FAD mutations in presenilin-1 or amyloid precursor protein decrease the efficacy of a gamma-secretase inhibitor: evidence for direct involvement of PS1 in the gamma-secretase cleavage complex.
To investigate the mechanism of regulation of Ass production by familial Alzheimer's disease (FAD)-linked presenilin 1 (PS1), we used a cell-free system that allows de novo Ass generation to examine whether PS1 participates directly in the gamma-secretase reaction. Optimal Ass generation in vitro was achieved at mildly acidic pH and could be inhibited by the aspartyl protease inhibitor pepstatin A, consistent with the suggestion that gamma-secretase is an aspartyl protease. Dominant negative mutations of the critical transmembrane aspartates in PS1 or full deletion of PS1 did not alter the maturation of APP in the secretory pathway. Instead, PS1 had a direct effect on the inhibition of Ass production by a designed peptidomimetic inhibitor: the inhibition was significantly less effective in cells expressing FAD-causing mutations in either APP or PS1 than in cells expressing the wild-type proteins. Taken together, these findings suggest that PS1 participates physically in a complex with APP during the gamma-secretase cleavage event.
Xia
W
W
Department of Neurology, Brigham and Women's Hospital, Boston, Massachusetts 02115, USA. wxia@rics.bwh.harvard.edu
Ostaszewski
B L
BL
Kimberly
W T
WT
Rahmati
T
T
Moore
C L
CL
Wolfe
M S
MS
Selkoe
D J
DJ
D000544:Alzheimer Disease / Q000235:genetics / Q000378:metabolism*; D053829:Amyloid Precursor Protein Secretases; D016229:Amyloid beta-Peptides / Q000096:biosynthesis; D016564:Amyloid beta-Protein Precursor / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D016282:Aspartic Acid Endopeptidases / Q000037:antagonists & inhibitors / Q000378:metabolism; D001665:Binding Sites / Q000187:drug effects / Q000235:genetics; D016466:CHO Cells; D002458:Cell Fractionation; D002474:Cell-Free System / Q000378:metabolism; D006224:Cricetinae; D010450:Endopeptidases / Q000187:drug effects / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D005799:Genes, Dominant; D006056:Golgi Apparatus / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D046911:Macromolecular Substances; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D008861:Microsomes / Q000378:metabolism; D020125:Mutation, Missense; D010436:Pepstatins / Q000494:pharmacology; D053764:Presenilin-1; D011485:Protein Binding / Q000187:drug effects; D011499:Protein Processing, Post-Translational
D016229:Amyloid beta-Peptides; D016564:Amyloid beta-Protein Precursor; D004791:Enzyme Inhibitors; D046911:Macromolecular Substances; D008565:Membrane Proteins; D010436:Pepstatins; D053764:Presenilin-1; C014195:Streptomyces pepsin inhibitor; D053829:Amyloid Precursor Protein Secretases; D010450:Endopeptidases; D016282:Aspartic Acid Endopeptidases; C031375:pepstatin