Binding of F-spondin to amyloid-beta precursor protein: a candidate amyloid-beta precursor protein ligand that modulates amyloid-beta precursor protein cleavage.
Amyloid-beta precursor protein (APP), a type I membrane protein, is physiologically processed by alpha- or beta-secretases that cleave APP N-terminal to the transmembrane region. Extracellular alpha-/beta-cleavage of APP generates a large secreted N-terminal fragment, and a smaller cellular C-terminal fragment. Subsequent gamma-secretase cleavage in the transmembrane region of the C-terminal fragment induces secretion of small extracellular peptides, including Abeta40 and Abeta42, which are instrumental in the pathogenesis of Alzheimer's disease, and intracellular release of a cytoplasmic tail fragment. Although APP resembles a cell-surface receptor, no functionally active extracellular ligand for APP that might regulate its proteolytic processing has been described. We now show that F-spondin, a secreted signaling molecule implicated in neuronal development and repair, binds to the conserved central extracellular domain of APP and inhibits beta-secretase cleavage of APP. Our data indicate that F-spondin may be an endogenous regulator of APP cleavage, and suggest that the extracellular domains of APP are potential drug targets for interfering with beta-secretase cleavage.
The Center for Basic Neuroscience, Department of Molecular Genetics, and Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, 6000 Harry Hines Boulevard, NA4.118, Dallas, TX 75390-9111, USA.
Angela
A
Ho
Thomas C
TC
Südhof
D016564:Amyloid beta-Protein Precursor / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D000818:Animals; D001921:Brain / Q000378:metabolism; D002460:Cell Line; D002846:Chromatography, Affinity; D016326:Extracellular Matrix Proteins; D006801:Humans; D006868:Hydrolysis; D036341:Intercellular Signaling Peptides and Proteins; D007700:Kinetics; D008024:Ligands; D010455:Peptides / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D051381:Rats; D011993:Recombinant Fusion Proteins / Q000302:isolation & purification / Q000378:metabolism; D014162:Transfection
D016564:Amyloid beta-Protein Precursor; D016326:Extracellular Matrix Proteins; D036341:Intercellular Signaling Peptides and Proteins; D008024:Ligands; D010455:Peptides; D011993:Recombinant Fusion Proteins; C429104:SPON1 protein, human; C498955:Spon1 protein, rat