Biotechnology of Animal and Human Reproduction (TechnoSperm), Institute of Food and Agricultural Technology, University of Girona, ES-17003 Girona, Spain.
Unit of Cell Biology, Department of Biology, Faculty of Sciences, University of Girona, ES-17003 Girona, Spain.
Int J Mol Sci. 2022 Jun 6;23(11):6333. doi: 10.3390/ijms23116333.
Alkalinization of sperm cytosol is essential for plasma membrane hyperpolarization, hyperactivation of motility, and acrosomal exocytosis during sperm capacitation in mammals. The plasma membrane of sperm cells contains different ion channels implicated in the increase of internal pH (pH) by favoring either bicarbonate entrance or proton efflux. Bicarbonate transporters belong to the solute carrier families 4 (SLC4) and 26 (SLC26) and are currently grouped into Na/HCO transporters and Cl/HCO exchangers. Na/HCO transporters are reported to be essential for the initial and fast entrance of HCO that triggers sperm capacitation, whereas Cl/HCO exchangers are responsible for the sustained HCO entrance which orchestrates the sequence of changes associated with sperm capacitation. Proton efflux is required for the fast alkalinization of capacitated sperm cells and the activation of pH-dependent proteins; according to the species, this transport can be mediated by Na/H exchangers (NHE) belonging to the SLC9 family and/or voltage-gated proton channels (HVCN1). Herein, we discuss the involvement of each of these channels in sperm capacitation and the acrosome reaction.
在哺乳动物精子获能过程中，精子胞质的碱化对于质膜超极化、运动的超活化和顶体反应至关重要。精子细胞的质膜含有不同的离子通道，这些通道参与内部 pH 值（pH）的增加，有利于碳酸氢根进入或质子外流。碳酸氢盐转运蛋白属于溶质载体家族 4（SLC4）和 26（SLC26），目前分为 Na/HCO 转运体和 Cl/HCO 交换体。据报道，Na/HCO 转运体对于触发精子获能的 HCO 的初始和快速进入是必不可少的，而 Cl/HCO 交换体则负责持续的 HCO 进入，协调与精子获能相关的一系列变化。质子外流对于获能精子的快速碱化和 pH 依赖性蛋白的激活是必需的；根据物种的不同，这种运输可以由 SLC9 家族的 Na/H 交换体（NHE）和/或电压门控质子通道（HVCN1）介导。本文讨论了这些通道中的每一个在精子获能和顶体反应中的作用。
