Role of zonadhesin during sperm–egg interaction: a species-specific acrosomal molecule with multiple functions

Abstract

Sperm-zona adhesion is an essential event in mammalian fertilization, failure of which causes sterility. However, the molecular mechanisms involved in this process are still poorly understood. It has been suggested by few laboratories studying gamete interaction that acrosomal molecules are implicated in sperm -zona pellucida adhesion prior to the acrosome reaction (AR). Zonadhesin, a spermspecific protein located in the acrosome is critically involved in zona binding. Here we describe the cellular and molecular interaction of zonadhesin during fertilization and also discuss its role in species-specific gamete interaction-an intriguing question in biology. We propose a model in which sperm could transiently expose acrosomal molecules that adhere to the zona independently of the AR in a 'kiss and run' mechanism. This could be a valuable framework for further investigations and a detailed understanding of the molecular events during gamete adhesion is likely to provide new approaches for the design of more effective male contraceptives and better diagnostic methods for sperm dysfunction.

Green spermatozoa illuminate a 30-year-old model: sperm–egg adhesion involves intra-acrosomal proteins

“…However, the molecular mechanism of zonadhesin exposure during capacitation is not yet fully understood. 9 In summary, research on gamete interaction and AR is entering a fascinating new era. The study performed by Jin et al 1 and supported by other 7 represents a major advance in sperm physiology.…”

Sperm function tests in clinical practice

“…Tardif et al [34] proposed a model in which sperm could be transiently exposed to acrosomal molecules that adhere to the zona independent from the AR in a 'kiss and run' mechanism. They concluded that this could be important for further investigations and a detailed understanding of the molecular events during sperm-ovum binding is likely to provide new approaches for the design of more effective male contraceptives and better diagnostic methods for sperm dysfunction.…”

“…They concluded that this could be important for further investigations and a detailed understanding of the molecular events during sperm-ovum binding is likely to provide new approaches for the design of more effective male contraceptives and better diagnostic methods for sperm dysfunction. [34] Acrosome reaction Sperm binding to the ZP triggers the hydrolyzing enzymes known as AR (Figure 4) and only acrosome-reacted spermatozoa can penetrate ZP, bind the oocyte membrane and fuse with oocyte. [35] The release of lytic enzymes and the presence of membrane receptors are required for the acrosome reaction, resulting in penetration of sperm through ZP and integration with the oolema.…”

Immunologically Mediated Male and Female Reproductive Failure

“…They propose a "selective" antigen sequestration model. Nonsequestered antigens, such as testis-specific lactate dehydrogenase (Marsh et al, 1981), are protected by systemic tolerance, whereas sequestered, immunogenic antigens such as zonadhesion (Wheeler et al, 2011;Tardif and Cormier, 2011) are the major promoters of sperm autoimmunity and would dominate in a postvasectomy immune response (Table 1).…”