Wnt signaling in polycystic kidney disease.

Wnt signaling cascades activate morphogenetic programs that range from cell migration and proliferation to cell fate determination and stem cell renewal. These pathways enable cells to translate environmental cues into the complex cellular programs that are needed to organize tissues and build organs. Wnt signaling is essential for renal development; however, the specific molecular underpinnings involved are poorly understood. Recent research has revealed an unexpected intersection between Wnt signaling and polycystic kidney disease. Some polycystic kidney disease proteins, such as Inversin and Bardet-Biedl syndrome family members, were found to use components of the Wnt signaling cascade to orient cells along a secondary polarity axis within the plane of the epithelium. These spatial cues may be needed to position nascent tubules with a defined geometry.