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Cby1 promotes Ahi1 recruitment to a ring-shaped domain at the centriole-cilium interface and facilitates proper cilium formation and function.

Lee YL, Santé J, Comerci CJ, Cyge B, Menezes LF, Li FQ, Germino GG, Moerner WE, Takemaru K, Stearns T - Mol. Biol. Cell (2014)

Bottom Line: Defects in centrosome and cilium function are associated with phenotypically related syndromes called ciliopathies.Superresolution microscopy using both three-dimensional SIM and STED reveals that Cby1 localizes to an ∼250-nm ring at the distal end of the mature centriole, in close proximity to Ofd1 and Ahi1, a component of the transition zone between centriole and cilium.This suggests that Cby1 is required for efficient recruitment of Ahi1, providing a possible molecular mechanism for the ciliogenesis defect in Cby1(-/-) cells.

View Article: PubMed Central - PubMed

Affiliation: Department of Biology, Stanford School of Medicine, Stanford University, Stanford, CA 94305.

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Model for localization of centriole/cilium complex proteins and Cby1 function. (A) Representative localizations in Cby1+/+ cells for Ahi1, Cby1, Ofd1, Sdccag8, and Cep164 from superresolution imaging shown on the longitudinal axis of the centriole in the diagram. Localizations on the transverse axis of the centriole are shown in the cutout (XY view). (B) In Cby1−/− cells, levels of centrosomal Ahi1 and ciliary Arl13b are reduced, suggesting that the transition zone is disrupted, resulting in a defect in maintaining ciliary composition.
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Figure 8: Model for localization of centriole/cilium complex proteins and Cby1 function. (A) Representative localizations in Cby1+/+ cells for Ahi1, Cby1, Ofd1, Sdccag8, and Cep164 from superresolution imaging shown on the longitudinal axis of the centriole in the diagram. Localizations on the transverse axis of the centriole are shown in the cutout (XY view). (B) In Cby1−/− cells, levels of centrosomal Ahi1 and ciliary Arl13b are reduced, suggesting that the transition zone is disrupted, resulting in a defect in maintaining ciliary composition.

Mentions: We showed that deletion of Cby1 results in reduced efficiency of primary cilium formation in culture and in cystic kidneys, a cilium-associated defect, in vivo. A possible molecular basis for these effects was revealed by our finding that Cby1 is required for full recruitment of Arl13b to the primary cilium, suggesting a role in determining ciliary protein content. In addition, we showed that the Cby1 protein localizes to a specific compartment at the distal end of the centriole with Ofd1 and Ahi1 and is important for the function of the transition zone between centriole and cilium. The function of Cby1 may be mediated in part by Ahi1, which is reduced at the centrosome of Cby1−/− cells. Given the known functions of these proteins in cilium structure and function (Hsiao et al., 2009; Singla et al., 2010; Lancaster et al., 2011), we propose that the defect in determining ciliary protein content in Cby1−/− cells is due to functional disruption of this domain. We summarize these findings in a model in Figure 8.


Cby1 promotes Ahi1 recruitment to a ring-shaped domain at the centriole-cilium interface and facilitates proper cilium formation and function.

Lee YL, Santé J, Comerci CJ, Cyge B, Menezes LF, Li FQ, Germino GG, Moerner WE, Takemaru K, Stearns T - Mol. Biol. Cell (2014)

Model for localization of centriole/cilium complex proteins and Cby1 function. (A) Representative localizations in Cby1+/+ cells for Ahi1, Cby1, Ofd1, Sdccag8, and Cep164 from superresolution imaging shown on the longitudinal axis of the centriole in the diagram. Localizations on the transverse axis of the centriole are shown in the cutout (XY view). (B) In Cby1−/− cells, levels of centrosomal Ahi1 and ciliary Arl13b are reduced, suggesting that the transition zone is disrupted, resulting in a defect in maintaining ciliary composition.
© Copyright Policy - creative-commons
Related In: Results  -  Collection

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Figure 8: Model for localization of centriole/cilium complex proteins and Cby1 function. (A) Representative localizations in Cby1+/+ cells for Ahi1, Cby1, Ofd1, Sdccag8, and Cep164 from superresolution imaging shown on the longitudinal axis of the centriole in the diagram. Localizations on the transverse axis of the centriole are shown in the cutout (XY view). (B) In Cby1−/− cells, levels of centrosomal Ahi1 and ciliary Arl13b are reduced, suggesting that the transition zone is disrupted, resulting in a defect in maintaining ciliary composition.
Mentions: We showed that deletion of Cby1 results in reduced efficiency of primary cilium formation in culture and in cystic kidneys, a cilium-associated defect, in vivo. A possible molecular basis for these effects was revealed by our finding that Cby1 is required for full recruitment of Arl13b to the primary cilium, suggesting a role in determining ciliary protein content. In addition, we showed that the Cby1 protein localizes to a specific compartment at the distal end of the centriole with Ofd1 and Ahi1 and is important for the function of the transition zone between centriole and cilium. The function of Cby1 may be mediated in part by Ahi1, which is reduced at the centrosome of Cby1−/− cells. Given the known functions of these proteins in cilium structure and function (Hsiao et al., 2009; Singla et al., 2010; Lancaster et al., 2011), we propose that the defect in determining ciliary protein content in Cby1−/− cells is due to functional disruption of this domain. We summarize these findings in a model in Figure 8.

Bottom Line: Defects in centrosome and cilium function are associated with phenotypically related syndromes called ciliopathies.Superresolution microscopy using both three-dimensional SIM and STED reveals that Cby1 localizes to an ∼250-nm ring at the distal end of the mature centriole, in close proximity to Ofd1 and Ahi1, a component of the transition zone between centriole and cilium.This suggests that Cby1 is required for efficient recruitment of Ahi1, providing a possible molecular mechanism for the ciliogenesis defect in Cby1(-/-) cells.

View Article: PubMed Central - PubMed

Affiliation: Department of Biology, Stanford School of Medicine, Stanford University, Stanford, CA 94305.

Show MeSH
Related in: MedlinePlus