Ninjurin-1 is a protein encoded by the NINJ1 gene in humans. This transmembrane protein plays a critical role in plasma membrane rupture during lytic cell death. NINJ1 is involved in the terminal stages of cell rupture across various cell death pathways, including pyroptosis, necroptosis, and ferroptosis. By disrupting cell membranes, NINJ1 facilitates the release of intracellular proteins, such as lactate dehydrogenase and various Damage Associated Molecular Patterns (DAMPs) into the extracellular environment, triggering inflammation. Upon activation, NINJ1 assembles into a chain-like oligomer that forms a ring structure—dubbed the "Ninja Cutter"—which, like a cookie cutter, cuts and releases membrane disks, enabling cell rupture.
