The restrictive proteolysis of alpha-fodrin to a 120 kDa fragment is not catalyzed by calpains during thymic apoptosis.
The restrictive proteolysis of alpha-fodrin to a 120 kDa fragment is not catalyzed by calpains during thymic apoptosis.
复制标题
在胸腺细胞凋亡过程中，钙蛋白酶不会催化 α-胞质蛋白限制性蛋白水解为 120 kDa 片段。
DOI：
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发表时间：
1997
期刊：
影响因子：
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通讯作者：
S. Tanuma
中科院分区：
文献类型：
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作者：
Z. Kouchi;T. Saido;H. Ohyama;H. Maruta;K. Suzuki;S. Tanuma
胞衬蛋白的α-亚基（240 kDa）被发现在体内和体外大鼠胸腺细胞凋亡过程中被选择性地消化为120 kDa的片段。该片段通过针对全长α-胞衬蛋白的抗体（Ab）检测，但不能通过μ-钙蛋白酶产生的150 kDa片段Ab的抗N-末端序列（GMMPR）或α-胞衬蛋白Ab的抗PEST序列检测。另一方面，基础水平的150 kDa的片段不断识别这三种抗体在细胞凋亡。在细胞凋亡过程中的120 kDa片段的生产不受钙蛋白酶抑制剂，如Ac-LLLnal和E-64 d的添加，尽管抑制的150 kDa片段的产生。当X射线照射的胸腺细胞在N-甲苯磺酰基-L-苯丙氨酰氯甲基酮（TPCK）存在下孵育时，120 kDa片段的产生和细胞凋亡均受到抑制。纯化的μ-和m-钙蛋白酶没有催化的120 kDa的片段从纯化的α-胞衬蛋白在体外形成。这些结果表明，不同的钙蛋白酶的蛋白酶参与的主要过程中的α-胞衬蛋白水解为120 kDa的片段在胸腺细胞凋亡。
The alpha-subunit (240 kDa) of fodrin was found to be digested selectively to a 120 kDa fragment during apoptosis of rat thymocytes in vivo and in vitro. This fragment was detected by an antibody (Ab) against full length alpha-fodrin, but not by the anti-N-terminal sequence (GMMPR) of the mu-calpain-generated 150 kDa fragment Ab or the anti-PEST sequence of alpha-fodrin Ab. On the other hand, basal levels of the 150 kDa fragment were constantly recognized by these three antibodies during apoptosis. The production of the 120 kDa fragment during apoptosis was not affected by the addition of calpain inhibitors such as Ac-LLLnal and E-64d, despite inhibition of the generation of the 150 kDa fragment. When x-irradiated thymocytes were incubated in the presence of N-tosyl-L-phenylalanyl chloromethyl ketone (TPCK), both production of the 120 kDa fragment and apoptosis were suppressed. Purified mu- and m-calpain did not catalyze the formation of the 120 kDa fragment from purified alpha-fodrin in vitro. These results suggest that a protease different from calpains is involved in the major process of alpha-fodrin proteolysis to a 120 kDa fragment during thymic apoptosis.