Fig. 3.

GPVI-induced Ca²⁺ signaling and store-operated Ca²⁺ entry is reduced in Tspan18-knockout platelets. Washed platelets from Tspan18^+/+ and Tspan18^−/− mice were loaded with the Ca²⁺ sensitive dye Fura-2 AM and Ca²⁺ measurements taken using a luminescence spectrophotometer. Collated data were fitted to an exponential one-phase association equation, shown in the left-hand panels, and maximal Ca²⁺ concentration was calculated, shown in the right-hand column. Platelets were stimulated with a 1 μg/ml collagen-related peptide (CRP), b 3 μg/ml collagen, and c 0.06 units/ml thrombin. d Platelets were treated in the absence of extracellular Ca²⁺ with thapsigargin (TG) to induce emptying of the intracellular Ca²⁺ stores. e The experiment in panel (d) was extended by the addition of 1.5 mM Ca²⁺ to the extracellular buffer. The rate constants were compared using an f test (*** denotes P < 0.001). Maximal Ca²⁺ concentrations were analysed by t test (* denotes P < 0.05; ns denotes not significant). Error bars represent the standard error of the mean from 2–6 independent experiments. Detailed methods are available online (https://etheses.bham.ac.uk/id/eprint/5903/)