Phosphatidylserine exposed on apoptotic cell membrane (PS)

Phosphatidylserine is a negatively charged phospholipid normally restricted to the inner leaflet of the plasma membrane in healthy cells[1][2][4]. During apoptosis, specific enzymes (scramblases such as Xkr8 and TMEM16F, and inactivation of flippases like ATP11A/ATP11C) cause PS to be translocated to the outer leaflet[3][4][5]. This surface-exposed phosphatidylserine acts as a crucial "eat me" signal, recognized by receptors on phagocytes, prompting the removal of dying cells[3][5][6]. PS exposure also provides a pro-coagulant surface for blood clotting factors on activated platelets[4], and is involved in immune system modulation and viral entry through apoptotic mimicry[1][2]. Therapeutically, exposed PS serves as a target for antibody therapies, imaging agents, and modulation of macrophage and dendritic cell function in cancer, inflammation, and viral infection[6]. Detection of exposed PS is a gold-standard marker for identifying apoptotic cells (e.g., through Annexin V staining)[6].

Other names

Phosphatidylserine (PS)Ptd-L-SerPtdSerExposed phosphatidylserineOuter-leaflet phosphatidylserine

Antibody-dependent cellular cytotoxicity following antibody binding to exposed PS. Blocking immunosuppressive signaling induced by PS exposure. Labeling for targeted imaging/therapeutics.