FIG. 1.

Stimulus-induced calcium mobilization in wild-type and mutant Jurkat cell lines. Jurkat subclones were loaded with indo-1 and stimulated with 1 μg of anti-CD3 antibody (OKT3) per ml or 0.1 mM pervanadate (PV). The ratio of the fluorescence emission of the Ca²⁺-bound to -free form of indo-1 is plotted as a function of time after addition of the stimulus. The cells tested in each panel are as follows: JURKAT, wild-type Jurkat cells; J.CaM1, Lck-negative Jurkat subclone; P116, ZAP-70-negative Jurkat subclone; P116.C39 and P116.C40, ZAP-70-transfected P116 subclones; DK33, P116 subclone transfected with a catalytically inactive ZAP-70 mutant.