Kinesin-13 regulates the quantity and quality of tubulin inside cilia.
Bottom Line: Loss of both Kin13Bp and Kin13Cp resulted in slow cell multiplication and motility, overgrowth of cell body microtubules, shortening of cilia, and synthetic lethality with either paclitaxel or a deletion of MEC-17/ATAT1, the α-tubulin acetyltransferase.The mutant cilia beat slowly and axonemes showed reduced velocity of microtubule sliding.Thus kinesin-13 positively regulates the axoneme length, influences the properties of ciliary tubulin, and likely indirectly, through its effects on the axonemal microtubules, affects the ciliary dynein-dependent motility.
Affiliation: Department of Cellular Biology, University of Georgia, Athens, GA 30602;Show MeSH
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Mentions: When the wild-type and 13BC-KO cells were analyzed side by side by immunofluorescence using anti–α-tubulin antibodies, the 13BC-KO cells showed an increased signal of tubulin in the cell bodies (Figure 4A, left). The organization of cortical microtubules seemed normal, except that some of the microtubule types were excessively long. Whereas in the wild-type cells, the CVP rootlets are limited to the vicinity of the CVP rings within two ciliary rows, in the 13BC-KO cells, the same microtubules were exceptionally long, covering almost the entire posterior region of the cell (Figure 4A, left and middle). The mutant transverse microtubule bundles were slightly but significantly longer (Figure 4, A, middle, and B). We conclude that Kin13Bp and Kin13Cp function in the shortening of subtypes of cortical microtubules. In the cell body, the consequences of the absence of kinesin-13 can be explained by its canonical activity as a microtubule-end depolymerizer.
Affiliation: Department of Cellular Biology, University of Georgia, Athens, GA 30602;