Presenilin-1 and Presenilin-2 Exhibit Distinct yet Overlapping γ-Secretase Activities

Lai, Ming‐Tain; Chen, Elizabeth; Crouthamel, Ming-Chih; DiMuzio-Mower, Jillian; Xu, Min; Huang, Qian; Price, Eric A.; Register, R B; Shi, Xiao‐Ping; Donoviel, Dorit B.; Bernstein, Alan; Hazuda, Daria J.; Gardell, Stephen J.; Li, Yueming

doi:10.1074/jbc.m300974200

Cited by 155 publications

(164 citation statements)

References 33 publications

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“…Conditioned media was then harvested for Aβ ELISA at the same time that cell lysates were harvested for AICD-GVP ELISA or Luciferase assay. Consistent with previous reports [10, 11, 13], the Aβ ELISA demonstrated that PS1 generates approximately five-fold more Aβ than PS2 (Fig. 1B ), thereby validating our substrate and cell-based system.…”

Section: Resultssupporting

confidence: 92%

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Evidence that Enzyme Processivity Mediates Differential Aβ Production by PS1 and PS2

Pintchovski¹,

Basi²

2013

Current Alzheimer Research

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The γ-secretase complex cleaves the carboxy-terminal 99 residue (C99) fragment of the amyloid precursor protein (APP) to generate the amyloid-β (Aβ) peptide. The catalytic activity of this complex is mediated either by the presenilin-1 (PS1) or the presenilin-2 (PS2) subunit. In vitro and in vivo studies have demonstrated that PS1-containing complexes generate more total Aβ product than PS2-containing complexes, indicating greater cleavage activity by PS1-containing γ-secretase complexes at the APP γ-site. However, it remains untested whether γ-secretase cleavage at the APP ε-site, which precedes γ-site cleavage and produces the physiologically active APP intracellular domain (AICD), follows the same rule. Using a novel Swedish APP-GVP substrate to facilitate the parallel detection of Aβ and AICD products from PS1-/-/PS2-/- cells co-transfected with either PS1 or PS2, we observed that while PS1 generates more total Aβ product than PS2, consistent with published reports, PS1 and PS2 unexpectedly generate equal amounts of AICD product. We also observed that PS1 and PS2 produce equivalent amounts of Notch intracellular domain (NICD), indicating equal cleavage activity at the Notch S3-site (the corollary of the APP ε-site). Our findings suggest that processivity differences between PS1 and PS2 underlie the differential production of Aβ peptide. Taken together these findings offer novel insights into γ-secretase biology and have important implications for therapeutically targeting γ-secretase

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Section: Resultssupporting

confidence: 92%

“…One possible explanation is that the difference in Aβ production is due to a mechanistic difference in the way that PS1 and PS2 recognize and/or cleave APP substrate. A parsimonious explanation for the greater production of Aβ by PS1 is that PS1-containing γ-secretase is a more active enzyme than PS2-containing γ-secretase [11]. …”

Section: Introductionmentioning

confidence: 99%

Evidence that Enzyme Processivity Mediates Differential Aβ Production by PS1 and PS2

Pintchovski¹,

Basi²

2013

Current Alzheimer Research

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“…A small fraction of total PS1 has been found at the cell surface (33). It has been established that PSs are essential but not sufficient for ␥-secretase activity, and only a small portion of PS1 resides in the active ␥-secretase complex (37). Therefore, these studies only provide indirect evidence that PS1, engaged in the active ␥-secretase, may exist in the plasma membrane.…”

Section: Discussionmentioning

confidence: 57%

“…MRL631 and MRL505 were kindly provided by Merck Research Laboratories. HEK293 cells were transiently transfected with an expression vector containing the fragment of APP corresponding to the membrane-bound C-terminal stub (APP-C99) produced by ␤-secretase (37). pGreen-Lantern-1, which contains the gene for the green fluorescence protein (Life Technologies, Grand Island, NY), was also cotransfected for normalization of the transfection efficiency.…”

Section: Methodsmentioning

confidence: 99%

Processing of Notch and amyloid precursor protein by γ-secretase is spatially distinct

Tarassishin

Yin

Bassit

et al. 2004

Proc. Natl. Acad. Sci. U.S.A.

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103

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␥-Secretase activity is associated with a presenilin (PS)-containing macromolecular complex. Whether PS contains the active site of ␥-secretase has been controversial. One challenge is to find PS that is engaged in the active ␥-secretase complex at the cell surface, where some substrates appear to be processed. In this study, we developed an intact cell photolabeling technique that allows the direct visualization of active ␥-secretase at the cell surface. We demonstrated that active ␥-secretase is present in the plasma membrane. Moreover, the PS1 heterodimer is specifically photolabeled at the cell surface by a potent inhibitor that binds to only the active ␥-secretase. We also explored the cellular processing sites of ␥-secretase for amyloid precursor protein (APP) and Notch by using small molecular probes. MRL631, a ␥-secretase inhibitor that is unable to penetrate the cell membrane, significantly blocks ␥-secretase-mediated Notch cleavage but has little effect on APP processing. These results indicate that Notch is processed at the cell surface and that the majority of APP is processed by intracellular ␥-secretase. Furthermore, the fact that inhibitors first target ␥-secretase in the plasma membrane for Notch processing, and not for APP, will have important implications for drug development to treat Alzheimer's disease and cancer.intact cell photolabeling ͉ intramembrane protease ͉ presenilin

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“…Divergent effects on the production of A␤40 and A␤42 are of particular interest. Comparisons of PS1-and PS2-deficient blastocyst-derived cells suggest an important shared contribution to A␤40 production, although PS2 containing ␥-secretase complexes from blastocyst-derived cells may have lower specific activity than analogous PS1 complexes (29). Transgenic studies in a PS1-deficient background (Fig.…”

Section: Discussionmentioning

confidence: 99%

Dissociated phenotypes in presenilin transgenic mice define functionally distinct γ-secretases

Mastrangelo

Mathews²,

Chishti³

et al. 2005

Proc. Natl. Acad. Sci. U.S.A.

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␥-secretase depends on presence of presenilins (PS), Nct, Aph-1, and PEN-2 within a core complex. This endoproteolytic activity cleaves within transmembrane domains of amyloid-␤ precursor protein (APP) and Notch, and familial Alzheimer's disease (FAD) mutations in PS1 or PS2 genes shift APP cleavage from production of amyloid-␤ (A␤) 40 peptide to greater production of A␤42. Although studies in PS1͞PS2-deficient embryonic cells define overlapping activities for these proteins, in vivo complementation of PS1-deficient animals described here reveals an unexpected spectrum of activities dictated by PS1 and PS2 alleles. Unlike PS1 transgenes, wild-type PS2 transgenes expressed in the mouse CNS support little A␤40 or A␤42 production, and FAD PS2 alleles support robust production of only A␤42. Although wild-type PS2 transgenes failed to rescue Notch-associated skeletal defects in PS1 hypomorphs, a ''gained'' competence in this regard was apparent for FAD alleles of PS2. The range of discrete and divergent processing activities in mice reconstituted with different PS genes and alleles argues against ␥-secretase being a single enzyme with intrinsically relaxed substrate and cleavage site specificities. Instead, our studies define functionally distinct ␥-secretase variants. We speculate that extrinsic components, in combination with core complexes, may tailor functional variants of this enzyme to their preferred substrates.

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Presenilin-1 and Presenilin-2 Exhibit Distinct yet Overlapping γ-Secretase Activities

Cited by 155 publications

References 33 publications

Evidence that Enzyme Processivity Mediates Differential Aβ Production by PS1 and PS2

Evidence that Enzyme Processivity Mediates Differential Aβ Production by PS1 and PS2

Processing of Notch and amyloid precursor protein by γ-secretase is spatially distinct

Dissociated phenotypes in presenilin transgenic mice define functionally distinct γ-secretases

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