Name: a protein preparation method for the high-throughput identification of proteins interacting with a nuclear cofactor using lc-ms/ms analysis
Uploaded: 2017-01-24T12:30:00.000+00:00
Duration: 5 min 43 s
Description: Watch this Scientific Journal Video about A Protein Preparation Method for the High-throughput Identification of Proteins Interacting with a Nuclear Cofactor Using LC-MS/MS Analysis at JoVE.com

This study was supported by the Astellas Foundation for Research on Metabolic Disorders (HT), the Takeda Science Foundation (HT), and by a Japan Society for the Promotion of Science Grants-in-Aid for Young Scientists (B) to HT.

1.转<ol><li>种子在100毫米培养皿（2×10 6个细胞/皿）HEK293细胞。培养在补充有10％胎牛血清，100μg/ ml的链霉素和100单位/ ml青霉素的细胞在Dulbecco改进的Eagle氏培养基。孵育在加湿培养箱将细胞在5％CO 2和37℃。 </li><li>第二天，转染细胞10微克FLAG标记ARIP4质粒按照制造商的指示11，用40微升转染试剂用。 </li></ol> 2.蛋白提取<ol><li>约36小时转染后，立即用冰冷的PBS将细胞并使用刮刀收获细胞。转移细胞到1.5 mltube并在4℃下以8000 xg离心离心它为2分钟。吸出上清，重悬细胞沉淀在5×0.4米氯化钾缓冲的沉淀量（高盐缓冲液:20毫摩尔的Tris-HCl（pH为8.0），0.4M氯化钾，5mM的MgCl 2的，10％甘油，0.1％NP-40，10毫B-巯基乙醇，1×蛋白酶抑制剂鸡尾酒）。旋转该混合物在4℃下20分钟。 </li><li>离心管中，在17700 XG在4℃下10分钟。 </li><li>上清液（全细胞提取物）转移到新的2毫升管中，并添加3×0米氯化钾缓冲的初始体积（稀释缓冲液:20毫摩尔的Tris-HCl（pH值8.0），5mM的MgCl 2的，10％甘油， 0.1％的NP-40，10毫β巯基乙醇，1×蛋白酶抑制剂鸡尾酒）。 </li><li>执行另一个离心（17700×g离心4℃10分钟），上清液（全细胞提取物）转移到新的2ml管中。 </li></ol> 3.免疫沉淀<ol><li>在离心（2.4），洗50微升用PBS抗FLAG珠，0.1M甘氨酸 - 盐酸盐，然后的1M Tris盐酸，然后洗涤两次，用0.1M氯化钾缓冲液（低盐缓冲液:20毫摩尔三 - 盐酸（pH值8.0），0.1M氯化钾，5mM的氯化镁，10％甘油，0.1％NP-40，10μMM B巯基乙醇，1×蛋白酶抑制剂鸡尾酒）。此洗涤过程中离心分离是在2000 xg离心在4℃下进行1分钟。 </li><li>混合50微升FLAG珠与全细胞提取物，并在2-4℃（从步骤2.4全细胞提取物的1％也应保持在-80℃以供将来使用轻轻旋转混合物4小时为输入）。 </li><li>样品转移到微离心柱（重力下降）。保持流通在1.5ml管中，利用液氮冷冻，然后将其存储在-80℃下（检查输入和用Western印迹分析的流通的蛋白水平）。 </li><li>加入1 ml 0.1米氯化钾缓冲液（低盐缓冲液）的洗FLAG珠（重力下降）。 </li><li>重复步骤3.4至少四次（对总共五个洗涤）。 </li></ol> 4.洗脱<ol><li>放置柱到1.5毫升管，并在2000 xg离心离心它为1分钟;珠会干。 </li><li>盖的底列。 </li><li>添加50微升（等于FLAG珠的体积）0.1M甘氨酸 - 盐酸（pH值2.5）的。 </li><li>轻轻晃动，在室温下10分钟的混合物。 </li><li>放置柱到一个新的1.5毫升管，并在2000 xg离心离心它为1分钟。 </li><li>洗脱溶液与10微升的1M的Tris-HCl（pH 8.0）中的中和;通过移液或者通过使用涡旋机拌匀。 </li></ol> 5.烷基化和胰蛋白酶消化<ol><li>添加100mM的NH 4 HCO 3，10微升CH 3 CN的，和2μl的二硫苏糖醇的混合物（112微升总体积）的50微升。 </li><li>在56℃孵育样品30分钟。 </li><li>放置在室温下的样品10分钟。 </li><li>添加10微升333毫摩尔的碘乙酰胺的样品，并在37°C孵育它在黑暗中30分钟。 </li><li>添加胰蛋白酶的10微升（33纳克/微升）到混合物中，并在37℃过夜孵育它。 </li></ol><ol><li>以下过夜胰蛋白酶，运到最终产品的LC-MS / MS设施或用于分析12第三方质谱实验室。 </li></ol>

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The authors have nothing to disclose.

有效转染是必不可少的获得与该协议的成功的结果。因此，我们建议您使用Western blot分析，以确定免疫沉淀的FLAG标签的蛋白质水平。这个步骤允许用户以验证他们感兴趣的蛋白被正确过度表达，此外，该IP被成功执行。 FLAG标签的蛋白质水平也应之前的质谱分析进行检查。 有模拟样本应该被用作阴性对照，以避免得到假阳性结果，并以鉴别从真相互作用的背景。此外，研究人...

蛋白质 - 蛋白质相互作用发挥多种生物学功能中起重要作用。正因为如此，这些相互作用已牵涉信号转导;跨细胞膜蛋白质运输;细胞的新陈代谢;和几个核过程，包括DNA复制，DNA损伤修复，重组和转录1，2，3，4。查明参与这些相互作用蛋白质因此，推进我们的这些细胞过程的理解是至关重要的。 免疫沉淀（IP）是用于分析蛋白质 - 蛋白质相互作用经过验证的技术。为了便于共同免疫沉淀的蛋白的鉴定，质谱常常利用5，6，7，8，9。通过用抗体靶向的蛋白复合物的公知的部件，它是可以分离的蛋白复合物，并随后经由质谱分析确定其未知组分。 ARIP4（雄激素受体相互作用蛋白4），一个转录coregulator，核受体蛋白以激活或在一个依赖于上下文的方式9,10抑制其靶启动子相互作用。为了更好地了解控制这些核因子的转录调控机制，我们描述了一个全面的方法来净化和使用LC-MS / MS系统识别ARIP4相互作用的蛋白质。

<table><tbody><tr><td>Lipofectamine 2000 Transfection Reagent</td><td>Thermo Fisher Scientific</td><td>11668019</td><td></td></tr><tr><td>Protease Inhibitor Cocktail (EDTA free) (100x)</td><td>nacalai tesque</td><td>03969-21</td><td></td></tr><tr><td>ANTI-FLAG M2 Affinity Gel</td><td>Sigma-Aldrich</td><td>A2220</td><td></td></tr><tr><td>Micro Bio-Spin Columns</td><td>BIO-RAD</td><td>732-6204</td><td></td></tr></tbody></table>

a protein preparation method for the high-throughput identification of proteins interacting with a nuclear cofactor using lc-ms/ms analysis

Transcriptional coregulators are vital to the efficient transcriptional regulation of nuclear chromatin structure. Coregulators play a variety of roles in regulating transcription. These include the direct interaction with transcription factors, the covalent modification of histones and other proteins, and the occasional chromatin conformation alteration. Accordingly, establishing relatively quick methods for identifying proteins that interact within this network is crucial to enhancing our understanding of the underlying regulatory mechanisms. LC-MS/MS-mediated protein binding partner identification is a validated technique used to analyze protein-protein interactions. By immunoprecipitating a previously-identified member of a protein complex with an antibody (occasionally with an antibody for a tagged protein), it is possible to identify its unknown protein interactions via mass spectrometry analysis. Here, we present a method of protein preparation for the LC-MS/MS-mediated high-throughput identification of protein interactions involving nuclear cofactors and their binding partners. This method allows for a better understanding of the transcriptional regulatory mechanisms of the targeted nuclear factors.

我们确定了一个强烈的信号ARIP4，约160千道尔顿，以及那些一个模拟采样控制等几个未知的蛋白质（ 图1）。 LC-MS / MS分析，鉴定两ARIP4复杂肽和FLAG珠（ 表1）的级分中的潜在的肽辅因子。 P62（Sequestosome1），公知的辅因子ARIP4 11中的分析（ 表1），这证实了本系统11的功效被确定。我们还确定了与ARIP4?...

Watch this Scientific Journal Video about A Protein Preparation Method for the High-throughput Identification of Proteins Interacting with a Nuclear Cofactor Using LC-MS/MS Analysis at JoVE.com

A Protein Preparation Method for the High-throughput Identification of Proteins Interacting with a Nuclear Cofactor Using LC-MS/MS Analysis

我们已经建立了使用LC-MS / MS系统共同调节相互作用蛋白的纯化的方法。

A蛋白制备方法在蛋白质与核余子交互使用LC-MS / MS分析的高通量鉴定

Transcriptional coregulators are vital to the efficient transcriptional regulation of nuclear chromatin structure. Coregulators play a variety of roles in ...

a-protein-preparation-method-for-high-throughput-identification

Research

JoVE Journal

Biochemistry

8.3K 次观看.  Osaka University. 我们已经建立了使用LC-MS / MS系统共同调节相互作用蛋白的纯化的方法。 

视频: A Protein Preparation Method for the High-throughput Identification of Proteins Interacting with a Nuclear Cofactor Using LC-MS/MS Analysis

Resolving Affinity Purified Protein Complexes by Blue Native PAGE and Protein Correlation Profiling

Most proteins act in association with others; hence, it is crucial to characterize these functional units in order to fully understand biological processes. Affinity purification coupled to mass spectrometry (AP-MS) has become the method of choice for identifying protein-protein interactions. However, conventional AP-MS studies provide information on protein interactions, but the organizational information is lost. To address this issue, we developed a strategy to unravel the distinct functional assemblies a protein might be involved in, by resolving affinity-purified protein complexes prior to their characterization by mass spectrometry. Protein complexes isolated through affinity purification of a bait protein using an epitope tag and competitive elution are separated through blue native electrophoresis. Comparison of protein migration profiles through correlation profiling using quantitative mass spectrometry allows assignment of interacting proteins to distinct molecular entities. This method is able to resolve protein complexes of close molecular weights that might not be resolved by traditional chromatographic techniques such as gel filtration. With little more work than conventional AP-geLC-MS/MS, we demonstrate this strategy may in many cases be adequate for obtaining protein complex topological information concomitantly to identifying protein interactions.

Here we present protocols for affinity purification of protein complexes and their separation by blue native PAGE, followed by protein correlation profiling using label free quantitative mass spectrometry. This method is useful to resolve interactomes into distinct protein complexes.

解决由蓝变性PAGE和蛋白质相关剖析亲和纯化的蛋白复合物

Most proteins act in association with others; hence, it is crucial to characterize these functional units in order to fully understand biological ...

科研

生物化学

Sample Preparation for Mass Spectrometry-based Identification of RNA-binding Regions

Noncoding RNAs play important roles in several nuclear processes, including regulating gene expression, chromatin structure, and DNA repair. In most cases, the action of noncoding RNAs is mediated by proteins whose functions are in turn regulated by these interactions with noncoding RNAs. Consistent with this, a growing number of proteins involved in nuclear functions have been reported to bind RNA and in a few cases the RNA-binding regions of these proteins have been mapped, often through laborious, candidate-based methods.
Here, we report a detailed protocol to perform a high-throughput, proteome-wide unbiased identification of RNA-binding proteins and their RNA-binding regions. The methodology relies on the incorporation of a photoreactive uridine analog in the cellular RNA, followed by UV-mediated protein-RNA crosslinking, and mass spectrometry analyses to reveal RNA-crosslinked peptides within the proteome. Although we describe the procedure for mouse embryonic stem cells, the protocol should be easily adapted to a variety of cultured cells.

We describe a protocol to identify RNA-binding proteins and map their RNA-binding regions in live cells using UV-mediated photocrosslinking and mass spectrometry.

RNA 结合区质量谱鉴定的样品制备

Noncoding RNAs play important roles in several nuclear processes, including regulating gene expression, chromatin structure, and DNA repair. In most ...

Single-throughput Complementary High-resolution Analytical Techniques for Characterizing Complex Natural Organic Matter Mixtures

Natural organic matter (NOM) is composed of a highly complex mixture of thousands of organic compounds which, historically, proved difficult to characterize. However, to understand the thermodynamic and kinetic controls on greenhouse gas (carbon dioxide [CO2] and methane [CH4]) production resulting from the decomposition of NOM, a molecular-level characterization coupled with microbial proteome analyses is necessary. Further, climate and environmental changes are expected to perturb natural ecosystems, potentially upsetting complex interactions that influence both the supply of organic matter substrates and the microorganisms performing the transformations. A detailed molecular characterization of the organic matter, microbial proteomics, and the pathways and transformations by which organic matter is decomposed will be necessary to predict the direction and magnitude of the effects of environmental changes. This article describes a methodological throughput for comprehensive metabolite characterization in a single sample by direct injection Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS), gas chromatography mass spectrometry (GC-MS), nuclear magnetic resonance (NMR) spectroscopy, liquid chromatography mass spectrometry (LC-MS), and proteomics analysis. This approach results in a fully-paired dataset which improves statistical confidence for inferring pathways of organic matter decomposition, the resulting CO2 and CH4 production rates, and their responses to environmental perturbation. Herein we present results of applying this method to NOM samples collected from peatlands; however, the protocol is applicable to any NOM sample (e.g., peat, forested soils, marine sediments, etc.).

This protocol describes a single throughput for complementary analytical and omics techniques culminating in a fully-paired characterization of natural organic matter and microbial proteomics in different ecosystems. This approach permits robust comparisons for identifying metabolic pathways and transformations important for describing greenhouse gas production and predicting responses to environmental change.

用于表征复杂天然有机物混合物的单吞吐量互补高分辨率分析技术

Natural organic matter (NOM) is composed of a highly complex mixture of thousands of organic compounds which, historically, proved difficult to ...

环境科学

High-Resolution Complexome Profiling by Cryoslicing BN-MS Analysis

Proteins generally exert biological functions through interactions with other proteins, either in dynamic protein assemblies or as a part of stably formed complexes. The latter can be elegantly resolved according to molecular size using native polyacrylamide gel electrophoresis (BN-PAGE). Coupling of such separations to sensitive mass spectrometry (BN-MS) has been well-established and theoretically allows for exhaustive assessment of the extractable complexome in biological samples. However, this approach is rather laborious and provides limited complex size resolution and sensitivity. Also, its application has remained restricted to abundant mitochondrial and plastid proteins. Thus, for a majority of proteins, information regarding integration into stable protein complexes is still lacking. Presented here is an optimized approach for complexome profiling comprising preparative-scale BN-PAGE separation, sub-millimeter sampling of broad gel lanes by cryomicrotome slicing, and mass spectrometric analysis with label-free protein quantification. The procedures and tools for critical steps are described in detail. As an application, the report describes complexome analysis of a solubilized endosome-enriched membrane fraction from mouse kidneys, with 2,545 proteins profiled in total. The results demonstrate identification of uniform, low-abundance membrane proteins such as intracellular ion channels as well as high resolution, complex protein assembly patterns, including glycosylation isoforms. The results are in agreement with independent biochemical analyses. In summary, this methodology allows for comprehensive and unbiased identification of protein (super)complexes and their subunit composition, providing a basis for investigating stoichiometry, assembly, and interaction dynamics of protein complexes in any biological system.

A versatile cryoslicing BN-MS protocol using a microtome is presented for high-resolution complexome profiling.

通过低温BN-MS分析进行高分辨率复杂分析

Proteins generally exert biological functions through interactions with other proteins, either in dynamic protein assemblies or as a part of stably formed ...

Label-Free Immunoprecipitation Mass Spectrometry Workflow for Large-scale Nuclear Interactome Profiling

Immunoaffinity purification mass spectrometry (IP-MS) has emerged as a robust quantitative method of identifying protein-protein interactions. This publication presents a complete interaction proteomics workflow designed for identifying low abundance protein-protein interactions from the nucleus that could also be applied to other subcellular compartments. This workflow includes subcellular fractionation, immunoprecipitation, sample preparation, offline cleanup, single-shot label-free mass spectrometry, and downstream computational analysis and data visualization. Our protocol is optimized for detecting compartmentalized, low abundance interactions that are difficult to identify from whole cell lysates (e.g., transcription factor interactions in the nucleus) by immunoprecipitation of endogenous proteins from fractionated subcellular compartments. The sample preparation pipeline outlined here provides detailed instructions for the preparation of HeLa cell nuclear extract, immunoaffinity purification of endogenous bait protein, and quantitative mass spectrometry analysis. We also discuss methodological considerations for performing large-scale immunoprecipitation in mass spectrometry-based interaction profiling experiments and provide guidelines for evaluating data quality to distinguish true positive protein interactions from nonspecific interactions. This approach is demonstrated here by investigating the nuclear interactome of the CMGC kinase, DYRK1A, a low abundance protein kinase with poorly defined interactions within the nucleus.

Described is a proteomics workflow for identifying protein interaction partners from a nuclear subcellular fraction using immunoaffinity enrichment of a given protein of interest and label-free mass spectrometry. The workflow includes subcellular fractionation, immunoprecipitation, filter aided sample preparation, offline cleanup, mass spectrometry, and a downstream bioinformatics pipeline.

用于大规模核相互作用分析的无标签免疫沉淀质谱工作流程

Immunoaffinity purification mass spectrometry (IP-MS) has emerged as a robust quantitative method of identifying protein-protein interactions. This ...

A Protocol for the Identification of Protein-protein Interactions Based on 15N Metabolic Labeling, Immunoprecipitation, Quantitative Mass Spectrometry and Affinity Modulation

Protein-protein interactions are fundamental for many biological processes in the cell. Therefore, their characterization plays an important role in current research and a plethora of methods for their investigation is available1. Protein-protein interactions often are highly dynamic and may depend on subcellular localization, post-translational modifications and the local protein environment2. Therefore, they should be investigated in their natural environment, for which co-immunoprecipitation approaches are the method of choice3. Co-precipitated interaction partners are identified either by immunoblotting in a targeted approach, or by mass spectrometry (LC-MS/MS) in an untargeted way. The latter strategy often is adversely affected by a large number of false positive discoveries, mainly derived from the high sensitivity of modern mass spectrometers that confidently detect traces of unspecifically precipitating proteins. A recent approach to overcome this problem is based on the idea that reduced amounts of specific interaction partners will co-precipitate with a given target protein whose cellular concentration is reduced by RNAi, while the amounts of unspecifically precipitating proteins should be unaffected. This approach, termed QUICK for QUantitative Immunoprecipitation Combined with Knockdown4, employs Stable Isotope Labeling of Amino acids in Cell culture (SILAC)5 and MS to quantify the amounts of proteins immunoprecipitated from wild-type and knock-down strains. Proteins found in a 1:1 ratio can be considered as contaminants, those enriched in precipitates from the wild type as specific interaction partners of the target protein. Although innovative, QUICK bears some limitations: first, SILAC is cost-intensive and limited to organisms that ideally are auxotrophic for arginine and/or lysine. Moreover, when heavy arginine is fed, arginine-to-proline interconversion results in additional mass shifts for each proline in a peptide and slightly dilutes heavy with light arginine, which makes quantification more tedious and less accurate5,6. Second, QUICK requires that antibodies are titrated such that they do not become saturated with target protein in extracts from knock-down mutants.
Here we introduce a modified QUICK protocol which overcomes the abovementioned limitations of QUICK by replacing SILAC for 15N metabolic labeling and by replacing RNAi-mediated knock-down for affinity modulation of protein-protein interactions. We demonstrate the applicability of this protocol using the unicellular green alga Chlamydomonas reinhardtii as model organism and the chloroplast HSP70B chaperone as target protein7 (Figure 1). HSP70s are known to interact with specific co-chaperones and substrates only in the ADP state8. We exploit this property as a means to verify the specific interaction of HSP70B with its nucleotide exchange factor CGE19.

A Protocol for the Identification of Protein-protein Interactions Based on 15N Metabolic Labeling, Immunoprecipitation, Quantitative Mass Spectrometry and Affinity Modulation

We present a variation of the QUICK (QUantitative Immunoprecipitation Combined with Knockdown) approach that was introduced previously to distinguish between true and false protein-protein interactions. Our approach is based on 15N metabolic labeling, the modulation of affinities of protein-protein interactions by the presence/absence of ATP, immunoprecipitation, and quantitative mass spectrometry.

一个协议，用于基于蛋白质 - 蛋白质相互作用的鉴定<sup&gt; 15</sup&gt; N代谢标记，免疫沉淀法，的定量质谱法和亲和调制

Protein-protein interactions are fundamental for many biological processes in the cell. Therefore, their characterization plays an important role in ...

生物学

TurboID-Based Proximity Labeling for In Planta Identification of Protein-Protein Interaction Networks

Proximity labeling (PL) techniques using engineered ascorbate peroxidase (APEX) or Escherichia coli biotin ligase BirA (known as BioID) have been successfully used for identification of protein-protein interactions (PPIs) in mammalian cells. However, requirements of toxic hydrogen peroxide (H2O2) in APEX-based PL, longer incubation time with biotin (16&#8211;24 h), and higher incubation temperature (37 &#176;C) in BioID-based PL severely limit their applications in plants. The recently described TurboID-based PL addresses many limitations of BioID and APEX. TurboID allows rapid proximity labeling of proteins in just 10&#8201;min under room temperature (RT) conditions. Although the utility of TurboID has been demonstrated in animal models, we recently showed that TurboID-based PL performs better in plants compared to BioID for labeling of proteins that are proximal to a protein of interest. Provided here is a step-by-step protocol for the identification of protein interaction partners using the N-terminal Toll/interleukin-1 receptor (TIR) domain of the nucleotide-binding leucine-rich repeat (NLR) protein family as a model. The method describes vector construction, agroinfiltration of protein expression constructs, biotin treatment, protein extraction and desalting, quantification, and enrichment of the biotinylated proteins by affinity purification. The protocol described here can be easily adapted to study other proteins of interest in Nicotiana and other plant species.

Described here is a proximity labeling method for identification of interaction partners of the TIR domain of the NLR immune receptor in Nicotiana benthamiana leaf tissue. Also provided is a detailed protocol for the identification of interactions between other proteins of interest using this technique in Nicotiana and other plant species.

基于 TurboID 的接近标签，用于蛋白质-蛋白质相互作用网络的植物中识别

Proximity labeling (PL) techniques using engineered ascorbate peroxidase (APEX) or Escherichia coli biotin ligase BirA (known as BioID) have been ...

免疫与感染

Bottom-up and Shotgun Proteomics to Identify a Comprehensive Cochlear Proteome

Proteomics is a commonly used approach that can provide insights into complex biological systems. The cochlear sensory epithelium contains receptors that transduce the mechanical energy of sound into an electro-chemical energy processed by the peripheral and central nervous systems. Several proteomic techniques have been developed to study the cochlear inner ear, such as two-dimensional difference gel electrophoresis (2D-DIGE), antibody microarray, and mass spectrometry (MS). MS is the most comprehensive and versatile tool in proteomics and in conjunction with separation methods can provide an in-depth proteome of biological samples. Separation methods combined with MS has the ability to enrich protein samples, detect low molecular weight and hydrophobic proteins, and identify low abundant proteins by reducing the proteome dynamic range. Different digestion strategies can be applied to whole lysate or to fractionated protein lysate to enhance peptide and protein sequence coverage. Utilization of different separation techniques, including strong cation exchange (SCX), reversed-phase (RP), and gel-eluted liquid fraction entrapment electrophoresis (GELFrEE) can be applied to reduce sample complexity prior to MS analysis for protein identification.

Proteome analysis of the cochlear sensory epithelium can be challenging due to its small size and because membrane proteins are difficult to isolate and identify. Both membrane and soluble proteins can be identified by combining multiple preparative methods and separation techniques along with high-resolution mass spectrometry.

自下而上和猎枪蛋白质组学鉴定一个全面的蛋白质组耳蜗

Proteomics is a commonly used approach that can provide insights into complex biological systems. The cochlear sensory epithelium contains receptors that ...

Identification of Protein Interaction Partners in Mammalian Cells Using SILAC-immunoprecipitation Quantitative Proteomics

Quantitative proteomics combined with immuno-affinity purification, SILAC immunoprecipitation, represent a powerful means for the discovery of novel protein:protein interactions. By allowing the accurate relative quantification of protein abundance in both control and test samples, true interactions may be easily distinguished from experimental contaminants. Low affinity interactions can be preserved through the use of less-stringent buffer conditions and remain readily identifiable. This protocol discusses the labeling of tissue culture cells with stable isotope labeled amino acids, transfection and immunoprecipitation of an affinity tagged protein of interest, followed by the preparation for submission to a mass spectrometry facility. This protocol then discusses how to analyze and interpret the data returned from the mass spectrometer in order to identify cellular partners interacting with a protein of interest. As an example this technique is applied to identify proteins binding to the eukaryotic translation initiation factors: eIF4AI and eIF4AII.

SILAC immunoprecipitation experiments represent a powerful means for discovering novel protein:protein interactions. By allowing the accurate relative quantification of protein abundance in both control and test samples, true interactions may be easily distinguished from experimental contaminants, and low affinity interactions preserved through use of less-stringent buffer conditions.

的蛋白质相互作用的合作伙伴在哺乳动物细胞中使用SILAC-免疫定量蛋白质组学鉴定

Quantitative proteomics combined with immuno-affinity purification, SILAC immunoprecipitation, represent a powerful means for the discovery of novel ...

Characterization of Neuronal Lysosome Interactome with Proximity Labeling Proteomics

Lysosomes frequently communicate with a variety of biomolecules to achieve the degradation and other diverse cellular functions. Lysosomes are critical to human brain function, as neurons are postmitotic and rely heavily on the autophagy-lysosome pathway to maintain cellular homeostasis. Despite advancements in the understanding of various lysosomal functions, capturing the highly dynamic communications between lysosomes and other cellular components is technically challenging, particularly in a high-throughput fashion. Here, a detailed protocol is provided for the recently published endogenous (knock-in) lysosome proximity labeling proteomic method in human induced pluripotent stem cell (hiPSC)-derived neurons. 
Both lysosomal membrane proteins and proteins surrounding lysosomes within a 10-20 nm radius can be confidently identified and accurately quantified in live human neurons. Each step of the protocol is described in detail, i.e., hiPSC-neuron culture, proximity labeling, neuron harvest, fluorescence microscopy, biotinylated protein enrichment, protein digestion, LC-MS analysis, and data analysis. In summary, this unique endogenous lysosomal proximity labeling proteomics method provides a high-throughput and robust analytical tool to study the highly dynamic lysosomal activities in live human neurons.

A neuronal lysosome proximity labeling proteomics protocol is described here to characterize the dynamic lysosomal microenvironment in human induced pluripotent stem cell-derived neurons. Lysosomal membrane proteins and proteins that interact with lysosomes (stably or transiently) can be accurately quantified in this method with excellent intracellular spatial resolution in live human neurons.

具有邻近标记蛋白质组学的神经元溶酶体相互作用组表征

Lysosomes frequently communicate with a variety of biomolecules to achieve the degradation and other diverse cellular functions. Lysosomes are critical to ...