Cleavage of SPACA1 regulates assembly of sperm?egg membrane fusion machinery in mature spermatozoa†
Cleavage of SPACA1 regulates assembly of sperm?egg membrane fusion machinery in mature spermatozoa†
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SPACA1 的裂解调节成熟精子中精卵膜融合机制的组装†
DOI：
10.1093/biolre/ioz223
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发表时间：
2019
影响因子：
3.6
通讯作者：
Toshimori Kiyotaka
中科院分区：
文献类型：
--
作者：
Yamatoya Kenji;Kousaka Marika;Ito Chizuru;Nakata Kazuya;Hatano Masahiko;Araki Yoshihiko;Toshimori Kiyotaka
顶体反应是生理受精过程中必不可少的多步骤反应。在顶体反应过程中，配子融合相关因子IZUMO 1从顶体前部易位到赤道段，组装配子融合机器。顶体反应过程中的形态学变化已经得到了很好的研究，但对生理配子膜融合所必需的顶体重组的分子机制知之甚少。为了阐明IZUMO 1易位的分子机制，必须阐明该过程中顶体反应的步骤。在这项研究中，我们建立了一种方法来检测顶体反应的早期步骤，并通过使用两个表位定义的抗体，抗IZUMO 1和抗SPACA 1，受精抑制抗体细分为7个群体的过程。我们发现，部分SPACA 1的C-末端在顶体周围的空间被切割，并已开始消失时，前顶体的囊泡发生。顶体囊泡化和磷酸化前的顶体腔的IZUMO 1表位外化的IZUMO 1发生在易位到赤道段。IZUMO 1绕过了SPACA 1C末端仍然位于的赤道段区域。因此，我们提出了一个IZUMO 1易位模型和SPACA 1的参与。
The acrosome reaction is a multi-step event essential for physiological fertilization. During the acrosome reaction, gamete fusion-related factor IZUMO1 translocates from the anterior acrosome to the equatorial segment and assembles the gamete fusion machinery. The morphological changes in the acrosome reaction process have been well studied, but little is known about the molecular mechanisms of acrosome reorganization essential for physiological gamete membrane fusion. To elucidate the molecular mechanisms of IZUMO1 translocation, the steps of the acrosome reaction during that process must be clarified. In this study, we established a method to detect the early steps of the acrosome reaction and subdivided the process into seven populations through the use of two epitope-defined antibodies, anti-IZUMO1 and anti-SPACA1, a fertilization-inhibiting antibody. We found that part of the SPACA1 C-terminus in the periacrosomal space was cleaved and had begun to disappear when the vesiculation of the anterior acrosome occurred. The IZUMO1 epitope externalized from the acrosomal lumen before acrosomal vesiculation and phosphorylation of IZUMO1 occurred during the translocation to the equatorial segment. IZUMO1 circumvented the area of the equatorial segment where the SPACA1C-terminus was still localized. We therefore propose an IZUMO1 translocation model and involvement of SPACA1.