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Pesquisa : D08.811.277.040.330.300.200.800 [Categoria DeCS]
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[PMID]:28747438
[Au] Autor:Seno K; Hayashi F
[Ad] Endereço:From the Department of Biology, Faculty of Medicine, and.
[Ti] Título:Palmitoylation is a prerequisite for dimerization-dependent raftophilicity of rhodopsin.
[So] Source:J Biol Chem;292(37):15321-15328, 2017 09 15.
[Is] ISSN:1083-351X
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:The visual photopigment rhodopsin (Rh) is a prototypical G protein-coupled receptor (GPCR) responsible for initiation of the phototransduction cascade in rod photoreceptors. Similar to other GPCRs, Rh can form dimers or even higher oligomers and tends to have a supramolecular organization that is likely important in the dim light response. Rh also exhibits high affinity for lipid rafts ( raftophilicity) upon light-dependent binding with the cognate G protein transducin (G ), suggesting the presence of lipid raft-like domains in the retinal disk membrane and their importance in phototransduction. However, the relationship between Rh oligomerization and lipid rafts in the disk membrane remains to be explored. Given previous findings that G binds to dimeric Rh and that Rh is posttranslationally modified with two highly raftophilic palmitoyl moieties, we hypothesized that Rh becomes raftophilic upon dimerization. Here, using biochemical assays, we found that Rh*-G complexes in the detergent-resistant membrane are partially resistant to cholesterol depletion by methyl-ß-cyclodextrin and that the Rh-to-G stoichiometry in this methyl-ß-cyclodextrin-resistant complex is 2:1. Next, we found that IgG-mediated Rh-Rh cross-linking renders Rh highly raftophilic, supporting the premise that Rh becomes raftophilic upon dimerization. Rh depalmitoylation via reduction of thioester linkages blocked the translocation of IgG-cross-linked Rh to the detergent-resistant membrane, highlighting that the two palmitoyl moieties are important for the dimerization-dependent raftophilicity of Rh. These results indicate that palmitoylated GPCRs such as Rh can acquire raftophilicity upon G protein-stabilized dimerization and thereby organize receptor-cluster rafts by recruiting raftophilic lipids.
[Mh] Termos MeSH primário: Lipoilação
Microdomínios da Membrana/metabolismo
Modelos Moleculares
Processamento de Proteína Pós-Traducional
Rana catesbeiana/fisiologia
Rodopsina/metabolismo
Segmento Externo da Célula Bastonete/metabolismo
[Mh] Termos MeSH secundário: Proteínas de Anfíbios/química
Proteínas de Anfíbios/metabolismo
Animais
Anticorpos Monoclonais/metabolismo
Cisteína/química
Cistina/química
Adaptação à Escuridão
Dimerização
Interações Hidrofóbicas e Hidrofílicas
Cinética
Luz
Lipoilação/efeitos da radiação
Microdomínios da Membrana/química
Microdomínios da Membrana/efeitos da radiação
Oxirredução
Conformação Proteica/efeitos da radiação
Multimerização Proteica/efeitos da radiação
Processamento de Proteína Pós-Traducional/efeitos da radiação
Estabilidade Proteica/efeitos da radiação
Rodopsina/química
Segmento Externo da Célula Bastonete/química
Segmento Externo da Célula Bastonete/efeitos da radiação
Transducina/química
Transducina/metabolismo
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
0 (Amphibian Proteins); 0 (Antibodies, Monoclonal); 48TCX9A1VT (Cystine); 9009-81-8 (Rhodopsin); EC 3.6.5.1 (Transducin); K848JZ4886 (Cysteine)
[Em] Mês de entrada:1709
[Cu] Atualização por classe:171230
[Lr] Data última revisão:
171230
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170728
[St] Status:MEDLINE
[do] DOI:10.1074/jbc.M117.804880


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[PMID]:28842475
[Au] Autor:Dessauer CW
[Ad] Endereço:From the Department of Integrative Biology and Pharmacology, McGovern Medical School, University of Texas Health Science Center, Houston, Texas 77030 carmen.w.dessauer@uth.tmc.edu.
[Ti] Título:Shining a light on GPCR complexes.
[So] Source:J Biol Chem;292(34):14290-14291, 2017 Aug 25.
[Is] ISSN:1083-351X
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:The G protein-coupled receptor (GPCR) signaling pathways mediating information exchange across the cell membrane are central to a variety of biological processes and therapeutic strategies, but visualizing the molecular-level details of this exchange has been difficult for all but a few GPCR-G protein complexes. A study by Gao now reports new strategies and tools to obtain receptor complexes in a near-native state, revealing insights into the gross conformational features of rhodopsin-transducin interactions and setting the stage for future studies.
[Mh] Termos MeSH primário: Proteínas do Olho/metabolismo
Subunidades beta da Proteína de Ligação ao GTP/metabolismo
Subunidades gama da Proteína de Ligação ao GTP/metabolismo
Modelos Moleculares
Rodopsina/metabolismo
Transducina/metabolismo
[Mh] Termos MeSH secundário: Animais
Proteínas do Olho/química
Subunidades beta da Proteína de Ligação ao GTP/química
Subunidades gama da Proteína de Ligação ao GTP/química
Seres Humanos
Domínios e Motivos de Interação entre Proteínas/efeitos da radiação
Multimerização Proteica/efeitos da radiação
Rodopsina/química
Segmento Externo da Célula Bastonete/enzimologia
Segmento Externo da Célula Bastonete/metabolismo
Segmento Externo da Célula Bastonete/efeitos da radiação
Transducina/química
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Eye Proteins); 0 (GTP-Binding Protein beta Subunits); 0 (GTP-Binding Protein gamma Subunits); 9009-81-8 (Rhodopsin); EC 3.6.5.1 (Transducin)
[Em] Mês de entrada:1709
[Cu] Atualização por classe:170912
[Lr] Data última revisão:
170912
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170827
[St] Status:MEDLINE
[do] DOI:10.1074/jbc.H117.797100


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[PMID]:28655769
[Au] Autor:Gao Y; Westfield G; Erickson JW; Cerione RA; Skiniotis G; Ramachandran S
[Ad] Endereço:From the Department of Chemistry and Chemical Biology, Baker Laboratory, and.
[Ti] Título:Isolation and structure-function characterization of a signaling-active rhodopsin-G protein complex.
[So] Source:J Biol Chem;292(34):14280-14289, 2017 Aug 25.
[Is] ISSN:1083-351X
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:The visual photo-transduction cascade is a prototypical G protein-coupled receptor (GPCR) signaling system, in which light-activated rhodopsin (Rho*) is the GPCR catalyzing the exchange of GDP for GTP on the heterotrimeric G protein transducin (G ). This results in the dissociation of G into its component α -GTP and ß Î³ subunit complex. Structural information for the Rho*-G complex will be essential for understanding the molecular mechanism of visual photo-transduction. Moreover, it will shed light on how GPCRs selectively couple to and activate their G protein signaling partners. Here, we report on the preparation of a stable detergent-solubilized complex between Rho* and a heterotrimer (G *) comprising a Gα /Gα chimera (α *) and ß Î³ The complex was formed on native rod outer segment membranes upon light activation, solubilized in lauryl maltose neopentyl glycol, and purified with a combination of affinity and size-exclusion chromatography. We found that the complex is fully functional and that the stoichiometry of Rho* to Gα * is 1:1. The molecular weight of the complex was calculated from small-angle X-ray scattering data and was in good agreement with a model consisting of one Rho* and one G *. The complex was visualized by negative-stain electron microscopy, which revealed an architecture similar to that of the ß -adrenergic receptor-G complex, including a flexible α * helical domain. The stability and high yield of the purified complex should allow for further efforts toward obtaining a high-resolution structure of this important signaling complex.
[Mh] Termos MeSH primário: Proteínas do Olho/metabolismo
Subunidades beta da Proteína de Ligação ao GTP/metabolismo
Subunidades gama da Proteína de Ligação ao GTP/metabolismo
Modelos Moleculares
Rodopsina/metabolismo
Transducina/metabolismo
[Mh] Termos MeSH secundário: Animais
Bovinos
Cristalografia por Raios X
Detergentes/química
Proteínas do Olho/química
Proteínas do Olho/genética
Proteínas do Olho/isolamento & purificação
Subunidades beta da Proteína de Ligação ao GTP/química
Subunidades beta da Proteína de Ligação ao GTP/isolamento & purificação
Subunidades gama da Proteína de Ligação ao GTP/química
Subunidades gama da Proteína de Ligação ao GTP/isolamento & purificação
Luz
Microscopia Eletrônica
Fragmentos de Peptídeos/química
Fragmentos de Peptídeos/genética
Fragmentos de Peptídeos/isolamento & purificação
Fragmentos de Peptídeos/metabolismo
Conformação Proteica/efeitos da radiação
Multimerização Proteica/efeitos da radiação
Estabilidade Proteica/efeitos da radiação
Proteínas Recombinantes de Fusão/química
Proteínas Recombinantes de Fusão/isolamento & purificação
Proteínas Recombinantes de Fusão/metabolismo
Retina/enzimologia
Retina/metabolismo
Retina/efeitos da radiação
Rodopsina/química
Rodopsina/isolamento & purificação
Segmento Externo da Célula Bastonete/enzimologia
Segmento Externo da Célula Bastonete/metabolismo
Segmento Externo da Célula Bastonete/efeitos da radiação
Espalhamento a Baixo Ângulo
Solubilidade
Transducina/química
Transducina/genética
Transducina/isolamento & purificação
Difração de Raios X
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Detergents); 0 (Eye Proteins); 0 (GTP-Binding Protein beta Subunits); 0 (GTP-Binding Protein gamma Subunits); 0 (Peptide Fragments); 0 (Recombinant Fusion Proteins); 9009-81-8 (Rhodopsin); EC 3.6.5.1 (Transducin)
[Em] Mês de entrada:1709
[Cu] Atualização por classe:170912
[Lr] Data última revisão:
170912
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170629
[St] Status:MEDLINE
[do] DOI:10.1074/jbc.M117.797100


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[PMID]:28559440
[Au] Autor:Zheng K; Lu P; Delpapa E; Bellve K; Deng R; Condon JC; Fogarty K; Lifshitz LM; Simas TAM; Shi F; ZhuGe R
[Ad] Endereço:College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, China.
[Ti] Título:Bitter taste receptors as targets for tocolytics in preterm labor therapy.
[So] Source:FASEB J;31(9):4037-4052, 2017 Sep.
[Is] ISSN:1530-6860
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Preterm birth (PTB) is the leading cause of neonatal mortality and morbidity, with few prevention and treatment options. Uterine contraction is a central feature of PTB, so gaining new insights into the mechanisms of this contraction and consequently identifying novel targets for tocolytics are essential for more successful management of PTB. Here we report that myometrial cells from human and mouse express bitter taste receptors (TAS2Rs) and their canonical signaling components ( G-protein gustducin and phospholipase C ß2). Bitter tastants can completely relax myometrium precontracted by different uterotonics. In isolated single mouse myometrial cells, a phenotypical bitter tastant (chloroquine, ChQ) reverses the rise in intracellular Ca concentration ([Ca ] ) and cell shortening induced by uterotonics, and this reversal effect is inhibited by pertussis toxin and by genetic deletion of α-gustducin. In human myometrial cells, knockdown of TAS2R14 but not TAS2R10 inhibits ChQ's reversal effect on an oxytocin-induced rise in [Ca ] Finally, ChQ prevents mouse PTBs induced by bacterial endotoxin LPS or progesterone receptor antagonist mifepristone more often than current commonly used tocolytics, and this prevention is largely lost in α-gustducin-knockout mice. Collectively, our results reveal that activation of the canonical TAS2R signaling system in myometrial cells produces profound relaxation of myometrium precontracted by a broad spectrum of contractile agonists, and that targeting TAS2Rs is an attractive approach to developing effective tocolytics for PTB management.-Zheng, K., Lu, P., Delpapa, E., Bellve, K., Deng, R., Condon, J. C., Fogarty, K., Lifshitz, L. M., Simas, T. A. M., Shi, F., ZhuGe, R. Bitter taste receptors as targets for tocolytics in preterm labor therapy.
[Mh] Termos MeSH primário: Regulação da Expressão Gênica/fisiologia
Miométrio/citologia
Trabalho de Parto Prematuro/tratamento farmacológico
Receptores Acoplados a Proteínas-G/metabolismo
[Mh] Termos MeSH secundário: Albuterol
Animais
Cálcio/metabolismo
Cloroquina
Feminino
Seres Humanos
Sulfato de Magnésio
Camundongos
Contração Muscular/efeitos dos fármacos
Contração Muscular/fisiologia
Músculo Liso/efeitos dos fármacos
Músculo Liso/fisiologia
Ocitocina/farmacologia
Fenantrolinas
Gravidez
Compostos de Amônio Quaternário
Receptores Acoplados a Proteínas-G/genética
Transducina/genética
Transducina/metabolismo
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Phenanthrolines); 0 (Quaternary Ammonium Compounds); 0 (Receptors, G-Protein-Coupled); 147979-21-3 (gustducin); 4YK5Z54AT2 (denatonium benzoate); 50-56-6 (Oxytocin); 7487-88-9 (Magnesium Sulfate); 886U3H6UFF (Chloroquine); EC 3.6.5.1 (Transducin); QF8SVZ843E (Albuterol); SY7Q814VUP (Calcium); W4X6ZO7939 (1,10-phenanthroline)
[Em] Mês de entrada:1710
[Cu] Atualização por classe:171109
[Lr] Data última revisão:
171109
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170601
[St] Status:MEDLINE
[do] DOI:10.1096/fj.201601323RR


  5 / 1461 MEDLINE  
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[PMID]:28473692
[Au] Autor:Kaylor JJ; Xu T; Ingram NT; Tsan A; Hakobyan H; Fain GL; Travis GH
[Ad] Endereço:Jules Stein Eye Institute, University of California Los Angeles School of Medicine, Los Angeles, California, 90095, USA.
[Ti] Título:Blue light regenerates functional visual pigments in mammals through a retinyl-phospholipid intermediate.
[So] Source:Nat Commun;8(1):16, 2017 05 04.
[Is] ISSN:2041-1723
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:The light absorbing chromophore in opsin visual pigments is the protonated Schiff base of 11-cis-retinaldehyde (11cRAL). Absorption of a photon isomerizes 11cRAL to all-trans-retinaldehyde (atRAL), briefly activating the pigment before it dissociates. Light sensitivity is restored when apo-opsin combines with another 11cRAL to form a new visual pigment. Conversion of atRAL to 11cRAL is carried out by enzyme pathways in neighboring cells. Here we show that blue (450-nm) light converts atRAL specifically to 11cRAL through a retinyl-phospholipid intermediate in photoreceptor membranes. The quantum efficiency of this photoconversion is similar to rhodopsin. Photoreceptor membranes synthesize 11cRAL chromophore faster under blue light than in darkness. Live mice regenerate rhodopsin more rapidly in blue light. Finally, whole retinas and isolated cone cells show increased photosensitivity following exposure to blue light. These results indicate that light contributes to visual-pigment renewal in mammalian rods and cones through a non-enzymatic process involving retinyl-phospholipids.It is currently thought that visual pigments in vertebrate photoreceptors are regenerated exclusively through enzymatic cycles. Here the authors show that mammalian photoreceptors also regenerate opsin pigments in light through photoisomerization of N-ret-PE (N-retinylidene-phosphatidylethanolamine.
[Mh] Termos MeSH primário: Fosfatidiletanolaminas/metabolismo
Células Fotorreceptoras Retinianas Cones/efeitos da radiação
Células Fotorreceptoras Retinianas Bastonetes/efeitos da radiação
Retinaldeído/metabolismo
Retinoides/metabolismo
Rodopsina/metabolismo
[Mh] Termos MeSH secundário: Animais
Apoproteínas/genética
Apoproteínas/metabolismo
Regulação da Expressão Gênica
Luz
Transdução de Sinal Luminoso
Camundongos
Opsinas/genética
Opsinas/metabolismo
Processos Fotoquímicos
Células Fotorreceptoras Retinianas Cones/citologia
Células Fotorreceptoras Retinianas Cones/metabolismo
Células Fotorreceptoras Retinianas Bastonetes/citologia
Células Fotorreceptoras Retinianas Bastonetes/metabolismo
Rodopsina/genética
Transducina/genética
Transducina/metabolismo
Visão Ocular/fisiologia
Visão Ocular/efeitos da radiação
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, N.I.H., EXTRAMURAL; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
0 (Apoproteins); 0 (N-retinylidene-phosphatidylethanolamine); 0 (Opsins); 0 (Phosphatidylethanolamines); 0 (Retinoids); 9009-81-8 (Rhodopsin); EC 3.6.5.1 (Transducin); RR725D715M (Retinaldehyde)
[Em] Mês de entrada:1711
[Cu] Atualização por classe:171101
[Lr] Data última revisão:
171101
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170506
[St] Status:MEDLINE
[do] DOI:10.1038/s41467-017-00018-4


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[PMID]:28429344
[Au] Autor:Li DD; Liu Y; Xue L; Su DY; Pang WY
[Ad] Endereço:Department of Endocrinology, Henan University Huaihe Hospital, Kaifeng, Henan Province, China. wuyanpangdr@163.com.
[Ti] Título:Up-regulation of microRNA-367 promotes liver steatosis through repressing TBL1 in obese mice.
[So] Source:Eur Rev Med Pharmacol Sci;21(7):1598-1603, 2017 Apr.
[Is] ISSN:2284-0729
[Cp] País de publicação:Italy
[La] Idioma:eng
[Ab] Resumo:OBJECTIVE: Increasing evidence has demonstrated that microRNAs (miRNAs) play a critical role in the progression of metabolic disorders, including obesity-induced non-alcoholic fatty liver disease (NAFLD). In the present study, the expression and function of miR-367 were investigated. MATERIALS AND METHODS: C57BL/6 male mice aged 8 weeks were fed with a normal diet (ND) or high-fat-diet (HFD). The expression levels of miR-367 were analyzed in livers from two groups of mice by quantitative real-time PCR. Adenovirus containing miR-367 or negative control (NC) were constructed and administrated into C57BL/6 mice by tail vain injection. Potential targets of miR-367 were screened by miRWalk software and luciferase reporter assays. Mutagenesis analysis and Western blots were used to further determine the target of miR-367 in obese mice. RESULTS:  We found that the expression of hepatic miR-367 was up-regulated in obese mice. In vitro and in vivo studies further demonstrated that overexpression of miR-367 mimics promoted triglyceride accumulation in cells and lean mice. At the molecular level, transducin beta-like 1 (TBL1), a coactivator of nuclear receptor peroxisome proliferator-activated receptor (PPAR) α, was identified as a direct target of miR-367. As a result, miR-367 overexpression resulted in an inhibition of fatty acid oxidation, leading to hepatosteatosis. CONCLUSIONS: Our data suggest miR-367/TBL1 regulatory pathway might have an important role for in the development of NAFLD.
[Mh] Termos MeSH primário: MicroRNAs/biossíntese
Hepatopatia Gordurosa não Alcoólica
Transducina/metabolismo
[Mh] Termos MeSH secundário: Animais
Dieta Hiperlipídica
Regulação da Expressão Gênica
Fígado/metabolismo
Masculino
Camundongos
Camundongos Endogâmicos C57BL
Camundongos Obesos
Hepatopatia Gordurosa não Alcoólica/etiologia
Hepatopatia Gordurosa não Alcoólica/metabolismo
Transducina/antagonistas & inibidores
Regulação para Cima
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (MIRN367 microRNA, mouse); 0 (MicroRNAs); 0 (Tbl1x protein, mouse); EC 3.6.5.1 (Transducin)
[Em] Mês de entrada:1708
[Cu] Atualização por classe:170804
[Lr] Data última revisão:
170804
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170422
[St] Status:MEDLINE


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[PMID]:28347645
[Au] Autor:Lamb TD; Hunt DM
[Ad] Endereço:Eccles Institute of Neuroscience, John Curtin School of Medical Research, The Australian National University, ACT 2600, Australia. Electronic address: Trevor.Lamb@anu.edu.au.
[Ti] Título:Evolution of the vertebrate phototransduction cascade activation steps.
[So] Source:Dev Biol;431(1):77-92, 2017 11 01.
[Is] ISSN:1095-564X
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:We examine the molecular phylogeny of the proteins underlying the activation steps of vertebrate phototransduction, for both agnathan and jawed vertebrate taxa. We expand the number of taxa analysed and we update the alignment and tree building methodology from a previous analysis. For each of the four primary components (the G-protein transducin alpha subunit, Gα , the cyclic GMP phosphodiesterase, PDE6, and the alpha and beta subunits of the cGMP-gated ion channel, CNGC), the phylogenies appear consistent with expansion from an ancestral proto-vertebrate cascade during two rounds of whole-genome duplication followed by divergence of the agnathan and jawed vertebrate lineages. In each case, we consider possible scenarios for the underlying gene duplications and losses, and we apply relevant constraints to the tree construction. From tests of the topology of the resulting trees, we obtain a scenario for the expansion of each component during 2R that accurately fits the observations. Similar analysis of the visual opsins indicates that the only expansion to have occurred during 2R was the formation of Rh1 and Rh2. Finally, we propose a hypothetical scenario for the conversion of an ancestral chordate cascade into the proto-vertebrate phototransduction cascade, prior to whole-genome duplication. Together, our models provide a plausible account for the origin and expansion of the vertebrate phototransduction cascade.
[Mh] Termos MeSH primário: Evolução Molecular
Visão Ocular/genética
Visão Ocular/fisiologia
[Mh] Termos MeSH secundário: Animais
Nucleotídeo Cíclico Fosfodiesterase do Tipo 6/genética
Nucleotídeo Cíclico Fosfodiesterase do Tipo 6/fisiologia
Canais de Cátion Regulados por Nucleotídeos Cíclicos/genética
Canais de Cátion Regulados por Nucleotídeos Cíclicos/fisiologia
Duplicação Gênica
Seres Humanos
Modelos Genéticos
Opsinas/genética
Opsinas/fisiologia
Células Fotorreceptoras de Vertebrados/fisiologia
Filogenia
Transducina/genética
Transducina/fisiologia
Vertebrados/genética
Vertebrados/crescimento & desenvolvimento
Vertebrados/fisiologia
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
0 (Cyclic Nucleotide-Gated Cation Channels); 0 (Opsins); EC 3.1.4.35 (Cyclic Nucleotide Phosphodiesterases, Type 6); EC 3.6.5.1 (Transducin)
[Em] Mês de entrada:1710
[Cu] Atualização por classe:171111
[Lr] Data última revisão:
171111
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170329
[St] Status:MEDLINE


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[PMID]:27980002
[Au] Autor:Steensels S; Lannoo M; Avau B; Laermans J; Vancleef L; Farré R; Verbeke K; Depoortere I
[Ad] Endereço:TARGIDKU Leuven, Leuven, Belgium.
[Ti] Título:The role of nutrient sensing in the metabolic changes after gastric bypass surgery.
[So] Source:J Endocrinol;232(3):363-376, 2017 Mar.
[Is] ISSN:1479-6805
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:Taste receptors coupled to the gustatory G-protein, gustducin, on enteroendocrine cells sense nutrients to regulate gut hormone release. During Roux-en-Y gastric bypass (RYGB) surgery, the altered nutrient flow to more distal regions can affect gustducin-mediated gut hormone release and hence energy and glucose homeostasis. We studied the role of gustducin-mediated signaling in the metabolic improvements and intestinal adaptations along the gut after RYGB surgery in wild-type (WT) and α-gustducin (α-gust ) mice. RYGB surgery decreased body weight in WT and α-gust mice, whereas food intake was only decreased in WT mice. Pair-feeding to the RYGB group improved glucose homeostasis to a similar extent in WT mice. GLP1 levels were increased in both genotypes, PYY levels in α-gust mice and octanoyl ghrelin levels were not affected after RYGB surgery. In WT mice, nutrients act via α-gustducin to increase L-cell differentiation (foregut) and L-cell number (foregut and hindgut) in a region-dependent manner. In α-gust mice, the effect on gut hormone levels is probably tuned via increased peptide sensor and glucose transporter expression in the Roux limb and increased caecal butyrate and propionate levels in the hindgut that activate free fatty acid receptors. Finally, signaling via α-gustducin plays a role in the increased ion transport of the foregut but not in the improvement in colonic barrier function. In conclusion, RYGB surgery decreased body weight in both WT and α-gust mice. Elevated plasma GLP1 and PYY levels might mediate this effect, although α-gustducin differentially affects several regulatory systems in the foregut and hindgut, tuning gut hormone release.
[Mh] Termos MeSH primário: Glicemia/metabolismo
Metabolismo Energético/fisiologia
Derivação Gástrica
Transducina/genética
[Mh] Termos MeSH secundário: Animais
Peso Corporal/fisiologia
Contagem de Células
Ingestão de Alimentos/fisiologia
Células Enteroendócrinas/metabolismo
Peptídeo 1 Semelhante ao Glucagon/sangue
Camundongos
Camundongos Knockout
Transdução de Sinais/fisiologia
Transducina/metabolismo
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Blood Glucose); 147979-21-3 (gustducin); 89750-14-1 (Glucagon-Like Peptide 1); EC 3.6.5.1 (Transducin)
[Em] Mês de entrada:1706
[Cu] Atualização por classe:170620
[Lr] Data última revisão:
170620
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:161217
[St] Status:MEDLINE
[do] DOI:10.1530/JOE-16-0541


  9 / 1461 MEDLINE  
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[PMID]:27941594
[Au] Autor:Steensels S; Vancleef L; Depoortere I
[Ad] Endereço:Gut Peptide Lab, Translational Research Center for Gastrointestinal Disorders (TARGID), University of Leuven-KU Leuven, 3000 Leuven, Belgium. sandra.steensels@kuleuven.be.
[Ti] Título:The Sweetener-Sensing Mechanisms of the Ghrelin Cell.
[So] Source:Nutrients;8(12), 2016 Dec 07.
[Is] ISSN:2072-6643
[Cp] País de publicação:Switzerland
[La] Idioma:eng
[Ab] Resumo:Carbohydrate administration decreases plasma levels of the 'hunger hormone' ghrelin. The ghrelin cell is co-localized with the sweet taste receptor subunit, TAS1R3, and the gustatory G-protein, gustducin, both involved in the sensing of sweeteners by entero-endocrine cells. This study investigated the role of gustducin-mediated sweet taste receptor signaling on ghrelin secretion in a gastric ghrelinoma cell line, tissue segments and mice. The monosaccharide d-glucose and low-intensity sweetener oligofructose (OFS) decreased ( < 0.001) ghrelin secretion while the high-intensity sweetener sucralose increased ( < 0.001) ghrelin secretion in vitro. These effects were not mediated via the sweet taste receptor or glucose transporters (the sodium-dependent glucose cotransporter SGLT-1 and GLUT2). The effect of these compounds was mimicked ex vivo in gastric and jejunal segments from both wild type (WT) and α-gustducin knockout (α-gust ) mice. In vivo, the sensing of d-glucose was polarized since intragastric but not intravenous administration of d-glucose decreased ( < 0.05) ghrelin levels in an α-gustducin independent manner which involved inhibition of duodenal ghrelin release. In contrast, neither OFS nor sucralose affected ghrelin secretion in vivo. In conclusion, α-gustducin-mediated sweet taste receptor signaling does not play a functional role in the sensing of carbohydrates, or low- or high-intensity sweeteners by the ghrelin cell.
[Mh] Termos MeSH primário: Grelina/metabolismo
Estômago/metabolismo
Edulcorantes/metabolismo
[Mh] Termos MeSH secundário: Animais
Linhagem Celular Tumoral
Regulação da Expressão Gênica/fisiologia
Jejuno/metabolismo
Masculino
Camundongos
Camundongos Endogâmicos C57BL
Camundongos Knockout
RNA Mensageiro
Transdução de Sinais
Transducina/metabolismo
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Ghrelin); 0 (RNA, Messenger); 0 (Sweetening Agents); 147979-21-3 (gustducin); EC 3.6.5.1 (Transducin)
[Em] Mês de entrada:1704
[Cu] Atualização por classe:170403
[Lr] Data última revisão:
170403
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:161213
[St] Status:MEDLINE


  10 / 1461 MEDLINE  
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Fotocópia
[PMID]:27753525
[Au] Autor:Yao J; Jia L; Feathers K; Lin C; Khan NW; Klionsky DJ; Ferguson TA; Zacks DN
[Ad] Endereço:a Department of Ophthalmology and Visual Sciences , University of Michigan , Ann Arbor , MI , USA.
[Ti] Título:Autophagy-mediated catabolism of visual transduction proteins prevents retinal degeneration.
[So] Source:Autophagy;12(12):2439-2450, 2016 Dec.
[Is] ISSN:1554-8635
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Autophagy is a lysosomal degradation pathway critical to preventing the accumulation of cytotoxic proteins. Deletion of the essential autophagy gene Atg5 from the rod photoreceptors of the retina (atg5 mouse) results in the accumulation of the phototransduction protein transducin and the degeneration of these neurons. The purpose of this study is to test the hypothesis that autophagic degradation of visual transduction proteins prevents retinal degeneration. Targeted deletion of both Gnat1 (a gene encoding the α subunit of the heterotrimeric G-protein transducin) and Atg5 in the rod photoreceptors resulted in a significantly decreased rate of rod cell degeneration as compared to the atg5 mouse retina, and considerable preservation of photoreceptors. Supporting this we used a novel technique to immunoprecipitate green fluorescent protein (GFP)-tagged autophagosomes from the retinas of the GFP-LC3 mice and demonstrated that the visual transduction proteins transducin and ARR/arrestin are associated with autophagosome-specific proteins. Altogether, this study shows that degradation of phototransduction proteins by autophagy is necessary to prevent retinal degeneration. In addition, we demonstrate a simple and easily reproducible immunoisolation technique for enrichment of autophagosomes from the GFP-LC3 mouse retina, providing a novel application to the study of autophagosome contents across different organs and specific cell types in vivo.
[Mh] Termos MeSH primário: Autofagia
Proteínas do Olho/metabolismo
Transdução de Sinal Luminoso
Proteólise
Degeneração Retiniana/metabolismo
Degeneração Retiniana/patologia
[Mh] Termos MeSH secundário: Animais
Autofagossomos/metabolismo
Proteína 5 Relacionada à Autofagia/metabolismo
Linhagem Celular
Cruzamentos Genéticos
Feminino
Subunidades alfa de Proteínas de Ligação ao GTP/deficiência
Subunidades alfa de Proteínas de Ligação ao GTP/metabolismo
Proteínas de Fluorescência Verde/metabolismo
Masculino
Camundongos
Camundongos Knockout
Reprodutibilidade dos Testes
Células Fotorreceptoras Retinianas Cones/metabolismo
Células Fotorreceptoras Retinianas Cones/patologia
Transducina/deficiência
Transducina/metabolismo
Transfecção
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Atg5 protein, mouse); 0 (Autophagy-Related Protein 5); 0 (Eye Proteins); 0 (GTP-Binding Protein alpha Subunits); 0 (Gnat1 protein, mouse); 147336-22-9 (Green Fluorescent Proteins); EC 3.6.5.1 (Transducin)
[Em] Mês de entrada:1711
[Cu] Atualização por classe:171113
[Lr] Data última revisão:
171113
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:161030
[St] Status:MEDLINE



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