Structural diversity and unity amongst axonemal dynein assembly factors

The essential beating motion of cilia is powered by large multi-subunit complexes called axonemal dynein arms, which are synthesised through a dedicated assembly pathway. Dynein arm assembly is shepherded by nineteen axonemal dynein assembly factors (DNAAFs), which operate in an intricate chaperone relay to promote the protein folding and assembly of individual dynein arm subunits into functional motor complexes in the cytoplasm, followed by their transport into motile cilia. Genetic variants that block the assembly pathway underlie cilia-related human pathologies, including the multi-organ motile ciliopathy called primary ciliary dyskinesia. This structure-focused Perspective summarises recent progress on the DNAAFs and spotlights their emerging roles as important players in the biology of motile cilia.