Calcium-regulated exocytosis is required for cell membrane resealing.
Calcium-regulated exocytosis is required for cell membrane resealing.
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DOI：
10.1083/jcb.131.6.1747
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发表时间：
1995-12
期刊：
影响因子：
--
通讯作者：
Steinhardt RA
中科院分区：
文献类型：
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作者：
Bi GQ;Alderton JM;Steinhardt RA
利用共聚焦显微镜，我们观察了海胆卵和胚胎在膜重封过程中的胞外分泌。在激光束损伤后，卵子和胚胎都表现出局部Ca（2+）调节的胞吐快速爆发。胞吐率与成功重封有定量关系。在胚胎中，激活的表面在融合前必须先与囊泡对接，细胞外分泌和膜重封被选择性切割SNARE复合体蛋白、synaptobrevin、SNAP-25和syntaxin的神经毒素所抑制。在卵子中，其皮质囊泡已经对接，外用水苏糖可以可逆地解除囊泡对接。如果皮质小泡被断开，胞吐和质膜再密封都被完全抑制。当皮质囊泡暂时断开时，暴露于破伤风毒素和C1型肉毒杆菌神经毒素使它们不再有能力重新闭合，尽管A型肉毒杆菌神经毒素仍然无效。皮质囊泡在破伤风毒素的存在下暂时断开，随后融合能力不足，尽管在很大程度上，当水苏糖被稀释时，它们保留了重新连接的能力。我们得出结论，胞外作用需要增加细胞膜，并且snare样复合体在囊泡对接和融合中起着不同的作用，以修复被破坏的质膜。
Using confocal microscopy, we visualized exocytosis during membrane resealing in sea urchin eggs and embryos. Upon wounding by a laser beam, both eggs and embryos showed a rapid burst of localized Ca(2+)- regulated exocytosis. The rate of exocytosis was correlated quantitatively with successfully resealing. In embryos, whose activated surfaces must first dock vesicles before fusion, exocytosis and membrane resealing were inhibited by neurotoxins that selectively cleave the SNARE complex proteins, synaptobrevin, SNAP-25, and syntaxin. In eggs, whose cortical vesicles are already docked, vesicles could be reversibly undocked with externally applied stachyose. If cortical vesicles were undocked both exocytosis and plasma membrane resealing were completely inhibited. When cortical vesicles were transiently undocked, exposure to tetanus toxin and botulinum neurotoxin type C1 rendered them no longer competent for resealing, although botulinum neurotoxin type A was still ineffective. Cortical vesicles transiently undocked in the presence of tetanus toxin were subsequently fusion incompetent although to a large extent they retained their ability to redock when stachyose was diluted. We conclude that addition of internal membranes by exocytosis is required and that a SNARE-like complex plays differential roles in vesicle docking and fusion for the repair of disrupted plasma membrane.