Activation of protein kinase B (Akt/RAC‐protein kinase) by cellular stress and its association with heat shock protein Hsp27

FEBS Letters

Takemura, Yukitoshi²  Kuroda, Shun'ichi¹  Tanaka, Motonari²  Konishi, Hiroaki¹  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

关键词: Protein kinase B;    Akt or RAC-protein kinase;    Oxidative stress;    Heat shock;    Heat shock protein;    Hsp27;    Hsp;    heat shock or stress protein;    PH domain;    pleckstrin homology domain;    PI 3-kinase;    phosphatidylinositol 3-kinase;    PKB;    protein kinase B;    PKC;    protein kinase C;   

DOI  :  10.1016/S0014-5793(97)00541-3

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Protein kinase B (PKB, also named as Akt or RAC-protein kinase), that is activated by cellular stress such as heat shock and hyperosmotic treatment, was revealed to be activated by oxidative stress and by chemical stressors of CdCl₂ and NaAsO₂ by measuring the activity of the enzyme immunoprecipitated from the transfected COS-7 cells. Upon stress treatment, a 30-kDa phosphoprotein was co-immunoprecipitated with PKB from the cells metabolic labeled with [³²P]orthophosphate. The phosphoprotein was identified as Hsp27, a small heat shock protein, by immunoblot analysis and co-immunoprecipitation. The association of Hsp27 was specific to PKB as the heat shock protein was not co-immunoprecipitated with other protein kinases such as protein kinase C and PKN. When the cells were treated with H₂O₂, PKB was activated gradually and the association of Hsp27 with PKB increased concurrently with the enhancement of PKB activity. In heat-shocked cells, activation of PKB and the association of Hsp27 were detected immediately after the treatment, and the association of the heat shock protein decreased while PKB kept stimulated activity when the cells were further incubated at 37°C. These results suggest that Hsp27 is involved in the activation process of PKB in the signal transduction pathway of various forms of stress.

【 授权许可】

Unknown