The CDP-choline pathway, first identified by Eugene Kennedy in 1956, is the predominant mechanism by which mammalian cells synthesize phosphatidylcholine (PC) for incorporation into membranes or lipid-derived signalling molecules. The CDP-choline pathway on the left-hand side represents one half of what is known as the Kennedy pathway. The other half on the right-hand side is the CDP-ethanolamine pathway which is responsible for the biosynthesis of the phospholipid product phosphatidylethanolamine (PE).
Source: [https://en.wikipedia.org/wiki/CDP-choline_pathway Wikipedia]