Nuclear import of PKCδ is required for apoptosis:: identification of a novel nuclear import sequence
Nuclear import of PKCδ is required for apoptosis:: identification of a novel nuclear import sequence
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DOI：
10.1093/emboj/cdf606
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发表时间：
2002-11-15
期刊：
影响因子：
11.4
通讯作者：
Reyland, ME
中科院分区：
文献类型：
--
作者：
DeVries, TA;Neville, MC;Reyland, ME
我们以前已经表明，蛋白激酶C δ（PKC δ）是细胞依赖性凋亡所必需的。在这里，我们表明，PKC δ进口到依托泊苷处理的细胞的细胞核，细胞凋亡所需的核进口，它是由PKC δ的C-末端的核定位信号（NLS）介导的。PKC δ的半胱天冬酶切割位点的突变抑制凋亡细胞中的核积累，表明半胱天冬酶切割促进了这一过程。PKC δ催化片段（CF δ）在转染细胞中的表达导致核定位和凋亡。我们发现，PKC δ NLS是必需的全长PKC δ和CF δ的核进口，并驱动核定位的多聚体绿色荧光蛋白。CFdelta的NLS内的突变防止核积聚并阻断细胞凋亡。相反，激酶阴性催化片段（KN-CF delta）的核表达保护细胞免于依托泊苷诱导的凋亡。NLS的突变阻断了KN-CF delta保护免受依托泊苷诱导的细胞凋亡的能力。这些结果表明，PKC δ调节细胞凋亡途径启动所需的基本核事件。
We have shown previously that protein kinase Cdelta (PKCdelta) is required for mitochondrial-dependent apoptosis. Here we show that PKCdelta is imported into the nucleus of etoposide-treated cells, that nuclear import is required for apoptosis and that it is mediated by a nuclear localization signal (NLS) in the C-terminus of PKCdelta. Mutation of the caspase cleavage site of PKCdelta inhibits nuclear accumulation in apoptotic cells, indicating that caspase cleavage facilitates this process. Expression of the PKCdelta catalytic fragment (CFdelta) in transfected cells results in nuclear localization and apoptosis. We show that the PKCdelta NLS is required for nuclear import of both full-length PKCdelta and CFdelta, and drives nuclear localization of a multimeric green fluorescent protein. Mutations within the NLS of CFdelta prevent nuclear accumulation and block apoptosis. Conversely, nuclear expression of a kinase-negative catalytic fragment (KN-CFdelta) protects cells from etoposide-induced apoptosis. Mutation of the NLS blocks the ability of KN-CFdelta to protect against etoposide-induced apoptosis. These results indicate that PKCdelta regulates an essential nuclear event(s) that is required for initiation of the apoptotic pathway.