Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2010 Nov 12;402(2):291-6.
doi: 10.1016/j.bbrc.2010.10.017. Epub 2010 Oct 16.

Dependency of γ-secretase complex activity on the structural integrity of the bilayer

Hua Zhou  1 , Shuxia Zhou, Peter J Walian, Bing K Jap
Affiliations

Dependency of γ-secretase complex activity on the structural integrity of the bilayer

Hua Zhou et al. Biochem Biophys Res Commun. .

Abstract

γ-secretase is a membrane protein complex associated with the production of Aβ peptides that are pathogenic in Alzheimer's disease. We have characterized the activity of γ-secretase complexes under a variety of detergent solubilization and reconstitution conditions, and the structural state of proteoliposomes by electron microscopy. We found that γ-secretase activity is highly dependent on the physical state or integrity of the membrane bilayer--partial solubilization may increase activity while complete solubilization will abolish it. The activity of well-solubilized γ-secretase can be restored to near native levels when properly reconstituted into a lipid bilayer environment.

PubMed Disclaimer

Figures

Figure 1
Figure 1. Detergent titration of HeLa cell membranes containing γ-secretase complexes
Treatment with low levels of CHAPSO (up to 0.5 CMC) can yield γ-secretase activity greater than that obtained with native membrane preparations. Use of FOS-CHOLINE-12 and DDM yield the anticipated drop in activity beginning with the smallest amounts added.
Figure 2
Figure 2. Treatment of γ-secretase containing cell membranes with low levels (0.5 CMC) of CHAPSO
Such treatment converts a) starting HeLa cell membranes into b) smaller bilayer fragments without significant solubilization of protein complexes. Size bars indicate 1 µm.
Figure 3
Figure 3. Restoration of γ-secretase activity by reconstitution of detergent-solubilized complexes into lipid bilayers (vesicles)
HeLa cell membranes were solubilized in one of four different detergents, FOS-CHOLINE-12 and -14, DDM and CHAPSO. The charts of the left-hand panel show the relative activity levels of γ-secretase complexes in their detergent-solubilized and reconstituted forms with and without the presence of γ-secretase inhibitor L-685,458. The middle panel micrographs show aggregates of inactive detergent-solubilized membranes. Activity was restored upon reconstitution of γ-secretase complexes into lipid vesicles (right panel). Size bars indicate 1µm.
Figure 4
Figure 4. Purified γ-secretase complexes regain activity upon reconstitution into lipid bilayers
γ-Secretase complexes were solubilized in FOS-CHOLINE-12, chromatographically purified and reconstituted using brain total lipid extract. Total γ-secretase complex levels in each sample were adjusted to be equal and confirmed by quantitative western blot. Reconstituted and native samples show high activity and give similar reductions in activity when treated with inhibitor L-685,458.
See this image and copyright information in PMC

Similar articles

See all similar articles

Cited by

References

    1. Li YM, Xu M, Lai MT, Huang Q, Castro JL, DiMuzio-Mower J, Harrison T, Lellis C, Nadin A, Neduvelil JG, Register RB, Sardana MK, Shearman MS, Smith AL, Shi XP, Yin KC, Shafer JA, Gardell SJ. Photoactivated γ-secretase inhibitors directed to the active site covalently label presenilin 1. Nature. 2000;405:689–694. - PubMed
    1. Esler WP, Wolfe MS. A portrait of Alzheimer secretases-new features and familiar faces. Science. 2001;293:1449–1454. - PubMed
    1. Periz G, Fortini ME. Functional reconstitution of gamma-secretase through coordinated expression of presenilin, nicastrin, Aph-1, and Pen-2. J. Neurosci. Res. 2004;77:309–322. - PubMed
    1. Wolfe MS. The gamma-secretase complex: membrane-embedded proteolytic ensemble. Biochemistry. 2006;45:7931–7939. - PubMed
    1. Thinakaran G, Borchelt DR, Lee MK, Slunt HH, Spitzer L, Kim G, Ratovitsky T, Davenport F, Nordstedt C, Seeger M, Hardy J, Levey AI, Gandy SE, Jenkins NA, Copeland NG, Price DL, Sisodia SS. Endoproteolysis of presenilin 1 and accumulation of processed derivatives in vivo. Neuron. 1996;17:181–190. - PubMed

Publication types

MeSH terms

LinkOut - more resources