glycerophosphoethanolamine

Glycerophospholipids are a major class of lipids that form the structural basis of cellular membranes in all domains of life. They consist of a glycerol backbone esterified at the first two positions with fatty acids and linked at the third position to a phosphate group that bears a polar head group. The combination of hydrophobic fatty acyl chains and a hydrophilic head group gives amphipathic molecules essential for membrane bilayer formation and curvature.

The most common head groups in eukaryotes are choline (phosphatidylcholine), ethanolamine (phosphatidylethanolamine), serine (phosphatidylserine), and inositol (phosphatidylinositol). Other variants include phosphatidylglycerol and cardiolipin, the latter being abundant in mitochondrial membranes. Phosphatidylinositol and its phosphorylated derivatives participate in signaling pathways, including phosphoinositide signaling.

Biosynthesis occurs via the glycerol-3-phosphate pathway. Glycerol-3-phosphate is acylated to form lysophosphatidic acid and then phosphatidic acid, which serves as an intermediate. The head group is attached through CDP-activated intermediates: phosphatidylcholine via CDP-choline, phosphatidylethanolamine via CDP-ethanolamine, phosphatidylserine via serine exchange, and phosphatidylinositol via inositol transfer. Remodeling and de novo synthesis produce the diverse glycerophospholipid species observed in cells.

Hydrolysis by phospholipases A, C, or D releases fatty acids, diacylglycerol, or head group-derived products, integrating glycerophospholipids into membrane remodeling and signaling processes. Abnormal glycerophospholipid metabolism has been linked to metabolic, cardiovascular, and neurodegenerative diseases.