Fig. 4

LRRK2-GS induces ER Ca²⁺ depletion by maintaining SERCA–PLN interactions. a, b Representative time-lapse images of cytosolic Ca²⁺ dynamics in astrocytes isolated from non-Tg and LRRK2-GS mice. Astrocytes were treated with α-synuclein (α-Syn) for 24 h, after which cytosolic Ca²⁺ signals in response to histamine (500 μM) were visualized by fluorescence microscopy in cells loaded with Fluo4-AM. Fluorescence intensity is displayed in pseudo-colors (bottom: scale palette) (a). Representative Ca²⁺ transients were plotted (b; left) and the average amplitude and duration (b; right) of Ca²⁺ spark were quantified. c, d Representative images of ER Ca²⁺ dynamics in astrocytes expressing G-CEPIA1er. Astrocytes were treated with α-Syn, and then Ca²⁺ signals were visualized by fluorescence microscopy. Changes in fluorescence intensities are indicated by pseudo-colors (c). Plots of representative fluorescence dynamics (d; left), and the slope of a linear fit to G-CEPIA1er fluorescence changes during the interval T1 to T2 in left panel of D was obtained; the indicated differences are shown (d, right). e Astrocytes isolated from non-Tg and LRRK2-GS mice were treated with α-Syn and immunoprecipitated with an antibody against LRRK2 or SERCA, followed by immunoblot analysis with the indicated antibodies. Crosshatching denotes a cleaved caspase-12 band. All graphs represent means ± SD of three independent experiments (*p < 0.05)