Insulin signaling to generate inositol phosphoglycans (IPGs) was demonstrated to occur via the participation of the heterotrimeric G-proteins Gq/11. IPGs were measured as two specific inositol markers, myo-inositol and chiro-inositol after strong acid hydrolysis. Insulin and Pasteurella multocida toxin (PMT) generated both myo-inositol and chiro-inositol IPGs in a dose-dependent manner. PMT has been shown to activate Gq specifically. Insulin action was abrogated by pre-treatment with anti Gq/11 antibody. Western blotting demonstrated the enrichment of both insulin receptor β subunit and Gq/11 in the liver membrane vesicles. Vesicles also contained clathrin, caveolin PLC β1 and PLCΔ. Immunogold staining revealed the co-localization of both insulin receptor β subunit and Gq/11 in an approximate stochiometric ratio of 1:3. No vesicles were detected with either component alone. The present and considerable published data provide strong evidence for insulin signaling both via a tyrosine kinase cascade mechanism and via heterotrimeric G-protein interactions.
|Original language||English (US)|
|Number of pages||9|
|Journal||Biochemical and Biophysical Research Communications|
|State||Published - 2002|
ASJC Scopus subject areas
- Molecular Biology
- Cell Biology