Potential Contribution of Translational Factors to Triiodo-L-Thyronine-Induced Insulin Synthesis by Pancreatic Beta Cells

dc.creatorGoulart-Silva, Francemilson
dc.creatorTeixeira, Silvania da Silva
dc.creatorLuchessi, Augusto Ducati
dc.creatorBichara dos Santos, Laila Romagueira
dc.creatorRebelato, Eduardo
dc.creatorCarpinelli, Angelo Rafael
dc.creatorNunes, Maria Tereza
dc.date2012
dc.date2013-09-19T18:06:47Z
dc.date2013-09-19T18:06:47Z
dc.date.accessioned2018-03-28T20:27:22Z
dc.date.available2018-03-28T20:27:22Z
dc.identifierThyroid. Mary Ann Liebert Inc, v.22, n.6, p.637-642, 2012
dc.identifier1050-7256
dc.identifierWOS:000305001200013
dc.identifier10.1089/thy.2011.0252
dc.identifierhttp://www.repositorio.unicamp.br/jspui/handle/REPOSIP/2403
dc.identifier.urihttp://repositorioslatinoamericanos.uchile.cl/handle/2250/1230186
dc.descriptionFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
dc.descriptionBackground: Thyroid hormones (THs) are known to regulate protein synthesis by acting at the transcriptional level and inducing the expression of many genes. However, little is known about their role in protein expression at the post-transcriptional level, even though studies have shown enhancement of protein synthesis associated with mTOR/p70S6K activation after triiodo-l-thyronine (T3) administration. On the other hand, the effects of TH on translation initiation and polypeptidic chain elongation factors, being essential for activating protein synthesis, have been poorly explored. Therefore, considering that preliminary studies from our laboratory have demonstrated an increase in insulin content in INS-1E cells in response to T3 treatment, the aim of the present study was to investigate if proteins of translational nature might be involved in this effect. Methods: INS-1E cells were maintained in the presence or absence of T3 (10(-6) or 10(-8) M) for 12 hours. Thereafter, insulin concentration in the culture medium was determined by radioimmunoassay, and the cells were processed for Western blot detection of insulin, eukaryotic initiation factor 2 (eIF2), p-eIF2, eIF5A, EF1A, eIF4E binding protein (4E-BP), p-4E-BP, p70S6K, and p-p70S6K. Results: It was found that, in parallel with increased insulin generation, T3 induced p70S6K phosphorylation and the expression of the translational factors eIF2, eIF5A, and eukaryotic elongation factor 1 alpha (eEF1A). In contrast, total and phosphorylated 4E-BP, as well as total p70S6K and p-eIF2 content, remained unchanged after T3 treatment. Conclusions: Considering that (i) p70S6K induces S6 phosphorylation of the 40S ribosomal subunit, an essential condition for protein synthesis; (ii) eIF2 is essential for the initiation of messenger RNA translation process; and (iii) eIF5A and eEF1A play a central role in the elongation of the polypeptidic chain during the transcripts decoding, the data presented here lead us to suppose that a part of T3-induced insulin expression in INS-1E cells depends on the protein synthesis activation at the post-transcriptional level, as these proteins of the translational machinery were shown to be regulated by T3.
dc.description22
dc.description6
dc.description637
dc.description642
dc.descriptionFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
dc.descriptionFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
dc.languageeng
dc.publisherMary Ann Liebert Inc
dc.publisherNew Rochelle
dc.relationThyroid
dc.rightsfechado
dc.sourceWOS
dc.subjectPROTEIN-SYNTHESIS
dc.subjectELONGATION
dc.subjectEXPRESSION
dc.subjectINITIATION
dc.subjectINHIBITION
dc.subjectMETABOLISM
dc.subjectSECRETION
dc.subjectRIBOSOME
dc.subjectBINDING
dc.subjectEIF2
dc.titlePotential Contribution of Translational Factors to Triiodo-L-Thyronine-Induced Insulin Synthesis by Pancreatic Beta Cells
dc.typeArtículos de revistas


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