Cilia self-organize in response to planar cell polarity and flow

Cilia drive fluid flow in development and physiology, but this requires that all cilia in a tissue orient the same way. Earlier studies indicated that both planar cell polarity (PCP) signalling and cilia-generated fluid flows could influence ciliary orientation. We now learn how asymmetric localization of PCP proteins influences the position and orientation of cilia to control the direction of flow.