STIM1 and acute lymphoblastic leukemia: In support of this mechanistic role for STIM1 in Ca2+ regulation in pevonedistat-treated ALL cells, we showed that in NALM6 cells overexpressing Orai1-YFP, the fluorescent signal was distributed evenly in the plasma membrane with undetectable intracellular localization, whereas in the pevonedistat-treated NALM6-Orai1-YFP expressing cells the signal was clustered in the plasma membrane with minimal intracellular localization.