Ephrin-A3 also known as EPH-related receptor tyrosine kinase ligand 3 or EFNA3, is a member of the ephrin family. The Eph family receptor interacting proteins (ephrins) are a family of proteins that serve as the ligands of the Eph receptor, which compose the largest known subfamily of receptor protein-tyrosine kinases (RTKs). Ephrin-A3 and their Eph family of receptor tyrosine kinases are expressed by cells of the SVZ. Ephrin subclasses are further distinguished by their mode of attachment to the plasma membrane: Ephrin-A3 ligands bind EphA receptors and are anchored to the plasma membrane via a glycosylphosphatidylinositol (GPI) linkage, whereas ephrin-B ligands bind EphB receptors and are anchored via a transmembrane domain. Ephrin-A3 expressed on astrocytes activates EphA4 on the post-synaptic neuron and restricts the growth of dendritic spines through multiple pathways.
