Ephrin A3

Ephrin A3 is a member of the ephrin A family of receptor ligands. Ephrins are a class of transmembrane proteins that bind to Eph receptors, a family of receptor tyrosine kinases. These interactions mediate cell-cell communication involved in a variety of developmental processes, including axon guidance, cell migration, tissue boundary formation, and angiogenesis.

Ephrin A3 is a glycosylphosphatidylinositol (GPI)-anchored protein, meaning it is attached to the cell membrane via a GPI anchor rather than a transmembrane domain. This GPI linkage restricts ephrin A3 to the cell surface and allows it to interact with Eph receptors located on adjacent cells.

The ephrin A family generally binds to EphA receptors. Ephrin A3 specifically interacts with several EphA receptors, including EphA3, EphA4, EphA5, EphA6, EphA7, and EphA8. Upon binding, the Eph receptor and ephrin ligand cluster together, leading to bidirectional signaling. This means that signals are transduced in both the Eph-expressing and ephrin-expressing cells.

Ephrin A3 plays a role in several developmental processes, particularly in the nervous system. It is involved in axon guidance, where it helps guide growing axons to their correct targets. It also participates in the formation of topographic maps in the brain. Disruption of ephrin A3 function can lead to developmental abnormalities.

In addition to its role in development, ephrin A3 has also been implicated in cancer. It has been shown to be upregulated in some types of cancer, where it can promote tumor growth, angiogenesis, and metastasis. Its role in cancer is complex and can vary depending on the specific cancer type.