Targeted Activation of Conventional and Novel Protein Kinases C through Differential Translocation Patterns
Targeted Activation of Conventional and Novel Protein Kinases C through Differential Translocation Patterns
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DOI：
10.1128/mcb.00040-14
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发表时间：
2014-07-01
影响因子：
5.3
通讯作者：
Lipp, Peter
中科院分区：
文献类型：
--
作者：
Hui, Xin;Reither, Gregor;Lipp, Peter
蛋白激酶A（PKA）和蛋白激酶C（PKC）这两个普遍存在的蛋白激酶家族的激活被认为分别独立地与G α（s）和G α（q）的刺激偶联。蛋白激酶C荧光蛋白融合构建体的活细胞共聚焦成像显示，G α（s）和G α（q）的同时激活导致常规PKC α向质膜的差异易位，而新的PKC δ被募集到内质网（ER）的膜。我们证明PKC α易位是由一种新的G α（s）-环AMP-EPAC-RAP-PLC β途径驱动的，导致ER膜上特异性二酰甘油的产生。膜特异性磷酸化传感器显示，定向易位导致磷酸化活性局限于靶膜。PKC δ的特异性刺激引起肌醇-1，4，5-三磷酸受体的磷酸化，并通过笼状肌醇-1，4，5-三磷酸的分级闪光光解揭示了全球Ca 2+信号传导的抑制。我们的数据表明，一种新的信号通路，使差分解码传入的刺激PKC亚型特异性膜靶向，显着提高环AMP信号的多功能性，从而证明了传统上独立处理的PKA和PKC通路之间的可能的互连。因此，我们提供了新的和基本的理解和见解细胞内信号事件。
Activation of the two ubiquitous families of protein kinases, protein kinase A (PKA) and protein kinase C (PKC), is thought to be independently coupled to stimulation of G alpha(s) and G alpha(q), respectively. Live-cell confocal imaging of protein kinase C fluorescent protein fusion constructs revealed that simultaneous activation of G alpha(s) and G alpha(q) resulted in a differential translocation of the conventional PKC alpha to the plasma membrane while the novel PKC delta was recruited to the membrane of the endoplasmic reticulum (ER). We demonstrate that the PKC alpha translocation was driven by a novel G alpha(s)-cyclic AMP-EPAC-RAP-PLC epsilon pathway resulting in specific diacylglycerol production at the membrane of the ER. Membrane-specific phosphorylation sensors revealed that directed translocation resulted in phosphorylation activity confined to the target membrane. Specific stimulation of PKC delta caused phosphorylation of the inositol-1,4,5-trisphosphate receptor and dampening of global Ca2+ signaling revealed by graded flash photolysis of caged inositol-1,4,5-trisphosphate. Our data demonstrate a novel signaling pathway enabling differential decoding of incoming stimuli into PKC isoform-specific membrane targeting, significantly enhancing the versatility of cyclic AMP signaling, thus demonstrating the possible interconnection between the PKA and PKC pathways traditionally treated independently. We thus provide novel and elementary understanding and insights into intracellular signaling events.