The Intracellular Localisation and Phosphorylation Profile of the Human 5-Lipoxygenase Δ13 Isoform Differs from That of Its Full Length Counterpart

摘要: 5-Lipoxygenase (5-LO) catalyzes leukotriene (LT) biosynthesis by a mechanism that involves interactions with 5-lipoxygenase activating protein (FLAP) and coactosin-like (CLP). 5-LO splice variants were recently identified in human myeloid lymphoid cells, including the catalytically inactive ∆13 isoform (5-LO∆13) whose transcript lacks exon 13. 5-LO∆13 inhibits product when co-expressed active full length (5-LO1). The objective of this study was to investigate potential mechanisms which interferes transfected HEK293 cells. When 5-LO1, inhibited LT but not 5-hydroxyeicosatetraenoic acid (5-HETE) biosynthesis. This inhibition independent 5-LO∆13—FLAP since it occurred cells expressing FLAP or not. In cell-free assays CLP enhances activity through tryptophan-102 5-LO. current study, requirement for W102 extended whole as 5-LO1-W102A mutant produced little products. W102A mutants effectively suggesting is CLP. Confocal microscopy showed 5-LO1 primarily nucleoplasm whereas diffuse cellular expression. Despite retention known nuclear localisation sequences, cytosolic concentrated ER-rich perinuclear regions where its effect on may occur. same pattern. Consistent subcellular distribution patterns, hyper-phosphorylated S523 S273 compared 5-LO1. Together, these results reveal role targeting are required localization an initial characterisation appears FLAP. Better knowledge regulation properties alternative isoforms will contribute understanding complex