The temporal relationship between protein phosphatase, ICE/CED-3 proteases, intracellular acidification, and DNA fragmentation in apoptosis.
The temporal relationship between protein phosphatase, ICE/CED-3 proteases, intracellular acidification, and DNA fragmentation in apoptosis.
复制标题
细胞凋亡中蛋白磷酸酶、ICE/CED-3 蛋白酶、细胞内酸化和 DNA 碎片之间的时间关系。
DOI：
10.1006/excr.1996.3401
复制
发表时间：
1997
期刊：
影响因子：
--
通讯作者：
Eastman,A
中科院分区：
文献类型：
--
作者：
Wolf,CM;Reynolds,JE;Morana,SJ;Eastman,A
细胞凋亡发生在发育和组织稳态过程中，并在物理和化学应激的条件下。在细胞凋亡期间，细胞消化它们的DNA，降低细胞内pH，收缩，表现出蛋白磷酸酶活性，并激活ICE/CED-3蛋白酶家族的成员。该蛋白酶活性通过聚（ADP-核糖）聚合酶（PARP）的裂解来鉴定。细胞凋亡过程中的磷酸酶活性被观察为视网膜母细胞瘤易感蛋白（Rb）的去磷酸化。丝氨酸/苏氨酸磷酸酶抑制剂可以防止Rb的去磷酸化和细胞凋亡，这表明Rb去磷酸化是细胞凋亡的关键调节剂的指示。这里描述的实验旨在建立这些事件之间的时间关系。拓扑异构酶抑制剂依托泊苷可诱导人ML-1细胞凋亡。ICE/CED-3蛋白酶家族的抑制剂z-VAD-氟甲基酮（FMK）显示出对PARP裂解、细胞内酸化、DNA消化、膜通透性早期变化和细胞收缩的浓度依赖性保护，从而将所有这些事件置于ICE/CED-3蛋白酶作用的下游。然而，z-VAD-FMK没有阻止Rb的去磷酸化，将这种变化的上游的蛋白酶。这些结果表明，蛋白磷酸酶和激酶之间的不平衡，负责Rb的去磷酸化也负责ICE/CED-3蛋白酶的激活，这反过来又是负责所有其他事件与细胞凋亡。
Apoptosis occurs during development and tissue homeostasis, and under conditions of physical and chemical stress. During apoptosis, cells digest their DNA, decrease intracellular pH, shrink, exhibit protein phosphatase activity, and activate members of the ICE/CED-3 family of proteases. This protease activity is identified by cleavage of poly(ADP-ribose) polymerase (PARP). Phosphatase activity during apoptosis is observed as dephosphorylation of the retinoblastoma susceptibility protein (Rb). Serine/threonine phosphatase inhibitors can prevent dephosphorylation of Rb and apoptosis, suggesting that Rb dephosphorylation is an indication of a critical regulator of apoptosis. The experiments described here were designed to establish the temporal relationship between these events. Apoptosis was induced in human ML-1 cells by the topoisomerase inhibitor etoposide. An inhibitor of the ICE/CED-3 protease family, z-VAD-fluoromethylketone (FMK), showed concentration-dependent protection from PARP cleavage, intracellular acidification, DNA digestion, early changes in membrane permeability, and cell shrinkage, thereby placing all of these events downstream of the ICE/CED-3 protease action. However, z-VAD-FMK did not prevent the dephosphorylation of Rb, placing this change upstream of the protease. These results suggest that the imbalance between protein phosphatase and kinase that is responsible for the dephosphorylation of Rb is also responsible for the activation of ICE/CED-3 proteases, which in turn is responsible for all the other events associated with apoptosis.