Lipid droplet functions beyond energy storage

Abstract

Lipid droplets are cytoplasmic organelles that store neutral lipids and are critically important for energy metabolism. Their function in energy storage is firmly established and increasingly well characterized. However, emerging evidence indicates that lipid droplets also play important and diverse roles in the cellular handling of lipids and proteins that may not be directly related to energy homeostasis. Lipid handling roles of droplets include the storage of hydrophobic vitamin and signaling precursors, and the management of endoplasmic reticulum and oxidative stress. Roles of lipid droplets in protein handling encompass functions in the maturation, storage, and turnover of cellular and viral polypeptides. Other potential roles of lipid droplets may be connected with their intracellular motility and, in some cases, their nuclear localization. This diversity highlights that lipid droplets are very adaptable organelles, performing different functions in different biological contexts.

Connecting pancreatic islet lipid metabolism with insulin secretion and the development of type 2 diabetes

“…140 ester and retinol ester) surrounded by a PL monolayer. 122 The lipid droplet surface is studded by the perilipin (PLIN) family of proteins (PLIN1-5) that play an important role in stabilization of LD, lipolysis, and interaction of LD with other proteins and organelles (Table 1). 123 LD provide temporal and spatial regulation of lipid metabolism and have diverse functions beyond lipid metabolism through interaction with a wide array of proteins and intracellular organelles, including the ER, mitochondria, the nucleus, and lysosomes.…”

“…123 LD provide temporal and spatial regulation of lipid metabolism and have diverse functions beyond lipid metabolism through interaction with a wide array of proteins and intracellular organelles, including the ER, mitochondria, the nucleus, and lysosomes. 122 The best characterized function of LD is to regulate mobilization of stored lipids through interaction with lipases and lysosomes (autophagy), as recently reviewed. 60,123 LD are coated with Rab proteins and are mobile within cells.…”

“…LD generate from the ER, where triglyceride synthesis occurs, and often maintain contact with the ER. 122 On the other hand, reduction of lipid droplet formation has been associated with lower ER stress in the liver of mice fed a high-fat diet, indicating that the contribution of LD to stress mitigation depends on the context of stress and cell types. 122 In hepatocytes treated with tunicamycin and cardiomyocytes treated with PA, the promotion of lipid droplet formation mitigates ER stress.…”

Lipid droplet autophagy during energy mobilization lipid homeostasis and protein quality control

“…They also store hydrophobic vitamins and lipid signaling molecules, and sequester toxic lipids. Finally, emerging evidence support a role for LDs in protein storage, assembly, and quality control (10, 11). …”

Buriti of the cerrado of Minas Gerais, Brazil: physical and chemical characterization and content of carotenoids and vitamins

“…However, this was less than 19.00 g.100 g -1 found by Darnet et al (2011) in fruits of the same species collected from different Brazilian states that have the Cerrado biome as predominant. The consumption of fruit sources of lipids is important, since these consist especially of fatty acids which play important roles in the structure of cell membranes and in metabolic processes, and act in the transport of fat soluble vitamins and to be hormone precursors (Welte & Gould, 2017).…”