Phosphorylation of serine 271 on 5-lipoxygenase and its role in nuclear export

J Biol Chem. 2009 Jan 2;284(1):306-313. doi: 10.1074/jbc.M805593200. Epub 2008 Nov 1.


The enzyme 5-lipoxygenase (5-LO) initiates the biosynthesis of leukotrienes, inflammatory mediators involved in immune diseases and defense. The subcellular localization of 5-LO is regulated, with nuclear import commonly leading to increased leukotriene production. We report here that 5-LO is constitutively phosphorylated on Ser-271 in transfected NIH 3T3 cells. This residue is nested in a classical nuclear export sequence, and phosphorylated Ser-271 5-LO was exclusively found in the nucleus by immunofluorescence and by fractionation techniques. Mutation of Ser-271 to Ala allowed nuclear export of 5-LO that was blocked by the specific nuclear export inhibitor leptomycin b, suggesting that phosphorylation of Ser-271 serves to interfere with exportin-1-mediated nuclear export. Consistent with previous reports that purified 5-LO can be phosphorylated on Ser-271 in vitro by MAPK-activated protein kinase 2, the nuclear export of 5-LO was increased by either treatment with the p38 inhibitor SB 203,580 or co-expression of a kinase-deficient p38 MAPK. Nuclear export of 5-LO can also be induced by KN-93, an inhibitor of Ca2+/calmodulin-dependent kinase II, and the effects of SB 203,580 plus KN-93 are additive. Finally, HeLa cells, which lack nuclear 5-LO, also lack constitutive phosphorylation of Ser-271. Taken together, these results indicate that the phosphorylation of Ser-271 serves to inhibit the nuclear export of 5-LO. This action works in concert with nuclear import, which is regulated by phosphorylation on Ser-523, to determine the subcellular distribution of 5-LO, which in turn regulates leukotriene biosynthesis.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Active Transport, Cell Nucleus / drug effects
  • Active Transport, Cell Nucleus / physiology
  • Amino Acid Substitution
  • Animals
  • Arachidonate 5-Lipoxygenase / genetics
  • Arachidonate 5-Lipoxygenase / metabolism*
  • Benzylamines / pharmacology
  • Calcium-Calmodulin-Dependent Protein Kinase Type 2 / antagonists & inhibitors
  • Calcium-Calmodulin-Dependent Protein Kinase Type 2 / genetics
  • Calcium-Calmodulin-Dependent Protein Kinase Type 2 / metabolism
  • Cell Nucleus / enzymology*
  • Cell Nucleus / genetics
  • Cricetinae
  • Dogs
  • Humans
  • Imidazoles / pharmacology
  • Leukotrienes / biosynthesis
  • Leukotrienes / genetics
  • MAP Kinase Kinase 2 / antagonists & inhibitors
  • MAP Kinase Kinase 2 / genetics
  • MAP Kinase Kinase 2 / metabolism
  • Mice
  • Mutation, Missense
  • NIH 3T3 Cells
  • Nuclear Export Signals / physiology*
  • Opossums
  • Protein Kinase Inhibitors / pharmacology
  • Pyridines / pharmacology
  • Rabbits
  • Rats
  • Serine / genetics
  • Serine / metabolism
  • Sulfonamides / pharmacology
  • p38 Mitogen-Activated Protein Kinases / antagonists & inhibitors
  • p38 Mitogen-Activated Protein Kinases / genetics
  • p38 Mitogen-Activated Protein Kinases / metabolism


  • Benzylamines
  • Imidazoles
  • Leukotrienes
  • Nuclear Export Signals
  • Protein Kinase Inhibitors
  • Pyridines
  • Sulfonamides
  • KN 93
  • Serine
  • Arachidonate 5-Lipoxygenase
  • Calcium-Calmodulin-Dependent Protein Kinase Type 2
  • p38 Mitogen-Activated Protein Kinases
  • MAP Kinase Kinase 2
  • SB 203580