5-lipoxygenase is phosphorylated by p38 kinase-dependent MAPKAP kinases.
5-lipoxygenase (5-LO) catalyzes the initial steps in the formation of leukotrienes, a group of inflammatory mediators derived from arachidonic acid (AA). Here we describe that activation of p38 mitogen-activated protein kinase in human polymorphonuclear leukocytes and in Mono Mac 6 cells leads to activation of downstream kinases, which can subsequently phosphorylate 5-LO in vitro. Different agents activated the 5-LO kinase activities, including stimuli for cellular leukotriene biosynthesis (A23187, thapsigargin, N-formyl-leucyl-phenylalanine), compounds that up-regulate the capacity for leukotriene biosynthesis (phorbol 12-myristate 13-acetate, tumor necrosis factor alpha, granulocyte/macrophage colony-stimulating factor), and well known p38 stimuli as sodium arsenite and sorbitol. For all stimuli, 5-LO kinase activation was counteracted by SB203580 (3 microM or less), an inhibitor of p38 kinase. At least two p38-dependent 5-LO kinase activities were found. Based on migration properties in in-gel kinase assays and immunoreactivity, one of these was identified as mitogen-activated protein kinase-activated protein kinase 2 (MAPKAP kinase 2). The other appeared to be MAPKAP kinase 3; however, it could not be excluded that also other p38-dependent kinases contributed. When polymorphonuclear leukocytes were incubated with sodium arsenite (strong activator of 5-LO kinases), platelet-activating factor and exogenous AA, there was a 4-fold increase in 5-LO activity as compared with incubations with only platelet-activating factor and AA. This indicates that 5-LO phosphorylation can be one factor determining cellular 5-LO activity.
Werz
O
O
Department of Medical Biochemistry and Biophysics, Division of Physiological Chemistry II Karolinska Institutet, S-171 77 Stockholm, Sweden.
Klemm
J
J
Samuelsson
B
B
Rådmark
O
O
D000595:Amino Acid Sequence; D000818:Animals; D001094:Arachidonate 5-Lipoxygenase / Q000737:chemistry / Q000378:metabolism*; D018053:Arsenites / Q000494:pharmacology; D000001:Calcimycin / Q000494:pharmacology; D002460:Cell Line; D006224:Cricetinae; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D007700:Kinetics; D051379:Mice; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000494:pharmacology; D009504:Neutrophils / Q000187:drug effects / Q000201:enzymology* / Q000502:physiology; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D051381:Rats; D011994:Recombinant Proteins / Q000378:metabolism; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D017670:Sodium Compounds / Q000494:pharmacology; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D019284:Thapsigargin / Q000494:pharmacology; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology; D048051:p38 Mitogen-Activated Protein Kinases; D000099190:MAP-Kinase-Activated Kinase 2
D001094:Arachidonate 5-Lipoxygenase; D018053:Arsenites; D000001:Calcimycin; D047908:Intracellular Signaling Peptides and Proteins; D020928:Mitogen-Activated Protein Kinases; D009240:N-Formylmethionine Leucyl-Phenylalanine; D017346:Protein Serine-Threonine Kinases; D011994:Recombinant Proteins; D017670:Sodium Compounds; D013755:Tetradecanoylphorbol Acetate; D019284:Thapsigargin; D014409:Tumor Necrosis Factor-alpha; D048051:p38 Mitogen-Activated Protein Kinases; D000099190:MAP-Kinase-Activated Kinase 2; C017947:sodium arsenite; C098416:MAP-kinase-activated kinase 3