Lipid Landscape of human cells

Eukaryotic cells synthesise thousands of lipid species, yet the principles that organise them across compartments remain unclear. Here we introduce PAP-SL, parallel (immuno)affinity purification coupled to shotgun lipidomics, to map [~]300 lipid species across six compartments of human cells and uncover general rules of lipid organisation. Correlation analyses of stoichiometric lipid compositions resolved archetypal distribution trajectories. Biosynthetic origin set the baseline: mitochondrial and lysosomal pathways generated confined pools, whereas the ER acted as a dispatch hub shaping downstream membrane territories. The ER established the saturated plasma membrane through transfer of phosphatidylserine, sphingolipids, and cholesterol, together with species-level selection of more saturated glycerophospholipids across diverse headgroups, while less-saturated species moved unselectively into mitochondria. The ER also channelled ether-linked glycerophospholipids to lysosomes, forming a territory dominated by ether phosphatidylcholine that collapsed under ethanolamine-driven metabolic rewiring. PAP-SL defines a framework to resolve lipid organisation and its metabolic plasticity in health and disease.