The Function And Signal Transduction Pathway Of EphB2 Receptor

Eph receptors are the largest known family of receptor tyrosine kinases. The Eph receptors and their membrane-attached ligands,the ephrins,show diverse expression patterns during development.Functional studies have demonstrated that Eph receptors and ephrins play important roles in many developmental processes including formation of neuronal network,patterning of neural tube and paraxial mesoderm, guidance of cell migration and axon pathfmding,and vascular formation.Recent studies have also suggested that Eph receptors and ephrins may be involved in carcinogenesis.It is therefore of clinical importance to further. analyze the function of these molecules,particularly their function in tumor cell growth,since manipulation of the activities of these molecules may have therapeutic applications.EphB2 was isolated as a new member of Eph subfamily in 1994 by Kiyokawa from a human gastric cancer cDNA library.Northern blot analysis showed that EphB2 was expressed at higher levels in various tumors of epithelial origin than in corresponding normal tissues. The molecular mechanism by which the EphB2 receptor signaling is propagated, and transmitted remains to be elucidated.The goal of this study is to identify regulatory proteins of EphB2,which can physically interact and regulate the activities of EphB2.To accomplish this goal, we firstly cloned and expressed two extracelluar domains of EphB2 that are related with EphB2 binding to its ligand. Total RNA was isolated from a human...