biostudies-literatureUnknown28(3)Lan ZHebei Provincial Natural Science FoundationNational Natural Science Foundation of ChinaMajor Research PlanP4-ATPases are phospholipid flippases responsible for the transbilayer lipid asymmetry. ATP8A1, a P4-ATPase family member, has been reported to be involved in phosphatidylserine (PS) translocation at the <i>trans-</i>Golgi network, early endosomes and recycling endosomes. However, the possible roles of the PS on late endosomes/lysosomes pathway and how they are regulated remain to be elucidated. This study showed enrichment of ATP8A1 in Rab7-positive late endosomal compartments, and that ATP8A1 primarily flips the endosomal PS from the luminal leaflet to the cytosolic leaflet but not the PS in the inner leaflet of the plasma membrane. ATP8A1 depletion accelerates the lysosome-destined cargo proteins transfer into the intraluminal vesicles (ILVs) of multivesicular bodies (MVBs) and alters tiScience111973https://www.ebi.ac.uk/biostudies/studies/S-EPMC11904568biostudies-literatureATP8A1-translocated endosomal phosphatidylserine fine-tunes the multivesicular body formation and the endo-lysosomal traffic.PMC11904568Li CTian YYi PWang YZhang RLan ZfalseATP8A1-translocated endosomal phosphatidylserine fine-tunes the multivesicular body formation and the endo-lysosomal traffic.P4-ATPases are phospholipid flippases responsible for the transbilayer lipid asymmetry. ATP8A1, a P4-ATPase family member, has been reported to be involved in phosphatidylserine (PS) translocation at the <i>trans-</i>Golgi network, early endosomes and recycling endosomes. However, the possible roles of the PS on late endosomes/lysosomes pathway and how they are regulated remain to be elucidated. This study showed enrichment of ATP8A1 in Rab7-positive late endosomal compartments, and that ATP8A1 primarily flips the endosomal PS from the luminal leaflet to the cytosolic leaflet but not the PS in the inner leaflet of the plasma membrane. ATP8A1 depletion accelerates the lysosome-destined cargo proteins transfer into the intraluminal vesicles (ILVs) of multivesicular bodies (MVBs) and alters t2025-01-01T00:00:00Z2025 Mar2026-07-15T11:10:34.174Z2025-04-04T00:06:59.493ZS-EPMC119045684008371810.1016/j.isci.2025.111973