Figure 5.
STIM1-CC2 fails to oligomerize in response to store depletion. (A) STIM1-CC2 was constructed by introducing a premature stop codon at aa 392 as shown. (B) Confocal images of the footprint of a HEK 293 cell cotransfected with CFP-STIM1-CC2 and mCherry-myc-Orai1, before and after treatment with 1 μM TG to deplete Ca2+ stores. Bar, 5 μm. (C) Time course of mean FRET-E (±SEM) from HEK 293 cells coexpressing CFP- and YFP-labeled STIM1-CC2 (red, n = 9); the FRET-E response of STIM1-WT (black, n = 8) and STIM1-CC1 (green, n = 7) are reproduced from Figure 2C for comparison. 1 μM ionomycin was added as indicated above the graph.