The study published in Nature Cell Biology by Wellcome Trust Sanger Institute and the University of Cambridge discovered that skin cells can flip between two states, an expanding state and a balanced state. In the balanced state, the skin cells divide to produce an equal number of dividing and non-dividing cells whereas in the expanding state the skin cells divide to produce a greater number of dividing cells than non-dividing ones. According to Dr. Jones, the senior author of this study, “this research demonstrates that dividing human skin cells can switch their behavior between these two modes of maintenance or repair, challenging the longstanding view that skin renewal and healing relies on a special population of stem cells."
For this study the researchers made videos of more than 3,000 skin cells dividing in culture. They showed that single cells divided in the expanding mode until they produced a multi-layered sheet of cells after which they flip into the balanced mode. They also found that these states are reversible and when a signaling protein ROCK2 kinase is inhibited, it prevents the cells in their repair mode to switch back into their maintenance mode. This finding is significant for cancer research since this could potentially prove as a mechanism by which cancers could arise.
References:
Roshan, A. et al. Human keratinocytes have two interconvertible modes of proliferation. Nat. Cell Biol. (2015). doi:10.1038/ncb3282