Autophagy and primary cilium crosstalk. Summary of the published studies indicating the existence of a bidirectional crosstalk between ciliogenesis and the primary cilium. (a-b) Pampliega et al. show that proteins of the autophagic machinery localize at the primary cilium. In basal conditions, autophagy degrades the ciliary protein intraflagellar transport 20 (IFT20), inhibiting ciliary growth. In addition, when autophagy is induced by serum starvation, ciliogenesis is promoted by a cilium-dependent activation of the Hedgehog pathway. (c) Tang et al. show that ciliogenesis is induced in conditions of serum starvation through autophagy-mediated degradation of the protein oral-facial-digital syndrome 1 (OFD1). (d) Wang et al. work indicates that autophagy and primary cilium reciprocally affect each other: inhibition of ciliogenesis is associated with the activation of mechanistic target of rapamycin (mTOR) and consequently with the inhibition of autophagy. On the other side, a condition of impaired autophagy stimulates the proteasome, which inhibits ciliogenesis. See the main text for additional details.