Figure 1.

Eeyarestatin 1 (ES1) Interferes with the Cell Ca²⁺ Homeostasis by Enhancing the Ca²⁺ Leakage from ER in a Dose- and Time-Dependent Manner

(A and B) Increasing concentrations of ES1 produced accumulation of Ca²⁺ in cytosol (A), which resulted from the loss of ER (B) Ca²⁺ due to the dose-dependent gain of Ca²⁺ leakage.

(C and D) The TG responses in cytosolic Ca²⁺ (C) after short exposures to ES1 reflected the dose-dependent decrease of ER Ca²⁺ (D) and the gain of Ca²⁺ leakage.

(E) Surges in [Ca²⁺]_cyt after TG application were integrated between 1,200 and 1,800 s to obtain the area under the curve (post-TG AUC) for the experiments shown in (A).

(F) Decreases of [Ca²⁺]_ER induced by ES1 in experiments shown in (B) were quantified just before TG application (pre-TG [Ca²⁺]_ER).

(G) The Ca²⁺ leakage from ER was estimated by measuring the half-time of the decay in [Ca²⁺]_ER (post-TG t_1/2) induced by TG in experiments shown in (B).

(H and I) The relative amplitude of [Ca²⁺]_cyt increases after TG applications (post-TG Δ[Ca²⁺]_cyt) (H) and [Ca²⁺]_ER levels just before TG application (pre-TG [Ca²⁺]_ER) (I) are shown for the experiments in (C and D).

DMSO controls are denoted as mock. Application time points are indicated by vertical lines in (A–D) (mock/ES1; 1μM TG). Data are presented as means ± SEM. n.a., not analyzed; n.s., not significant; ***p < 0.001. N = 30–47 cells per experimental setting. See also Figure S1.