Activation of hPAK65 by caspase cleavage induces some of the morphological and biochemical changes of apoptosis
Activation of hPAK65 by caspase cleavage induces some of the morphological and biochemical changes of apoptosis
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DOI：
10.1073/pnas.94.25.13642
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发表时间：
1997-12-09
影响因子：
11.1
通讯作者：
Williams, LT
中科院分区：
文献类型：
--
作者：
Lee, N;MacDonald, H;Williams, LT
细胞凋亡是一种高度调控的细胞死亡形式，其特征在于细胞收缩和核浓缩等独特特征。hPAK 65是一种p21激活的激酶，其蛋白水解激活可诱导细胞形态学改变和诱导细胞凋亡。hPAK 65在体外和体内均被半胱天冬酶切割，切割位点位于N端调节p21结合结构域和C端激酶结构域之间。C-末端裂解产物被激活，其动力学特征与凋亡期间的半胱天冬酶激活平行。该C-末端hPAK 65片段还在体内激活c-Jun N-末端激酶途径。显微注射或转染该截短的hPAK 65引起细胞和核形态的显著改变，其随后促进CHO和Hela细胞中的apr，上睑下垂。相反，在表达显性阴性形式的hPAK 65的细胞中，凋亡被延迟。这些发现提供了直接证据，即由半胱天冬酶切割产生的活化形式的hPAK 65是介导凋亡中观察到的形态学和生化变化的促凋亡效应物。
Apoptosis is a highly regulated form of cell death, characterized by distinctive features such as cellular shrinkage and nuclear condensation. We demonstrate here that proteolytic activation of hPAK65, a p21-activated kinase, induces morphological changes and elicits apoptosis, hPAK65 is cleaved both in vitro and irt vivo by caspases at a single site between the N-terminal regulatory p21-binding domain and the C-terminal kinase domain. The C-terminal cleavage product becomes activated, with a kinetic profile that parallels caspase activation during apoptosis, This C-terminal hPAK65 fragment also activates the c-Jun N-terminal kinase pathway in vivo. Microinjection or transfection of this truncated hPAK65 causes striking alterations in cellular and nuclear morphology, which subsequently promotes apr,ptosis in both CHO and Hela cells. Conversely, apoptosis is delayed in cells expressing a dominant-negative form of hPAK65, These findings provide a direct evidence that the activated form of hPAK65 generated by caspase cleavage is a proapoptotic effector that mediates morphological and biochemical changes seen in apoptosis.