Ca2+/calmodulin-dependent phosphorylation of ciliary beta-tubulin in Tetrahymena

J Biochem. 1989 Jun;105(6):858-60. doi: 10.1093/oxfordjournals.jbchem.a122766.


The ciliary axoneme is the minimal structure responsible for Ca2+-dependent modulation of ciliary movement. We demonstrated that, in Tetrahymena ciliary axonemes, beta-tubulin was exclusively phosphorylated by an endogenous Ca2+/calmodulin-dependent protein kinase(s). The phosphorylation of beta-tubulin also occurred in the outerdoublet microtubule fraction, suggesting that the responsible enzyme(s) was tightly associated with outerciliary motility, Ca2+-dependent phosphorylation of beta-tubulin was also found to occur exclusively. From these results, it is inferable that the phosphorylation of beta-tubulin is involved in Ca2+-dependent ciliary reversal.

MeSH terms

  • Animals
  • Calcium / metabolism*
  • Calmodulin / metabolism*
  • Cilia / metabolism*
  • Iodine Radioisotopes
  • Phosphorylation
  • Tetrahymena / metabolism*
  • Tubulin / metabolism*


  • Calmodulin
  • Iodine Radioisotopes
  • Tubulin
  • Calcium