Actin up for Hippo

The Hippo (Hpo) signalling pathway is an evolutionarily conserved pathway controlling tissue growth, but its upstream inputs remain poorly understood. In this issue of The EMBO Journal, Sansores-Garcia et al (2011) report that modulation of filamentous (F)-actin accumulation controls Hpo pathway activity. In a related study, Garcia-Fernandez et al (2011) confirm this finding, and also show that the Hpo pathway itself can modulate F-actin levels. Such actin-dependent regulation of Hpo pathway activity has relevance to the control of tissue growth by epithelial architecture and external tension cues.