title: A role for p53 in the beta-amyloid-mediated regulation of the lysosomal system.
abstract: Beta-amyloid accumulates around neurons in Alzheimer's disease and is thought to contribute to the neurodegenerative process. This study examined the role of the tumour suppressor protein, p53, in the neurodegenerative pathway, with focus on the interaction of p53 with the lysosomal system. beta-Amyloid increased expression of p53 and its transcription target, Bax, in cultured cortical neurons. In addition, A beta increased the association of phospho-p53(ser15) with the lysosomal compartment and this correlated with destabilization of the lysosomal membrane and a concomitant increase in cytosolic cathepsin-L activity. These effects of beta-amyloid were abolished by the p53 inhibitor, pifithrin-alpha, and siRNA-mediated knockdown of p53, demonstrating that p53 is a critical regulator of lysosomal integrity and the induction of cathepsin-L protease activity. In addition, activation of the apoptotic cascade was abolished by pifithrin-alpha. We conclude that p53 associates with the lysosome to regulate a lysosomal branch of the apoptotic cascade which contributes to beta-amyloid-mediated neurodegeneration.
authors.affiliation: Department of Physiology and Trinity College Institute of Neuroscience, Trinity College, Dublin 2, Ireland.
authors.forename: Marie P
authors.initials: MP
authors.lastname: Fogarty
authors.forename: Róisín M
authors.initials: RM
authors.lastname: McCormack
authors.forename: Janis
authors.initials: J
authors.lastname: Noonan
authors.forename: Declan
authors.initials: D
authors.lastname: Murphy
authors.forename: Aoife
authors.initials: A
authors.lastname: Gowran
authors.forename: Veronica A
authors.initials: VA
authors.lastname: Campbell
mesh_terms: D000544:Alzheimer Disease / Q000378:metabolism*; D016229:Amyloid beta-Peptides / Q000378:metabolism*; D000818:Animals; D000831:Animals, Newborn; D017209:Apoptosis / Q000187:drug effects; D052160:Benzothiazoles / Q000494:pharmacology; D056668:Cathepsin L / Q000032:analysis; D018929:Cell Culture Techniques; D002540:Cerebral Cortex / Q000187:drug effects / Q000378:metabolism; D008247:Lysosomes / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D009474:Neurons / Q000187:drug effects / Q000378:metabolism; D010750:Phosphoproteins / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D014050:Toluene / Q000031:analogs & derivatives / Q000494:pharmacology; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism*; D051028:bcl-2-Associated X Protein / Q000378:metabolism*
chemical_list: D016229:Amyloid beta-Peptides; D052160:Benzothiazoles; D010750:Phosphoproteins; D016159:Tumor Suppressor Protein p53; D051028:bcl-2-Associated X Protein; D014050:Toluene; C121565:pifithrin; D056668:Cathepsin L