Gamma-secretase is a membrane protein complex comprised of presenilin, nicastrin, Aph-1, and Pen-2.
gamma-Secretase catalyzes the intramembrane proteolysis of Notch, beta-amyloid precursor protein, and other substrates as part of a new signaling paradigm and as a key step in the pathogenesis of Alzheimer's disease. This unusual protease has eluded identification, though evidence suggests that the presenilin heterodimer comprises the catalytic site and that ... a highly glycosylated form of nicastrin associates with it. The formation of presenilin heterodimers from the holoprotein is tightly gated by unknown limiting cellular factors. Here we show that Aph-1 and Pen-2, two recently identified membrane proteins genetically linked to gamma-secretase, associate directly with presenilin and nicastrin in the active protease complex. Coexpression of all four proteins leads to marked increases in presenilin heterodimers, full glycosylation of nicastrin, and enhanced gamma-secretase activity. These findings suggest that the four membrane proteins comprise the limiting components of gamma-secretase and coassemble to form the active enzyme in mammalian cells.
Mesh Terms:
Amyloid Precursor Protein Secretases, Animals, Caenorhabditis elegans Proteins, Cricetinae, Cricetulus, Endopeptidases, Homeodomain Proteins, Membrane Glycoproteins, Membrane Proteins
Amyloid Precursor Protein Secretases, Animals, Caenorhabditis elegans Proteins, Cricetinae, Cricetulus, Endopeptidases, Homeodomain Proteins, Membrane Glycoproteins, Membrane Proteins
Proc. Natl. Acad. Sci. U.S.A.
Date: May. 27, 2003
PubMed ID: 12740439
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