| Autor: |
Tomohito Shibata, Akira Takaguri, Kazuo Ichihara, Kumi Satoh |
| Jazyk: |
angličtina |
| Rok vydání: |
2013 |
| Předmět: |
|
| Zdroj: |
Journal of Pharmacological Sciences, Vol 122, Iss 2, Pp 93-102 (2013) |
| Druh dokumentu: |
article |
| ISSN: |
1347-8613 |
| DOI: |
10.1254/jphs.12270FP |
| Popis: |
AMP-activated protein kinase (AMPK) contributes to the acceleration of insulin signaling. However, the mechanism by which AMPK regulates insulin signaling remains unclear. Serine phosphorylation of insulin receptor substrate (IRS)-1 negatively regulates insulin signaling. Here we investigated the role of AMPK in serine phosphorylation of IRS-1 at 636/639 and 307, which is induced by tumor necrosis factor (TNF)-α in 3T3L1 adipocytes. We demonstrated that the AMPK activator 5-aminoimidazole-4-carboxamide-1-d-ribofuranoside (AICAR) significantly inhibited the TNF-α–induced serine phosphorylation of IRS-1 at 636/639 and 307 by suppression of extracellular signal–regulated kinase (ERK) phosphorylation but not c-Jun-NH2-terminal kinase (JNK) phosphorylation. In addition, AICAR stimulation resulted in enhanced interaction between ERK and MAP kinase phosphatase-4 (DUSP9/MKP-4) without affecting DUSP9/MPK4 mRNA synthesis. Moreover, intraperitoneal administration (0.25 g/kg) of AICAR to db/db mice improved blood glucose levels and inhibited the phosphorylation of ERK in adipose tissue. In conclusion, we propose a new mechanism in which AICAR suppresses TNF-α–induced serine phosphorylation of IRS-1 at 636/639 and 307 by enhancing the interaction between ERK and DUSP9/MKP-4. Taken together, these findings provide evidence that AMPK plays a crucial role in improving of type 2 diabetes. Keywords:: 3T3L1 adipocyte, AICAR, insulin receptor substrate (IRS)-1, DUSP9/MKP-4, insulin resistance |
| Databáze: |
Directory of Open Access Journals |
| Externí odkaz: |
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