Phorbol ester up-regulates capacities for nuclear translocation and phosphorylation of 5-lipoxygenase in Mono Mac 6 cells and human polymorphonuclear leukocytes

Blood. 2001 Apr 15;97(8):2487-95. doi: 10.1182/blood.v97.8.2487.


The leukotrienes are inflammatory mediators derived from arachidonic acid. It was demonstrated that the priming of leukocytes with phorbol-12-myristate-13-acetate (PMA) leads to the increased formation of 5-lipoxygenase (5-LO) products in parallel with the increased association of 5-LO with the nucleus and the activation of kinases that can phosphorylate 5-LO in vitro. Stimulation of the monocytic cell line Mono Mac 6 with calcium ionophore gave low 5-LO product formation and no detectable redistribution of 5-LO. However, after priming of Mono Mac 6 cells with phorbol esters, ionophore led to the association of 45% to 75% of cellular 5-LO with the nuclear membrane, to 5-LO kinase activation, to enhanced release of arachidonate, and to substantial leukotriene synthesis. Similar results were obtained for human polymorphonuclear leukocytes stimulated with low-dose ionophore. In addition, for each cell type, PMA priming up-regulated leukotriene biosynthesis in the presence of exogenous arachidonic acid. A protein kinase inhibitor, calphostin C, reduced the association of 5-LO with the nucleus and 5-LO kinase activity, and the formation of 5-LO products was inhibited. These results suggest that PMA up-regulates leukotriene biosynthesis not only by increasing the release of endogenous arachidonate, but also by increasing the capacity for 5-LO phosphorylation and for the translocation of 5-LO to the nucleus in leukocytes.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Active Transport, Cell Nucleus / drug effects*
  • Arachidonate 5-Lipoxygenase / metabolism*
  • Arachidonic Acid / metabolism
  • Calcimycin / pharmacology
  • Calcium / pharmacology
  • Calcium Signaling / drug effects
  • Cell Line
  • Cell Nucleus / metabolism
  • Enzyme Inhibitors / pharmacology
  • Humans
  • Ionophores / pharmacology
  • Leukotrienes / biosynthesis
  • Membrane Lipids / metabolism
  • Monocytes / drug effects*
  • Monocytes / metabolism
  • Naphthalenes / pharmacology
  • Neutrophils / drug effects*
  • Neutrophils / enzymology
  • Phospholipases A / physiology
  • Phospholipids / metabolism
  • Phosphorylation / drug effects
  • Protein Kinase Inhibitors
  • Protein Kinases / metabolism
  • Protein Processing, Post-Translational / drug effects*
  • Stimulation, Chemical
  • Tetradecanoylphorbol Acetate / pharmacology*


  • Enzyme Inhibitors
  • Ionophores
  • Leukotrienes
  • Membrane Lipids
  • Naphthalenes
  • Phospholipids
  • Protein Kinase Inhibitors
  • Arachidonic Acid
  • Calcimycin
  • Arachidonate 5-Lipoxygenase
  • Protein Kinases
  • Phospholipases A
  • calphostin C
  • Tetradecanoylphorbol Acetate
  • Calcium