Figure 2.

G-CatchER⁺ ER localization and HILO imaging leads to quantitative measurement of calcium responses

(A) G-CatchER⁺ expression at 488 nm (green), ER-Tracker red staining at 555 nm (orange), DAPI staining for the nucleus at 405 nm (blue), actin staining with phalloidin at 633 nm for structure (magenta). Insets are zoomed in regions of one cell from the outlined white box. G-CatchER⁺ expression has a Pearson's coefficient of 0.91 when compared with ER-Tracker red.

(B) 1 mM of 4-cmc was added to initiate a release of Ca²⁺ from the ER in C2C12 cells. n = 21 cells. F₀ is the fluorescence intensity at the initial time point of measurement and ΔF = F_t–F₀, where F_t is the fluorescence intensity at time t.

(C) 50 μM of CPA was added to initiate a release of Ca²⁺ from the ER in Cos-7 cells. n = 30 cells.

(D) 500 μM of ATP was added to initiate a release of Ca²⁺ from the ER in C2C12 cells. n = 9 cells.

(E) C2C12 cells plotted as normalized ΔF/F₀ in response to 1 mM 4-cmc showing overall release of whole cells is similar where each color circle matches each cell in inset.

(F) Pixel by pixel plot of ΔF/F₀ response from the six cells with R = 0.42.

(G) ΔF/F₀ intensity map of the six cells analyzed in E&F. Scale bars, 20 μm.

See also Figure S3.