DIRECT IDENTIFICATION OF PROHORMONE CONVERSION SITE IN INSULIN-SECRETING CELLS
DIRECT IDENTIFICATION OF PROHORMONE CONVERSION SITE IN INSULIN-SECRETING CELLS
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DOI：
10.1016/0092-8674(85)90124-2
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发表时间：
1985-01-01
期刊：
影响因子：
64.5
通讯作者：
PERRELET, A
中科院分区：
文献类型：
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作者：
ORCI, L;RAVAZZOLA, M;PERRELET, A
我们使用免疫细胞化学揭示的胰岛素原特异性单克隆抗体，在人和大鼠胰岛的 B 细胞中定位了胰岛素原。高尔基体堆和网格蛋白包被的分泌颗粒中富含胰岛素原。当蛋白质合成受到抑制时，它会迅速从这些区室中消失。 ATP 储备的耗尽会阻止胰岛素原从高尔基体堆栈移动到分泌颗粒；在这些条件下，预制包衣颗粒中的激素原会转化为胰岛素，而与高尔基复合体结合的激素原则不会。未包衣颗粒在所有孵育方案下均显示出低水平的胰岛素原反应性。这些发现提供了直接证据，表明包被的分泌颗粒是胰岛素原向胰岛素转化的主要（如果不是唯一的）细胞位点。他们还表明，高尔基体堆栈不参与转化，并且池间运输和包衣颗粒形成是迄今为止尚未认识到的转化之前的能量需求步骤。
We have localized proinsulin in B cells of human and rat pancreatic islets, using a proinsulin-specific monoclonal antibody revealed by immunocytochemistry. Proinsulin is abundant in Golgi stacks and clathrin-coated secretory granules. It rapidly disappears from these compartments when protein synthesis is inhibited. Depletion of ATP stores prevents movement of proinsulin from the Golgi stacks to the secretory granules; under these conditions, the prohormone in preformed coated granules is converted to insulin, whereas that bound to the Golgi complex is not. Non-coated granules show a low level of proinsulin reactivity under all incubation protocols. These findings provide direct evidence that coated secretory granules are the major, if not the only, cellular site of proinsulin to insulin conversion. They also suggest that the Golgi stack is not involved in conversion, and that intercisternal transport and coated granule formation are hitherto unrecognized energy-requiring steps that precede conversion.