Figure 5.
Immotile cilia at the periphery of the node sense nodal flow. Ciliated cells located in the central region of the node of the mouse embryo (green) possess motile cilia that rotate and generate nodal flow, whereas those located peripherally (pink) possess immotile cilia that sense the flow. Sensing of the flow requires a Pkd2-Pkd1l1 complex with Ca2+ channel activity that is localized to the cilium. The flow-mediated signal, the identity of which remains unknown, triggers the degradation of Cerl2 mRNA preferentially on the left side.