Fig. 7. Schematic outlining the myoepithelial cell differentiation program and the contribution of MECs to the salivary gland during homeostatic and regenerative states.

A p63 expressing cells give rise to SMA⁺/p63⁺ double positive MECs, which further differentiate into SMA⁺/p63⁻ MECs. B Structure of the salivary gland and cell markers that represent the various cell types that comprise the salivary gland. C During homeostasis the myoepithelial cells are bipotent and maintain their own lineage (MECs) and the ductal cell lineage. Deletion of ΔNp63 in the MECs leads to altered cellular differentiation and plasticity and a failure in MEC renewal. D After severe injury, SMA positive cells undergo a bipotency to multipotency switch and contribute to the ductal and acinar cell populations. This process is ΔNp63 independent.