Figure 5.

De novo missense variants in ATP2B1 affect Ca²⁺ transport

(A) Fluorometric [Ca²⁺]_i analysis (for details, see supplemental methods) in untransfected (untransf.) HEK293 cells and cells expressing wild-type or mutated ATP2B1. Data are shown as mean [Ca²⁺]_i from five independent experiments after loading of the [Ca²⁺]_i indicator dye fura-2/AM and the final addition of EGTA (for a representative complete sequence of the experiment, see Figure S2).

(B) In order to investigate the Ca²⁺ transport of transfected HEK293, time-dependent [Ca²⁺]_i decline was analyzed after final addition of EGTA that is represented by the time constant tau. Data presented as mean and standard deviation from five independent experiments. As negative control served the likely non-pathogenic variant (3 times in gnomAD) p.Gly779Ser. The dashed line indicates the median tau value of ATP2B1 wild type. Data are shown as mean ± standard deviation represented by error bars. The results of a one-way ANOVA with the Games-Howell post-hoc test (each compared to wild type) is indicated as: ^∗∗p < 0.005; ^∗p < 0.05; ns: p > 0.05.