Allosteric regulation of γ-secretase activity by a phenylimidazole-type γ-secretase modulator

Takeo, Koji; Tanimura, Shun; Shinoda, Takehiro; Osawa, Satoko; Zahariev, Ivan Krasmirov; Takegami, Naoki; Ishizuka-Katsura, Yoshiko; Shinya, Naoko; Takagi-Niidome, Shizuka; Tominaga, Aya; Ohsawa, Noboru; Kimura‐Someya, Tomomi; Shirouzu, Mikako; Yokoshima, Satoshi; Yokoyama, Shigeyuki; Fukuyama, Tohru; Tomita, Taisuke; Iwatsubo, Takeshi

doi:10.1073/pnas.1402171111

Cited by 70 publications

(72 citation statements)

References 46 publications

(68 reference statements)

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“…Notably, total c-secretase activity was unaffected by the GSM. Conformational changes in the presenilin active site region upon GSM binding that have been reported earlier [46] may therefore affect c-secretase at this level. However, since clear effects of allosteric modulation by RO7019009 at this major interaction site of c-secretase were observed only at very high concentrations of the GSM, it is probable that these effects are not relevant for the activity of the GSM.…”

Section: Discussionmentioning

confidence: 63%

Aβ43‐producing PS1 FAD mutants cause altered substrate interactions and respond to γ‐secretase modulation

Trambauer¹,

Sarmiento

Fukumori

et al. 2019

EMBO Reports

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Abnormal generation of neurotoxic amyloid-b peptide (Ab) 42/43 species due to mutations in the catalytic presenilin 1 (PS1) subunit of c-secretase is the major cause of familial Alzheimer's disease (FAD). Deeper mechanistic insight on the generation of Ab43 is still lacking, and it is unclear whether c-secretase modulators (GSMs) can reduce the levels of this Ab species. By comparing several types of Ab43-generating FAD mutants, we observe that very high levels of Ab43 are often produced when presenilin function is severely impaired. Altered interactions of C99, the precursor of Ab, are found for all mutants and are independent of their particular effect on Ab production. Furthermore, unlike previously described GSMs, the novel compound RO7019009 can effectively lower Ab43 production of all mutants. Finally, substrate-binding competition experiments suggest that RO7019009 acts mechanistically after initial C99 binding. We conclude that altered C99 interactions are a common feature of diverse types of PS1 FAD mutants and that also patients with Ab43-generating FAD mutations could in principle be treated by GSMs.

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Section: Discussionmentioning

confidence: 63%

Aβ43‐producing PS1 FAD mutants cause altered substrate interactions and respond to γ‐secretase modulation

Trambauer¹,

Sarmiento

Fukumori

et al. 2019

EMBO Reports

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“…Our data are consistent with other reports that IAP cleavage is sluggish, but it is challenging to further compare our study to analogous ones of γ-secretase. For example, experiments using C100FRET to study γ-secretase kinetics did not convert to an absolute scale (40,41). In other studies, where initial rates were evaluated via immunoblot quantitation after a set incubation time, our Km is either 10-fold weaker (33) or 30-fold tighter than that of γ-secretase (42).…”

Section: Resultsmentioning

confidence: 99%

Both positional and chemical variables control in vitro proteolytic cleavage of a presenilin ortholog

Naing

Kalyoncu

Smalley³

et al. 2018

Journal of Biological Chemistry

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Mechanistic details of intramembrane aspartyl protease (IAP) chemistry, which is central to many biological and pathogenic processes, remain largely obscure. Here, we investigated the in vitro kinetics of a microbial intramembrane aspartyl protease (mIAP) fortuitously acting on the renin substrate angiotensinogen and the C-terminal transmembrane segment of amyloid precursor protein (C100), which is cleaved by the presenilin subunit of γ-secretase, an Alzheimer disease (AD)-associated IAP. mIAP variants with substitutions in active-site and putative substrate gating residues generally exhibit impaired, but not abolished, activity toward angiotensinogen, and retain the predominant cleavage site (His-Thr). The aromatic ring, but not its hydroxyl substituent, in Tyr of the catalytic Tyr-Asp (YD) motif plays a catalytic role, and the hydrolysis reaction incorporates bulk water as in soluble aspartyl proteases. mIAP hydrolyzes the transmembrane region of C100 at two major presenilin cleavage sites, one corresponding to the AD-associated Aβ42 peptide (Ala-Thr) and the other the nonpathogenic Aβ48 (Thr-Leu). For the former site, we observed more favorable kinetics in lipid bilayer-mimicking bicelles than in detergent solution, indicating that substrate-lipid and substrate-enzyme interactions both contribute to catalytic rates. High-resolution MS analyses across four substrates support a preference for threonine at the scissile bond. However, results from threonine-scanning mutagenesis of angiotensinogen indicate a competing positional preference for cleavage. Our results indicate that IAP cleavage is controlled by both positional and chemical factors, opening up new avenues for selective IAP inhibition for therapeutic interventions. INTRODUCTIONIntramembrane proteases (IPs) cleave within a transmembrane (TM) helix of membranebound substrates to release cytoplasmic or extracellular proteins/peptides, which in turn translocate to different regions of the cell where they elicit their corresponding biological response related to, for example, cell differentiation, development, and metabolism (1). Despite their broad biomedical reach, basic questions surrounding the structure of the active enzyme, how substrates are presented, and how hydrolysis chemistry occurs in an active site sequestered within the hydrophobic lipid membrane, remain active areas of research.The least biochemically understood IP is the intramembrane aspartyl protease (IAP) enzyme class, one of just three bona fide IP types that hydrolyze substrates within the hydrophobic lipid environment by using different catalytic nucleophiles (2). IAPs employ membrane-

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“…Indeed, the functionally important residues of the PSEN1 endoproteolytic cleavage site lie at or around amino acid 298. By contrast, recent work on g-secretase modulators has highlighted the importance of an N-terminal, predominantly precodon 200 region of PSEN1, in the carboxypeptidase-like activity that alters Ab profiles (Ohki et al, 2011;Takeo et al, 2014). One could speculate that mutations involving this allosteric core may alter more dramatically the Ab profiles and cause a more aggressive phenotype.…”

Section: Discussionmentioning

confidence: 97%

Genetic determinants of white matter hyperintensities and amyloid angiopathy in familial Alzheimer's disease

Ryan

Biessels

Kim

et al. 2015

Neurobiology of Aging

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Familial Alzheimer's disease (FAD) treatment trials raise interest in the variable occurrence of cerebral amyloid angiopathy (CAA); an emerging important factor in amyloid-modifying therapy. Previous pathological studies reported particularly severe CAA with postcodon 200 PSEN1 mutations and amyloid beta coding domain APP mutations. As CAA may manifest as white matter hyperintensities (WMH) on magnetic resonance imaging, particularly posteriorly, we investigated WMH in 52 symptomatic FAD patients for associations with mutation position. WMH were visually rated in 39 PSEN1 (18 precodon 200); 13 APP mutation carriers and 25 healthy controls. Ten PSEN1 mutation carriers (5 precodon 200) had postmortem examination. Increased WMH were observed in the PSEN1 postcodon 200 group and in the single APP patient with an amyloid beta coding domain (p.Ala692Gly, Flemish) mutation. WMH burden on MRI correlated with severity of CAA and cotton wool plaques in several areas. The precodon 200 group had younger ages at onset, decreased axonal density and/or integrity, and a greater T-lymphocytic response in occipital deep white matter. Mutation site contributes to the phenotypic and pathological heterogeneity witnessed in FAD.

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Allosteric regulation of γ-secretase activity by a phenylimidazole-type γ-secretase modulator

Cited by 70 publications

References 46 publications

Aβ43‐producing PS1 FAD mutants cause altered substrate interactions and respond to γ‐secretase modulation

Aβ43‐producing PS1 FAD mutants cause altered substrate interactions and respond to γ‐secretase modulation

Both positional and chemical variables control in vitro proteolytic cleavage of a presenilin ortholog

Genetic determinants of white matter hyperintensities and amyloid angiopathy in familial Alzheimer's disease

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