[View Larger Version of this Image]

Figure S1. STIM1 accumulation precedes I_CRAC activation during IP₃-induced Ca²⁺ release. (A) A Jurkat cell expressing GFP-STIM1 imaged by TIRF microscopy during perforated-patch recording. TCR cross-linking with 10 µg/ml anti-CD3 mAb generates IP₃ and depletes stores, triggering STIM1 redistribution. Anti-CD3 was applied during the time shown in C. (B) CRAC currents elicited by voltage ramps from -122 to +50 mV during the image acquisitions shown in A. Data were corrected for the leak current recorded before stimulation and expressed relative to cell size (capacitance). (C) Time courses of I_CRAC development (measured at -122 mV) and GFP-STIM1 fluorescence (averaged across the entire cell footprint). (D) The data from C were normalized to the same minimum and maximum values to compare the time courses of I_CRAC and GFP-STIM1 fluorescence. The latency of I_CRAC activation relative to GFP-STIM1 accumulation is summarized in Fig. 1 E for four cells stimulated with anti-CD3. Bar, 2 µm.