COMPOUND VERSUS MULTIGRANULAR EXOCYTOSIS IN PERITONEAL MAST-CELLS
COMPOUND VERSUS MULTIGRANULAR EXOCYTOSIS IN PERITONEAL MAST-CELLS
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DOI：
10.1085/jgp.95.3.397
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发表时间：
1990-03-01
影响因子：
3.8
通讯作者：
FERNANDEZ, JM
中科院分区：
文献类型：
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作者：
DETOLEDO, GA;FERNANDEZ, JM
我们已经使用了全细胞膜片吸管技术来测量的步骤增加细胞膜电容（相当于膜面积）所造成的分泌颗粒在脱粒小鼠肥大细胞的融合。我们已经观察到，高达30%的总膜扩张所造成的脱粒结果从大融合事件，不能解释的单个分泌颗粒的融合。这些大事件主要在脱粒的初始阶段观察到。我们已经开发了一个简单的数学模型的肥大细胞，以测试这些大的事件是否是由刺激诱导的，颗粒到颗粒的融合，发生在他们的胞吐（多颗粒胞吐）。我们的研究结果表明，大的融合事件是由胞吐的颗粒聚集体，存在于刺激之前，并位于细胞的周边。我们提出了一种新的机制，颗粒聚集体可以形成在细胞的外围。这种机制依赖于瞬时融合的颗粒（“闪烁”）以顺序方式与更多位于内部的颗粒融合的能力。这种模式可能会导致形成较大的周边颗粒，稍后可以与膜融合。外周颗粒聚集体的形成可能增强随后的分泌反应。
We have used the whole-cell patch-pipette technique to measure the step increases in the cell membrane capacitance (equivalent to the membrane area) caused by the fusion of secretory granules in degranulating murine mast cells. We have observed that up to 30% of the total membrane expansion caused by degranulation results from large fusion events that cannot be explained by the fusion of single secretory granules. These large events are observed mainly in the initial phase of a degranulation. We have developed a simple mathematical model for a mast cell to test whether these large events are caused by a stimulus-induced, granule-to-granule fusion that occurs before their exocytosis (multigranular exocytosis). Our results suggest that the large fusion events are caused by the exocytosis of granule aggregates that existed before stimulation and that are located at the cell's periphery. We propose a novel mechanism by which granule aggregates can be formed at the periphery of the cell. This mechanism relies on the ability of a transiently fused granule ("flicker") to fuse with more internally located granules in a sequential manner. This pattern may result in the formation of larger peripheral granules that later on can fuse with the membrane. The formation of peripheral granule aggregates may potentiate a subsequent secretory response.