Abstract
Lipid droplets (LDs) are ubiquitous, dynamic organelles and function as a storage depot for neutral lipids, including triglycerides and cholesterol esters (Walther and Farese, 2012). The movement of lipid species into and out of LDs impacts a variety of cellular processes, such as energy homeostasis, lipid-based signaling, and membrane homeostasis (Greenberg et al., 2011). For example, neutral lipid storage is enhanced upon increased synthesis or uptake of lipid species. On the other hand, extracellular signals can enhance the release of lipid species packaged within neutral LDs. Thus, the investigation of topics involving lipid metabolism may require the assessment of cellular neutral lipid content. In this protocol, we describe the use of the fluorescent neutral lipid dye 4,4-difluoro-1,3,5,7,8-pentamethyl-4-bora-3a,4a-diaza-s-indacene (BODIPY 493/503) to facilitate quantification of neutral lipid content by flow cytometry and observation of LDs by microscopy.