Axonemal dynein preassembly

Axonemal dyneins are gigantic motor enzymes indispensable for proper ciliary and flagellar motility in eukaryotes including Chlamydomonas. These axonemal dyneins convert the chemical energy of ATP to mechanical force to drive ciliary beating. Here we describe discoveries made using Chlamydomonas that first revealed the complex pathways through which axonemal dyneins are preassembled in the cytoplasm, transported into ciliary/flagellar compartments, and docked onto axonemes, and we summarize current information on the many axonemal dynein assembly factors involved in these processes. In addition, we discuss both similarities and differences between dynein assembly mechanisms in Chlamydomonas compared with other eukaryotes that have motile cilia, explore unexpected links between dynein preassembly and human diseases that were revealed through research using Chlamydomonas, and highlight remaining questions about axonemal dynein assembly mechanisms that may be solved through further studies using this model organism.