Insulin-dependent phosphatidylinositol 3'-kinase activity co-precipitates with insulin receptor in human circulating mononuclear cells.
In order to establish a working cellular model for the study of post-receptor signaling events, insulin-dependent phosphatidylinositol 3' (PtdIns 3')-kinase activity was investigated in circulating mononuclear cells from normal subjects. The p85 alpha regulatory subunit of PtdIns 3'-kinase co-precipitated with activated insulin receptor as revealed by immunoblotting. Whereas insulin receptor substrate-1 was weakly detected, insulin increased 5.5 +/- 1.5-fold (mean +/- SD) PtdIns 3'-kinase activity in receptor immunoprecipitates. We conclude that insulin-stimulated PtdIns 3'-kinase activity is measurable in circulating mononuclear cells which may constitute an easily available cellular model for the detection of post-receptor defects in insulin-resistant states.
Renard
E
E
CRBM, INSERM U249/CNRS UPR 9008, University of Montpellier I, France.
Grigorescu
F
F
Lavabre
C
C
Kahn
C R
CR
D000328:Adult; D000595:Amino Acid Sequence; D006801:Humans; D007328:Insulin / Q000502:physiology; D055504:Insulin Receptor Substrate Proteins; D008969:Molecular Sequence Data; D009000:Monocytes / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D019869:Phosphatidylinositol 3-Kinases; D010750:Phosphoproteins / Q000378:metabolism; D010766:Phosphorylation; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000378:metabolism*; D011972:Receptor, Insulin / Q000378:metabolism*
C526292:IRS1 protein, human; D007328:Insulin; D055504:Insulin Receptor Substrate Proteins; D010750:Phosphoproteins; D019869:Phosphatidylinositol 3-Kinases; D017853:Phosphotransferases (Alcohol Group Acceptor); D011972:Receptor, Insulin