Figure 3.

Abnormal calcium concentration in cellular compartments of N2a cells overexpressing wild type and mutanthPS1. N2a stably transfected cells overexpressing hPS1WT, hPS1E280A and hPS1Δ9 were used to measure intracellular calcium (Ca²⁺) concentrations in basal conditions using transient transfection of a compartment-specific aequorin constructs. Ca²⁺ intracellular levels were perturbed with the addition of 100 µM bradykinin for cytosolic and mitochondrial light recordings; for ER Ca²⁺ measurements, cells were first depleted of extracellular Ca²⁺ with EGTA, then intracellular Ca²⁺ concentrations were perturbed with the addition of 1 mM CaCl2. Finally, 100 µM bradykinin was added to deplete Ca²⁺ stores. (a) Representative averaged recordings of cytosolic calcium in the different cell lines, showing the maximum calcium concentration reached after Bradykinin addition. (b) Bar graphs of the maximum cytosolic calcium showing increased calcium concentration in hPS1WT and hPS1E280A cells. (c) Representative averaged recordings of ER calcium in N2a mock and hPS1 overexpressing cells. (d) Bar Graphs of maximal calcium concentration detected in the Endoplasmic Reticulum, hPS1WT showed increased calcium levels in the ER. (e) Representative averaged recordings of maximal mitochondrial calcium concentration in the different cell lines. (f) Bar graphs of the maximal mitochondrial calcium concentration after Bradykinin addition; mean and ±SEM are presented for all experiments, Two Way ANOVA, *p < 0.05, **p < 0.01, ***p < 0.001,****p < 0.0001 n = 3.