Departments of Biochemistry and Cell Biology and of Farm Animal Health, Research Program: Biology of Reproductive Cells, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands.
Adv Exp Med Biol. 2011;713:65-80. doi: 10.1007/978-94-007-0763-4_5.
Successful completion of fertilization in mammals requires three different types of membrane fusion events. Firstly, the sperm cell will need to secrete its acrosome contents (acrosome exocytosis; also known as the acrosome reaction); this allows the sperm to penetrate the extracellular matrix of the oocyte (zona pellucida) and to reach the oocyte plasma membrane, the site of fertilization. Next the sperm cell will bind and fuse with the oocyte plasma membrane (also known as the oolemma), which is a different type of fusion in which two different cells fuse together. Finally, the fertilized oocyte needs to prevent polyspermic fertilization, or fertilization by more than one sperm. To this end, the oocyte secretes the contents of cortical granules by exocytotic fusions of these vesicles with the oocyte plasma membrane over the entire oocyte cell surface (also known as the cortical reaction or cortical granule exocytosis). The secreted cortical contents modify the zona pellucida, converting it to a state that is unreceptive to sperm, constituting a block to polyspermy. In addition, there is a block at the level of the oolemma (also known as the membrane block to polyspermy).
哺乳动物受精的成功完成需要三种不同类型的膜融合事件。首先，精子细胞需要分泌其顶体内容物（顶体胞吐作用；也称为顶体反应）；这使得精子能够穿透卵母细胞的细胞外基质（透明带）并到达卵母细胞的质膜，这是受精的部位。接下来，精子细胞将与卵母细胞质膜结合并融合（也称为卵母细胞膜融合），这是一种不同类型的融合，其中两个不同的细胞融合在一起。最后，受精卵需要防止多精受精，即一个卵子被多个精子受精。为此，卵子通过这些小泡与卵母细胞质膜的胞吐融合，将皮质颗粒的内容物分泌到整个卵子细胞表面（也称为皮质反应或皮质颗粒胞吐作用）。分泌的皮质物质改变了透明带的状态，使其对精子不再具有接受性，构成了多精受精的障碍。此外，在卵母细胞膜水平也存在一种障碍（也称为多精受精的膜障碍）。
