Figure 1

Schematic of a primary (non-motile) cilium and intraflagellar transport (IFT). (a) Ciliary cargo proteins, transported from the Golgi network to the basal body, move between the base and the tip of the cilium by IFT. Motor proteins, such as kinesin 2 and dynein 2, associated with IFT complexes, are responsible for movement along axonemal microtubules in an anterograde and retrograde direction, respectively. (b) Schematic diagram of axoneme cross-section. Motile cilia have a 9 + 2 microtubule pair ultrastructure, with inner and outer dynein arms, whereas primary cilia typically have 9 + 0 arrangement, without dynein arms.