FAM26F function and role in macrophages

摘要 离子通道、传输器、交换器和泵(这里称为ICT)控制着生活的大部分方面。他们有 广泛存在于神经元等可兴奋细胞中，在那里它们控制神经递质的释放 以及其他功能，以及心肌和骨骼肌细胞，在那里它们调节收缩的强度。 在大多数不可兴奋的细胞中，尤其是在免疫细胞中，ICT的特征很少。我们已经取得了 一种全球方法分析了600多个ICT在免疫细胞中的表达，并观察到其中一个 特定的ICT，命名为FAM26F，在促炎症的巨噬细胞中高度特异地表达 与其他免疫细胞相比。FAM26F是一种研究较少的离子通道，属于一个小家族 蛋白质(FAM26A至F)。最具特征的FAM26家族成员是FAM26C。它起着离子通道的作用 在某些实验条件下，并已被描述为促进细胞释放ATP。最近 已发表的FAM26F的低分辨率结构表明，它和FAM26C一样，也形成一个孔，并可能作为一个 离子通道。然而，到目前为止，我们的初步数据没有检测到FAM26F通道功能的证据 当在哺乳动物细胞中过度表达时。最可能的原因是FAM26F需要其他亚基或 相关蛋白质作为一个通道发挥作用，这是许多离子通道的特征。我们假设 而FAM26F的过度表达可能不足以产生功能通道和促炎作用 巨噬细胞不仅表达FAM26F，还表达形成通道所需的其他蛋白质。为了测试这一点 假设，在目标1中，我们将直接测量FAM26F的假定功能，如通道电流和 低分子分子的运输。在一种平行的方法中，我们将使用生化方法和质量 以鉴定巨噬细胞中与FAM26F相关的蛋白质。在目标2中，我们将阐明 FAM26F在巨噬细胞功能和炎症中的作用我们的初步数据显示，删除 FAM26F可损害巨噬细胞的某些促炎功能，如细胞因子的释放。这些 免疫信使蛋白对自身免疫性疾病类风湿性关节炎的疾病进展至关重要， 它们会导致关节发炎和破坏。因此，我们将使用巨噬细胞和小鼠 FAM26F已被删除，以确定FAM26F在细胞培养环境中对巨噬细胞功能的影响 在类风湿关节炎的小鼠模型中也是如此。这是Stefan Feske博士和William博士提出的多PI R03提案 Coetzee将他们独特的专业知识结合在一起，以更好地理解渠道的角色，尤其是 FAM26F，具有先天免疫力。目前还没有FDA批准的针对离子通道的药物 免疫紊乱和拟议研究的完成使我们朝着这个方向迈出了重要的一步。 这个错失的治疗机会。

Abstract Ion channels, transporters, exchangers and pumps (here called ICTs) control most aspects of life. They have been extensively characterized in excitable cells, such as neurons, where they control neurotransmitter release and other functions as well as cardiac and skeletal muscle cells, where they regulate the strength of contraction. In most non-excitable cells, and specifically in immune cells, ICTs are only scantly characterized. We have taken a global approach to analyze the expression of more than 600 ICTs in immune cells, and observed that one particular putative ICT, named FAM26F, is highly and specifically expressed in proinflammatory macrophages compared to other immune cells. FAM26F is an understudied ion channel that belongs to a small family of proteins (FAM26A to F). The best characterized FAM26 family member is FAM26C. It functions as an ion channel under certain experimental conditions and has been described to promote ATP release from cells. Recently published low resolution structures of FAM26F show that it, like FAM26C, also forms a pore and may act as an ion channel. Our preliminary data to date, however, did not detect evidence for channel function of FAM26F when overexpressed in mammalian cells. The most likely reason is that FAM26F needs other subunits or associated proteins to function as a channel, which is characteristic of many ion channels. We hypothesize that while overexpression of FAM26F may not be sufficient to generate a functional channel, and proinflammatory macrophages express not only FAM26F but also the other proteins required to form a channel. To test this hypothesis, we will in Aim 1 directly measure putative functions of FAM26F such as channel currents and the transport of low molecular weight molecules. In a parallel approach, we will use biochemical methods and mass spectrometry to identify the proteins that associate with FAM26F in macrophages. In Aim 2, we will elucidate the role of FAM26F in macrophage function and inflammation. Our preliminary data have shown that deletion of FAM26F impairs certain proinflammatory functions of macrophages such as the release of cytokines. These immune messenger proteins are critical for disease progression in the autoimmune disease rheumatoid arthritis, where they drive joint inflammation and destruction. We will therefore use macrophages and mice in which FAM26F has been deleted to determine the effects of FAM26F on macrophage function in cell culture settings and in mouse models of rheumatoid arthritis. This multi-PI R03 proposal by Drs. Stefan Feske and William Coetzee brings together their unique expertise to better understand the roles of channels, and in particular FAM26F, in innate immunity. There are currently no FDA approved drugs that target ion channels for immunological disorders and the completion of the proposed studies takes us an important step in the direction of this missed therapeutic opportunity.