Regulation of mitotic spindle orientation during epidermal stratification.

The epidermis is a stratified epithelium that serves as a barrier to infection from environmental pathogens and prevents water loss. Epidermal stratification is tightly controlled during embryogenesis. Progenitor cells in the developing epidermis undergo both symmetric and asymmetric cell divisions to balance the growth of the skin surface area against the generation of differentiated cell layers. Therefore, understanding the relationship between oriented divisions of progenitor cells and the development and stratification of the epidermis is of paramount importance in the field of skin biology and pathology. We provide here an integrated view of recent studies implicating that improper orientation of the mitotic spindle contributes to disorders associated with abnormal epidermal stratification and suggesting that spindle orientation could serve as a potential therapeutic target in skin diseases.