Proteins involved in lipid metabolism (Dgat1)

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

Top: The addition of the third fatty acid to the amphiphilic diacylglycerol molecule is the step that produces storage fat (TAG) with only hydrophobic properties. This reaction is carried out by acyltransferases abbreviated DGAT. DGAT1 (blue dots) is an enzyme that permanently resides on the endoplasmic reticulum, whereas DGAT2 is exclusively found on lipid droplets.

Right: GFP-tagged DGAT1 (green) highlights the network of the ER and does not coincide with lipid droplets (red).

Function: Under normal conditions DGAT1 is the major enzyme producing TAG in Dictyostelium cells. It is also able to synthesize a substance called mono-alkyl-di-acyl-glycerol (MDG), that differs from TAG only in that one chain is connected by an ether-bond while the other two are ester-linked.

References:

• Du, X., Herrfurth, C., Gottlieb, T. Kawelke, S., Feussner, K., Rühling, H., Feussner, I., Maniak, M.: The essential function of Dictyostelium Dgat1 in triglyceride production, but not in ether lipid synthesis, can be substituted by Dgat2. Eukaryotic Cell, 13,  517-526, 2014