eIF3e silencing disrupts intracellular Ca²⁺ homeostasis.

<p>A) Images of intracellular Ca²⁺ measured by the low affinity calcium dye, Fluo-5F upon 70 mM K⁺ stimulation in control and eIF3e KD cells. B) Fluo-5F fluorescence signal ratio (Ratio) and its time integral (A.U.C.) were calculated to assess the Ca²⁺ influx. Note that after 180-s stimulation the integrated Ca²⁺ load in eIF3e KD cells exceeds that of the negative control-treated cells. The arrow indicates the onset of stimulation. C) Comparison of Ca²⁺ load, expressed as the Area Under the Curve (A.U.C) 0-200 s after stimulation, between eIF3e KD and control cells (n = 27 cells, ***, P<0.001; Student’s t-test). D) As in (a), but experiments performed in the presence of vehicle (DMSO), the L-type calcium channel inhibitor isradipine (5 µM), the R-type calcium channel inhibitor SNX482 (0.2 µM) or the N-type calcium channel inhibitor ω-conotoxin GVIA (50 nM). Note that isradipine counteracts the effects of eIF3e KD on the sustained rise in cytosolic [Ca²⁺]. E) Quantitative analysis of Ca²⁺ load as in C for the conditions in D; (n = 18 cells for each condition, **, P<0.01; ***, P<0.001; Student’s t-test). F) Current-voltage (I-V) relations for whole-cell Ca²⁺ currents after 30 min incubation in 5 or 20 mM glucose (left); same experiment but in the presence of 5 µM isradipine (middle); or a non-L-type blocker cocktail (0.1 µM ω-agatoxin, 0.2 µM SNX-482 and 50 nM ω-conotoxin GVIA; right). n = 11 or more for each condition. * P<0.05, ** P<0.01, *** P<0.001 (Student’s t-test).