Phosphatases control PKA-dependent functional microdomains at the outer mitochondrial membrane.
Phosphatases control PKA-dependent functional microdomains at the outer mitochondrial membrane.
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DOI：
10.1073/pnas.1806318115
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发表时间：
2018-07-10
影响因子：
11.1
通讯作者：
Lefkimmiatis K
中科院分区：
文献类型：
--
作者：
Burdyga A;Surdo NC;Monterisi S;Di Benedetto G;Grisan F;Penna E;Pellegrini L;Zaccolo M;Bortolozzi M;Swietach P;Pozzan T;Lefkimmiatis K
空间上不同的PKA靶点的选择性磷酸化是cAMP级联多效性的关键。该途径的这种特性目前归因于磷酸二酯酶或腺苷酸环化酶产生亚细胞位点（微域）的能力，其中cAMP的浓度与周围区域的浓度不同。磷酸酶在这一过程中的作用尚未得到证实。本研究表明，尽管局部cAMP水平没有差异，但磷酸酶对存在于线粒体外膜的PKA靶点的有限通路会产生不同的PKA磷酸化蛋白微域。这些结果描述了一种能够产生功能性cAMP/ pka依赖微域的替代机制，并可以推断为其他激酶依赖事件的区隔化。支持cAMP和PKA信号异质性的证据正在迅速积累，这在很大程度上归因于腺苷酸环化酶、磷酸二酯酶和a激酶锚定蛋白在不同细胞亚室中的定位或活性。然而，很少有人注意到这样一种可能性，即尽管cAMP水平均匀，但cAMP/PKA信号的主要异质性可能是由该级联的最终终止子（即磷酸酶）的空间分布产生的。利用基于fret的传感器监测原代大鼠心肌细胞细胞质和线粒体外膜（OMM）中cAMP和pka依赖性磷酸化，我们发现这两个区室中cAMP的增加引起OMM中更高水平的pka依赖性磷酸化。这种差异在cAMP水平和OMM定位探针和内源性OMM蛋白的小幅生理增加中最为明显。我们证明，这种差异取决于两个区室中PKA靶点磷酸酶依赖性去磷酸化速率的差异。此外，我们发现可溶性磷酸酶的活性减弱了pka驱动的cAMP反应元件结合蛋白的激活，同时增强了pka依赖的线粒体伸长。我们得出结论，磷酸酶可以雕刻功能不同的cAMP/PKA结构域，即使在没有梯度或微结构域的情况下。我们提出了一个模型来解释这些意想不到的结果，其中pka依赖性磷酸化的程度由磷酸酶的亚细胞分布和膜结合和可溶性磷酸化底物对细胞质酶的不同可及性决定。
The selective phosphorylation of spatially distinct PKA targets is key for the pleiotropy of the cAMP cascade. This characteristic of the pathway is currently attributed to the ability of phosphodiesterases or adenylate cyclases to create subcellular sites (microdomains) where the concentration of cAMP is distinct from that of the surrounding areas. The role of phosphatases in this process has not been tested. Here we show that limited access of phosphatases to the PKA targets present at the outer mitochondrial membrane generates distinct microdomains of PKA phosphorylated proteins despite there being no differences in the local cAMP levels. These results describe an alternative mechanism capable of generating functional cAMP/PKA-dependent microdomains and may be extrapolated to the compartmentalization of other kinase-dependent events. Evidence supporting the heterogeneity in cAMP and PKA signaling is rapidly accumulating and has been largely attributed to the localization or activity of adenylate cyclases, phosphodiesterases, and A-kinase–anchoring proteins in different cellular subcompartments. However, little attention has been paid to the possibility that, despite homogeneous cAMP levels, a major heterogeneity in cAMP/PKA signaling could be generated by the spatial distribution of the final terminators of this cascade, i.e., the phosphatases. Using FRET-based sensors to monitor cAMP and PKA-dependent phosphorylation in the cytosol and outer mitochondrial membrane (OMM) of primary rat cardiomyocytes, we demonstrate that comparable cAMP increases in these two compartments evoke higher levels of PKA-dependent phosphorylation in the OMM. This difference is most evident for small, physiological increases of cAMP levels and with both OMM-located probes and endogenous OMM proteins. We demonstrate that this disparity depends on differences in the rates of phosphatase-dependent dephosphorylation of PKA targets in the two compartments. Furthermore, we show that the activity of soluble phosphatases attenuates PKA-driven activation of the cAMP response element-binding protein while concurrently enhancing PKA-dependent mitochondrial elongation. We conclude that phosphatases can sculpt functionally distinct cAMP/PKA domains even in the absence of gradients or microdomains of this messenger. We present a model that accounts for these unexpected results in which the degree of PKA-dependent phosphorylation is dictated by both the subcellular distribution of the phosphatases and the different accessibility of membrane-bound and soluble phosphorylated substrates to the cytosolic enzymes.
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影响因子：
3.7
作者：
Klarenbeek J;Goedhart J;van Batenburg A;Groenewald D;Jalink K
通讯作者：
Jalink K
DOI：
10.1038/nrm3072
发表时间：
2011-03
期刊：
Nature reviews. Molecular cell biology
影响因子：
--
作者：
通讯作者：
--
影响因子：
29
作者：
Di Benedetto, Giulietta;Scalzotto, Elisa;Pozzan, Tullio
通讯作者：
Pozzan, Tullio
影响因子：
16
作者：
Heinrich, R;Neel, BG;Rapoport, TA
通讯作者：
Rapoport, TA
影响因子：
--
作者：
Depry, Charlene;Allen, Michael D.;Zhang, Jin
通讯作者：
Zhang, Jin