The molecular selectivity of phospholipase D in HL60 granulocytes.

The molecular selectivity of PLD in PMA-stimulated HL60 granulocytes was determined by HPLC analysis of [3H]butanol incorporation into phosphatidyl[3H]butanol (Ptd[3H]But) molecular species. Comparison with phospholipid compositions confirmed that PLD acted primarily on phosphatidylcholine (PtdCho). Apparent enzyme selectivity was suggested by negligible formation of PB16:0/16:0 and preferential synthesis of Ptd[3H]But species containing sn-1 18:0. Culture with exogenous 18:2n-6 or 20:4n-6 readily modified both PtdCho and Ptd[3H]But compositions, and accentuated the apparent selectivity of stimulated PLD for sn-1 18:0 species of PtdCho. Such modifications to PLD-based signalling mechanisms may contribute to the modulatory effects of altered dietary lipid intakes on cellular functions.