The Macromolecular Organization of Leukotriene Synthesis and Renal Inflammation

描述(由申请人提供)：白三烯(LT)是从花生四烯酸(AA)底物衍生的二十烷类生物活性信号分子家族的成员。它是一种脂质信号分子，有助于启动和放大先天和获得性免疫反应。它是哮喘和过敏性鼻炎的媒介，临床研究和利用基因敲除动物的生物合成酶和受体的研究证明了这一点。最近，它们被认为与动脉粥样硬化的慢性血管炎症有关。LTS B4、C4、D4和E4在炎症组织中募集和激活白细胞，并调节内皮细胞、血管和气道平滑肌的功能。LTC4的形成需要核膜上至少四种蛋白质的功能相互作用，LTC4是母体半胱氨酰LT。它们是胞浆磷脂酶A2(CPLA2)、5-脂氧合酶(5-LO)、5-脂氧合酶激活蛋白(FLAP)和LTC4合成酶；LTA4水解酶(LTA4-H)代谢LTA4产生LTB4。最近，我们发现5-LO、FLOW和LTC4合成酶被组装在核膜上的新型大分子复合体中，启动LT的合成。这些复合体包括一个额外的翻盖相关蛋白，相关蛋白-10 kDa(AP-10)和其他蛋白质。AP-10从瓣上解离并形成复合体，这表明它在LT的形成中具有重要的调节作用。然而，既不知道它的身份，也不知道控制它从襟翼上解离的信号。启动和维持5-LO与FLOW的联系的细胞内信号以及复合体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膜靶向5-LO及其与皮瓣结合所必需的。或者，5-LO向核膜的移动和其在LT膜合成中的掺入可能受到单独的控制。这项建议的广泛、长期目标是确定如何调节LT膜合成复合体的组装，并确定每个成分及其作用。

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.