Figure 4.

The BBSome is required for the cellular responses evoked by the 5-HT_2CR. A: Lack of localization of 5-HT_2CR in cilia (labeled with acetylated α-tubulin [Acyt α-Tub]) in IMCD3 cells. B: Reduced membrane localization of 5-HT_2CR in IMCD3-Bbs1^−/− cells. Bbs1 gene silencing reduces the surface levels of 5-HT_2CR, but not transferrin receptor, in HEK 293 cells by immunostaining and biotin labeling assay (C), followed by Western blotting (D). E and F: Reduced [Ca²⁺]i response to serotonin in IMCD3-Bbs1^−/− cells. Bbs1 gene silencing decreases [Ca²⁺]i response to serotonin (G), but not ATP (H), and reduces the membrane potential evoked by serotonin (I) in HEK 293 cells. *P < 0.01 and **P < 0.0001 vs. control group. Scale bars, 10 μm.