Tooze S A, Huttner W B
European Molecular Biology Laboratory, Heidelberg, Federal Republic of Germany.
Cell. 1990 Mar 9;60(5):837-47. doi: 10.1016/0092-8674(90)90097-x.
To elucidate the mechanism of secretory granule formation, we here identify the first intermediate in this process, the immature secretory granule, in the neuroendocrine cell line PC12 and demonstrate the packaging of a regulated secretory protein, secretogranin II, to immature secretory granules in a cell-free system. The formation of immature secretory granules was as fast (t1/2 approximately 5 min) as that of constitutive secretory vesicles identified by the presence of a rapidly secreted heparan sulfate proteoglycan. Using the cell-free system, the formation of post-Golgi secretory vesicles was found to be dependent upon ATP. Two distinct populations of vesicles were formed: immature secretory granules containing secretogranin II and constitutive secretory vesicles containing the heparan sulfate proteoglycan. These results show that in a cell-free system, a constitutive and a regulated secretory protein are sorted upon exit from the trans-Golgi network.
为阐明分泌颗粒形成的机制，我们在此鉴定了此过程中的首个中间体——未成熟分泌颗粒，该颗粒存在于神经内分泌细胞系PC12中，并在无细胞体系中证实了一种受调控的分泌蛋白——分泌粒蛋白II被包装进未成熟分泌颗粒。未成熟分泌颗粒的形成速度（半衰期约为5分钟）与通过快速分泌的硫酸乙酰肝素蛋白聚糖的存在鉴定出的组成型分泌囊泡的形成速度一样快。利用无细胞体系，发现高尔基体后分泌囊泡的形成依赖于ATP。形成了两种不同类型的囊泡：含有分泌粒蛋白II的未成熟分泌颗粒和含有硫酸乙酰肝素蛋白聚糖的组成型分泌囊泡。这些结果表明，在无细胞体系中，一种组成型分泌蛋白和一种受调控的分泌蛋白在从反式高尔基体网络排出时被分选。
