Reproductive Science Group, School of Environmental and Life Sciences, Discipline of Biological Sciences, University of Newcastle, Callaghan, New South Wales 2308, Australia.
J Biol Chem. 2011 Oct 21;286(42):36875-87. doi: 10.1074/jbc.M110.188888. Epub 2011 Aug 31.
Sperm-oocyte interactions are among the most remarkable processes in cell biology. These cellular recognition events are initiated by an exquisitely specific adhesion of free-swimming spermatozoa to the zona pellucida, an acellular matrix that surrounds the ovulated oocyte. Decades of research focusing on this interaction have led to the establishment of a widely held paradigm that the zona pellucida receptor is a single molecular entity that is constitutively expressed on the sperm cell surface. In contrast, we have employed the techniques of blue native-polyacrylamide gel electrophoresis, far Western blotting, and proximity ligation to secure the first direct evidence in support of a novel hypothesis that zona binding is mediated by multimeric sperm receptor complex(es). Furthermore, we show that one such multimeric association, comprising the chaperonin-containing TCP1 complex (CCT/TRiC) and a zona-binding protein, zona pellucida-binding protein 2, is present on the surface of capacitated spermatozoa and could account for the zona binding activity of these cells. Collectively, these data provide an important biochemical insight into the molecular basis of sperm-zona pellucida interaction and a plausible explanation for how spermatozoa gain their ability to fertilize.
精卵相互作用是细胞生物学中最显著的过程之一。这些细胞识别事件是由自由游动的精子对透明带的高度特异性附着引发的，透明带是围绕排卵卵母细胞的无细胞基质。几十年来，专注于这一相互作用的研究导致了一个广泛持有的范式的建立，即透明带受体是一个在精子细胞表面持续表达的单一分子实体。相比之下，我们采用了蓝色 native-聚丙烯酰胺凝胶电泳、远 Western 印迹和邻近连接技术，首次提供了直接证据支持一个新的假设，即透明带结合是由多聚体精子受体复合物介导的。此外，我们表明，这样的多聚体缔合之一，由含 chaperonin 的 TCP1 复合物 (CCT/TRiC) 和透明带结合蛋白 2 组成，存在于获能精子的表面上，并可以解释这些细胞的透明带结合活性。总的来说，这些数据为精子-透明带相互作用的分子基础提供了重要的生化见解，并为精子如何获得受精能力提供了合理的解释。
