RT Journal Article SR Electronic T1 Lipid-associated PML structures assemble nuclear lipid droplets containing CCTα and Lipin1 JF Life Science Alliance JO Life Sci. Alliance FD Life Science Alliance LLC SP e202000751 DO 10.26508/lsa.202000751 VO 3 IS 8 A1 Jonghwa Lee A1 Jayme Salsman A1 Jason Foster A1 Graham Dellaire A1 Neale D Ridgway YR 2020 UL https://www.life-science-alliance.org/content/3/8/e202000751.abstract AB Nuclear lipid droplets (nLDs) form on the inner nuclear membrane by a mechanism involving promyelocytic leukemia (PML), the protein scaffold of PML nuclear bodies. We report that PML structures on nLDs in oleate-treated U2OS cells, referred to as lipid-associated PML structures (LAPS), differ from canonical PML nuclear bodies by the relative absence of SUMO1, SP100, and DAXX. These nLDs were also enriched in CTP:phosphocholine cytidylyltransferase α (CCTα), the phosphatidic acid phosphatase Lipin1, and DAG. Translocation of CCTα onto nLDs was mediated by its α-helical M-domain but was not correlated with its activator DAG. High-resolution imaging revealed that CCTα and LAPS occupied distinct polarized regions on nLDs. PML knockout U2OS (PML KO) cells lacking LAPS had a 40–50% reduction in nLDs with associated CCTα, and residual nLDs were almost devoid of Lipin1 and DAG. As a result, phosphatidylcholine and triacylglycerol synthesis was inhibited in PML KO cells. We conclude that in response to excess exogenous fatty acids, LAPS are required to assemble nLDs that are competent to recruit CCTα and Lipin1.