Ubiquitin (Ub) interacts non-covalently with Alzheimer amyloid precursor protein (betaPP): isolation of Ub-betaPP conjugates from brain extracts.
Ubiquitin (Ub)-immunocytochemistry on Alzheimer's disease (AD) brain sections shows diverse Ub-associated deposits in the neuropil and senile plaques, elevated levels of Ub reactivity in hippocampal neurons and glia, and co-localization of Ub and beta-amyloid precursor protein (betaPP) epitope reactivity in dystrophic axons. These observations may suggest a role for Ub and stress-related mechanisms in AD pathogenesis. Here we show for the first time that Ub interacts avidly but non-covalently with betaPP and such complexes, apparently formed in vivo, can be isolated from AD brain extracts by Ub-gel matrix affinity chromatography. Polyclonal antibodies specific to Ub and to different regions of betaPP were employed to characterize these proteins. The implication of Ub-betaPP complex formation is discussed in the context of betaPP processing.
Master
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Department of Microbiology and Immunology, McGill University, Montreal, Quebec, Canada.
Chan
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Ali-Khan
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D000368:Aged; D000369:Aged, 80 and over; D016564:Amyloid beta-Protein Precursor / Q000378:metabolism*; D001921:Brain / Q000378:metabolism*; D016022:Case-Control Studies; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D007120:Immunochemistry; D008875:Middle Aged; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D014020:Tissue Extracts / Q000378:metabolism*; D014452:Ubiquitins / Q000378:metabolism*
D016564:Amyloid beta-Protein Precursor; D009419:Nerve Tissue Proteins; D014020:Tissue Extracts; D014452:Ubiquitins