LACTB is a mitochondrial serine protease that functions as a multifaceted regulator of cellular metabolism and apoptosis. As a mitochondrial intermembrane space protein, LACTB assembles into ordered filaments that enhance its catalytic activity 1. Primary functions include regulating mitochondrial lipid metabolism by decreasing PISD protein levels and affecting phosphatidylserine conversion 2, and cleaving phospholipase A2 group VI (PLA2G6) to modulate oxidized phospholipid metabolism 3. Mechanistically, LACTB influences cancer progression through multiple pathways: it promotes ferroptosis by blocking HSPA8 transcription and inhibiting GSH/GPX4 signaling 4, triggers apoptosis through inner mitochondrial membrane remodeling and cardiolipin-enriched membrane binding 5, and suppresses migration via RHOC/Cofilin pathway downregulation 6. Post-translational modification by OXCT1-mediated succinylation at K284 inhibits LACTB proteolytic activity, promoting hepatocellular carcinoma progression 7. Clinically, LACTB exhibits cancer-type-specific roles: it acts as a tumor suppressor in breast, lung, colorectal, and glioblastoma cancers through proliferation inhibition, but gains oncogenic function in osteosarcoma through M5L/R469K mutations that dysregulate p53 8. LACTB also protects against cardiovascular-kidney-metabolic syndrome through kidney-specific mechanisms 3, and serves as a lenvatinib target in liver cancer therapy 4.