Figure 4.

Agonist activation of the B cell receptor induces Ba²⁺ entry in hTrp3-transfected wild-type but not IP₃R-KO DT40 cells. Ba²⁺ influx was measured in Fura-2-loaded, hTrp3-transfected wild-type or hTrp3-transfected IP₃R-KO cells as described in Fig. 1 legend. The cells were maintained in a nominally Ca²⁺-free medium, exposed to 2 μg/ml anti-IgM, and then Ba²⁺ (10 mM) was added where indicated. Shown are average curves ± SEM (in gray) from experiments performed on six single cells. The data are representative of three independent experiments (nine cells).