Sequential-replenishment mechanism of exocytosis in pancreatic acini
Sequential-replenishment mechanism of exocytosis in pancreatic acini
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DOI：
10.1038/35060042
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发表时间：
2001-03-01
影响因子：
21.3
通讯作者：
Kasai, H
中科院分区：
文献类型：
--
作者：
Nemoto, T;Kimura, R;Kasai, H
在这里，我们报告了酶原颗粒的胞吐作用，正如在完整的胰腺腺泡中通过多光子激发成像所检查的那样，胆囊收缩素诱导Ca 2+振荡，当细胞质Ca 2+浓度超过1 μ M时，触发胞吐作用。与质膜融合的酶原颗粒保持其Ω形轮廓平均220秒，并用作位于细胞深层内的颗粒顺序融合的靶.这种继发性胞吐作用与原发性胞吐作用一样迅速发生，并解释了大多数胞吐事件。颗粒-颗粒融合似乎不先于初级胞吐，表明次级融合事件可能需要质膜因子。这种胞吐的顺序补充机制允许细胞利用大量的融合就绪颗粒供应，而不需要将它们运输到质膜。
Here we report exocytosis of zymogen granules, as examined by multiphoton excitation imaging in intact pancreatic acini, Cholecystokinin induces Ca2+ oscillations that trigger exocytosis when the cytosolic Ca2+ concentration exceeds 1 muM. Zymogen granules fused with the plasma membrane maintain their Omega -shaped profile for an average of 220 s and serve as targets for sequential fusion of granules that are located within deeper layers of the cell. This secondary exocytosis occurrs as rapidly as the primary exocytosis and accounts for most exocytotic events. Granule-granule fusion does not seem to precede primary exocytosis, indicating that secondary fusion events may require a plasma-membrane factor, This sequential-replenishment mechanism of exocytosis allows the cell to take advantage of a large supply of fusion-ready granules without needing to transport them to the plasma membrane.