Ciliary Motility: Regulation of Axonemal Dynein Motors

Ciliary motility is crucial for the development and health of many organisms. Motility depends on the coordinated activity of multiple dynein motors arranged in a precise pattern on the outer doublet microtubules. Although significant progress has been made in elucidating the composition and organization of the dyneins, a comprehensive understanding of dynein regulation is lacking. Here, we focus on two conserved signaling complexes located at the base of the radial spokes. These include the I1/f inner dynein arm associated with radial spoke 1 and the calmodulin-and spoke-associated complex and the nexin-dynein regulatory complex associated with radial spoke 2. Current research is focused on understanding how these two axonemal hubs coordinate and regulate the dynein motors and ciliary motility. Outline 1 Introduction 2 Axonemal structure and a sliding microtubule model for ciliary bending 3 Regulation of axonemal bending by I1/f dynein and the MIA complex located near RS1 4 The RS2 regulatory complex and downstream regulation 5 Conclusion