Golgi structural stability and biogenesis depend on associated PKA activity
Golgi structural stability and biogenesis depend on associated PKA activity
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DOI：
10.1242/jcs.03146
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发表时间：
2006-09-15
影响因子：
4
通讯作者：
Velasco, Angel
中科院分区：
文献类型：
--
作者：
Bejarano, Eloy;Cabrera, Margarita;Velasco, Angel
哺乳动物高尔基复合体由横向连接成连续核周带状结构的成堆的池组成。蛋白激酶 A 在间期期间与高尔基复合体稳定相关。为了分析其在高尔基体结构维持中的作用，使用小干扰 RNA 去除了细胞中的蛋白激酶 A 调节亚基。在这些条件下，催化亚基重新分布到细胞质中，整个高尔基复合体被分解成多个近核片段。在药理学抑制或完整全酶重新分布到细胞质中后，发生了类似的效果。高尔基体片段保持其极化和顺行蛋白质运输的能力。通过电子显微镜，它们被鉴定为由同心排列的水池组成的螺纹状结构。为了测试蛋白激酶 A 在高尔基体生物发生中的可能作用，我们分析了它在高尔基体从内质网重新组装过程中的参与情况。在用蛋白激酶 A 抑制剂孵育的细胞中，高尔基体重建在重新组装过程的后期被阻止。这与重组过程中酶从细胞质招募到新兴高尔基体膜的阶段一致。我们得出的结论是，蛋白激酶 A 活性在从分离的膜堆叠组装和维持连续高尔基带的过程中发挥着相关作用。
The mammalian Golgi complex consists of stacks of cisternae linked laterally into a continuous perinuclear ribbon structure. Protein kinase A is stably associated with the Golgi complex during interphase. To analyze its role in Golgi structural maintenance cells were depleted of protein kinase A regulatory subunits using small interfering RNAs. Under these conditions, the catalytic subunits redistributed to the cytosol and the entire Golgi complex underwent disassembly into multiple juxtanuclear fragments. A similar effect took place following pharmacological inhibition or redistribution of the complete holoenzyme to the cytosol. Golgi fragments maintained their polarization and competence for anterograde protein trafficking. By electron microscopy, they were identified as whorl-like structures composed of concentrically arrayed cisternae. To test a possible role of protein kinase A in Golgi biogenesis we analyzed its involvement during Golgi reassembly from the endoplasmic reticulum. In cells incubated with protein kinase A inhibitors, Golgi reconstruction was arrested at a late step of the reassembly process. This is consistent with the stage of enzyme recruitment from cytosol to emerging Golgi membranes during the reassembly process. We conclude that protein kinase A activity plays a relevant role in the assembly and maintenance of a continuous Golgi ribbon from separated membrane stacks.