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Dopamine receptors reveal an essential role of IFT-B, KIF17, and Rab23 in delivering specific receptors to primary cilia.

Leaf A, Von Zastrow M - Elife (2015)

Bottom Line: This targeting mechanism critically depends on Rab23, a small guanine nucleotide binding protein that has important effects on physiological signaling from cilia but was not known previously to be essential for ciliary delivery of any cargo.Depleting Rab23 prevents dopamine receptors from accessing the ciliary membrane.Dopamine receptors thus reveal a previously unrecognized mechanism of ciliary receptor targeting and functional role of Rab23 in promoting this process.

View Article: PubMed Central - PubMed

Affiliation: Program in Cell Biology, University of California, San Francisco, San Francisco, United States.

ABSTRACT
Appropriate physiological signaling by primary cilia depends on the specific targeting of particular receptors to the ciliary membrane, but how this occurs remains poorly understood. In this study, we show that D1-type dopaminergic receptors are delivered to cilia from the extra-ciliary plasma membrane by a mechanism requiring the receptor cytoplasmic tail, the intraflagellar transport complex-B (IFT-B), and ciliary kinesin KIF17. This targeting mechanism critically depends on Rab23, a small guanine nucleotide binding protein that has important effects on physiological signaling from cilia but was not known previously to be essential for ciliary delivery of any cargo. Depleting Rab23 prevents dopamine receptors from accessing the ciliary membrane. Conversely, fusion of Rab23 to a non-ciliary receptor is sufficient to drive robust, nucleotide-dependent mis-localization to the ciliary membrane. Dopamine receptors thus reveal a previously unrecognized mechanism of ciliary receptor targeting and functional role of Rab23 in promoting this process.

No MeSH data available.


Whole-cell images for corresponding images shown in Figure 6G.The merged images display SSTR3-GFP in green and AcTub in red. Dashed blue line indicates outline of an individual cell. Scale bar, 5 μm.DOI:http://dx.doi.org/10.7554/eLife.06996.033
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fig6s4: Whole-cell images for corresponding images shown in Figure 6G.The merged images display SSTR3-GFP in green and AcTub in red. Dashed blue line indicates outline of an individual cell. Scale bar, 5 μm.DOI:http://dx.doi.org/10.7554/eLife.06996.033

Mentions: To ask if Rab23 affects additional receptor cargoes, we carried out the same experiment investigating ciliary localization of SSTR3. Duplexes were transfected individually into IMCD3 cells stably expressing SSTR3-GFP. Rab23 knockdown significantly reduced ciliary targeting of SSTR3, as assessed by epifluorescence microscopy and both quantitative metrics (Figure 6G–I; whole-cell images shown in Figure 6—figure supplement 4).


Dopamine receptors reveal an essential role of IFT-B, KIF17, and Rab23 in delivering specific receptors to primary cilia.

Leaf A, Von Zastrow M - Elife (2015)

Whole-cell images for corresponding images shown in Figure 6G.The merged images display SSTR3-GFP in green and AcTub in red. Dashed blue line indicates outline of an individual cell. Scale bar, 5 μm.DOI:http://dx.doi.org/10.7554/eLife.06996.033
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4547097&req=5

fig6s4: Whole-cell images for corresponding images shown in Figure 6G.The merged images display SSTR3-GFP in green and AcTub in red. Dashed blue line indicates outline of an individual cell. Scale bar, 5 μm.DOI:http://dx.doi.org/10.7554/eLife.06996.033
Mentions: To ask if Rab23 affects additional receptor cargoes, we carried out the same experiment investigating ciliary localization of SSTR3. Duplexes were transfected individually into IMCD3 cells stably expressing SSTR3-GFP. Rab23 knockdown significantly reduced ciliary targeting of SSTR3, as assessed by epifluorescence microscopy and both quantitative metrics (Figure 6G–I; whole-cell images shown in Figure 6—figure supplement 4).

Bottom Line: This targeting mechanism critically depends on Rab23, a small guanine nucleotide binding protein that has important effects on physiological signaling from cilia but was not known previously to be essential for ciliary delivery of any cargo.Depleting Rab23 prevents dopamine receptors from accessing the ciliary membrane.Dopamine receptors thus reveal a previously unrecognized mechanism of ciliary receptor targeting and functional role of Rab23 in promoting this process.

View Article: PubMed Central - PubMed

Affiliation: Program in Cell Biology, University of California, San Francisco, San Francisco, United States.

ABSTRACT
Appropriate physiological signaling by primary cilia depends on the specific targeting of particular receptors to the ciliary membrane, but how this occurs remains poorly understood. In this study, we show that D1-type dopaminergic receptors are delivered to cilia from the extra-ciliary plasma membrane by a mechanism requiring the receptor cytoplasmic tail, the intraflagellar transport complex-B (IFT-B), and ciliary kinesin KIF17. This targeting mechanism critically depends on Rab23, a small guanine nucleotide binding protein that has important effects on physiological signaling from cilia but was not known previously to be essential for ciliary delivery of any cargo. Depleting Rab23 prevents dopamine receptors from accessing the ciliary membrane. Conversely, fusion of Rab23 to a non-ciliary receptor is sufficient to drive robust, nucleotide-dependent mis-localization to the ciliary membrane. Dopamine receptors thus reveal a previously unrecognized mechanism of ciliary receptor targeting and functional role of Rab23 in promoting this process.

No MeSH data available.