Left: Ephrin and Eph receptors are found on the surface of almost all cells. Center: When cells come into contact with each other, the two proteins form a tight complex. This triggers a signaling chain which causes the cell membrane to protrude. This process is controlled by the Tiam and Rac molecules and results in the reformation of the actin cytoskeleton. Right: The cells separate when one cell fully engulfs the ephrin/Eph complex through endocytosis. © MPI of Neurobiology/Gaitanos