(*contributed equally to this work) 发布: 2020年03月05日第10卷第5期 DOI: 10.21769/BioProtoc.3537 浏览次数: 4344
评审: Ralph Thomas BoettcherAnonymous reviewer(s)
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高灵敏且可调控的 ATOM 荧光生物传感器:用于检测细胞中蛋白质靶点的亚细胞定位
Harsimranjit Sekhon [...] Stewart N. Loh
2025年03月20日 1361 阅读
Abstract
Protein sorting at the trans Golgi network (TGN) plays important roles in targeting newly synthesized proteins to their specific destinations. The aim of this proposal is to reconstitute the packaging of non-Golgi resident cargo proteins into vesicles at the TGN, utilizing rat liver cytosol, semi-intact mammalian cells and nucleotides. The protocol describes how to perform the vesicle formation assay, how to isolate vesicles and how to detect cargo proteins in vesicles. This reconstitution assay can be used to quantitatively measure the efficiency of the packaging of a specific cargo protein into transport vesicles at the TGN under specific experimental conditions.
Keywords: TGN (反面高尔基体网状结构)Background
The trans Golgi network (TGN) is an essential transport hub in the secretory transport pathway. To ensure the fidelity of vesicular trafficking, eukaryotic cells employ a variety of protein sorting machineries to accurately package specific cargo proteins into transport vesicles at the TGN which are then delivered to specific destinations (Guo et al., 2014). To deepen our understanding of the specificity of the TGN sorting process, it is important to develop an assay that can faithfully reconstitute the vesicle formation and cargo sorting process at the TGN. This assay can be utilized to directly and quantitatively measure the roles of a specific factor in regulating the packaging of a specific cargo protein into transport vesicles. Cell-free reconstitution of the packaging of cargo proteins into COPII vesicles from the endoplasmic reticulum (ER) has been well established (Kim et al., 2005; Kim et al., 2007; Merte et al., 2010; Yuan et al., 2018; Niu et al., 2019;). An in vitro assay that reconstitutes the release of a specific cargo protein, TGN46, into transport vesicles at the TGN has been developed (Ponnambalam et al., 1996; Wakana et al., 2012). TGN46 is mainly localized at the TGN, although it can cycle between the TGN and the plasma membrane (Ponnambalam et al., 1996). Recently, we devised an alternative vesicle budding protocol to reconstitute the packaging of non-Golgi resident cargo proteins into vesicles at the TGN (Ma et al., 2018). We performed the vesicle formation assay by incubating cells at 20 °C to accumulate newly synthesized cargo proteins at the TGN and performed the budding reaction in the presence of the GTPase defective mutant, Sar1A(H79G), to inhibit packaging of cargo proteins into Coat Protein Complex II (COPII) vesicles at the ER. Moreover, we utilized floatation to efficiently remove cytosolic proteins that are not associated with vesicles (Figure 1). Using this assay, we have reconstituted release of planar cell polarity proteins, Vangl2 and Frizzled6, from the TGN (Ma et al., 2018). Our assay indicates that the tyrosine sorting motif on Vangl2 and the polybasic sorting motif on Frizzled6 are important for packaging into vesicles (Ma et al., 2018). The GTPase defective mutant form of Arfrp1, Arfrp1 (Q79L), can inhibit the packaging of Vangl2 in vesicles in a concentration dependent manner (Ma et al., 2018).
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版权信息
© 2020 The Authors; exclusive licensee Bio-protocol LLC.
如何引用
Readers should cite both the Bio-protocol article and the original research article where this protocol was used:
分类
分子生物学 > 蛋白质 > 检测
生物化学 > 蛋白质 > 翻译后修饰
细胞生物学 > 细胞器分离 > 高尔基体
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