THE MOLECULAR SELECTIVITY OF PHOSPHOLIPASE-D IN HL-60 GRANULOCYTES

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