Common Checkpoint

The defining features of stem cells is their potential to develop into multiple cell types and their ability to self-renew. This self-renewal capacity ensures the maintenance of stem cell reservoirs in the body and, if scientists can harness it effectively, in the laboratory too. When maintaining stem cell cultures in the lab, scientists typically use different concoctions of factors specific to the different types of stem cells. But recent research has identified a common checkpoint protein – the regulatory kinase GSK3 – that, when inhibited, maintains self-renewal capacity in multiple stem cell types across multiple species. Indeed, GSK3 inhibition allowed the mouse epiblasts and embryonic stem cells, pictured (green and red), to be cultured together and yet maintain their individual identities – hitherto impossible. In addition to improving stem cell culture techniques, the discovery of the common GSK3 checkpoint could possibly be leveraged clinically to improve the health and healing of ageing tissues.

Written by Ruth Williams

Ruth Williams

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Ruth is a freelance science journalist based in the US. She's a regular correspondent for The Scientist, and her work has appeared in The Lancet, Nature, Scientific American Mind, BBC Focus and elsewhere. Twitter @rooph

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• Image by Duo Wang/Ying Lab/USC Stem Cell. Paper by Duo Wang and Xiukun Wang, and colleagues
• Eli and Edythe Broad Center for Regenerative Medicine and Stem Cell Research at USC, Keck School of Medicine, USC, Los Angeles, CA; Epigenetics and RNA Biology Laboratory, National Institute of Environmental Health Sciences, Durham, NC, USA
• Image copyright held by the original authors
• Published in Cell Research, April 2026