IZUMO1

IZUMO1 is a protein that in humans is encoded by the IZUMO1 gene. Named after a Japanese shrine dedicated to marriage, IZUMO1 is essential for sperm-egg fusion, a critical step in fertilization.

Function

IZUMO1 is a member of the IZUMO family of proteins. This protein is specifically located in the acrosomal membrane of the sperm head and is required for sperm-egg plasma membrane binding and fusion. The IZUMO1 protein relocates to the equatorial segment after the acrosome reaction and is thought to be involved in the fusion of the sperm and egg membranes.

Structure

The IZUMO1 protein is a type I membrane protein with an extracellular N-terminus and a cytoplasmic C-terminus. The extracellular region contains an immunoglobulin-like (Ig-like) domain, which is thought to be involved in binding to the egg plasma membrane.

Clinical significance

Mutations in the IZUMO1 gene have been associated with infertility in men. Studies have shown that men with mutations in this gene produce sperm that are unable to fuse with the egg, leading to infertility.

See also

• Fertilization
• Sperm-egg fusion
• Acrosome reaction