Inhibition of apoptosis and clonogenic survival of cells expressing crmA variants: optimal caspase substrates are not necessarily optimal inhibitors
Inhibition of apoptosis and clonogenic survival of cells expressing crmA variants: optimal caspase substrates are not necessarily optimal inhibitors
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DOI：
10.1093/emboj/18.2.330
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发表时间：
1999-01-15
期刊：
影响因子：
11.4
通讯作者：
Vaux, DL
中科院分区：
文献类型：
--
作者：
Ekert, PG;Silke, J;Vaux, DL
为了研究不同的caspase在细胞凋亡过程中的作用，我们设计了一系列基于牛痘病毒细胞因子反应调节因子A（crmA）蛋白的caspase抑制剂。野生型crmA抑制半胱天冬酶1和8，从而保护细胞免于由CD95或肿瘤坏死因子（TNF）受体连接引发的凋亡，但它不能保护细胞免于由其他半胱天冬酶介导的死亡。通过将crmA（LVAD）的四肽假底物区域替换为对于不同家族的半胱天冬酶是最佳底物的四肽，或者替换为来自杆状病毒蛋白p35（DQMD）的切割位点的四个残基，我们已经产生了一个家族的半胱天冬酶抑制剂，其显示出改变的保护免于细胞死亡的能力。尽管DEVD是半胱天冬酶3的最佳底物，但crmA DEVD降解迅速，并且是比不降解的crmA DQMD更弱的抑制剂。与野生型crmA和crmA DEVD不同，crmA DQMD能够抑制由半胱天冬酶3直接激活引起的凋亡，并保护淋巴细胞免于辐射和地塞米松诱导的死亡。
To study the role of various caspases during apoptosis, we have designed a series of caspase inhibitors based on the cowpox virus cytokine response modifier A (crmA) protein. Wild-type crmA inhibits caspases 1 and 8 and thereby protects cells from apoptosis triggered by ligation of CD95 or tumour necrosis factor (TNF) receptors, but it does not protect against death mediated by other caspases. By replacing the tetrapeptide pseudosubstrate region of crmA (LVAD) with tetrapeptides that are optimal substrates for the different families of caspases, or with the four residues from the cleavage site of the baculovirus protein p35 (DQMD), we have generated a family of caspase inhibitors that show altered ability to protect against cell death. Although DEVD is the optimal substrate for caspase 3, crmA DEVD was degraded rapidly and was a weaker inhibitor than crmA DQMD, which was not degraded. Unlike wild-type crmA and crmA DEVD, crmA DQMD was able to inhibit apoptosis caused by direct activation of caspase 3 and protected lymphoid cells from death induced by radiation and dexamethasone, Significantly, the protected cells were capable of sustained growth.