Protein kinase Cδ regulates apoptosis via activation of STAT1
Protein kinase Cδ regulates apoptosis via activation of STAT1
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DOI：
10.1074/jbc.m407448200
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发表时间：
2004-10-29
影响因子：
4.8
通讯作者：
Reyland, ME
中科院分区：
文献类型：
--
作者：
DeVries, TA;Kalkofen, RL;Reyland, ME
蛋白激酶C δ（PKC δ）是细胞凋亡所必需的，但目前对PKC δ下游效应子的研究还不多。在这里，我们表明，STAT 1的激活是对DNA损伤的早期反应，STAT 1的激活需要PKC δ。用依托泊苷处理HeLa细胞导致Ser（727）上的STAT 1磷酸化以及STAT 1与PKC δ的缔合。依托泊苷增加STAT 1依赖性报告基因的转录。增加的转录以及STAT 1 Ser（727）磷酸化可以通过抑制或消耗PKC δ来阻断。为了研究STAT 1是否是PKC δ介导的细胞凋亡所必需的，我们利用了U3 A STAT 1缺陷细胞。PKC δ诱导的细胞凋亡在U3 A细胞中受到抑制，但可以通过与STAT 1 α共转染而不是与Ser（727）突变的STAT 1共转染来挽救。用依托泊苷处理后30-60分钟，可检测到STAT 1、磷酸化Ser（727）STAT 1和PKC δ的核积聚。细胞核定位是细胞凋亡所必需的，因为PKC δ的细胞核定位突变体在用STAT 1 α重建的U3 A细胞中不诱导细胞凋亡，并且STAT 1的细胞核定位突变体不支持PKC δ诱导的U3 A细胞凋亡。我们的数据确定STAT 1作为PKC δ的下游靶点，并表明PKC δ可能通过激活STAT 1靶基因来调节细胞凋亡。
Protein kinase Cdelta(PKCdelta) is required for mitochondria-dependent apoptosis; however, little is known about downstream effectors of PKCdelta in apoptotic cells. Here we show that activation of STAT1 is an early response to DNA damage and that STAT1 activation requires PKCdelta. Treatment of HeLa cells with etoposide results in phosphorylation of STAT1 on Ser(727) and the association of STAT1 with PKCdelta. Etoposide increases transcription from STAT1-dependent reporter constructs. Increased transcription, as well as STAT1 Ser(727) phosphorylation, can be blocked by inhibition or depletion of PKCdelta. To ask if STAT1 is required for PKCdelta-mediated apoptosis, we utilized U3A STAT1-deficient cells. Induction of apoptosis by PKCdelta is suppressed in U3A cells but can be rescued by co-transfection with STAT1alpha but not STAT1 mutated at Ser(727). Nuclear accumulation of STAT1, phospho-Ser(727) STAT1, and PKCdelta are detectable 30-60 min after treatment with etoposide. Nuclear localization is necessary for apoptosis, since a nuclear localization mutant of PKCdelta does not induce apoptosis in U3A cells reconstituted with STAT1alpha, and a nuclear localization mutant of STAT1 does not support PKCdelta-induced apoptosis in U3A cells. Our data identify STAT1 as a downstream target of PKCdelta and suggest that PKCdelta may regulate apoptosis by activation of STAT1 target genes.