Choline phospholipids: signal transduction and carcinogenesis.

Phospholipids act as vital elements in transmembrane signaling. Agonist-induced hydrolysis of phosphatidylinositides has been established as a major mechanism for transmitting messages into the interior of cells via protein phosphorylation cascades, ultimately regulating gene transcription. There is a growing body of evidence that choline phospholipids (phosphatidylcholine, sphingomyelin, and their metabolites) also are important mediators and modulators of transmembrane signaling. These functions may explain how choline phospholipids influence normal physiological processes as well as a diverse group of pathological processes.