Act your age: Tuning cell behavior to tissue requirements in interfollicular epidermis

In all tissues the balance of cell proliferation and differentiation needs to be tuned to match the varying requirements of embryonic development and adult life. This is well illustrated by the interfollicular epidermis (IFE), which undergoes expansion and remodeling in utero, significant post natal growth and is then maintained in homeostasis. In addition to sustaining a high daily turnover of cells, the epidermis is able to re-populate areas of tissue damage due to common environmental stresses such as wounding. Here recent insights into proliferating cell behavior in IFE and how this changes through development and into adulthood are discussed.

► Cell behavior is tuned to tissue requirements in embryonic and adult epidermis.
► Embryonic epidermis is characterized by a switch in the orientation of mitosis.
► Adult epidermis is maintained by a single population of progenitor cells.
► In adults quiescent stem cells coexist alongside progenitors.
► Multiple cell types are mobilized to repair injured epidermis.