Lipid particle organization

Lipid droplets (LDs) are cytosolic structures found in cells of all eukaryotes, comprising a monolayer of phospholipids surrounding a core of uncharged lipids such as triglyceride (TAG) and sterol esters. CIDEA, CIDEB and CIDEC were first studied for their roles in promotion of apoptosis but they are also known to play a role in energy metabolism. CIDEA and C bind to lipid droplets and regulate their enlargement, thereby restricting lipolysis and favouring storage (by promoting net neutral lipid transfer from smaller to larger lipid droplets). LD formation involves the partitioning of neutral lipids from their site of synthesis at the endoplasmic reticulum (ER) to the cytosol. The fat storage-inducing transmembrane proteins 1 and 2 (FITM1 and FITM2), associated with the ER membrane, mediate binding and partitioning of TAGs into LDs. The short-chain dehydrogenases/reductases (SDR) family is a large family of NAD- or NADP-dependent oxidoreductase enzymes. 17-beta-hydroxysteroid dehydrogenase 13 (HSD17B13) is a recently-discovered enzyme of unknown physiological function that is associated with lipid droplets and significantly upregulated in patients with nonalcoholic fatty liver disease. Hypoxia-inducible lipid droplet-associated protein (HILPDA) is a lipid droplet protein and stimulates intracellular lipid accumulation.

Summary from Reactome (R-HSA-8964572), read 2026-09-23.