Figure 13.

Model for cDhc1b activity in flagellar assembly and maintenance. Transport of IFT particles toward the flagellar tips (the microtubule plus ends) is mediated by FLA10 kinesin II motors (small, paired spheres). Cytoplasmic dynein (large, paired spheres) may be required for the minus-end–directed transport of flagellar components along cytoplasmic microtubules to the base of the flagellum. Alternatively, cytoplasmic dynein may be required to transport IFT particles from the flagellar tip to the flagellar base or for the recycling of IFT particles in the cytoplasm to pick up new components. Although the nature of material transported up the flagellum is unknown, possible components include radial spokes (T-shaped structures), unidentified complexes (large question marks), and/or signaling components involved in regulating flagellar length.