| An Affinity-directed Protein Missile (AdPROM) System for Targeted Destruction of Endogenous Proteins
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Author:
Date:
2017-11-20
[Abstract] We recently reported an Affinity-directed PROtein Missile (AdPROM) system for the targeted proteolysis of endogenous proteins of interest (POI) (Fulcher et al., 2016 and 2017). AdPROM consists of the Von Hippel Lindau (VHL) protein, a Cullin 2 E3 ligase substrate receptor (Bosu and Kipreos, 2008), conjugated to a high affinity polypeptide binder (such as a camelid nanobody) that recognises the target protein in cells. When introduced in cells, the target protein is recruited to the CUL2 E3 ubiquitin ligase complex for ubiquitin-mediated proteasomal degradation. For target protein recruitment, we have utilised both camelid-derived VHH domain nanobodies as well as synthetic polypeptide monobodies based on the human type III fibronectin domain (Sha et al., 2013; Fridy et ...
[摘要] 我们最近报道了一种针对内源性感兴趣蛋白（POI）的靶向蛋白水解的亲和指导PROtein导弹（AdPROM）系统（Fulcher等人，2016和2017）。 AdPROM由Von Hippel Lindau（VHL）蛋白组成，Cullin 2 E3连接酶底物受体（Bosu and Kipreos，2008），与识别细胞中靶蛋白的高亲和力多肽结合剂（如骆驼科纳米抗体）缀合。当在细胞中引入时，靶蛋白质被招募到CUL2 E3泛素连接酶复合体用于泛素介导的蛋白酶体降解。对于靶蛋白的募集，我们使用了基于人类III型纤连蛋白结构域的骆驼科动物来源的VHH结构域纳米抗体以及合成多肽单体（Sharm等人，2013; Fridy等人。，2014; Schmidt et al。，2016）。在此协议中，我们描述了生成AdPROM构建体及其在人细胞系中用于靶蛋白质破坏的详细方法。 AdPROM允许对POI进行功能表征，并且其目标蛋白质破坏的效率克服了RNA干扰方法的许多局限性，这些方法需要长时间的治疗并与脱靶效应相关联，而CRISPR / Cas9基因编辑并不总是可行的。
【背景】该协议使人们能够在哺乳动物细胞系中设计，构建和表达AdPROM VHL-nano ...
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| Determination of Cellular Phosphatidylinositol-3-phosphate (PI3P) Levels Using a Fluorescently Labelled Selective PI3P Binding Domain (PX)
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Author:
Date:
2016-08-20
[Abstract] The lipid Phosphatidylinositol-3-phosphate [PtdIns3P or PI(3)P] plays many membrane trafficking roles and is primarily produced by the Class III PI3K, VPS34. Determining the level of cellular PI(3)P however can be complex. Extraction of cellular lipids by methanol/chloroform can struggle to separate and identify distinct phospholipid species. Alternately mass spectrometry may be utilised but this requires significant set up of specialised equipment and time to utilise.
Use of a PI(3)P-binding-specific recombinant protein domain is a quick method for ascertaining cellular PI(3)P levels and can also allow visualisation of sub-cellular localisation. The PX domain of p40phox (herein referred to as PX) is very specific for PI(3)P over other phospholipid species (Kanai et al., ...
[摘要] 脂质磷脂酰肌醇-3-磷酸[PtdIns3P或PI（3）P]扮演许多膜贩运角色，主要由III类PI3K，VPS34产生。然而，确定细胞PI（3）P的水平可以是复杂的。通过甲醇/氯仿提取细胞脂质可能难以分离和鉴定不同的磷脂种类。或者可以使用质谱法，但这需要大量设置专门的设备和时间来利用。
使用PI（3）P结合特异性重组蛋白结构域是用于确定细胞PI（3）P水平的快速方法，并且还可以允许亚细胞定位的可视化。 p40phox的PX结构域（本文称为PX）对PI（3）P比其它磷脂种类非常特异（Kanai等人，2001）。然而，在细胞中直接表达PX可能是有问题的，因为它将以显性负性方式作用，以比内源蛋白更大的亲和力结合和螯合PI（3）P，从而干扰细胞途径和PI（3）P水平。因此，使用荧光标记的PX后细胞固定更合适，因为它能突出显示PI（3）富集结构，没有扰乱系统的风险。
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| Determination of VPS34/PIK3C3 Activity in vitro Utilising 32P-γATP
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Author:
Date:
2016-08-20
[Abstract] VPS34 is the only class III phosphatidylinositol-3-kinase (PI3K) in mammalian cells and produces the vast majority of cellular phosphatidylinositol-3-phosphate [PI(3)P]. PI(3)P is a key signalling lipid that plays many membrane trafficking roles in processes such as endocytosis and autophagy. VPS34 is a key cellular regulator, loss of function can have catastrophic effects and is embryonic lethal (Zhou et al., 2011). The levels of cellular PI(3)P can be determined by fluorescent staining techniques and can be used to monitor effects upon VPS34 activity, however it is important to verify that any changes are mediated by VPS34, particularly as alternate pathways of PI(3)P production are possible such as via class II PI3Ks (Devereaux et al., 2013). Assaying VPS34 activity ...
[摘要] VPS34是哺乳动物细胞中唯一的III类磷脂酰肌醇-3-激酶（PI3K），并且产生绝大多数细胞磷脂酰肌醇-3-磷酸[PI（3）P]。 PI（3）P是一个关键的信号脂质，在诸如内吞作用和自噬的过程中起许多膜运输的作用。 VPS34是关键的细胞调节剂，功能丧失可具有灾难性作用并且是胚胎致死的（Zhou等人，2011）。 细胞PI（3）P的水平可以通过荧光染色技术确定，并且可以用于监测对VPS34活性的影响，然而重要的是验证任何变化由VPS34介导，特别是作为PI（3）的替代途径， P生产是可能的，例如通过II类PI3K（Devereaux等人，2013）。 直接在体外测定VPS34活性可以是描绘特定刺激的作用的关键阶段。
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