Stimulation of phospholipase C activity by insulin is mediated by both isotypes of the human insulin receptor.
The human insulin receptor exists in two isoforms, HIR-A and HIR-B. We studied whether both insulin receptor isotypes are able to mediate an insulin signal to phospholipase C. Plasma membranes were prepared from rat-1 fibroblasts transfected either with HIR-A or HIR-B and insulin stimulated PIP-hydrolysis was determined. We found that insulin stimulates PIP-hydrolysis in a similar dose dependent manner and to a similar extent in plasma membranes expressing HIR-A and HIR-B. These data suggest that both receptor isoforms are equally able to activate phospholipase-C.
Kellerer
M
M
Institut für Diabetesforschung, München, Germany.
Machicao
F
F
Seffer
E
E
Mushack
J
J
Ullrich
A
A
Häring
H U
HU
D000255:Adenosine Triphosphate / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000494:pharmacology; D002462:Cell Membrane / Q000201:enzymology; D005347:Fibroblasts / Q000201:enzymology; D006801:Humans; D007328:Insulin / Q000494:pharmacology*; D008345:Manganese / Q000494:pharmacology; D018129:Phosphatidylinositol Phosphates; D010716:Phosphatidylinositols / Q000378:metabolism; D051381:Rats; D011972:Receptor, Insulin / Q000235:genetics / Q000502:physiology*; D014162:Transfection; D010738:Type C Phospholipases / Q000378:metabolism*; D014638:Vanadates / Q000494:pharmacology
D007328:Insulin; D018129:Phosphatidylinositol Phosphates; D010716:Phosphatidylinositols; C037178:phosphatidylinositol 4-phosphate; D014638:Vanadates; D008345:Manganese; D000255:Adenosine Triphosphate; D011972:Receptor, Insulin; D010738:Type C Phospholipases; D002118:Calcium