sentences:  Displaying similar utility, different ephrins incorporate similar mechanistic pathways to supplement growth of different structures.The ephrin protein family of class A and class B guides ligands with the EphB family cell-surface receptors to provide a steady, ordered, and specific migration of the intestinal epithelial cells from the crypt to villus.The Wnt protein triggers expression of the EphB receptors deep within the crypt, leading to decreased Eph expression and increased ephrin ligand expression, the more superficial a progenitor cell's placement.