The loss of cells that occurs during MI and HF is largely due to necrotic cell death, yet the molecular mechanisms underlying necrosis, specifically plasma membrane rupture, are not well defined. A genome-wide, shRNA loss-of-function screen identified components of SNARE-mediated membrane fusion as potential facilitators of Ca 2+ and ROS-induced membrane rupture. Here, we targeted Nsf (N-ethylmaleimide sensitive factor) due to its requirement in SNARE recycling, redox sensitivity, and lack of gene homologs. Deletion of Nsf from 3T3 fibroblasts, using CRISPR-Cas9n ( Nsf -/- ), inhibited membrane rupture and improved cell viability following Ca 2+ overload (ionomycin) and ROS (H 2 O 2 ) induced cell death. Further, stable overexpression of NSF augmented membrane rupture and decreased cell viability following necrotic insults. Next, using high-resolution live cell microscopy we examined membrane blebs - herniations of the plasma membrane that precede rupture and necrosis. Nsf -/- and WT cells were treated with ionomycin or H 2 O 2 and imaged for 4h with automated Z-stack images taken every 5m. Ionomycin and H 2 O 2 induced prominent blebs in nearly every WT cell followed by membrane rupture. Strikingly, loss of Nsf ablated bleb formation (Fig 1). Studies are ongoing in cardiac-specific Nsf -/- mice to define if this novel mechanism contributes to myocyte death during IR injury. Deletion of Nsf in adult cardiomyocytes does not result in a baseline phenotype, increasing the translational potential of NSF targeted therapy. In summary, our results identify a new molecular component required for membrane blebbing that occurs during pathogenic cell death.