The Macromolecular Organization of Leukotriene Synthesis and Renal Inflammation

描述（由申请人提供）：白三烯（LT）是衍生自底物花生四烯酸（AA）的生物活性信号分子类花生酸家族的成员。LT是脂质信号传导分子，有助于先天性和适应性免疫应答的启动和扩增。LT是哮喘和过敏性鼻炎的介质，如临床研究和使用生物合成酶和受体敲除动物的研究所证明的。最近，它们被认为与动脉粥样硬化的慢性血管炎症有关。LT B4、C4、D4和E4的功能是募集和激活炎症组织中的白细胞，并且还调节内皮细胞以及血管和气道平滑肌的功能。LTC 4的形成需要核膜上至少四种蛋白质的功能相互作用。它们是胞质磷脂酶A2（cPLA 2）、5-脂氧合酶（5-LO）、5-脂氧合酶激活蛋白（FLAP）和LTC 4合酶; LTA 4通过LTA 4水解酶（LTA 4-H）代谢产生LTB 4。最近，我们已经表明，5-LO，FLAP，和LTC 4合酶组装在核膜上的新型大分子复合物启动LT合成。这些复合物包括额外的FLAP相关蛋白，相关蛋白-10 kDa（AP-10）和其他蛋白。AP-10从FLAP中解离，同时形成复合物，这表明它在LT形成中具有重要的调节作用。然而，它的身份和控制其从FLAP解离的信号都是未知的。启动和维持5-LO与FLAP结合的细胞内信号以及复合物的整体组装尚不清楚。一种可能性是持续的细胞内钙水平是5-LO的膜靶向及其与FLAP的关联所必需的。或者，5-LO向核膜的移动及其掺入LT膜合成物中可能处于单独的控制下。该提案的广泛，长期目标是确定LT膜合成复合物的组装是如何调节的，并确定每个组件及其作用。

DESCRIPTION (provided by applicant): Leukotrienes (LTs) are members of the eicosanoid family of bioactive signaling molecules derived from the substrate arachdonic acid (AA). LTs are lipid signaling molecules that contribute to the initiation and amplification of the innate and adaptive immune responses. LTs are mediators of asthma and allergic rhinitis, as demonstrated by clinical studies, and studies using knockout animals for the biosynthetic enzymes and receptors. Recently, they have been implicated in the chronic vascular inflammation of atherosclerosis. LTs B4, C4, D4 and E4 function to recruit and activate leukocytes in inflamed tissue, and also regulate the function of endothelial cells, and vascular and airway smooth muscle. The formation of LTC4, the parent cysteinyl LT, requires the functional interaction of at least four proteins on the nuclear envelope. These are cytosolic phospholipase A2 (cPLA2), 5-lipoxygenase (5-LO), the 5- lipoxygenase-activating protein (FLAP), and LTC4 synthase; the metabolism of LTA4 by LTA4 hydrolase (LTA4-H) yields LTB4. Recently, we have shown that 5-LO, FLAP, and LTC4 synthase are assembled in novel macromolecular complexes on the nuclear envelope to initiate LT synthesis. These complexes include an additional FLAP-associated protein, Associated Protein-10 kDa (AP-10), and other proteins. AP-10 dissociates from FLAP concurrent with complex formation, suggesting it has an important regulatory role in LT formation. However, neither its identity nor the signals controlling its dissociation from FLAP are known. The intracellular signals that initiate and sustain the association of 5-LO with FLAP and also the overall assembly of the complex are unknown. One possibility is that sustained intracellular calcium levels are required for both membrane targeting of 5-LO and its association with FLAP. Alternatively, the movement of 5-LO to the nuclear envelope and its incorporation into LT membrane synthetic may be under separate controls. The broad, long-term objective of this proposal is to determine how the assembly of LT membrane synthetic complexes is regulated and to identify each of the components and their roles.