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. 형질 <ol><li> 100 mm 배양 판 (2 × 106 세포 / 접시)에 HEK293 세포 종자. 배양 10 % 소 태아 혈청, 100 μg의 / ㎖ 스트렙토 마이신, 100 유닛 / ㎖의 페니실린으로 보충 된 둘 베코 변형 이글 배지에서 세포. 5 % CO 2 및 37 ℃로 가습 된 배양기에서 세포를 인큐베이션. </li><li> 다음 날, FLAG-태그 ARIP4 플라스미드의 10 μg의 제조업체의 방향 (11)에 따라 형질 전환 시약의 40 μl를 이용하여 세포를 형질. </li></ol> 2. 단백질 추출 <ol><li> 약 트랜 스펙 션 후 36 시간이 빙냉 PBS로 세포를 세척하고 스크레이퍼를 사용하여 세포를 수확. 1.5 mltube에 세포를 전송하고 4 ℃에서 2 분 동안 8,000 XG에 그것을 원심 분리기. 대기음 뜨는 배에서 세포 펠렛을 재현 탁 0.4 M KCl을 버퍼의 펠릿 볼륨 (높은 염 완충액 : 20 mM 트리스 -HCl (pH 8.0), 0.4 M KCl을5 밀리미터의 MgCl 2, 10 % 글리세롤, 0.1 % NP-40, 10 밀리미터 B-mercaptethanol, 1X 프로테아제 억제제 칵테일). 4 ℃에서 20 분 동안 혼합물을 돌립니다. </li><li> 4 ℃에서 10 분 동안 17,700 XG에서 튜브를 원심 분리기. </li><li> (새로운 2 ㎖의 튜브에 상청 (전체 세포 추출물)을 전송하고 0 M KCl을 버퍼의 초기 부피 3 배 추가 희석 완충액 : 20 mM 트리스 -HCl (pH 8.0), 5 밀리미터의 MgCl 2, 10 % 글리세롤, 0.1 % NP-40, 10 밀리미터 β 머 캅토 에탄올, 1X 프로테아제 억제제 칵테일). </li><li> 다른 원심 분리 (4 ℃에서 10 분 동안 17,700 XG)을 수행하고, 새로운 2 ML 튜브에 뜨는 (전체 세포 추출물)를 전송합니다. </li></ol> 3. 면역 침전 <ol><li> 20 mM의 트리스 : 원심 분리 (2.4) 중, (0.1M KCl을 완충액으로 두번 저염 완충액을 세척 한 다음 PBS로 안티 FLAG 비드 50 ㎕의 0.1 M 글리신 - 염산하고 1 M 트리스 - 히드로 클로라이드를 씻어 염산 (PH 8.0), 0.1 M의 KCl, 5 mM의 MgCl2를, 10 % 글리세롤, 0.1 % NP-40, 10mM (B) 머 캅토 에탄올, 1X 프로테아제 억제제 칵테일). 이 세척 공정의 원심 분리는 39 ° C에서 1 분 동안 2,000 × g으로 수행된다. </li><li> 전체 세포 추출물 FLAG 비드의 50 μL를 혼합하고 가볍게 2-4 ℃로한다 (단계 2.4의 전체 세포 추출물의 1 %는 또한 나중에 사용하기 위해 -80 ℃에서 보관한다에서 4 시간 동안 혼합물을 회전 ) 입력으로. </li><li> 마이크로 스핀 열 (중력 드롭)에 샘플을 전송합니다. (입력 및 관류 웨스턴 블롯 분석을 이용하여 양자의 단백질 수준을 확인), 1.5 ㎖의 튜브에 관류 유지 액체 질소를 사용하여 동결하고, -80 ℃에서 보관. </li><li> 국기 비즈 (중력 드롭)을 씻어 0.1 M KCl을 버퍼 (낮은 소금 버퍼)의 1 ML을 추가합니다. </li><li> 3.4 적어도 네 번 이상 (오 세척의 총) 단계를 반복합니다. </li></ol> 4. 용출 <ol><li> 1.5 ML 튜브에 열을 놓고 1 분 동안 2,000 XG에이를 원심 분리; 구슬 건조됩니다. </li><li> 하단 캡열. </li><li> 0.1 M 글리신 - 염산 (PH 2.5)의 (FLAG 구슬의 부피와 동일) 50 μl를 추가합니다. </li><li> 부드럽게 실온에서 10 분 동안 혼합물을 흔들어. </li><li> 새로운 1.5 ML 튜브에 열을 놓고 1 분 동안 2,000 XG에 그것을 원심 분리기. </li><li> 용출액을 1 M Tris-HCl (pH8.0)을 10 ㎕의 중화; 피펫 또는 와류 장치를 이용하여 잘 혼합한다. </li></ol> 5. 알킬화 및 트립신 <ol><li> 100 mM의 NH 4 HCO 3, CH 3 CN 10 μL, 혼합물에 디티 오 트레이 톨의 2 μL (112 μl의 총 부피)의 50 μl를 추가합니다. </li><li> 56 ° C에서 30 분 동안 샘플을 인큐베이션. </li><li> 실온에서 10 분 동안 샘플을 놓는다. </li><li> 요오도 아세트 아미드 시료에 333 mm의 10 μl를 첨가하고 37 ℃에서 30 분 동안 어두운 데에서 부화. </li><li> 혼합물에 트립신의 10 μL (33 NG / μL)을 추가하고 37 ° C에서 하룻밤을 품어. </li></ol><ol><li> 밤새 트립신 처리 후, LC-MS / MS 시설이나 분석 12 타사 질량 분석 실험실로 최종 제품을 수송. </li></ol>

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The authors have nothing to disclose.

효율적인 형질 감염 프로토콜이 성공적인 결과를 얻는 것이 필수적이다. 따라서, 우리는 면역 FLAG 태그가 단백질 수준을 결정하는 웨스턴 블롯 분석을 사용하는 것이 좋습니다. 이 단계는 IP가 성공적으로 수행되었는지, 그들의 관심 단백질이 제대로 또한, 과발현되어 있는지 확인하려면 사용자 수 있습니다. FLAG 태그가 단백질 수준은 질량 분광 분석에 앞서 확인하여야한다. ...

단백질 - 단백질 상호 작용은 다양한 생물학적 기능에 중요한 역할을한다. 따라서, 이러한 상호 작용은 신호 전달에 연루되어왔다 세포막 단백질 수송; 세포의 신진 대사; 및 DNA 복제, DNA 손상 복구, 재조합 및 전사 1, 2, 3, 4 등 여러 핵 프로세스. 이러한 상호 작용에 관여하는 단백질을 확인하는 것은이 세포 과정에 대한 우리의 이해를 증진하는 것이 중요하다. 면역 침전 (IP)는 단백질 - 단백질 상호 작용을 분석하는데 사용되는 검증 된 기술이다. 공동 - 면역 침전 된 단백질의 동정을 용이하게하기 위하여, 질량 분석계는 종종 이용 5, 6, 7, 8,9. 항체와 단백질 복합체의 공지 부재 타겟팅함으로써, 단백질 복합체를 분리하고,이어서 질량 분광 분석을 통해 그 미지의 컴포넌트를 식별 할 수있다. ARIP4 (안드로겐 수용체 상호 작용하는 단백질 4), 전사 coregulator은 활성화 또는 상황에 의존적으로 9, 10 년 대상 발기인을 억제하기 위해 핵 수용체 단백질과 상호 작용한다. 더 이러한 핵 인자를 지배하는 전사 조절 메커니즘을 이해하기 위해 정화하고, LC-MS / MS 시스템을 사용하여 ARIP4 상호 작용 단백질을 확인하는 포괄적 인 방법을 설명한다.

<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.

우리는 강한 신호 ARIP4 약 160 KDa의뿐 모의 샘플 제어 및 몇몇 다른 미지의 단백질의 것과 (도 1)을 확인 하였다. LC-MS / MS 분석은 펩티드 복합체 ARIP4 FLAG 비드 (표 1)의 분획 내의 잠재적 인 펩티드 공동 인자를 모두 식별. P62 (Sequestosome1)는 공지 ARIP4 공동 인자 (11)는이 시스템 (11)의 유효성을 확인하는 분석 (표...

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

우리는 LC-MS / MS 시스템을 사용 coregulatory 상호 작용 단백질의 정제 방법을 확립 하였다.

LC-MS / MS 분석을 이용하여 핵 공동 인자와 상호 작용 단백질의 높은 처리량 식별 단백질 제조 방법

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

Universidad San Sebastian

Research

JoVE Journal

Biochemistry

8.2K 조회수.  Osaka University.  우리는 LC-MS / MS 시스템을 사용 coregulatory 상호 작용 단백질의 정제 방법을 확립 하였다. 

비디오: 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.

블루 기본 페이지와 단백질 상관 관계 프로파일 링에 의한 선호도 정제 단백질 복합체 해결

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

연구

생화학

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.

질량 분석 기반 식별 RNA 바인딩 영역에 대 한 샘플 준비

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.

복잡 한 자연 유기 물질 혼합물을 특성화에 대 한 단일 처리량 보완 고해상도 분석 기법

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

환경과학

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.

BN-MS 분석에 의한 고분해능 컴플렉스 프로파일링

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.

대규모 핵 상호 작용 프로파일링을 위한 라벨 없는 면역 침전 질량 분광 워크플로우

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.

을 바탕으로 단백질 - 단백질 상호 작용의 확인에 프로토콜<sup&gt; 15</sup&gt; N 신진 대사 라벨링, Immunoprecipitation, 수량 질량 분석법 및 선호도 변조

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

생물학

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.

단백질-단백질 상호 작용 네트워크의 질라 식별을 위한 터보ID 기반 근접 라벨링

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

면역학 및 감염병학

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.

종합 달팽이 프로테옴을 확인하는 상향식 (bottom-up)과 샷건 단백질 체학 (Proteomics)

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.

SILAC - 면역 정량 프로테오믹스를 사용하여 포유 동물 세포에있는 단백질 상호 작용 파트너의 식별

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.

뉴런 리소좀 상호작용과 근접 라벨링 단백질체학의 특성 분석

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