Fig. 5

Loci containing STIM1, Orai, TRPC1, AQP4, and Vamp2. Results represent 3–8 experiments. a–f The peak radius for each vesicle size distribution in the untreated cell sample is indicated by an arrow and the same mark applied to samples collected during ER depletion and Ca²⁺ readdition. a STIM1 peak at 240 nm, b TRPC1 peak at 200 nm, c cell surface TRPC1 peak at 215 nm, d AQP4 peak at 205 nm. e Vamp2 peak at 205 nm, f cells were fixed but not permeabilized after no treatment (untreated), after Ca²⁺ depletion, or after Ca²⁺ depletion followed by Ca²⁺ readdition. TRPC1 shows a diffuse localization in cells 1 and 2. g Cumulative distribution of TRPC1 loci in samples of untreated cells and cells after ER depletion. The circumference within which loci are found near each filopodium is represented. Loci within 2.7 µm of the filopodia tip are slightly fewer during ER depletion. Statistics on the distances are untreated (mean = 3.27, S.E.M. 0.091 µm, 196 loci) and ER depletion (mean = 3.78, S.E.M. 0.13 µm, 187 loci). The number of particles segmented was closely related to the number of images (N) analyzed, and N was linear with the number of particles recovered within a single treatment (see Additional file 1: Fig. 6A–B)