A conserved CaM- and radial spoke associated complex mediates regulation of flagellar dynein activity

J Cell Biol. 2007 Nov 5;179(3):515-26. doi: 10.1083/jcb.200703107. Epub 2007 Oct 29.

Abstract

For virtually all cilia and eukaryotic flagella, the second messengers calcium and cyclic adenosine monophosphate are implicated in modulating dynein- driven microtubule sliding to regulate beating. Calmodulin (CaM) localizes to the axoneme and is a key calcium sensor involved in regulating motility. Using immunoprecipitation and mass spectrometry, we identify members of a CaM-containing complex that are involved in regulating dynein activity. This complex includes flagellar-associated protein 91 (FAP91), which shares considerable sequence similarity to AAT-1, a protein originally identified in testis as an A-kinase anchor protein (AKAP)- binding protein. FAP91 directly interacts with radial spoke protein 3 (an AKAP), which is located at the base of the spoke. In a microtubule sliding assay, the addition of antibodies generated against FAP91 to mutant axonemes with reduced dynein activity restores dynein activity to wild-type levels. These combined results indicate that the CaM- and spoke-associated complex mediates regulatory signals between the radial spokes and dynein arms.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Axoneme / metabolism
  • Calcium / metabolism
  • Calmodulin / chemistry*
  • Cell Movement
  • Chlamydomonas reinhardtii / metabolism*
  • Dyneins / chemistry*
  • Dyneins / metabolism
  • Flagella / chemistry*
  • Flagella / metabolism
  • Immunoprecipitation
  • Mass Spectrometry
  • Microtubules / metabolism
  • Microtubules / physiology*
  • Models, Biological
  • Mutation
  • Peptides / chemistry
  • Tissue Distribution

Substances

  • Calmodulin
  • Peptides
  • Dyneins
  • Calcium