ALOX5 phospho S523

Function

Catalyzes the oxygenation of arachidonate ((5Z,8Z,11Z,14Z)-eicosatetraenoate) to 5-hydroperoxyeicosatetraenoate (5-HPETE) followed by the dehydration to 5,6- epoxyeicosatetraenoate (Leukotriene A4/LTA4), the first two steps in the biosynthesis of leukotrienes, which are potent mediators of inflammation (PubMed:8631361, PubMed:21233389, PubMed:22516296, PubMed:24282679, PubMed:19022417, PubMed:23246375, PubMed:8615788, PubMed:24893149, PubMed:31664810). Also catalyzes the oxygenation of arachidonate into 8-hydroperoxyicosatetraenoate (8-HPETE) and 12-hydroperoxyicosatetraenoate (12-HPETE) (PubMed:23246375). Displays lipoxin synthase activity being able to convert (15S)-HETE into a conjugate tetraene (PubMed:31664810). Although arachidonate is the preferred substrate, this enzyme can also metabolize oxidized fatty acids derived from arachidonate such as (15S)-HETE, eicosapentaenoate (EPA) such as (18R)- and (18S)-HEPE or docosahexaenoate (DHA) which lead to the formation of specialized pro-resolving mediators (SPM) lipoxin and resolvins E and D respectively, therefore it participates in anti-inflammatory responses (PubMed:21206090, PubMed:31664810, PubMed:8615788, PubMed:17114001, PubMed:32404334). Oxidation of DHA directly inhibits endothelial cell proliferation and sprouting angiogenesis via peroxisome proliferator-activated receptor gamma (PPARgamma) (By similarity). It does not catalyze the oxygenation of linoleic acid and does not convert (5S)-HETE to lipoxin isomers (PubMed:31664810). In addition to inflammatory processes, it participates in dendritic cell migration, wound healing through an antioxidant mechanism based on heme oxygenase-1 (HO-1) regulation expression, monocyte adhesion to the endothelium via ITGAM expression on monocytes (By similarity). Moreover, it helps establish an adaptive humoral immunity by regulating primary resting B cells and follicular helper T cells and participates in the CD40-induced production of reactive oxygen species (ROS) after CD40 ligation in B cells through interaction with PIK3R1 that bridges ALOX5 with CD40 (PubMed:21200133). Also may play a role in glucose homeostasis, regulation of insulin secretion and palmitic acid-induced insulin resistance via AMPK (By similarity). Can regulate bone mineralization and fat cell differentiation increases in induced pluripotent stem cells (By similarity).

Pathway

Lipid metabolism; leukotriene A4 biosynthesis.

Post-translational modifications

Serine phosphorylation by MAPKAPK2 is stimulated by arachidonic acid (PubMed:11844797, PubMed:18978352). Phosphorylation on Ser-524 by PKA has an inhibitory effect (PubMed:15280375). Phosphorylation on Ser-272 prevents export from the nucleus (PubMed:11844797, PubMed:18978352). Phosphorylation at Ser-524 is stimulated by 8-bromo-3',5'-cyclic AMP or prostaglandin E2 (PubMed:26210919).

Sequence similarities

Belongs to the lipoxygenase family.

Cellular localization

• Cytoplasm
• Nucleus matrix
• Nucleus membrane
• Peripheral membrane protein
• Cytoplasm
• Perinuclear region
• Cytoplasm
• Cytosol
• Nucleus envelope
• Nucleus intermembrane space
• Shuttles between cytoplasm and nucleus (PubMed:19233132). Found exclusively in the nucleus, when phosphorylated on Ser-272 (PubMed:18978352). Calcium binding promotes translocation from the cytosol and the nuclear matrix to the nuclear envelope and membrane association (PubMed:19233132, PubMed:3118366, PubMed:8245774, PubMed:16275640).

Alternative names

• Polyunsaturated fatty acid 5-lipoxygenase
• Arachidonate 5-lipoxygenase
• 5-LO
• 5-lipoxygenase
• LOG5
• ALOX5

Database links

• swissprot:P09917

Target type

Proteins

Molecular weight

77983Da