AMP-activated protein kinase activation by adrenoceptors in L6 skeletal muscle cells: mediation by alpha1-adrenoceptors causing glucose uptake
| Autor: | Dana S, Hutchinson, Tore, Bengtsson |
|---|---|
| Rok vydání: | 2006 |
| Předmět: |
CHO Cells
AMP-Activated Protein Kinases Protein Serine-Threonine Kinases Ribonucleotides Aminoimidazole Carboxamide Rats Enzyme Activation Glucose Multienzyme Complexes Cricetinae Animals Humans Insulin Calcium Phosphorylation Receptors Adrenergic beta-1 Muscle Skeletal Protein Kinase C Acetyl-CoA Carboxylase |
| Zdroj: | Diabetes. 55(3) |
| ISSN: | 0012-1797 |
| Popis: | AMP-activated protein kinase (AMPK), which functions as a sensor of cellular energy homeostasis, was phosphorylated after norepinephrine stimulation in L6 skeletal muscle cells. This effect was mediated by alpha1-adrenoceptors, with no stimulatory effects due to interactions at alpha2- or beta-adrenoceptors. Alpha1-adrenoceptors are Gq-coupled receptors, and calcium but not phorbol esters could mimic the effect of alpha1-adrenergic stimulation; and we show that protein kinase C is not involved as an upstream signal to AMPK by alpha1-adrenergic stimulation and that the AMP-to-ATP ratio is unaltered after alpha1-adrenergic stimulation. We further show that glucose uptake mediated by alpha1- but not by beta-adrenoceptors can be inhibited by AMPK inhibition. Acetyl-CoA carboxylase (ACC) is phosphorylated at Ser218 by AMPK, and alpha1- but not beta-adrenoceptor stimulation results in phosphorylation of ACC at this residue. These results suggest a novel pathway where alpha1-adrenoceptor activation, independent of protein kinase C, leads to activation of AMPK in skeletal muscle, which contributes to alpha1-adrenoceptor-mediated increases in glucose uptake. |
| Databáze: | OpenAIRE |
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