Ptdss1, encoding phosphatidylserine synthase 1, is an enzyme that catalyzes the conversion of phosphatidylcholine to phosphatidylserine, playing a crucial role in glycerophospholipid metabolism [1,3,6]. Phosphatidylserine is a vital component of cell membranes, and this metabolic pathway is significant for normal cellular functions [1,5].

In murine mammary tumors, depletion of Ptdss1 from tumor cells led to reduced ether-phosphatidylserine (ePS) levels, stunted tumor growth, and decreased tumor-associated macrophage (TAM) abundance. Ptdss1-deficient tumor cells exposed less phosphatidylserine during apoptosis, which was recognized by the PS receptor MERTK. Macrophage-specific Mertk-/-mice also showed suppressed tumor growth and reduced TAM infiltration. Additionally, in B cell lymphoma, inhibition of Ptdss1 caused an imbalance in the membrane phospholipidome, leading to BCR hyperactivation, aberrant Ca2+ signaling, and apoptotic cell death. In a mouse xenograft model, Ptdss1 inhibition suppressed tumor growth [2,4].

In conclusion, Ptdss1 is essential for maintaining proper phosphatidylserine levels in cells, which is crucial for normal cell function. Through gene-knockout or inhibitor-based studies in mouse models, it has been shown to play a significant role in tumor-promoting inflammation and the survival of B cell lymphoma cells, indicating its potential as a therapeutic target in cancer [2,4].