The primary cilium as a cellular signaling center: lessons from disease.

Genetic diseases known as ciliopathies have recently entered the limelight, placing new importance on a previously mysterious organelle: the primary cilium. Mutations affecting the primary cilium in both humans and animal models can lead to a plethora of distinct phenotypes including retinal degeneration, kidney cysts, and brain malformations. New findings are quickly lending insight into the functions of this cellular extension that seems to be especially important in modulation of subcellular signaling cascades at various stages of development and adult homeostasis.