Open AccessPhosphorylation of β‐actin by protein kinase C‐delta in camptothecin analog‐induced leukemic cell apoptosis 1
Author(s) -
WANG Shuang,
ZHENG Ying,
YU Yun,
XIA Li,
CHEN Guoqiang,
YANG Yongzong,
WANG Lishun
Publication year - 2008
Publication title -
acta pharmacologica sinica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.514
H-Index - 90
eISSN - 1745-7254
pISSN - 1671-4083
DOI - 10.1111/j.1745-7254.2008.00753.x
Subject(s) - actin , apoptosis , microbiology and biotechnology , phosphorylation , biology , protein kinase c , cytochalasin d , chemistry , cell , biochemistry , cytoskeleton
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 differential 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‐dimensional 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 lysate 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 actin 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 activated PKCδ.