Ephrin receptor tyrosine kinase (Eph receptor (or Eph RTK))

Ephrin receptor tyrosine kinases (**Eph receptors**) constitute the largest known subfamily of receptor tyrosine kinases. They are membrane-bound proteins activated by binding their membrane-bound ephrin ligands on adjacent cells, requiring direct cell-cell contact for activation. The extracellular region contains a conserved ligand-binding domain followed by a cysteine-rich region and two fibronectin type III repeats; intracellularly they possess a juxtamembrane segment with regulatory phosphorylation sites, a catalytic tyrosine kinase domain, a sterile alpha motif (SAM), and PDZ-binding motifs.[1][5] Eph/ephrin signaling is critical during embryonic development—regulating axon guidance, tissue boundary formation, neural crest migration—and continues to play important roles in adult physiology including synaptic plasticity, angiogenesis, stem cell maintenance/differentiation,[1] immune system function,[4] and cancer biology.[9] The system is divided into two main subclasses based on sequence homology—EphA receptors bind glycosylphosphatidylinositol-linked ephrin-A ligands; EphB receptors bind transmembrane ephrin-B ligands—but there is some cross-reactivity among certain members.[3] Dysregulation of these pathways has been implicated in tumorigenesis/metastasis through effects on cell adhesion/migration/invasion,[9] neurodevelopmental disorders via defective axon pathfinding,[8] abnormal angiogenesis contributing to cardiovascular disease,[8] and altered immune responses.[4] *References indicate that "EPH-family kinase" refers not to one protein but rather an entire subfamily comprising at least fourteen human genes/proteins.*

Other names

EPH-family kinaseErythropoietin-producing hepatocellular receptorEph RTKEphA and EphB receptors (subfamilies)Receptor tyrosine kinase family, ephrin type

Drugs targeting this molecule typically act by: - Inhibiting the intracellular tyrosine kinase domain to block downstream signaling pathways involved in cell proliferation, migration, or survival. - Disrupting ligand-receptor interactions at the extracellular domain to prevent activation of bidirectional signaling. - Modulating clustering/oligomerization required for signal propagation.