Keeping a stiff upper lip: p120ctn and tissue fusion.

In this issue, Teng et al. (https://doi.org/10.1083/jcb.202503070) use genome editing, classical tissue-specific gene knockouts, and live cell imaging to show that the interaction of p120ctn with the juxtamembrane domain of classical cadherins is necessary for tissue integrity during the cellular zippering required for upper lip formation in mammals.