A presenilin dimer at the core of the gamma-secretase enzyme: insights from parallel analysis of Notch 1 and APP proteolysis.
Notch receptors and the amyloid precursor protein are type I membrane proteins that are proteolytically cleaved within their transmembrane domains by a presenilin (PS)-dependent gamma-secretase activity. In both proteins, two peptide bonds are hydrolyzed: one near the inner leaflet and the other in the middle of the transmembrane domain. Under saturating conditions the substrates compete with each other for proteolysis, but not for binding to PS. At least some Alzheimer's disease-causing PS mutations reside in proteins possessing low catalytic activity. We demonstrate (i) that differentially tagged PS molecules coimmunoprecipitate, and (ii) that PS N-terminal fragment dimers exist by using a photoaffinity probe based on a transition state analog gamma-secretase inhibitor. We propose that gamma-secretase contains a PS dimer in its catalytic core, that binding of substrate is at a site separate from the active site, and that substrate is cleaved at the interface of two PS molecules.
Schroeter
Eric H
EH
Department of Molecular Biology and Pharmacology, Washington University School of Medicine, St. Louis, MO 63110, USA.
Ilagan
Ma Xenia G
MX
Brunkan
Anne L
AL
Hecimovic
Silva
S
Li
Yue-ming
YM
Xu
Min
M
Lewis
Huw D
HD
Saxena
Meera T
MT
De Strooper
Bart
B
Coonrod
Archie
A
Tomita
Taisuke
T
Iwatsubo
Takeshi
T
Moore
Chad L
CL
Goate
Alison
A
Wolfe
Michael S
MS
Shearman
Mark
M
Kopan
Raphael
R
D053829:Amyloid Precursor Protein Secretases; D016564:Amyloid beta-Protein Precursor / Q000378:metabolism*; D000818:Animals; D016282:Aspartic Acid Endopeptidases; D002460:Cell Line; D002478:Cells, Cultured; D019281:Dimerization; D010450:Endopeptidases / Q000378:metabolism*; D005347:Fibroblasts / Q000502:physiology; D006801:Humans; D008565:Membrane Proteins / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D051379:Mice; D018345:Mice, Knockout; D053764:Presenilin-1; D053766:Presenilin-2; D051881:Receptor, Notch1; D011956:Receptors, Cell Surface / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism; D014157:Transcription Factors; D014162:Transfection
D016564:Amyloid beta-Protein Precursor; D008565:Membrane Proteins; C497761:NOTCH1 protein, human; C497762:Notch1 protein, mouse; C508853:PSEN1 protein, human; C508861:PSEN2 protein, human; D053764:Presenilin-1; D053766:Presenilin-2; D051881:Receptor, Notch1; D011956:Receptors, Cell Surface; D011994:Recombinant Proteins; D014157:Transcription Factors; D053829:Amyloid Precursor Protein Secretases; D010450:Endopeptidases; D016282:Aspartic Acid Endopeptidases; C509280:BACE1 protein, human; C509282:Bace1 protein, mouse