Tumor necrosis factor (TNF)-α-induced repression of GKAP42 protein levels through cGMP-dependent kinase (cGK)-Iα causes insulin resistance in 3T3-L1 adipocytes.
J Biol Chem
; 290(9): 5881-92, 2015 Feb 27.
Article
em En
| MEDLINE
| ID: mdl-25586176
ABSTRACT
Insulin receptor substrates (IRSs) have been shown to be major mediators of insulin signaling. Recently, we found that IRSs form high-molecular weight complexes, and here, we identify by yeast two-hybrid screening a novel IRS-1-associated protein a 42-kDa cGMP-dependent protein kinase-anchoring protein (GKAP42). GKAP42 knockdown in 3T3-L1 adipocytes suppressed insulin-dependent IRS-1 tyrosine phosphorylation and downstream signaling, resulting in suppression of GLUT4 translocation to plasma membrane induced by insulin. In addition, GLUT4 translocation was also suppressed in cells overexpressing GKAP42-N (the IRS-1 binding region of GKAP42), which competed with GKAP42 for IRS-1, indicating that GKAP42 binding to IRS-1 is required for insulin-induced GLUT4 translocation. Long term treatment of 3T3-L1 adipocytes with TNF-α, which induced insulin resistance, significantly decreased the GKAP42 protein level. We then investigated the roles of cGMP-dependent kinase (cGK)-Iα, which bound to GKAP42, in these changes. cGK-Iα knockdown partially rescued TNF-α-induced decrease in GKAP42 and impairment of insulin signals. These data indicated that TNF-α-induced repression of GKAP42 via cGK-Iα caused reduction of insulin-induced IRS-1 tyrosine phosphorylation at least in part. The present study describes analysis of the novel TNF-α-induced pathway, cGK-Iα-GKAP42, which regulates insulin-dependent signals and GLUT4 translocation.
Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Fator de Necrose Tumoral alfa
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Adipócitos
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Proteínas Adaptadoras de Transdução de Sinal
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Proteína Quinase Dependente de GMP Cíclico Tipo I
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Insulina
Tipo de estudo:
Etiology_studies
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Prognostic_studies
Limite:
Animals
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Humans
Idioma:
En
Ano de publicação:
2015
Tipo de documento:
Article