EFNA5

Ephrin-A5, a member of the ephrin gene family, prevents axon bundling in cocultures of cortical neurons with astrocytes, a model of late stage nervous system development and differentiation. The EPH and EPH-related receptors comprise the largest subfamily of receptor protein-tyrosine kinases and have been implicated in mediating developmental events, particularly in the nervous system. EPH receptors typically have a single kinase domain and an extracellular region containing a Cys-rich domain and 2 fibronectin type III repeats. The ephrin ligands and receptors have been named by the Eph Nomenclature Committee (1997). Based on their structures and sequence relationships, ephrins are divided into the ephrin-A (EFNA) class, which are anchored to the membrane by a glycosylphosphatidylinositol linkage, and the ephrin-B (EFNB) class, which are transmembrane proteins. The Eph family of receptors are similarly divided into 2 groups based on the similarity of their extracellular domain sequences and their affinities for binding ephrin-A and ephrin-B ligands. [provided by RefSeq, Jul 2008]

Full Name

Ephrin A5

Research Area

Cell surface GPI-bound ligand for Eph receptors, a family of receptor tyrosine kinases which are crucial for migration, repulsion and adhesion during neuronal, vascular and epithelial development. Binds promiscuously Eph receptors residing on adjacent cells, leading to contact-dependent bidirectional signaling into neighboring cells. The signaling pathway downstream of the receptor is referred to as forward signaling while the signaling pathway downstream of the ephrin ligand is referred to as reverse signaling. Induces compartmentalized signaling within a caveolae-like membrane microdomain when bound to the extracellular domain of its cognate receptor. This signaling event requires the activity of the Fyn tyrosine kinase. Activates the EPHA3 receptor to regulate cell-cell adhesion and cytoskeletal organization. With the receptor EPHA2 may regulate lens fiber cells shape and interactions and be important for lens transparency maintenance. May function actively to stimulate axon fasciculation. The interaction of EFNA5 with EPHA5 also mediates communication between pancreatic islet cells to regulate glucose-stimulated insulin secretion. Cognate/functional ligand for EPHA7, their interaction regulates brain development modulating cell-cell adhesion and repulsion.

Biological Process

Axon guidance Source: GO_Central
Ephrin receptor signaling pathway Source: UniProtKB
Negative regulation of substrate adhesion-dependent cell spreading Source: MGI
Nervous system development Source: ProtInc
Positive regulation of peptidyl-tyrosine phosphorylation Source: UniProtKB
Positive regulation of protein phosphorylation Source: BHF-UCL
Regulation of actin cytoskeleton organization Source: UniProtKB
Regulation of cell-cell adhesion Source: UniProtKB
Regulation of cell morphogenesis Source: MGI
Regulation of focal adhesion assembly Source: UniProtKB
Regulation of GTPase activity Source: UniProtKB
Regulation of insulin secretion involved in cellular response to glucose stimulus Source: UniProtKB
Regulation of microtubule cytoskeleton organization Source: UniProtKB

Cellular Location

Cell membrane; Caveola. Compartmentalized in discrete caveolae-like membrane microdomains.