Phosphatidylethanolamine (PE)

Phosphatidylethanolamines are a class of phospholipids found in biological membranes. They are synthesized by the addition of CDP-ethanolamine to diglycerides, releasing CMP. S-Adenosyl methionine can subsequently methylate the amine of phosphatidylethanolamines to yield phosphatidylcholines. It can mainly be found in the inner (cytoplasmic) leaflet of the lipid bilayer. Synthesis of PE through the phosphatidylserine decarboxylation pathway occurs rapidly in the inner mitochondrial membrane. However, phosphatidylserine is made in the endoplasmic reticulum. Because of this, the transport of phosphatidylserine from the endoplasmic reticulum to the mitrochondrial membrane and then to the inner mitochondrial membrane limits the rate of synthesis via this pathway. The mechanism for this transport is currently unknown, but may play a role in regulation of the rate of synthesis in this pathway.