STIM1 and acute lymphoblastic leukemia: Indeed, overexpression of STIM1-CFP in NALM6 cells abrogated the induction of p-ERK1/2 by pevonedistat and correlated with increased cleavage of PARP compared to wild-type controls, implicating changes in the Orai1:STIM1 ratio in pevonedistat-induced apoptosis of ALL cells (Figure 3C).