EPHB1
Description
The EPHB1 (EPH receptor B1) is a protein-coding gene located on chromosome 3.
Ephrin type-B receptor 1 is a protein that in humans is encoded by the EPHB1 gene. Ephrin receptors and their ligands, the ephrins, mediate numerous developmental processes, particularly in the nervous system. 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 divided into 2 groups based on the similarity of their extracellular domain sequences and their affinities for binding ephrin-A and ephrin-B ligands. Ephrin receptors make up the largest subgroup of the receptor tyrosine kinase (RTK) family. The protein encoded by this gene is a receptor for ephrin-B family members.
Ephrin type-B receptor 1 (EPHB1) is a receptor tyrosine kinase that binds to transmembrane ephrin-B family ligands on neighboring cells, triggering contact-dependent bidirectional signaling. Forward signaling occurs downstream of the receptor, while reverse signaling occurs downstream of the ephrin ligand. EPHB1 interacts with EFNB1, EFNB2, and EFNB3, mediating various developmental processes. During nervous system development, EPHB1 regulates retinal axon guidance, likely through repulsive interactions with EFNB2. In the adult nervous system, EPHB1 and EFNB3 regulate chemotaxis, proliferation, and polarity of hippocampal neural progenitors. EPHB1 also plays a redundant role with other ephrin-B receptors in dendritic spine development and synapse formation. It may also regulate angiogenesis, cell migration, and adhesion. EPHB1 activation by EFNB1, and potentially other ephrin-B ligands, activates MAPK/ERK and JNK signaling cascades to regulate cell migration and adhesion. EPHB1 is involved in maintaining satellite cells (muscle stem cells) by promoting self-renewal and reducing their activation and differentiation. It forms a heterotetramer with its ligand, composed of an ephrin dimer and a receptor dimer, required for inducing biological responses. EPHB1 interacts with EPHB6, transphosphorylates it to form an active signaling complex, and interacts with PICK1. It interacts with NCK1 through Tyr-594, activating the JUN cascade to regulate cell adhesion. Upon ligand activation, it interacts with GRB7 and GRB10 through Tyr-928 and with GRB2 through residues within the catalytic domain. EPHB1 also interacts with GRB2, SHC1, and SRC, activating the MAPK/ERK cascade to regulate cell migration. It interacts with CBL, regulating receptor degradation through ubiquitination, and interacts with ACP1.
EPHB1 is also known as ELK, EPHT2, Hek6, NET.
