Fig 8. The cnk11-1 mutant has increased tubulin turnover at the flagellar tip.

At least 100 flagella from each strain were measured to determine the average flagellar length. Error bars represent standard deviation of the mean. (A) Flagellar lengths of wild-type (CC-125, green circles) and cnk11-1 (blue triangles) cells before and after deflagellation by pH shock. (B) Cells that carry HA-α-tubulin were mated to cells of opposite mating type that have the corresponding genotype for 30, 60, and 90 minutes before fixation. Flagellar lengths were measured from the non HA-tagged parental strain in mating of wild-type x wild-type (CC-124, magenta), cnk11-1 x cnk11-1 (blue), tpg1 x tpg1 (purple), and cnk11-1; tpg1 x cnk11-1; tpg1 (black). The length of new HA-α-tubulin incorporation (green) was measured at the distal end of the flagella. Insert, a representative image of a cnk11-1 quadriflagellate cells (QFCs) 60 minutes after mating. (C) Flagellar lengths of wild-type (CC-125, green), cnk11-1 (blue), tpg1 (purple), and cnk11-1; tpg1 (black) before and 30 minutes after IBMX treatment. (D) A model of flagellar length regulation by paclitaxel (magenta), polyglutamylation (blue), and CNK11 (green). In short flagella mutants caused by multiple dynein deficiency, addition of paclitaxel and reduction of polyglutamylation, as well as blockage of CNK11, leads to longer flagella, presumably due to stabilized axonemal microtubules. In the CCDC39 and CCDC40 short flagella mutants, addition of paclitaxel and blockage of CNK11 lead to longer flagella. However, reduced polyglutamylation enhances the mutant phenotype and cause increased number of aflagellated cells.