The authors would like to thank Dr. Hui Zheng (Baylor College of Medicine) for the APP cDNA. This work was funded by NIH grants R21AG031948 (D.B., J.M.B.), F30AG030878 (E.S.S.), R01DK073394 (AFO), the John Sealy Memorial Endowment Fund for Biomedical Research (AFO), and the Jean C. and William D. Willis Neuroscience Research Endowment (E.S.S.). J.M.B. is a scholar in the Translational Research Scholar Program and a member of the University Of Texas Medical Branch Claude E. Pepper Older Americans Independence Center (supported by NIH Grants UL1RR029876 and P30-AG-024832, respectively).

1. Expression of Recombinant APP Intracellular Domain (AICD)
<ol>
 <li>Transform E. coli strain BL21 with human AICD (residues 649-695 of APP, neuronal isoform numbering) cloned into vector pGEX-4T-1 (GE Healthcare). This vector will express AICD as the C-terminal moiety of a fusion protein of glutathione-S-transferase (GST). This vector also encodes a thrombin cleavage sequence to facilitate removal of the GST moiety. Details of cloning AICD into pGEX-4T-1 can be found in our previous publication4....

<ol>
	<li>De Strooper, B., Vassar, R., Golde, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+secretases:+enzymes+with+therapeutic+potential+in+Alzheimer+disease.">The secretases: enzymes with therapeutic potential in Alzheimer disease.</a> Nature reviews. Neurology. 6, 99-107 (2010).</li><li>Chang, K. A., Suh, Y. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Possible+roles+of+amyloid+intracellular+domain+of+amyloid+precursor+protein.">Possible roles of amyloid intracellular domain of amyloid precursor protein.</a> BMB reports. 43, 656-663 (2010).</li><li>McLoughlin, D. M., Miller, C. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+FE65+proteins+and+Alzheimer's+disease.">The FE65 proteins and Alzheimer's disease.</a> J. Neurosci. Res. 86, 744-754 (2008).</li><li>Stieren, E. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ubiquilin-1+is+a+molecular+chaperone+for+the+amyloid+precursor+protein.">Ubiquilin-1 is a molecular chaperone for the amyloid precursor protein.</a> J. Biol. Chem. 286, 35689-35698 (2011).</li><li>Ramelot, T. A., Nicholson, L. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Phosphorylation-induced+structural+changes+in+the+amyloid+precursor+protein+cytoplasmic+tail+detected+by+NMR.">Phosphorylation-induced structural changes in the amyloid precursor protein cytoplasmic tail detected by NMR.</a> J. Mol. Biol. 307, 871-884 (2001).</li><li>Ramelot, T. A., Gentile, L. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Transient+structure+of+the+amyloid+precursor+protein+cytoplasmic+tail+indicates+preordering+of+structure+for+binding+to+cytosolic+factors.">Transient structure of the amyloid precursor protein cytoplasmic tail indicates preordering of structure for binding to cytosolic factors.</a> Biochem. 39, 2714-2725 (2000).</li><li>Radzimanowski, J. <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+intracellular+domain+of+the+amyloid+precursor+protein+in+complex+with+Fe65-PTB2.">Structure of the intracellular domain of the amyloid precursor protein in complex with Fe65-PTB2.</a> EMBO Rep. 9, 1134-1140 (2008).</li><li>Ohkawara, T., Nagase, H., Koh, C. S., Nakayama, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+amyloid+precursor+protein+intracellular+domain+alters+gene+expression+and+induces+neuron-specific+apoptosis.">The amyloid precursor protein intracellular domain alters gene expression and induces neuron-specific apoptosis.</a> Gene. 475, 1-9 (2011).</li><li>von Rotz, R. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+APP+intracellular+domain+forms+nuclear+multiprotein+complexes+and+regulates+the+transcription+of+its+own+precursor.">The APP intracellular domain forms nuclear multiprotein complexes and regulates the transcription of its own precursor.</a> J. Cell Sci. 117, 4435-4448 (2004).</li><li>Hamid, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Amyloid+precursor+protein+intracellular+domain+modulates+cellular+calcium+homeostasis+and+ATP+content.">Amyloid precursor protein intracellular domain modulates cellular calcium homeostasis and ATP content.</a> J. Neurochem. 102, 1264-1275 (2007).</li><li>Ghosal, K., Stathopoulos, A., Pimplikar, S. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=APP+intracellular+domain+impairs+adult+neurogenesis+in+transgenic+mice+by+inducing+neuroinflammation.">APP intracellular domain impairs adult neurogenesis in transgenic mice by inducing neuroinflammation.</a> PLoS ONE. 5, e11866 (2010).</li><li>Pimplikar, S. W., Suryanarayana, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Detection+of+APP+intracellular+domain+in+brain+tissue.">Detection of APP intracellular domain in brain tissue.</a> Met. Molecul. Biol. 670, 85-91 (2011).</li><li>Buchner, J., Grallert, H., Jakob, U. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Analysis+of+chaperone+function+using+citrate+synthase+as+nonnative+substrate+protein.">Analysis of chaperone function using citrate synthase as nonnative substrate protein.</a> Met. Enzymol. 290, 323-338 (1998).</li><li>Hansma, H. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Recent+advances+in+atomic+force+microscopy+of+DNA.">Recent advances in atomic force microscopy of DNA.</a> Scanning. 15, 296-299 (1993).</li><li>Valbuena, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Quasi-simultaneous+imaging/pulling+analysis+of+single+polyprotein+molecules+by+atomic+force+microscopy.">Quasi-simultaneous imaging/pulling analysis of single polyprotein molecules by atomic force microscopy.</a> Rev. Sci. Instrum. 78, 113707 (2007).</li><li>Radzimanowski, J., Beyreuther, K., Sinning, I., Wild, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Overproduction,+purification,+crystallization+and+preliminary+X-ray+analysis+of+human+Fe65-PTB2+in+complex+with+the+amyloid+precursor+protein+intracellular+domain.">Overproduction, purification, crystallization and preliminary X-ray analysis of human Fe65-PTB2 in complex with the amyloid precursor protein intracellular domain.</a> Acta Crystallogr. Sect. F Struct. Biol. Cryst. Commun. 64, 409-412 (2008).</li><li>Chen, T. Y., Liu, P. H., Ruan, C. T., Chiu, L., Kung, F. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+intracellular+domain+of+amyloid+precursor+protein+interacts+with+flotillin-1,+a+lipid+raft+protein.">The intracellular domain of amyloid precursor protein interacts with flotillin-1, a lipid raft protein.</a> Biochem. Biophys. Res. Commun. 342, 266-272 (2006).</li><li>Kim, M. Y. <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+Notch1+signaling+by+the+APP+intracellular+domain+facilitates+degradation+of+the+Notch1+intracellular+domain+and+RBP-Jk.">Regulation of Notch1 signaling by the APP intracellular domain facilitates degradation of the Notch1 intracellular domain and RBP-Jk.</a> J. Cell Sci. 124, 1831-1843 (2011).</li><li>Lazarov, O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Axonal+transport,+amyloid+precursor+protein,+kinesin-1,+and+the+processing+apparatus:+revisited.">Axonal transport, amyloid precursor protein, kinesin-1, and the processing apparatus: revisited.</a> J. Neurosci. 25, 2386-2395 (2005).</li><li>Kakuda, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Equimolar+production+of+amyloid+beta-protein+and+amyloid+precursor+protein+intracellular+domain+from+beta-carboxyl-terminal+fragment+by+gamma-secretase.">Equimolar production of amyloid beta-protein and amyloid precursor protein intracellular domain from beta-carboxyl-terminal fragment by gamma-secretase.</a> J Biol. Chem. 281, 14776-14786 (2006).</li><li>Gosal, W. S., Myers, S. L., Radford, S. E., Thomson, N. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Amyloid+under+the+atomic+force+microscope.">Amyloid under the atomic force microscope.</a> Protein Pept. Lett. 13, 261-270 (2006).</li></ol>

In this protocol we have outlined a procedure for obtaining highly pure AICD for structural, biophysical, and biochemical analyses. This procedure does not require sophisticated chromatography equipment and is therefore accessible to most laboratories. Other groups have purified AICD5-7,16, including GST-AICD17-19, for biochemical/structural analyses. Disadvantages to previous protocols include poor solubility of AICD16, less than ideal purity17, and the requirement for size ex...

<table border="1">
	<tbody>
		<tr>
			<td>Name of the reagent</td>
			<td>Company</td>
			<td>Catalogue number</td>
			<td>Comments </td>
		</tr>
		<tr>
			<td>pGEX-4T-1</td>
			<td>GE Healthcare</td>
			<td>28-9545-49</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Thrombin</td>
			<td>GE Healthcare</td>
			<td>27-0846-01</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Ampicillin</td>
			<td>Fisher Scientific</td>
			<td>BP1760</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Bradford protein assay reagent</td>
			<td>Bio-Rad</td>
			<td>500-0002</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Coomassie blue</td>
			<td>Bio-Rad</td>
			<td>161-0786</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>IPTG ( isopropyl-beta-D thiogalactopyranoside)</td>
			<td>Sigma-Aldrich</td>
			<td>I6758</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Glutathione-agarose</td>
			<td>Sigma-Aldrich</td>
			<td>G4510</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>p-aminobenzamidine-agarose</td>
			<td>Sigma-Aldrich</td>
			<td>A7155</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Complete protease inhibitor cocktail</td>
			<td>Roche</td>
			<td>11836170001</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Slide-A-Lyzer dialysis cassettes</td>
			<td>Thermo Scientific</td>
			<td>66380</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Chromatography columns</td>
			<td>Evergreen Scientific</td>
			<td>208-3367-050</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Emulsifier</td>
			<td>Avestin, Inc</td>
			<td>EmulsiFlex-C3</td>
			<td>Highly recommended</td>
		</tr>
		<tr>
			<td>Eppendorf Thermomixer</td>
			<td>Eppendorf</td>
			<td>022670107</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Mica Disks</td>
			<td>Ted Pella</td>
			<td>50-12</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>AFM cantilevers</td>
			<td>Bruker</td>
			<td>MSNL-10</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>WSxM software</td>
			<td>Nanotec</td>
			<td>N/A</td>
			<td>Free download</td>
		</tr>
	</tbody>
</table>

purification and aggregation of the amyloid precursor protein intracellular domain

Amyloid precursor protein (APP) is a type I transmembrane protein associated with the pathogenesis of Alzheimer's disease (AD). APP is characterized by a large extracellular domain and a short cytosolic domain termed the APP intracellular domain (AICD). During maturation through the secretory pathway, APP can be cleaved by proteases termed &alpha;, &beta;, and &gamma;-secretases1. Sequential proteolytic cleavage of APP with &beta; and &gamma;-secretases leads to the production of a small proteolytic peptide, termed A&beta;, which is amyloidogenic and the core constituent of senile plaques. The AICD is also liberated from the membrane after secretase processing, and through interactions with Fe65 and Tip60, can translocate to the nucleus to participate in transcription regulation of multiple target genes2,3. Protein-protein interactions involving the AICD may affect trafficking, processing, and cellular functions of holo-APP and its C-terminal fragments. We have recently shown that AICD can aggregate in vitro, and this process is inhibited by the AD-implicated molecular chaperone ubiquilin-14. Consistent with these findings, the AICD has exposed hydrophobic domains and is intrinsically disordered in vitro5,6, however it obtains stable secondary structure when bound to Fe657. We have proposed that ubiquilin-1 prevents inappropriate inter- and intramolecular interactions of AICD, preventing aggregation in vitro and in intact cells4. While most studies focus on the role of APP in the pathogenesis of AD, the role of AICD in this process is not clear. Expression of AICD has been shown to induce apoptosis8, to modulate signaling pathways9, and to regulate calcium signaling10. Over-expression of AICD and Fe65 in a transgenic mouse model induces Alzheimer's like pathology11, and recently AICD has been detected in brain lysates by western blotting when using appropriate antigen retrieval techniques12. To facilitate structural, biochemical, and biophysical studies of the AICD, we have developed a procedure to produce recombinantly large amounts of highly pure AICD protein. We further describe a method for inducing the in vitro thermal aggregation of AICD and analysis by atomic force microscopy. The methods described are useful for biochemical, biophysical, and structural characterization of the AICD and the effects of molecular chaperones on AICD aggregation.

Watch this Scientific Journal Video about Purification and Aggregation of the Amyloid Precursor Protein Intracellular Domain at JoVE.com

Purification and Aggregation of the Amyloid Precursor Protein Intracellular Domain

A method for large-scale purification of the APP intracellular domain (AICD) is described. We also describe methodology to induce in vitro AICD aggregation and visualization by atomic force microscopy. The methods described are useful for biochemical/structural characterization of the AICD and the effects of molecular chaperones on its aggregation.

Amyloid precursor protein (APP) is a type I transmembrane protein associated with the pathogenesis of Alzheimer's disease (AD). APP is characterized by a ...

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11.7K Views.  University of Texas Medical Branch. Un metodo per la grande purificazione del dominio intracellulare APP (AICD) è descritto. Abbiamo anche descrivere la metodologia di indurre In vitro AICD aggregazione e visualizzazione mediante microscopia a forza atomica. I metodi descritti sono utili per la caratterizzazione biochimica / strutturale del AICD e gli effetti di chaperone molecolare sulla sua aggregazione.