Caspase activation of mammalian Sterile 20-like kinase 3 (Mst3) - Nuclear translocation and induction of apoptosis
Caspase activation of mammalian Sterile 20-like kinase 3 (Mst3) - Nuclear translocation and induction of apoptosis
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DOI：
10.1074/jbc.m202468200
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发表时间：
2002-09-13
影响因子：
4.8
通讯作者：
Yuan, CJ
中科院分区：
文献类型：
--
作者：
Huang, CYF;Wu, YM;Yuan, CJ
哺乳动物不育20样激酶3（Mst 3）是生殖中心激酶-III家族的成员，其生理功能尚不清楚。它在NH 2末端含有一个保守的激酶结构域，而在COOH末端有一个调节结构域。在这项研究中，我们证明，内源性Mst 3特异性裂解时，Jurkat细胞用抗Fas抗体或星形孢菌素，这种裂解是由半胱天冬酶抑制剂，Ac-DEVD-CHO抑制。使用凋亡Jurkat细胞提取物和重组半胱天冬酶，我们绘制了半胱天冬酶切割位点AETD（313），其位于NH 2-末端激酶结构域和COOH-末端调节结构域的连接处。半胱天冬酶介导的切割。Mst 3激活其内在激酶活性，表明Mst 3的COOH末端结构域负调控激酶结构域。此外，通过半胱天冬酶蛋白水解去除Mst 3 COOH-末端结构域促进核转位。野生型或COOH末端截短的Mst 3在细胞中的异位表达导致DNA片段化和凋亡特征的形态学变化。相比之下，无催化活性的Mst 3没有表现出这样的变化，暗示Mst 3激酶活性参与介导这些效应。总的来说，这些结果支持这样的概念，半胱天冬酶介导的蛋白水解激活Mst 3有助于细胞凋亡。
Mammalian Sterile 20-like kinase 3 (Mst3), the physiological functions of which are unknown, is a member of the germinal center kinase-III family. It contains a conserved kinase domain at its NH2 terminus, whereas there is a regulatory domain at its COOH terminus. In this study we demonstrate that endogenous Mst3 is specifically cleaved when Jurkat cells were treated with anti-Fas antibody or staurosporine and that this cleavage is inhibited by the caspase inhibitor, Ac-DEVD-CHO. Using apoptotic Jurkat cell extracts and recombinant caspases, we mapped the caspase cleavage site, AETD(313), which is at the junction of the NH2-terminal kinase domain and the COOH-terminal regulatory domain. Caspase-mediated cleavage of. Mst3 activates its intrinsic kinase activity, suggesting that the COOH-terminal domain of Mst3 negatively regulates the kinase domain. Furthermore, proteolytic removal of the Mst3 COOH-terminal domain by caspases promotes nuclear translocation. Ectopic expression of either wild-type or COOH-terminal truncated Mst3 in cells results in DNA fragmentation and morphological changes characteristic of apoptosis. By contrast, no such changes were exhibited for catalytically inactive Mst3, implicating the involvement of Mst3 kinase activity for mediation of these effects. Collectively, these results support the notion that caspase-mediated proteolytic activation of Mst3 contributes to apoptosis.