title: Fibrillar aggregates of the tumor suppressor p53 core domain.
abstract: Alzheimer's disease, Parkinson's disease, cystic fibrosis, prion diseases, and many types of cancer are considered to be protein conformation diseases. Most of them are also known as amyloidogenic diseases due to the occurrence of pathological accumulation of insoluble aggregates with fibrillar conformation. Some neuroblastomas, carcinomas, and myelomas show an abnormal accumulation of the wild-type tumor suppressor protein p53 either in the cytoplasm or in the nucleus of the cell. Here we show that the wild-type p53 core domain (p53C) can form fibrillar aggregates after mild perturbation. Gentle denaturation of p53C by pressure induces fibrillar aggregates, as shown by electron and atomic force microscopies, by binding of thioflavin T, and by circular dichroism. On the other hand, heat denaturation produced granular-shaped aggregates. Annular aggregates similar to those found in the early aggregation stages of alpha-synuclein and amyloid-beta were also observed by atomic force microscopy immediately after pressure treatment. Annular and fibrillar aggregates of p53C were toxic to cells, as shown by MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] reduction assay. Interestingly, the hot-spot mutant R248Q underwent similar aggregation behavior when perturbed by pressure or high temperature. Fibrillar aggregates of p53C contribute to the loss of function of p53 and seed the accumulation of conformationally altered protein in some cancerous cells.
authors.affiliation: Departamento de Bioquímica Médica and Centro Nacional de Ressonância Magnética Nuclear, Universidade Federal do Rio de Janeiro, 21941-590 Rio de Janeiro, RJ, Brazil.
authors.forename: Daniella
authors.initials: D
authors.lastname: Ishimaru
authors.forename: Leonardo R
authors.initials: LR
authors.lastname: Andrade
authors.forename: Luciano S P
authors.initials: LS
authors.lastname: Teixeira
authors.forename: Pablo A
authors.initials: PA
authors.lastname: Quesado
authors.forename: Larissa M
authors.initials: LM
authors.lastname: Maiolino
authors.forename: Priscila M
authors.initials: PM
authors.lastname: Lopez
authors.forename: Yraima
authors.initials: Y
authors.lastname: Cordeiro
authors.forename: Lilian T
authors.initials: LT
authors.lastname: Costa
authors.forename: Wolfgang M
authors.initials: WM
authors.lastname: Heckl
authors.forename: Gilberto
authors.initials: G
authors.lastname: Weissmüller
authors.forename: Debora
authors.initials: D
authors.lastname: Foguel
authors.forename: Jerson L
authors.initials: JL
authors.lastname: Silva
mesh_terms: D000818:Animals; D002460:Cell Line; D006358:Hot Temperature; D006801:Humans; D008264:Macrophages / Q000187:drug effects / Q000378:metabolism; D051379:Mice; D018625:Microscopy, Atomic Force; D008854:Microscopy, Electron; D010084:Oxidation-Reduction / Q000187:drug effects; D011312:Pressure; D011489:Protein Denaturation; D017510:Protein Folding; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D013778:Tetrazolium Salts / Q000378:metabolism; D013844:Thiazoles / Q000378:metabolism; D016159:Tumor Suppressor Protein p53 / Q000737:chemistry* / Q000633:toxicity / Q000648:ultrastructure*
chemical_list: D013778:Tetrazolium Salts; D013844:Thiazoles; D016159:Tumor Suppressor Protein p53; C022616:thiazolyl blue