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Familial Alzheimer's disease mutations in amyloid protein precursor alter proteolysis by γ-secretase to increase amyloid β-peptides of ≥45 residues
Devkota S, Williams TD, Wolfe MS.. The Journal of biological chemistry, 2021-01-12
Topic: Disease mechanisms in lab and animal studies
Production of amyloid β-protein (Aβ) is carried out by the membrane-embedded γ-secretase complex. Mutations in the transmembrane domain of amyloid β-protein precursor (APP) associated with early-onset familial Alzheimer's disease (FAD) can alter the ratio of aggregation-prone 42-residue Aβ (Aβ42) to 40-residue Aβ (Aβ40). However, APP substrate is proteolyzed processively by γ-secretase along two pathways: Aβ49→Aβ46→Aβ43→Aβ40 and Aβ48→Aβ45→Aβ42→Aβ38. Effects of FAD mutations on each proteolytic step are unknown, largely due to difficulties in detecting and quantifying longer Aβ peptides. To address this, we carried out systematic and quantitative analyses of all tri- and tetrapeptide coproducts from proteolysis of wild-type and 14 FAD-mutant APP substrates by purified γ-secretase. These small peptides, including FAD-mutant forms, were detected by tandem mass spectrometry and quantified by establishing concentration curves for each of 32 standards. APP intracellular domain (AICD) coproducts were quantified by immunoblot, and the ratio of AICD products corresponding to Aβ48 and Aβ49 was determined by mass spectrometry. Levels of individual Aβ peptides were determined by subtracting levels of peptide coproducts associated with degradation from those associated with production. This method was validated for Aβ40 and Aβ42 by specific ELISAs and production of equimolar levels of Aβ and AICD. Not all mutant substrates led to increased Aβ42/40. However, all 14 disease-causing mutations led to inefficient processing of longer forms of Aβ ≥ 45 residues. In addition, the effects of certain mutations provided insight into the mechanism of processive proteolysis: intermediate Aβ peptides apparently remain bound for subsequent trimming and are not released and reassociated.
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APA 7th
Devkota, S., Williams, T. D., & Wolfe, M. S. (2021). Familial Alzheimer's disease mutations in amyloid protein precursor alter proteolysis by γ-secretase to increase amyloid β-peptides of ≥45 residues. The Journal of biological chemistry. https://doi.org/10.1016/j.jbc.2021.100281
Vancouver
Devkota S, Williams TD, Wolfe MS. Familial Alzheimer's disease mutations in amyloid protein precursor alter proteolysis by γ-secretase to increase amyloid β-peptides of ≥45 residues. The Journal of biological chemistry. 2021. doi:10.1016/j.jbc.2021.100281. PMID: 33450230.
BibTeX
@article{devkota2021-33450230,
author = {Devkota, S. and Williams, T. D. and Wolfe, M. S.},
title = {{Familial Alzheimer's disease mutations in amyloid protein precursor alter proteolysis by γ-secretase to increase amyloid β-peptides of ≥45 residues}},
journal = {The Journal of biological chemistry},
year = {2021},
doi = {10.1016/j.jbc.2021.100281},
pmid = {33450230},
url = {https://doi.org/10.1016/j.jbc.2021.100281}
}
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Key findings
- Mutations in the transmembrane domain of amyloid β-protein precursor (APP) associated with early-onset familial Alzheimer's disease (FAD) can alter the ratio of aggregation-prone 42-residue Aβ (Aβ42) to 40-residue Aβ (Aβ40).
- Levels of individual Aβ peptides were determined by subtracting levels of peptide coproducts associated with degradation from those associated with production.
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Study details
- Evidence strengthLow
How this study scored 43/100
Published in a peer-reviewed journal. Scored zero for study design, sample size, effect reported, studied in people and randomized / blinded because the record does not state it. We have no data on journal's citation record, times cited, citations per year, impact for its field and year, cited by studies here, still being cited, senior author's track record, institution's track record and multicenter collaboration, so those were left out: it earned 25 of the 58 points we could judge it on, which is 43 out of 100.
| Component | Points | Why |
|---|---|---|
| Journal tier | 7 / 10 | Tier 3 — peer-reviewed journal (The Journal of biological chemistry) |
| Journal's citation record | — / 4 | No journal record from OpenAlex — left out of this score |
| Study design | 0 / 12 | No study design recorded — scores zero, not guessed (not stated in the record — scored 0) |
| Strength of evidence | 1 / 5 | Rated “low” in our summary |
| Peer-review validation | 10 / 10 | Peer-reviewed. Published as an article in a named peer-reviewed journal. |
| How recent | 3 / 5 | 2021 — within 6 year(s) of the newest study here |
| Sample size | 0 / 4 | Participant count not stated — scores zero (not stated in the record — scored 0) |
| Effect reported | 0 / 3 | No effect size reported — scores zero (not stated in the record — scored 0) |
| Studied in people | 0 / 3 | Not stated whether this was studied in people — scores zero (not stated in the record — scored 0) |
| Randomized / blinded | 0 / 2 | No randomization or blinding stated — scores zero (not stated in the record — scored 0) |
| Times cited | — / 7 | No citation count (not found in OpenAlex) — left out of this score |
| Citations per year | — / 5 | No citation count or no year — left out of this score |
| Impact for its field and year | — / 6 | No field-weighted citation impact (OpenAlex has none yet) — left out of this score |
| Cited by studies here | — / 6 | Not yet checked against this library's citation graph — left out of this score |
| Still being cited | — / 4 | No yearly citation counts — left out of this score |
| Senior author's track record | — / 4 | Senior author's record not available — left out of this score |
| Institution's track record | — / 3 | No institution listed in OpenAlex — left out of this score |
| Multicenter collaboration | — / 3 | Institutions not listed — left out of this score |
| Indexed in PubMed | 2 / 2 | Indexed in PubMed (PMID 33450230) |
| Free to read | 2 / 2 | Free to read |
| Points | 25 / 58 | Scored on 11 of 20 parts. We have no data for the rest, so they are left out: 25 of the 58 points we could judge it on is 43 out of 100. |
| Total | 43 / 100 | — |
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