Back to Search
Start Over
Phosphatidylinositol 3-kinase translocates onto liver endoplasmic reticulum and may account for the inhibition of glucose-6-phosphatase during refeeding
- Source :
- The Journal of biological chemistry. 274(6)
- Publication Year :
- 1999
-
Abstract
- By using a rapid procedure of isolation of microsomes, we have shown that the liver glucose-6-phosphatase activity was lowered by about 30% (p0.001) after refeeding for 360 min rats previously unfed for 48 h, whereas the amount of glucose-6-phosphatase protein was not lowered during the same time. The amount of the regulatory subunit (p85) and the catalytic activity of phosphatidylinositol 3-kinase (PI3K) were higher by a factor of 2.6 and 2.4, respectively (p0.01), in microsomes from refed as compared with fasted rats. This resulted from a translocation process because the total amount of p85 was the same in the whole liver homogenates from fasted and refed rats. The amount of insulin receptor substrate 1 (IRS1) was also higher by a factor of 2.6 in microsomes from refed rats (p0. 01). Microsome-bound IRS1 was only detected in p85 immunoprecipitates. These results strongly suggest that an insulin-triggered mechanism of translocation of PI3K onto microsomes occurs in the liver of rats during refeeding. This process, via the lipid products of PI3K, which are potent inhibitors of glucose-6-phosphatase (Mithieux, G., Danièle, N., Payrastre, B., and Zitoun, C. (1998) J. Biol. Chem. 273, 17-19), may account for the inhibition of the enzyme and participate to the inhibition of hepatic glucose production occurring in this situation.
- Subjects :
- Male
Biology
Endoplasmic Reticulum
Biochemistry
Rats, Sprague-Dawley
chemistry.chemical_compound
Mice
Phosphatidylinositol 3-Kinases
Adipocytes
Animals
Phosphatidylinositol
Amino Acid Sequence
Molecular Biology
Kinase
Endoplasmic reticulum
Biological Transport
Cell Biology
Rats
chemistry
Liver
Food
Microsome
biology.protein
Glucose-6-Phosphatase
Microsomes, Liver
Glucose 6-phosphatase
Subjects
Details
- ISSN :
- 00219258
- Volume :
- 274
- Issue :
- 6
- Database :
- OpenAIRE
- Journal :
- The Journal of biological chemistry
- Accession number :
- edsair.doi.dedup.....609487c8517b2e5d5f22e98e7c19e5d0