Figure 4: Targeting model of oleosin, caleosin, and steroleosin to a maturing oil body. Oleosin and caleosin are proposed to target directly a maturing oil body. In contrast, steroleosin is assumed to be integrated into the phospholipid bilayer of endoplasmic reticulum (ER) membrane prior to its lateral migration to a maturing oil body (adopted and modified from Figure 7 of Chen and Tzen, [78]).