Mitochondrial PKCε and MAPK form signaling modules in the murine heart -: Enhanced mitochondrial PKCε-MAPK interactions and differential MAPK activation in PKCε-induced cardioprotection
Mitochondrial PKCε and MAPK form signaling modules in the murine heart -: Enhanced mitochondrial PKCε-MAPK interactions and differential MAPK activation in PKCε-induced cardioprotection
复制标题
DOI：
10.1161/01.res.0000012702.90501.8d
复制
发表时间：
2002-03-08
影响因子：
20.1
通讯作者：
Ping, P
中科院分区：
文献类型：
--
作者：
Baines, CP;Zhang, J;Ping, P
虽然已知蛋白激酶C (PKC) E和丝裂原活化蛋白激酶（MAPKs）的激活在心脏保护的表现中起着至关重要的作用。PKCepsilon信号模块在初始心肌和受保护心肌中的空间组织尚不清楚。有证据表明线粒体是心脏保护信号的关键介质。我们假设PKCepsilon和MAPKs相互作用，并在心脏保护过程中在线粒体中形成功能性信号模块。免疫印迹和免疫荧光染色均显示PKCepsilon， ERKs。JNKs和p38 MAPK与心脏线粒体共定位。此外，PKCepsilon的转基因激活大大增加了线粒体PKCepsilon的表达和活性，这与PKCepsilon与ERKs的线粒体相互作用增加有关。JNKs和p38通过共免疫沉淀测定。这些复杂的结构似乎与PKCepsilon活性无关，因为在表达失活PKCepsilon的小鼠中也观察到这种相互作用。然而，尽管活性PKCepsilon和非活性PKCepsilon都与所有三种mapk结合，但仅在表达活性PKCepsilon的小鼠中观察到线粒体ERKs磷酸化增加，而在表达非活性PKCepsilon的小鼠中没有观察到。对线粒体PKCepsilon-ERK信号模块的潜在下游靶点的检测显示，线粒体中促凋亡蛋白Bad的磷酸化水平升高。总之，这些数据表明PKCepsilon与ERKs形成亚细胞靶向信号模块，导致线粒体ERKs的激活。此外，线粒体PKCepsilon-ERK模块的形成似乎在pkcepsilon介导的心脏保护中发挥作用，部分原因是Bad的磷酸化和失活。
dAlthough activation of protein kinase C (PKC) E and mitogen-activated protein kinases (MAPKs) are known to play crucial roles in the manifestation of cardioprotection. the spatial organization of PKCepsilon signaling modules in naive and protected myocardium remains unknown. Based on evidence that mitochondria a-re key mediators of the cardioprotective signal. we hypothesized that PKCepsilon and MAPKs interact, and that they form functional signaling modules in mitochondria during cardioprotection. Both immunoblotting and immunofluorescent staining demonstrated that PKCepsilon, ERKs. JNKs, and p38 MAPK co-localized with cardiac mitochondria. Moreover, transgenic activation of PKCepsilon greatly increased mitochondrial PKCepsilon expression and activity, which was concomitant with increased mitochondrial interaction of PKCepsilon with ERKs. JNKs, and p38 as determined by co-immunoprecipitation. These complex formations appeared to be independent of PKCepsilon activity, as the interactions were also observed in mice expressing inactive PKCepsilon. However, although both active and inactive PKCepsilon bound to all three MAPKs, increased phosphorylation of mitochondrial ERKs was only observed in mice expressing active PKCepsilon but not in mice expressing inactive PKCepsilon. Examination of potential downstream targets of mitochondrial PKCepsilon-ERK signaling modules revealed that phosphorylation of the pro-apoptotic protein Bad was elevated in mitochondria. Together, these data show that PKCepsilon forms subcellular-targeted signaling modules with ERKs, leading to the activation of mitochondrial ERKs. Furthermore, formation of mitochondrial PKCepsilon-ERK modules appears to play a role in PKCepsilon-mediated cardioprotection, in part by the phosphorylation and inactivation of Bad.