Calcium-dependent, interleukin 1 beta-converting enzyme inhibitor-insensitive degradation of lamin B-1 and DNA fragmentation in isolated thymocyte nuclei
Calcium-dependent, interleukin 1 beta-converting enzyme inhibitor-insensitive degradation of lamin B-1 and DNA fragmentation in isolated thymocyte nuclei
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DOI：
10.1074/jbc.271.37.22398
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发表时间：
1996-09-13
影响因子：
4.8
通讯作者：
McConkey, DJ
中科院分区：
文献类型：
--
作者：
McConkey, DJ
最近的工作表明核纤层蛋白的蛋白水解降解是细胞凋亡中的常见事件，尽管涉及的蛋白酶的性质仍然不清楚。我们以前的工作表明，在糖皮质激素处理的胸腺细胞中，核纤层蛋白B-1的降解通过Ca 2+敏感机制发生，并且外源性Ca 2+促进未处理细胞的分离胸腺细胞核中的核纤层蛋白降解，在这里，我们证明了基于肽的半胱氨酸蛋白酶白细胞介素1 β转换酶家族抑制剂，（Tyr-Val-Ala-Asp氟甲基酮）和核支架多催化蛋白酶（Ala-Pro-Phe氯甲基酮）阻断用糖皮质激素处理的胸腺细胞中核纤层蛋白B-1降解为21-kDa片段，Ca 2+动员剂毒胡萝卜素或T细胞受体的抗体。然而，在一组对涉及凋亡的几种不同蛋白酶具有特异性的抑制剂中，只有甲苯磺酰基苯丙氨酰氯甲基酮和核支架蛋白酶抑制剂阻断核纤层蛋白降解，组蛋白H1切割，和DNA断裂。通过稳定转染在细胞核中过表达人BCL-2导致对Ca 2+刺激的核纤层蛋白降解和DNA片段化的抑制，表明内源性细胞核BCL-2调节细胞核支架蛋白酶的活化，结果表明，存在一个由常驻Ca 2 +-介导的核纤层蛋白降解和DNA片段化的替代途径。受刺激的核蛋白酶，不直接依赖于细胞死亡调节因子的白细胞介素1 β转化酶家族的激活。
Recent work suggests that the proteolytic degradation of the nuclear lamins is a common event in apoptosis, although the nature of the proteases involved is still not clear, Our previous work showed that the degradation of lamin B-1 in glucocorticoid-treated thymocytes occurs via a Ca2+-sensitive mechanism and that exogenous Ca2+ promotes lamin degradation in isolated thymocyte nuclei from untreated cells, Here we demonstrate that peptide-based inhibitors of the interleukin 1 beta-converting enzyme family of cysteine proteases (Tyr-Val-Ala-Asp fluoromethyl ketone) and of the nuclear scaffold multicatalytic proteinase (Ala-Pro-Phe chloromethyl ketone) block the degradation of lamin B-1 to a 21-kDa fragment in thymocytes treated with glucocorticoid, the Ca2+-mobilizing agent thapsigargin, or antibodies to the T cell receptor, However, among a panel of inhibitors specific for several different proteases implicated in apoptosis, only tosylphenylalanyl chloromethyl ketone and the nuclear scaffold protease inhibitor block lamin degradation, histone H1 cleavage, and DNA fragmentation in isolated thymocyte nuclei incubated with Ca2+. Overexpression of human BCL-2 in nuclei by stable transfection resulted in an inhibition of Ca2+-stimulated lamin degradation and DNA fragmentation, suggesting that endogenous nuclear BCL-2 regulates activation of the nuclear scaffold protease, The results demonstrate the existence of an alternative pathway of lamin degradation and DNA fragmentation mediated by a resident Ca2+-stimulated nuclear protease that is not directly dependent upon activation of the interleukin 1 beta-converting enzyme family of cell death regulators.