| Quantification of the Surface Expression of G Protein-coupled Receptors Using Intact Live-cell Radioligand Binding Assays
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Author:
Date:
2020-09-20
[Abstract] G protein-coupled receptors (GPCRs) are the most structurally diverse family of signaling proteins and regulate a variety of cell function. For most GPCRs, the cell surface is their functional destination where they are able to respond a wide range of extracellular stimuli, leading to the activation of intracellular signal transduction cascades. Thus, the quantity of receptor expression at the cell surface is a crucial factor regulating the functionality of the receptors. Over the past decades, many methods have been developed to measure the cell surface expression of GPCRs. Here, we describe an intact live-cell radioligand binding assay to quantify the surface expression of GPCRs at the endogenous levels or after overexpression. In this assay, cell cultures will be incubated with ...
[摘要] [摘要] G蛋白偶联受体（GPCR）是信号蛋白中结构最多样化的家族，可调节多种细胞功能。对于大多数GPCR，细胞表面是它们的功能目的地，能够响应广泛的细胞外刺激，从而激活细胞内信号转导级联反应。因此，受体在细胞表面的表达量是调节受体功能的关键因素。在过去的几十年中，已开发出许多方法来测量GPCR的细胞表面表达。在这里，我们描述了完整的活细胞放射性配体结合测定法，以量化内源水平或过表达后GPCR的表面表达。在该测定中，将细胞培养物与特定的细胞不可渗透的放射性配体温育，所述放射性不可配体选择性地和化学计量地结合至各个GPCR，并且通过受体结合的配体的放射性来定量细胞表面的受体数量。 此方法对于测量完整活细胞表面的功能性GPCR具有高度特异性，对于内源性，低丰度的GPCR特别有用。
[背景 ] G蛋白偶联受体（GPCR）构成细胞表面受体的最大超家族，并在生理和病理条件下调节多种细胞功能（Hauser 等人，2017; Hilger 等人，2018; Weinberg和Puthenveedu，2019） ...
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| Preparation of HeLa Total Membranes and Assay of Lipid-inhibition of Serine Palmitoyltransferase Activity
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Author:
Date:
2020-06-20
[Abstract] Serine palmitoyltranferase (SPT) is a pyridoxal 5′ phosphate (PLP)-dependent enzyme that catalyzes the first and rate-limiting step of de novo synthesis of sphingolipids. SPT activity is homeostatically regulated in response to increased levels of sphingolipids. This homeostatic regulation of SPT is mediated through small ER membrane proteins termed the ORMDLs. Here we describe a procedure to assay ORMDL dependent lipid inhibition of SPT activity. The assay of SPT activity using radiolabeled L-serine was developed from the procedure established by the Hornemann laboratory. The activity of SPT can also be measured using deuterated L-serine but it requires mass spectrometry, which consumes money, time and instrumentation. The ORMDL dependent lipid inhibition of SPT activity can be ...
[摘要] [摘要] 丝氨酸Palmitoyltranferase （SPT）是吡哆醛5 ' 磷酸（PLP）依赖酶催化第一和限速步骤中从头合成鞘脂。SPT活动是Homeostatically调控响应水平的提高鞘脂。这SPT的稳态调节是通过小ER膜蛋白介导称为ORMDLs。在这里，我们描述了一种方法用放射性标记的L-丝氨酸以测定SPT活性的SPT活性。测定的ORMDL依赖性抑制脂质从由规定的程序被开发Hornemann 实验室。 SPT的活性也可以使用氘化的L-丝氨酸进行测定，但需要进行质谱分析，这会耗费金钱，时间和仪器。可以在细胞和无细胞系统中研究ORMDL依赖性脂质对SPT活性的抑制作用。在这里，我们提供了详细的协议来测量存在短链（C8-神经酰胺）或长链神经酰胺（C24-神经酰胺）时SPT活性。该协议的最大优势之一我们通过在HeLa细胞膜中提供外源鞘氨醇和24：1酰基辅酶A通过内源性神经酰胺合酶生成长链神经酰胺来实现这一目标。需要精密的仪器。
[背景 ] 丝氨酸palmit oyltranferase （SPT）是一种多亚基酶是在真核生物和原核生物一些广泛表达（花田等人，1997; Ikushiro 。等人，2001; Hornemann 等人，2007）.The ...
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| High-throughput Flow Cytometry Assay to Investigate TDP43 Splicing Function
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Author:
Date:
2020-04-20
[Abstract] Mutations in RNA-binding proteins (RBPs) such as TDP43 are associated with transcriptome-wide splicing defects and cause severe neurodegenerative diseases, including amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). The impact of RBP mutations on splicing function is routinely studied using PCR-based bulk measurements. However, the qualitative and low-throughput nature of this assay make quantitative and systematic analyses, as well as screening approaches, difficult to implement. To overcome this hurdle, we have developed a quantitative, high-throughput flow cytometry assay to investigate TDP43 splicing function on a single-cell level
[摘要] [摘要 ] TDP43等RNA结合蛋白（RBP）突变与转录组范围的剪接缺陷相关，并引起严重的神经退行性疾病，包括肌萎缩性侧索硬化症（ALS）和额颞痴呆（FTD）。RBP突变对剪接的影响通常使用基于PCR的大量测量方法来研究其功能。但是，该方法的定性和低通量性质使得难以进行定量和系统的分析以及筛选方法。为克服这一障碍，我们开发了定量，高通量流式细胞仪检测单细胞水平的TDP43剪接功能
[背景 ] RNA结合蛋白（RBPs）（例如TDP43）通过协调RNA的稳定性，转运和加工（包括mRNA剪接）来调节转录后基因的调控（Gerstberger 等，2014）。突变和/导致RBP功能受损或聚集与许多神经退行性疾病的病因有关，例如肌萎缩性侧索硬化症（ALS）和额颞痴呆（FTD）（Harrison and Shorter，2017）。值得注意的是，与RBPs相关的ALS相关突变如TDP43可以引起转录组范围的剪接。缺陷，提示RBP剪接功能的失调可能是疾病的关键驱动因素（Arnold 等，2013; Sun 等，2015）。因此，ALS研究的一个重要目标是揭示RBP功能的分子机制，需要实验方法来系统询问RBP剪接功能。
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