CERS1 (ceramide synthase 1) is a key enzyme in sphingolipid biosynthesis that catalyzes the synthesis of C18:0 ceramides from stearoyl-CoA and sphingoid bases 1. The enzyme plays critical roles in cellular stress responses and mitochondrial quality control by mediating mitophagy through C18 ceramide generation, which anchors autophagolysosomes to damaged mitochondria for elimination 23. CERS1 activity is regulated by the heat shock protein Hsp27, which acts as an endogenous inhibitor through direct protein-protein interaction 2. In pathological contexts, CERS1 demonstrates tumor suppressive properties, as ceramide analog treatments induce CERS1-mediated mitophagy and metabolic stress in cancer cells, leading to fumarate depletion and cell death 3. CERS1 expression correlates with disease severity in atopic dermatitis and positively associates with Staphylococcus aureus abundance, suggesting a role in skin barrier dysfunction 4. Age-related decline in CERS1 contributes to muscle wasting and dysfunction, with genetic variants reducing CERS1 expression associated with decreased grip strength in humans 5. These findings establish CERS1 as a critical regulator of cellular metabolism, stress responses, and tissue homeostasis through its specific ceramide synthetic activity.