5-Lipoxygenase: mechanisms of regulation

Rådmark, Olof; Samuelsson, Bengt

doi:10.1194/jlr.r800062-jlr200

Cited by 143 publications

(129 citation statements)

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“…Our results showed that EGR-1 siRNA was effective in reducing PlGF-mediated 5-LO and FLAP mRNA expression. The role of Egr-1 in 5-LO transcription is consistent with the presence of several GC-boxes in the human 5-LO gene promoter that are proximal to the transcription start site and are recognized by transcription factors Sp1 and Egr-1 (34,38). However, PlGF-induced FLAP mRNA expression was attenuated by both EGR-1 siRNA and HIF-1␣ siRNA, indicating direct or indirect roles of these transcription factors.…”

Section: Discussionsupporting

confidence: 66%

Placenta Growth Factor-induced Early Growth Response 1 (Egr-1) Regulates Hypoxia-inducible Factor-1α (HIF-1α) in Endothelial Cells

Patel¹,

Kalra

2010

Journal of Biological Chemistry

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Leukotrienes, the lipid inflammatory products derived from arachidonic acid, are involved in the pathogenesis of respiratory and cardiovascular diseases and reactive airway disease in sickle cell disease. Placenta growth factor (PlGF), elaborated from erythroid cells, increased the mRNA expression of 5-lipoxygenase and 5-lipoxygenase-activating protein (FLAP) in human pulmonary microvascular endothelial cells. PlGF-induced both promoter activity and mRNA expression of hypoxia-inducible factor-1␣ (HIF-1␣), which was abrogated by early growth response-1 (EGR-1) small interfering RNA. PlGF showed a temporal reciprocal relationship in the mRNA levels of EGR-1 and NAB2, the latter a repressor of Egr-1. Moreover, Nab2, but not mutant Nab2, significantly reduced promoter activity and mRNA expression of HIF-1␣ and also reduced expression of the HIF-1␣ target gene FLAP. Furthermore, overexpression of Egr-1 led to increased promoter activities for both HIF-1␣ and FLAP in the absence of PlGF. Additionally, the Egr-1-mediated induction of HIF-1␣ and FLAP promoters was reduced to basal levels by EGR-1 small interfering RNA. The binding of Egr-1 to HIF-1␣ promoter was corroborated by electrophoretic mobility shift assay and chromatin immunoprecipitation assay, which showed increased Egr-1 binding to the HIF-1␣ promoter in response to PlGF stimulation. These studies provide a novel mechanism for PlGF-mediated regulation of HIF-1␣ via Egr-1, which results in increased FLAP expression. This study provides a new therapeutic target, namely Egr-1, for attenuation of elevated leukotriene levels in patients with sickle cell disease and other inflammatory diseases.

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Section: Discussionsupporting

confidence: 66%

Placenta Growth Factor-induced Early Growth Response 1 (Egr-1) Regulates Hypoxia-inducible Factor-1α (HIF-1α) in Endothelial Cells

Patel¹,

Kalra

2010

Journal of Biological Chemistry

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“…As shown in Fig. S1, positions Y42 and Y53 seem to be very close to the membrane interacting tryptophanes (W13, W75, W102) and the calcium binding loop of 5-LO (N43, D44, E46), which are both important for activation mediated translocation of 5-LO to the membrane [3]. Furthermore, Y445 interacts with the loop in which R518 is located, which is part of a nuclear import sequence and near the phosphorylation site S523 (Fig.…”

Section: Discussionmentioning

confidence: 99%

“…S3). 5-LO is upregulated in MM6 cells after cell differentiation (TGF-b and 1a,25-dihydroxyvitamin D 3 ) and, since it was seen phosphorylated at Ser271 without further treatment, it seems that the phosphorylation event is not connected to a specific stimulus for 5-LO activity but is rather constitutive. However, the signal intensity for the phosphopeptide in the mass spectra was low and the enrichment procedure was not successful for many of the examined samples.…”

Section: Maldi-ms Analysis Of Immunoprecipitated Samples From Mm6 Cellsmentioning

confidence: 99%

“…5-LO is currently intensively studied as a drug target [2]. Regulation of 5-LO expression and activity, including post translational modifications (PTMs) as well as possible interactions with other proteins, are particularly interesting subjects for better understanding of various diseases [3,4].…”

mentioning

confidence: 99%

“…Furthermore, the regulation of expression and activation of 5-LO and Src kinases shows a notable analogy. Stimuli such as transforming growth factor b (TGF-b), 1a,25-dihydroxyvitamin D 3 , retinoic acid and dimethylsulfoxide, which are known to upregulate 5-LO expression [15], also upregulate Src kinase expression [16][17][18], and factors that can prime or activate 5-LO, like N-formyl-Met-Leu-Phe (fMLP), Ca 2+ -ionophore A23187, lipopolysaccharide (LPS) and phorbol-12-myristate-13-acetate (PMA) [7], are known activators of Src kinases [19][20][21][22][23].…”

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confidence: 99%

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Analysis of 5‐lipoxygenase phosphorylation on molecular level by MALDI‐MS

et al. 2014

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The enzyme 5-lipoxygenase (5-LO) catalyzes the first reactions in the biosynthesis of leukotrienes, powerful lipid mediators that are involved in several physiological and pathological processes. 5-LO activity is tightly regulated by several factors, including post translational modifications (PTMs). Phosphorylations of 5-LO by the kinases extracellular signal-regulated kinase 2 (Erk2), mitogen-activated protein kinase activated protein kinase 2 (MK2) and protein kinase A (PKA) have been described to regulate 5-LO activity. Furthermore, 5-LO phosphorylation is considered a determinant of drug candidate potency. However, no evidence on a molecular level, as can be provided by MS, has as yet been presented for these PTMs. Here, we employ a workflow including different proteolytic cleavages and phosphopeptide enrichment for detection of 5-LO phosphorylation by MALDI-MS. Proof for the known phosphorylation sites of MK2 (Ser271) and PKA (Ser523) was provided by MS after in vitro phosphorylation, but not for the postulated Erk2 site (Ser663). Detection limits have been determined for all three sites. Moreover, we identified novel tyrosine kinase target sites within 5-LO using in silico and in vitro methods. Tyr42, Tyr53 and either Tyr94 or Tyr445 were phosphorylated by the Src kinases Fgr, hematopoietic cell kinase (HCK) and Yes. To analyze the phosphorylation state in the cellular context, we created stably 5-LO-transduced Mono Mac 6 cells. Here, we only detected phospho-Ser271 by MS, whereas immunoblot analysis indicated tyrosine phosphorylation, phospho-Ser271 and phospho-Ser663. Unexpectedly, phospho-Ser271 occurred independent of cell stimulation. Taken together, we describe a method for the molecular analysis of 5-LO phosphorylation, provide insights regarding the occurrence of known phosphorylation sites partly in contrast to earlier studies and present first evidence on novel phosphosites.

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Lipoxygenase Pathway of the Arachidonate Cascade

Kobe

Newcomer

2013

Encyclopedia of Life Sciences

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Lipoxygenases (LOXs) are iron‐containing enzymes that catalyse the peroxidation of polyunsaturated fatty acids. In mammals, LOX products and their metabolites are potent lipid mediators that provoke diverse biological responses. These eicosanoids, derived from arachidonic acid, play important roles in inflammation and the resolution of inflammation. Moreover, they have been implicated in the development of cardiovascular disease. Although several LOX isoforms are expressed in individual organisms, each generates a specific product. How structurally and mechanistically related enzymes generate different products from a common substrate is not fully understood. In addition, the biological effects of many of the lipid mediators produced through LOX pathways remain to be uncovered. Key Concepts: Arachidonic acid is a substrate for lipoxygenases, iron enzymes that catalyse the peroxidation of polyunsaturated fatty acids. Mammalian lipoxygenases transform the common substrate (arachidonic acid) to a unique stereo‐ and regiospecific product. Leukotriene synthesis is initiated by 5‐lipoxygenase. Lipoxygenase products and their downstream metabolites are potent signalling molecules, some of which play roles in inflammation or its resolution. Lipoxygenase products are associated with cardiovascular diseases, but their molecular mechanism of action remains unclear.

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5-Lipoxygenase: mechanisms of regulation

Cited by 143 publications

References 53 publications

Placenta Growth Factor-induced Early Growth Response 1 (Egr-1) Regulates Hypoxia-inducible Factor-1α (HIF-1α) in Endothelial Cells

Placenta Growth Factor-induced Early Growth Response 1 (Egr-1) Regulates Hypoxia-inducible Factor-1α (HIF-1α) in Endothelial Cells

Analysis of 5‐lipoxygenase phosphorylation on molecular level by MALDI‐MS

Lipoxygenase Pathway of the Arachidonate Cascade

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