Regulation of the Hippo pathway by cell architecture and mechanical signals.

The Hippo signaling pathway is an evolutionarily conserved mediator of growth control, cell fate decisions and stem cell identity. At the heart of the pathway is a kinase cascade that is reminiscent of other signaling pathways, but recent studies indicate that the Hippo pathway is unique in that it is regulated by cellular architecture and the mechanical properties of the environment. The Hippo pathway may thus serve as a sensor of tissue structure and mechanical tension, integrating information regarding the size and shape of an organ into cellular behavior, such as whether or not to proliferate. In this review we summarize recent discoveries regarding the regulation of the Hippo pathway by cellular polarity, cell junctions, and the cytoskeleton and discuss how these data inform the study of development and disease.