The activation of phosphoinositide 3-hydroxykinase (P13K) is currently believed to represent the critical regulatory event which leads to the production of a novel intracellular signal. We have examined the control of this pathway by a number of cell-surface receptors in NG115-401L-C3 neuronal cells. Insulin-like growth factor-I stimulated the accumulation of 3-phosphorylated inositol lipids in intact cells and the appearance of P13K in antiphosphotyrosine-antibody-directed immunoprecipitates prepared from lysed cells, suggesting that P13K had been activated by a mechanism involving a protein tyrosine kinase. In contrast, P13K in these cells was not regulated by a variety of G-protein-coupled receptors, nerve growth factor acting via a low affinity receptor, or receptors for transforming growth factor-beta and interleukin-1. The receptor-specificity of P13K activation in these cells places significant constraints on the possible physiological function(s) of this pathway.
Receptor regulation of phosphoinositide 3-hydroxykinase in the NG115-401L-C3 neuronal cell line: stimulation by insulin-like growth factor-I
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D R Poyner, M R Hanley, T R Jackson, P T Hawkins; Receptor regulation of phosphoinositide 3-hydroxykinase in the NG115-401L-C3 neuronal cell line: stimulation by insulin-like growth factor-I. Biochem J 15 March 1993; 290 (3): 901–905. doi: https://doi.org/10.1042/bj2900901
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