Assembly of γ-secretase occurs through stable dimers after exit from the endoplasmic reticulum
Wouters, Rosanne; Michiels, Christine; Sannerud, Ragna; Kleizen, Bertrand; Dillen, Katleen; Vermeire, Wendy; Ayala, Abril Escamilla; Demedts, David; Schekman, Randy; Annaert, Wim
(2021) Journal of Cell Biology, volume 220, issue 9, pp. 1 - 26
(Article)
Abstract
γ-Secretase affects many physiological processes through targeting >100 substrates; malfunctioning links γ-secretase to cancer and Alzheimer’s disease. The spatiotemporal regulation of its stoichiometric assembly remains unresolved. Fractionation, biochemical assays, and imaging support prior formation of stable dimers in the ER, which, after ER exit, assemble into full complexes. In vitro
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ER budding shows that none of the subunits is required for the exit of others. However, knockout of any subunit leads to the accumulation of incomplete subcomplexes in COPII vesicles. Mutating a DPE motif in presenilin 1 (PSEN1) abrogates ER exit of PSEN1 and PEN-2 but not nicastrin. We explain this by the preferential sorting of PSEN1 and nicastrin through Sec24A and Sec24C/D, respectively, arguing against full assembly before ER exit. Thus, dimeric subcomplexes aided by Sec24 paralog selectivity support a stepwise assembly of γ-secretase, controlling final levels in postGolgi compartments.
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Keywords: Amyloid Precursor Protein Secretases/chemistry, Animals, Biological Transport, COP-Coated Vesicles/chemistry, Cell Line, Cell Line, Tumor, Cerebral Cortex/cytology, Endopeptidases/chemistry, Endoplasmic Reticulum/metabolism, Fibroblasts/cytology, Gene Expression Regulation, Golgi Apparatus/metabolism, Humans, Membrane Proteins/chemistry, Mice, Models, Molecular, Neurons/cytology, Presenilin-1/chemistry, Primary Cell Culture, Protein Binding, Protein Conformation, Protein Isoforms/chemistry, Protein Multimerization, Rats, Rats, Wistar, Signal Transduction, Vesicular Transport Proteins/genetics
ISSN: 0021-9525
Publisher: Rockefeller University Press
Note: Funding Information: Research Foundation (S#20030). R. Wouters held a Research Foundation–Flanders aspirant fellowship, and B. Kleizen held a long-term European Molecular Biology Organization fellowship. R. Schekman is supported as an investigator of the Howard Hughes Medical Institute and the Adolph C. and Mary Sprague Miller Institute for Basic Research in Science, University of California, Berkeley. The authors declare no competing financial interests. Funding Information: We thank P. Wong (Baltimore, MD) for NCT KO MEFs and B. De Strooper (Katholieke Universiteit Leuven, Leuven, Belgium) for other subunit KO MEFs. This work was financed through Vlaams Instituut voor Biotechnologie, Katholieke Universiteit Leuven (C16/15/073, C14/21/095), Research Foundation?Flanders (S006617N, G078117N, G056017N, AKUL13/39), and Stichting AlzheimerOnderzoek?Alzheimer Research Foundation (S#20030). R. Wouters held a Research Foundation?Flanders aspirant fellowship, and B. Kleizen held a long-term European Molecular Biology Organization fellowship. R. Schekman is supported as an investigator of the Howard Hughes Medical Institute and the Adolph C. and Mary Sprague Miller Institute for Basic Research in Science, University of California, Berkeley. The authors declare no competing financial interests.. Funding Information: This work was financed through Vlaams Instituut voor Bio-technologie, Katholieke Universiteit Leuven (C16/15/073, C14/21/095), Research Foundation–Flanders (S006617N, G078117N, G056017N, AKUL13/39), and Stichting Alzheimer Onderzoek–Alzheimer Publisher Copyright: © 2021 Wouters et al.
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