Sticking together a signal

Calautti et al. have taken a collection of proteins that affect cell adhesion in keratinocytes and linked them into a pathway (page 137). The result is a simple sequence from Rho through to the phosphorylation of catenins associated with adherens junctions. But there are hints that reality may be more complex, with more side-branches and collaborations.

During differentiation of keratinocytes these skin cells strengthen their attachment to one another, and both Fyn kinase and Rho are activated. The ultimate effect of activating Rho—phosphorylation of catenins—requires Fyn. Calautti et al. link Rho and Fyn into the same pathway by showing that both activation of Rho and the interaction of Rho with the PRK2 kinase are sufficient and, in the case of Rho, required to turn on Fyn. PRK2, a Rho effector, increases Fyn activity after being...