Zonadhesin; Binds in a species-specific manner to the zona pellucida of the egg. May be involved in gamete recognition and/or signaling.

Sperm acrosome membrane-associated protein 1; Plays a role in acrosome expansion and establishment of normal sperm morphology during spermatogenesis (By similarity). Important for male fertility.

Sperm acrosome membrane-associated protein 3, processed form; Sperm surface membrane protein that may be involved in sperm- egg plasma membrane adhesion and fusion during fertilization. It could be a potential receptor for the egg oligosaccharide residue N- acetylglucosamine, which is present in the extracellular matrix over the egg plasma membrane. The processed form has no detectable bacteriolytic activity in vitro.

Izumo sperm-egg fusion protein 1; Essential sperm cell-surface protein required for fertilization by acting as a ligand for IZUMO1R/JUNO receptor on egg. The IZUMO1:IZUMO1R/JUNO interaction is a necessary adhesion event between sperm and egg that is required for fertilization but is not sufficient for cell fusion. The ligand- receptor interaction probably does not act as a membrane 'fusogen'.

Hyaluronidase PH-20; Involved in sperm-egg adhesion. Upon fertilization sperm must first penetrate a layer of cumulus cells that surrounds the egg before reaching the zona pellucida. The cumulus cells are embedded in a matrix containing hyaluronic acid which is formed prior to ovulation. This protein aids in penetrating the layer of cumulus cells by digesting hyaluronic acid; Belongs to the glycosyl hydrolase 56 family.

Processed zona pellucida sperm-binding protein 1; Component of the zona pellucida, an extracellular matrix surrounding oocytes which mediates sperm binding, induction of the acrosome reaction and prevents post-fertilization polyspermy. The zona pellucida is composed of 3 to 4 glycoproteins, ZP1, ZP2, ZP3, and ZP4. ZP1 ensures the structural integrity of the zona pellucida.

Outer dense fiber protein 1; Component of the outer dense fibers (ODF) of spermatozoa. ODF are filamentous structures located on the outside of the axoneme in the midpiece and principal piece of the mammalian sperm tail and may help to maintain the passive elastic structures and elastic recoil of the sperm tail.

Izumo sperm-egg fusion protein 4; IZUMO family member 4; Belongs to the Izumo family.

Testis-specific serine/threonine-protein kinase 4; Serine/threonine kinase which is involved in male germ cell development and in mature sperm function (By similarity). May be involved in the Cre/Creb signaling pathway (By similarity). Phosphorylates CREB1 on 'Ser-133' in vitro and can stimulate Cre/Creb pathway in cells. Phosphorylates CREM on 'Ser-116' in vitro (By similarity). Phosphorylates ODF2 on 'Ser-95' (By similarity). Belongs to the protein kinase superfamily. CAMK Ser/Thr protein kinase family.