Detergent-dependent dissociation of active gamma-secretase reveals an interaction between Pen-2 and PS1-NTF and offers a model for subunit organization within the complex.
Gamma-secretase is a member of a new class of proteases with an intramembrane catalytic site and cleaves numerous type I membrane proteins, including the amyloid beta-protein precursor (APP) and the Notch receptor. Biochemical and genetic studies have identified four membrane proteins as components of gamma-secretase: a heterodimeric form of presenilin (PS), composed of its N- and C-terminal fragments (PS-NTF and PS-CTF, respectively), a highly glycosylated, mature form of nicastrin (NCT), Aph-1, and Pen-2. However, it is unclear how these components interact physically with each other and assemble into functional complexes. We and others recently found that Aph-1 interacts with a less glycosylated, immature form of nicastrin as an intermediate toward full assembly of gamma-secretase. Here we show that (1) the detergent dodecyl beta-d-maltoside (DDM) mediates the dissociation and inactivation of active gamma-secretase in a concentration-dependent manner, (2) DDM-dependent dissociation of the active gamma-secretase complex generates two major inactive complexes (Pen-2-PS1-NTF and mNCT-Aph-1) and two minor inactive complexes (mNCT-Aph1-PS1-CTF and PS1-NTF-PS1-CTF), and (3) Pen-2 can also associate with the PS holoprotein in complexes devoid of NCT and Aph-1. Taken together, our results demonstrate that Pen-2 interacts with PS-NTF within active gamma-secretase and offer a model for how the components of active gamma-secretase interact physically with each other.
Fraering
Patrick C
PC
Center for Neurologic Diseases, Brigham & Women's Hospital and Harvard Medical School, Boston, Massachusetts 02115, USA.
LaVoie
Matthew J
MJ
Ye
Wenjuan
W
Ostaszewski
Beth L
BL
Kimberly
W Taylor
WT
Selkoe
Dennis J
DJ
Wolfe
Michael S
MS
D053829:Amyloid Precursor Protein Secretases; D000818:Animals; D016282:Aspartic Acid Endopeptidases; D016466:CHO Cells; D002460:Cell Line; D002868:Chromosomal Proteins, Non-Histone / Q000096:biosynthesis / Q000737:chemistry* / Q000235:genetics; D006224:Cricetinae; D003902:Detergents / Q000737:chemistry*; D019281:Dimerization; D010450:Endopeptidases / Q000096:biosynthesis / Q000737:chemistry* / Q000235:genetics; D004789:Enzyme Activation / Q000235:genetics; D005960:Glucosides / Q000737:chemistry; D006367:HeLa Cells; D006801:Humans; D008562:Membrane Glycoproteins / Q000096:biosynthesis / Q000235:genetics; D008565:Membrane Proteins / Q000096:biosynthesis / Q000737:chemistry* / Q000235:genetics; D008958:Models, Molecular; D008970:Molecular Weight; D010446:Peptide Fragments / Q000096:biosynthesis / Q000737:chemistry* / Q000235:genetics; D010447:Peptide Hydrolases; D021122:Protein Subunits / Q000096:biosynthesis / Q000737:chemistry* / Q000235:genetics; D014162:Transfection
D002868:Chromosomal Proteins, Non-Histone; D003902:Detergents; D005960:Glucosides; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; C469349:PSENEN protein, human; D010446:Peptide Fragments; D021122:Protein Subunits; C413604:nicastrin protein; C040358:dodecyl maltoside; C475154:APH1A protein, human; D053829:Amyloid Precursor Protein Secretases; D010450:Endopeptidases; D010447:Peptide Hydrolases; D016282:Aspartic Acid Endopeptidases; C509280:BACE1 protein, human