The Golgi apparatus regulates cGMP-dependent protein kinase I compartmentation and proteolysis.
The Golgi apparatus regulates cGMP-dependent protein kinase I compartmentation and proteolysis.
复制标题
DOI：
10.1152/ajpcell.00199.2014
复制
发表时间：
2015-06
期刊：
影响因子：
--
通讯作者：
S. Kato;Jingsi Chen;Katherine H Cornog;Huili Zhang;Jesse D. Roberts
中科院分区：
文献类型：
--
作者：
S. Kato;Jingsi Chen;Katherine H Cornog;Huili Zhang;Jesse D. Roberts
cGMP依赖性蛋白激酶I（PKGI）是cGMP信号的重要效应子，调节血管平滑肌细胞（SMC）的表型和增殖。PKGI已经在细胞的核周区域中被检测到，并且最近的数据表明，通常驻留在高尔基体（GA）中的前蛋白转化酶（PC）可以刺激PKGI蛋白水解并产生定位于细胞核并调节基因表达的激酶片段。然而，内膜系统在PKGI区室化和加工中的作用尚不清楚。在这里，我们表明，PKGI共定位与内质网（ER），ER-高尔基中间室，GA池，和trans-Golgi网络蛋白在肺动脉SMC和细胞系。此外，PKGI与弗林蛋白酶定位，弗林蛋白酶是一种已知切割PKGI的跨高尔基体网络驻留PC。ER蛋白转运影响PKGI定位，因为组成性失活的Sar 1转基因的过表达导致PKGI滞留在ER中。此外，PKGI似乎存在于GA内，因为PKGI免疫反应性被确定为对活细胞中的胞质蛋白酶K处理具有抗性。GA似乎在PKGI蛋白水解中起作用，因为1，4，5-三磷酸肌醇受体相关cGMP激酶底物的过表达不仅将异源PKGI-β束缚于ER并减少其在GA的定位，而且还减少PKGI蛋白水解和核转位。此外，观察到用莫能菌素抑制GA内蛋白转运降低PKGI切割。这些研究详细说明了内膜系统在调节PKGI区室化和蛋白水解中的作用。此外，他们支持的机制调节PKGI依赖性核cGMP信号在肺血管高尔基体功能障碍的调查。
cGMP-dependent protein kinase I (PKGI) is an important effector of cGMP signaling that regulates vascular smooth muscle cell (SMC) phenotype and proliferation. PKGI has been detected in the perinuclear region of cells, and recent data indicate that proprotein convertases (PCs) typically resident in the Golgi apparatus (GA) can stimulate PKGI proteolysis and generate a kinase fragment that localizes to the nucleus and regulates gene expression. However, the role of the endomembrane system in PKGI compartmentation and processing is unknown. Here, we demonstrate that PKGI colocalizes with endoplasmic reticulum (ER), ER-Golgi intermediate compartment, GA cisterna, and trans-Golgi network proteins in pulmonary artery SMC and cell lines. Moreover, PKGI localizes with furin, a trans-Golgi network-resident PC known to cleave PKGI. ER protein transport influences PKGI localization because overexpression of a constitutively inactive Sar1 transgene caused PKGI retention in the ER. Additionally, PKGI appears to reside within the GA because PKGI immunoreactivity was determined to be resistant to cytosolic proteinase K treatment in live cells. The GA appears to play a role in PKGI proteolysis because overexpression of inositol 1,4,5-trisphosphate receptor-associated cGMP kinase substrate, not only tethered heterologous PKGI-β to the ER and decreased its localization to the GA, but also diminished PKGI proteolysis and nuclear translocation. Also, inhibiting intra-GA protein transport with monensin was observed to decrease PKGI cleavage. These studies detail a role for the endomembrane system in regulating PKGI compartmentation and proteolysis. Moreover, they support the investigation of mechanisms regulating PKGI-dependent nuclear cGMP signaling in the pulmonary vasculature with Golgi dysfunction.