We thank Dr. Oliver Kerscher for support and advice and members of the Basrai laboratory for their support and comments on the paper. This work was supported by the National Institutes of Health Intramural Research Program.

1. Crecimiento de células de levadura <ol><li> Inocular células de levadura en 30 ml de YPD (Tabla 1) en un matraz pequeño. Incubar a 30 ° C durante la noche con agitación. </li><li> Diluir las células a una densidad óptica de 0,2 a 600 nm (OD 600 = 0,2) en 50 ml de YPD y se incuba a 30 ° C con agitación. </li><li> Mantener el cultivo a una densidad óptica de 1,0 a 600 nm (OD 600 = 1,0). </li><li> Centrifugar las células durante 5 minutos a 2.000 xg y descartar el sobrenadante. </li><li> Resuspender el sedimento celular en 40 ml de agua estéril y centrifugar durante 5 min a 2000 xg para lavar las células. Descartar el sobrenadante y el sedimento celular almacenar a -20 ° C. </li></ol> 2. Extracción de Proteínas <ol><li> Resuspender las células en 0,5 ml de tampón enfriado con hielo de guanidina (Tabla 1) para el ensayo de pull-down usando perlas Superflow Ni-NTA o tampón A (Tabla 1) para la inmunoprecipitación. Mantenga los tubos en hielo en todo momento. </li><li> Transferencia a 2 ml tubo de tapón de rosca. </li><li> Añadir el mismo volumen de cuentas de vidrio (Tabla de Materiales). </li><li> Bolas de batir las células en un mini batidor grano (Tabla de Materiales) durante 2 minutos a temperatura ambiente, luego se coloca en hielo durante 2-3 minutos. Repita esto tres veces. </li><li> Vortex a velocidad alta a 4 ° C durante 30-60 minutos. Compruebe las células mediante visualización bajo el microscopio para asegurar que las células se lisan. Nota: Las células lisadas aparecerán fantasmas oscuros y carecen de un límite o forma definida. De manera óptima al menos 80% de las células debe ser lisadas. </li><li> Perforar un agujero en la parte inferior del tubo utilizando un alfiler y el lugar en una colección de 15 ml tubo cónico (tapón de rosca debe ser suelta). </li><li> Centrifugar a 1000 xg durante 1 min para recoger el lisado. </li><li> Transferir el lisado a un tubo de micro centrífuga. </li><li> Centrifugar a 15000 xg durante 30 min a 4 ° C para recoger las proteínas extraídas. </li><li> Medir la concentración de las proteínas extraídas mediante el assa proteínay kit (Tabla de Materiales) y normalizar todos los extractos para contener la misma cantidad de proteína. Llevar el volumen total a 1 ml con tampón apropiado. Nota: Alrededor de 5 mg de proteína total se obtiene de 50 OD 600 células. </li><li> Ahorre 50 l (g de proteína 250 si la proteína total extraído de paso 2,10 es 5 mg) en forma de extracto de células enteras (EBB). Añadir 50 l de tampón de muestra Laemmli 2x (Tabla 1) y se incuba a 100 ° C en un bloque de calor durante 3-5 min. Cargar 10 l de cada muestra en un gel de SDS-PAGE para el análisis de Western Blot (Sección 5: Western blot). </li></ol> 3. Purificación de HF-Smt3 conjugados <ol><li> Obtener las perlas Superflow Ni-NTA (Tabla de materiales) necesarios para los experimentos (100 l de granos por muestra) por centrifugación a baja velocidad (800-1,500 xg) durante 1 minuto. Eliminar el sobrenadante. </li><li> Lave las perlas de 5x con 1 ml de PBS (Tabla de Materiales): Invertir top-sobre-inferior hasta que se vuelven a suspender las cuentas, recoger perlas por centrifugación a baja velocidad, y retire el sobrenadante. </li><li> Suspender perlas en 1 ml de tampón de guanidina (Tabla 1) y alícuota ellos en el número de tubos correspondientes a las muestras para ser procesados. Recoger los granos mediante centrifugación a baja velocidad, y eliminar el sobrenadante. Mezclar los granos bien invirtiendo arriba sobre la parte inferior. Nota: Mezclar los granos bien invirtiendo bottom top-over. </li><li> Para cada muestra, añadir 950 l de la WCE restante (del Paso 2.11: Extracción de proteínas) a 100 l de perlas de Ni-NTA Superflow. </li><li> Incubar en una plataforma oscilante a 4 ° C durante al menos 4 horas o durante la noche. </li><li> Centrifugar a 800-1,500 xg durante 1 min a 4 ° C. </li><li> Ahorre 50 l como sobrenadante (SUP). Añadir 50 l de tampón de muestra Laemmli 2x y se incuba a 100 ° C en un bloque de calor durante 3-5 min. Cargar 10 l de cada muestra en un gel de SDS-PAGE para el análisis de Western Blot (Sección 5: anal Western blotanalysis). </li><li> Perlas Lavar una vez con 1 ml de tampón de guanidina para 5-10 minutos sobre una plataforma oscilante. </li><li> Lavar las perlas de 5x con 1 ml de tampón de ruptura (Tabla 1) durante 5-10 minutos en una plataforma oscilante. </li><li> Perlas de resuspender en 90 l de tampón de muestra Laemmli 2x. </li><li> Añadir 10 l de 1 M imidazol. Nota: imidazol ayuda a disociar la proteína marcada con His de las perlas de Ni-NTA debido a la interacción que compiten entre imidazol y las perlas. </li><li> Incubar a 100 ° C en un bloque de calor durante 3-5 minutos. </li><li> Vortex y centrifugar a 13.000 xg durante 30 seg. Transferir el sobrenadante a un tubo nuevo. </li><li> Cargar 10-20 l de cada muestra en un gel de SDS-PAGE para el análisis de Western Blot (Sección 5: Western blot). Nota: 10-20 l corresponde a 0,5-1,0 mg de entrada, si se utiliza 5 mg de WCE. </li></ol> 4. La inmunoprecipitación de etiquetado-Myc proteínas cinetocoro <ol><li> Obtener-c-Myc contra afinidad de agarosa un geltibody (Tabla de materiales) necesarios para los experimentos (25 l de resina por muestra) por centrifugación a baja velocidad (800-1,500 xg). Eliminar el sobrenadante. </li><li> Lave 5x resina con 1 ml de tampón A: top-sobre-fondo Invertir hasta que se volvió a suspender la resina, resina recogen por centrifugación a baja velocidad, y eliminar el sobrenadante. </li><li> Suspender resina en 1 ml de tampón A y alícuota ellos en el número de tubos correspondientes a las muestras para ser procesados. Recoger resina mediante centrifugación a baja velocidad, y eliminar el sobrenadante. Nota: Mezclar la resina bien invirtiendo top-sobre-fondo. </li><li> Añadir 950 l de la EBB restante (del Paso 2.11: La extracción de proteínas) a 25 l de resina. </li><li> Incubar en una plataforma oscilante a 4 ° C durante la noche. </li><li> Centrifugar a 800-1,500 xg durante 1 min a 4 ° C. </li><li> Ahorre 50 l como sobrenadante (SUP). Añadir 50 l de tampón de muestra Laemmli 2x y se incuba a 100 ° C en un bloque de calor durante 3-5 min. Load 10 l de cada muestra en un gel de SDS-PAGE para el análisis de Western Blot (Sección 5: Western blot). </li><li> Lave 5x resina con 1 ml de tampón A: top-sobre-fondo Invertir hasta que se volvió a suspender la resina, resina recogen por centrifugación a baja velocidad, y eliminar el sobrenadante. </li><li> Resuspender la resina en 100 l de tampón de muestra SUMEB (Tabla 1). Nota: tampón de muestra SUMEB contiene urea 8 M y SDS al 1% (fuerte condición de desnaturalización). </li><li> Incubar a 100 ° C en un bloque de calor durante 3-5 minutos. </li><li> Vortex y centrifugar a 13.000 xg durante 30 seg. Transferir el sobrenadante a un tubo nuevo. </li><li> Cargar 10-20 l de cada muestra en un gel de SDS-PAGE para el análisis de Western Blot (Sección 5: Western blot). Nota: 10-20 l corresponde a 0,5-1,0 mg de entrada, si se utiliza 5 mg de WCE. </li></ol> 5. Western Blot Analysis <ol><li> Cargue los extractos de proteínas de 4-12% Bis-Tris geles (Tabla de Materiales) y perfelectroforesis orm a 120 V durante 90 min (Ejecución de búfer: Tabla de Materiales). </li><li> Transferencia de las proteínas a partir de gel a una membrana de nitrocelulosa (Tabla de Materiales) usando un aparato de transferencia a 30 V durante 90 minutos (tampón de transferencia: Tabla de Materiales). </li><li> Bloquear la membrana en 5% leche / TBST 1x (Tabla 1) durante 1 hora a temperatura ambiente. </li><li> Incubar la membrana con el anticuerpo primario (Tabla de Materiales) en 5% de leche / 1x TBST durante la noche a 4 ° C. Para los anticuerpos primarios, utilizar una dilución de 1: 1000 (anticuerpos anti-Flag y anti-UB) o 1: 5000 (anticuerpo anti-Myc). </li><li> Lave 3x membrana durante 10 minutos cada uno con 1x TBST. </li><li> Incubar la membrana con el anticuerpo secundario (Tabla de Materiales) en 5% de leche / 1x TBST durante 1 hora a temperatura ambiente. Utilice una dilución 1: 5000 de anticuerpos secundarios. </li><li> Lave 3x membrana durante 10 minutos cada uno con 1x TBST. </li><li> Incubar la membrana con ECL workisolución ng (Tabla de Materiales) durante 5 min. </li><li> Exponer la membrana sensible al azul película de rayos X (Tabla de Materiales) y desarrollar el uso de un programador automático (Tabla de Materiales). </li></ol>

<ol>
	<li>Johnson, P. R., Hochstrasser, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=SUMO-1:+Ubiquitin+gains+weight.">SUMO-1: Ubiquitin gains weight.</a> Trends Cell Biol. 7, 408-413 (1997).</li><li>Hewawasam, G., 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=Psh1+is+an+E3+ubiquitin+ligase+that+targets+the+centromeric+histone+variant+Cse4.">Psh1 is an E3 ubiquitin ligase that targets the centromeric histone variant Cse4.</a> Mol Cell. 40, 444-454 (2010).</li><li>Ranjitkar, P., 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=An+E3+ubiquitin+ligase+prevents+ectopic+localization+of+the+centromeric+histone+H3+variant+via+the+centromere+targeting+domain.">An E3 ubiquitin ligase prevents ectopic localization of the centromeric histone H3 variant via the centromere targeting domain.</a> Mol Cell. 40, 455-464 (2010).</li><li>Au, W. C., 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=A+novel+role+of+the+N+terminus+of+budding+yeast+histone+H3+variant+Cse4+in+ubiquitin-mediated+proteolysis.">A novel role of the N terminus of budding yeast histone H3 variant Cse4 in ubiquitin-mediated proteolysis.</a> Genetics. 194, 513-518 (2013).</li><li>Akiyoshi, B., 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=The+Mub1/Ubr2+ubiquitin+ligase+complex+regulates+the+conserved+Dsn1+kinetochore+protein.">The Mub1/Ubr2 ubiquitin ligase complex regulates the conserved Dsn1 kinetochore protein.</a> PLoS Genet. 9, e1003216 (2013).</li><li>Biggins, 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=The+conserved+protein+kinase+Ipl1+regulates+microtubule+binding+to+kinetochores+in+budding+yeast.">The conserved protein kinase Ipl1 regulates microtubule binding to kinetochores in budding yeast.</a> Genes Dev. 13, 532-544 (1999).</li><li>Cheeseman, I. M., 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=Phospho-regulation+of+kinetochore-microtubule+attachments+by+the+Aurora+kinase+Ipl1p.">Phospho-regulation of kinetochore-microtubule attachments by the Aurora kinase Ipl1p.</a> Cell. 111, 163-172 (2002).</li><li>Liu, D., Lampson, M. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Regulation+of+kinetochore-microtubule+attachments+by+Aurora+B+kinase.">Regulation of kinetochore-microtubule attachments by Aurora B kinase.</a> Biochem Soc Trans. 37, 976-980 (2009).</li><li>Montpetit, B., Hazbun, T. R., Fields, S., Hieter, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sumoylation+of+the+budding+yeast+kinetochore+protein+Ndc10+is+required+for+Ndc10+spindle+localization+and+regulation+of+anaphase+spindle+elongation.">Sumoylation of the budding yeast kinetochore protein Ndc10 is required for Ndc10 spindle localization and regulation of anaphase spindle elongation.</a> J Cell Biol. 174, 653-663 (2006).</li><li>Furth, N., 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=Exposure+of+bipartite+hydrophobic+signal+triggers+nuclear+quality+control+of+Ndc10+at+the+endoplasmic+reticulum/nuclear+envelope.">Exposure of bipartite hydrophobic signal triggers nuclear quality control of Ndc10 at the endoplasmic reticulum/nuclear envelope.</a> Mol Biol Cell. 22, 4726-4739 (2011).</li><li>Li, L., 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=Anaphase-promoting+complex/cyclosome+controls+HEC1+stability.">Anaphase-promoting complex/cyclosome controls HEC1 stability.</a> Cell Prolif. 44, 1-9 (2011).</li><li>Takahashi, Y., Yong-Gonzalez, V., Kikuchi, Y., Strunnikov, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=SIZ1/SIZ2+control+of+chromosome+transmission+fidelity+is+mediated+by+the+sumoylation+of+topoisomerase+II.">SIZ1/SIZ2 control of chromosome transmission fidelity is mediated by the sumoylation of topoisomerase II.</a> Genetics. 172, 783-794 (2006).</li><li>Liu, C., Apodaca, J., Davis, L. E., Rao, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Proteasome+inhibition+in+wild-type+yeast+Saccharomyces+cerevisiae+cells.">Proteasome inhibition in wild-type yeast Saccharomyces cerevisiae cells.</a> Biotechniques. 42, 158 (2007).</li><li>Kitamura, E., Tanaka, K., Kitamura, Y., Tanaka, T. U. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Kinetochore+microtubule+interaction+during+S+phase+in+Saccharomyces+cerevisiae.">Kinetochore microtubule interaction during S phase in Saccharomyces cerevisiae.</a> Genes Dev. 21, 3319-3330 (2007).</li><li>Gascoigne, K. E., Cheeseman, I. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Kinetochore+assembly:+if+you+build+it,+they+will+come.">Kinetochore assembly: if you build it, they will come.</a> Curr Opin Cell Biol. 23, 102-108 (2011).</li></ol>

The authors have nothing to disclose.

Etiquetas de epítopo tales como HA, Myc, Flag, GST y son ampliamente utilizados para el análisis bioquímico de las proteínas. Construcción de cepas con HF-Smt3 y kinetochore proteínas etiquetadas-Myc, tales como Ndc10 y Ndc80, facilita la detección de PTM tales como sumoylation y ubiquitinación. HF-Smt3 desplegable ensayo permite la detección de proteínas cinetocoro sumoylated, Ndc10 y Ndc80 (Figura 1). El protocolo de purificación por afinidad y análisis de transferencia Western usando anti...

La ubiquitinación y la sumoilación permiten la conjugación de la ubiquitina y el modificador Pequeño ubiquitina-like (SUMO; Smt3 en S. cerevisiae 1) a una proteína diana, respectivamente. PTMs de proteínas kinetochore afectan a sus niveles celulares y las interacciones proteína-proteína durante las diferentes fases del ciclo celular para asegurar la segregación cromosómica fiel. Por ejemplo, los niveles celulares de Cse4 / CENP-A y proteínas cinetocoro externo DSN1 están regulados por la proteólisis mediada por ubiquitina de asegurar la estabilidad del genoma 2-5. La desestabilización de accesorios-cinetocoro microtúbulos incorrectas requiere la quinasa B Ipl1 / Aurora, que fosforila Dam1 y Ndc80 complejos que interactúan directamente con los microtúbulos 6-8. A pesar de la identificación de más de setenta proteínas cinetocoro, hay muy pocos estudios que investiguen las modificaciones de estas proteínas con PTM, por ejemplo, ubiquitina y SUMO. Una limitación importante es la capacidad de preservar la PTMs durante la purificación y la escasez de anticuerpos personalizados para la detección de PTM tales como sumoylation, fosforilación, metilación, y otros. Caracterización de proteínas cinetocoro sumoylated Ndc10, Cep3, Bir1 y Ndc80 utiliza un anticuerpo encargo 9. Además, Ndc10 ha sido implicado como un sustrato para la ubiquitinación 10. Hec1 Humano (Ndc80 en S. cerevisiae) también está sustrato para la ubiquitinación, regulado por APC / C-hCdh1 E3 ligasa 11. Por lo tanto, Ndc10 y Ndc80 son buenos candidatos para la optimización del protocolo para detectar tanto sumoylation y ubiquitinación en S. cerevisiae. Para facilitar la identificación de sumoylation, construimos cepas que expresan HF-Smt3 y etiquetada-Myc Ndc10 o Ndc80. El uso de etiquetas de epítopo (HF: His6-Flag) minimiza el fondo debido a la reactividad cruzada que se observa frecuentemente en el suero policlonal generado contra una proteína candidato. Hemos elaborado un protocolo de afinidadpurificar conjugados de HF-Smt3 y luego se usa anticuerpos anti-myc anti-Flag y comercial para detectar la presencia de sumolyated Ndc10 y Ndc80 en la preparación Smt3 purificado. Para ubiquitinación, ideamos un protocolo de inmunoprecipitación modificada que conserva la ubiquitinación de las proteínas del cinetocoro Myc-etiquetados y realizó el análisis de Western blot con el anticuerpo anti-Ub comercial para detectar la ubiquitinación de Ndc10 y Ndc80.

<table border="0" cellpadding="0" cellspacing="0">
	<tbody>
		<tr>
			<td>Glass beads</td>
			<td>BioSpec Products</td>
			<td align="right">11079105</td>
			<td>0.5 mm dia.</td>
		</tr>
		<tr>
			<td>Mini beadbeater</td>
			<td>BioSpec Products</td>
			<td>#693</td>
			<td>8 cell disrupter</td>
		</tr>
		<tr>
			<td>Ni-NTA superflow</td>
			<td>Qiagen</td>
			<td align="right">30430</td>
			<td>100 ml</td>
		</tr>
		<tr>
			<td>Protease inhibitor cocktail</td>
			<td>Sigma-Aldrich</td>
			<td>P8215</td>
			<td>1 ml</td>
		</tr>
		<tr>
			<td>Anti-c-Myc agarose affinity gel antbody produced in rabbit</td>
			<td>Sigma-Aldrich</td>
			<td>A7470</td>
			<td>1 ml</td>
		</tr>
		<tr>
			<td>Monoclonal anti-Flag M2 antibody produced in mouse</td>
			<td>Sigma-Aldrich</td>
			<td>F1804</td>
			<td>Primary antibody, dilution 1:1000</td>
		</tr>
		<tr>
			<td>c-Myc antibody (A-14)</td>
			<td>Santa Cruz Biotechnology</td>
			<td>sc-789</td>
			<td>Primary antibody, dilution 1:5000</td>
		</tr>
		<tr>
			<td>Purified mouse antibody monoclonal 9E10</td>
			<td>Covance</td>
			<td>MMS-150P</td>
			<td>Primary antibody, dilution 1:5000</td>
		</tr>
		<tr>
			<td>Ubiquitin (P4G7) monoclonal antibody</td>
			<td>Covance</td>
			<td>MMS-258R</td>
			<td>Primary antibody, dilution 1:1000</td>
		</tr>
		<tr>
			<td>ECL Rabbit IgG, HRP-linked whole Ab</td>
			<td>GE Healthcare Life Sciences</td>
			<td>NA934V</td>
			<td>Secondary antibody, dilution 1:5000</td>
		</tr>
		<tr>
			<td>ECL Mouse IgG, HRP-Linked Whole Ab</td>
			<td>GE Healthcare Life Sciences</td>
			<td>NA931V</td>
			<td>Secondary antibody, dilution 1:5000</td>
		</tr>
		<tr>
			<td>DC protein assay</td>
			<td>Bio-Rad</td>
			<td>500-0116</td>
			<td></td>
		</tr>
		<tr>
			<td>Nitrocellulose membrane</td>
			<td>Novex</td>
			<td>LC2001</td>
			<td>0.45 mm pore size</td>
		</tr>
		<tr>
			<td>NuPAGE 4-12% Bis-Tris Protein Gels</td>
			<td>Novex</td>
			<td>NP0321BOX</td>
			<td>1.0 mm, 10 well</td>
		</tr>
		<tr>
			<td>NuPAGE MES SDS Running Buffer</td>
			<td>Novex</td>
			<td>NP0002</td>
			<td>20x</td>
		</tr>
		<tr>
			<td>NuPAGE Transfer Buffer</td>
			<td>Novex</td>
			<td>NP0006-1</td>
			<td>20x</td>
		</tr>
		<tr>
			<td>SuperSignal West Pico Chemiluminescent Substrate</td>
			<td>Thermo Scientific</td>
			<td align="right">34078</td>
			<td></td>
		</tr>
		<tr>
			<td>10x PBS pH7.4</td>
			<td>GIBCO</td>
			<td>70011-044</td>
			<td></td>
		</tr>
		<tr>
			<td>Blue sensitive X-Ray film</td>
			<td>Dbio</td>
			<td>DBOF30003</td>
			<td></td>
		</tr>
		<tr>
			<td>Automatic developer</td>
			<td>Kodak</td>
			<td>M35AX-OMAT</td>
			<td></td>
		</tr>
		<tr>
			<td>Nocodazole</td>
			<td>Sigma-Aldrich</td>
			<td>M1404</td>
			<td>50 mg</td>
		</tr>
		<tr>
			<td>MG-132</td>
			<td>Selleck Chemicals</td>
			<td>S2619</td>
			<td>25 mg</td>
		</tr>
	</tbody>
</table>

protein purification technique that allows detection of sumoylation and ubiquitination of budding yeast kinetochore proteins ndc10 and ndc80

Modificaciones post-traduccionales (PTMs), tales como fosforilación, metilación, acetilación, ubiquitinación, y sumoylation, regulan la función celular de muchas proteínas. PTM de proteínas cinetocoro que se asocian con el ADN centromérico median segregación cromosómica fieles a mantener la estabilidad del genoma. Enfoques bioquímicos como la espectrometría de masas y análisis de transferencia Western son los más utilizados para la identificación de los PTM. Aquí, un método de purificación de proteínas se describe que permite la detección de tanto sumoylation y ubiquitinación de las proteínas del cinetocoro, Ndc10 y Ndc80, en Saccharomyces cerevisiae. Una cepa que expresa etiquetados-polihistidina-Bandera Smt3 (HF-Smt3) y Myc-etiquetados Ndc10 o Ndc80 fue construido y utilizado para nuestros estudios. Para la detección de sumoylation, ideamos un protocolo para purificar por afinidad proteínas sumoylated etiquetados-Su usando perlas de níquel y utilizamos Western blot con anti-Myc anticuerpos para detectar sumoylated Ndc10 unnd Ndc80. Para la detección de ubiquitinación, ideamos un protocolo de inmunoprecipitación de proteínas Myc-etiquetados y utilizamos Western blot con el anticuerpo anti-Ub para demostrar que Ndc10 y Ndc80 se ubiquitinated. Nuestros resultados muestran que el epítopo de etiquetado proteína de interés en el Su-Bandera etiquetado cepa Smt3 facilita la detección de múltiples PTM. Los estudios futuros deben permitir la explotación de esta técnica para identificar y caracterizar las interacciones de proteínas que son dependientes de un PTM específico.

Para detectar sumoylation de proteínas cinetocoro Ndc80 y Ndc10, cepas con HF-Smt3 y proteínas cinetocoro etiquetados-Myc (Ndc80 o Ndc10) fueron construidos (Tabla 2), como se describió anteriormente 9,12. Conjugados HF-Smt3 fueron purificados por afinidad utilizando perlas de Ni-NTA. Western blot de purificado HF-Smt3 con un permitido la detección de anticuerpos anti-Bandera de formas sumoylated de sustratos SUMO que en la cepa control sin HF-Smt3 (Figura 1A y 1B...

Watch this Scientific Journal Video about Protein Purification Technique that Allows Detection of Sumoylation and Ubiquitination of Budding Yeast Kinetochore Proteins Ndc10 and Ndc80 at JoVE.com

Protein Purification Technique that Allows Detection of Sumoylation and Ubiquitination of Budding Yeast Kinetochore Proteins Ndc10 and Ndc80

Este manuscrito describe la detección de sumoylation y ubiquitinación de proteínas del cinetocoro, Ndc10 y Ndc80, en la levadura Saccharomyces cerevisiae en ciernes.

Proteína técnica de purificación que permite la detección de Sumoylation y Ubiquitination de levadura en ciernes cinetocoro Proteínas Ndc10 y Ndc80

Post-translational Modifications (PTMs), such as phosphorylation, methylation, acetylation, ubiquitination, and sumoylation, regulate the cellular ...

protein-purification-technique-that-allows-detection-sumoylation

Research

JoVE Journal

Biology

12.0K vistas.  National Cancer Institute, National Institute of Health.  Este manuscrito describe la detección de sumoylation y ubiquitinación de proteínas del cinetocoro, Ndc10 y Ndc80, en la levadura Saccharomyces cerevisiae en ciernes. 

Video: Protein Purification Technique that Allows Detection of Sumoylation and Ubiquitination of Budding Yeast Kinetochore Proteins Ndc10 and Ndc80

Measuring Replicative Life Span in the Budding Yeast

Aging is a degenerative process characterized by a progressive deterioration of cellular components and organelles resulting in mortality. The budding yeast Saccharomyces cerevisiae has been used extensively to study the biology of aging, and several determinants of yeast longevity have been shown to be conserved in multicellular eukaryotes, including worms, flies, and mice 1. Due to the lack of easily quantified age-associated phenotypes, aging in yeast has been assayed almost exclusively by measuring the life span of cells in different contexts, with two different life span paradigms in common usage 2. Chronological life span refers to the length of time that a mother cell can survive in a non-dividing, quiescence-like state, and is proposed to serve as a model for aging of post-mitotic cells in multicellular eukaryotes. Replicative life span, in contrast, refers the number of daughter cells produced by a mother cell prior to senescence, and is thought to provide a model of aging in mitotically active cells. Here we present a generalized protocol for measuring the replicative life span of budding yeast mother cells. The goal of the replicative life span assay is to determine how many times each mother cell buds. The mother and daughter cells can be easily differentiated by an experienced researcher using a standard light microscope (total magnification 160X), such as the Zeiss Axioscope 40 or another comparable model. Physical separation of daughter cells from mother cells is achieved using a manual micromanipulator equipped with a fiber-optic needle. Typical laboratory yeast strains produce 20-30 daughter cells per mother and one life span experiment requires 2-3 weeks.

In this article we present a general protocol for measuring the replicative life span of yeast mother cells.

Medición de Span replicativa vida en la levadura en ciernes

Aging is a degenerative process characterized by a progressive deterioration of cellular components and organelles resulting in mortality. The budding ...

Investigación

Biología

Detection of Protein Ubiquitination

Ubiquitination, the covalent attachment of the polypeptide ubiquitin to target proteins, is a key posttranslational modification carried out by a set of three enzymes. They include ubiquitin-activating enzyme E1, ubiquitin-conjugating enzyme E2, and ubiquitin ligase E3. Unlike to E1 and E2, E3 ubiquitin ligases display substrate specificity. On the other hand, numerous deubiquitylating enzymes have roles in processing polyubiquitinated proteins. Ubiquitination can result in change of protein stability, cellular localization, and biological activity. Mutations of genes involved in the ubiquitination/deubiquitination pathway or altered ubiquitin system function are associated with many different human diseases such as various types of cancer, neurodegeneration, and metabolic disorders. The detection of altered or normal ubiquitination of target proteins may provide a better understanding on the pathogenesis of these diseases. &nbsp;Here, we describe protocols to detect protein ubiquitination in cultured cells in vivo and test tubes in vitro. These protocols are also useful to detect other ubiquitin-like small molecule modification such as sumolyation and neddylation.

Ubiquitination is a key posttranslational modification carried out by a set of three enzymes. Mutations of genes involved in this modification are associated with many different human diseases. Here, we describe protocols to detect protein ubiquitination in cultured cells in vivo and test tubes in vitro.

La detección de ubiquitinación de proteínas

Ubiquitination, the covalent attachment of the polypeptide ubiquitin to target proteins, is a key posttranslational modification carried out by a set of ...

Staining of Proteins in Gels with Coomassie G-250 without Organic Solvent and Acetic Acid

In classical protein staining protocols using Coomassie Brilliant Blue (CBB), solutions with high contents of toxic and flammable organic solvents (Methanol, Ethanol or 2-Propanol) and acetic acid are used for fixation, staining and destaining of proteins in a gel after SDS-PAGE. To speed up the procedure, heating the staining solution in the microwave oven for a short time is frequently used. This usually results in evaporation of toxic or hazardous Methanol, Ethanol or 2-Propanol and a strong smell of acetic acid in the lab which should be avoided due to safety considerations. In a protocol originally published in two patent applications by E.M. Wondrak (US2001046709 (A1), US6319720 (B1)), an alternative composition of the staining solution is described in which no organic solvent or acid is used. The CBB is dissolved in bidistilled water (60-80mg of CBB G-250 per liter) and 35 mM HCl is added as the only other compound in the staining solution. The CBB staning of the gel is done after SDS-PAGE and thorough washing of the gel in bidistilled water. By heating the gel during the washing and staining steps, the process can be finished faster and no toxic or hazardous compunds are evaporating. The staining of proteins occurs already within 1 minute after heating the gel in staining solution and is fully developed after 15-30 min with a slightly blue background that is destained completely by prolonged washing of the stained gel in bidistilled water, without affecting the stained protein bands.

A short protocol for protein staining with Coomassie Brilliant Blue (CBB) G-250 in polyacrylamide gels is described without using organic solvents or acetic acid as in the classical staining procedures with CBB.

Tinción de las proteínas en geles con Coomassie G-250, sin ácido disolvente orgánico y el acético

In classical protein staining protocols using Coomassie Brilliant Blue (CBB), solutions with high contents of toxic and flammable organic solvents ...

Purification of Mitochondria from Yeast Cells

Mitochondria are the main site of ATP production during aerobic metabolism in eukaryotic non-photosynthetic cells1. These complex organelles also play essential roles in apoptotic cell death2, cell survival3, mammalian development4, neuronal development and function4, intracellular signalling5, and longevity regulation6. Our understanding of these complex biological processes controlled by mitochondria relies on robust methods for assessing their morphology, their protein and lipid composition, the integrity of their DNA, and their numerous vital functions. The budding yeast Saccharomyces cerevisiae, a genetically and biochemically manipulable unicellular eukaryote with annotated genome and well-defined proteome, is a valuable model for studying the molecular and cellular mechanisms underlying essential biological functions of mitochondria. For these types of studies, it is crucial to have highly pure mitochondria. Here we present a detailed description of a rapid and effective method for purification of yeast mitochondria. This method enables the isolation of highly pure mitochondria that are essentially free of contamination by other organelles and retain their structural and functional integrity after their purification. Mitochondria purified by this method are suitable for cell-free reconstitution of essential mitochondrial processes and can be used for the analysis of mitochondrial structure and functions, mitochondrial proteome and lipidome, and mitochondrial DNA.

We describe a rapid and effective method for purification of mitochondria from the yeast Saccharomyces cerevisiae. This method enables the high-yield isolation of pure mitochondria that are essentially free of contamination by other organelles and retain their structural and functional integrity after their purification.

Purificación de las mitocondrias de las células de levadura

Mitochondria are the main site of ATP production during aerobic metabolism in eukaryotic non-photosynthetic cells1. These complex organelles also play ...

Analysis of the Development of a Morphological Phenotype as a Function of Protein Concentration in Budding Yeast

Gene deletion and protein overexpression are common methods for studying functions of proteins. In this article, we describe a protocol for analysis of phenotype development as a function of protein concentration at population and single-cell levels in Saccharomyces cerevisiae. Although this protocol is based on the overexpression of a protein, it can easily be adapted for morphological phenotypes dependent on suppression of protein expression. Our lab is interested in studying the signaling properties of the endocytic adaptor protein epsin. To that purpose we used a dominant negative approach in which we over-expressed the conserved Epsin N-Terminal Homology (ENTH) domain in order to interfere with the functions of endogenous epsin-2 (Ent2 or YLR206W). We observed that overexpression of the ENTH domain of Ent2 (ENTH2) in wild type cells led to a cell division defect that is dependent on the mislocalization of a family of scaffolding proteins, septins.

Gene deletion and protein overexpression are common methods for studying functions of proteins. In this article, we describe a protocol for analysis of phenotype development as a function of protein concentration at population and single-cell levels in Saccharomyces cerevisiae.

Análisis de la elaboración de un fenotipo morfológico en función de la concentración de proteínas en la levadura en ciernes

Gene deletion and protein overexpression are common methods for studying functions of proteins. In this article, we describe a protocol for analysis of ...

Purification of Hsp104, a Protein Disaggregase

Hsp104 is a hexameric AAA+ protein1 from yeast, which couples ATP hydrolysis to protein disaggregation2-10 (Fig. 1). This activity imparts two key selective advantages. First, renaturation of disordered aggregates by Hsp104 empowers yeast survival after various protein-misfolding stresses, including heat shock3,5,11,12. Second, remodeling of cross-beta amyloid fibrils by Hsp104 enables yeast to exploit myriad prions (infectious amyloids) as a reservoir of beneficial and heritable phenotypic variation13-22. Remarkably, Hsp104 directly remodels preamyloid oligomers and amyloid fibrils, including those comprised of the yeast prion proteins Sup35 and Ure223-30. This amyloid-remodeling functionality is a specialized facet of yeast Hsp104. The E. coli orthologue, ClpB, fails to remodel preamyloid oligomers or amyloid fibrils26,31,32.
Hsp104 orthologues are found in all kingdoms of life except, perplexingly, animals. Indeed, whether animal cells possess any enzymatic system that couples protein disaggregation to renaturation (rather than degradation) remains unknown33-35. Thus, we and others have proposed that Hsp104 might be developed as a therapeutic agent for various neurodegenerative diseases connected with the misfolding of specific proteins into toxic preamyloid oligomers and amyloid fibrils4,7,23,36-38. There are no treatments that directly target the aggregated species associated with these diseases. Yet, Hsp104 dissolves toxic oligomers and amyloid fibrils composed of alpha-synuclein, which are connected with Parkinson's Disease23 as well as amyloid forms of PrP39. Importantly, Hsp104 reduces protein aggregation and ameliorates neurodegeneration in rodent models of Parkinson's Disease23 and Huntington's disease38. Ideally, to optimize therapy and minimize side effects, Hsp104 would be engineered and potentiated to selectively remodel specific aggregates central to the disease in question4,7. However, the limited structural and mechanistic understanding of how Hsp104 disaggregates such a diverse repertoire of aggregated structures and unrelated proteins frustrates these endeavors30,40-42.
To understand the structure and mechanism of Hsp104, it is essential to study the pure protein and reconstitute its disaggregase activity with minimal components. Hsp104 is a 102kDa protein with a pI of ~5.3, which hexamerizes in the presence of ADP or ATP, or at high protein concentrations in the absence of nucleotide43-46. Here, we describe an optimized protocol for the purification of highly active, stable Hsp104 from E. coli. The use of E. coli allows simplified large-scale production and our method can be performed quickly and reliably for numerous Hsp104 variants. Our protocol increases Hsp104 purity and simplifies His6-tag removal compared to a previous purification method from E. coli47. Moreover, our protocol is more facile and convenient than two more recent protocols26,48.

Here, we describe a protocol for the purification of highly active Hsp104, a hexameric AAA+ protein from yeast, which couples ATP hydrolysis to protein disaggregation. This scheme exploits a His6-tagged construct for affinity purification from E. coli followed by anion-exchange chromatography, His6-tag removal with TEV protease, and size-exclusion chromatography.

La purificación de Hsp104, una proteína Disaggregase

Hsp104 is a hexameric AAA+ protein1 from yeast, which couples ATP hydrolysis to protein disaggregation2-10 (Fig. 1). This activity imparts two key ...

Chromatographic Purification of Highly Active Yeast Ribosomes

Eukaryotic ribosomes are much more labile as compared to their eubacterial and archael counterparts, thus posing a significant challenge to researchers. Particularly troublesome is the fact that lysis of cells releases a large number of proteases and nucleases which can degrade ribosomes. Thus, it is important to separate ribosomes from these enzymes as quickly as possible. Unfortunately, conventional differential ultracentrifugation methods leaves ribosomes exposed to these enzymes for unacceptably long periods of time, impacting their structural integrity and functionality. To address this problem, we utilize a chromatographic method using a cysteine charged Sulfolink resin. This simple and rapid application significantly reduces co-purifying proteolytic and nucleolytic activities, producing high yields of intact, highly biochemically active yeast ribosomes. We suggest that this method should also be applicable to mammalian ribosomes. The simplicity of the method, and the enhanced purity and activity of chromatographically purified ribosome represents a significant technical advancement for the study of eukaryotic ribosomes.

Contamination of preparations of eukaryotic ribosomes purified by traditional methods by co-purifying nucleases and proteases negatively impacts on downstream biochemical and structural analyses. A rapid and simple chromatographic purification method is used to solve this problem using yeast ribosomes as a model system.

Purificación por cromatografía de ribosomas de levadura de gran actividad

Eukaryotic ribosomes are much more labile as compared to their eubacterial and archael counterparts, thus posing a significant challenge to researchers.  ...

Acquiring Fluorescence Time-lapse Movies of Budding Yeast and Analyzing Single-cell Dynamics using GRAFTS

Fluorescence time-lapse microscopy has become a powerful tool in the study of many biological processes at the single-cell level. In particular, movies depicting the temporal dependence of gene expression provide insight into the dynamics of its regulation; however, there are many technical challenges to obtaining and analyzing fluorescence movies of single cells. We describe here a simple protocol using a commercially available microfluidic culture device to generate such data, and a MATLAB-based, graphical user interface (GUI) -based software package to quantify the fluorescence images. The software segments and tracks cells, enables the user to visually curate errors in the data, and automatically assigns lineage and division times. The GUI further analyzes the time series to produce whole cell traces as well as their first and second time derivatives. While the software was designed for S. cerevisiae, its modularity and versatility should allow it to serve as a platform for studying other cell types with few modifications.

We present a simple protocol to obtain fluorescence microscopy movies of growing yeast cells, and a GUI-based software package to extract single-cell time series data. The analysis includes automated lineage and division time assignment integrated with visual inspection and manual curation of tracked data.

La adquisición de fluorescencia Time-lapse películas de levadura en ciernes y el análisis de la dinámica de una sola célula con injertos

Fluorescence time-lapse microscopy has become a powerful tool in the study of many biological processes at the single-cell level. In particular, movies ...

Budding Yeast Protein Extraction and Purification for the Study of Function, Interactions, and Post-translational Modifications

Homogenization by bead beating is a fast and efficient way to release DNA, RNA, proteins, and metabolites from budding yeast cells, which are notoriously hard to disrupt. Here we describe the use of a bead mill homogenizer for the extraction of proteins into buffers optimized to maintain the functions, interactions and post-translational modifications of proteins. Logarithmically growing cells expressing the protein of interest are grown in a liquid growth media of choice. The growth media may be supplemented with reagents to induce protein expression from inducible promoters (e.g. galactose), synchronize cell cycle stage (e.g. nocodazole), or inhibit proteasome function (e.g. MG132). Cells are then pelleted and resuspended in a suitable buffer containing protease and/or phosphatase inhibitors and are either processed immediately or frozen in liquid nitrogen for later use. Homogenization is accomplished by six cycles of 20 sec&#160;bead-beating (5.5 m/sec), each followed by one minute incubation on ice. The resulting homogenate is cleared by centrifugation and small particulates can be removed by filtration. The resulting cleared whole cell extract (WCE) is precipitated using 20% TCA for direct analysis of total proteins by SDS-PAGE followed by Western blotting. Extracts are also suitable for affinity purification of specific proteins, the detection of post-translational modifications, or the analysis of co-purifying proteins. As is the case for most protein purification protocols, some enzymes and proteins may require unique conditions or buffer compositions for their purification and others may be unstable or insoluble under the conditions stated. In the latter case, the protocol presented may provide a useful starting point to empirically determine the best bead-beating strategy for protein extraction and purification. We show the extraction and purification of an epitope-tagged SUMO E3 ligase, Siz1, a cell cycle regulated protein that becomes both sumoylated and phosphorylated, as well as a SUMO-targeted ubiquitin ligase subunit, Slx5.

The preparation of high quality yeast cell extracts is a necessary first step in the analysis of individual proteins or entire proteomes. Here we describe a fast, efficient, and reliable homogenization protocol for budding yeast cells that has been optimized to preserve protein functions, interactions, and post-translational modifications.

Florecimiento extracción de proteínas de levadura y purificación para el Estudio de la función, las interacciones y modificaciones post-traduccionales

Homogenization by bead beating is a fast and efficient way to release DNA, RNA, proteins, and metabolites from budding yeast cells, which are notoriously ...

Green Fluorescent Protein-based Expression Screening of Membrane Proteins in Escherichia coli

The production of recombinant membrane proteins for structural and functional studies remains technically challenging due to low levels of expression and the inherent instability of many membrane proteins once solubilized in detergents. A protocol is described that combines ligation independent cloning of membrane proteins as GFP fusions with expression in Escherichia coli detected by GFP fluorescence. This enables the construction and expression screening of multiple membrane protein/variants to identify candidates suitable for further investment of time and effort. The GFP reporter is used in a primary screen of expression by visualizing GFP fluorescence following SDS polyacrylamide gel electrophoresis (SDS-PAGE). Membrane proteins that show both a high expression level with minimum degradation as indicated by the absence of free GFP, are selected for a secondary screen. These constructs are scaled and a total membrane fraction prepared and solubilized in four different detergents. Following ultracentrifugation to remove detergent-insoluble material, lysates are analyzed by fluorescence detection size exclusion chromatography (FSEC). Monitoring the size exclusion profile by GFP fluorescence provides information about the mono-dispersity and integrity of the membrane proteins in different detergents. Protein: detergent combinations that elute with a symmetrical peak with little or no free GFP and minimum aggregation are candidates for subsequent purification. Using the above methodology, the heterologous expression in E. coli of SED (shape, elongation, division, and sporulation) proteins from 47 different species of bacteria was analyzed. These proteins typically have ten transmembrane domains and are essential for cell division. The results show that the production of the SEDs orthologues in E. coli was highly variable with respect to the expression levels and integrity of the GFP fusion proteins. The experiment identified a subset for further investigation.

Green Fluorescent Protein-based Expression Screening of Membrane Proteins in Escherichia coli

A streamlined approach to screening for the expression of recombinant membrane proteins in Escherichia coli based on fusion to green fluorescent protein is presented.

Fluorescente verde a base de proteína Expresión Proyección de proteínas de membrana en<em&gt; Escherichia coli</em

The production of recombinant membrane proteins for structural and functional studies remains technically challenging due to low levels of expression and ...