8.A.55 The IZUMO Sperm-Egg Fusion Protein 1 (IZUMO1) Family 

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' (Klinovska et al. 2014). Epicatechin (EPC) is a flavonoid catechin, described as a powerful scavenger of a wide spectrum of reactive oxygen species (ROS) and a modulator of ex vivo sperm vitality. It provides protection to spermatozoa exposed to low temperatures (Baňas et al. 2023).


 

References:

Baňas, &.#.3.5.2.;., F. Benko, M. Ďuračka, N. Lukáč, and E. Tvrdá. (2023). Epicatechin Prevents Cryocapacitation of Bovine Spermatozoa through Antioxidant Activity and Stabilization of Transmembrane Ion Channels. Int J Mol Sci 24:.
Inoue, N., D. Hamada, H. Kamikubo, K. Hirata, M. Kataoka, M. Yamamoto, M. Ikawa, M. Okabe, and Y. Hagihara. (2013). Molecular dissection of IZUMO1, a sperm protein essential for sperm-egg fusion. Development 140: 3221-3229.
Klinovska, K., N. Sebkova, and K. Dvorakova-Hortova. (2014). Sperm-egg fusion: a molecular enigma of mammalian reproduction. Int J Mol Sci 15: 10652-10668.
Examples:

TC#NameOrganismal TypeExample
8.A.55.1.1

IZUMO sperm-egg fusion protein 1of 350 aas and 2 TMSs (N- and C-termini). Essential sperm cell-surface protein required for fertilization by acting as a ligand for the IZUMO1R/JUNO receptor on the 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 (Inoue et al. 2013). The ligand-receptor interaction probably does not act as a membrane 'fusogen' (Klinovska et al. 2014).

Animals

IZUMO of Homo sapiens

 
8.A.55.1.2

Uncharacterized protein of 352 aas and 1 or 2 TMSs (N- and C-termini).

Animals

UP of Astyanax mexicanus (Blind cave fish) (Astyanax fasciatus mexicanus)

 
Examples:

TC#NameOrganismal TypeExample
8.A.55.2.1

IZUMO sperm-egg fusion protein 2 of 221 aas and 1 or 2 TMSs.

Animals

IZUMO2 of Homo sapiens

 
8.A.55.2.2

IZUMO3 of 239 aas and 1 C-terminal TMS.

Animals

IZUMO3 of Homo sapiens

 
Examples:

TC#NameOrganismal TypeExample
8.A.55.3.1

IZUMO4 of 232 aas and 1 TMS.

Animals

IZUMO4 of Homo sapiens