ephrinB2

Ephrin-B2, encoded by the EFNB2 gene, is a transmembrane ligand of the ephrin-B family that binds to Eph receptor tyrosine kinases, especially the EphB subclass. It participates in bidirectional signaling, because stimulation of the Eph receptor activates forward signaling in the receptor-expressing cell while triggering reverse signaling in the ephrin-expressing cell.

Ephrin-B2 is expressed in arterial endothelial cells and, through interaction with EphB receptors on neighboring cells, contributes to arterial-venous differentiation and vascular remodeling during development. Genetic disruption of ephrin-B2 signaling in animal models causes defects in vascular patterning and often embryonic lethality, underscoring its essential role in cardiovascular development.

Beyond the vasculature, ephrin-B2 has functions in the nervous system, where it participates in axon guidance and synapse organization. It also influences processes such as cell adhesion and migration in various tissues through bidirectional signaling.

Clinically, the Eph-ephrin pathway is studied as a target for cancer therapy and tissue regeneration, given its role in angiogenesis and cell movement. Alterations in EFNB2 signaling have been linked to tumor progression in some contexts, making ephrin-B2 a subject of ongoing research.

Structurally, ephrin-B2 is a type I membrane protein with a cytoplasmic tail that can be phosphorylated and interact with intracellular adaptors, enabling reverse signaling. Its signaling is regulated by tyrosine phosphorylation and interactions with PDZ-domain proteins, among others.

Ephrin-B2 belongs to a conserved family found across vertebrates, reflecting its fundamental roles in development and tissue organization.