Delipidation, LD induction, and cell fusion

Cells were delipidated by culturing in serum‐free medium supplemented with 5% lipoprotein‐deficient serum [LPDS; prepared as described in Goldstein et al (1983)] for 3 days. For experiments involving LD induction, unless otherwise stated, cells were supplemented with 0.2 mM OA [final concentration, OA supplemented in complex with BSA in 8:1 molar ratio prepared in serum‐free DMEM as described in Hölttä‐Vuori et al (2013)] for indicated times. For cell fusion, cells were first co‐plated for 2.5 h. Fusion was induced by adding PEG 1500 (50% w/v) to the cells for 1 min at RT, followed by four washes with PBS.