The Journal of Neuroscience, November 12, 2008, 28(46):12097-12106; doi:10.1523/JNEUROSCI.2635-08.2008
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Neurobiology of Disease
Loss of
-Secretase Function Impairs Endocytosis of Lipoprotein Particles and Membrane Cholesterol Homeostasis
Irfan Y. Tamboli,1
Kai Prager,1
Dietmar R. Thal,3
Karin M. Thelen,2
Ilse Dewachter,4
Claus U. Pietrzik,5
Peter St. George-Hyslop,6
Sangram S. Sisodia,7
Bart De Strooper,8
Michael T. Heneka,1
Mikhail A. Filippov,9
Ulrike Müller,9
Fred van Leuven,4
Dieter Lütjohann,2 and
Jochen Walter1
Departments of 1Neurology and 2Clinical Pharmacology, University of Bonn, 53127 Bonn, Germany, 3Institute of Pathology, University of Ulm, 89081 Ulm, Germany, 4Department of Human Genetics, Experimental Genetics Group, Katholieke Universiteit (K.U.) Leuven, 3000 Leuven, Belgium, 5Department of Physiological Chemistry and Pathobiochemistry, University of Mainz, 55099 Mainz, Germany, 6Center of Research in Neurodegenerative Diseases, University of Toronto, Toronto, Ontario, Canada M5S 3H2, 7Department of Neurobiology, Pharmacology, and Physiology, University of Chicago, Chicago, Illinois 60637, 8Center for Human Genetics, Flanders Interuniversity Institute for Biotechnology (VIB4) and K.U. Leuven, 3000 Leuven, Belgium, and 9Institute for Pharmacy and Molecular Biotechnology, University of Heidelberg, 69120 Heidelberg, Germany
Correspondence should be addressed to Dr. Jochen Walter, Molecular Cell Biology, University of Bonn, Sigmund-Freud-Str. 25, 53127 Bonn, Germany. Email: jochen.walter{at}ukb.uni-bonn.de
Presenilins (PSs) are components of the
-secretase complex that mediates intramembranous cleavage of type I membrane proteins. We show that
-secretase is involved in the regulation of cellular lipoprotein uptake. Loss of
-secretase function decreased endocytosis of low-density lipoprotein (LDL) receptor. The decreased uptake of lipoproteins led to upregulation of cellular cholesterol biosynthesis by increased expression of CYP51 and enhanced metabolism of lanosterol. Genetic deletion of PS1 or transgenic expression of PS1 mutants that cause early-onset Alzheimer's disease led to accumulation of
-secretase substrates and mistargeting of adaptor proteins that regulate endocytosis of the LDL receptor. Consistent with decreased endocytosis of these receptors, PS1 mutant mice have elevated levels of apolipoprotein E in the brain. Thus, these data demonstrate a functional link between two major genetic factors that cause early-onset and late-onset Alzheimer's disease.
Key words: presenilin; lipoprotein uptake; apo E; SREBP2; cholesterol; APP
Received June 10, 2008;
revised Sept. 1, 2008;
accepted Sept. 23, 2008.
Correspondence should be addressed to Dr. Jochen Walter, Molecular Cell Biology, University of Bonn, Sigmund-Freud-Str. 25, 53127 Bonn, Germany. Email: jochen.walter{at}ukb.uni-bonn.de
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D. Waschbusch, S. Born, V. Niediek, N. Kirchgessner, I. Y. Tamboli, J. Walter, R. Merkel, and B. Hoffmann
Presenilin 1 Affects Focal Adhesion Site Formation and Cell Force Generation via c-Src Transcriptional and Posttranslational Regulation
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