Figure 1

ALC localizes to the primary cilium and detects changes in ciliary Ca²⁺ levels. (A) Schematic of primary cilium-localized biosensor, ALC. (B) ALC FRET signal increases when ionomycin is added to media. FRET signal is reported on a pixel-by-pixel basis. Scale bars, 5 μm. (C) Traces of baseline-normalized FRET signal over time with different [CaCl₂]. (D) YPet fluorescence images of a vertical primary cilium which bent during flow. Scale bars, 10 μm. (E , F) Individual ciliary and cytosolic Ca²⁺ measurements during oscillatory fluid flow starting at t = 0 s. (G , H) Percent of viable MLO-Y4 primary cilia and cytosolic domains exhibiting flow-induced Ca²⁺ increases (n = 15–21). (I , J) Flow-induced Ca²⁺ increases normalized to baseline value in the primary cilium and cytosol with untreated or thapsigargin-treated media (untreated (n = 17 or 18), thapsigargin (n = 6)). (K , L) Average peak response over baseline value for cilia and cytosolic domains with thapsigargin treatment for all viable cells (untreated (n = 17 or 18), thapsigargin (n = 6)). Error bars show ±SEM (*p < 0.05).