Requirement for small side chain residues within the GxGD‐motif of presenilin for γ‐secretase substrate cleavage

Pérez‐Revuelta, Blanca I.; Fukumori, Akio; Lammich, Sven; Yamasaki, Aya; Haass, Christian; Steiner, Harald

doi:10.1111/j.1471-4159.2009.06510.x

Cited by 21 publications

(32 citation statements)

References 44 publications

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“…G384A and ΔE9 FAD mutations were chosen as two mutations that could have very different effect on the enzyme structure around the two active site aspartates [13]. G384A is a mutation in a highly conserved active site loop GXGD next to the active site aspartate D385 [11], [13], [16]. This apparently subtle change is the only mutation at that position that can give an active enzyme [11], [13], [16].…”

Section: Discussionmentioning

confidence: 99%

“…G384A is a mutation in a highly conserved active site loop GXGD next to the active site aspartate D385 [11], [13], [16]. This apparently subtle change is the only mutation at that position that can give an active enzyme [11], [13], [16]. ΔE9 is a mutation at a splice acceptor site that results in a deletion of a link between the two transmembrane helixes that carry the active site aspartates (amino acids 290–319 [13], [84]).…”

Section: Discussionmentioning

confidence: 99%

“…After complex posttranslational processing, the active enzyme is imbedded in cell membranes and composed of four loosely connected proteins: Aph1, Pen2, glycosylated nicastrin, and endo-proteolyzed presenilin as the catalytic core [13]. γ-Secretase is an aspartic protease [3], [14], with unique preference for some mechanism-based inhibitors [15], unique sequence motifs in the active site [11], [16], and the optimal pH close to the physiological pH [17]. The active site aspartates are located in the central aqueous cavity [18], that can be observed using electron microscopy [19].…”

Section: Introductionmentioning

confidence: 99%

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Modulation of γ-Secretase Activity by Multiple Enzyme-Substrate Interactions: Implications in Pathogenesis of Alzheimer's Disease

Svedružić¹,

Popović²,

Smoljan³

et al. 2012

PLoS ONE

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BackgroundWe describe molecular processes that can facilitate pathogenesis of Alzheimer's disease (AD) by analyzing the catalytic cycle of a membrane-imbedded protease γ-secretase, from the initial interaction with its C99 substrate to the final release of toxic Aβ peptides.ResultsThe C-terminal AICD fragment is cleaved first in a pre-steady-state burst. The lowest Aβ42/Aβ40 ratio is observed in pre-steady-state when Aβ40 is the dominant product. Aβ42 is produced after Aβ40, and therefore Aβ42 is not a precursor for Aβ40. The longer more hydrophobic Aβ products gradually accumulate with multiple catalytic turnovers as a result of interrupted catalytic cycles. Saturation of γ-secretase with its C99 substrate leads to 30% decrease in Aβ40 with concomitant increase in the longer Aβ products and Aβ42/Aβ40 ratio. To different degree the same changes in Aβ products can be observed with two mutations that lead to an early onset of AD, ΔE9 and G384A. Four different lines of evidence show that γ-secretase can bind and cleave multiple substrate molecules in one catalytic turnover. Consequently depending on its concentration, NotchΔE substrate can activate or inhibit γ-secretase activity on C99 substrate. Multiple C99 molecules bound to γ-secretase can affect processive cleavages of the nascent Aβ catalytic intermediates and facilitate their premature release as the toxic membrane-imbedded Aβ-bundles.ConclusionsGradual saturation of γ-secretase with its substrate can be the pathogenic process in different alleged causes of AD. Thus, competitive inhibitors of γ-secretase offer the best chance for a successful therapy, while the noncompetitive inhibitors could even facilitate development of the disease by inducing enzyme saturation at otherwise sub-saturating substrate. Membrane-imbedded Aβ-bundles generated by γ-secretase could be neurotoxic and thus crucial for our understanding of the amyloid hypothesis and AD pathogenesis.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Modulation of γ-Secretase Activity by Multiple Enzyme-Substrate Interactions: Implications in Pathogenesis of Alzheimer's Disease

Svedružić¹,

Popović²,

Smoljan³

et al. 2012

PLoS ONE

View full text Add to dashboard Cite

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“…(4) Some PS mutations, such as the mutations of the two catalytically required aspartate residues as well as, e.g., mutants of the GxGD (Steiner et al, 2000;Pérez-Revuelta et al, 2010) and PAL motifs (Wang et al, 2004(Wang et al, , 2006Nakaya et al, 2005) of the active site and certain mutations within the exon 8-encoded domain, are complete or severe loss-of-function mutations, strongly reducing or even totally preventing endoproteolysis and substrate cleavage (Laudon et al, 2004;Nakaya et al, 2005). Lack of the catalytically required aspartate residues is an obvious cause for such a failure.…”

Section: Discussionmentioning

confidence: 99%

Three-Amino Acid Spacing of Presenilin Endoproteolysis Suggests a General Stepwise Cleavage of -Secretase-Mediated Intramembrane Proteolysis

Fukumori¹,

Fluhrer²,

Steiner³

et al. 2010

Journal of Neuroscience

100

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Presenilin (PS1 or PS2) is the catalytic component of the ␥-secretase complex, which mediates the final proteolytic processing step leading to the Alzheimer's disease (AD)-characterizing amyloid ␤-peptide. PS is cleaved during complex assembly into its characteristic N-and C-terminal fragments. Both fragments are integral components of physiologically active ␥-secretase and harbor the two critical aspartyl residues of the active site domain. While the minimal subunit composition of ␥-secretase has been defined and numerous substrates were identified, the cellular mechanism of the endoproteolytic cleavage of PS is still unclear. We addressed this pivotal question by investigating whether familial AD (FAD)-associated PS1 mutations affect the precision of PS endoproteolysis in a manner similar to the way that such mutations shift the intramembrane cleavage of ␥-secretase substrates. We demonstrate that all FAD mutations investigated still allow endoproteolysis to occur. However, the precision of PS1 endoproteolysis is affected by PS1 mutations. Comparing the cleavage products generated by a variety of PS1 mutants revealed that specifically cleavages at positions 293 and 296 of PS1 are selectively affected. Systematic mutagenesis around the cleavage sites revealed a stepwise three amino acid spaced cleavage mechanism of PS endoproteolysis reminiscent to the -, -, and ␥-cleavages described for typical ␥-secretase substrates, such as the ␤-amyloid precursor protein. Our findings therefore suggest that intramembranous cleavage by ␥-secretase and related intramembrane-cleaving proteases may generally occur via stepwise endoproteolysis.

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“…For the GLGD motif, besides the G384A mutant described above, the G382A mutant was chosen. Both mutants are the only known substitutions of the glycine residue, which are functionally tolerated for APP processing (29,30). Considerably more amino acid substitutions are tolerated for APP processing for the more flexible X position of the motif (Leu-383), but only a few mutants at this position cause an increased production of A␤ 42 .…”

Section: Effective Lowering Of A␤mentioning

confidence: 99%

Attenuated Aβ42 Responses to Low Potency γ-Secretase Modulators Can Be Overcome for Many Pathogenic Presenilin Mutants by Second-generation Compounds

Kretner

Fukumori

Gutsmiedl

et al. 2011

Journal of Biological Chemistry

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Sequential processing of the ␤-amyloid precursor protein by ␤-and ␥-secretase generates the amyloid ␤-peptide (A␤), which is widely believed to play a causative role in Alzheimer disease. Selective lowering of the pathogenic 42-amino acid variant of A␤ by ␥-secretase modulators (GSMs) is a promising therapeutic strategy. Here we report that mutations in presenilin (PS), the catalytic subunit of ␥-secretase, display differential responses to non-steroidal anti-inflammatory drug (NSAID)-type GSMs and more potent second-generation compounds. Although many pathogenic PS mutations resisted lowering of A␤ 42 generation by the NSAID sulindac sulfide, the potent NSAID-like second-generation compound GSM-1 was capable of lowering A␤ 42 for many but not all mutants. We further found that mutations at homologous positions in PS1 and PS2 can elicit differential A␤ 42 responses to GSM-1, suggesting that a positive GSM-1 response depends on the spatial environment in ␥-secretase. The aggressive pathogenic PS1 L166P mutation was one of the few pathogenic mutations that resisted GSM-1, and Leu-166 was identified as a critical residue with respect to the A␤ 42 -lowering response of GSM-1. Finally, we found that GSM-1-responsive and -resistant PS mutants behave very similarly toward other potent second-generation compounds of different structural classes than GSM-1. Taken together, our data show that a positive A␤ 42 response for PS mutants depends both on the particular mutation and the GSM used and that attenuated A␤ 42 responses to low potency GSMs can be overcome for many PS mutants by second generation GSMs. The amyloid ␤-peptide (A␤)4 is a 37-43-amino acid secreted peptide and an invariant pathological hallmark of Alzheimer disease (AD). The 42-amino acid variant A␤ 42 has been suggested to be causative for the disease by triggering the amyloid cascade, a sequence of pathogenic events that ultimately leads to neurodegeneration and dementia in affected patients (1). The pathogenic peptide is generated by a sequential cleavage of the ␤-amyloid precursor protein (APP) by ␤-and ␥-secretase (2). After ␤-secretase cleavage, ␥-secretase cleaves the C-terminal fragment of APP that is left in the membrane by an intramembrane cleavage to release the various A␤ species (3-5). Although A␤ 42 is normally a minor species produced by this cleavage besides the major A␤ 40 species, its production is enhanced by familial AD (FAD) mutations in presenilin (PS) 1 and PS2, the catalytic component of ␥-secretase (6), as well as by a subset of FAD mutations in APP. Targeting ␤-and ␥-secretase by specific inhibitors is one of the current approaches toward an effective AD treatment (7). With respect to ␥-secretase, however, ␥-secretase inhibitors also block the cleavage of Notch1, a major physiological ␥-secretase substrate and, thus, the generation of the Notch1 intracellular domain (NICD), which is a crucial signaling molecule controlling cell differentiation (7). Interfering with the cleavage of this substrate accounts for adverse side effects in...

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Requirement for small side chain residues within the GxGD‐motif of presenilin for γ‐secretase substrate cleavage

Cited by 21 publications

References 44 publications

Modulation of γ-Secretase Activity by Multiple Enzyme-Substrate Interactions: Implications in Pathogenesis of Alzheimer's Disease

Modulation of γ-Secretase Activity by Multiple Enzyme-Substrate Interactions: Implications in Pathogenesis of Alzheimer's Disease

Three-Amino Acid Spacing of Presenilin Endoproteolysis Suggests a General Stepwise Cleavage of -Secretase-Mediated Intramembrane Proteolysis

Attenuated Aβ42 Responses to Low Potency γ-Secretase Modulators Can Be Overcome for Many Pathogenic Presenilin Mutants by Second-generation Compounds

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