Insulin induces expression of adenosine kinase gene in rat lymphocytes by signaling through the mitogen-activated protein kinase pathway
| Autor: | Monika Sakowicz, Miroslawa Szczepanska-Konkel, Tadeusz Pawelczyk, Marzena Podgorska |
|---|---|
| Rok vydání: | 2003 |
| Předmět: |
medicine.medical_specialty
MAP Kinase Signaling System Proto-Oncogene Proteins c-jun medicine.medical_treatment Molecular Sequence Data Culture Media Serum-Free Gene Expression Regulation Enzymologic Diabetes Mellitus Experimental Wortmannin chemistry.chemical_compound Proto-Oncogene Proteins Internal medicine medicine Animals Insulin Lymphocytes Enzyme Inhibitors Protein kinase A Adenosine Kinase Cells Cultured ets-Domain Protein Elk-1 Protein Synthesis Inhibitors Sirolimus biology Kinase c-jun Tyrosine phosphorylation Cell Biology Molecular biology IRS2 Rats Androstadienes DNA-Binding Proteins Insulin receptor Endocrinology Bucladesine chemistry Dactinomycin biology.protein Proto-Oncogene Proteins c-fos Spleen Transcription Factors |
| Zdroj: | Experimental Cell Research. 286:152-163 |
| ISSN: | 0014-4827 |
| DOI: | 10.1016/s0014-4827(03)00090-9 |
| Popis: | The activity of adenosine kinase (AK) was significantly impaired in splenocytes isolated from diabetic rats. Administration of insulin to diabetic animals restored AK activity, protein, and mRNA levels in diabetic splenocytes. Experiments performed on cultured rat lymphocytes demonstrated that insulin did not change the stability of AK mRNA. Insulin induced AK gene expression in a dose- and time-dependent manner. Maximal increases in AK mRNA (3.9-fold) and activity level (3.7-fold) were observed at the fourth and fifth hours of cell incubation with 10 nM insulin, respectively. The insulin effect on AK expression was not influenced by dibutyryl cAMP (dcAMP). On the other hand dcAMP weakly increased (1.7-fold) basal expression of AK. Exposure of rat lymphocytes to wortmannin, an inhibitor of phosphatidylinositol 3-kinase (PI3K), or rapamycin, an inhibitor of mTOR, did not affect the ability of insulin to stimulate expression of AK. Prior treatment of the cells with 10 microM PD98059, an inhibitor of mitogen-activated protein kinase (MAPK) kinase (MEK) completely blocked insulin-stimulated expression of AK gene. Insulin produced a significant transient increase in the tyrosine phosphorylation of ERK1/2, and PD98059 inhibited this phosphorylation. Furthermore exposure of cells to insulin has resulted in transient phosphorylation of Elk-1 on Ser-383 and sustained elevation of c-Jun and c-Fos protein. The maximal phosphorylation of Elk-1 was observed at 15 min, and was blocked by PD98059. We concluded that insulin stimulates AK gene expression through a series of events occurring sequentially. This includes activation of the MAPK cascade and subsequent phosphorylation of Elk-1 followed by increased expression of c-fos and c-jun genes. |
| Databáze: | OpenAIRE |
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