HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

J. Biol. Chem., Vol. 283, Issue 25, 17039-17048, June 20, 2008

This Article Full Text Full Text (PDF) Supplemental Data All Versions of this Article: 283/25/17039    most recent M706316200v1 Submit a Letter to Editor Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Llovera, R. E. Articles by Castaño, E. M. Search for Related Content PubMed PubMed Citation Articles by Llovera, R. E. Articles by Castaño, E. M. Social Bookmarking                      What's this?

The Catalytic Domain of Insulin-degrading Enzyme Forms a Denaturant-resistant Complex with Amyloid β Peptide

IMPLICATIONS FOR ALZHEIMER DISEASE PATHOGENESIS^*

Ramiro E. Llovera, Matías de Tullio, Leonardo G. Alonso, Malcolm A. Leissring, Sergio B. Kaufman^¶1, Alex E. Roher^||, Gonzalo de Prat Gay¹, Laura Morelli¹, and Eduardo M. Castaño¹²

From the Fundación Instituto Leloir-Instituto de Investigaciones Bioquímicas de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), 435 Av. Patricias Argentinas, Ciudad de Buenos Aires C1405BWE, Argentina, the Department of Biomedical Sciences, Scripps Florida, Jupiter, Florida 33458, the ^¶Instituto de Química y Fisicoquímica Biológicas-CONICET and Departamento de Química Biológica, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Buenos Aires, Argentina, and the ^||Sun Health Research Institute, Sun City, Arizona 85351

Insulin-degrading enzyme (IDE) is central to the turnover of insulin and degrades amyloid β (Aβ) in the mammalian brain. Biochemical and genetic data support the notion that IDE may play a role in late onset Alzheimer disease (AD), and recent studies suggest an association between AD and diabetes mellitus type 2. Here we show that a natively folded recombinant IDE was capable of forming a stable complex with Aβ that resisted dissociation after treatment with strong denaturants. This interaction was also observed with rat brain IDE and detected in an SDS-soluble fraction from AD cortical tissue. Aβ sequence 17–27, known to be crucial in amyloid assembly, was sufficient to form a stable complex with IDE. Monomeric as opposed to aggregated Aβ was competent to associate irreversibly with IDE following a very slow kinetics (t 45 min). Partial denaturation of IDE as well as preincubation with a 10-fold molar excess of insulin prevented complex formation, suggesting that the irreversible interaction of Aβ takes place with at least part of the substrate binding site of the protease. Limited proteolysis showed that Aβ remained bound to a 25-kDa N-terminal fragment of IDE in an SDS-resistant manner. Mass spectrometry after in gel digestion of the IDE ·Aβ complex showed that peptides derived from the region that includes the catalytic site of IDE were recovered with Aβ. Taken together, these results are suggestive of an unprecedented mechanism of conformation-dependent substrate binding that may perturb Aβ clearance, insulin turnover, and promote AD pathogenesis.

Received for publication, July 31, 2007 , and in revised form, April 11, 2008.

^* This work was supported in part by grants from the Alzheimer's Association (to E. M. C.) and the Agencia de Promoción Científica y Tecnológica (to L. M. and E. M. C.). The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

The on-line version of this article (available at http://www.jbc.org) contains supplemental Figs. S1–S5 and Table S1.

¹ Members of the Consejo Nacional de Investigaciones Científicas y Técnicas.

² To whom correspondence should be addressed: Tel.: 54-11-5238-7500; Fax: 54-11-5238-7501; E-mail: ecastano{at}leloir.org.ar.

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?

This article has been cited by other articles:

				I. Torres-Aleman Mouse Models of Alzheimer's Dementia: Current Concepts and New Trends Endocrinology, December 1, 2008; 149(12): 5952 - 5957. [Abstract] [Full Text] [PDF]