The large families of Eph receptor tyrosine kinases and their ephrin ligands transduce
signals in a cell-cell contact-dependent fashion and thereby coordinate the growth,
differentiation, and patterning of almost every organ and tissue. Eph–ephrin interactions can
trigger a wide array of cellular responses, including cell adhesion, boundary formation, and
repulsion. The exact mechanisms leading to this diversity of responses are unclear but
appear to involve differential signaling, proteolytic cleavage of ephrins, and endocytosis of …