disintegrin Disintegrins are a family of small proteins (45–84 amino acids in length) from viper venoms that function as potent inhibitors of both platelet aggregation and integrin-dependent cell adhesion. Operation Disintegrins work by countering the blo ...

and metalloprotease 3, or ADAM3, belongs to a family of peptidase

protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, respo ...

s referred to as ADAMs. Many of these are solely found in spermatogenic cells, specifically in the anterior portion of capacitated spermatozoa heads. This membrane protein is critical for crucial steps in

fertilization Fertilisation or fertilization (see spelling differences), also known as generative fertilisation, syngamy and impregnation, is the fusion of gametes to give rise to a new individual organism or offspring and initiate its development. Proce ...

such as migration of

sperm Sperm is the male reproductive cell, or gamete, in anisogamous forms of sexual reproduction (forms in which there is a larger, female reproductive cell and a smaller, male one). Animals produce motile sperm with a tail known as a flagellum, whi ...

through the

uterus The uterus (from Latin ''uterus'', plural ''uteri'') or womb () is the organ in the reproductive system of most female mammals, including humans that accommodates the embryonic and fetal development of one or more embryos until birth. The uter ...

to the oviduct as well as binding to the zona pellucida. Inactivation of ADAM3 is a cause of male infertility. Numerous studies have detailed that in ADAM3 null mice, the

spermatozoa A spermatozoon (; also spelled spermatozoön; ; ) is a motile sperm cell, or moving form of the haploid cell that is the male gamete. A spermatozoon joins an ovum to form a zygote. (A zygote is a single cell, with a complete set of chromosomes, ...

fail to migrate through the utero-tubal junction. Furthermore, knockout of the closely related ADAM1a gene in mice, an

estrogen Estrogen or oestrogen is a category of sex hormone responsible for the development and regulation of the female reproductive system and secondary sex characteristics. There are three major endogenous estrogens that have estrogenic hormonal acti ...

receptor not found in mature spermatozoa, causes loss of surface ADAM3 and decreased zona pellucida binding. Other studies have shown ADAM3-/- mouse spermatozoa fail to show sperm-sperm aggregation, although the significance of this is still unknown. ADAM3 has not yet been found in humans.

References

Proteases Semen EC 3.4.24 {{enzyme-stub