Fig. 4
From: Transcriptomic profiling of milk fat globules in cows with different β-casein genotypes
Milk fat globule (MFG) formation in mammary epithelial cells (MEC). During MFG formation, triacylglycerol (TAG) cores are surrounded by a phospholipid monolayer derived from the endoplasmic reticulum, giving rise to lipid droplets (LDs). These LDs are then enveloped by an outer bilayer membrane originating from the apical plasma membrane of MEC, forming the milk fat globules (MFG). The resulting MFGs are enclosed by a trilayered milk fat globule membrane (MFGM), which includes both the phospholipid monolayer from the ER and the bilayer from the plasma membrane of MEC. MFG may enclose variable amounts of MEC cytoplasm between the monolayer and bilayer membranes, forming cytoplasmic crescents, which may also contain RNA in varying amounts.
