Alkylacylglycerophospholipids

Alkylacylglycerophospholipids, often abbreviated as AAGLs, are a class of phospholipids characterized by an ether linkage at the sn-1 position of the glycerol backbone. This ether linkage replaces the more common ester linkage found in diacylglycerophospholipids. In AAGLs, an alkyl group, which is a long-chain saturated or unsaturated hydrocarbon, is attached to the glycerol via an oxygen atom. The sn-2 position of the glycerol typically bears a fatty acid esterified to the hydroxyl group, and the sn-3 position carries a phosphate group linked to a polar head group, such as choline, ethanolamine, serine, or inositol.

These lipids are found in biological membranes of various organisms, including mammals, bacteria, and protozoa, although their abundance varies significantly. In mammals, they are particularly enriched in certain cell types, such as polymorphonuclear leukocytes (neutrophils), where they play roles in cellular signaling and inflammatory responses. The ether linkage confers greater stability to AAGLs compared to their esterified counterparts, making them more resistant to hydrolysis by phospholipases. This stability may be advantageous in environments where lipid breakdown is a concern. Research continues to explore the diverse physiological functions and metabolic pathways of alkylacylglycerophospholipids.