Figure 1. Orai1 role in Ca²⁺-entry.

(a) Example paired comparison of Ca²⁺-entry in EPCs transfected with Orai1 siRNA 1 (Or1.si.1) or scrambled (sc.si) siRNA (N=8 each). EPCs were store-depleted using 1 μmoles/L thapsigargin in Ca²⁺-free solution for 30 min prior to re-addition of extracellular Ca²⁺ (0.2 mmoles/L) to show Ca²⁺-entry. (b) As for (a) but a paired comparison of Ca²⁺-entry after transfection of HUVECs with dominant negative (DN) mutant (R91W) Orai1 or the DNA vector (vec.) only (N=8 each). (c) Summary data for experiments of the type shown in (a, b). Each test data set (black bars) was compared to its own control even though only one control bar (white) is shown (n/N=5/96, 4/48 and 4/72 for each paired experiment). Controls were sc. si. or vec. whereas tests were Or1.si.1 or DN Orai1. (d) Example HUVEC intracellular Ca²⁺ measurement in the presence of extracellular 1.5 mmoles/L Ca²⁺ showing responses to VEGF (100 ng/mL) after transfection with Or1.si.1 or sc.si (N=8). (e) Summary data for experiments of the type illustrated in (d) showing measurements for the transient and sustained effects of VEGF (n/N=3/24). (f) As for (d) but cells were pretreated with anti-TRPC1 antibody (Ab) or its peptide-preadsorbed control (+pep.) (N=16). (g) Mean data for independent experiments of the type shown in (f) (n/N=4/56).