Vesicle size determines unitary exocytic properties and their sensitivity to sphingosine
Vesicle size determines unitary exocytic properties and their sensitivity to sphingosine
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DOI：
10.1016/j.mce.2013.06.012
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发表时间：
2013-08-25
影响因子：
4.1
通讯作者：
Zorec, Robert
中科院分区：
文献类型：
--
作者：
Flasker, Ajda;Jorgacevski, Jernej;Zorec, Robert
神经内分泌细胞含有大小不同的囊泡，但囊泡直径的功能意义尚不清楚。我们通过监测膜电容中的离散步骤，研究了催乳素囊泡在催乳素细胞中的单一胞吐事件。在鞘氨醇的存在下，其募集VAMP2用于SNARE复合物的形成，瞬时和完全融合事件的频率增加。直径较大的囊泡进行充分融合，但较小的囊泡仍然陷入短暂的胞吐。通过完全融合胞吐作用释放到细胞外空间的囊泡致密核心的直径大于质膜下剩余的胞内囊泡的直径。用催乳素和VAMP2抗体标记揭示了共定位的催乳素和VAMP2阳性结构的直径之间的相关性。有人建议，鞘氨醇介导的促进调节胞吐不仅涉及到每个囊泡的陷阱复合物的数量，但也取决于囊泡的大小，这可能决定了过渡之间的短暂和完全融合胞吐。(C)2013爱思唯尔爱尔兰有限公司版权所有。
Neuroendocrine cells contain small and large vesicles, but the functional significance of vesicle diameter is unclear. We studied unitary exocytic events of prolactin-containing vesicles in lactotrophs by monitoring discrete steps in membrane capacitance. In the presence of sphingosine, which recruits VAMP2 for SNARE complex formation, the frequency of transient and full fusion events increased. Vesicles with larger diameters proceeded to full fusion, but smaller vesicles remained entrapped in transient exocytosis. The diameter of vesicle dense cores released by full fusion exocytosis into the extracellular space was larger than the diameter of the remaining intracellular vesicles beneath the plasma membrane. Labeling with prolactin- and VAMP2-antibodies revealed a correlation between the diameters of colocalized prolactin- and VAMP2-positive structures. It is proposed that sphingosine-mediated facilitation of regulated exocytosis is not only related to the number of SNARE complexes per vesicle but also depends on the vesicle size, which may determine the transition between transient and full fusion exocytosis. (C) 2013 Elsevier Ireland Ltd. All rights reserved.