Proteins involved in lipid metabolism (Smt1, Ldp, Net4)

• Overview (pg.1) (pg.2)
• FcsA
• Plin (pg.1)(pg.2)
• Smt1, Ldp, Net4
• Dgat1
• Dgat2
• FcsB (pg.1)(pg.2)

Top: Surprisingly many proteins normally reside on the endoplasmic reticulum and are translocated to lipid droplets only after their formation. We have established this behaviour for Smt1, Ldp, and Net4, shown as purple dots. Thus, perilipin is rather an exception, being made in the cytoplasm.

Right: GFP-tagged proteins Smt1, Ldp, and Net4 (green) are present in a reticular pattern (ER) that extends throughout the cell in the absence of fatty acid (-FA). If fatty acid is added to the medium (+FA) the green proteins associate with small round organelles, the lipid droplets.

Function: Here, the model character of Dictyostelium can be recognized: The human homologue of Net4 was only known as a component of the nuclear envelope. We now could prove that it also surrounds lipid droplets in mammalian cells.

Reference:

• Du, X., Barisch, C., Paschke, P., Herrfurth, C., Bertinetti, O., Pawolleck, N., Otto, H., Rühling, H., Feussner, I., Herberg, F.W., Maniak, M.: Dictyostelium lipid droplets host novel proteins. Eukaryotic Cell 12, 1517-1529, 2013