18:0,18:1 PS

18:0,18:1 PS is a predominant phosphatidylserine subtype found in cells, exosomes, and HIV particles, as well as being abundant in the brain. It plays a crucial role in maintaining membrane structure, lipid raft organization, and intracellular transport. This compound interacts with very long-chain sphingolipids in a cholesterol-dependent manner to mediate coupling between membrane leaflets and can induce the aggregation of glycosylphosphatidylinositol-anchored proteins. Furthermore, clusters formed by 18:0,18:1 PS and cholesterol not only support the proper distribution of cholesterol in the bilayer membrane but also protect it from oxidative damage effectively.

18:0,18:1 PS is a predominant phosphatidylserine subtype found in cells, exosomes, and HIV particles. It accounts for approximately 22-60% of total PS in various cell lines, such as PC-3, HEp-2, PSA3 CHO, HeLa, MT4, A549, and mouse fibroblasts. In PC-3 cell-derived exosomes, it makes up about 40% of the total PS, theoretically covering around 80% of the inner leaflet surface of exosomes overlapped by outer leaflet sphingolipids. For HIV-1 particles, it potentially covers about 60% of the inner leaflet in a similar manner. The cross-insertion effect of PS 18:0,18:1 with SM d18:1/24:0 is stronger than that of PS 16:0/18:1, and it is the only PS type tested that shows enhanced cross-insertion with SM d18:1/24:0 in the presence of cholesterol. In Giant Unilamellar Vesicles (GUVs), it facilitates phase separation with cholesterol and protects cholesterol more efficiently from cholesterol oxidase than PS 16:0/18:1, PS 18:1/18:1, or PS 16:0/18:2. Furthermore, PS 18:0,18:1 promotes the clustering of endogenous GPI-APs on PSA3 CHO cell surfaces as effectively as PS 18:0/18:0 and more effectively than PS 18:1/18:1 or PS 12:0/12:0.

In rat brains, the abundance of 18:0,18:1 PS is significantly higher compared to phosphatidylserine in the heart, kidneys, and liver, comprising 26% of the total phosphatidylserine content in the brain.