Mutant p53 aggregates into prion-like amyloid oligomers and fibrils: implications for cancer.
Over 50% of all human cancers lose p53 function. To evaluate the role of aggregation in cancer, we asked whether wild-type (WT) p53 and the hot-spot mutant R248Q could aggregate as amyloids under physiological conditions and whether the mutant could seed aggregation of the wild-type form. The central domains (p53C) of both constructs aggregated into a mixture of oligomers and fibrils. R248Q had a greater tendency to aggregate than WT p53. Full-length p53 aggregated into amyloid-like species that bound thioflavin T. The amyloid nature of the aggregates was demonstrated using x-ray diffraction, electron microscopy, FTIR, dynamic light scattering, cell viabilility assay, and anti-amyloid immunoassay. The x-ray diffraction pattern of the fibrillar aggregates was consistent with the typical conformation of cross β-sheet amyloid fibers with reflexions of 4.7 Å and 10 Å. A seed of R248Q p53C amyloid oligomers and fibrils accelerated the aggregation of WT p53C, a behavior typical of a prion. The R248Q mutant co-localized with amyloid-like species in a breast cancer sample, which further supported its prion-like effect. A tumor cell line containing mutant p53 also revealed massive aggregation of p53 in the nucleus. We conclude that aggregation of p53 into a mixture of oligomers and fibrils sequestrates the native protein into an inactive conformation that is typical of a prionoid. This prion-like behavior of oncogenic p53 mutants provides an explanation for the negative dominance effect and may serve as a potential target for cancer therapy.
Instituto de Bioquímica Médica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ 21941-902, Brazil.
Ana P D
AP
Ano Bom
Luciana P
LP
Rangel
Danielly C F
DC
Costa
Guilherme A P
GA
de Oliveira
Daniel
D
Sanches
Carolina A
CA
Braga
Lisandra M
LM
Gava
Carlos H I
CH
Ramos
Ana O T
AO
Cepeda
Ana C
AC
Stumbo
Claudia V
CV
De Moura Gallo
Yraima
Y
Cordeiro
Jerson L
JL
Silva
D019943:Amino Acid Substitution; D000682:Amyloid / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D052160:Benzothiazoles; D006801:Humans; D020125:Mutation, Missense; D009369:Neoplasms / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism / Q000628:therapy; D011328:Prions; D055503:Protein Multimerization; D020836:Protein Structure, Quaternary; D017433:Protein Structure, Secondary; D013844:Thiazoles / Q000737:chemistry; D016159:Tumor Suppressor Protein p53 / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D014961:X-Ray Diffraction
D000682:Amyloid; D052160:Benzothiazoles; D011328:Prions; C495901:TP53 protein, human; D013844:Thiazoles; D016159:Tumor Suppressor Protein p53; C009462:thioflavin T