An expanding appreciation for the varied functions of neutral lipids in cellular organisms relies on a more detailed understanding of the mechanisms of lipid production and packaging into cytosolic lipid droplets (LDs). Conventional lipid profiling procedures involve the analysis of tissue extracts and consequently lack cellular or subcellular resolution. Here, we report an approach that combines the visualization of individual LDs, microphase extraction of lipid components from droplets, and the direct identification of lipid composition by nanospray mass spectrometry, even to the level of a single LD. The triacylglycerol (TAG) composition of LDs from several plant sources (mature cotton (Gossypium hirsutum) embryos, roots of cotton seedlings, and Arabidopsis thaliana seeds and leaves) were examined by direct organelle mass spectrometry and revealed the heterogeneity of LDs derived from different plant tissue sources. The analysis of individual LDs makes possible organellar resolution of molecular compositions and will facilitate new studies of LD biogenesis and functions, especially in combination with analysis of morphological and metabolic mutants. Furthermore, direct organelle mass spectrometry could be applied to the molecular analysis of other subcellular compartments and macromolecules. LDs4 are organelles that are specialized for the storage of neutral lipids and as such provide energy-rich reserves in all cellular organisms (1). Understanding LD ontogeny is of major importance to human physiology; on the one hand, seed oils, packaged in LDs, make up a growing proportion of daily caloric intake in most diets around the world, and on the other hand, the regulation of lipid storage and mobilization underlies significant human health issues: obesity, diabetes and cardiovascular disease.Although storage is considered the principal role of neutral lipids, LDs in nonfat storing tissues recently have become more appreciated for their dynamic nature and functional roles independent of storage. These roles include acyl reserves for phospholipid recycling (2), lipid signaling (3), membrane trafficking (2, 4), inflammation and cancer (5), and hostpathogen interactions (6, 7). These various functions attributed to LDs vary with cell type and likely are manifested by differences in droplet composition. The basic structural model of LDs in plant seeds provides a thermodynamically stable organization that is thought to be conserved throughout eukaryotes, although the nature of the lipids and proteins associated with droplets varies with cell/tissue type. The structure describes a neutral lipid core (triacylglycerols in plant seeds and/or steryl esters in other organisms or cell types) surrounded by a phospholipid monolayer with specific proteins associated with the LD surface (8). Although the endoplasmic reticulum is considered by most to be the major cellular location for LD biogenesis, droplets associate frequently with other subcellular compartments, presumably to carry out unique functions (9).The recent emphasis...
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.