Platelet function WT and KI-STIM1^I115F (A-B) P-selectin (A) and integrin αIIbβ3 exposure after 10-minute stimulation with the indicated stimuli. (C) platelet spreading to collagen in static conditions, indicated as are of adherent cells (left), and number of adhered platelets (right); BSA was used as negative control in place of collagen. (D) Thrombus formation under flow, indicated as percentage of platelet covered area; Mann-Whitney U test (n = 6 per group) P value: ^^^≤0.0002, ^^≤0.0039 WT vehicle vs KI-STIM1^I115F vehicle; *****<0.00001 WT vehicle vs WT CIC-39Na and ##≤0.0036 KI-STIM1^I115F vehicle vs KI-STIM1^I115F CIC-39Na. Supplemental Figure 4A-B depicts fluorescent microscope images of the results; (E) % of aggregated platelets in the indicated conditions. To reach similar aggregations, WT platelets were diluted 1:3. Supplemental Figure 4C depicts slopes.