FIGURE 1:

Assembly of the LT synthetic complex and the initiation of LT synthesis. Under resting conditions, cPLA₂ and 5-LO reside in the cytoplasm of neutrophils. Transmembrane cell activation results in an increase in intracellular calcium leading to the translocation of 5-LO to the nuclear membrane, where it associates with FLAP. Concomitantly, cPLA₂ traffics to the nuclear membrane/ER, where it releases free AA from phospholipids. 5-LO, FLAP, and AA assemble together at the correct time on the nuclear membrane, making up the core of the LT biosynthetic complex. LTA₄ is subsequently converted to LTB₄ by soluble LTA₄ hydrolase.