Ca2+/calmodulin-dependent phosphorylation of ciliary beta-tubulin in Tetrahymena.
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.
Institute of Biological Sciences, University of Tsukuba, Ibaraki.
J
J
Hirano-Ohnishi
Y
Y
Watanabe
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002147:Calmodulin / Q000378:metabolism*; D002923:Cilia / Q000378:metabolism*; D007457:Iodine Radioisotopes; D010766:Phosphorylation; D013768:Tetrahymena / Q000378:metabolism*; D014404:Tubulin / Q000378:metabolism*
D002147:Calmodulin; D007457:Iodine Radioisotopes; D014404:Tubulin; D002118:Calcium