Building a radial spoke: Flagellar Radial Spoke Protein 3 (RSP3) is a dimer

Maureen Wirschell, Feifei Zhao, Chun Yang, Pinfen Yang, Dennis Diener, Anne Gaillard, Joel L. Rosenbaum, Winfield S. Sale

Research output: Contribution to journalArticlepeer-review

36 Scopus citations


Radial spokes are critical multisubunit structures required for normal ciliary and eukaryotic flagellar motility. Experimental evidence indicates the radial spokes are mechanochemical transducers that transmit signals from the central pair apparatus to the outer doublet microtubules for local control of dynein activity. Recently, progress has been made in identifying individual components of the radial spoke, yet little is known about how the radial spoke is assembled or how it performs in signal transduction. Here we focus on radial spoke protein 3 (RSP3), a highly conserved AKAP located at the base of the radial spoke stalk and required for radial spoke assembly on the doublet microtubules. Biochemical approaches were taken to further explore the functional role of RSP3 within the radial spoke structure and for control of motility. Chemical crosslinking, native gel electrophoresis, and epitope-tagged RSP3 proteins established that RSP3 forms a dimer. Analysis of truncated RSP3 proteins indicates the dimerization domain coincides with the previously characterized axoneme binding domain in the N-terminus. We propose a model in which each radial spoke structure is built on an RSP3 dimer, and indicating that each radial spoke can potentially localize multiple PKAs or AKAP-binding proteins in position to control dynein activity and flagellar motility.

Original languageEnglish
Pages (from-to)238-248
Number of pages11
JournalCell Motility and the Cytoskeleton
Issue number3
StatePublished - Mar 2008
Externally publishedYes


  • AKAP
  • Cilia
  • Dynein
  • Flagella
  • Radial spokes


Dive into the research topics of 'Building a radial spoke: Flagellar Radial Spoke Protein 3 (RSP3) is a dimer'. Together they form a unique fingerprint.

Cite this