ABSTRACT
This chapter examines overview three-dimensional conformation and molecular arrangement of axonemal dyneins in cilia, mostly based on cryo- electron microscope studies and discusses how axonemal dynein creates force and bending motion occurs. The sequences of axonemal dyneins are highly homologous to that of cytoplasmic dyneins at the motor domain, while the N-terminal tail is diverse. Axonemal dyneins are located on microtubule doublets. Axonemal dyneins are anchored on microtubule doublets of the axoneme and their powerstrokes are integrated to generate well-orchestrated ciliary beating. The ciliary doublet, which must be stable during beating motion, maintains unique structures. The motor domains of an outer arm dynein are packed in a compact form in cilia, while they come apart when separated from the microtubule. The basal body structure is indispensable for understanding of ciliogenesis and cilia maintenance, but also necessary to know if the microtubule structure at the basal body is relevant to the waveform as proposed in some models.
