Phospholipid activation of the insulin receptor kinase: regulation by phosphatidylinositol.
FASEB J
; 1(1): 55-9, 1987 Jul.
Article
en En
| MEDLINE
| ID: mdl-3038645
ABSTRACT
A soybean phospholipid mixture produced a concentration-dependent enhancement of beta subunit autophosphorylation of the detergent-soluble, purified human placental insulin receptor. Although phosphatidylcholine, phosphatidylethanolamine, or phosphatidylserine also increased insulin receptor autophosphorylation, only phosphatidylinositol (PtdIns) stimulated to a similar extent as the phospholipid mixture. The effect of PtdIns was biphasic, stimulating at low concentrations (75 microM), but having no stimulatory effect at high concentrations (1.0 mM). Phospholipids also stimulated the exogenous protein kinase activity of the insulin receptor toward histone H2B. Phosphorylation of PtdIns occurred with these purified insulin receptor preparations, but this activity was insulin-independent, and the turnover number for PtdIns phosphorylation in the presence of soybean phospholipid was 1/220th as small as the turnover number for the autophosphorylating activity. These results suggest that although PtdIns can modulate the activity of the insulin receptor kinase, PtdIns phosphorylation itself is not directly involved in this regulation.
Buscar en Google
Colección:
01-internacional
Banco de datos:
MEDLINE
Asunto principal:
Fosfatidilinositoles
/
Proteínas Tirosina Quinasas
/
Receptor de Insulina
Límite:
Humans
Idioma:
En
Revista:
FASEB J
Asunto de la revista:
BIOLOGIA
/
FISIOLOGIA
Año:
1987
Tipo del documento:
Article