Ephrin

In molecular biology, ephrins are a family of proteins that are ligands of class V (EPH-related) receptor protein-tyrosine kinases. These receptors and their ligands have been implicated in regulating neuronal axon guidance and in patterning of the developing nervous system and may also serve a patterning and compartmentalisation role outside of the nervous system.

Ephrins are membrane-attached proteins of 205 to 340 residues. Attachment appears to be crucial for their normal function. Type-A ephrins are linked to the membrane via a glycosylphosphatidylinositol (GPI)-linkage, while type-B ephrins are type-I membrane proteins.

Types include:
 * EFNA1
 * EFNA2
 * EFNA3
 * EFNA4
 * EFNA5
 * EFNB1
 * EFNB2
 * EFNB3