SAMD8 is an endoplasmic reticulum (ER)-resident phospholipase with dual enzymatic functions in sphingolipid metabolism. Primarily, SAMD8 acts as a ceramide phosphoethanolamine (CPE) synthase, transferring the phosphoethanolamine headgroup from phosphatidylethanolamine to ceramide to produce CPE 12. This CPE synthase activity is catalytically dependent and structurally determined by specific residues in the exoplasmic loops adjacent to the catalytic site 1. Critically, SAMD8 functions as a ceramide sensor that regulates ceramide homeostasis in the ER, preventing aberrant ceramide accumulation and mislocalization to mitochondria 3. This regulation requires both enzymatic activity and the N-terminal sterile alpha motif (SAM) domain, which enables protein-protein interactions 3. During apoptosis, SAMD8 is proteolytically cleaved by caspase-6, releasing ceramide-mediated suppression and permitting cell death 4. Recent evidence indicates SAMD8 expression is upregulated during ex vivo lung perfusion and correlates with immune modulation, particularly NK cell populations 5, and has been identified as a prognostic factor in glioma 6. These findings establish SAMD8 as a critical regulator of ER ceramide homeostasis with implications in apoptosis regulation and potentially in tissue preservation and cancer biology.