Fig.2.

Cytoplasmic lipid droplet and serum lipoprotein structures. A commonality to cytoplasmic and serum lipid carriers that reflects their shared origin is the membrane of the endoplasmic reticulum. Both particles bud from the ER membranes as neutral lipid is synthesized and approaches insolubility in the membrane. Insolubility is overcome by micellar association with phospholipids and, to a lesser extent, sterols, from the ER and proteins, such as apoB (shown), acyltransferases, lipases, or perilipins (generically indicated by crescents).