Changes in γ-secretase activity and specificity caused by the introduction of consensus aspartyl protease active motif in Presenilin 1
| Autor: | Denise D McKinley, Adele M. Pauley, Carol S Himes, Nancy C. Stratman, Alfredo G. Tomasselli, Brenda R Ellerbrook, Edwige Dunn, Donald B. Carter, Jeffrey S. Nye, Timothy J. Fleck, Riqiang Yan, Xiangdong Zhou |
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| Jazyk: | angličtina |
| Předmět: |
Mutant
Clinical Neurology lcsh:Geriatrics Cleavage (embryo) lcsh:RC346-429 Presenilin 03 medical and health sciences Cellular and Molecular Neuroscience 0302 clinical medicine mental disorders Amyloid precursor protein Molecular Biology lcsh:Neurology. Diseases of the nervous system 030304 developmental biology chemistry.chemical_classification 0303 health sciences biology Rational design Wild type Molecular medicine lcsh:RC952-954.6 Enzyme chemistry Biochemistry biology.protein Neurology (clinical) 030217 neurology & neurosurgery Research Article |
| Zdroj: | Molecular Neurodegeneration Molecular Neurodegeneration, Vol 3, Iss 1, p 6 (2008) |
| ISSN: | 1750-1326 |
| DOI: | 10.1186/1750-1326-3-6 |
| Popis: | Presenilin (PS1 or PS2) is an essential component of the active γ-secretase complex that liberates the Aβ peptides from amyloid precursor protein (APP). PS1 is regarded as an atypical aspartyl protease harboring two essential aspartic acids in the context of the sequence D257LV and D385FI, respectively, rather than the typical DTG...DTG catalytic motif of classical aspartyl proteases. In the present studies, we introduced the sequence DTG in PS1 at and around the catalytic D257 and D385 residues to generate three PS1 mutants: D257TG, D385TG, and the double-mutant D257TG/D385TG. The effects of these changes on the γ-secretase activity in the presence or absence of γ-secretase inhibitors and modulators were investigated. The results showed that PS1 mutants having D385TG robustly enhanced Aβ42 production compared to the wild type (wt), and were more sensitive than wt to inhibition by a classical aspartyl protease transition state mimic, and fenchylamine, a sulfonamide derivative. Unlike wt PS1 and some of its clinical mutants, all three PS1 artificial mutants decreased cleavage of Notch S3-site, suggesting that these artificial mutations may trigger conformational changes at the substrate docking and catalytic site that cause alteration of substrate specificity and inhibition pattern. Consistent with this notion, we have found that NSAID enzymatic inhibitors of COX, known modulators of the γ-secretase activity, cause PS1 mutants containing D385TG to produce higher levels of both Aβ38 and Aβ42, but to reduce levels of Aβ39, showing a pattern of Aβ formation different from that observed with wild type PS1 and its clinical mutants. This study provides an important structural clue for the rational design of drugs to inhibit processing of APP at the γ-site without interfering with Notch processing. |
| Databáze: | OpenAIRE |
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