Summary scheme and brief description of stimulation methods used for adipose conversion and for the generation of different, distinct types of lipid droplets.

Major treatments and involved PLIN proteins are shown. Preadipocytes containing many small LDs are not differentiated for several weeks with AIM containing media as conventionally described (top row; cp. Fig. S1), but only very briefly (1–3 days), giving rise to “Adipocytes” (boxed area). Additional, short OA-treatment leads to “OA-Adipocytes” (boxed area, right side). Treatment with OA only - without AIM stimulation - leads to “OA-Preadipocytes” (bottom). Note the huge heterogeneity of sizes and colors of LDs seen within “OA-Adipocytes”. LDs are endogenously generated at the endoplasmic reticulum and stained positively for perilipin (“Endogenous-LDs”, red). Other LDs are obtained from the exogenous uptake of OA and stained positively for adipophilin, TIP47 and S3-12 (“Exogenous-LDs”, green). Merged LDs by fusion and mixed-type expression are seen by yellow color. The backway arrows indicate possible routes of LDs during lipolysis.