Phosphorylation of β-actin by protein kinase C-delta in camptothecin analog-induced leukemic cell apoptosis

• 来源期刊: 中国药理学报（英文版）
• 关键词: leukemia apoptosis proteomics β-actin phosphorylation PKCδ
• 年，卷（期）: 2008,（1）
• 页码范围: 135-142
• 页数: 8页
• 语种: 英文
• DOI: 10.1111/j.1745-7254.2008.00753.x

摘要

Aim: This study was conducted to reveal new proteins involved in acute myeloid leukemia (AML) cell apoptosis. Methods: Using camptothecin analog NSC606985-induced leukemic U937 cell apoptosis as a model, this study performed a differen-tial proteomic analysis during apoptosis induction. The significantly modulated protein was underwent further investigation in the apoptotic process. Results: We found that β-actin protein presented two different spots on the two-dimen-sional electrophoresis (2-DE) map, which shared similar molecular weight and different pI. Those two spots demonstrated contrary changes (disappeared on the basic-end and increased on the acid-end spot) during apoptosis induction, although the total level of β-actin kept constant. This observation was further confirmed by immunoblot analysis on 2-DE gel. When NSC606985-treated cell iysate was incubated with alkaline phosphotase, β-actin on the basic-end spot was restored, indicating increased phosphorylation of β-actin during NSC606985-induced apoptosis. Moreover, the polymerization of actin also decreased after NSC606985 treatment. The increased β-actin phosphorylation and decreased ac-tin polymerization was antagonized by pre-treatment of rottlerin, a specific protein kinase C-delta (PKCδ) inhibitor. Conclusion: All these results indicate that β-actin was phosphorylated during apoptosis induction, which was mediated by acti-vated PKCδ.