This work was supported by an NSF/ARRA award (IOS 0920357) and an award from the NIH (5R21MH098463).

1. خلية إعداد (اليوم -2 إلى 0) <ol style=";text-align:right;direction:rtl"><li style=";text-align:right;direction:rtl"> انقسام خلايا HEK293 1: 5 باستخدام 0.05٪ التربسين-EDTA الحل واحتضان وسائل الإعلام في النمو عند 37 درجة مئوية مع 5٪ CO 2 حتى 60-80٪ متموجة (2 - 3 أيام). لكل حالة، وخلايا الثقافة في 2 × 100 ملم الأطباق. </li></ol> 2. ترنسفكأيشن الخلية (يوم 1) <ol style=";text-align:right;direction:rtl"><li style=";text-align:right;direction:rtl"> بالنقل خلايا HEK293 مع ترميز البلازميد FC-الانصهار باستخدام كاشف ترنسفكأيشن مثل Lipofectamine. كما يمكن استخدام طرق بديلة تؤدي إلى الكفاءة ترنسفكأيشن مماثلة. </li><li style=";text-align:right;direction:rtl"> العودة الخلايا المصابة بالعدوى بالنقل إلى الحاضنة لمدة 24 ساعة. </li></ol> 3. خلية الانتشار (اليوم 2) <ol style=";text-align:right;direction:rtl"><li style=";text-align:right;direction:rtl"> وسائط النمو سخن دون مصل بقري جنيني (-FBS) إلى 37 درجة مئوية. </li><li style=";text-align:right;direction:rtl"> شطف الأطباق 2X مع 10 مل نمو وسائل الإعلام -FBS، والعودة الأطباق إلى الحاضنة 37 درجة مئوية لمدة 1 ساعة. </li><li style=";text-align:right;direction:rtl"> شطف الأطباق الثقافات واحد المزيد من الوقت مع 10 مل نمو وسائل الإعلام -FBS، أي ما مجموعه 3 يغسل. </li><li style=";text-align:right;direction:rtl"> Incuباتي الخلايا HEK293 transfected عند 37 درجة مئوية لمدة 48 ساعة أخرى دون FBS قبل جمع سائل الإعلام. </li></ol> 4. الخرزة تجميع (اليوم 4) <ol style=";text-align:right;direction:rtl"><li style=";text-align:right;direction:rtl"> لجمع وسائل الاعلام من الأطباق الثقافة، ونقل وسائل الاعلام من كل زوج من الأطباق إلى 50 مل أنابيب مخروطية وتدور في 500 x ج لمدة 5 دقائق لتكوير الحطام الخلوي. </li><li style=";text-align:right;direction:rtl"> فلتر وسائل الاعلام من 50 مل أنبوب مخروطي إلى تصفية الطرد المركزي باستخدام حقنة 30 مل و 0.45 ميكرون فلتر حقنة. </li><li style=";text-align:right;direction:rtl"> تدور مرشحات الطرد المركزي في 4000 x ج و 4 درجات مئوية حتى حجم سائل الإعلام والثقافة المركزة حوالي 500 ميكرولتر (حوالي 15 دقيقة). كرر حتى تمت إضافة كافة وسائل الإعلام والثقافة، وتتركز. </li><li style=";text-align:right;direction:rtl"> إضافة 1.5 ميكرولتر من بروتين G حبات مغناطيسية إلى 1 مل من الجليد الباردة الاحتياطي ملزم في أنبوب microcentrifuge 1.5 مل لكل عينة، ومكان على المغناطيس وإزالة العازلة. على الفور إضافة وسائل الإعلام الثقافة المركزة للبروتين G حبات المغناطيسي. </li><li style=";text-align:right;direction:rtl"> تدوير أنابيب في 4 درجة مئوية لمدة 2 ساعة. </li><li style=";text-align:right;direction:rtl"> ررأنابيب الآس على المغناطيس وإزالة وسائل الإعلام. تغسل حبات بسرعة مرتين مع الجليد الباردة 1 مل الاحتياطي ملزم، وresuspend ثم الخرز في 300 ميكرولتر الاحتياطي ملزم. </li><li style=";text-align:right;direction:rtl"> سبليت معلق حبات في 2 أنابيب، 150 ميكرولتر إلى كل أنبوب، ثم قم بإضافة 1.5 ميكرولتر من 200 مم CaCl 2 أو 200 ملي EDTA ل &quot;الكالسيوم&quot; والشروط &quot;لا الكالسيوم&quot;، على التوالي. </li><li style=";text-align:right;direction:rtl"> نقل 100 ميكرولتر من كل حالة إلى الاكتئاب الشريحة بشكل جيد وجمع الميكروسكوب باستخدام مجهر الضوء المرسل (الشكل 2). جمع الصور من 5 حقول نظر لكل تجربة في كل نقطة زمنية المطلوب. </li></ol> تحليل البيانات 5. <ol style=";text-align:right;direction:rtl"><li style=";text-align:right;direction:rtl"> باستخدام يماغيج، أو يعادل برنامج تحليل الصور، وفتح واحدة من مجموعات البيانات باستخدام صورة خمس استيراد / صورة تسلسل ... من القائمة المنسدلة ملف. سيتم فتح هذه باعتبارها كومة الصورة. </li><li style=";text-align:right;direction:rtl"> في الصور / ... خصائص مربع الحوار، تغيير طوحدات بركه إلى بكسل ووضع العرض بكسل والارتفاع إلى 1.0 بكسل. </li><li style=";text-align:right;direction:rtl"> تحويل الصور إلى ثنائي باستخدام ضبط / عتبة ... الأمر في القائمة المنسدلة صورة. تعيين عتبة لتشمل بكسل التي تساهم في حبة الخرز أو المجاميع، ولكن تستبعد الخلفية والجسيمات الصغيرة. تنطبق على جميع الصور في المكدس. </li><li style=";text-align:right;direction:rtl"> في مربع الحوار القياسات مجموعة، حدد المربعات منطقة والمكدس الموقع. </li><li style=";text-align:right;direction:rtl"> تشغيل تحليل الجسيمات ... في تحليل القائمة المنسدلة. هذا سوف إنشاء قائمة من الجسيمات التي تم تحديدها، بما في ذلك حجمها (منطقة) والصورة التي تم تحديدها. </li><li style=";text-align:right;direction:rtl"> كرر هذه العملية التي تجربة وحالة تجريبية. </li></ol>

<ol>
	<li>Chen, X., Gumbiner, B. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Paraxial+protocadherin+mediates+cell+sorting+and+tissue+morphogenesis+by+regulating+C-cadherin+adhesion+activity.">Paraxial protocadherin mediates cell sorting and tissue morphogenesis by regulating C-cadherin adhesion activity.</a> J. Cell Biol. 174 (2), 301-313 (2006).</li><li>Grumet, M., Friedlander, D. R., Edelman, G. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Evidence+for+the+binding+of+Ng-CAM+to+laminin.">Evidence for the binding of Ng-CAM to laminin.</a> Cell Adhes. Commun. 1 (2), 177-190 (1993).</li><li>Hatta, K., Nose, A., Nagafuchi, A., Takeichi, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cloning+and+expression+of+cDNA+encoding+a+neural+calcium-dependent+cell+adhesion+molecule:+its+identity+in+the+cadherin+gene+family.">Cloning and expression of cDNA encoding a neural calcium-dependent cell adhesion molecule: its identity in the cadherin gene family.</a> J. Cell Biol. 106 (3), 873-881 (1988).</li><li>Hirano, S., Nose, A., Hatta, K., Kawakami, A., Takeichi, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Calcium-dependent+cell-cell+adhesion+molecules+(cadherins):+subclass+specificities+and+possible+involvement+of+actin+bundles.">Calcium-dependent cell-cell adhesion molecules (cadherins): subclass specificities and possible involvement of actin bundles.</a> J. Cell Biol. 105 (6 Pt 1), 2501-2510 (1987).</li><li>Nose, A., Nagafuchi, A., Takeichi, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Expressed+recombinant+cadherins+mediate+cell+sorting+in+model+systems.">Expressed recombinant cadherins mediate cell sorting in model systems.</a> Cell. 54 (7), 993-1001 (1988).</li><li>Nose, A., Takeichi, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+novel+cadherin+cell+adhesion+molecule:+its+expression+patterns+associated+with+implantation+and+organogenesis+of+mouse+embryos.">A novel cadherin cell adhesion molecule: its expression patterns associated with implantation and organogenesis of mouse embryos.</a> J. Cell Biol. 103 (6 Pt 2), 2649-2658 (1986).</li><li>Schreiner, D., Weiner, J. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Combinatorial+homophilic+interaction+between+gamma-protocadherin+multimers+greatly+expands+the+molecular+diversity+of+cell+adhesion.">Combinatorial homophilic interaction between gamma-protocadherin multimers greatly expands the molecular diversity of cell adhesion.</a> Proc. Natl. Acad. Sci. U. S. A. 107 (33), 14893-14898 (2010).</li><li>Takeichi, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Functional+correlation+between+cell+adhesive+properties+and+some+cell+surface+proteins.">Functional correlation between cell adhesive properties and some cell surface proteins.</a> J. Cell Biol. 75, 464-474 (1977).</li><li>Sivasankar, S., Brieher, W., Lavrik, N., Gumbiner, B., Leckband, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Direct+molecular+force+measurements+of+multiple+adhesive+interactions+between+cadherin+ectodomains.">Direct molecular force measurements of multiple adhesive interactions between cadherin ectodomains.</a> Proc. Natl. Acad. Sci. U. S. A. 96 (21), 11820-11824 (1999).</li><li>Sivasankar, S., Gumbiner, B., Leckband, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Direct+measurements+of+multiple+adhesive+alignments+and+unbinding+trajectories+between+cadherin+extracellular+domains.">Direct measurements of multiple adhesive alignments and unbinding trajectories between cadherin extracellular domains.</a> Biophys. J. 80, 1758-1768 (2001).</li><li>Sivasankar, S., Zhang, Y., Nelson, W. J., Chu, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Characterizing+the+initial+encounter+complex+in+cadherin+adhesion.">Characterizing the initial encounter complex in cadherin adhesion.</a> Structure. 17 (8), 1075-1081 (2009).</li><li>Zhang, Y., Sivasankar, S., Nelson, W. J., Chu, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Resolving+cadherin+interactions+and+binding+cooperativity+at+the+single-molecule+level.">Resolving cadherin interactions and binding cooperativity at the single-molecule level.</a> Proc. Natl. Acad. Sci. U. S. A. 106 (1), 109-114 (2009).</li><li>Yasuda, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Activity-induced+protocadherin+arcadlin+regulates+dendritic+spine+number+by+triggering+N-cadherin+endocytosis+via+TAO2beta+and+p38+MAP+kinases.">Activity-induced protocadherin arcadlin regulates dendritic spine number by triggering N-cadherin endocytosis via TAO2beta and p38 MAP kinases.</a> Neuron. 56 (3), 456-471 (2007).</li><li>Chappuis-Flament, S., Wong, E., Hicks, L. D., Kay, C. M., Gumbiner, B. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Multiple+cadherin+extracellular+repeats+mediate+homophilic+binding+and+adhesion.">Multiple cadherin extracellular repeats mediate homophilic binding and adhesion.</a> J. Cell Biol. 154 (1), 231-243 (2001).</li><li>Emond, M. R., Biswas, S., Blevins, C. J., Jontes, J. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+complex+of+Protocadherin-19+and+N-cadherin+mediates+a+novel+mechanism+of+cell+adhesion.">A complex of Protocadherin-19 and N-cadherin mediates a novel mechanism of cell adhesion.</a> J. Cell Biol. 195 (7), 1115-1121 (2011).</li><li>Biswas, S., Emond, M. R., Jontes, J. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+clustered+protocadherins+Pcdhalpha+and+Pcdhgamma+form+a+heteromeric+complex+in+zebrafish.">The clustered protocadherins Pcdhalpha and Pcdhgamma form a heteromeric complex in zebrafish.</a> Neuroscience. 219, 280-289 (2012).</li><li>Blevins, C. J., Emond, M. R., Biswas, S., Jontes, J. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Differential+expression,+alternative+splicing,+and+adhesive+properties+of+the+zebrafish+delta1-protocadherins.">Differential expression, alternative splicing, and adhesive properties of the zebrafish delta1-protocadherins.</a> Neuroscience. 199, 523-534 (2011).</li><li>Morishita, H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Structure+of+the+cadherin-related+neuronal+receptor/protocadherin-alpha+first+extracellular+cadherin+domain+reveals+diversity+across+cadherin+families.">Structure of the cadherin-related neuronal receptor/protocadherin-alpha first extracellular cadherin domain reveals diversity across cadherin families.</a> J. Biol. Chem. 281, 33650-33663 (1074).</li><li>Wojtowicz, W. M., Flanagan, J. J., Millard, S. S., Zipursky, S. L., Clemens, J. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Alternative+splicing+of+Drosophila+Dscam+generates+axon+guidance+receptors+that+exhibit+isoform-specific+homophilic+binding.">Alternative splicing of Drosophila Dscam generates axon guidance receptors that exhibit isoform-specific homophilic binding.</a> Cell. 118 (5), 619-633 (2004).</li><li>Drees, F., Reilein, A., Nelson, W. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cell-adhesion+assays:+fabrication+of+an+E-cadherin+substratum+and+isolation+of+lateral+and+Basal+membrane+patches.">Cell-adhesion assays: fabrication of an E-cadherin substratum and isolation of lateral and Basal membrane patches.</a> Methods Mol. Biol. 294, 303-320 (2005).</li></ol>

The authors declare that they have no competing financial interests.

التصاق الخلية هو سمة أساسية من سمات الحياة متعددة الخلايا وبوساطة مجموعة واسعة من بروتينات سطح الخلية. من هذه، وفهم الخصائص التفصيلية لاصقة سوى نسبة صغيرة نسبيا. هنا، التي وصفناها بروتوكول بسيطة وسريعة للتحقيق في قدرة لاصقة مقتصر على المطابق من ectodomains يفرز تنصهر علا...

التصاق خلية خلية ضروري لتطوير وسلامة الكائنات متعددة الخلايا وبوساطة مجموعة متنوعة من جزيئات سطح الخلية. وقد تم تحديد العديد من هذه جزيئات الالتصاق ويتميز، رغم أن الكثيرين لا يزال يتعين اكتشافها. وتستخدم عدة طرق لتحقيق خصائص خلية التصاق جزيئات (الحدب)، بما في ذلك الخلايا فرز فحوصات، فحوصات تجميع خلية 1-8 والأساليب الفيزيائية الحيوية، مثل مجهر القوة الذرية والسطحية قوة التحليل الطيفي 9-12. تعقيد حتى مبسطة في أنظمة المختبر باستخدام خطوط الخلايا يجعل من الصعب تحديد خصائص لاصقة من المفترض CAM. عادة، يعتبر جزيء وCAM إذا كان يدفع تجميع الخلايا عندما transfected في خط خلية غير لاصقة. ومع ذلك، فمن الواضح أن هذا ليس دليل مباشر على النشاط اصقة. على سبيل المثال، وتسهيل إيصال سطح الخلية أو استقرارسوف CAM يؤدي أيضا إلى زيادة تجميع خلية 1،13. وعلاوة على ذلك، قد تفشل CAM صحيح للتوسط تجميع خلية إذا كان خط الخلية تفتقر العوامل المشتركة الأخرى المطلوبة للتسليم سطح الخلية أو الاستقرار. لتجنب هذه العوامل المعقدة، والمزيد من المقايسات المباشرة يمكن استخدامها التي تستند على فكرة أن التفاعلات لاصقة يجب أن تكون خاصية البيوكيميائية الجوهرية المجال خارج الخلية. بينما الخرز المستخدمة في البداية لوصف NG-CAM 2، وقد تم تمديد هذه المقايسات من أجل التحقيق بوساطة كادهيرين التصاق 12،14،15. باستخدام الانصهار من C-كادهيرين اندماج ectodomain-FC، أظهر مختبر Gumbiner أن يكرر كادهيرين متعددة تساهم في التفاعلات مقتصر على المطابق 14. عن طريق مقارنة المقايسات حبة التجميع، E-كادهيرين وN-كادهيرين التصاق كما تم يتميز 12،15، وكذلك عدد من protocadherins 1،15-18 والإسوية Dscam من ذبابة الفاكهة <em&gt; 19. نحن هنا وصف مقايسة بسيطة نسبيا وسريع لوصف النشاط لاصقة من يفرز، ectodomains الموسومة حاتمة من الحدب مقتصر على المطابق المفترضة (الشكل 1). وقد استخدمنا هذا الاختبار في المقام الأول إلى تميز أعضاء الفصيلة كادهيرين.

<table border="0" cellpadding="0" cellspacing="0" width="630">
	<tbody>
		<tr height="43">
			<td height="43" style="height:43px;width:212px;">Name of Material/ Equipment</td>
			<td style="width:203px;">Catalog Number</td>
			<td style="width:216px;">Company</td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:212px;">pFc-N1 plasmid</td>
			<td style="width:203px;">To be submitted</td>
			<td style="width:216px;">Addgene</td>
		</tr>
		<tr height="41">
			<td height="41" style="height:41px;width:212px;">HEK293 cells</td>
			<td style="width:203px;">CRL-1573</td>
			<td style="width:216px;">American Type Culture Collection</td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:212px;">DMEM</td>
			<td style="width:203px;">10-013-CV</td>
			<td style="width:216px;">Mediatech - Corning</td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:212px;">Fetal Bovine Serum (FBS)</td>
			<td style="width:203px;">F2442</td>
			<td style="width:216px;">Sigma</td>
		</tr>
		<tr height="41">
			<td height="41" style="height:41px;width:212px;">100X Pen-Strep (10,000 U/ml)</td>
			<td style="width:203px;">15140-122</td>
			<td style="width:216px;">Life Technologies</td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:212px;">0.05% Trypsin-EDTA</td>
			<td style="width:203px;">25300054</td>
			<td style="width:216px;">Life Technologies</td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:212px;">Lipofectamine 2000</td>
			<td style="width:203px;">11668030</td>
			<td style="width:216px;">Life Technologies</td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:212px;">Dynabeads &#8211; Protein G</td>
			<td style="width:203px;">10003D</td>
			<td style="width:216px;">Life Technologies</td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:212px;">Bovine Serum Albumin</td>
			<td style="width:203px;">A3294</td>
			<td style="width:216px;">Sigma</td>
		</tr>
		<tr height="41">
			<td height="41" style="height:41px;width:212px;">Depression slides</td>
			<td style="width:203px;">71878-06</td>
			<td style="width:216px;">Electron Microscopy Sciences</td>
		</tr>
		<tr height="21">
			<td height="43" rowspan="2" style="height:43px;width:212px;">Amicon Ultra-15 Centrifugal Filter Unit with Ultracel-10 membrane</td>
			<td rowspan="2" style="width:203px;">UFC901024</td>
			<td rowspan="2" style="width:216px;">Millipore</td>
		</tr>
		<tr height="22">
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:212px;">0.45mm syringe filter</td>
			<td style="width:203px;">83.1826</td>
			<td style="width:216px;">Sarstedt</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:212px;">Dynamag-2 Magnet</td>
			<td>12321D</td>
			<td style="width:216px;">Life Technologies</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:43px;width:212px;">Fiji (ImageJ) Image Analysis Software</td>
			<td style="width:203px;"></td>
			<td style="width:216px;">http://fiji.sc/Fiji</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:212px;"></td>
			<td style="width:203px;"></td>
			<td style="width:216px;"></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:212px;"></td>
			<td style="width:203px;"></td>
			<td style="width:216px;"></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:212px;"></td>
			<td style="width:203px;"></td>
			<td style="width:216px;"></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:212px;"></td>
			<td style="width:203px;"></td>
			<td style="width:216px;"></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:212px;">Table of Buffers/Solutions</td>
			<td style="width:203px;"></td>
			<td style="width:216px;"></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:212px;"></td>
			<td style="width:203px;"></td>
			<td style="width:216px;"></td>
		</tr>
		<tr height="41">
			<td height="41" style="height:41px;width:212px;">Growth Media</td>
			<td style="width:203px;">DMEM + 10% FBS + Pen-Strep</td>
			<td style="width:216px;">Filter sterilize and store at 4&#176;C.</td>
		</tr>
		<tr height="41">
			<td height="41" style="height:41px;width:212px;">Growth Media &#8211; FBS</td>
			<td style="width:203px;">DMEM + Pen-Strep</td>
			<td style="width:216px;">Filter sterilize and store at 4&#176;C.</td>
		</tr>
		<tr height="61">
			<td height="61" style="height:61px;width:212px;">Binding Buffer</td>
			<td style="width:203px;">50 mM Tris, pH 7.4, 100 mM NaCl, 10 mM KCl, 0.2% BSA</td>
			<td style="width:216px;">Vortex until dissolved, keep on ice.</td>
		</tr>
	</tbody>
</table>

bead aggregation assays for the characterization of putative cell adhesion molecules

التصاق خلية خلية هو الأساسي في الحياة متعددة الخلايا وبوساطة مجموعة متنوعة من بروتينات سطح الخلية. ومع ذلك، يتم مفهومة التفاعلات لاصقة لكثير من هذه البروتينات. هنا نقدم طريقة بسيطة وسريعة لوصف خصائص لاصقة من المفترضة مقتصر على المطابق جزيئات التصاق الخلية. و transfected خلايا HEK293 مثقف مع بلازميد الحمض النووي ترميز يفرز،، حاتمة الموسومة ectodomain من بروتين سطح الخلية. باستخدام الخرز بين functionalized محددة للعلامة حاتمة، يتم التقاط القابلة للذوبان، انصهار بروتين يفرز من مستنبت. ويمكن بعد ذلك حبات المغلفة استخدامها مباشرة في حبة المقايسات التجميع أو في حبة الفلورسنت فرز فحوصات لاختبار التصاق مقتصر على المطابق. إذا رغبت، الطفرات يمكن بعد ذلك أن تستخدم لتوضيح الأحماض الأمينية المحددة أو المجالات المطلوبة للالتصاق. هذا الاختبار يتطلب سوى كميات صغيرة من البروتين المعبر عنها، لا يتطلب إنتاج خطوط الخلايا مستقرة، ويمكن عكاmplished في 4 أيام.

<html> وتقدم تجربة سبيل المثال في الشكل 2، مما يدل تعتمد على الكالسيوم حبة تجميع من قبل ectodomain من N-كادهيرين تنصهر لجنة التيسير (NcadEC-FC). في غياب الكالسيوم، والخرز تظهر نزعة ضئيلة أو معدومة لتجميع وليس هناك زيادة في الحجم الكلي مع الزمن (الشكل 1A، C). في وجود ا...

Watch this Scientific Journal Video about Bead Aggregation Assays for the Characterization of Putative Cell Adhesion Molecules at JoVE.com

Bead Aggregation Assays for the Characterization of Putative Cell Adhesion Molecules

Here we present a simple, rapid method for characterizing the intrinsic adhesive properties of putative cell adhesion molecules. The secreted, epitope-tagged ectodomain of a cell adhesion molecule is captured from the culture medium on small, uniform functionalized beads. These beads can then be used immediately in simple bead aggregation assays.

حبة تجميع فحوصات لتوصيف المزعومين خلية التصاق جزيئات

Cell-cell adhesion is fundamental to multicellular life and is mediated by a diverse array of cell surface proteins. However, the adhesive interactions ...

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10.4K Views.  Ohio State University. Here we present a simple, rapid method for characterizing the intrinsic adhesive properties of putative cell adhesion molecules. The secreted, epitope-tagged ectodomain of a cell adhesion molecule is captured from the culture medium on small, uniform functionalized beads. These beads can then be used immediately in simple bead aggregation assays.

Video: Bead Aggregation Assays for the Characterization of Putative Cell Adhesion Molecules

Synthesis, Assembly, and Characterization of Monolayer Protected Gold Nanoparticle Films for Protein Monolayer Electrochemistry

Colloidal gold nanoparticles protected with alkanethiolate ligands called monolayer protected gold clusters (MPCs) are synthesized and subsequently incorporated into film assemblies that serve as adsorption platforms for protein monolayer electrochemistry (PME). PME is utilized as the model system for studying electrochemical properties of redox proteins by confining them to an adsorption platform at a modified electrode, which also serves as a redox partner for electron transfer (ET) reactions. Studies have shown that gold nanoparticle film assemblies of this nature provide for a more homogeneous protein adsorption environment and promote ET without distance dependence compared to the more traditional systems modified with alkanethiol self-assembled monolayers (SAM).1-3 In this paper, MPCs functionalized with hexanethiolate ligands are synthesized using a modified Brust reaction4 and characterized with ultraviolet visible (UV-Vis) spectroscopy, transmission electron microscopy (TEM), and proton (1H) nuclear magnetic resonance (NMR). MPC films are assembled on SAM modified gold electrode interfaces by using a "dip cycle" method of alternating MPC layers and dithiol linking molecules. Film growth at gold electrode is tracked electrochemically by measuring changes to the double layer charging current of the system. Analogous films assembled on silane modified glass slides allow for optical monitoring of film growth and cross-sectional TEM analysis provides an estimated film thickness. During film assembly, manipulation of the MPC ligand protection as well as the interparticle linkage mechanism allow for networked films, that are readily adaptable, to interface with redox protein having different adsorption mechanism. For example, Pseudomonas aeruginosa azurin (AZ) can be adsorbed hydrophobically to dithiol-linked films of hexanethiolate MPCs and cytochrome c (cyt c) can be immobilized electrostatically at a carboxylic acid modified MPC interfacial layer. In this report, we focus on the film protocol for the AZ system exclusively. Investigations involving the adsorption of proteins on MPC modified synthetic platforms could further the understanding of interactions between biomolecules and man-made materials, and consequently aid the development of biosensor schemes, ET modeling systems, and synthetic biocompatible materials.5-8

Alkanethiolate stabilized gold colloids known as monolayer protected clusters (MPCs) are synthesized, characterized, and assembled into thin films as an adsorption interface for protein monolayer electrochemistry of simple redox protein like Pseudomonas aeruginosa azurin (AZ) and cytochrome c (cyt c).

التوليف ، والجمعية ، وتوصيف أحادي الطبقة المحمية الجسيمات النانوية الذهبية للأفلام كهربية البروتين أحادي الطبقة

Colloidal gold nanoparticles protected with alkanethiolate ligands called monolayer protected gold clusters (MPCs) are synthesized and subsequently ...

Adhesion Frequency Assay for In Situ Kinetics Analysis of Cross-Junctional Molecular Interactions at the Cell-Cell Interface

The micropipette adhesion assay was developed in 1998 to measure two-dimensional (2D) receptor-ligand binding kinetics1. The assay uses a human red blood cell (RBC) as adhesion sensor and presenting cell for one of the interacting molecules. It employs micromanipulation to bring the RBC into contact with another cell that expresses the other interacting molecule with precisely controlled area and time to enable bond formation. The adhesion event is detected as RBC elongation upon pulling the two cells apart. By controlling the density of the ligands immobilized on the RBC surface, the probability of adhesion is kept in mid-range between 0 and 1. The adhesion probability is estimated from the frequency of adhesion events in a sequence of repeated contact cycles between the two cells for a given contact time. Varying the contact time generates a binding curve. Fitting a probabilistic model for receptor-ligand reaction kinetics1 to the binding curve returns the 2D affinity and off-rate.
The assay has been validated using interactions of Fc&gamma; receptors with IgG Fc1-6, selectins with glycoconjugate ligands6-9, integrins with ligands10-13, homotypical cadherin binding14, T cell receptor and coreceptor with peptide-major histocompatibility complexes15-19.
The method has been used to quantify regulations of 2D kinetics by biophysical factors, such as the membrane microtopology5, membrane anchor2, molecular orientation and length6, carrier stiffness9, curvature20, and impingement force20, as well as biochemical factors, such as modulators of the cytoskeleton and membrane microenvironment where the interacting molecules reside and the surface organization of these molecules15,17,19.
The method has also been used to study the concurrent binding of dual receptor-ligand species3,4, and trimolecular interactions19 using a modified model21.
The major advantage of the method is that it allows study of receptors in their native membrane environment. The results could be very different from those obtained using purified receptors17. It also allows study of the receptor-ligand interactions in a sub-second timescale with temporal resolution well beyond the typical biochemical methods.
To illustrate the micropipette adhesion frequency method, we show kinetics measurement of intercellular adhesion molecule 1 (ICAM-1) functionalized on RBCs binding to integrin &alpha;L&beta;2 on neutrophils with dimeric E-selectin in the solution to activate &alpha;L&beta;2.

Adhesion Frequency Assay for In Situ Kinetics Analysis of Cross-Junctional Molecular Interactions at the Cell-Cell Interface

An adhesion frequency assay for measuring receptor-ligand interaction kinetics when both molecules are anchored on the surfaces of the interacting cells is described. This mechanically-based assay is exemplified using a micropipette-pressurized human red blood cell as adhesion sensor and integrin &alpha;L&beta;2 and intercellular adhesion molecule-1 as interacting receptors and ligands.

التصاق الفحص عن التردد في الموقع تحليل حركية عبر صلي التفاعلات الجزيئية في خلية واجهة سيل

The micropipette adhesion assay was developed in 1998 to measure two-dimensional (2D) receptor-ligand binding kinetics1. The assay uses a human red blood ...

Using Cell-substrate Impedance and Live Cell Imaging to Measure Real-time Changes in Cellular Adhesion and De-adhesion Induced by Matrix Modification

Cell-matrix adhesion plays a key role in controlling cell morphology and signaling. Stimuli that disrupt cell-matrix adhesion (e.g., myeloperoxidase and other matrix-modifying oxidants/enzymes released during inflammation) are implicated in triggering pathological changes in cellular function, phenotype and viability in a number of diseases. Here, we describe how cell-substrate impedance and live cell imaging approaches can be readily employed to accurately quantify real-time changes in cell adhesion and de-adhesion induced by matrix modification (using endothelial cells and myeloperoxidase as a pathophysiological matrix-modifying stimulus) with high temporal resolution and in a non-invasive manner. The xCELLigence cell-substrate impedance system continuously quantifies the area of cell-matrix adhesion by measuring the electrical impedance at the cell-substrate interface in cells grown on gold microelectrode arrays. Image analysis of time-lapse differential interference contrast movies quantifies changes in the projected area of individual cells over time, representing changes in the area of cell-matrix contact. Both techniques accurately quantify rapid changes to cellular adhesion and de-adhesion processes. Cell-substrate impedance on microelectrode biosensor arrays provides a platform for robust, high-throughput measurements. Live cell imaging analyses provide additional detail regarding the nature and dynamics of the morphological changes quantified by cell-substrate impedance measurements. These complementary approaches provide valuable new insights into how myeloperoxidase-catalyzed oxidative modification of subcellular extracellular matrix components triggers rapid changes in cell adhesion, morphology and signaling in endothelial cells. These approaches are also applicable for studying cellular adhesion dynamics in response to other matrix-modifying stimuli and in related adherent cells (e.g., epithelial cells).

Here, we present a protocol to continuously quantify cell adhesion and de-adhesion processes with high temporal resolution in a non-invasive manner by cell-substrate impedance and live cell imaging analyses. These approaches reveal the dynamics of cell adhesion/de-adhesion processes triggered by matrix modification and their temporal relationship to adhesion-dependent signaling events.

باستخدام الممانعة الخلوي الركيزة ويعيش التصوير خلية قياس التغييرات في الوقت الحقيقي في التصاق الخلوية ودي التصاق المستحث بواسطة مصفوفة تعديل

Cell-matrix adhesion plays a key role in controlling cell morphology and signaling. Stimuli that disrupt cell-matrix adhesion (e.g., myeloperoxidase and ...

Controlled Microfluidic Environment for Dynamic Investigation of Red Blood Cell Aggregation

Blood, as a non-Newtonian biofluid, represents the focus of numerous studies in the hemorheology field. Blood constituents include red blood cells, white blood cells and platelets that are suspended in blood plasma. Due to the abundance of the RBCs (40% to 45% of the blood volume), their behavior dictates the rheological behavior of blood especially in the microcirculation. At very low shear rates, RBCs are seen to assemble and form entities called aggregates, which causes the non-Newtonian behavior of blood. It is important to understand the conditions of the aggregates formation to comprehend the blood rheology in microcirculation. The protocol described here details the experimental procedure to determine quantitatively the RBC aggregates in microcirculation under constant shear rate, based on image processing. For this purpose, RBC-suspensions are tested and analyzed in 120 x 60 &#181;m poly-dimethyl-siloxane (PDMS) microchannels. The RBC-suspensions are entrained using a second fluid in order to obtain a linear velocity profile within the blood layer and thus achieve a wide range of constant shear rates. The shear rate is determined using a micro Particle Image Velocimetry (&#181;PIV) system, while RBC aggregates are visualized using a high speed camera. The videos captured of the RBC aggregates are analyzed using image processing techniques in order to determine the aggregate sizes based on the images intensities.

The protocol described details an experimental procedure to quantify Red Blood Cell (RBC) aggregates under a controlled and constant shear rate, based on image processing techniques. The goal of this protocol is to relate RBC aggregate sizes to the corresponding shear rate in a controlled microfluidic environment.

تسيطر البيئة الميكروية للتحقيق ديناميكية الدم الحمراء تجميع خلية

Blood, as a non-Newtonian biofluid, represents the focus of numerous studies in the hemorheology field. Blood constituents include red blood cells, white ...

Wet Chemistry and Peptide Immobilization on Polytetrafluoroethylene for Improved Cell-adhesion

Endowing materials surface with cell-adhesive properties is a common strategy in biomaterial research and tissue engineering. This is particularly interesting for already approved polymers that have a long standing use in medicine because these materials are well characterized and legal issues associated with the introduction of newly synthesized polymers may be avoided. Polytetrafluoroethylene (PTFE) is one of the most frequently employed materials for the manufacturing of vascular grafts but the polymer lacks cell adhesion promoting features. Endothelialization, i.e., complete coverage of the grafts inner surface with a confluent layer of endothelial cells is regarded key to optimal performance, mainly by reducing thrombogenicity of the artificial interface.
This study investigates the growth of endothelial cells on peptide-modified PTFE and compares these results to those obtained on unmodified substrate. Coupling with the endothelial cell adhesive peptide Arg-Glu-Asp-Val (REDV) is performed via activation of the fluorin-containing polymer using the reagent sodium naphthalenide, followed by subsequent conjugation steps. Cell culture is accomplished using Human Umbilical Vein Endothelial Cells (HUVECs) and excellent cellular growth on peptide-immobilized material is demonstrated over a two-week period.

Cell-adhesiveness is key to many approaches in biomaterial research and tissue engineering. A step-by-step technique is presented using wet-chemistry for the surface modification of the important polymer PTFE with peptides.

الرطب الكيمياء والببتيد الشلل على تترافلوروإيثيلين لتحسين خلية التصاق

Endowing materials surface with cell-adhesive properties is a common strategy in biomaterial research and tissue engineering. This is particularly ...

3D Magnetic Stem Cell Aggregation and Bioreactor Maturation for Cartilage Regeneration

Cartilage engineering remains a challenge due to the difficulties in creating an in vitro functional implant similar to the native tissue. An approach recently explored for the development of autologous replacements involves the differentiation of stem cells into chondrocytes. To initiate this chondrogenesis, a degree of compaction of the stem cells is required; hence, we demonstrated the feasibility of magnetically condensing cells, both within thick scaffolds and scaffold-free, using miniaturized magnetic field sources as cell attractors. This magnetic approach was also used to guide aggregate fusion and to build scaffold-free, organized, three-dimensional (3D) tissues several millimeters in size. In addition to having an enhanced size, the tissue formed by magnetic-driven fusion presented a significant increase in the expression of collagen II, and a similar trend was observed for aggrecan expression. As the native cartilage was subjected to forces that influenced its 3D structure, dynamic maturation was also performed. A bioreactor that provides mechanical stimuli was used to culture the magnetically seeded scaffolds over a 21-day period. Bioreactor maturation largely improved chondrogenesis into the cellularized scaffolds; the extracellular matrix obtained under these conditions was rich in collagen II and aggrecan. This work outlines the innovative potential of magnetic condensation of labeled stem cells and dynamic maturation in a bioreactor for improved chondrogenic differentiation, both scaffold-free and within polysaccharide scaffolds.

Chondrogenesis from stem cells requires fine tuning the culture conditions. Here, we present a magnetic approach for condensing cells, an essential step to initiate chondrogenesis. In addition, we show that dynamic maturation in a bioreactor applies mechanical stimulation to the cellular constructs and enhances cartilaginous extracellular matrix production.

3D تجميع المغناطيسي الخلايا الجذعية ومفاعل حيوي النضج لتجديد الغضروف

Cartilage engineering remains a challenge due to the difficulties in creating an in vitro functional implant similar to the native tissue. An approach ...

Development of Microfluidic Devices to Study the Elongation Capability of Tip-growing Plant Cells in Extremely Small Spaces

In vivo, tip-growing plant cells need to overcome a series of physical barriers; however, researchers lack the methodology to visualize cellular behavior in such restrictive conditions. To address this issue, we have developed growth chambers for tip-growing plant cells that contain a series of narrow, micro-fabricated gaps (~1 &#181;m) in a poly-dimethylsiloxane (PDMS) substrate. This transparent material allows the user to monitor tip elongation processes in individual cells during microgap penetration by time-lapse imaging. Using this experimental platform, we observed morphological changes in pollen tubes as they penetrated the microgap. We captured the dynamic changes in the shape of a fluorescently labeled vegetative nucleus and sperm cells in a pollen tube during this process. Furthermore, we demonstrated the capability of root hairs and moss protonemata to penetrate the 1 &#181;m gap. This in vitro platform can be used to study how individual cells respond to physically constrained spaces and may provide insights into tip-growth mechanisms.

We describe a method to investigate the capability of tip-growing plant cells, including pollen tubes, root hairs, and moss protonemata, to elongate through extremely narrow gaps (~1 &#181;m) in a microfluidic device.

تطوير أجهزة موائع جزيئية لدراسة قدرة استطالة نصيحة زراعة الخلايا النباتية في المساحات الصغيرة للغاية

In vivo, tip-growing plant cells need to overcome a series of physical barriers; however, researchers lack the methodology to visualize cellular behavior ...

Detection of Endotoxin in Nano-formulations Using Limulus Amoebocyte Lysate (LAL) Assays

When present in pharmaceutical products, a Gram-negative bacterial cell wall component endotoxin (often also called lipopolysaccharide) can cause inflammation, fever, hypo- or hypertension, and, in extreme cases, can lead to tissue and organ damage that may become fatal. The amounts of endotoxin in pharmaceutical products, therefore, are strictly regulated. Among the methods available for endotoxin detection and quantification, the Limulus Amoebocyte Lysate (LAL) assay is commonly used worldwide. While any pharmaceutical product can interfere with the LAL assay, nano-formulations represent a particular challenge due to their complexity. The purpose of this paper is to provide a practical guide to researchers inexperienced in estimating endotoxins in engineered nanomaterials and nanoparticle-formulated drugs. Herein, practical recommendations for performing three LAL formats including turbidity, chromogenic and gel-clot assays are discussed. These assays can be used to determine endotoxin contamination in nanotechnology-based drug products, vaccines, and adjuvants.

Detection of Endotoxin in Nano-formulations Using Limulus Amoebocyte Lysate LAL Assays

Detection of endotoxins in engineered nanomaterials represents one of the grand challenges in the field of nanomedicine. Here, we present a case study that describes the framework composed of three different LAL formats to estimate potential endotoxin contamination in nanoparticles.

كشف الذيفان في تركيبات النانو باستخدام فحوصات ليستي (ال) أموبوسيتي ليمولوس

When present in pharmaceutical products, a Gram-negative bacterial cell wall component endotoxin (often also called lipopolysaccharide) can cause ...

A Multilayer Microfluidic Platform for the Conduction of Prolonged Cell-Free Gene Expression

The limitations of cell-based synthetic biology are becoming increasingly apparent as researchers aim to develop larger and more complex synthetic genetic regulatory circuits. The analysis of synthetic genetic regulatory networks in vivo is time consuming and suffers from a lack of environmental control, with exogenous synthetic components interacting with host processes resulting in undesired behavior. To overcome these issues, cell-free characterization of novel circuitry is becoming more prevalent. In vitro transcription and translation (IVTT) mixtures allow the regulation of the experimental environment and can be optimized for each unique system. The protocols presented here detail the fabrication of a multilayer microfluidic device that can be utilized to sustain IVTT reactions for prolonged durations. In contrast to batch reactions, where resources are depleted over time and (by-) products accumulate, the use of microfluidic devices allows the replenishment of resources as well as the removal of reaction products. In this manner, the cellular environment is emulated by maintaining an out-of-equilibrium environment in which the dynamic behavior of gene circuits can be investigated over extended periods of time. To fully exploit the multilayer microfluidic device, hardware and software have been integrated to automate the IVTT reactions. By combining IVTT reactions with the microfluidic platform presented here, it becomes possible to comprehensively analyze complex network behaviors, furthering our understanding of the mechanisms that regulate cellular processes.

The fabrication process of a PDMS-based, multilayer, microfluidic device that allows in vitro transcription and translation (IVTT) reactions to be performed over prolonged periods is described. Furthermore, a comprehensive overview of the hardware and software required to automate and maintain these reactions for prolonged durations is provided.

منصة ميكروفلويدريك متعددة الطبقات لتوصيل التعبير الجيني الخالي من الخلايا لفترات طويلة

The limitations of cell-based synthetic biology are becoming increasingly apparent as researchers aim to develop larger and more complex synthetic genetic ...

Fabrication of a Biomimetic Nano-Matrix with Janus Base Nanotubes and Fibronectin for Stem Cell Adhesion

A biomimetic NM was developed to serve as a tissue-engineering biological scaffold, which can enhance stem cell anchorage. The biomimetic NM is formed from JBNTs and FN through self-assembly in an aqueous solution. JBNTs measure 200-300 &#181;m in length with inner hydrophobic hollow channels and outer hydrophilic surfaces. JBNTs are positively charged and FNs are negatively charged. Therefore, when injected into a neutral aqueous solution, they are bonded together via noncovalent bonding to form the NM bundles. The self-assembly process is completed within a few seconds without any chemical initiators, heat source, or UV light. When the pH of the NM solution is lower than the isoelectric point of FNs (pI 5.5-6.0), the NM bundles will self-release due to the presence of positively charged FN.
NM is known to mimic the extracellular matrix (ECM) morphologically and hence, can be used as an injectable scaffold, which provides an excellent platform to enhance hMSC adhesion. Cell density analysis and fluorescence imaging experiments indicated that the NMs significantly increased the anchorage of hMSCs compared to the negative control.

The goal of this protocol is to show the assembly of a biomimetic nanomatrix (NM) with Janus base nanotubes (JBNTs) and fibronectin (FN). When co-cultured with human mesenchymal stem cells (hMSCs), the NMs exhibit excellent bioactivity in encouraging hMSCs adhesion.

تصنيع مصفوفة نانوية حيوية مع الأنابيب النانوية الأساسية يانوس وليفينيكتين للتصاق الخلايا الجذعية

A biomimetic NM was developed to serve as a tissue-engineering biological scaffold, which can enhance stem cell anchorage. The biomimetic NM is formed ...