Under Your Skin

The story of your life is written in every wrinkle and scar on your skin. Beneath that tapestry is a constant balancing act: skin cells 'deciding' to specialise into the protective layers that shield your body, or remain poised to divide when needed. A new study shows that this decision is influenced by two proteins, keratin 14 and keratin 15. Keratin 14 promotes differentiation by restraining a growth signal called YAP1, keeping it out of the nucleus. Keratin 15 does the opposite, allowing YAP1 to stay active in the nucleus and hold cells in a more flexible state. The research found that keratin 15 marks a distinct pool of these cells (red in the human buttock skin section pictured, with differentiated cells above in pink, and keratin 14-rich cells in green). This balance may be key to wound healing, ageing, and diseases where cell growth goes awry, including cancer.

Written by Anthony Lewis

Anthony Lewis

Writer

Ant was the web editor in the early days of BPoD, and has since worked with the UK’s top science organisations as a writer and multimedia producer. He now splits his time between freelance work and managing multimedia at The Lancet.

Website

• Image from work by Catherine J. Redmond and colleagues
• Department of Cell & Developmental Biology, University of Michigan Medical School, Ann Arbor, MI, USA
• Image originally published with a Creative Commons Attribution 4.0 International (CC BY 4.0)
• Published in Journal of Cell Biology, January 2026