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Phospholipid activation of the insulin receptor kinase: regulation by phosphatidylinositol
Author(s) -
Sweet Laurel J.,
Dudley David T.,
Pessin Jeffrey E.,
Spector Arthur A.
Publication year - 1987
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.1.1.3038645
Subject(s) - autophosphorylation , phosphatidylinositol , insulin receptor , phosphatidylethanolamine , phospholipid , irs2 , phosphorylation , insulin , kinase , biochemistry , phosphatidylcholine , phosphatidylserine , chemistry , microbiology and biotechnology , biology , protein kinase a , endocrinology , insulin resistance , membrane
A soybean phospholipid mixture produced a concentration‐dependent enhancement of β 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 Ptdlns was biphasic, stimulating at low concentrations (75 μ m ), but having no stimulatory effect at high concentrations (1.0 m m ). 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.—S weet , L. J.; D udley , D. T.; P essin , J. E.; S pector , A. A. Phospholipid activation of the insulin receptor kinase: regulation by phosphatidyl‐inositol. FASEB J. 1: 55‐59; 1987.