Klinovska Karolina, Sebkova Natasa, Dvorakova-Hortova Katerina
BIOCEV Group, Department of Zoology, Charles University in Prague, Vinicna 7, Prague 2 128 44, Czech Republic.
Int J Mol Sci. 2014 Jun 13;15(6):10652-68. doi: 10.3390/ijms150610652.
The mechanism of gamete fusion remains largely unknown on a molecular level despite its indisputable significance. Only a few of the molecules required for membrane interaction are known, among them IZUMO1, which is present on sperm, tetraspanin CD9, which is present on the egg, and the newly found oolema protein named Juno. A concept of a large multiprotein complex on both membranes forming fusion machinery has recently emerged. The Juno and IZUMO1, up to present, is the only known extracellular receptor pair in the process of fertilization, thus, facilitating the essential binding of gametes. However, neither IZUMO1 nor Juno appears to be the fusogenic protein. At the same time, the tetraspanin is expected to play a role in organizing the egg membrane order and to interact laterally with other factors. This review summarizes, to present, the known molecules involved in the process of sperm-egg fusion. The complexity and expected redundancy of the involved factors makes the process an intricate and still poorly understood mechanism, which is difficult to comprehend in its full distinction.
尽管配子融合具有无可争议的重要性，但其在分子水平上的机制仍 largely 未知。目前仅知晓少数几种参与膜相互作用的分子，其中包括精子上存在的 IZUMO1、卵子上存在的四跨膜蛋白 CD9 以及新发现的名为 Juno 的卵膜蛋白。最近出现了一种关于在两个膜上形成融合机制的大型多蛋白复合物的概念。到目前为止，Juno 和 IZUMO1 是受精过程中唯一已知的细胞外受体对，从而促进了配子的关键结合。然而，IZUMO1 和 Juno 似乎都不是融合蛋白。同时，预计四跨膜蛋白在组织卵膜秩序以及与其他因子横向相互作用中发挥作用。本综述总结了目前已知的参与精卵融合过程的分子。所涉及因子的复杂性和预期的冗余性使得该过程成为一个复杂且仍知之甚少的机制，难以全面理解其差异。
