Figure 2. Schematic representation of the limbal epithelial crypt. The extracellular matrix composition and structure may regulate limbal stem cell fate providing information about their position. Depending on the position of cells at the limbal epithelial crypt, the orientation of the mitotic axis during asymmetric cell division of limbal stem cells could be either vertical or horizontal. An asymmetric dividing stem cell would give rise to another stem cell and a transient amplifying basal cell that would migrate to the peripheral cornea when division occurs in the horizontal axis. Conversely, the stem cell could originate another stem cell and a limbal suprabasal differentiated cell when division takes place following the vertical axis; in this case, loss of contact between one of the daughter cells and the basement membrane would determine the initiation of the differentiation process. White arrows indicate the movement of cells after commitment. Differentiation leads to the expression of the terminal phenotype.