Dpto. Fisiología Médica y Biofísica, Facultad de Medicina, Universidad de Sevilla, Spain.
Unidad de Farmacología, Facultad de Medicina, Universidad de La Laguna, Spain.
FEBS Lett. 2018 Nov;592(21):3532-3541. doi: 10.1002/1873-3468.13234. Epub 2018 Oct 1.
Membrane fusion and fission are fundamental processes in living organisms. Membrane fusion occurs through the formation of a fusion pore, which is the structure that connects two lipid membranes during their fusion. Fusion pores can form spontaneously, but cells endow themselves with a set of proteins that make the process of fusion faster and regulatable. The fusion pore starts with a narrow diameter and dilates relatively slowly; it may fluctuate in size or can even close completely, producing a transient vesicle fusion (kiss-and-run), or can finally expand abruptly to release all vesicle contents. A set of proteins control the formation, dilation, and eventual closure of the fusion pore and, therefore, the velocity at which the contents of secretory vesicles are released to the extracellular medium. Thus, the regulation of fusion pore expansion or closure is key to regulate the release of neurotransmitters and hormones. Here, we review the phases of the fusion pore and discuss the implications in the modes of exocytosis.
膜融合和裂变是生物体内的基本过程。膜融合通过融合孔的形成来实现，融合孔是连接两个脂质膜在融合过程中的结构。融合孔可以自发形成，但细胞赋予自身一套蛋白质，使融合过程更快且可调节。融合孔开始时直径较窄，相对缓慢地扩张；它可能会波动或甚至完全关闭，产生短暂的囊泡融合（亲吻-跑），或者最终突然扩张以释放所有囊泡内容物。一组蛋白质控制融合孔的形成、扩张和最终关闭，因此，控制着分泌囊泡内容物释放到细胞外介质的速度。因此，融合孔扩张或关闭的调节是调节神经递质和激素释放的关键。在这里，我们回顾融合孔的阶段，并讨论其在胞吐作用模式中的意义。
