma cell line, GEM-81, and Mus musculus B16 melanocytes express rhodopsin, as well as the ET receptors, ETB and ETA, respectively. Both cell lines are photoresponsive, and respond to light with a decreased proliferation rate. For B16, the doubling time of cells kept in 14-h light (14L):10-h darkness (10D) was higher compared to 10L:14D, or to DD. The doubling time of cells kept in 10L:14D was also higher compared to DD. Using real-time PCR, we demonstrated that SRTX S6c (12-h treatment, 100 pM and 1 nM; 24-h treatment, 1 nM) and ET-1 (12-h treatment, 10 and 100 pM; 24- and 48-h treatments, 100 pM) increased rhodopsin mRNA levels in GEM-81 and B16 cells, respectively. This modulation involves protein kinase C (PKC) and the mitogen-activated protein kinase cascade in GEM-81 cells, and phospholipase C, Ca2+, calmodulin, a Ca2+/calmodulin-dependent kinase, and PKC in B16 cells. Cells were kept under constant darkness throughout the gene expression experiments. These results show that rhodopsin mRNA levels can be modulated by SRTXs/ETs in vertebrate pigment cells. It is possible that SRTX S6c binding to the ETB receptors in GEM-81 cells, and ET-1 binding to ETA receptors in B16 melanocytes, although activating diverse intracellular signaling mechanisms, mobilize transcription factors such as c-Fos, c-Jun, c-Myc, and neural retina leucine zipper protein. These activated transcription factors may be involved in the positive regulation of rhodopsin mRNA levels in these cell lines.
Descritores: Proliferação de Células/efeitos dos fármacos
Endotelinas/farmacologia
Rodopsina/efeitos dos fármacos
Vasoconstritores/farmacologia
Venenos de Víboras/farmacologia
-Linhagem Celular
Regulação da Expressão Gênica
Carpa Dourada
Sistema de Sinalização das MAP Quinases/efeitos dos fármacos
Sistema de Sinalização das MAP Quinases/genética
Reação em Cadeia da Polimerase
Proteína Quinase C/efeitos dos fármacos
Proteína Quinase C/genética
RNA Mensageiro/efeitos dos fármacos
RNA Mensageiro/genética
Rodopsina/genética
Rodopsina/metabolismo
Limites: Animais
Camundongos
Tipo de Publ: Research Support, Non-U.S. Gov't
Responsável: BR1.1 - BIREME


  3 / 9 LILACS  
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Id: lil-520041
Autor: Pereira, S. R. F; Silva, A. S; Bormann, E. P; Kuppinger, O.
Título: Association between a new 3q; 5q chromosomal translocation and dystrophy of human retinal pigment epithelium
Fonte: Genet. mol. res. (Online);6(4):1085-1090, 2007. ilus.
Idioma: en.
Resumo: Retinitis pigmentosa (RP) is a heterogeneous group of inherited retinal degeneration. This group of disorders essentially leads to blindness due to mutations in different genes. The genetic basis affected by sporadic and inherited autosomal dominant, autosomal recessive or X-linked mutations is complex. In humans, RP is in most cases associated with missense mutations in the rhodopsin gene (RHO). RHO plays an important role in phototransduction pathways. So far, few studies have described associations between chromosomal alterations and RP. In this study, we present a case report of a premature, 32-week-old male baby who suffered from retinopathy, facial dysmorphisms and other disorders. His chromosomes were analyzed by conventional and high-resolution chromosomal techniques. This analysis revealed structural aberrations on chromosomes 3 and 5 with an apparently balanced chromosomal translocation with karyotype 46,XY,t(3;5)(q25;q11.2). Remarkably, the 3q breakpoint on the long arm of chromosome 3 is located close to the physical RHO chromosomal gene location. In this study, we describe presumably for the first time a possible association between a 3q;5q chromosomal alteration and RP. We conclude that the new detected chromosomal translocation may lead either to loss or inactivation of the intragenic RHO gene or its respective gene regulatory region. As a consequence, the chromosomal aberration may be responsible for retinitis pigmentosa.
Descritores: /genética
CROMOSSOMOS HUMANOS PAR ABATTOIRS/genética
/genética
CROMOSSOMOS HUMANOS PAR ABDOMEN/genética
Degeneração Retiniana/genética
Recém-Nascido Prematuro
Translocação Genética
-Anormalidades Craniofaciais
Degeneração Retiniana/congênito
Rodopsina/genética
Limites: Humanos
Masculino
Recém-Nascido
Tipo de Publ: Relatos de Casos
Responsável: BR26.1 - Biblioteca Central


  4 / 9 LILACS  
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Texto completo SciELO Venezuela
Texto completo
Id: lil-517093
Autor: Medina, Rafael; Moller, Carolina; Perdomo, Deisy; Bubis, José.
Título: Aproximaciones de bioquímica clásica al estudio de la relación entre la estructura y la función de la rodopsina Y / Approaches to the study of classical biochemistry of the relationship between structure and function of the rhodopsin
Fonte: Arch. venez. farmacol. ter;27(1):5-13, 2008. ilus.
Idioma: es.
Resumo: La proteína fotorreceptora rodopsina (R) fue extraída de los segmentos externos de los bastoncillos de retinas bovinas con el detergente n-dodecil β-D-maltósido (DM) y purificada a homogeneidad mediante cromatografía de afinidad. El entrecruzamiento químico de la R y de la rodopsina fotoactivada (R*) con los agentes bifuncionales sulfo-succinimidilo 4-(N-maleimidometilo) ciclohexano-1-carboxilato (sulfo-SMCC) o m-maleimidobenzoilo-N-hidroxisuccinimido ester, sugirieron la naturaleza oligomérica de la proteína fotorreceptora. La caracterización de los parámetros hidrodinámicos de la R y la R* en presencia de 0.1% DM, mediante cromatografía de exclusión molecular y sedimentación sobre gradientes de sacarosa, permitió estimar los tamaños de los complejos R:DM y R*: DM. Los resultados concuerdan con una estructura cuaternaria dimérica tanto para la R como para la R*. La R entrecruzada con sulfo-SMCC, en presencia de luz, fue estabilizada en un fotointermediario que absorbió a ~ 470 nm. Experimentos de proteólisis con termolísina sobre los dímeros nativos de R y sobre los monómeros de R generados por medio del uso de altas concentraciones de DM, complementados con estudios de modelaje basados en la estructura cristalina reportada de la proteína, sugirieron que el reactivo sulfo-SMCC generó un entrecruzamiento intramolecular entre la Cys140 y la Lys248 de la R, el cual posiblemente es el responsable de la incapacidad de la proteína de sufrir el cambio conformacional requerido para llegar a su estado fotoactivado.
Descritores: Dimerização
Hibridização Genética
Retina/química
Rodopsina/análise
Percepção Visual
-Reações Bioquímicas/métodos
Limites: Bovinos
Animais
Tipo de Publ: Estudo de Avaliação
Responsável: VE1.1 - Biblioteca Humberto Garcia Arocha


  5 / 9 LILACS  
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Texto completo SciELO Chile
Texto completo
Id: lil-356878
Autor: Kosoy, Ana; Moller, Carolina; Perdomo, Deisy; Bubis, Jose.
Título: Identification of functionally important acidic residues in transducin by group-specific labeling
Fonte: Biol. Res;36(3/4):389-404, 2003. ilus, graf.
Idioma: en.
Resumo: Transducin (T), a GTP-binding protein involved in phototransduction of rod photoreceptor cells, is a heterotrimer arranged as two units, the alpha-subunit (T alpha) and the beta gamma-complex (T beta gamma). The role of the carboxyl groups in T was evaluated by labeling with N,N'-dicyclohexylcarbodiimide (DCCD) and 1-ethyl 3-(3-dimethylaminopropyl) carbodiimide (EDC). Only a minor effect on the binding of beta, gamma-imido guanosine 5'-triphosphate (GMPpNp) to T was observed in the presence of the hydrophobic carbodiimide, DCCD. Similarly, the GMPpNp binding activity of the reconstituted holoenzyme was not significantly affected when T alpha was combined with DCCD-treated T beta gamma. However, the binding of guanine nucleotides to the reconstituted T was approximately 50 per cent inhibited when DCCD-labeled T alpha was incubated with T beta gamma. In contrast, treatment of T with the hydrophilic carbodiimide, EDC, completely impaired its GMPpNp-binding ability. EDC-modified T was incapable of interacting with illuminated rhodopsin, as determined by sedimentation experiments. However, rhodopsin only partially protected against the inactivation of T. Additionally, analyses of trypsin digestion patterns showed that fluoroaluminate was not capable of activating the EDC-labeled T sample. The function of the reconstituted holoenzyme was also disrupted when EDC-modified T alpha was combined with T beta gamma, and when EDC-treated T beta gamma was incubated with T alpha.
Descritores: Dicicloexilcarbodi-Imida
Rodopsina
Segmento Externo da Célula Bastonete
Transducina
-Transdução de Sinais
Transducina
Limites: Animais
Bovinos
Responsável: BR1.1 - BIREME


  6 / 9 LILACS  
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Id: lil-228574
Autor: Bubis, J.
Título: Improved purification of transducin subunits from bovine retinal rod outer segments
Fonte: Biol. Res;28(4):291-9, 1995.
Idioma: en.
Resumo: Transducin serves as a mediator between the receptor protein, rhodopsin, and the effector protein, cGMP phosphodiesterase, in the visual process. Transducin is a protein composed of three polypeptides: T alpha, T beta, and T gamma, and acts as two functional units, the alpha-subunit and the beta gamma-complex. In the present study, I describe an efficient and fast method of purifying T alpha and T beta gamma using chromatography on a blue agarose column connected in tandem with an omega-amino octylagarose column. The recombination of T alpha and T beta gamma reconstitutes the functional heterotrimeric holoprotein, as demonstrated by the recovery of three native properties of transducin: 1) its capacity to exchange guanine nucleotide, 2) its GTP hydrolytic activity, and 3) the ADP-ribosylation of T alpha catalysed by pertussis toxin
Descritores: Rodopsina/química
Segmento Externo da Célula Bastonete/química
Transducina/isolamento & purificação
-Cromatografia em Agarose/métodos
Eletroforese em Gel de Poliacrilamida
Inibidores da Síntese de Proteínas/farmacologia
Sefarose/análogos & derivados
Sefarose/farmacologia
Triazinas/farmacologia
Limites: Animais
Bovinos
Tipo de Publ: Research Support, Non-U.S. Gov't
Responsável: BR1.1 - BIREME


  7 / 9 LILACS  
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Id: lil-228523
Autor: Palacios, A. G; Goldsmith, T. H.
Título: Visual transduction in vertebrate rods
Fonte: Biol. Res;29(3):313-7, 1996.
Idioma: en.
Descritores: Transdução de Sinal Luminoso/fisiologia
Células Fotorreceptoras Retinianas Bastonetes/fisiologia
Vertebrados/fisiologia
-Adaptação Ocular/fisiologia
Adaptação à Escuridão/fisiologia
Rodopsina/fisiologia
Limites: Animais
Gatos
Bovinos
Humanos
Coelhos
Ratos
Tipo de Publ: Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, P.H.S.
Responsável: BR1.1 - BIREME


  8 / 9 LILACS  
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Id: lil-225980
Autor: Bubis, José.
Título: Effect of detergents and lipids on transducin photoactivation by rhodopsin
Fonte: Biol. Res;31(1):59-71, 1998. tab, graf.
Idioma: en.
Projeto: Universidad Simón Bolívar. Decanato de Investigación y Desarrollo.
Resumo: Rhodopsin samples, isolated using four different extraction procedures, were used to investigate the photodependent activation of the GTPase activity of transducin. A complete inhibition of transducin light-dependent GTP hydrolytic activity was observed when rhodopsin purified in the presence of 1 per cent digitonin, following rod outer segment (ROS) solubilization with 1 per cent 3-[(3-cholamidopropyl) dimethylammonio]-1-propane-sulfonate (CHAPS), WAS used for its activation [0 pmol of inorganic phosphate (Pi) released/min/pmol of rhodopsin]. Rhodopsin, isolated in the presence of 1 per cent digitonin following ROS solubilization with 1 per cent digitonin, was capable of stimulating slightly transducin GTPase activity, with an initial rate of 1 pmol of GTP hydrolyzed/min/pmol of rhodopsin. However, rhodopsin purified in the presence of 0.2 per cent n-dodecyl-beta-D-maltoside (DM), following ROS solubilization with either 1 per cent CHAPS or 1 per cent DM, stimulated the enzymatic activity of transducin in a light-dependent manner, with an initial rate of 5 pmol of Pi released/min/pmol of rhodopsin. Addition of 0.075 per cent egg phosphatidylcholine (PC) to the four different solubilized rhodopsin samples significantly enhanced light-stimulated GTP hydrolysis by transducin, with initial rates increasing from 0 to 1, 1 to 2, and 5 to 30 pmol of Pi released/min/pmol of rhodopsin, respectively. Furthermore, DM-solubilized rhodopsin induced the hydrolysis of the maximun amount of GTP by transducin at 0.0075 per cent PC, while digitonin-solubilized rhodopsin only stimulated the GTPase activity of transducin to a similar value, when the amount of the photoreceptor protein was increased 4-fold and 0.15 per cent PC was added to the assay mixture. These results suggest that the effective photoactivation of transducin by rhodopsin requires phospholipids, which seem to be differentially eliminated with the detergent extraction procedure utilized during ROS membranes solubilization and photopigment isolation.
Descritores: Detergentes
Lipídeos
Estimulação Luminosa
Rodopsina
Transducina
-GTP Fosfo-Hidrolases/metabolismo
Retina
Rodopsina/isolamento & purificação
Transducina/isolamento & purificação
Transducina/metabolismo
Limites: Animais
Bovinos
Responsável: BR1.1 - BIREME


  9 / 9 LILACS  
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Yamane, Riuitiro
Id: lil-73173
Autor: Dantas, Aldamir Morterá; Yamane, Riuitiro; Câmara, Antônio Geraldo; Poletti, Selma.
Título: O estudo do potencial receptor precoce / Early receptor potential
Fonte: Rev. bras. oftalmol;47(6):325-9, dez. 1988. ilus.
Idioma: pt.
Resumo: Os autores estudaram o E. R. P., no atobá (Sula leucogaster), no coelho (Oryctolagus cucniculus) e no homem. Discutem sua origem, obtençäo e interesse clínico
Descritores: Potenciais Evocados Visuais
Pigmentos da Retina
-Eletrorretinografia
Estimulação Luminosa
Células Fotorreceptoras de Vertebrados
Rodopsina
Limites: Coelhos
Animais
Humanos
Responsável: BR1.1 - BIREME



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