Tissue transglutaminase-dependent posttranslational modification of the retinoblastoma gene product in promonocytic cells undergoing apoptosis
Tissue transglutaminase-dependent posttranslational modification of the retinoblastoma gene product in promonocytic cells undergoing apoptosis
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DOI：
10.1128/mcb.17.10.6040
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发表时间：
1997-10-01
影响因子：
5.3
通讯作者：
Piacentini, M
中科院分区：
文献类型：
--
作者：
Oliverio, S;Amendola, A;Piacentini, M
视网膜母细胞瘤基因产物(复审委员会)起着重要的作用在控制细胞释放的G(1)阶段和细胞凋亡,我们在这里显示,在细胞凋亡的早期阶段,复审委员会是由一个组织转谷氨酰胺酶转译后的修改(tTG)催化zed反应,事实上,利用小说haptenized裂解合成基质使得glutaminyl-tTG基质体内的隔离,我们确定了复审委员会作为一个潜在的tTG衬底U937细胞发生凋亡,与这一发现一致，我们发现U937细胞凋亡的特点是分子量为105,000至110,000的pRB形式迅速消失，同时出现分子量大于250,000的免疫反应产物涂片。通过将外源性纯化的tTG添加到活的U937细胞提取物中，pRB分子量的变化可以重现，并被丹西尸碱（一种有效的酶抑制剂）阻止。通过检测E2F-1水平和从U937细胞中分离和鉴定pRB-null克隆，研究了pRB翻译后修饰在细胞凋亡过程中的作用。值得注意的是，在这些U937衍生的克隆中，pRB的缺乏使这些p53-null细胞对血清停药、calphostin C和神经酰胺诱导的细胞凋亡具有高度的抗性。可能在细胞死亡过程中扮演重要角色。
The retinoblastoma gene product (pRB) plays an important role in controlling both cell release from the G(1) phase and apoptosis, We show here that in the early phases of apoptosis, pRB is posttranslationally modified by a tissue transglutaminase (tTG)-catalyzed zed reaction, In fact, by employing a novel haptenized lysis synthetic substrate which allows the isolation of glutaminyl-tTG substrates in vivo, we identified pRB as a potential tTG substrate in U937 cells undergoing apoptosis, In keeping with this finding, we showed that apoptosis of U937 cells is characterized by the rapid disappearance of the 105,000- to 110,000-molecular-weight pRB forms concomitantly with the appearance of a smear of immunoreactive products with a molecular weight of greater than 250,000, The shift in pRB molecular weight was reproduced by adding exogenous purified tTG to extracts obtained from viable U937 cells and was prevented by dansylcadaverine, a potent enzyme inhibitor. The effect of the pRB posttranslational modification during apoptosis was investigated by determining the E2F-1 levels and by isolating and characterizing pRB-null clones from U937 cells, Notably, the lack of pRB in these U937-derived clones renders these p53-null cells highly resistant to apoptosis induced by serum withdrawal, calphostin C, and ceramide, Taken together, these data suggest that tTG, acting on the PRE protein, might play an important role in the cell progression through the death program.