Overexpression of peptidylarginine deiminase IV features in apoptosis of haematopoietic cells
Overexpression of peptidylarginine deiminase IV features in apoptosis of haematopoietic cells
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DOI：
10.1007/s10495-006-3715-4
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发表时间：
2006-02-01
期刊：
影响因子：
7.2
通讯作者：
Hung, HC
中科院分区：
文献类型：
--
作者：
Liu, GY;Liao, YF;Hung, HC
肽基精氨酸脱亚胺酶(PADI)通过翻译后修饰将肽基精氨酸转化为瓜氨酸。PADI4是该家族的成员之一，在免疫细胞分化和细胞死亡过程中发挥着重要作用。为了阐明PADI4在造血细胞死亡中的作用，我们研究了可诱导的PADI4过表达是否促进了细胞的凋亡。PADI4以剂量和时间依赖的方式降低人白血病HL-60细胞和人急性T白血病Jurkat细胞的存活率。通过核固缩、DNA片段化、亚G1期出现、线粒体膜电位丧失(Delta psi(M))、线粒体细胞色素c释放到细胞质以及caspase9和3的蛋白水解性激活来确定其诱导凋亡的活性。PADI4过表达后，细胞在进入凋亡性死亡之前显著地停滞在G1期。PADI4通过增加抑癌基因P53及其下游的P21来控制细胞周期。在蛋白表达和激酶活性检测中，除细胞周期蛋白D外，细胞周期蛋白依赖性蛋白依赖性蛋白激酶(CDKs)和细胞周期蛋白(Cyclins)的蛋白水平均不降低，而CDK2(G1期进入S期)和CDK1(G2期进入M期)的活性则被条件诱导的PADI4抑制。P53还扩增其下游的Bax，诱导线粒体释放细胞色素c。根据这些数据，我们认为PADI4主要通过细胞周期停滞和线粒体介导的途径诱导细胞凋亡。此外，PADI4通过增加细胞内p21来控制细胞周期，并通过Bax的积聚来降低Bcl-2功能，破坏Delta psi(M)，将细胞色素c释放到细胞质中，激活caspase级联，从而在PADI4诱导的细胞凋亡中发挥作用。
Peptidylarginine deiminases (PADIs) convert peptidylarginine into citrulline via posttranslational modification. One member of the family, PADI4, plays an important role in immune cell differentiation and cell death. To elucidate the participation of PADI4 in haematopoietic cell death, we examine whether inducible overexpression of PADI4 enhances the apoptotic cell death. PADI4 reduced the viability in a dose- and time-dependent manner of human leukemia HL-60 cells and human acute T leukemia Jurkat cells. The apoptosis-inducing activities were determined by nuclear condensation, DNA fragmentation, sub-G1 appearance, loss of mitochondrial membrane potential (Delta psi(m)), release of mitochondrial cytochrome c into cytoplasm and proteolytic activation of caspase 9 and 3. Following PADI4 overexpression, cells arrest in G1 phase significantly before their entrance into apoptotic cell death. PADI4 increases tumor suppressor p53 and its downstream p21 to control cell cycle. In the detections of protein expression and kinase activity, all protein levels of cyclin-dependent kinases (CDKs) and cyclins are not reduced except cyclin D, however, CDK2 (G1 entry S phase) and CDK1 (G2 entry M phase) enzyme activities are inhibited by conditionally inducible PADI4. p53 also expands its other downstream Bax to induce cytochrome c release from mitochondria. According to these data, we suggest that PADI4 induces apoptosis mainly through cell cycle arrest and mitochondria-mediated pathway. Furthermore, p53 features in PADI4-induced apoptosis by increasing intracellular p21 to control cell cycle and by Bax accumulation to decline Bcl-2 function, destroy Delta psi(m), release cytochrome c to cytoplasm and activate the caspase cascade.