Abstract
M2-type pyruvate kinase (M2-PK) mRNA is produced from the PKM gene by an alternative RNA splicing in adipocytes. We found that insulin increased the level of M2-PK mRNA in 3T3-L1 adipocytes in both time- and dose-dependent manners. This induction did not require the presence of glucose or glucosamine in the medium. The insulin effect was blocked by pharmacological inhibitors of insulin signaling pathways such as wortmannin, an inhibitor of phosphatidylinositol 3-kinase (PI3K), and PD98059, an inhibitor of mitogen-activated protein kinase (MAPK) kinase. A stable reporter expression assay showed that the promoter activity of an about 2.2-kb 5′-flanking region of the rat PKM gene was stimulated by insulin, but the extents of these stimulations were lower than those of the mRNA stimulation. Thus, we suggest that insulin increases the level of M2-PK mRNA in adipocytes by acting at transcriptional and post-transcriptional levels through signaling pathways involving both PI3K and MAPK kinase.
Original language | English |
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Pages (from-to) | 1272-1277 |
Number of pages | 6 |
Journal | Bioscience, Biotechnology and Biochemistry |
Volume | 67 |
Issue number | 6 |
DOIs | |
Publication status | Published - 1 Jan 2003 |
Externally published | Yes |
Keywords
- 3T3-L1 adipocytes
- Insulin
- Mitogen-activated protein kinase kinase
- Phosphatidylinositol 3-kinase
- Pyruvate kinase M gene
ASJC Scopus subject areas
- Analytical Chemistry
- Biotechnology
- Biochemistry
- Applied Microbiology and Biotechnology
- Molecular Biology
- Organic Chemistry