Isolation of the active form of RAC‐protein kinase (PKB/Akt) from transfected COS‐7 cells treated with heat shock stress and effects of phosphatidylinositol 3,4,5‐trisphosphate and phosphatidylinositol 4,5‐bisphosphate on its enzyme activity

FEBS Letters

Ozaki, Shoichiro³  Kuroda, Shun'ichi¹  Watanabe, Yutaka³  Tanaka, Motonari²  Konishi, Hiroaki¹  Takenawa, Tadaomi⁴  Kikkawa, Ushio¹  Matsuzaki, Hidenori²  Ono, Yoshitaka² 

[1] Biosignal Research Center, Kobe University, Kobe 657, Japan;Department of Biology, Faculty of Science, Kobe University, Kobe 657, Japan;Department of Applied Chemistry, Faculty of Engineering, Ehime University, Matsuyama 790, Japan;Department of Biochemistry, Institute of Medical Science, University of Tokyo, Tokyo 113, Japan

关键词: RAC-protein kinase;    Phosphatidylinositol 3-kinase;    Stress;    Phosphatidylinositol 3;    4;    5-trisphosphate;    Phosphatidylinositol 4;    5-bisphosphate;    COS-7 cell;    PI 3-kinase;    phosphatidylinositol 3-kinase;    PtdIns(3)P;    phosphatidylinositol 3-phosphate;    PtdIns(3;    4)P2;    phosphatidylinositol 3;    4-bisphosphate;    PtdIns(3;    4;    5)P3;    phosphatidylinositol 3;    4;    5-trisphosphate;    PKC;    protein kinase C;    RAC-PK;    RAC-protein kinase;    PH domain;    pleckstrin homology domain;    PtdIns(4;    5)P2;    phosphatidylinositol 4;    5-bisphosphate;   

DOI  :  10.1016/0014-5793(96)01120-9

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

RAC-protein kinase (PKB/Akt) has been shown to be activated by growth factor stimulation as a downstream target of phosphatidylinositol 3-kinase and also by heat shock through a pathway independent of phosphatidylinositol 3-kinase. RAC-protein kinase was purified by antibody affinity chromatography from COS-7 cells transfected with the epitope-tagged expression plasmid. The protein kinase activity of RAC-protein kinase purified from heat-treated cells was 9-fold higher than the enzyme isolated from untreated control cells. Phosphatidylinositol 3,4,5-trisphosphate did not enhance the activity of RAC-protein kinase purified from either heat-treated cells or control cells, whereas phosphatidylinositol 4,5-bisphosphate suppressed the enzyme isolated from heat-treated cells. These results indicate that RAC-protein kinase may interact with phosphoinositides, however, it could not be activated by simple association with the product of phosphatidylinositol 3-kinase reaction.

【 授权许可】

Unknown