FIGURE 5.

CHOP and Herp modulates ER Ca²⁺ homeostasis in MPP⁺-treated cells. Knockdown of CHOP (A) and Herp (B) alters ER Ca²⁺ store contents in MPP⁺-treated PC12 cells. Twenty-four hours after co-transfection with 2 μg of pBudCE4.1-YC4-ER with the indicated siRNA duplexes (100 nm), cultures were incubated with 0.5 mm MPP⁺ or vehicle control (Con). Changes in ER Ca²⁺ concentration ([Ca²⁺]_ER) were recorded at the indicated time points as described under “Experimental Procedures” and presented as the ratios of the YC4-ER fluorescence signal in MPP⁺-treated relative to untreated cultures. The values are the means and S.D. of measurements made in three separate cultures (n = 4 dishes, 4–6 microscopic fields/dish, 25–30 cells/field). *, p < 0.01; #, p < 0.05 (ANOVA with Scheffe post-hoc tests) compared with cultures treated with siRNA-Con.