Phospholipid analogues: side chain- and polar head group-dependent effects on phosphatidylcholine biosynthesis.

Abstract

In recent studies we showed that the phospholipid analogue hexadecylphosphocholine inhibits phosphatidylcholine biosynthesis by affecting the translocation of the rate-limiting enzyme of phosphatidylcholine biosynthesis, CTP:phosphocholine cytidylyltransferase (EC 2.7.7.15), to membranes, where it is active (Geilen et al. 1992. J. Biol. Chem. 267: 6719-6724). The present study was performed to investigate the structure-dependency of this effect. It is shown that the inhibitory properties of phospholipid analogues are dependent on their alkyl side chain length (dodecylphosphocholine eicosadecylphosphocholine). Furthermore, it is demonstrated that this inhibition of phosphatidylcholine biosynthesis by phospholipid analogues is also dependent on the polar head group (hexadecylphosphocholine > hexadecylphosphoethanolamine = hexadecylphosphoserine). These effects result from an inhibition of the CTP:phosphocholine cytidylyltransferase and are not due to an inhibition of choline uptake or differences in the cellular uptake of the phospholipid analogues investigated.