T-type (CaV3) channels have been implicated in sperm physiology.
Progesterone-evoked Ca2+ influx via CatSper has been implicated in sperm chemotaxis, hyperactivation, and acrosomal exocytosis (Blackmore et al., 1990; Publicover et al., 2007; Publicover et al., 2008).
The ADAM B sub-group also reveals a tetrapod-specific expansion of five genes (ADAM2, 3, 5, 18 and 32) that play roles in fertility; ADAM2 and 3 are involved in mammalian fertilization [ 45], ADAM5 is expressed in mouse testis [ 46], and ADAM32 has been implicated in sperm-egg fusion [ 47].
It is present in sperm flagella and plays an important role in flagella formation during spermiogenesis as well as being implicated in sperm motility.
Many environmental, physiological and genetic factors have been implicated in defective sperm function, the most common cause of infertility.
Fertilin, the first ADAM described, has been implicated in integrin-mediated sperm-egg binding [ 57].
Furthermore, absent/reduced levels of PLCζ in sperm have been implicated in forms of male infertility where such sperm is repeatedly unable to activate oocytes [ 86, 107, 133].
Mammalian sAC has been implicated in processes such as sperm activation, glucose metabolism, and prostate and skin cancer, making it a potential therapeutic target, and first sAC-specific inhibitors have been developed.
Given that the length of female reproductive tract has been implicated in male fertilization success and sperm competition [e.g.], [25], [36, 37], this proposed Wolbachia-induced modification has the potential to influence the dynamics of fertilization success and even male-female coevolution.
For instance, a study at the University of Birmingham in the UK has uncovered that "prior to fertilization, a cloud of cumulus cells surrounding the egg releases progesterone, the female sex hormone, triggering a calcium influx into the sperm... Progesterone has also been implicated in providing a chemical gradient by which sperm can navigate toward the egg".
Both ACE2 and ZPBP2 have been implicated in the initial binding of the sperm acrosome to ZP [35], [36].
