Activation of phosphatidylinositol-3-kinase by insulin is mediated by both A and B human insulin receptor types.
Activation of a phosphatidylinositol-3-kinase (PI-3-kinase) is one of the earliest consequences of insulin binding to the receptor. The human insulin receptor exists in two isoforms which differ in the length of the alpha-subunit (HIR-A = 719 aa, HIR-B = 731 aa). To test whether both isoforms transduce an insulin signal on PI-3-kinase we used rat-1-fibroblasts expressing HIR-A or HIR-B. We found that insulin stimulates 32P incorporation into PIP through both HIR-A and HIR-B to a similar extent (approx. 8-10 fold).
Carrascosa
J M
JM
Institut für Diabetesforschung, München, Germany.
Vogt
B
B
Ullrich
A
A
Häring
H U
HU
D000818:Animals; D002478:Cells, Cultured; D004789:Enzyme Activation / Q000187:drug effects; D006801:Humans; D007328:Insulin / Q000494:pharmacology*; D007527:Isoenzymes / Q000378:metabolism; D019869:Phosphatidylinositol 3-Kinases; D010770:Phosphotransferases / Q000096:biosynthesis*; D051381:Rats; D011972:Receptor, Insulin / Q000187:drug effects / Q000378:metabolism*
D007328:Insulin; D007527:Isoenzymes; D010770:Phosphotransferases; D019869:Phosphatidylinositol 3-Kinases; D011972:Receptor, Insulin