engleski

The activation of nuclear phosphoinositide 3- kinase C2β in all-trans-retinoic acid- differentiated HL-60 cells

The activity of nuclear phosphoinositide 3-kinase C2beta (PI3K-C2beta) was investigated in HL-60 cells induced to differentiate along granulocytic or monocytic lineages. A significant increase in the activity of immunoprecipitated PI3K-C2beta was observed in the nuclei and nuclear envelopes isolated from all-trans-retinoic acid (ATRA)- differentiated cells which was inhibited by the presence of PI3K inhibitor LY 294002. High- performance liquid chromatography analysis of inositol lipids showed an increased incorporation of radiolabelled phosphate in both PtdIns(3)P and PtdIns(3, 4, 5)P_3 with no changes in the levels of PtdIns(4)P, PtdIns(3, 4)P_2 and PtdIns(4, 5)P_2. Western blot analysis of the PI3K-C2beta immunoprecipitates with anti-P-Tyr antibody revealed a significant increase in the level of the immunoreactive band corresponding to PI3K- C2beta in the nuclei and nuclear envelopes isolated from ATRA-differentiated cells.

phosphoinositide 3-kinase C2beta ; nucleus ; HL-60 cell ; all-trans-retinoic acid ; tyrosine phosphorylation

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