EphA

EphA receptors are receptor tyrosine kinases that bind cell-surface ephrin ligands on adjacent cells and mediate contact-dependent bidirectional signaling^[1]. Mechanistically, EphA/ephrin-A signaling regulates cell adhesion, positioning, migration, and cytoskeletal organization, linking receptor activation to developmental patterning and adult tissue homeostasis^[1][2]. In cancer models, EphA2 shows a key isoform-specific distinction: ephrin-A1 activation inhibits chemotactic migration of glioma and prostate cancer cells, whereas EphA2 overexpression promotes migration in a ligand-independent manner through Akt-dependent Ser897 phosphorylation^[3]. Compared with related EphA isoforms, EphA4 is strongly defined by axon-guidance biology, where activated EphA4 recruits α2-chimaerin to mediate growth-cone collapse and neuronal circuit formation^[4]. For experimental applications, EphA2 ligands, agonistic antibodies, blocking antibodies, and kinase inhibitors can separate canonical ligand-dependent signaling from noncanonical ligand-independent signaling in cancer-cell migration, invasion, vascular-permeability, and tumor-model studies^[3][5][6]. - EphA biology centers on contact-dependent ephrin signaling, cytoskeletal control, and cell-position regulation. - EphA2 research should distinguish ligand-activated suppression from ligand-independent Akt-linked migration. - EphA4 provides a mechanistically distinct axon-guidance model through α2-chimaerin signaling.