发布: 2017年07月20日第7卷第14期 DOI: 10.21769/BioProtoc.2416 浏览次数: 7414
评审: Peichuan ZhangAnonymous reviewer(s)
Abstract
Post-translational protein modifications (PTMs) orchestrate the activity of individual proteins and ensure their proper function. While modifications such as phosphorylation or glycosylation are well understood, more unusual modifications, including nitrosylation or AMPylation remain comparatively poorly characterized. Research on protein AMPylation–which refers to the covalent addition of an AMP moiety to the side chains of serine, threonine or tyrosine–has undergone a renaissance (Yarbrough et al., 2009; Engel et al., 2012; Ham et al., 2014; Woolery et al., 2014; Preissler et al., 2015; Sanyal et al., 2015; Truttmann et al., 2016; Truttmann et al., 2017). The identification and characterization of filamentation (fic) domain-containing AMPylases sparked new interest in this PTM (Kinch et al., 2009; Yarbrough et al., 2009). Based on recent in vivo and in vitro studies, we now know that secreted bacterial AMPylases covalently attach AMP to members of the Rho family of GTPases, while metazoan AMPylases modify HSP70 family proteins in the cytoplasm and the endoplasmic reticulum (ER) (Itzen et al., 2011; Hedberg and Itzen, 2015; Truttmann and Ploegh, 2017). AMPylation is thought to trap HSP70 in a primed yet transiently disabled state that cannot participate in protein refolding reactions (Preissler et al., 2015). In vitro AMPylation experiments are key to assess the activity, kinetics and specificity of protein AMPylation catalyzed by pro- and eukaryotic enzymes. These simple assays require recombinant AMPylases, target proteins (Rho GTPases, HSP70s), as well as ATP as a nucleotide source. Here, we describe strategies to qualitatively and quantitatively study protein AMPylation in vitro.
Keywords: AMPylation (AMP化)Background
Metazoan cell signaling is complex and requires tight control. Aberrations in this well-balanced system threaten cellular homeostasis and induce several maintenance systems aimed at restoring the balance (Kim et al., 2013). Protein AMPylation is directly linked to cellular stress: AMPylation of Rho GTPases by bacterial toxins rewires GTPase-dependent signaling, eventually leading to a collapse of the actin cytoskeleton and cell death (Yarbrough et al., 2009; Mattoo et al., 2011). In contrast, AMPylation of Grp78/BiP in the ER keeps this chaperone in a primed, yet silent conformation to be awoken and set in motion once the burden of unfolded protein in the ER surpasses a certain threshold (Preissler et al., 2015; Sanyal et al., 2015). We and others have extensively used in vitro AMPylation assays to study general properties, target selectivity as well as reaction kinetics of Fic domain-containing AMPylases. We used a combination of distinct in vitro AMPylation assays to i) identify novel targets in complex cell lysates, ii) validate suspected targets and iii) approach the role of AMPylase dimerization and auto-modification as prerequisites for enzymatic activity (Truttmann et al., 2015; 2016 and 2017). Our efforts aim at understanding the scope and impact of the AMPylome on cellular signaling. The in vitro AMPylation assays described herein present methods to achieve this goal.
Materials and Reagents
Equipment
Software
Procedure
文章信息
版权信息
© 2017 The Authors; exclusive licensee Bio-protocol LLC.
如何引用
Truttmann, M. C. and Ploegh, H. L. (2017). In vitro AMPylation Assays Using Purified, Recombinant Proteins. Bio-protocol 7(14): e2416. DOI: 10.21769/BioProtoc.2416.
分类
生物化学 > 蛋白质 > 修饰
您对这篇实验方法有问题吗?
在此处发布您的问题,我们将邀请本文作者来回答。同时,我们会将您的问题发布到Bio-protocol Exchange,以便寻求社区成员的帮助。
提问指南
+ 问题描述
写下详细的问题描述,包括所有有助于他人回答您问题的信息(例如实验过程、条件和相关图像等)。
Share
Bluesky
X
Copy link