(E) Pacs1+/+ and Pacs1-/- NIH-3T3 cells (C1 and C2 from (A)) were transfected with ER-GCamP6-210. ER Ca2+ was measured before and after treatment with 10 µM ATP. Kinetic traces show the mean 488/405 nm excitation ratio of each cell line with error bars indicating SEM. N=30 cells (3T3), 16 cells (C1), 25 cells (C2). Data are representative of 2 independent experiments. 