防衛W81XWH - 05 - 1 - 0005、W81XWH - 06 - 1から0495まで、W81XWH - 08 - 1から0029とW81XWH - 08 - 1から0356までの部

1。 GST -融合タンパク質を準備<ol><li> BamH1/EcoR1 pGEX3xベクターにサブクローニングrhotekinのRho結合ドメイン（RBD）の最初のN末端90アミノ酸を含むJM109コンピテント細菌のグリセロールストックが行われます。 高効率を確保するために、次の手順は、各実験のために実行しなければなりません。我々の経験では、新しく調製したGST - RBDは、堅牢で正確な分子量GTPase活性化アッセイの鍵となります。 </li><li> LBアンプ50mlにグリセロールストックのμL50（おおよそ、解凍しないで）追加し、振盪しながら37℃で一晩を成長させる。 </li><li> 500mLのLBアンプで1:10に希釈し、1時間拡大</li><li> 2時間のためにIPTGを0.1mMのでGST -タンパク質の産生を誘導する。 </li><li> 5000に遠心ボトルや遠心分離機、Sorval GSA3ローターに均等に配布するRPM 4℃で20分間。 </li><li>遠心ボトルにペレットを再懸濁します、溶解緩衝液10ml * *細菌溶解バッファー：20％ショ糖、10％グリセロール、50mMのトリスpH8.0、0.2mMののNa 2 S 2 O 5、2mMのMgCl 2、2mMのDTTは、新鮮なPMSF、ベンズアミド、アプロチニンおよびロイペプチンを追加。 </li><li> 2〜3分間（これは超音波処理器の種類によって異なります。私たちは、マーク6で設定されたフィッシャーソニックDismembranatorモデル500、50％のサイクルを使用する）超音波洗浄します。 </li><li>遠心分離機、ソーバルSS34、4℃で20分10,000回転℃、この時点で小アリコートを取り出すことができるとSDS - PAGEによって実行されます。ゲルはクマシーで染​​色することができますし、バンドは46 kDaの明らかなはずである。 </li><li>上清を除去し、50％glutatione -セファロース4Bスラリーの1 mLを加える。 </li><li> 4℃で30分間インキュベート° Cを回転した。溶解緩衝液で3回洗浄する。 </li><li> GST -魚のバッファを使用して50％スラリー（約1ml）にGST-RBD/glutatione-Sepharoseビーズを再懸濁します** ** GST -魚のバッファ：10％グリセロール、50mMのトリスpH7.4の、100mMのNaCl、1％NP - 4、2mMのMgCl 2、新鮮なPMSF、ベンズアミド、アプロチニンおよびロイペプチンを追加する</li></ol> 2。 GST -融合は、アッセイをプルダウン<ol><li> 5〜10 × 10 6細胞/アッセイを使用して、 </li><li>一度、氷冷PBSで細胞を洗浄、氷上にプレートを保つ（我々が氷で満たされた平らなガラス皿を使用）と0.5mLのGST -魚のバッファーで溶解する。 </li><li>氷上で5分間インキュベートする、ラバーポリスマンやフラットスクラッパーを使用して、収穫の細胞は、チューブを遠心し、4℃で20,000 rpmの5分を遠心分離して譲渡℃に</li><li>新鮮なマイクロ遠心チューブに上清を移す。合計ローを（すなわちGDP + GTP結合）を決定するために50μLを取る。 </li><li> 0.5mLのGST-RBD/glutatione-Sepharoseビーズを追加し、4℃で回転で一晩℃で、インキュベートする。 </li><li> GST -魚のバッファ付き6X洗います。 </li><li> 40μL2X - Laemelliサンプルバッファーで再懸濁し、ビーズ この時点で2.4にかかった合計Rhoタンパク質のアリコートの濃度を測定し、30μgのは、対応するアクティベーションサンプルでゲル上で実行されるようにしておく必要があります。 </li><li>沸騰サンプルは90℃で5分間、軽く遠心し、上清（すなわち、ビーズを避けるために）負荷がかかると12ウェル4-20％グラジエントSDS - PAGEゲル上で実行されます。 </li><li>ないより高い150よりボルト、Towbinバッファーを用いてメンブレンにトランスファーし、100 Wの定電流で泳動する</li><li> RhoC - specfic抗体と5％ミルク/ TBST液とプローブをメンブレンにブロックする。 </li></ol> 3。代表的な結果良い結果は約22 kDaの単一バンドを生成する必要があります。悪い結果では、複数のバンドや高いバックグラウンドを生成する。これは、タンパク質分解、サンプルの不完全な洗浄または古いGST - RBDの使用を示している。 <img src="/files/ftp_upload/2083/2083fig1.jpg" alt="図1" /> 図1。RhoC GTP加水分解酵素の異なるレベルを表現する3つの別々の細胞株は、アクティブおよび総RhoCなしRhoCのアクティブと合計RhoC、高レベルの低レベルを実証するために示されている。ブロットは、取り除かれ、合計RhoCタンパク質のためのローディングコントロールとしてハウスキーピング遺伝子のアクチンに対する抗体で再プローブした。 <img src="/files/ftp_upload/2083/2083fig2.jpg" alt="図2" /> 図2。タンパク質分解、サンプルの不完全な洗浄または古いGST - RBDの使用から複数のバンドや高いバックグラウンドの結果は。

<ol>
	<li>van Golen, K. L., Wu, Z. F., Qiao, X. T., Bao, L. W., Merajver, S. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=RhoC+GTPase,+a+novel+transforming+oncogene+for+human+mammary+epithelial+cells+that+partially+recapitulates+the+inflammatory+breast+cancer+phenotype.">RhoC GTPase, a novel transforming oncogene for human mammary epithelial cells that partially recapitulates the inflammatory breast cancer phenotype.</a> Cancer Res. 60 (20), 5832-5838 (2000).</li><li>van Golen, K. L., Wu, Z. F., Qiao, X. T., Bao, L., Merajver, S. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=RhoC+GTPase+overexpression+modulates+induction+of+angiogenic+factors+in+breast+cells.">RhoC GTPase overexpression modulates induction of angiogenic factors in breast cells.</a> Neoplasia. 2 (5), 418-425 (2000).</li><li>Golen, K. L. v. a. n. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Reversion+of+RhoC+GTPase-induced+inflammatory+breast+cancer+phenotype+by+treatment+with+a+farnesyl+transferase+inhibitor.">Reversion of RhoC GTPase-induced inflammatory breast cancer phenotype by treatment with a farnesyl transferase inhibitor.</a> Mol Cancer Ther. 1 (8), 575-583 (2002).</li><li>Golen, K. L. v. a. n. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mitogen+activated+protein+kinase+pathway+is+involved+in+RhoC+GTPase+induced+motility,+invasion+and+angiogenesis+in+inflammatory+breast+cancer.">Mitogen activated protein kinase pathway is involved in RhoC GTPase induced motility, invasion and angiogenesis in inflammatory breast cancer.</a> Clin Exp Metastasis. 19 (4), 301-311 (2002).</li><li>Yao, H., Dashner, E. J., van Golen, C. M., van Golen, K. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=RhoC+GTPase+is+required+for+PC-3+prostate+cancer+cell+invasion+but+not+motility.">RhoC GTPase is required for PC-3 prostate cancer cell invasion but not motility.</a> Oncogene. 25 (16), 2285-2296 (2006).</li><li>Hall, C. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Type+I+Collagen+receptor+(alpha2beta1)+signaling+promotes+prostate+cancer+cell+invasion+through+RhoC+GTPase.">Type I Collagen receptor (alpha2beta1) signaling promotes prostate cancer cell invasion through RhoC GTPase.</a> Neoplasia. 10 (8), 797-803 (2008).</li><li>Sequeira, L., Dubyk, C. W., Riesenberger, T. A., Cooper, C. R., van Golen, K. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Rho+GTPases+in+PC-3+prostate+cancer+cell+morphology,+invasion+and+tumor+cell+diapadesis.">Rho GTPases in PC-3 prostate cancer cell morphology, invasion and tumor cell diapadesis.</a> Clin Exp Metastasis. 25, 569-579 (2008).</li><li>van Golen, K. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=CCL2+Induces+Prostate+Cancer+Transendothelial+Cell+Migration+via+Activation+of+the+Small+GTPase+Rac.">CCL2 Induces Prostate Cancer Transendothelial Cell Migration via Activation of the Small GTPase Rac.</a> J Cell Biochem. 104, 1587-1597 (2008).</li><li>Chatterjee, M., van Golen, K. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Int J Cancer. , (2010).</li><li>Sander, E. E., ten Klooster, J. P., van Delft, S., van der Kammen, R. A., Collard, J. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Rac+downregulates+Rho+activity:+reciprocal+balance+between+both+GTPases+determines+cellular+morphology+and+migratory+behavior.">Rac downregulates Rho activity: reciprocal balance between both GTPases determines cellular morphology and migratory behavior.</a> J Cell Biol. 147 (5), 1009-1022 (1999).</li></ol>

利害の衝突は宣言されません。

手順の最も重要なステップは、新鮮なGST - RBDの世代です。このステップに細心の注意を払うために失敗は失敗の主な理由です。すべてのステップは、細胞溶解液（2.5）で一晩インキュベーションにGST - RBD（1.2）の世代から、一日で行う必要があります。もう一つの重要なステップは、細胞ライセートを生成するために十分な細胞があることを一定にすることです。セル内の低いレベルで存在?...

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<td>Gluthione-sepharose 4B beads</td>
<td>&nbsp;</td>
<td>GE Healthcare</td>
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<td>Criterion 4-20% Tris-HCl gels</td>
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<td>BioRad</td>
<td>345-0032</td>
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rhoc gtpase activation assay

RhoC GTPアーゼは、RhoAのGTPアーゼ〜91％の相同性を持っています。ために細胞内での有病率から、RhoAのGTPアーゼのための多くの試薬および技術が開発されている。しかし、RhoC GTPアーゼは、比較的低レベルでの転移性癌細胞に発現している。したがって、少数のRhoC固有の試薬が開発されている。私たちはRhoC低分子量GTPaseを検出するためのRho活性化アッセイを適応している。この手法は、アクティブなRhoC GTPアーゼを引き出すためにGST - Rhoの結合ドメイン融合タンパク質を利用しています。さらに、我々は全体のレベル（GTPおよびGDP結合）RhoCのGTPアーゼを決定するアッセイの開始時に総タンパク質を収穫することができます。これは、セル内のアクティブな対総RhoC GTP加水分解酵素の測定が可能になります。この手順のいくつかの商用バージョンがしかし、市販のキットはRhoAのGTP加水分解のために最適化されており、通常はRhoC GTPアーゼのためにうまく動作しない開発されています。アッセイの部分はRhoC特異的抗体の開発だけでなく、変更されています。

Watch this Scientific Journal Video about RhoC GTPase Activation Assay at JoVE.com

RhoC GTPase Activation Assay

このプロトコルは、細胞内のアクティブなRhoC低分子量GTPaseのレベルを決定するためにプルダウンアッセイを利用しています。

RhoC GTPアーゼ活性化アッセイ

RhoC GTPase has 91% homology to RhoA GTPase.  Because of its prevalence in cells, many reagents and techniques for RhoA GTPase have been developed.  ...

Research

JoVE Journal

Biology

12.3K ビュー.  University of Delaware. このプロトコルは、細胞内のアクティブなRhoC低分子量GTPaseのレベルを決定するためにプルダウンアッセイを利用しています。

ビデオ: RhoC GTPase Activation Assay

Interview: Glycolipid Antigen Presentation by CD1d and the Therapeutic Potential of NKT cell Activation

Natural Killer T cells (NKT) are critical determinants of the immune response to cancer, regulation of autioimmune disease, clearance of infectious agents, and the development of artheriosclerotic plaques.   In this interview, Mitch Kronenberg discusses his laboratory's efforts to understand the mechanism through which NKT cells are activated by glycolipid antigens.  Central to these studies is CD1d - the antigen presenting molecule that presents glycolipids to NKT cells.  The advent of CD1d tetramer technology, a technique developed by the Kronenberg lab, is critical for the sorting and identification of subsets of specific glycolipid-reactive T cells.  Mitch explains how glycolipid agonists are being used as therapeutic agents to activate NKT cells in cancer patients and how CD1d tetramers can be used to assess the state of the NKT cell population in vivo following glycolipid agonist therapy.  Current status of ongoing clinical trials using these agonists are discussed as well as Mitch's prediction for areas in the field of immunology that will have emerging importance in the near future.

Natural Killer T cells (NKT) are critical determinants of the immune response to cancer, regulation of autioimmunity, clearance of infection, and the development of artheriosclerotic plaques. In this interview, Mitch Kronenberg discusses his laboratory's efforts to understand the mechanism through which NKT cells are activated by glycolipid antigens.

インタビュー：CD1dによる糖脂質抗原提示とNKT細胞の活性化の治療の可能性

Natural Killer T cells (NKT) are critical determinants of the immune response to cancer, regulation of autioimmune disease, clearance of infectious ...

生物学

Recordings of Neural Circuit Activation in Freely Behaving Animals

The relationship between patterns of neural activity and corresponding behavioral expression is difficult to establish in unrestrained animals. Traditional non-invasive methods require at least partially restrained research subjects, and they only allow identification of large numbers of simultaneously activated neurons. On the other hand, small ensembles of neurons or individual neurons can only be measured using single-cell recordings obtained from largely reduced preparations. Since the expression of natural behavior is limited in restrained and dissected animals, the underlying neural mechanisms that control such behavior are difficult to identify. 
Here, I present a non-invasive physiological technique that allows measuring neural circuit activation in freely behaving animals. Using a pair of wire electrodes inside a water-filled chamber, the bath electrodes record neural and muscular field potentials generated by juvenile crayfish during natural or experimentally evoked escape responses. The primary escape responses of crayfish are mediated by three different types of tail-flips which move the animals away from the point of stimulation. Each type of tail-flip is controlled by its own neural circuit; the two fastest and most powerful escape responses require activation of different sets of large &#8220;command&#8221; neurons. In combination with behavioral observations, the bath electrode recordings allow unambiguous identification of these neurons and the associated neural circuits. Thus activity of neural circuitry underlying naturally occurring behavior can be measured in unrestrained animals and in different behavioral contexts.

Non-invasive measurements of neural activity patterns in freely behaving animals are obtained by combining neurophysiological recordings with high speed videography.

自由に動物を振る舞うの神経回路のアクティベーションの記録

The relationship between patterns of neural activity and corresponding behavioral expression is difficult to establish in unrestrained animals. ...

Aortic Ring Assay

Angiogenesis, the sprouting of blood vessels from preexisting vasculature is associated with both natural and pathological processes. Various angiogenesis assays involve the study of individual endothelial cells in culture conditions (1). The aortic ring assay is an angiogenesis model that is based on organ culture. In this assay, angiogenic vessels grow from a segment of the aorta (modified from (2)). Briefly, mouse thoracic aorta is excised, the fat layer and adventitia are removed, and rings approximately 1 mm in length are prepared. Individual rings are then embedded in a small solid dome of basement matrix extract (BME), cast inside individual wells of a 48-well plate. Angiogenic factors and inhibitors of angiogenesis can be directly added to the rings, and a mixed co-culture of aortic rings and other cell types can be employed for the study of paracrine angiogenic effects. Sprouting is observed by inspection under a stereomicroscope over a period of 6-12 days. Due to the large variation caused by the irregularities in the aortic segments, experimentation in 6-plicates is strongly advised. Neovessel outgrowth is monitored throughout the experiment and imaged using phase microscopy, and supernatants are collected for measurement of relevant angiogenic and anti-angiogenic factors, cell death markers and nitrite.

Angiogenesis, the sprouting of blood vessels from pre-existing vasculature, is associated with both natural and pathological processes. Here we demonstrate an aortic ring assay that allows angiogenic potentiators and inhibitors to be directly added to aortic rings in culture. Sprouting and neovessel outgrowth can be determined by inspecting the aortic rings over a period of 6-12 days.

大動脈リングアッセイ

Angiogenesis, the sprouting of blood vessels from preexisting vasculature is associated with both natural and pathological processes. Various angiogenesis ...

Isolation and In vitro Activation of Caenorhabditis elegans Sperm

Males and hermaphrodites are the two naturally found sexual forms in the nematode C. elegans. The amoeboid sperm are produced by both males and hermaphrodites. In the earlier phase of gametogenesis, the germ cells of hermaphrodites differentiate into limited number of sperm - around 300 - and are stored in a small 'bag' called the spermatheca. Later on, hermaphrodites continually produce oocytes1. In contrast, males produce exclusively sperm throughout their adulthood. The males produce so much sperm that it accounts for &gt;50% of the total cells in a typical adult worm2. Therefore, isolating sperm from males is easier than from that of hermaphrodites.
Only a small proportion of males are naturally generated due to spontaneous non-disjunction of X chromosome3. Crossing hermaphrodites with males or more conveniently, the introduction of mutations to give rise to Him (High Incidence of Males) phenotype are some of strategies through which one can enrich the male population3.
Males can be easily distinguished from hermaphrodites by observing the tail morphology4. Hermaphrodite's tail is pointed, whereas male tail is rounded with mating structures.
Cutting the tail releases vast number of spermatids stored inside the male reproductive tract. Dissection is performed under a stereo microscope using 27 gauge needles. Since spermatids are not physically connected with any other cells, hydraulic pressure expels internal contents of male body, including spermatids2.
Males are directly dissected on a small drop of 'Sperm Medium'. Spermatids are sensitive to alteration in the pH. Hence, HEPES, a compound with good buffering capacity is used in sperm media. Glucose and other salts present in sperm media help maintain osmotic pressure to maintain the integrity of sperm.
Post-meiotic differentiation of spermatids into spermatozoa is termed spermiogenesis or sperm activation. Shakes5, and Nelson6 previously showed that round spermatids can be induced to differentiate into spermatozoa by adding various activating compounds including Pronase E. Here we demonstrate in vitro spermiogenesis of C. elegans spermatids using Pronase E.
Successful spermiogenesis is pre-requisite for fertility and hence the mutants defective in spermiogenesis are sterile. Hitherto several mutants have been shown to be defective specifically in spermiogenesis process7. Abnormality found during in vitro activation of novel Spe (Spermatogenesis defective) mutants would help us discover additional players participating in this event.

Isolation and In vitro Activation of Caenorhabditis elegans Sperm

A protocol for isolating and activating spermatids from male C. elegans is described here. Cutting the posterior end of male releases spermatids. The spermatids can be activated by addition of protease.

アイソレーションと試験管内で</emの>活性化線虫（Caenorhabditis elegans）精子

Males and hermaphrodites are the two naturally found sexual forms in the nematode C. elegans. The amoeboid sperm are produced by both males and ...

Clonogenic Assay: Adherent Cells

The clonogenic (or colony forming) assay has been established for more than 50 years; the original paper describing the technique was published in 19561. Apart from documenting the method, the initial landmark study generated the first radiation-dose response curve for X-ray irradiated mammalian (HeLa) cells in culture1. Basically, the clonogenic assay enables an assessment of the differences in reproductive viability (capacity of cells to produce progeny; i.e. a single cell to form a colony of 50 or more cells) between control untreated cells and cells that have undergone various treatments such as exposure to ionising radiation, various chemical compounds (e.g. cytotoxic agents) or in other cases genetic manipulation. The assay has become the most widely accepted technique in radiation biology and has been widely used for evaluating the radiation sensitivity of different cell lines. Further, the clonogenic assay is commonly used for monitoring the efficacy of radiation modifying compounds and for determining the effects of cytotoxic agents and other anti-cancer therapeutics on colony forming ability, in different cell lines. A typical clonogenic survival experiment using adherent cells lines involves three distinct components, 1) treatment of the cell monolayer in tissue culture flasks, 2) preparation of single cell suspensions and plating an appropriate number of cells in petri dishes and 3) fixing and staining colonies following a relevant incubation period, which could range from 1-3 weeks, depending on the cell line. Here we demonstrate the general procedure for performing the clonogenic assay with adherent cell lines with the use of an immortalized human keratinocyte cell line (FEP-1811)2. Also, our aims are to describe common features of clonogenic assays including calculation of the plating efficiency and survival fractions after exposure of cells to radiation, and to exemplify modification of radiation-response with the use of a natural antioxidant formulation.

The applicability of the clonogenic assay for evaluating reproductive viability has been established for more than 50 years. Here we demonstrate the general procedure for performing the clonogenic assay with adherent cells.

クローン原性アッセイ：付着細胞

The clonogenic (or colony forming) assay has been established for more than 50 years; the original paper describing the technique was published in 19561. ...

Activation of Apoptosis by Cytoplasmic Microinjection of Cytochrome c

Apoptosis, or programmed cell death, is a conserved and highly regulated pathway by which cells die1. Apoptosis can be triggered when cells encounter a wide range of cytotoxic stresses. These insults initiate signaling cascades that ultimately cause the release of cytochrome c from the mitochondrial intermembrane space to the cytoplasm2. The release of cytochrome c from mitochondria is a key event that triggers the rapid activation of caspases, the key cellular proteases which ultimately execute cell death3-4.
The pathway of apoptosis is regulated at points upstream and downstream of cytochrome c release from mitochondria5. In order to study the post-mitochondrial regulation of caspase activation, many investigators have turned to direct cytoplasmic microinjection of holocytochrome c (heme-attached) protein into cells6-9. Cytochrome c is normally localized to the mitochondria where attachment of a heme group is necessary to enable it to activate apoptosis10-11. Therefore, to directly activate caspases, it is necessary to inject the holocytochrome c protein instead of its cDNA, because while the expression of cytochrome c from cDNA constructs will result in mitochondrial targeting and heme attachment, it will be sequestered from cytosolic caspases. Thus, the direct cytosolic microinjection of purified heme-attached cytochrome c protein is a useful tool to mimic mitochondrial cytochrome c release and apoptosis without the use of toxic insults which cause cellular and mitochondrial damage.
In this article, we describe a method for the microinjection of cytochrome c protein into cells, using mouse embryonic fibroblasts (MEFs) and primary sympathetic neurons as examples. While this protocol focuses on the injection of cytochrome c for investigations of apoptosis, the techniques shown here can also be easily adapted for microinjection of other proteins of interest.

Activation of Apoptosis by Cytoplasmic Microinjection of Cytochrome c

In this protocol, we describe the direct cytoplasmic microinjection of cytochrome c protein into fibroblasts and primary sympathetic neurons. This technique allows for the introduction of cytochrome c protein into the cytoplasm of cells and mimics the release of cytochrome c from mitochondria, which occurs during apoptosis.

シトクロムの細胞質マイクロインジェクションによるアポトーシスの活性化 C</em

Apoptosis, or programmed cell death, is a conserved and highly regulated pathway by which cells die1.  Apoptosis can be triggered when cells encounter a ...

Intracellular Refolding Assay

This protocol describes a method to measure the enzymatic activity of molecular chaperones in a cell-based system and the possible effects of compounds with inhibitory/stimulating activity. Molecular chaperones are proteins involved in regulation of protein folding1 and have a crucial role in promoting cell survival upon stress insults like heat shock2, nutrient starvation and exposure to chemicals/poisons3. For this reason chaperones are found to be involved in events like tumor development, chemioresistance of cancer cells4 as well as neurodegeneration5. Design of small molecules able to inhibit or stimulate the activity of these enzymes is therefore one of the most studied strategies for cancer therapy7 and neurodegenerative disorders9. The assay here described offers the possibility to measure the refolding activity of a particular molecular chaperone and to study the effect of compounds on its activity. In this method the gene of the molecular chaperone investigated is transfected together with an expression vector encoding for the firefly luciferase gene. It has been already described that denaturated firefly luciferase can be refolded by molecular chaperones10,11. As normalizing transfection control, a vector encoding for the renilla luciferase gene is transfected. All transfections described in this protocol are performed with X-treme Gene 11 (Roche) in HEK-293 cells. In the first step, protein synthesis is inhibited by treating the cells with cycloheximide. Thereafter protein unfolding is induced by heat shock at 45&deg;C for 30 minutes. Upon recovery at 37&deg;C, proteins are re-folded into their active conformation and the activity of the firefly luciferase is used as read-out: the more light will be produced, the more protein will have re-gained the original conformation. Non-heat shocked cells are set as reference (100% of refolded luciferase).

In this protocol a method to measure intracellular protein refolding after heat shock is described. This method can be used to study foldases like molecular chaperones and their co-factors or compounds able to influence their activity. Firefly luciferase activity is used as reporter to measure chaperone refolding activity.

細胞内のリフォールディングアッセイ

This protocol describes a method to measure the enzymatic activity of molecular chaperones in a cell-based system and the possible effects of compounds ...

Amide Hydrogen/Deuterium Exchange &amp; MALDI-TOF Mass Spectrometry Analysis of Pak2 Activation

Amide hydrogen/deuterium exchange (H/D exchange) coupled with mass spectrometry has been widely used to analyze the interface of protein-protein interactions, protein conformational changes, protein dynamics and protein-ligand interactions. H/D exchange on the backbone amide positions has been utilized to measure the deuteration rates of the micro-regions in a protein by mass spectrometry1,2,3. The resolution of this method depends on pepsin digestion of the deuterated protein of interest into peptides that normally range from 3-20 residues. Although the resolution of H/D exchange measured by mass spectrometry is lower than the single residue resolution measured by the Heteronuclear Single Quantum Coherence (HSQC) method of NMR, the mass spectrometry measurement in H/D exchange is not restricted by the size of the protein4. H/D exchange is carried out in an aqueous solution which maintains protein conformation. We provide a method that utilizes the MALDI-TOF for detection2, instead of a HPLC/ESI (electrospray ionization)-MS system5,6. The MALDI-TOF provides accurate mass intensity data for the peptides of the digested protein, in this case protein kinase Pak2 (also called &gamma;-Pak). Proteolysis of Pak 2 is carried out in an offline pepsin digestion. This alternative method, when the user does not have access to a HPLC and pepsin column connected to mass spectrometry, or when the pepsin column on HPLC does not result in an optimal digestion map, for example, the heavily disulfide-bonded secreted Phospholipase A2 (sPLA2). Utilizing this method, we successfully monitored changes in the deuteration level during activation of Pak2 by caspase 3 cleavage and autophosphorylation7,8,9.

MALDI-TOF mass spectrometry was successfully utilized to monitor the amide hydrogen/deuterium exchange in protein kinase Pak2 activation.

PAK2活性化のアミド水素/重水素交換とMALDI - TOF質量分析

Amide hydrogen/deuterium exchange (H/D exchange) coupled with mass spectrometry has been widely used to analyze the interface of protein-protein ...

Single-molecule Imaging of Gene Regulation In vivo Using Cotranslational Activation by Cleavage (CoTrAC)

We describe a fluorescence microscopy method, Co-Translational Activation by Cleavage (CoTrAC) to image the production of protein molecules in live cells with single-molecule precision without perturbing the protein's functionality. This method makes it possible to count the numbers of protein molecules produced in one cell during sequential, five-minute time windows. It requires a fluorescence microscope with laser excitation power density of ~0.5 to 1 kW/cm2, which is sufficiently sensitive to detect single fluorescent protein molecules in live cells. The fluorescent reporter used in this method consists of three parts: a membrane targeting sequence, a fast-maturing, yellow fluorescent protein and a protease recognition sequence. The reporter is translationally fused to the N-terminus of a protein of interest. Cells are grown on a temperature-controlled microscope stage. Every five minutes, fluorescent molecules within cells are imaged (and later counted by analyzing fluorescence images) and subsequently photobleached so that only newly translated proteins are counted in the next measurement.
Fluorescence images resulting from this method can be analyzed by detecting fluorescent spots in each image, assigning them to individual cells and then assigning cells to cell lineages. The number of proteins produced within a time window in a given cell is calculated by dividing the integrated fluorescence intensity of spots by the average intensity of single fluorescent molecules. We used this method to measure expression levels in the range of 0-45 molecules in single 5 min time windows. This method enabled us to measure noise in the expression of the &lambda; repressor CI, and has many other potential applications in systems biology.

Single-molecule Imaging of Gene Regulation In vivo Using Cotranslational Activation by Cleavage CoTrAC

We describe a fluorescence microscopy method, Co-Translational Activation by Cleavage (CoTrAC), to image the production of protein molecules in live cells with single-molecule precision without perturbing the protein's functionality. This method has been used to follow the stochastic expression dynamics of a transcription factor, the &lambda; repressor CI 1.

遺伝子調節の1分子蛍光イメージング<emインビボ&gt;</em&gt;開裂により同時翻訳アクティベーションの使用（CoTrAC）

We describe a fluorescence microscopy method, Co-Translational Activation by Cleavage (CoTrAC) to image the production of protein molecules in live cells ...

C. elegans Chemotaxis Assay

Many organisms use chemotaxis to seek out food sources, avoid noxious substances, and find mates. Caenorhabditis elegans has impressive chemotaxis behavior.
 The premise behind testing the response of the worms to an odorant is to place them in an area and observe the movement evoked in response to an odorant. Even with the many available assays, optimizing worm starting location relative to both the control and test areas, while minimizing the interaction of worms with each other, while maintaining a significant sample size remains a work in progress 1-10. The method described here aims to address these issues by modifying the assay developed by Bargmann et al.1. A Petri dish is divided into four quadrants, two opposite quadrants marked "Test" and two are designated "Control". Anesthetic is placed in all test and control sites. The worms are placed in the center of the plate with a circle marked around the origin to ensure that non-motile worms will be ignored. Utilizing a four-quadrant system rather than one 2 or two 1 eliminates bias in the movement of the worms, as they are equidistant from test and control samples, regardless of which side of the origin they began. This circumvents the problem of worms being forced to travel through a cluster of other worms to respond to an odorant, which can delay worms or force them to take a more circuitous route, yielding an incorrect interpretation of their intended path. This method also shows practical advantages by having a larger sample size and allowing the researcher to run the assay unattended and score the worms once the allotted time has expired.

C. elegans Chemotaxis Assay

A method of quantitatively evaluating the chemotactic response of Caenorhabditis elegans is described. A chemotactic index (CI) was employed as a way to precisely evaluate the response of worms to certain targets, and serve as a platform of comparison between strains and compounds of interest.

C. elegansの走化性アッセイ

Many organisms use chemotaxis to seek out food sources, avoid noxious substances, and find mates.  Caenorhabditis elegans has impressive chemotaxis ...