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Kinesin-13 regulates the quantity and quality of tubulin inside cilia.

Vasudevan KK, Jiang YY, Lechtreck KF, Kushida Y, Alford LM, Sale WS, Hennessey T, Gaertig J - Mol. Biol. Cell (2014)

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.

View Article: PubMed Central - PubMed

Affiliation: Department of Cellular Biology, University of Georgia, Athens, GA 30602;

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Cells lacking both Kin13Bp and Kin13Cp are deficient in multiplication and ciliary functions. (A) Average growth curves of strains grown with or without shaking (three experiments). (B) Average swimming velocity of cells grown with or without shaking (25 measured cells for each strain/condition). Bars represent standard errors. *p < 0.0001. (C, D) Images of swimming paths of live wild-type and 13BC-KO cells recorded for 10 s. (E) Histogram showing average swim speeds of wild-type and 13BC-KO cells that are either untreated or treated with 1 mM IBMX.
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Figure 2: Cells lacking both Kin13Bp and Kin13Cp are deficient in multiplication and ciliary functions. (A) Average growth curves of strains grown with or without shaking (three experiments). (B) Average swimming velocity of cells grown with or without shaking (25 measured cells for each strain/condition). Bars represent standard errors. *p < 0.0001. (C, D) Images of swimming paths of live wild-type and 13BC-KO cells recorded for 10 s. (E) Histogram showing average swim speeds of wild-type and 13BC-KO cells that are either untreated or treated with 1 mM IBMX.

Mentions: Deletions of either KIN13B or KIN13C did not affect the rate of cell multiplication (Figure 2A) or the gross phenotype, except for a mild decrease in the motility rate in the absence of KIN13C (Figure 2B). Kin13Bp and Kin13Cp have a similar domain organization (Figure 1A), and the sequences of their motor domains indicate that they originated from a recent gene duplication (Wickstead et al., 2010). We hypothesized that Kin13Bp and Kin13Cp have partially redundant functions. About half of the homozygotes lacking both Kin13Bp and Kin13Cp (13BC-KO) were viable (Table 1) but grew and swam more slowly than the single knockouts (Figure 2, A–D, Supplemental Figure S3, A–D, and Supplemental Movie S1). A phosphodiesterase inhibitor, IBMX, increases the swim speed of Tetrahymena by increasing the ciliary beat frequency (Hennessey and Lampert, 2012). IBMX (1 mM) increased the swimming rate of the 13BC-KO mutants, but they remained slower than the similarly treated wild-type cells (Figure 2E and Supplemental Movies S2 and S3). The slow cell motility indicates an abnormal function of the locomotory cilia. The 13BC-KO cells also had a reduced rate of phagocytosis, a function that depends on the motility of oral cilia (Supplemental Figure S3E). Shaking of the 13BC-KO flask cultures caused further reduction in the multiplication and motility rates, whereas this treatment had little effect on the wild-type cells (Figure 2, A and B). The phenotypes of some ciliary mutants are enhanced by increased aeration (Brown et al., 2003; Hou et al., 2007), again indicating that Kin13Bp and Kin13Cp affect cilia. Whereas Kin13Cp localized strongly to the CVP, a microtubule-rich organelle involved in osmoregulation (Allen and Naitoh, 2002), we did not detect a change in the sensitivity of 13BC-KO cells to either hypoosmotic or hyperosmotic conditions (unpublished data).


Kinesin-13 regulates the quantity and quality of tubulin inside cilia.

Vasudevan KK, Jiang YY, Lechtreck KF, Kushida Y, Alford LM, Sale WS, Hennessey T, Gaertig J - Mol. Biol. Cell (2014)

Cells lacking both Kin13Bp and Kin13Cp are deficient in multiplication and ciliary functions. (A) Average growth curves of strains grown with or without shaking (three experiments). (B) Average swimming velocity of cells grown with or without shaking (25 measured cells for each strain/condition). Bars represent standard errors. *p < 0.0001. (C, D) Images of swimming paths of live wild-type and 13BC-KO cells recorded for 10 s. (E) Histogram showing average swim speeds of wild-type and 13BC-KO cells that are either untreated or treated with 1 mM IBMX.
© Copyright Policy - creative-commons
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4310739&req=5

Figure 2: Cells lacking both Kin13Bp and Kin13Cp are deficient in multiplication and ciliary functions. (A) Average growth curves of strains grown with or without shaking (three experiments). (B) Average swimming velocity of cells grown with or without shaking (25 measured cells for each strain/condition). Bars represent standard errors. *p < 0.0001. (C, D) Images of swimming paths of live wild-type and 13BC-KO cells recorded for 10 s. (E) Histogram showing average swim speeds of wild-type and 13BC-KO cells that are either untreated or treated with 1 mM IBMX.
Mentions: Deletions of either KIN13B or KIN13C did not affect the rate of cell multiplication (Figure 2A) or the gross phenotype, except for a mild decrease in the motility rate in the absence of KIN13C (Figure 2B). Kin13Bp and Kin13Cp have a similar domain organization (Figure 1A), and the sequences of their motor domains indicate that they originated from a recent gene duplication (Wickstead et al., 2010). We hypothesized that Kin13Bp and Kin13Cp have partially redundant functions. About half of the homozygotes lacking both Kin13Bp and Kin13Cp (13BC-KO) were viable (Table 1) but grew and swam more slowly than the single knockouts (Figure 2, A–D, Supplemental Figure S3, A–D, and Supplemental Movie S1). A phosphodiesterase inhibitor, IBMX, increases the swim speed of Tetrahymena by increasing the ciliary beat frequency (Hennessey and Lampert, 2012). IBMX (1 mM) increased the swimming rate of the 13BC-KO mutants, but they remained slower than the similarly treated wild-type cells (Figure 2E and Supplemental Movies S2 and S3). The slow cell motility indicates an abnormal function of the locomotory cilia. The 13BC-KO cells also had a reduced rate of phagocytosis, a function that depends on the motility of oral cilia (Supplemental Figure S3E). Shaking of the 13BC-KO flask cultures caused further reduction in the multiplication and motility rates, whereas this treatment had little effect on the wild-type cells (Figure 2, A and B). The phenotypes of some ciliary mutants are enhanced by increased aeration (Brown et al., 2003; Hou et al., 2007), again indicating that Kin13Bp and Kin13Cp affect cilia. Whereas Kin13Cp localized strongly to the CVP, a microtubule-rich organelle involved in osmoregulation (Allen and Naitoh, 2002), we did not detect a change in the sensitivity of 13BC-KO cells to either hypoosmotic or hyperosmotic conditions (unpublished data).

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.

View Article: PubMed Central - PubMed

Affiliation: Department of Cellular Biology, University of Georgia, Athens, GA 30602;

Show MeSH
Related in: MedlinePlus