Differential Regulation of ERK1/2 and mTORC1 Through T1R1/T1R3 in MIN6 Cells.
Mol Endocrinol
; 29(8): 1114-22, 2015 Aug.
Article
em En
| MEDLINE
| ID: mdl-26168033
ABSTRACT
The MAPKs ERK1/2 respond to nutrients and other insulin secretagogues in pancreatic ß-cells and mediate nutrient-dependent insulin gene transcription. Nutrients also stimulate the mechanistic target of rapamycin complex 1 (mTORC1) to regulate protein synthesis. We showed previously that activation of both ERK1/2 and mTORC1 in the MIN6 pancreatic ß-cell-derived line by extracellular amino acids (AAs) is at least in part mediated by the heterodimeric T1R1/T1R3, a G protein-coupled receptor. We show here that AAs differentially activate these two signaling pathways in MIN6 cells. Pretreatment with pertussis toxin did not prevent the activation of either ERK1/2 or mTORC1 by AAs, indicating that G(I) is not central to either pathway. Although glucagon-like peptide 1, an agonist for a G(s-)coupled receptor, activated ERK1/2 well and mTORC1 to a small extent, AAs had no effect on cytosolic cAMP accumulation. Ca(2+) entry is required for ERK1/2 activation by AAs but is dispensable for AA activation of mTORC1. Pretreatment with UBO-QIC, a selective G(q) inhibitor, reduced the activation of ERK1/2 but had little effect on the activation of mTORC1 by AAs, suggesting a differential requirement for G(q). Inhibition of G(12/13) by the overexpression of the regulator of G protein signaling domain of p115 ρ-guanine nucleotide exchange factor had no effect on mTORC1 activation by AAs, suggesting that these G proteins are also not involved. We conclude that AAs regulate ERK1/2 and mTORC1 through distinct signaling pathways.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Transdução de Sinais
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Proteína Quinase 1 Ativada por Mitógeno
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Receptores Acoplados a Proteínas G
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Complexos Multiproteicos
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Proteína Quinase 3 Ativada por Mitógeno
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Serina-Treonina Quinases TOR
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Aminoácidos
Limite:
Animals
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Humans
Idioma:
En
Revista:
Mol Endocrinol
Ano de publicação:
2015
Tipo de documento:
Article