eLife Assessment
The authors address a fundamental question for cell and tissue biology. They use the skin epidermis as a paradigm and ask how stratifying self-renewing epithelia induce differentiation and upward migration in basal dividing progenitor cells to generate suprabasal barrier-forming cells that are essential for a functional barrier formed by such an epithelium. The authors provide compelling evidence time that an increase in intracellular actomyosin contractility, a hallmark of barrier-forming keratinocytes, is sufficient to trigger terminal differentiation, providing in vivo evidence of the interdependency of cell mechanics and differentiation. To illustrate their points, the authors use a combination of genetic mouse models, RNA sequencing, and immunofluorescence analysis. Precisely how the changes in gene expression, cell morphology, mechanics, and cell position are instructive and whether consecutive changes in differentiation are required still remain unclear, but the paper takes a nice step in advancing our knowledge of the process.