Cilia functions in development

Recent advances in developmental genetics and human disease gene cloning have highlighted the essential roles played by cilia in developmental cell fate decisions, left-right asymmetry, and the pathology of human congenital disorders. Hedgehog signaling in sensory cilia illustrates the importance of trafficking receptors to the cilia membrane (Patched and Smoothened) and the concept of cilia 'gatekeepers' that restrict entry and egress of cilia proteins (Suppressor of fused: Gli complexes). Cilia-driven fluid flow in the embryonic node highlights the role of motile cilia in both generation and detection of mechanical signals in development. In this brief review I select examples of recent studies that have clarified and consolidated our understanding of the role of cilia in development.