Figure 2. Hyperactivation of calcineurin and dephosphorylation of Drp1 in HD cells.

• A. Phosphorylated and unphosphorylated proteins were separated from total cell lysates (2.5 mg) from cells of the indicated genotype. Equal amounts (20 µg) of total, phosphorylated and un-phosphorylated proteins were separated by SDS–PAGE and immunoblotted.
• B. Calcineurin enzyme activity measured in total cell extracts from cell lines of the indicated genotype. Data are mean ± SE of three independent experiments.
• C,D. Equal amounts of proteins (40 µg) from total cell lysates from cells of the indicated genotype were separated by SDS–PAGE and immunoblotted with the indicated antibodies. RCAN1L/actin levels (relative to their relative wt): 0.98 ± 0.05 in Q111/0; 0.82 ± 0.08 in Q111/1; 1.28 ± 0.21 in 48Q; 0.91 ± 0.04 in 70Q and 1.22 ± 0.02 in 45 + 47Q lymphoblasts.
• E. Representative traces of Fura-2 ratio of cytosolic Ca²⁺ ([Ca²⁺]_i) following passive discharge of ER Ca²⁺ stores by CPA (100 µM) in cells of the indicated genotype.
• F. Quantification of peak and basal [Ca²⁺]_i. Experiments were as in (E). Data represent mean ± SE of eight independent experiments (p < 0.002 by paired Student's t-test).